Document Puyallup_doc_0cba28fe55

Puget Sound Lake Tapps American Lake Gravelly Lake Spanaway Lake Steilacoom Lake Ohop Lake Tanwax Lake Lake Kapowsin Swan Creek Puya llu p River C l o ver C ree k C h a m bers C r ee k Nis q ual l y R i v e r N i s q u a l l y Riv e r P u y a ll u p R i v e r C a r b o n R i v e r M a s h e l Ri ver Ni sq ua ll y R iv e r M u c k C r e e k M u c k C re e k L acam a s C r e ek C l e a r C re ek C la r k s Cr e ek Oho p C r e e k P u allup R iv er C lo v e r C r e ek S o u t h C r e ek T a nwa x C re ek N. Fork C . C. S e q u a l i tc he w Numerical Simulation of the Groundwater-Flow System in Chambers–Clover Creek Watershed and Vicinity, Pierce County, Washington Scientific Investigations Report 2011–5086 Prepared in cooperation with the Pierce Conservation District and the Washington State Department of Ecology U.S. Department of the Interior U.S. Geological Survey ---PAGE BREAK--- Cover: Photograph showing confluence of Chambers Creek and Leach Creek. Photograph taken by Don Russell, Chambers-Clover Creek project team member, 2009. ---PAGE BREAK--- Numerical Simulation of the Groundwater- Flow System in the Chambers–Clover Creek Watershed and Vicinity, Pierce County, Washington By Kenneth H. Johnson and Mark E. Savoca, U.S. Geological Survey; and Burt Clothier, Robinson-Noble Inc. Prepared in cooperation with the Pierce Conservation District and the Washington State Department of Ecology Scientific Investigations Report 2011–5086 U.S. Department of the Interior U.S. Geological Survey ---PAGE BREAK--- U.S. Department of the Interior KEN SALAZAR, Secretary U.S. Geological Survey Marcia K. McNutt, Director U.S. Geological Survey, Reston, Virginia: 2011 For more information on the USGS—the Federal source for science about the Earth, its natural and living resources, natural hazards, and the environment, visit http://www.usgs.gov or call 1–888–ASK–USGS. For an overview of USGS information products, including maps, imagery, and publications, visit http://www.usgs.gov/pubprod To order this and other USGS information products, visit http://store.usgs.gov Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Although this report is in the public domain, permission must be secured from the individual copyright owners to reproduce any copyrighted materials contained within this report. Suggested citation: Johnson, K.H., Savoca, M.E., and Clothier, Burt, 2011, Numerical simulation of the groundwater-flow system in the Chambers-Clover Creek Watershed and Vicinity, Pierce County, Washington: U.S. Geological Survey Scientific Investigations Report 2011–5086, 108 p. ---PAGE BREAK--- iii Contents Abstract Purpose and Description of Model Groundwater-Flow Geologic Hydrogeologic Hydraulic Groundwater-Flow Groundwater and Surface-Water Groundwater-Level Fluctuations Water Numerical Simulation of the Groundwater-Flow Spatial and Temporal Hydrogeologic Hydraulic Hydraulic Specific Storage Boundary Conditions and Implementation of MODFLOW Recharge Well River Drain General-Head Boundary Model Calibration Calibration Weights for Measured Initial Parameter Final Parameter Assessment of Steady-State Assessment of Transient Model Model Model-Derived Groundwater Model Simulations for Six Selected ---PAGE BREAK--- iv Figures Figure 1. Map showing location of Chambers-Clover Creek watershed and vicinity, Washington… 3 Figure 2. Map showing locations of model river, general head, spring and seep cells, domestic and public-supply wells, and irrigation wells, Chambers-Clover Creek watershed and vicinity, Washington… 9 Figure 3. Vertical section showing hydrogeologic units and numerical model layers, Chambers-Clover Creek watershed and vicinity, Washington… 10 Figure 4. Map showing distribution of average annual groundwater recharge from precipitation and return flow, Chambers-Clover Creek watershed and vicinity, Washington… 14 Figure 5. Map showing distribution of average annual groundwater recharge from return flow, Chambers-Clover Creek watershed and vicinity, Washington… 15 Figure 6. Graphs showing temporal discretization of selected model values, Chambers-Clover Creek watershed and vicinity, Washington… 16 Figure 7. Map showing the locations of wells used in model calibration, Chambers-Clover Creek watershed and vicinity, Washington… 22 Figure 8. Graphs showing sensitivity of the steady-state and transient calibrations to changes in parameter values, Chambers–Clover Creek watershed and vicinity, Washington… 23 Figure 9. Final parameter value distribution of river conductance, Chambers-Clover Creek watershed and vicinity, Washington… 27 Figure 10. Graph showing simulated and average measured water-level altitudes for the steady-state calibration, Chambers-Clover Creek watershed and vicinity, Washington… 29 Figure 11. Graph showing simulated and average measured stream baseflows for the calibrated model for steady-state conditions, Chambers–Clover Creek watershed and vicinity, 31 Figure 12. Graph showing average simulated and average measured water-level altitudes for the calibrated model for transient conditions, Chambers-Clover Creek watershed and vicinity, Washington… 34 Figure 13. Hydrographs of simulated and measured groundwater levels for the calibrated model for transient conditions, Chambers–Clover Creek watershed and vicinity, Washington… 35 Figure 14. Graph showing simulated and measured stream baseflows for the transient calibration, Chambers–Clover Creek watershed and vicinity, Washington… 39 Figure 15. Map showing simulated groundwater-level altitude change between the steady-state “base-simulation” and simulation 1, Chambers-Clover Creek watershed and vicinity, 43 Figure 16. Map showing simulated groundwater-level altitude change between the steady-state “base-simulation” and simulation 2, Chambers-Clover Creek watershed and vicinity, 45 Figure 17. Map showing simulated groundwater-level altitude change between the steady-state “base-simulation” and simulation 3, Chambers-Clover Creek watershed and vicinity, 46 Figure 18. Map showing simulated groundwater-level altitude change between the steady-state “base-simulation” and simulation 4, Chambers-Clover Creek watershed and vicinity, 48 ---PAGE BREAK--- v Figures—Continued Figure 19. Hydrographs of simulated groundwater levels for transient “base-simulation” and simulation 5 and difference, Chambers-Clover Creek watershed and vicinity, Washington… 50 Figure 20. Hydrographs of simulated groundwater levels for transient “base-simulation” and simulation 6 and difference, Chambers-Clover Creek watershed and vicinity, Washington… 51 Figure 21. Maps showing extent and thickness of hydrogeologic units simulated with the Layer-Property Flow package, Chambers-Clover Creek watershed and vicinity, Washington… 56 Figure 22. Maps showing final parameter value distributions of horizontal and vertical hydraulic conductivity, and specific storage coefficients, Chambers–Clover Creek watershed and vicinity, Washington… 66 Figure 23. Maps showing simulated water-level altitudes and residuals for the steady-state calibration, Chambers–Clover Creek watershed and vicinity, Washington… 96 Tables Table 1. Lithologic and hydrologic characteristics of hydrogeologic units, Chambers-Clover Creek watershed and vicinity, Washington… 5 Table 2. Summary of hydraulic conductivity values estimated from specific-capacity data and aquifer tests, by hydrogeologic unit Chambers-Clover Creek watershed and vicinity, 6 Table 3. Estimated annual water budget for the Chambers–Clover Creek watershed and vicinity, Washington, September 1, 2006–August 31, 7 Table 4. Initial hydraulic property values of hydrogeologic units used in the steady-state calibration, Chambers-Clover Creek watershed and vicinity, Washington… 11 Table 5. Final parameter values and factors used in the steady-state and transient calibrations, Chambers-Clover Creek watershed and vicinity, Washington………… 26 Table 6. Calibration statistics for the steady-state calibration by hydrogeologic unit and baseflow, Chambers-Clover Creek watershed and vicinity, Washington… 28 Table 7. Calibration statistics for the transient calibration by hydrogeologic unit and baseflow, Chambers-Clover Creek watershed and vicinity, Washington… 32 Table 8. Model-derived groundwater flow, Chambers-Clover Creek watershed and vicinity, Washington… 41 Table 9. Comparison of selected water budget components for the “base simulation” steady-state condition and simulation 1… 42 Table 10. Comparison of selected water budget components for the “base simulation” steady-state condition and simulations 2 and 3, Chambers-Clover Creek watershed and vicinity, 44 Table 11. Comparison of selected water budget components for the “base simulation” steady-state condition and simulations 3 and 4, Chambers-Clover Creek watershed and vicinity, 47 Table 12. Comparison of selected water budget components for the “base simulation” transient condition and simulations 5 and 6, Chambers-Clover Creek watershed and vicinity, 49 Table 13. Wells used in model calibration, Chambers-Clover Creek watershed, Washington.… ---PAGE BREAK--- vi Conversion Factors and Datum Inch/Pound to SI Multiply By To obtain Length Acre 03.4047 hectare (ha) Acre 0.004047 square kilometer (km2) foot (ft) 0.3048 meter mile (mi) 1.609 kilometer (km) section (640 acres or 1 mile2) 259.0 square hectometer (hm2) square mile (mi2) 259.0 hectare (ha) square mile (mi2) 259.0 square kilometer (km2) Temperature in degrees Celsius may be converted to degrees Fahrenheit as follows: °F=(1.8×°C)+32 Temperature in degrees Fahrenheit may be converted to degrees Celsius as follows: °C=(°F-32)/1.8 Datum Vertical coordinate information was referenced to the North American Vertical Datum of 1988 (NAVD88), referred to in this report as “sea level.” Horizontal coordinate information was referenced to the North American Datum of 1983 (NAD83) Altitude, as used in this report, refers to height above or below sea level. ---PAGE BREAK--- vii Well-Numbering System Wells in the state of Washington are assigned a local well number that identifies each well based on its location within a township, range, section, and 40-acre tract. For example, local well number 20N/02E-26C01 indicates that the well is in township 20 north of the Willamette Base Line, and range 2 east of the Willamette Meridian. The numbers immediately following the hyphen indicate the section (26) within the township. (Most townships in the model area are divided into 36-mi2 sections; however, Washington Territory Donation Land Claims of 1852- 55 predate the Public Lands Survey and are not regular 1-mi2 sections. These early Donation Land Claims are depicted on maps as irregularly sized and shaped sections and are assigned sequence numbers greater than 36.) The letter following the section gives the 40-acre tract of the section. The two-digit sequence number (01) following the letter is used to distinguish individual wells in the same 40-acre tract. A following the sequence number indicates a well that has been deepened. Willamette Meridian Willamette Base Line W A S H I N G T O N Study area SECTION 26 TOWNSHIP Well 20N/02E-26C01 A B C D E F G H J K L M N P Q R R. 2 E. T. 20 N. 1 2 3 4 5 6 7 12 13 18 19 24 25 30 31 32 33 34 35 36 ---PAGE BREAK--- viii This page is intentionally left blank. ---PAGE BREAK--- Abstract A groundwater-flow model was developed to contribute to an improved understanding of water resources in the Chambers–Clover Creek Watershed. The model covers an area of about 491 square miles in western Pierce County, Washington, and is bounded to the northeast by the Puyallup River valley, to the southwest by the Nisqually River valley, and extends northwest to Puget Sound, and southeast to Tanwax Creek. The Puyallup and Nisqually Rivers occupy large, relatively flat alluvial valleys that are separated by a broad, poorly drained, upland area that covers most of the model area. Chambers and Clover Creeks drain much of the central uplands and flow westward to Puget Sound. The model area is underlain by a northwest-thickening sequence of unconsolidated glacial (till and outwash) and interglacial (fluvial and lacustrine) deposits. Ten unconsolidated hydrogeologic units in the model area form the basis of the groundwater-flow model. Groundwater flow in the Chambers-Clover Creek Watershed and vicinity was simulated using the groundwater- flow model, MODFLOW-2000. The finite‑difference model grid comprises 146 rows, 132 columns, and 11 layers. Each model cell has a horizontal dimension of 1,000 by 1,000 feet, and the model contains a total of 123,602 active cells. The thickness of model layers varies throughout the model area and ranges from 1.5 feet in the A3 aquifer unit to 1,567 feet in the G undifferentiated unit. Groundwater flow was simulated for both steady-state and transient conditions. Steady-state conditions were simulated using average recharge, discharge, and water levels for the 24-month period September 2006– August 2008. Transient conditions were simulated for the period September 2006–August 2008 using 24 stress periods. Resource managers and local stakeholders intend to use the model to evaluate a range of water resource issues under both steady-state and transient conditions. Initial conditions for the transient calibration were developed from a 3-year “lead-in” period that used recorded precipitation and river levels, and temporal extrapolations of other boundary conditions. During model calibration, variables were adjusted within probable ranges to minimize differences between measured and simulated groundwater levels and stream baseflows. The model as calibrated to steady-state conditions has a standard deviation for heads and flows of 28.42 feet and 2.12 cubic feet per second, respectively; the model as calibrated to transient conditions has a standard deviation for heads and flows of 23.01 feet and 2.67 cubic feet per second, respectively. Simulated steady-state inflow to the model area from precipitation and secondary recharge was 477,266 acre-feet per year (acre-ft/yr) (79 percent of total simulated inflow), and simulated inflow from stream and lake leakage was 129,778 acre-ft/yr (21 percent of total simulated inflow). Simulated outflow from the model primarily was through discharge to streams, lakes, springs, seeps, and Puget Sound (559,192 acre-ft/yr; 92 percent of total simulated outflow), and withdrawals from wells (47,863 acre-ft/yr; 8 percent of total simulated outflow). Six scenarios were formulated and simulated using the calibrated model to provide representative examples of how the model can be used to evaluate the effects on groundwater levels and stream baseflows of potential changes in groundwater withdrawals, in consumptive use, and in recharge. Numerical Simulation of the Groundwater-Flow System in the Chambers–Clover Creek Watershed and Vicinity, Pierce County, Washington By Kenneth H. Johnson and Mark E. Savoca, U.S. Geological Survey; and Burt Clothier, Robinson-Noble Inc. ---PAGE BREAK--- 2 Numerical Simulation of the Groundwater-Flow System in the Chambers-Clover Creek Watershed Introduction In 1998, the Washington State Legislature established the Washington State Watershed Management Act (codified under RCW 90.82) to address the diminishing availability and quality of water and the loss of critical habitat for fish and wildlife. Watershed studies under this Act were begun in 1998 in the Chambers–Clover Creek Watershed (CCCW) Water Resources Inventory Area (WRIA 12) by a group of Initiating Governments and local stakeholders (the Planning Unit). Upon completion of a technical assessment of the watershed, some members of the Planning Unit concluded that additional data, including development of a numerical groundwater-flow model, would contribute to an improved understanding of water resources in the CCCW. In May 2006, the U.S. Geological Survey (USGS), in cooperation with Pierce Conservation District (serving as sponsoring agency for local public water suppliers and Pierce County Surface Water Management Division) and the Washington State Department of Ecology, began a project to characterize the groundwater-flow system in the CCCW and vicinity, and to integrate this information (Savoca and others, 2010) and other information into a numerical groundwater- flow model to contribute to an improved understanding of water resources in the CCCW. Purpose and Scope This report documents the development and calibration of a numerical model to simulate groundwater flow in the CCCW and vicinity. The model described in this report can be used to assess the impacts of groundwater withdrawals on groundwater levels and on streamflows during low-flow conditions. This report presents the information used to construct and calibrate the model, and provides assessments of numerical model performance in simulating measured hydrologic conditions, and a discussion of model limitations. Information used to construct and calibrate the numerical model was based on the work of Justin and others (2009), and Savoca and others (2010). Six scenarios were formulated and simulated using the calibrated model to provide representative examples of how the model can be used to evaluate the effects on groundwater levels and stream baseflows of potential changes in groundwater withdrawals, in consumptive use, and in recharge. Description of Model Area The model covers an area of about 491 square miles in western Pierce County, Washington (fig. and includes major hydrologic features that could be used as hydrologic boundaries of the groundwater-flow model of the CCCW and vicinity. The model area is bounded to the northeast by the Puyallup River valley, to the southwest by the Nisqually River valley, and extends northwest to Puget Sound, and southeast to Tanwax Creek which approximates the southeastern extent of the majority of water-bearing hydrogeologic units (Savoca and others, 2010). The model area is underlain by a northwest-thickening sequence of unconsolidated glacial (till and outwash) and interglacial (fluvial and lacustrine) deposits. Sedimentary and volcanic bedrock units underlie the unconsolidated deposits, and crop out in a few areas within deeply incised river valleys along the southern and southeastern margin of the model area. The Puyallup and Nisqually Rivers occupy large, relatively flat alluvial valleys that are separated by a broad, poorly drained, upland area that covers most of the model area. The northwest-flowing Puyallup River receives streamflow from several north-flowing streams (Swan, Clear, and Clarks Creeks) that originate within the northern uplands. Chambers and Clover Creeks drain much of the central uplands and flow westward to Puget Sound. Muck and Lacamas Creeks, and several small tributaries to the northwest-flowing Nisqually River, drain the southern part of the model area. Many stream reaches flow year-round, however, intermittent and ephemeral flow conditions also are common in many stream reaches, especially during the summer months. Springs are present throughout the model area, and contribute to late-summer baseflow to streams and year-round groundwater discharge to Puget Sound along shoreline bluffs. Major lakes in the model area include Steilacoom, Gravelly, American, and Spanaway. These lakes are likely of glacial (kettle) origin and generally reflect water levels in the shallow groundwater-flow system. Many smaller lakes in the area are associated with poorly drained wetland areas that typically form on glacial till deposits. The model area has a temperate marine climate with warm, dry summers, and cool, wet winters. Mean annual precipitation (average annual precipitation for 1971–2000) is 38.9 in. at Tacoma, and 43.1 in. at McMillin Reservoir (National Oceanic and Atmospheric Administration, 2007). Land-surface altitude in the model area ranges from sea level along the Puget Sound coast and the western extent of major river valleys to near 900 ft in hills along the southeastern and eastern margin of the model area. ---PAGE BREAK--- Introduction 3 Figure 1. Location of Chambers-Clover Creek watershed and vicinity, Washington. R. 05 E. T. 15 N. T. 15 N. T. 17 N. T. 18 N. T. 19 N. T. 20 N. T. 21 N. R. 04 E. R. 03 E. R. 02 E. R. 01 E. SR 7 SR 161 SR 512 I-5 I-5 SR 16 Puget Sound Lake Tapps American Lake Gravelly Lake Spanaway Lake Steilacoom Lake Ohop Lake Tanwax Lake Lake Kapowsin Swan Creek Puya llu p River C l o ver C re e k C h a m bers C r ee k Nis q ual l y R iv er N i s q u a l l y Riv e r P u y a ll u p R i v e r C a r b o n R i v e r M a s h e l Ri ver Ni sq ua ll y R iv e r M u c k C r e e k M u c k C re e k L acam a s C r e ek C l e a r C r e ek C la r k s Cr e ek Oho p C r e e k P u allup R iv er N. Fork C . C. C lo v e r C r e ek S ou t h C re ek T a nwa x C re ek S e q ua l i tc he w C r . M u r r ay C r e e k Tacoma Lakewood Federal Way Fife Puyallup Yelm Sumner Edgewood DuPont University Place Orting Milton Pacific Algona Auburn Rainier Fircrest Steilacoom Eatonville Roy Ruston Bonney Lake WRIA 10 WRIA 10 WRIA 12 WRIA 12 WRIA 11 WRIA 11 Base from U.S. Geological Survey digital data, 1983, 1:100,000 Universal Transverse Mercator projection, Zone 10 Horizontal Datum: North American Datum of 1983 (NAD 83) 47°00° 46°50' 47°20' 30' 20' 122°10' 122°40' 10' EXPLANATION 0 4 6 8 MILES 2 0 4 6 8 KILOMETERS 2 Boundary of model Boundary of Water Resource Inventory Area and number WASHINGTON Figure location ---PAGE BREAK--- 4 Numerical Simulation of the Groundwater-Flow System in the Chambers-Clover Creek Watershed Groundwater-Flow System This section describes the hydrogeologic units that constitute the groundwater-flow system in the model area and includes discussions of recharge, flow direction, discharge, exchange of water between the aquifer system and creeks, temporal fluctuations in groundwater levels, and water budget. This information was used to construct and calibrate the numerical model and is based on the work of Justin and others (2009), and Savoca and others (2010). Geologic Setting The most recent advance and retreat of continental glaciers in the Pleistocene epoch of the Quaternary Period left behind more than 3,000 ft of unconsolidated deposits in the Puget Lowland and about 2,000 ft of deposits within the model area. The Puget Lobe of the Cordilleran ice sheet has advanced and retreated several times into the Puget Lowland from the mountains of British Columbia since the beginning of the Quaternary and has left behind a complex sequence of alternating glacial and interglacial sediments. The Vashon Stade of the Fraser Glaciation was the most recent and extensive of the major advances. Glacial sediment typically includes (in order of deposition) outwash sand and gravels deposited by the advancing ice; glacial till (hard and poorly sorted mixture of clay, silt, sand, and gravel) and ice-contact material deposited beneath and adjacent to the ice; and outwash sand and gravels at the top of the sequence deposited by the retreating ice. Each major glacial interval was followed by an extended interglacial period during which fluvial, lacustrine, bog, and marsh deposition dominated. Interglacial deposits typically comprise clay, silt, or discontinuous lenses of sand and gravel or peat. Underlying the unconsolidated glacial and interglacial deposits are Tertiary bedrock units comprised mainly of sedimentary claystone, siltstone, sandstone, beds of coal, and volcanic rocks (Walters and Kimmel, 1968). Alpine glacial deposits are locally present within areas of exposed bedrock. Hydrogeologic Units Savoca and others (2010) delineated 11 hydrogeologic units in the model area (table Geologic units were grouped into hydrogeologic units, comprising aquifers and confining units, on the basis of lithologic (depositional facies, grain size, and sorting) and hydrologic (hydraulic conductivity and unit geometry) characteristics. Glacial deposits generally are heterogeneous, and although a glacial aquifer may be composed primarily of sand or gravel, it may locally contain varying amounts of clay or silt. Similarly, a confining layer composed predominantly of silt or clay may contain local lenses of coarse material. These variations in lithology may influence the occurrence and movement of groundwater at a scale that is likely too small to be adequately represented by the regional-scale groundwater-flow model constructed for this study. Local-scale variability in the distribution of glacial depositional facies often results in the formation of spatially discontinuous units of varying thickness. Therefore, some units are not spatially contiguous, and unit thickness may vary considerably over short distances throughout the model area (Savoca and others, 2010, figs. 3–12). Within the study area, aquifers primarily comprise glacial outwash but also may include coarse-grained interglacial deposits. The confining units primarily comprise fine- grained interglacial deposits but also may include glacial till or glaciolacustrine deposits. Unconsolidated glacial and interglacial aquifer and confining units are underlain by low-permeability Tertiary bedrock units, which Jones (1999) described as the basement confining unit. Unconfined and confined conditions are present in the groundwater-flow system and affect the movement and storage of groundwater. Unconfined conditions occur when the upper surface of the saturated zone (water table) is at atmospheric pressure and the water table is free to rise and decline, filling and draining pore space, respectively, in response to changes in groundwater recharge and discharge. Confined conditions occur when groundwater pressure exceeds atmospheric pressure due to the presence of a less permeable overlying unit that constrains the thickness of the saturated zone. Changes in fluid pressure or head under confined conditions in response to groundwater recharge and discharge are governed by the compressibilities of the fluid and the skeletal matrix of the unit and do not result in filling or draining pore space. Hydraulic Conductivity Horizontal hydraulic conductivity was estimated for the hydrogeologic units using specific-capacity data from drillers’ logs and results of aquifer tests conducted by environmental consulting firms (Savoca and others, 2010). Specific-capacity data were compiled and analyzed for 160 wells that had a driller’s log containing discharge rate, time of pumping, drawdown, static water level, well-construction data, and lithologic descriptions. Aquifer tests results were available for 43 public water supply wells. Median values of estimated hydraulic conductivity, from specific-capacity data, for the aquifers (table 2) are similar in magnitude to values compiled by Vaccaro and others (1998) for the Puget Sound lowlands, and to values reported by Freeze and Cherry (1979) for similar materials. Median values of estimated hydraulic conductivities for the confining units (table 2) probably are biased too high because the specific-capacity data were obtained from wells that are preferentially open to lenses of coarse material within finer grained material. These data therefore likely represent the more productive zones in these units and not the entire unit. ---PAGE BREAK--- Groundwater-Flow System 5 Table 1. Lithologic and hydrologic characteristics of hydrogeologic units, Chambers-Clover Creek watershed and vicinity, Washington. [Abbreviations: ft, feet] Hydrogeologic unit (Savoca and others, 2010) Principal model layer Lithologic and hydrologic characteristics [refer to Savoca and others (2010) for unit extent and thickness maps] AL Alluvial valley aquifer 1–3 The aquifer consists of alluvial silt, sand, and gravel and mudflow deposits that closely follow Holocene river valleys. The unit generally is less than 100 ft thick along the Nisqually River, but exceeds 250 ft along the Puyallup River as it nears Commencement Bay. Groundwater in this aquifer generally is unconfined; however, confined conditions may occur locally beneath mudflow deposits. A1 Aquifer 1 The aquifer primarily is composed of recessional outwash deposits consisting of stratified silt, sand and gravel deposited by large meltwater streams formed during the northward retreat of the Puget Lobe. Thickness typically ranges from a thin veneer (less than 35 ft) to approximately 150 ft, and locally exceeds 200 ft. Groundwater generally is unconfined in this aquifer. A2 Confining unit 2 This low-permeability unit is composed of Vashon till and lesser amounts of ice-contact, moraine and fine-grained glaciolacustrine deposits. The unit consists of various proportions of clay, silt, sand, and gravel, with locally occurring sand and gravel lenses capable of providing water for domestic use. Thickness averages about 60 ft but varies spatially from a thin veneer to approximately 150 ft, and locally exceeds 200 ft. A3 Aquifer 3 The aquifer is composed of Vashon advance outwash and lesser amounts of Pre-Fraser coarse-grained non-glacial deposits, and consists of well-sorted sand or sand and gravel, with lenses of silt and clay. Thickness averages about 75 ft, and locally exceeds 160 ft. Groundwater in this aquifer generally is confined by the overlying Vashon till, however, unconfined conditions may occur locally where the unit is not fully saturated or is exposed at land surface. B Confining unit 4 This low-permeability unit primarily is composed of fine-grained silts and clays deposited during the Olympia interglacial and glaciolacustrine clays deposited during early Vashon. Thickness averages about 55 ft, but locally exceeds 200 ft. C Aquifer 5 The aquifer is composed of pre-Olympia glacial drift deposits consisting of sand and gravel, with minor lenses of silt, clay, and till. Thickness averages about 105 ft, and locally exceeds 200 ft. Groundwater in this aquifer generally is confined by the overlying B confining unit. However, unconfined conditions may occur locally where no overlying confining unit is present, or in places where the aquifer is not fully saturated. D Confining unit 6 This low-permeability unit consists of alluvial and lacustrine sand, silt and clay deposits, and occasional deposits of volcanic ash. Thickness averages about 100 ft, and locally exceeds 200 ft. E Aquifer 7 The aquifer consists of silt, sand, and gravel, with discontinuous till and lacustrine deposits. Thickness typically ranges from a thin veneer to approximately 120 ft, and locally exceeds 200 ft. Groundwater in this aquifer is confined by the overlying D confining unit. F Confining unit 8 This low-permeability unit consists of silt and clay, with minor lenses of sand and gravel. Limited well data indicate thickness typically ranges from 50 to 200 ft, and locally exceeds 300 ft. G Undifferentiated deposits 9–11 Undifferentiated deposits assigned to unit G consist of stratified sand and gravel, with discontinuous layers of till. Few wells in the study area fully penetrate the unit, and little is known about the spatial distribution of water-bearing and non-water-bearing sediments in the deeper parts of the unconsolidated sequence. Several public water-supply systems in the study area withdraw water from the upper part of the unit. Bedrock unit – This low-permeability unit consists primarily of sedimentary claystone, siltstone, sandstone, beds of coal, and volcanic rocks. ---PAGE BREAK--- 6 Numerical Simulation of the Groundwater-Flow System in the Chambers-Clover Creek Watershed Estimates of horizontal hydraulic conductivity compiled from aquifer tests (table 2) conducted by environmental consulting firms (Carr/Associates Inc.,1988; Robinson-Noble Inc., written commun., 2009) were available for public supply wells only, and are biased toward the major water-producing aquifers in the model area. Aquifer-test data were not available for the AL and A1 aquifers or for any of the confining units. Recharge Because precipitation is the dominant source of water that recharges groundwater in the model area, it is reasonable to expect the volume of recharge to vary with the volume of precipitation. However, other factors, such as the permeability of surficial hydrogeologic units and land-cover characteristics also determine the volume of recharge. The distribution of recharge from precipitation in the model area was estimated by applying precipitation–recharge relations (Savoca and others, 2010) based on four separate regression equations developed for areas in Washington State by Bidlake and Payne (2001). The four regression equations compute recharge to aquifers and confining units in areas with or without tree cover. Recharge in areas where the percentage of impervious surfaces are greater than 50 percent was reduced by one-half according to the method of Bidlake and Payne (2001). The groundwater- flow system within the water-budget area (432 mi2) located within the larger model area, receives about 455,000 acre-ft or about 20 in. of recharge from precipitation during an average year (Savoca and others, 2010). Groundwater recharge also occurs through return flows from septic systems, outdoor (irrigation) use, and leakage from public water- system distribution lines; return-flow estimates used in the groundwater-flow model are discussed later in this report. Groundwater-Flow Directions Groundwater flow in unconsolidated aquifers generally is towards the northwest in the direction of Puget Sound, and towards the north and northeast in the direction of the Puyallup River (Savoca and others, 2010, figs. 16–21). The potential for vertical flow between aquifers is difficult to determine because extents and thicknesses of hydrogeologic units vary considerably throughout the model area, the presence of low-permeability deposits within and between aquifers is highly variable, and the data available for comparing water levels between adjacent units are widely spaced. Water-level differences between the A3 and C aquifers show the potential for downward vertical flow in western (vicinity of American, Gravelly, and Steilacoom Lakes) and eastern (along the bluffs of the Puyallup River valley) parts of the model area. The potential for upward groundwater movement, indicated by the presence of flowing wells, was observed at several locations within aquifer units in the Puyallup River valley. Discharge Groundwater in the model area discharges to streams, lakes, springs, marshes, and along coastal and river valley bluffs; as evaporation and transpiration of shallow groundwater; as submarine seepage to Puget Sound; and as withdrawals from wells. Groundwater discharge sustains the late-summer and early-fall streamflow (baseflow) in the model area. Groundwater discharge to streams in the model area was estimated to be 120.6 ft3/s (87,310 acre-ft/yr) in September 2007 and 127.4 ft3/s (92,230 acre-ft/yr) in July 2008 (Savoca and others, 2010). These estimates represent flow from contributing areas upstream of synoptic streamflow measurement sites (235.4 mi2) and do not include contributing areas in portions of the subbasins (28.1 mi2). The averaged, area-weighted groundwater discharge was estimated to be 126.8 ft3/s (91,800 acre-ft/yr), not including discharge to the Puyallup and Nisqually Rivers, which were not measured. This value includes area-weighted estimates of groundwater Table 2. Summary of hydraulic conductivity values estimated from specific-capacity data and aquifer tests, by hydrogeologic unit Chambers-Clover Creek watershed and vicinity, Washington. Hydrogeologic unit Number of wells Horizontal hydraulic conductivity (feet per day) Minimum Median Maximum From specific-capacity data AL Alluvial valley aquifer 10 36 328 3,779 A1 Aquifer 4 62 933 5,065 A2 Confining unit 5 1 18 144 A3 Aquifer 34 1 122 15,137 B Confining unit 5 4 21 120 C Aquifer 59 3 96 12,753 D Confining unit 3 18 29 32 E Aquifer 22 11 57 1,317 F Confining unit 1 131 G Undifferentiated deposits 17 7 33 936 From aquifer tests A3 Aquifer 9 229 588 3,228 C Aquifer 13 21 198 1,337 E Aquifer 15 12 214 1,519 G Undifferentiated deposits 6 11 39 163 ---PAGE BREAK--- Groundwater-Flow System 7 discharge for portions of stream reaches that were of synoptic measurement sites. An estimate of groundwater discharge to the Puyallup and Nisqually Rivers, along with submarine seepage to Puget Sound, was computed as a residual component (“other natural discharge”) in the water budget presented later in this report. Groundwater withdrawals from wells in the water-budget area in 2007 were estimated to be 58,500 acre-ft (Savoca and others, 2010). This quantity represents gross withdrawals and does not reflect return flows from septic systems, outdoor (irrigation) use, and leakage from public water-system distribution lines. Groundwater discharge also occurs at numerous springs in the model area, and spring locations and discharge have been previously reported in several studies. The total previously reported discharge of springs in the area is about 110 ft3/s (80,000 acre-ft/yr (Savoca and others, 2010). Groundwater and Surface-Water Interactions Stream reaches that either gained flow or lost flow from the shallow groundwater system were identified from synoptic measurements conducted during low-flow conditions in September 2007 and July 2008 (Savoca and others, 2010). Reaches upstream of the uppermost measurement sites on all streams, except at Swan Creek, gained flow from groundwater discharge. Intermediate reaches of most streams generally were losing or neutral (no substantial gain or loss), and the lowermost reaches were generally gaining. Substantial groundwater discharge to the lower reaches of Chambers, Clear, and Clarks Creeks also was measured and probably is due to significant incision of stream channels as they descend to Puget Sound or to the Puyallup River valley (Savoca and others, 2010). Groundwater-Level Fluctuations Seasonal changes in groundwater levels that follow a typical pattern for shallow wells in western Washington were observed in many wells in the model area (Justin and others, 2009). Water levels rose in autumn and winter when precipitation and river stage were high, and declined during spring and summer when precipitation and river stage were low. The peak groundwater levels lagged behind the peak streamflow by a few months, reflecting the storage characteristics of the groundwater system. Water levels in wells completed in the unconsolidated hydrogeologic units exhibited seasonal variations ranging from less than 1 to about 50 ft. The largest fluctuation in water level (78 ft) during the monitoring period (March 2007–September 2008) was measured in a well completed in the bedrock unit. Water Budget An approximate water budget for average precipitation during the study period (September 1, 2006–August 31, 2008) for the water-budget area (Savoca and others, 2010) is presented in table 3. Precipitation during the study period averaged an estimated 45 in/yr in the area. About 44 percent of precipitation enters the groundwater system as recharge. Almost one-half of this recharge (49 percent) discharges to the Puyallup and Nisqually Rivers or leaves the groundwater system as submarine discharge to Puget Sound. The remaining groundwater recharge discharges to streams (20 percent) and springs (18 percent), or is withdrawn from wells (13 percent). The estimated magnitude of discharge to Puget Sound is highly uncertain because it incorporates all the inaccuracies in the other water-budget component estimates, and no attempts have been made to measure it directly. Submarine groundwater discharge is a potentially significant unknown because it represents a potential groundwater resource that could be withdrawn without impact to freshwater instream flows. Table 3. Estimated annual water budget for the Chambers–Clover Creek watershed and vicinity, Washington, September 1, 2006– August 31, 2008. Water budget component Quantity Percent of total Inches per year Acre-feet per year Precipitation Fate of precipitation Surface runoff 3 65,700 7 Evapotranspiration 22 504,300 49 Groundwater recharge 20 455,000 44 Total precipitation 45 1,025,000 100 Fate of recharge Discharge to streams 4 91,800 20 Discharge to springs 3.5 80,000 18 Other natural discharge1 10 224,700 49 Withdrawals from wells 2.5 58,500 13 Total 20 455,000 100 1 Discharge to the Puyallup and Nisqually Rivers or submarine seepage to Puget Sound. ---PAGE BREAK--- 8 Numerical Simulation of the Groundwater-Flow System in the Chambers-Clover Creek Watershed Numerical Simulation of the Groundwater-Flow System Groundwater flow in the Chambers–Clover Creek Watershed and vicinity was simulated using the U.S. Geological Survey modular three-dimensional finite-difference groundwater-flow model, MODFLOW-2000 (Harbaugh and others, 2000). MODFLOW-2000 is a computer program that numerically solves the three-dimensional groundwater-flow equation for a porous medium using the finite-difference method. The modular design of MODFLOW-2000 uses packages to represent groundwater-flow system processes, such as recharge, groundwater flow, discharge, and interactions between the aquifer and surface-water bodies. The model described in this report was developed to simulate steady-state and transient conditions. Steady-state groundwater flow represents a groundwater system that is in a state of equilibrium: inflows into and outflows from the system are constant and equal, resulting in no changes in groundwater storage. Transient groundwater flow represents a dynamic system, in which variable inflows, outflows, and groundwater storage change with time. The simulation of steady-state conditions incorporates average annual values for recharge, discharge, and other groundwater-flow system processes. The simulation of transient conditions incorporates variations in recharge, discharge, and other groundwater-flow system processes. Resource managers and local stakeholders intend to use the model to evaluate a range of water resource issues under both long-term steady-state and short-term transient conditions. Spatial and Temporal Discretization The model area was subdivided, horizontally and vertically, into rectilinear blocks called cells. The hydraulic properties of the material in each cell are assumed to be homogeneous. A model grid of 146 rows, 132 columns, and 11 layers was used to represent the groundwater-flow system (fig. The model grid is aligned 45° counterclockwise from the north to allow model boundaries to more closely approximate the locations of Puget Sound, and the Puyallup and Nisqually River valleys. Each cell in the model grid has a uniform dimension of 1,000 by 1,000 ft, and the model contains a total of 123,602 active cells. The thickness of model layers varies throughout the model area. All 11 model layers are active throughout the entire model area, except where regional features such as underlying bedrock units or Puget Sound truncate the lateral extents of hydrogeologic units. The bottom of the model (typically the bottom of model layer 11) is an implicit no-flow boundary and coincides with the top of bedrock. The Layer Property Flow (LPF) package was used to assign hydraulic properties to model cells in each model layer based on the hydrogeologic unit present at that location within the model. The model simulates both steady-state and transient con­ ditions. The steady-state condition simulates average recharge, discharge, and water levels for the study period (September 2006–August 2008). The transient simulation period (September 2006–August 2008) was divided into 24 stress periods to represent temporal variations in recharge, discharge, and other groundwater-flow system processes. Each stress period comprises one time step to coincide with the frequency of data collected in the field, and because smaller time steps were not necessary for stable operation of the model. Initial conditions for the transient calibration of the model were developed from a 3-year “lead-in” period (September 2003–August 2006) designed to isolate the transient calibration period from potential inaccuracies associated with initial transient calibration start-up. The lead-in period used recorded precipitation and river levels, and extrapolations of other boundary conditions. Hydrogeologic Framework The hydrogeologic units (table 1) delineated by Savoca and others (2010) were used to represent the three- dimensional hydrogeologic framework in the model. Most units are not spatially contiguous throughout the model area, and unit thicknesses vary considerably over short distances. Each hydrogeologic unit was assigned a principal model layer (table 1) that most closely corresponds to the unit’s stratigraphic position in the aquifer system based on the unit top and thickness (fig. 21, at back of report). With the exception of the alluvial valley aquifer (AL) and undifferentiated deposits most units are represented by a single model layer, although overlying or underlying units can occupy a model layer in areas where the primary hydrogeologic unit assigned to the layer is absent. The relation between hydrogeologic units and model layers is illustrated in a vertical section through the model (fig. 3) that corresponds with hydrogeologic section A–A´ in Savoca and others (2010, pl. Tertiary sedimentary and volcanic bedrock units are assumed to be impermeable when compared to overlying unconsolidated units, and therefore, were not assigned a model layer. The top of the bedrock unit delineates the bottom of the model domain. A nearby groundwater-flow model by Drost and others (1999) characterized bedrock units in a similar manner. ---PAGE BREAK--- Numerical Simulation of the Groundwater-Flow System 9 R. 05 E. T. 15 N. T. 15 N. T. 17 N. T. 18 N. T. 19 N. T. 20 N. T. 21 N. R. 04 E. R. 03 E. R. 02 E. R. 01 E. Puget Sound Lake Tapps American Lake Gravelly Lake Spanaway Lake Steilacoom Lake Ohop Lake Tanwax Lake Lake Kapowsin Swan Creek Puya llu p River C l o ver C re e k C h a m bers C r ee k Nis q ual l y R iv er N i s q u a l l y Riv e r P u y a ll u p R i v e r C a r b o n R i v e r M a s h e l Ri ver Ni sq ua ll y R iv e r M u c k C r e e k M u c k C re e k L acam a s C r e ek C l e a r C r e ek C la r k s Cr e ek Oho p C r e e k P u allup R iv er C lo v e r C r e ek S ou t h C re ek T a nwa x C re ek N. Fork C . C. S e q ua l i tc he w C r . Base from U.S. Geological Survey digital data, 1983, 1:100,000 Universal Transverse Mercator projection, Zone 10 Horizontal Datum: North American Datum of 1983 (NAD 83) 47°00° 46°50' 47°20' 30' 20' 122°10' 122°40' 10' 0 4 6 8 MILES 2 0 4 6 8 KILOMETERS 2 Model boundary conditions River Irrigation wells Domestic wells Public water system wells General head boundaries EXPLANATION Boundary of Water Resource Inventory Area Boundary of active model Springs Seeps Figure 2. Locations of model river, general head, spring and seep cells, domestic and public-supply wells, and irrigation wells, Chambers-Clover Creek watershed and vicinity, Washington. ---PAGE BREAK--- 10 Numerical Simulation of the Groundwater-Flow System in the Chambers-Clover Creek Watershed C 0 10,000 20,000 30,000 40,000 50,000 60,000 70,000 FEET Model layers and No. Chambers Creek Puyallulp River Chambers Creek Br G F F D C A2 A1 1 2 3 5 6 7 8 10 11 AL A2 A3 A3 B B C G G E E D F 0 10,000 5,000 15,000 20,000 METERS 1 2 4 9 3 4 5 6 7 9 10 11 8 Swan Creek A3 B E E D F Br 10 AL– Alluvial valley aquifer Top of hydrogeologic unit A1– Aquifer A3– Aquifer A2– Confining unit B– Confining unit D– Confining unit G– Undifferentiated deposits Br– Bedrock F– Confining unit C– Aquifer E– Aquifer EXPLANATION 150 100 50 SEA LEVEL 600 400 200 2,000 1,400 1,200 1,000 200 400 600 800 FEET 150 100 50 500 450 400 300 250 200 350 550 600 0 600 400 200 2,000 1,400 1,200 1,000 200 400 600 800 METERS 1,800 1,600 1,800 1,600 FEET A A' E W Puget Sound NAVD 88 Figure 3. Hydrogeologic units and numerical model layers, Chambers-Clover Creek watershed and vicinity, Washington. ---PAGE BREAK--- Numerical Simulation of the Groundwater-Flow System 11 Hydraulic Properties The hydrogeologic units in the model area contain a variety of materials, and each unit likely exhibits a range in the spatial distribution of the values of hydraulic properties (hydraulic conductivity and specific storage) that is not well understood. Where available, initial estimates of values of hydraulic properties were obtained from previously published reports in and adjacent to the model area (Savoca and others, 2010), as well as from published values in a standard reference (Freeze and Cherry, 1979). A uniform distribution of hydraulic parameter values was initially specified in the numerical model for each hydrogeologic unit. Hydraulic Conductivity Initial values of horizontal hydraulic conductivity (Kh) for the hydrogeologic units (table 4) were based on analyses of specific- capacity data and results of aquifer tests (Savoca and others, 2010). Because there is no evidence to suggest that hydraulic conductivity varies with direction (no preferential flow), horizontal isotropy (Kx= Ky) was assumed. Initial values of horizontal hydraulic conductivity in aquifer units ranged from 198 ft/d in the C aquifer to 933 ft/d in the A1 aquifer. Initial values of horizontal hydraulic conductivity in confining units ranged from 18 ft/d in the A2 confining unit to 30 ft/d in the F confining unit. The G undifferentiated deposits were represented using an initial horizontal hydraulic conductivity value of 39 ft/d. Initial values of vertical hydraulic conductivity (Kv) were assigned to each hydrogeologic unit (table 4) as the ratio of horizontal to vertical hydraulic conductivity (vertical anisotropy). Assignment of vertical anisotropy to hydrogeologic units was based on unit lithologic and hydraulic characteristics, and initial vertical anisotropy values used in a nearby groundwater-flow model by Drost and others (1999). • Aquifers comprising primarily well-sorted sand and gravel (hydrogeologic units AL, A1, A3, C, and E) were assigned a vertical anisotropy of 10 (that is, Kh =10 × Kv); • Confining units comprising primarily poorly sorted and fine-grained deposits (hydrogeologic units A2, B, D, and F) were assigned a vertical anisotropy of 100. • The G undifferentiated deposits represent a composite of probable aquifers and intervening confining units and were assigned a vertical anisotropy of 30, which represents an intermediate value between an unconsolidated aquifer and a confining unit. Specific Storage Specific storage values were assigned to model cells to represent the change in groundwater storage that results from changes in water levels in a confined aquifer. Both unconfined and confined conditions occur within the groundwater system, however, in order to prevent the drying of model cells, and resultant model instability, all model layers were simulated as confined and specific storage values were assigned to all model cells. Values of specific storage in confined aquifers commonly range from 1.0 × 10–5 to 1.0 × 10–6 ft–1 (Riley, 1998), and values for clay-bearing confining units could be an order of magnitude larger, based on reported compressibility values (Freeze and Cherry, 1979). An initial specific storage value of 1.0 × 10–6 ft–1 was assigned to aquifer units A3, C, and E, and a larger value of initial specific storage (1.0 × 10–2 ft–1) comparable to specific yield of 1 percent was assigned to aquifer units AL and A1 to more closely represent the change in groundwater storage in unconfined aquifers (table An initial specific storage value of 1.0 × 10–5 ft–1 was assigned to all confining units, and an intermediate value of 3.0 × 10–6 ft–1 was assigned to the G undifferentiated deposits (table Table 4. Initial hydraulic property values of hydrogeologic units used in the steady-state calibration, Chambers-Clover Creek watershed and vicinity, Washington. [Descriptions of hydrogeologic units from Savoca and others (2010). Abbreviations: ft, feet ft/d, feet per day; ] Hydrogeologic unit Hydraulic conductivity (ft/d) Vertical anisotropy (Kh/Kv) Specific storage (ft-1) Horizontal (Kh) Vertical (Kv) AL Alluvial valley aquifer 328 33 10 1.0E-2 A1 Aquifer 933 93 10 1.0E-2 A2 Confining unit 18 0.2 100 1.0E-5 A3 Aquifer 588 59 10 1.0E-6 B Confining unit 21 0.2 100 1.0E-5 C Aquifer 198 20 10 1.0E-6 D Confining unit 29 0.3 100 1.0E-5 E Aquifer 214 21 10 1.0E-6 F Confining unit 130 0.3 100 1.0E-5 G Undifferentiated deposits 39 1.3 30 3.0E-6 1 Estimated value assigned to more closely approximate horizontal hydraulic conductivity of confining unit; value derived from analyses of limited specific-capacity data (table 2) for unit F (131 ft/d) was not used. ---PAGE BREAK--- 12 Numerical Simulation of the Groundwater-Flow System in the Chambers-Clover Creek Watershed Boundary Conditions and Implementation of MODFLOW Packages Specified-flux and head-dependent flux boundaries were used to represent hydrologic boundaries in the model. Specified-flux boundaries represent recharge from precipitation and discharge through groundwater withdrawals. Head-dependent flux boundaries represent groundwater discharge to rivers, lakes, springs, seeps, and Puget Sound. Specified-flux and head-dependent flux boundaries are implemented in the model using various MODFLOW packages and are described in the following sections. A no-flow boundary is inferred: along the Puyallup and Nisqually River valleys; along Tanwax Creek; and along the top of the bedrock surface beneath unconsolidated deposits. No-flow boundaries are specified flux boundaries with flux equal to zero—no groundwater flow is simulated across these boundaries. Groundwater flow beneath the Puyallup River valley is towards the north and northwest in the down-valley direction of the river, and a northwest down-valley groundwater flow direction also is likely beneath the Nisqually River valley (Savoca and others, 2010). Model boundaries were aligned sub-parallel to the direction of groundwater flow in the Puyallup and Nisqually River valleys to approximate no-flow conditions across the model boundary. Tanwax Creek approximates the southeastern extent of the majority of water bearing hydrogeologic units in the model area (Savoca and others, 2010). Relatively impermeable Tertiary sedimentary and volcanic bedrock units (Drost and others, 1999; Jones, 1999) are present near land surface southeast of Tanwax Creek and beneath unconsolidated water bearing units throughout the model area. It is assumed that the bedrock unit is impermeable when compared to the unconsolidated deposits overlying it; therefore, the contact between the top of the bedrock unit and overlying unconsolidated deposits is represented as a no-flow boundary. A nearby groundwater-flow model by Drost and others (1999) characterized the contact between bedrock and unconsolidated deposits in a similar manner. Recharge Package The Recharge Package was used to represent groundwater recharge from precipitation, and return flows from septic systems, outdoor (irrigation) use, and leakage from public water system distribution lines. Recharge (in units of feet per day) was applied as a specified flux to the uppermost model cell. The distribution of recharge from precipitation in the model area was estimated by applying precipitation–recharge relations (Savoca and others, 2010) based on regression equations developed for areas in Puget Sound, Washington (Bidlake and Payne, 2001). Recharge from precipitation was reduced by 50 percent in the Puyallup and Nisqually River valleys to account for losses due to evapotranspiration of shallow groundwater, and the likely rejection of some amount of precipitation recharge due to high water levels and periodic saturated conditions within the river valleys (Robinson-Noble Inc., oral commun., 2011). Residential return flows were represented as a percentage of the water used at residences with septic systems. A total residential return-flow rate (indoor and outdoor use) of 76 percent was used in the steady-state calibration, and closely correlates with total return-flow rates used in other groundwater studies in western Washington (Sapik and others, 1989; Drost and others, 1999; van Heeswijk and Smith, 2002; Geoengineers, 2003). The steady-state residential return-flow estimate (228 gal/d per connection) is based on a typical per connection water-use rate in these same references. Residential return-flow estimates used in the transient calibration were adjusted to account for temporal variations in outdoor use. During the winter months (October through April), outdoor use (lawn and garden irrigation) is assumed to be zero. Therefore, water use during the winter is entirely for indoor use, and an indoor return-flow rate of 87 percent was used to represent septic-system return flows during the winter. This indoor (winter) return-flow rate is similar to the winter rate used in a groundwater study in western Washington (Geoengineers, 2003). The indoor return-flow estimate (151 gal/d per connection) used in the transient calibration is based on a per connection indoor water-use rate estimate of 173 gal/d that was derived from an analysis (Ron Lane, U.S. Geological Survey, written commun., 2009) of reported public water system pumpage data for Pierce County, Washington. An outdoor use residential return-flow rate of about 40 percent was used in the transient calibration to represent lawn and garden irrigation return flows during the summer months (May–September). A similar outdoor residential use return-flow rate was recently used in a groundwater study in eastern Washington (Hsieh and others, 2007), and a quantitative field study of consumptive use associated with lawn watering by Oad and others (1997) estimates an efficiency of 60 percent and deep percolation of 40 percent of applied lawn water. Several methods have been used to determine return-flow rates associated with lawn and garden irrigation resulting in a wide range of published return-flow rate values (Oad and DiSpigno, 1997). These return-flow rates are based on studies representing conditions that may not be descriptive of conditions in the model area. Lawn and garden irrigation return-flow rates may vary spatially in the model area, and the return-flow rate used in the model is only an approximation based on limited data. Residential return flows were spatially distributed to cells according to the number of residences in each cell that had septic systems. Locations of residences were based on a mapping of known septic systems that was developed by the Tacoma Pierce County Health Department. ---PAGE BREAK--- Numerical Simulation of the Groundwater-Flow System 13 Return flows associated with public water system conveyance losses were represented as a percentage of the water pumped to public water system-service areas. An estimated conveyance loss return-flow rate of 10 percent was used in the steady-state and transient calibrations to simulate delivery losses that occur along water lines within service areas. This estimate of return-flow rate is based on an average of reported values for conveyance loss that several public water supply systems in the model area provided. The total estimated conveyance loss return-flow for each public water supply service area was uniformly distributed among all the model cells that had significant residential development (based on more than four improved parcels per cell) within the combined service areas. The distribution of recharge is shown in figure 4 in terms of average annual total recharge (precipitation and return flows), and the amount of total recharge that is attributed to return flows (septic, outdoor use, and conveyance loss) is shown in figure 5. The temporal distribution of residential and public water system return flows in the transient calibration was based on an analysis of public water system pumpage data for Pierce County, Washington, conducted by the USGS (Ron Lane, written commun., 2009). The temporal discretization of recharge (precipitation recharge, residential return flow, and conveyance loss) used in the transient calibration is shown in figure 6 as relative stress level factors that increase or decrease the values used in the steady-state calibration. During the winter (October–April), a constant return flow rate (151 gal/d per rural connection) was used to reflect primarily indoor water use during the winter months. In the summer (May–September) precipitation recharge decreases proportionally to the precipitation during each month, and increased residential and public supply withdrawals (due to increased outdoor water use) result in increased rural residential return flows that peak (378 gal/d per connection) in July. Well Package The Well Package was used to represent groundwater withdrawals (in units of cubic feet per day) from pumping wells. The spatial distribution of public-supply, domestic, and irrigation withdrawals is shown in figure 2. The Well Package imposes a specified-flux boundary condition in each model cell to which a well is assigned based on the withdrawal rate for each well or group of pumping wells located in the cell. Average annual withdrawals were used for steady-state conditions. Withdrawals for transient conditions were specified for each stress period and are shown in figure 6 as relative stress-level factors that increase or decrease the values used in the steady-state conditions. The distribution of withdrawal among model layers was based on the reported depths of public-supply and domestic wells, the estimated depths of irrigation wells, and the hydrogeologic framework, as reported in from Savoca and others (2010). Public-supply withdrawals were assigned to model layers using well construction records (depth of open interval) from the Sentry system maintained by the Washington State Department of Health (accessed January, 2010, at fortress.wa.gov/doh/eh/portal/odw/si/Intro.aspx) to identify the corresponding hydrogeologic unit and model layer (table Model layer assignments for public water supply wells were confirmed, when possible, by hydrogeologic interpretations of drillers’ logs, or by personal communications with the purveyor. Domestic well withdrawals were assigned to model layers using well construction records (depth of open interval) obtained from the Tacoma–Pierce County Health Department (Brad Costello, written commun., 2010). Locations of irrigation wells were obtained from a 2008 crop distribution database for Pierce County as compiled by the Washington State Department of Agriculture (accessed April, 2009 at http://www.agr.wa.gov/PestFert/natresources/ AgLandUse.aspx), and withdrawals were assigned to model layers based on the assumption that most irrigation wells in the model area withdraw water from the first reliable source of water encountered during well drilling, typically the advance outwash aquifer (A3 aquifer) where it is present, or the alluvial valley aquifer (AL aquifer), in the Puyallup Valley where many of the irrigation wells are located. This assumption is supported by the inventory of well records compiled by Savoca and others (2010), in which most of the wells in the model area were open to the A3 aquifer. Therefore, irrigation well withdrawals were assigned to the A3 or AL aquifers, if present (generally using the middle layer of the AL aquifer, which normally spanned three model layers). In a few cases in which an aquifer was not present, irrigation well withdrawals were assigned to the A2 confining unit. Groundwater withdrawals in 2007 are estimated to be about 48,000 acre-ft from wells in the 491 mi2 model area, a value which is less than the 58,500 acre-ft estimated by Savoca and others (2010) for their 432 mi2 water-budget area. Refinements in public-water withdrawal estimates and the exclusion of withdrawals from wells in bedrock units resulted in a decrease in total estimated groundwater withdrawals from the model area. ---PAGE BREAK--- 14 Numerical Simulation of the Groundwater-Flow System in the Chambers-Clover Creek Watershed R. 05 E. T. 15 N. T. 15 N. T. 17 N. T. 18 N. T. 19 N. T. 20 N. T. 21 N. R. 04 E. R. 03 E. R. 02 E. R. 01 E. Puget Sound Lake Tapps American Lake Gravelly Lake Spanaway Lake Steilacoom Lake Ohop Lake Tanwax Lake Lake Kapowsin Swan Creek Puya llu p River C l o ver C re e k C h a m bers C r ee k Nis q ual l y R iv er Ni squally Riv er P u y a ll u p R i v e r C a r b o n R i v e r M a s h e l Ri ver Ni sq ua ll y R iv e r M u c k C r e e k M u c k C re e k L acam a s C r e ek C l e a r C r e ek C la r k s Cr e ek Oho p C r e e k P u allup R iv er C lo v e r C r e ek S ou t h C re ek T a nwa x C re ek N. Fork C . C. S e q ua l i tc he w C r . Base from U.S. Geological Survey digital data, 1983, 1:100,000 Universal Transverse Mercator projection, Zone 10 Horizontal Datum: North American Datum of 1983 (NAD 83) 47°00° 46°50' 47°20' 30' 20' 122°10' 122°40' 10' 0 4 6 8 MILES 2 0 4 6 8 KILOMETERS 2 EXPLANATION Boundary of Water Resource Inventory Area Boundary of active model Water (no recharge) 26 to 35 21 to 25 16 to 20 11 to 15 5 to 10 Distribution of average annual groundwater recharge from precipitation and return flow, in inches per year Figure 4. Distribution of average annual groundwater recharge from precipitation and return flow, Chambers-Clover Creek watershed and vicinity, Washington. ---PAGE BREAK--- Numerical Simulation of the Groundwater-Flow System 15 Figure 5. Distribution of average annual groundwater recharge from return flow (septic, outdoor use, and conveyance loss), Chambers-Clover Creek watershed and vicinity, Washington. R. 05 E. T. 15 N. T. 15 N. T. 17 N. T. 18 N. T. 19 N. T. 20 N. T. 21 N. R. 04 E. R. 03 E. R. 02 E. R. 01 E. Puget Sound Lake Tapps American Lake Gravelly Lake Spanaway Lake Steilacoom Lake Ohop Lake Tanwax Lake Lake Kapowsin Swan Creek Puya llu p River C l o ver C re e k C h a m bers C r ee k Nis q ual l y R iv er Ni squally Riv er P u y a ll u p R i v e r C a r b o n R i v e r M a s h e l Ri ver Ni sq ua ll y R iv e r M u c k C r e e k M u c k C re e k L acam a s C r e ek C l e a r C r e ek C la r k s Cr e ek Oho p C r e e k P u allup R iv er C lo v e r C r e ek S ou t h C re ek T a nwa x C re ek N. Fork C . C. S e q ua l i tc he w C r . Base from U.S. Geological Survey digital data, 1983, 1:100,000 Universal Transverse Mercator projection, Zone 10 Horizontal Datum: North American Datum of 1983 (NAD 83) 47°00° 46°50' 47°20' 30' 20' 122°10' 122°40' 10' 0 4 6 8 MILES 2 0 4 6 8 KILOMETERS 2 EXPLANATION Boundary of Water Resource Inventory Areaer Boundary of active model Distribution of average annual groundwater recharge from return flow (septic, outdoor use, conveyance loss), in inches per year No return flows 0.1 to 0.5 0.6 to 1.0 1.1 to 2.0 2.1 to 3.0 3.1 to 7.7 ---PAGE BREAK--- 16 Numerical Simulation of the Groundwater-Flow System in the Chambers-Clover Creek Watershed 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 A 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 0 1 2 3 4 5 6 7 C S O 2006 2007 2008 N D J F M A M J J D J F M A M J J A A S O N S O 2006 2007 2008 N D J F M A M J J D J F M A M J J A A S O N S O 2006 2007 2008 N D J F M A M J J D J F M A M J J A A S O N Relative stress factor (steady-state = 1.0) Relative stress factor (steady-state = 1.0) Relative river stage, in feet or blue as factor Relative Stage (ft) in Nisqually River (Gage 12089500) Relative Stage (ft) in Puyallup River (Gage 12101500) Relative Stage (ft) in Puyallup River (Gage 12096500) Relative Stage (ft) in Puyallup River (Gage 12093500) Relative depth (factor) in other streams (steady state = 1.0) Withdrawals from crop irrigation wells Precipitation recharge EXPLANATION EXPLANATION EXPLANATION Conveyance loss + lawn irrigation Residential return flows (septic and lawn + garden irrigation) Withdrawals from residential and public water-system wells B Figure 6. Temporal discretization of selected model values, Chambers-Clover Creek watershed and vicinity, Washington. ---PAGE BREAK--- Numerical Simulation of the Groundwater-Flow System 17 Groundwater withdrawals for Group A (15 or more connections, or at least 25 residents) and for Group B (fewer than 15 connections or less than 25 residents) public water- supply systems (43,540 acre-ft) were estimated using typical per capita water-use rates of 138 and 109 gal/d, respectively. These typical use rates were based on reported withdrawals from several public water purveyors in the area, and groundwater withdrawal and use data collected by the USGS (Ron Lane, written commun., 2009). Well withdrawals for transient conditions were calculated by multiplying steady- state withdrawals by a factor derived from reported withdrawals from public water purveyors in the area (Ron Lane, written commun., 2009) to account for year-round indoor use of about 173 gal/d per connection, and summertime outdoor water use that reaches a maximum of about 205 gal/d per connection in July (fig. Public water-supply system service populations were obtained from the Washington State Department of Health Sentry public water system database (accessed January 2010, at portal/odw/si/Intro.aspx). Self-supplied domestic groundwater withdrawals (305 acre-ft/yr) were estimated using a typical per capita water use rate of 228 gal/d per connection, and a database of the individual wells in the area (Brad Costello, Tacoma–Pierce County Health Department, oral. commun., 2010). Groundwater withdrawals for the irrigation of golf courses, cemeteries, and agricultural crops (4,018 acre-ft/yr) were estimated using crop irrigation requirement (CIR) rates based on crop type and irrigation method from the Washington State Department of Agriculture (accessed April 2009, at http://www.agr.wa.gov/pestfert/natresources/giscropdata. aspx). variations in crop irrigation were based on the irrigation needs for turf obtained from the Washington State Department of Agriculture Irrigation Guide: Appendix A (accessed April 2009, at http://www.wa.nrcs.usda.gov/ technical/ENG/irrigation_guide/index.html) since many of the reported irrigation wells were for golf courses. River Package The River Package was used to represent the exchange of water between rivers and lakes and the aquifer system. Model cells used in the River Package are shown in figure 2. In the River Package, a river reach refers to the section of a river within a model cell. For a river reach, the volumetric flow rate across the riverbed to the underlying model cell is computed as ( ) 3 2 , where is the flow rate across the riverbed (ft /day), is the conductance of the riverbed (ft /day), is the river stage (ft), and is the hydraulic head (ft) in the cell underlying th rb rb r a rb rb r a Q C h h Q C h h = − e riverbed when the bottom of the riverbed is below the water table in the cell; is the altitude of the bottom of the riverbed (ft) when the bottom of the riverbed is above the hydraulic head in the a h cell. The conductance of the riverbed is given by / , where is the vertical hydraulic conductivity of the riverbed sediment (ft/day), is the width of the river reach (ft), is the length of the river reach (ft), and is the thickness of the r rb v v C K wL m K w L m = iverbed sediment (ft). Conductance of the riverbed, ,is specified in the model. rb C River stage was estimated using Light Detection and Ranging (LiDAR) derived altitudes along river channels (accessed January 2010 at http://pugetsoundlidar.ess. washington.edu/). Riverbed conductance was computed from the channel area and estimates of the riverbed thickness and vertical hydraulic conductivity. The channel area within a model cell was calculated by summing area calculations for the short line segments in that cell. The width of the river channel at any point was based on the National Hydrography Dataset (accessed January 2010 at http://nhd.usgs.gov/index. html and NHD Plus, http://www.horizon-systems.com/ and those widths were confirmed by river cross- section measurements at stream gages and at stream base-flow measurement sites (Savoca and others, 2010). The thickness of the riverbed at any point was estimated as a function of the depth of the river at the point, based on depth measurements at gage and baseflow sites (Savoca and others, 2010). The vertical hydraulic conductivity of the riverbed was based on the vertical hydraulic conductivity of the hydrogeologic unit underlying each river reach (Savoca and others, 2010). ---PAGE BREAK--- 18 Numerical Simulation of the Groundwater-Flow System in the Chambers-Clover Creek Watershed The riverbed conductances of all river channels in a model cell were summed to get the total riverbed conductance for that cell; river stage in the cell was based on the average of LiDAR- derived altitudes for the river points in the cell. In the transient calibration, the widths of rivers (except the Puyallup and Nisqually River) were estimated to vary seasonally according to variations in streamflows measured at several stream-gage sites in the model area, and riverbed conductance values were adjusted during model calibration by a river stage factor (fig. 6) to reflect temporal changes in river width. Temporal changes in river depth also were adjusted, by the same factor for changes in stage. An average steady-state river stage was assigned to each model cell along the Puyallup and Nisqually Rivers for the steady-state period, based on LiDAR measurements, as had been done for all the other river cells. These river stage values for the Puyallup and Nisqually Rivers were then modified in the transient calibration, using a linear interpolation of variations of the river stages between USGS gage data, including an unchanging sea-level stage at the mouths of the rivers. (Tidal levels in Puget Sound were considered to change too rapidly to include in the time-step data.) The width and depth of the Puyallup and Nisqually Rivers were estimated based on the National Hydrography Dataset and confirmed by surveyed cross-section data by Czuba and others (2010). Widths of these major rivers were not changed in the transient calibration, but the stages were adjusted from gage data, as discussed above. The River Package also was used to represent the exchange of water between the aquifer system and lakes that receive inflow from and (or) provide outflow to streams (Spanaway, Steilacoom, American, and Sequalitchew Lakes, and several smaller lakes). Transient variations in lake stage were based on water levels recorded by the Pierce Conservation District Stream Team and Lakewood Water District (Robinson Noble Inc., written commun., 2009) and were adjusted in accordance with the stages of the streams flowing into or out of them. The vertical hydraulic conductivity of lakebed sediments was based on the vertical hydraulic conductivity of the underlying hydrogeologic units. Lake depths reported by the Washington State Departments of Ecology (accessed April, 2009 at http://www.ecy.wa.gov/ programs/eap/wsb/pdfs/WSB_43a_Book.pdf and http://www. ecy.wa.gov/programs/eap/wsb/pdfs/WSB_43c_Book.pdf) were used to identify hydrogeologic units beneath lakes. Drain Package The Drain Package is used to represent groundwater discharge to springs, and groundwater seepage along bluffs adjacent to the Puyallup and Nisqually River valleys and bluffs along Puget Sound (fig. The simulated volume of groundwater discharge at a drain cell is equal to the product of a drain conductance and the difference between the simulated water level in the drain cell and the drain altitude. The conductance of a drain cell is a function of the hydraulic conductivity of the surrounding hydrogeologic material and the cell geometry. Spring locations and discharge were compiled from previous investigations (Blair, 1929; Sceva and others, 1955; Walters and Kimmel, 1968; Jones and others, 1999). Drain altitudes were estimated using LiDAR-derived elevation values and information about the hydrogeologic unit that was most probably discharging water to the spring at that location. General-Head Boundary Package The General-Head Boundary Package is used to represent the exchange of water between the aquifer system and Puget Sound (fig. An unquantified amount of groundwater flow out of the model occurs along the western extent of the model as submarine seepage to Puget Sound along part of the western extent of model layers 1, 4, 5, 6, 7, and 8 (hydrogeologic units AL, B, C, D, E, and Groundwater flow into or out of each cell (Qb) is computed as ( ) 2 – , where is the boundary conductance (ft per day), is the hydraulic head on the outside of the model boundary (ft), and is the hydraulic head in the model cell (ft). b b b a b b a Q C h h C h h = The hydraulic head on the outside (hb) of the model boundary for each cell was specified as sea level, adjusted according to the depth of Puget Sound at that location and the unit weight of sea water. The value of conductance (Cb) at general head boundary cells was based on the conductivity of the surrounding hydrogeologic material. The largest conductance values were assigned to cells representing aquifers in contact with Puget Sound (5,075,089 ft2/d in the AL aquifer unit); the lowest conductance values were assigned to cells representing confining units in contact with Puget Sound (33,026 ft2/d in the B confining unit). ---PAGE BREAK--- Numerical Simulation of the Groundwater-Flow System 19 Model Calibration Model calibration is the adjustment of model parameters so that the differences (residuals) between measured and simulated groundwater levels and stream baseflows are minimized with respect to an objective function. This section of the report describes the method used for calibration, the calibration data, and the calibration results. The calibration is assessed by examining how well the simulated quantities fit the measured quantities from previous investigations (Justin and others, 2009; Savoca and others, 2010). Values of horizontal and vertical hydraulic conductivity and conductance values for the specified-flux boundary conditions were estimated through steady-state calibration, and values of specific storage were estimated through transient calibration. Calibration Procedure The parameter estimation program PEST (Doherty, 2005, 2006), enhanced with Pilot-Point Parameterization (Doherty, 2003; Doherty and others, 2010), Tikhonov Regularization (Doherty, 2003; Fienen and others, 2009) and Singular Value Decomposition (Doherty and Hunt, 2010), was used to calibrate the groundwater-flow model. PEST automatically adjusted model parameters (horizontal and vertical hydraulic conductivity, specific storage, and river, drain, seep, and general head boundary conductance) through a series of model runs. After each run, simulated groundwater levels and stream baseflows were compared to measured values. Model runs continued until the differences (residuals) between simulated and observed values were minimized. PEST implements a nonlinear least-squares regression method (Gauss-Marquardt- Levenberg) to estimate model parameters by minimizing the sum of squared weighted residuals (objective function): 2 1 th th th th ( ) , where is the number of measurements, is the weight for the measured quantity, and is the residual, defined as the measured quantity minus the corresponding simulated qu N i i i i i w r N w i r i i i = Φ = ∑ antity. Details of this method are given in the PEST user’s manual (Doherty, 2005, 2006). The weight, wi, reflects the uncertainty in a measurement and affects the importance of the ith measured quantity in the regression. A measurement with a small uncertainty (large wi) asserts a larger influence on the regression than does a measurement with a large uncertainty (small wi). Pilot-point parameterization was used to represent spatial heterogeneity in horizontal and vertical hydraulic conductivity and specific storage. Pilot points were evenly distributed over the entire model domain by hydrogeologic unit at 140 locations and were used as surrogate parameters at which values for horizontal and vertical hydraulic conductivity were estimated during steady-state calibration. These pilot points were supplemented with 42 additional pilot points at the locations of aquifer tests, and were assigned initial values of horizontal hydraulic conductivity based on the reported transmissivity and the estimated aquifer thickness at the aquifer test location. During transient calibration all 182 pilot point locations were used to estimate specific storage. Estimated values of horizontal and vertical hydraulic conductivity and specific storage at pilot points were interpolated to the entire model domain using kriging (a geostatistical algorithm) procedures in PEST in such a way that the heterogeneity in hydraulic conductivity and specific storage could be represented at a much lower computational cost than trying to estimate parameter values at every model cell. Groundwater-flow models with many parameters are commonly affected by parameter insensitivity and correlation, which in turn lead to solution non-uniqueness and an ill-posed inverse problem. The Preferred-Homogeneity condition of Tikhonov regularization was used to mitigate these problems in the CCCW model. This approach facilitates geologic continuity where it is believed to exist but still allows heterogeneity to be expressed within hydrogeologic units as informed by groundwater-level and stream baseflow measurement values. Regularization using the preferred homogeneity condition attempts to minimize variation between values at pilot points within each hydrogeologic unit by penalizing deviations from “smoothness.” Finally, the compromise between model fit and the preferred condition was initially weighted in favor of model fit and later weighted to favor the preferred condition (PEST variable PHIMLIM). The Singular Value Decomposition-Assist (SVDA) method was used to reduce the number of estimated parameters, thereby speeding up the calibration process. For steady-state calibration the SVDA method identified 100 “super parameters” that are linear combinations of the original parameters and contribute most to changes (reductions) in the objective function; 30 super parameters were used for transient calibration because of the longer execution time for transient runs. The SVDA process calibrates to the best solution in terms of super parameters, and then assigns calibrated values to the original parameters. The advantage of SVDA is that fewer parameters (100 rather than 1,855 for the steady-state calibration) are required during model calibration so fewer model runs are needed, and the objective function converges more quickly. ---PAGE BREAK--- 20 Numerical Simulation of the Groundwater-Flow System in the Chambers-Clover Creek Watershed The model was calibrated for steady-state and transient conditions separately. The steady-state calibration resulted in estimates of parameter values for • Both horizontal and vertical hydraulic conductivity for each of the 10 hydrogeologic units at each of the pilot points, and estimates of parameter values for each active model cell; • River conductance in each of eight surface-water subbasins: Puyallup River; tributaries to Puyallup River; north Tacoma; Chambers–Clover Creek; American Lake–Murray Creek; Sequalitchew Creek; Nisqually River; tributaries to Nisqually River; • General Head Boundary conductance for each of the six hydrogeologic units that are in contact with Puget Sound (AL, B, C, D, E, and • Drain conductance for springs and seeps. The aquifer properties were allowed to vary during model calibration within two orders of magnitude above the initial specified value and within one order of magnitude below the initial specified value. The steady-state calibration used as observations (“calibration targets”) both the measured water- level altitudes from synoptic and monitoring wells (table 13, at end of report), as well as the estimated stream baseflow measurements (Savoca and others, 2010). Parameter value distributions from the steady-state PEST calibration were then used in the transient PEST calibration. The transient calibration allowed specific storage to vary within one order of magnitude above the initial specified value and within one order of magnitude below the initial specified value. After the transient calibration using PEST, the model was run again in the steady-state mode to generate subsequent steady-state model results. Calibration Data The groundwater-flow model was calibrated to groundwater-level and stream baseflow measurements. The steady-state calibration used the average values for these measurements, and the transient calibration used each of the water-level and baseflow measurements. Water- level measurements within the model domain from Savoca and others (2010) were used for calibration and include: water-level measurements for 124 monitoring wells wells) from March 2007–August 2008, and synoptic water-level measurements for 99 wells measured during September–December 2006. Pierce County Surface Water Management Division provided water-level measurements (January 2007–August 2008) for 4 monitoring wells (Rodney Gratzer, written commun., 2009) that also were used for calibration. A total of 2,355 groundwater-level measurements were used in the model calibration, including water levels that were influenced by conditions at the time of measurement (pumping, recovering, nearby pumping, nearby recovering, or flowing). Water-level measurements for each well were averaged to determine the steady-state calibration target value for that well. Groundwater levels, as depth below land surface, were converted to a water level altitude, according to the North American Vertical Datum of 1988, based on the LiDAR-derived land surface altitude at the location of the well. The average water levels for wells and the single water-level measurements for synoptic wells used during model calibration for each hydrogeologic unit are reported in table 13. Wells used to measure water levels were located within a model cell at a location given by the measured latitude and longitude of the well. The reported depth of the well screen and the well log were used to determine the model layer that represented the hydrogeologic unit screened by the well. Stream baseflow at 51 locations was measured during two synoptic streamflow measurements (September 2007 and July 2008) to identify gaining and losing reaches along segments of major streams in the model area. Stream baseflow measurement locations and discharge values used during calibration are given in Savoca and others (2010, pl. 1 and table 5, respectively). Stream baseflow measurements and estimates of stream gains and losses were used in the calibration process to assess whether the simulated pattern of gains and losses matched measured gains and losses. The estimates of stream gains and losses derived from stream baseflow measurements were compared with model‑derived gains and losses for each stream reach. Weights for Measured Quantities In PEST, weights are assumed to be proportional to the inverse of the standard deviation of measurement error (Doherty 2005; Hill and Tiedeman, 2007). Because measurement error was not well defined weights were assigned to calibration data (groundwater-level and stream baseflow) to reflect the approximate accuracy of each of the measurements. The weights (table 13) were assigned according to a relative scale from 1 to 10. For the steady- state calibration the most accurate measurements were assigned a weight of 10. Weights were reduced for less accurate measurements that were affected by conditions at the time of measurement (pumping, recovering, nearby pumping, nearby recovering, or flowing). Most wells with data had between 17 and 20 measurements; if the number of “most accurate” measurements associated with a well was between 10 and 15, the weight assigned to the average measurement was reduced to 9, if the number of “most accurate” measurements was less than 10, the weighting of the average was reduced to 8. Synoptic wells, with only one or two measurements, were assigned a default weight of 3, which was in some cases reduced to 2 or 1 if the measurement were “less accurate”. ---PAGE BREAK--- Numerical Simulation of the Groundwater-Flow System 21 For the transient calibration, each water-level measurement was included as a separate observation, with the most accurate measurements assigned a weight of 10. The weights were reduced for less accurate measurements that were impacted by conditions at the time of measurement as follows: 5 for flowing, 4 for nearby pumping or nearby recovering, and 3 for pumping or recovering. Transient calibration weights also were assigned to differences between water-level measurements used to represent seasonal water-level fluctuations in the model, and weighted according to the accuracy of the measurements. Estimates of stream baseflow were included in both steady-state and transient calibrations. The average of the two baseflow measurements (September 2007 and July 2008) at each baseflow location was used in the steady-state calibration; each of the two baseflow measurements was included as a separate observation for the transient calibration. These measurements were weighted according to the rankings assigned to each baseflow measurement (Savoca and others, 2010), and weighted with an additional factor of 0.0005 to account for different measurement units (cubic feet per day rather than feet used for the altitude of water-level measurements), and the greater uncertainty (standard deviation) associated with baseflow measurements. The different weighting factors used for water- level, water-level difference, and baseflow measurements also served to balance the contribution of each type of observation to the overall objective function, so that each would be considered in the calibration process (for example, the magnitude of the weighted residuals were similar for each type of observation). Table 13 shows the wells that were used for the calibration and their assigned steady state calibration weighting factors, the total number of transient observations, and the number of observations that were reduced on the basis of the status of the water-level reading. For the wells that were used for the transient calibration, the table shows the number of observations and the mean weighting factor for the observations in that well. The locations of the wells (as identified by the well map numbers in table 13) are shown in figure 7. Initial Conditions Initial conditions refer to the distribution of water levels in the groundwater system at the beginning of the transient calibration period (September 2006–August 2008). Initial conditions were established through transient simulation of a 3-year “lead-in” period (September 2003–August 2006). The lead-in period simulation is designed to isolate the transient calibration from potential inaccuracies associated with initial transient calibration start-up. Temporal discretization of the lead-in period comprised 36 transient stress periods in which specified recharge was based on measured precipitation. Well withdrawals (and return flows) were represented by adjusting withdrawal rates to reflect population change during the lead-in period. Temporal fluctuations in Puyallup and Nisqually River stage were obtained from USGS records, and temporal fluctuations in other model boundary conditions (other streams and lakes) were patterned after fluctuations delineated for the calibration period. Starting heads for the beginning of the lead-in period (September 1, 2003) were derived from early calibration transient output for September 1, 2008 to provide representative transient water-level conditions. Parameter Sensitivity Sensitivity is the relative effect that changes in an individual parameter value has on the overall objective function. Because SVDA and “super parameters” were used for both steady-state and transient calibration, sensitivities for the original PEST parameters were not determined during the calibration process itself. However, an additional PEST run was conducted after completion of the steady- state and transient calibration to determine sensitivities for all original PEST parameters. The composite sensitivities of the parameters to the overall objective function including head (water level), head difference, and stream-baseflow target values, are shown in figure 8. Horizontal and vertical hydraulic conductivity (Kh and Kv), and specific storage (and equivalent specific yield) parameter sensitivities were determined at 182 pilot point locations distributed throughout the model domain; figure 8 contains the median value of pilot point sensitivities for each conductivity and storage parameter by hydrogeologic unit. The wide range of sensitivities dictated that a logarithmic scale be used to represent sensitivity values. Because the objective function is nominally scaled by the weighting factors (as inverse standard deviations) and because the parameter changes are produced on a logarithmic (multiplicative factor) basis, the sensitivity can be considered non-dimensional. The values of insensitive parameters (such as vertical hydraulic conductivity in the A1 aquifer unit) remain largely unchanged during the PEST calibration process. Therefore, the insensitivity of these parameters places greater importance on the initial values assigned to them. Results from the steady-state sensitivity analysis (fig. 8A) indicate that the model is most sensitive to river conductance parameters Rv4 (conductance in Swan, Clear, and Clarks Creeks) and Rv6 (conductance in Chambers–Clover Creek), and less sensitive to Rv0 (American Lake–Murray Creek) and Rv2 (tributaries to Nisqually River). The least sensitive river conductance parameters (Rv3, Puyallup River and Rv7, North Tacoma) coincide with model areas containing fewer groundwater level and streamflow measurements. The model also is sensitive to values of horizontal hydraulic conductivity (Kh), particularly in aquifer units AL, A1, A3, and C. Sensitivities to vertical hydraulic conductivity (Kv) generally are much lower than corresponding horizontal hydraulic conductivity values, but are most significant in confining units A2 and B. The steady-state calibration is ---PAGE BREAK--- 22 Numerical Simulation of the Groundwater-Flow System in the Chambers-Clover Creek Watershed Figure 7. Locations of wells used in model calibration, Chambers-Clover Creek watershed and vicinity, Washington. R. 05 E. T. 15 N. T. 15 N. T. 17 N. T. 18 N. T. 19 N. T. 20 N. T. 21 N. R. 04 E. R. 03 E. R. 02 E. R. 01 E. Base from U.S. Geological Survey digital data, 1983, 1:100,000 Universal Transverse Mercator projection, Zone 10 Horizontal Datum: North American Datum of 1983 (NAD 83) 47°00° 46°50' 47°20' 30' 20' 122°10' 122°40' 10' 0 4 6 8 MILES 2 0 4 6 8 KILOMETERS 2 EXPLANATION Boundary of Water Resource Inventory Area Boundary of active model Location of wells with map no. (See table 13 for additional information) Symbol indicates hydrogeologic unit of well AL– Alluvial valley aquifer A1– Aquifer A3– Aquifer A2– Confining unit B– Confining unit D– Confining unit G– Undifferentiated deposits C– Aquifer E– Aquifer 1 2 5 7 4 9 6 8 11 13 21 14 19 73 10 12 29 27 16 34 15 17 38 18 40 20 52 24 59 55 22 57 56 32 66 65 23 41 25 62 37 60 26 31 28 72 43 49 51 68 35 30 71 39 44 53 33 36 48 64 61 42 74 47 63 75 50 46 69 45 81 54 58 76 78 67 70 90 77 89 85 86 91 80 97 96 98 79 84 87 82 88 93 92 94 95 83 99 178 156 164 168 154 104 108 115 122 101 124 103 117 116 118 119 109 129 136 137 143 138 139 140 134 133 106 102 105 159 112 127 123 145 113 110 147 100 158 114 148 149 121 120 132 107 135 111 126 128 142 150 131 130 125 151 179 157 144 155 141 187 169 146 162 166 167 153 152 160 175 161 163 165 170 171 182 176 173 172 183 177 180 181 199 174 188 186 185 189 192 193 184 196 190 195 194 191 201 203 206 202 209 198 208 204 200 197 207 212 211 213 205 210 214 220 217 222 216 223 215 221 219 218 224 225 226 227 228 ---PAGE BREAK--- Numerical Simulation of the Groundwater-Flow System 23 0.00001 0.0001 0.001 0.01 0.1 1 Steady-state sensitivity, as median value of pilot points F E D C B A3 A2 A1 AL G dr1 dr2 rv6 rv5 rv4 rv3 rv2 rv1 rv0 rv7 ghc F ghc E ghc D ghc C ghc B ghc AL Parameters Hydrogeologic unit Horizontal hydraulic conductivity (Kh) Vertical hydraulic conductivity (Kv) General head conductance Drain conductance River conductance EXPLANATION EXPLANATION A Figure 8. Sensitivity of the steady-state and transient calibrations to changes in parameter values, Chambers–Clover Creek watershed and vicinity, Washington. ---PAGE BREAK--- 24 Numerical Simulation of the Groundwater-Flow System in the Chambers-Clover Creek Watershed 0.0001 0.001 0.01 0.1 1 10 F E D C B A3 A2 A1 AL G dr1 dr2 rv6 rv5 rv4 rv3 rv2 rv1 rv0 rv7 ghc F ghc E ghc D ghc C ghc B ghc AL Parameters Transient sensitivity, as median value of pilot points Hydrogeologic unit Horizontal hydraulic conductivity (Kh) Vertical hydraulic conductivity (Kv) General head conductance Specific storage Drain conductance River conductance EXPLANATION EXPLANATION B Figure 8.—Continued ---PAGE BREAK--- Numerical Simulation of the Groundwater-Flow System 25 relatively less sensitive to general head (ghc) and drain (dr) conductance parameters. Results from the transient sensitivity analysis (fig. 8B) indicate that the model is most sensitive to river conductance parameters Rv4 (conductance in Swan, Clear, and Clarks Creeks), and Rv6 (conductance in Chambers–Clover Creek), and least sensitive to river conductance parameters Rv3 (Puyallup River), and Rv7 (North Tacoma). The model also is sensitive to values of: horizontal hydraulic conductivity (Kh), particularly in aquifer units AL, A1, and C, and the undifferentiated deposit (unit vertical hydraulic conductivity (Kv), particularly in confining units A2 and D; and spring (dr1) and seep (dr2) drain conductance values. The transient calibration is less sensitive to storage parameters and general head boundary conductances (ghc). Final Parameter Values Final parameter value distributions were determined from the steady-state and transient PEST calibration process for each model parameter. Final value distributions of horizontal conductivity (figs. 22A–J, at back of report), vertical hydraulic conductivity (figs. 22K–T, at back of report) and specific storage (figs. 22U–DD, at back of report) are summarized in table 5. Median calibrated horizontal hydraulic conductivity values in aquifer units (table 5) ranged from 21 ft/d in aquifer unit E to 153 ft/d in the A1 aquifer unit. Median calibrated horizontal hydraulic conductivity values in confining units ranged from 1.9 ft/d in the A2 and B units to 2.9 ft/d in the D and F confining units. The median calibrated horizontal hydraulic conductivity value of the undifferentiated deposit (unit G) was 4.0 ft/d. Median calibrated horizontal hydraulic conductivity values are lower than initial estimates (table but follow a similar pattern of higher conductivity values for aquifers and lower values for confining units (Savoca and others, 2010). Median calibrated vertical hydraulic conductivity values in aquifer units (table 5) ranged from 2.0 ft/d in aquifer units C and E to 10 ft/d in the A1 aquifer unit. Median calibrated vertical hydraulic conductivity values in confining units ranged from 0.017 ft/d in the B unit to 0.031 ft/d in confining unit D. The median calibrated vertical hydraulic conductivity value of the undifferentiated deposit (unit G) was 0.099 ft/d. Median calibrated vertical hydraulic conductivity values are lower than initial estimates (table but follow a similar pattern of higher conductivity values for aquifers and lower values for confining units (Savoca and others, 2010). Median calibrated specific-storage values for aquifer units (table 6) ranged from 1.44 × 10–6 ft–1 in aquifer unit E to 5.53 × 10–3 ft–1 in aquifer unit A1. Median calibrated specific storage values for confining units ranged from 5.52 × 10–6 ft–1 in the F unit to 2.74 × 10–5 ft–1 in confining unit B. The median calibrated specific storage value of the undifferentiated deposit (unit G) was 3.0 × 10–7 ft–1. Median calibrated specific storage values are lower than initial estimates (table 4) for units AL, A1, D, F, and G, and higher than initial estimates for units A2, A3, B, C, and E. Calibrated General Head Boundary conductance values (table 5) for each of the six hydrogeologic units that surface under Puget Sound (AL, B, C, D, E, and F) ranged from 3.30 × 10–4 ft2/d in unit B to 5.08 × 10–6 ft2/d in the AL aquifer unit. Calibrated General Head Boundary conductance values are lower than initial estimates (table The final calibrated distribution of riverbed conductance is shown in figure 9, and is summarized in table 5 for eight surface-water subbasins delineated in the model area. Median calibrated riverbed conductance values ranged from 1.9 ft2/d (Rv3) to 2.04 × 106 ft2/d (Rv0). Median calibrated riverbed conductance values are lower than initial estimates for subbasins Rv0, Rv2, Rv3, Rv5, and Rv7, and higher than initial estimates for subbasins Rv1, Rv4, and Rv6. The median calibrated drain conductance value for springs (Dr1) and seeps (Dr2) was 0.17 and 0.20 ft2/d, respectively (table Median calibrated drain conductance values are lower than initial estimates for both springs and seeps. Assessment of Steady-State Calibration The results of the steady-state calibration were assessed by comparing measured and simulated quantities (groundwater levels and stream baseflows) and by examining the mean and standard deviation of residuals (un-weighted), objective function, and root mean-square error (RMSE) of weighted residuals for average and individual synoptic groundwater levels, and average baseflow gains or losses. The mean of residuals represents the average difference between all measured and simulated values (residuals), and the sign of the mean of residuals (bias) indicates whether the model is over- or under-predicting values (negative and positive mean of residuals, respectively). The standard deviation of residuals is a measure of how much variation there is in residual values above and below the mean residual value. A low standard deviation indicates that the residuals tend to be very close to the mean, whereas high standard deviation indicates that residuals are spread out over a large range of values around the mean. The objective function represents the weighted total of all squared residuals, and the magnitude of the objective function is a measure of the cumulative difference between all measured and simulated values. The RMSE of weighted residuals provides a measure of variation that considers measurement accuracy. ---PAGE BREAK--- 26 Numerical Simulation of the Groundwater-Flow System in the Chambers-Clover Creek Watershed Table 5. Final parameter values and factors used in the steady-state and transient calibrations, Chambers-Clover Creek watershed and vicinity, Washington. [Abbreviations: Kh, horizontal hydraulic conductivity; Kv, vertical hydraulic conductivity; HGU, hydrogeologicl unit; GHB, general head boundary; ft, feet; ft/d, feet per day; 1/ft, per feet; ft2/d, square feet per day] Kh (ft/d) Hydro- geologic unit Median Mini- mum Maxi- mum Change from initial estimate AL 42 3.28 3,280 × 0.13 A1 153 9.33 9,330 × 0.16 A2 1.9 0.18 180 × 0.10 A3 85 5.88 5,880 × 0.15 B 1.9 0.21 12 × 0.09 C 32 0.60 9,913 × 0.16 D 2.9 0.29 107 × 0.10 E 21 2.14 2,140 × 0.10 F 2.9 1.31 14 × 0.10 G 4.0 0.39 450 × 0.10 Kv (ft/d) Median Mini- mum Maxi- mum Change from initial estimate 3.1 0.328 328 × 0.093 10 8.33 54 × 0.108 0.022 0.002 1.8 × 0.110 6.0 0.588 19 × 0.102 0.017 0.002 2.1 × 0.083 2.0 0.198 198 × 0.102 0.031 0.003 2.9 × 0.103 2.0 0.393 3.5 × 0.095 0.030 0.013 0.136 × 0.099 0.099 0.013 0.587 × 0.076 Specific storage (1/ft) Median Mini- mum Maxi- mum Change from initial estimate 1.90E-03 1.00E-03 1.00E-01 × 0.190 5.53E-03 1.00E-03 1.00E-01 × 0.553 1.40E-05 1.00E-06 1.00E-04 × 1.40 2.48E-06 1.00E-07 1.00E-05 × 2.48 2.74E-05 1.00E-06 1.00E-04 × 2.74 1.74E-06 1.00E-07 1.00E-05 × 1.74 6.09E-06 1.00E-06 1.00E-04 × 0.609 1.44E-06 1.00E-07 1.00E-05 × 1.44 5.52E-06 1.00E-06 1.00E-04 × 0.552 3.00E-07 3.00E-07 3.00E-05 × 0.100 GHB conductance (ft2/d) GHB- parameter group Final conduc- tance (ft2/d) Change from initial estimate ghcAL 5.08E6 × 0.153 ghcB 3.30E4 × 0.166 ghcC 2.06E6 × 0.103 ghcD 4.11E4 × 0.137 ghcE 2.16E6 × 0.103 ghcF 3.63E4 × 0.121 River conductance River parameter group Sub-basin Median cell value (ft2/d) Minimum cell value (ft2/d) Maximum cell value (ft2/d) Change from initial estimate Rv0 American Lake- Murray Creek 2.04E6 2,392 5.36E6 × 0.53 Rv1 Nisqually River 2.96E5 555 1.29E6 × 25.2 Rv2 Tributaries to Nisqually River 22 0.021 16,603 × 1.60E–3 Rv3 Puyallup River 1.9 0.009 3.6 × 1.70E–4 Rv4 Tributaries to Puyallup River 4.10E5 1,540 2.29E8 × 73.4 Rv5 Sequalitchew Creek 917 115 4.48E5 × 0.051 Rv6 Chambers-Clover Creek 8.05E4 86 5.72E7 × 5.04 Rv7 North Tacoma 30 0.043 44 × 3.10E–3 Drain conductance Drain parameter group Drain feature Median cell value (ft2/d) Mini- mum cell value (ft2/d) Maxi- mum cell value (ft2d) Change from initial estimate Dr1 Springs 0.17 0.003 10 × 1.70E–3 Dr2 Seeps 0.20 0.038 1.4 × 2.88E–5 ---PAGE BREAK--- Numerical Simulation of the Groundwater-Flow System 27 R. 05 E. T. 15 N. T. 15 N. T. 17 N. T. 18 N. T. 19 N. T. 20 N. T. 21 N. R. 04 E. R. 03 E. R. 02 E. R. 01 E. Puget Sound Lake Tapps American Lake Gravelly Lake Spanaway Lake Steilacoom Lake Ohop Lake Tanwax Lake Lake Kapowsin Swan Creek Puya llu p River C l o ver C re e k C h a m bers C r ee k Nis q ual l y R iv er N i s q u a l l y Riv e r P u y a ll u p R i v e r C a r b o n R i v e r M a s h e l Ri ver M u c k C r e e k M u c k C re e k L acam a s C r e ek C l e a r C r e ek C la r k s Cr e ek P u allup R iv er C lo v e r C r e ek S ou t h C re ek T a nwa x C re ek S e q ua l i tc he w C r . M u r r ay C r e e k N. Fork C . C. Base from U.S. Geological Survey digital data, 1983, 1:100,000 Universal Transverse Mercator projection, Zone 10 Horizontal Datum: North American Datum of 1983 (NAD 83) 47°00° 46°50' 47°20' 30' 20' 122°10' 122°40' 10' 0 4 6 8 MILES 2 0 4 6 8 KILOMETERS 2 0.01 to 1 1.01 to 100.00 100.01 to 10,000.00 10,000.01 to 1,000,000.00 1,000,000.01 to 228,600,000.00 EXPLANATION Boundary of Water Resource Inventory Area Boundary of active model Conductances for river boundary conditions, in square feet per day Rv1–Nisqually River Rv2–Tributaries to Nisqually River Rv3–Puallup River Rv4–Tributaries to Puallup River Rv5–Sequalichew Creek Rv6–Chambers - Clover Creek Rv7–North Tacoma Rv0–American Lake– Murray Creek Spatial extent of subbasins Rv1 Rv2 Rv3 Rv4 Rv6 Rv0 Rv5 Rv7 Figure 9. Final parameter value distribution of river conductance (Puyallup River; tributaries to Puyallup River; north Tacoma; Chambers-Clover Creek; Murray Creek-American Lake; Sequalitchew Creek; Nisqually River; tributaries to Nisqually River), Chambers-Clover Creek watershed and vicinity, Washington. ---PAGE BREAK--- 28 Numerical Simulation of the Groundwater-Flow System in the Chambers-Clover Creek Watershed Table 6 shows the steady-state calibration statistics for groundwater-levels (by hydrogeologic unit) and stream baseflow gains or losses. Calibration statistics were used to evaluate how well the model simulates measured values (fit). The best fit for simulated and measured groundwater-level values based on RMSE occurred in hydrogeologic units D, AL, and G; the worst fit occurred in hydrogeologic units A3, E, and A2. Hydrogeologic units A3, A1, and G had the lowest absolute value of mean residuals, indicating simulated groundwater-levels in these units had the lowest model bias. The final steady-state calibration has an RMSE for all groundwater levels and stream baseflows of 24.29 ft and 1.82 ft3/s, respectively. Given that the total range of average measured groundwater levels is about 843 ft (853.61 ft in well #154 – 10.95 ft in well an RMSE of 24.29 ft is about 3 percent of the total range. Similarly, the range of average stream baseflow measurements is 63.5 ft3/s (55 ft3/s gaining at seepage run location 12102010 – losing 8.5 ft3/s at gage 12102075) and an RMSE of 1.82 is about 3 percent of the total range. A plot of measured versus simulated groundwater-level altitudes by hydrogeologic unit (fig.10) provides a useful graphical assessment of model calibration. Measured versus simulated values should plot close to a line with a slope equal to 1.0 and an intercept of zero. This diagonal line represents perfect agreement between measured and simulated values (the line of equal measured and simulated values), and the magnitude of the residual (difference between measured and simulated values) is reflected in the distance of the value above or below the line. Positive residuals (measured value is greater than simulated) and negative residuals (measured value is less than simulated) plot below and above the line, respectively. Measured versus simulated values shown in figure 10 generally fall along the line of equal measured and simulated values. The magnitude and sign of residuals for selected hydrogeologic units is discussed later in this section of the report. Table 6. Calibration statistics for the steady-state calibration by hydrogeologic unit and baseflow, Chambers-Clover Creek watershed and vicinity, Washington. [Root mean-square error of weighted residuals is calculated by dividing the sum of squared weighted residuals by the sum of squared weighting factors, then taking the square root. Abbreviations: ft, feet; ft2, square feet; NA, not applicable] Hydrogeologic unit observation group Count of observations Mean of unweighted residuals (ft) Standard deviation of unweighted residuals (ft) Sum of squared weighting factors Objective function (sum of squared weighted residuals) (ft2) Root mean- square error of weighted residuals (ft) Heads in AL 26 -5.66 9.71 793 89,174 10.60 Heads in A1 26 -3.84 19.92 1,778 263,500 12.17 Heads in A2 14 7.40 26.17 909 628,905 26.30 Heads in A3 84 0.80 38.09 4,471 5,075,077 33.69 Heads in B 3 16.19 13.70 281 114,667 20.20 Heads in C 61 -9.20 20.85 3,847 850,320 14.87 Heads in D 1 -6.43 NA 100 4,130 6.43 Heads in E 9 5.17 29.83 655 681,665 32.26 Heads in G 3 -4.44 13.72 300 43,534 12.05 Total: All heads 227 -2.48 28.42 13,134 7,750,974 24.29 Baseflow gain or loss observation group 50 0.23 (ft3/s) 2.12 (ft3/s) 6.53×10–4 16,137,000 (ft3/d)2 or 2.16 × 10-3 (ft3/s)2 1.82 (ft3/s) ---PAGE BREAK--- Numerical Simulation of the Groundwater-Flow System 29 0 100 200 300 400 500 600 700 800 0 100 200 300 400 500 600 700 800 900 Simulated steady-state groundwater altitude, in feet above NAVD 88 Average of measured groundwater altitude, in feet above NAVD 88 AL– Alluvial valley aquifer A1– Aquifer A3– Aquifer A2– Confining unit B– Confining unit D– Confining unit G– Undifferentiated deposits C– Aquifer E– Aquifer EXPLANATION Figure 10. Simulated and average measured water-level altitudes for the steady-state calibration, Chambers-Clover Creek watershed and vicinity, Washington. ---PAGE BREAK--- 30 Numerical Simulation of the Groundwater-Flow System in the Chambers-Clover Creek Watershed The results of the steady-state calibration also were evaluated by displaying the simulated water levels (heads) in each model cell for aquifer units and G undifferentiated deposits (figs. 23A–F, at back of report). The residuals (measured target value minus model‑simulated value in that well) for each of the and synoptic wells screened in the hydrogeologic unit are posted at well locations. Simulated steady-state groundwater-level altitudes and flow directions (figs. 23A–F) agree generally with groundwater conditions observed by Savoca and others (2010, figs. 16–21). Simulated steady-state groundwater-level altitudes in the AL alluvial valley aquifer beneath the Puyallup River valley (fig.23A) indicate flow generally moving in a northwesterly down-valley direction towards Puget Sound. Maximum positive and negative groundwater-level altitude residuals in the AL alluvial valley aquifer beneath the Puyallup River valley are 18 and -26 ft, respectively. Simulated groundwater- level altitudes in the AL alluvial valley aquifer beneath the Nisqually River valley (fig. 23A) also indicate flow generally moving in a northwesterly down-valley direction towards Puget Sound. No data were collected from the aquifer in this area (Savoca and others 2010), therefore residuals were not computed. Simulated groundwater-level altitudes in the A1 and A3 aquifers (figs. 23B and 23C, respectively) indicate flow generally moving in a northwesterly direction towards Puget Sound. Simulated groundwater-level altitudes also indicate northeast and westward flows toward the Puyallup and Nisqually River valleys, respectively. Maximum positive and negative groundwater-level altitude residuals in the A1 aquifer are 64 and -37 ft, respectively, and in the A3 aquifer are 180 and -111 ft, respectively. Simulated groundwater-level altitudes in the C and E aquifers (figs. 23D and 23E, respectively) indicate flow generally moving in a northwesterly direction towards Puget Sound. Simulated groundwater-level altitudes also indicate northeast and westward flows toward the Puyallup and Nisqually River valleys, respectively. Maximum positive and negative groundwater-level altitude residuals in the C aquifer are 61 and -87 ft, respectively, and in the E aquifer are 72 and -28 ft, respectively. Simulated groundwater-level altitudes in the G undifferentiated deposits (fig. 23F) indicate flow generally moving in a northwesterly direction towards Puget Sound. Simulated groundwater-level altitudes also indicate northeast and westward flows toward the Puyallup and Nisqually River valleys, respectively. Maximum positive and negative groundwater-level altitude residuals in the G undifferentiated deposits are 11 and -15 ft, respectively The steady-state calibration also was evaluated for how well it simulated flow out of the model through boundary conditions. A water budget for the steady-state calibration is presented in section, “Model-Derived Groundwater Budget,” as calculated by the MODFLOW utility Zonebudget (Harbaugh, 2000). Groundwater recharge and well withdrawals were determined outside the model and were assigned fixed values as model input; groundwater discharge to rivers, lakes, and springs, and flow out of the model to Puget Sound were simulated in the model according to head- dependent boundary conditions. A comparison of the measured and simulated groundwater discharge to streams (baseflow) in the model area was based on synoptic stream baseflow measurements conducted in September 2007 and July 2008 (Savoca and others, 2010). Time-averaged stream gain and loss values derived from baseflow measurements from 51 measurement sites (Savoca and others, 2010, pl. 1 and table 5) were compared to simulated stream gain and loss values derived from simulated groundwater discharge to streams at the same locations (fig. 11). Stream gains and losses are reasonably well simulated by the steady-state calibration, however, there are a few locations in the Chambers-Clover Creek Watershed (WRIA12) where the model simulates a net loss of streamflow but small net gains in streamflow were measured during synoptic stream baseflow measurements (Savoca and others, 2010). There also is one location in the Puyallup River Watershed (WRIA 10) where the model simulates a net gain of streamflow but a small net loss in streamflow was measured during synoptic stream baseflow measurements (Savoca and others, 2010). ---PAGE BREAK--- Numerical Simulation of the Groundwater-Flow System 31 Figure 11. Simulated and average measured stream baseflows for the calibrated model for steady-state conditions, Chambers–Clover Creek watershed and vicinity, Washington. -10 0 10 20 30 40 50 60 70 -20 -10 0 10 20 30 40 50 60 Gaining Losing Losing Gaining WRIA 12 WRIA 10 WRIA 11 EXPLANATION Simulated steady-state baseflow gains or losses, in cubic feet per second (ft3/s) Average of measured baseflow gains or losses, in cubic feet per second (ft3/s) ---PAGE BREAK--- 32 Numerical Simulation of the Groundwater-Flow System in the Chambers-Clover Creek Watershed Assessment of Transient Calibration The results of the transient calibration were assessed by comparing measured and simulated quantities (groundwater levels and stream baseflows) and by examining the mean and standard deviation of residuals (un-weighted), objective function, and RMSE of weighted residuals for: all individual synoptic and groundwater-level measurements; groundwater-level differences to represent seasonal water-level fluctuations above and below the initial groundwater-level measurement for each well; and baseflow gains or losses for September 2007 and July 2008 (table The best fit between simulated and measured groundwater-level head values based on RMSE occurred in hydrogeologic units D, AL, and A1; the worst fit occurred in hydrogeologic units E, A3, and A2. These same units were among the best and worst fit, respectively, for simulated and measured groundwater-level head difference values based on RMSE. Hydrogeologic units AL, A1, A3, and E had the lowest absolute value of mean head and head difference residuals, indicating simulated groundwater-levels in these units had the lowest model bias. The final transient calibration has an RMSE for all groundwater-level head, head difference, and stream baseflows of 22.59 ft, 5.82 ft, and -2.51 ft3/s, respectively. Given the total range of measured values for these observation groups (851.5 ft, 135.5 ft, and 68.4 ft3/s), the RMSE for head, head difference, and stream baseflows are 2.7, 4.3, and 3.7 percent of the total range. Table 7. Calibration statistics for the transient calibration by hydrogeologic unit and baseflow, Chambers-Clover Creek watershed and vicinity, Washington. [Root mean-square error of weighted residuals is calculated by dividing the sum of squared weighted residuals by the sum of squared weighting factors, then taking the square root. Abbreviations: ft, feet; ft2, square feet; ft3/s, cubic feet per second] Hydrogeologic unit observation group Count of observations Mean of unweighted residuals (ft) Standard deviation of unweighted residuals (ft) Sum of squared weighting factors Objective function (sum of squared weighted residuals) (ft2) Root mean-squared error of weighted residuals (ft) Heads in AL 138 -2.34 10.13 12,134 1,065,153 9.37 Heads in A1 323 0.44 11.15 31,663 3,983,952 11.22 Heads in A2 169 10.96 25.09 12,872 10,043,721 27.93 Heads in A3 787 1.60 31.22 72,787 66,633,173 30.26 Heads in B 50 16.56 11.86 4,545 2,038,732 21.18 Heads in C 705 -4.36 13.32 64,206 12,671,574 14.05 Heads in D 18 -5.97 1.85 1,800 69,977 6.24 Heads in E 112 14.95 30.97 10,745 12,998,208 34.78 Heads in G 53 -2.76 12.04 5,300 794,085 12.24 Total: All heads 2,355 0.90 23.01 216,052 110,298,574 22.59 Head differences in AL 112 -0.37 1.23 1,200,925 2,224,021 1.36 Head differences in A1 297 0.23 2.84 3,507,313 23,194,476 2.57 Head differences in A2 155 0.81 6.88 1,420,850 74,552,544 7.24 Head differences in A3 703 -2.01 7.85 7,902,253 333,801,660 6.50 Head differences in B 47 -1.56 5.34 516,200 5,571,155 3.29 Head differences in C 644 0.82 6.77 7,058,931 296,428,333 6.48 Head differences in D 17 -0.71 1.89 205,700 797,886 1.97 Head differences in E 103 -0.47 6.44 1,204,300 51,526,875 6.54 Head differences in G 50 0.50 4.31 605,000 11,183,625 4.30 Total: All head differences 2,128 -0.39 6.59 23,621,472 799,280,575 5.82 Baseflow gain or loss observation group 96 -0.36 (ft3/s) 2.67 (ft3/s) 1.16 × 10–3 54,297,883 (ft3/s) or 7.27 × 10–3(ft3/s) -2.51 (ft3/s) ---PAGE BREAK--- Numerical Simulation of the Groundwater-Flow System 33 A plot of average measured versus average simulated groundwater-level altitudes values for the transient simulation period (September 2006–August 2008) by hydrogeologic unit (figure 12) generally fall along the line of equal measured and simulated values (slope equal to 1.0, intercept of zero). The magnitude of the residual (difference between measured and simulated values) is reflected in the distance of the value above or below the line. Positive residuals (measured value is greater than simulated value) and negative residuals (measured value is less than simulated) plot below and above the line, respectively. The results of the transient calibration were evaluated by comparing measured and simulated groundwater-level hydrographs for selected wells (fig. 13). Measured water levels generally fluctuate in response to seasonal changes in recharge. Simulated water levels also fluctuate in response to seasonal variation in recharge and, in most cases, the magnitude and timing of these fluctuations are similar to the changes in measured water levels. The transient calibration also was evaluated for how well it simulated groundwater discharge to streams during baseflow conditions. Stream gain and loss values derived from baseflow measurements conducted in September 2007 and July 2008 at 51 measurements sites (Savoca and others, 2010, pl. 1 and table 5) were compared to simulated stream gain and loss values derived from simulated groundwater discharge to streams at the same locations and times of year (fig. 14). Stream gains and losses are reasonably well simulated by the transient calibration, however, there are a few instances where the model simulates a net loss of streamflow but small net gains in streamflow were measured during synoptic stream baseflow measurements (Savoca and others, 2010). There also are a few instances where the model simulates a net gain of streamflow but small to moderate net losses in streamflow were measured during synoptic stream baseflow measurements (Savoca and others, 2010). Model Limitations The model presented in this report is a simplified mathematical representation of the complex natural groundwater-flow system in the CCCW and vicinity. Intrinsic to the model is the error and uncertainty associated with the approximations, assumptions, and simplifications that must be made. Although the model provides a relatively good fit between simulated and measured quantities, indicating that the overall simulated groundwater flow is a reasonable representation of groundwater flow in the CCCW and vicinity, the model is subject to limitations. In general, because of model scale and level of detail, the model is most applicable to analysis of groundwater issues at the subbasin scale (see fig. Local‑scale heterogeneity in hydrologic properties, recharge, and discharge that occur at a scale of one model cell or less (1,000 ft or less) are not adequately represented by the regional-scale groundwater-flow model constructed for this study. The data used to construct and calibrate the model reflect short-term conditions (September 2006–August 2008) and probably do not represent the full range of hydrologic and anthropogenic variability within the system. Boundary conditions and the representation of various components of the flow system that were appropriate for the calibrated range of conditions may be inappropriate for model simulations when conditions in the groundwater system are beyond the range used during calibration. There is no long-term ambient groundwater monitoring network in the model area, and data from the short-term (March 2007–September 2008) monitoring network established for this study (Justin and others, 2009) are insufficient to evaluate water-level trends relating to long-term changes in groundwater storage, or for testing the assumption of steady-state conditions. Measurement-based estimates of recharge were not available for the model area. The distribution of recharge from precipitation in the model area was estimated by applying regional precipitation–recharge relations based on regression equations for unconsolidated glacial deposits in other areas of Puget Sound. The lack of available Group B public supply, residential, and crop irrigation well withdrawal data (few wells have flow gages installed or read) required the use of per-capita and crop irrigation requirement water-use estimates. Uncertainty also exists regarding estimates of residential return flows to the aquifer through septic system drain fields, and through outdoor (irrigation) use. Model Applications The calibrated model was used to derive components of the groundwater budget and to estimate the response of the regional system to new stresses, such as increased groundwater withdrawals. Water-resource managers can use this information to make informed decisions when planning for future groundwater development. The uncertainty associated with inaccuracies in the groundwater-flow model is carried forward to the model applications. ---PAGE BREAK--- 34 Numerical Simulation of the Groundwater-Flow System in the Chambers-Clover Creek Watershed Figure 12. Average simulated and average measured water-level altitudes for the calibrated model for transient conditions, Chambers-Clover Creek watershed and vicinity, Washington. AL– Alluvial valley aquifer A1– Aquifer A3– Aquifer A2– Confining unit B– Confining unit D– Confining unit G– Undifferentiated deposits C– Aquifer E– Aquifer EXPLANATION 0 100 200 300 400 500 600 700 800 0 100 200 300 400 500 600 700 800 900 Average of simulated transient groundwater altitude, in feet above NAVD 88 Average of measured groundwater altitude, in feet above NAVD 88 ---PAGE BREAK--- Numerical Simulation of the Groundwater-Flow System 35 Map index no. 107, AL Aquifer Map index no. 108, A1 Aquifer Map index no. 26, AL Aquifer Map index no. 217, A1 Aquifer Map index no. 73, AL Aquifer Map index no. 71, A1 Aquifer Map index no. 4, AL Aquifer Map index no. 175, A1 Aquifer J 2006 2007 2008 M A M F J D N O S A J J M A M F J D N O S A J S A J J 2006 2007 2008 M A M F J D N O S A J J M A M F J D N O S A J S A J J 2006 2007 2008 M A M F J D N O S A J J M A M F J D N O S A J S A J J 2006 2007 2008 M A M F J D N O S A J J M A M F J D N O S A J S A J J 2006 2007 2008 M A M F J D N O S A J J M A M F J D N O S A J S A J J 2006 2007 2008 M A M F J D N O S A J J M A M F J D N O S A J S A J J 2006 2007 2008 M A M F J D N O S A J J M A M F J D N O S A J S A J J 2006 2007 2008 M A M F J D N O S A J J M A M F J D N O S A J S A J 30 35 40 45 50 55 60 250 255 260 265 270 275 280 160 165 170 175 180 185 190 480 485 490 495 500 505 510 220 225 230 235 240 245 250 0 5 10 15 20 25 30 380 385 390 395 400 405 410 100 105 110 115 120 125 130 Observed EXPLANATION Simulated Altitude of groundwater level, in feet above NAVD 88 Altitude of groundwater level, in feet above NAVD 88 Figure 13. Simulated and measured groundwater levels for the calibrated model for transient conditions, Chambers–Clover Creek watershed and vicinity, Washington. ---PAGE BREAK--- 36 Numerical Simulation of the Groundwater-Flow System in the Chambers-Clover Creek Watershed Map index no. 109, A3 Aquifer Map index no. 211, A3 Aquifer Map index no. 202, A2 Confining Unit Map index no. 133, B Confining Unit Map index no. 86, A3 Aquifer Map index no. 110, A3 Aquifer Map index no. 167, A2 Confining Unit Map index no. 90, B Confining Unit J 2006 2007 2008 M A M F J D N O S A J J M A M F J D N O S A J S A J J 2006 2007 2008 M A M F J D N O S A J J M A M F J D N O S A J S A J J 2006 2007 2008 M A M F J D N O S A J J M A M F J D N O S A J S A J J 2006 2007 2008 M A M F J D N O S A J J M A M F J D N O S A J S A J J 2006 2007 2008 M A M F J D N O S A J J M A M F J D N O S A J S A J J 2006 2007 2008 M A M F J D N O S A J J M A M F J D N O S A J S A J J 2006 2007 2008 M A M F J D N O S A J J M A M F J D N O S A J S A J J 2006 2007 2008 M A M F J D N O S A J J M A M F J D N O S A J S A J 285 290 295 300 305 310 315 350 355 360 365 370 375 380 210 215 220 225 230 235 240 250 255 260 265 270 275 280 30 35 40 45 50 55 60 400 405 410 415 420 425 430 400 405 410 415 420 425 430 175 185 195 205 215 225 235 Observed EXPLANATION Simulated Altitude of groundwater level, in feet above NAVD 88 Altitude of groundwater level, in feet above NAVD 88 Figure 13.—Continued. ---PAGE BREAK--- Numerical Simulation of the Groundwater-Flow System 37 Map index no. 186, C Aquifer Map index no. 59, E Aquifer Map index no. 129, C Aquifer Map index no. 75, E Aquifer Map index no. 143, C Aquifer Map index no. 12, D Confining Unit Map index no. 115, C Aquifer Map index no. 62, E Aquifer J 2006 2007 2008 M A M F J D N O S A J J M A M F J D N O S A J S A J J 2006 2007 2008 M A M F J D N O S A J J M A M F J D N O S A J S A J J 2006 2007 2008 M A M F J D N O S A J J M A M F J D N O S A J S A J J 2006 2007 2008 M A M F J D N O S A J J M A M F J D N O S A J S A J J 2006 2007 2008 M A M F J D N O S A J J M A M F J D N O S A J S A J J 2006 2007 2008 M A M F J D N O S A J J M A M F J D N O S A J S A J J 2006 2007 2008 M A M F J D N O S A J J M A M F J D N O S A J S A J J 2006 2007 2008 M A M F J D N O S A J J M A M F J D N O S A J S A J 440 445 450 455 460 465 470 70 75 80 85 90 95 100 160 165 170 175 180 185 190 120 100 130 140 150 160 170 180 65 70 75 80 85 90 95 50 55 60 65 70 75 80 230 235 240 245 250 255 260 110 115 120 125 130 135 140 Observed Simulated EXPLANATION Altitude of groundwater level, in feet above NAVD 88 Altitude of groundwater level, in feet above NAVD 88 Figure 13.—Continued. ---PAGE BREAK--- 38 Numerical Simulation of the Groundwater-Flow System in the Chambers-Clover Creek Watershed Map index no. 74, G Undifferentiated Deposits Map index no. 85, G Undifferentiated Deposits Map index no. 96, E Aquifer J 2006 2007 2008 M A M F J D N O S A J J M A M F J D N O S A J S A J J 2006 2007 2008 M A M F J D N O S A J J M A M F J D N O S A J S A J J 2006 2007 2008 M A M F J D N O S A J J M A M F J D N O S A J S A J 170 175 180 185 190 195 200 225 230 235 240 245 250 255 245 250 255 260 265 270 275 Observed EXPLANATION Simulated Altitude of groundwater level, in feet above NAVD 88 Figure 13.—Continued. ---PAGE BREAK--- Numerical Simulation of the Groundwater-Flow System 39 -10 0 10 20 30 40 50 60 70 Simulated transient baseflow gains or losses, in cubic feet per second (ft3/s) Measured baseflow gains or losses, in cubic feet per second (ft3/s) Gaining Losing Losing Gaining -20 -10 0 10 20 30 40 50 60 WRIA 12 WRIA 12 WRIA 10 WRIA 10 WRIA 11 WRIA 11 Sept. 2007 EXPLANATION July 2008 Figure 14. Simulated and measured stream baseflows for the transient calibration, Chambers–Clover Creek watershed and vicinity, Washington. ---PAGE BREAK--- 40 Numerical Simulation of the Groundwater-Flow System in the Chambers-Clover Creek Watershed Model-Derived Groundwater Budget A groundwater budget for average conditions during the study period (September 1, 2006–August 31, 2008) in the model area is expressed by the following equation: , where is groundwater inflow to the model area, is groundwater outflow from the model area, is recharge, is discharge, and is change in groundwater storage. in out in out GW R GW D S GW GW R D S + = + + ∆ ∆ Recharge to the groundwater system occurs primarily as precipitation and seepage from streams and lakes. Secondary recharge (return flow) occurs as seepage from septic systems, deep percolation of irrigation water, and public water system conveyance losses. Discharge from the groundwater system occurs as seepage to streams and lakes, and groundwater seepage along bluffs adjacent to the Puyallup and Nisqually River valleys and bluffs along Puget Sound, as evaporation of groundwater from soils and transpiration from plants, as submarine seepage to Puget Sound, and as withdrawals from wells. A more detailed representation of the groundwater budget of the model area is provided by the equation: sec sec , where is recharge from precipitation, is recharge from streams, lakes, and Puget Sound, is secondary recharge, is groundwater discharge to streams, l in ppt sw out sw et ppg ppt sw sw GW R R R GW D D D S R R R D + + + = + + + + ∆ akes, springs, seeps, and Puget Sound, is groundwater discharge by evapotranspiration, and is groundwater withdrawal from wells. et ppg D D All water-budget components can be quantified on the basis of the steady-state calibration except discharge by evapotranspiration and change in groundwater storage. Net recharge was used; therefore, water lost to the system through direct evapotranspiration of groundwater is largely taken into account, and Det is not calculated in the model. Inflow to the system is assumed to be equal to outflow from the system under steady‑state conditions, resulting in no change in the volume of water stored within the system (ΔS = Substituting the calibrated-model values and above assumptions into equation 6 yields the following: In Rate (acre-ft/yr) Out Rate (acre-ft/yr) GWin 0 GWout 0 Rppt 465,567 Dsw 559,192 Rsw 129,778 Det Not calculated in model Rsec 11,699 Dppg 47,863 Total In 607,044 Total Out 607,055 The calibrated steady-state groundwater model budget can be used to make general observations about the flow system. Total flow through the groundwater system was about 607,050 acre-ft/yr in the model area. Precipitation was the primary source of water recharging the groundwater system (77 percent); recharge from streams and lakes (and a minor amount from Puget Sound) was 21 percent of the total recharge. Groundwater discharge to streams, lakes, springs, seeps, and Puget Sound was 559,192 acre-ft/yr, or 92 percent of the total discharge from the groundwater system. Withdrawals from wells were about 8 percent of discharge. The model-derived groundwater budget indicates no groundwater inflow to (GWin) or outflow from (GWout) the model area. This is due to the presence of regional-scale boundary conditions for the model, such as Puget Sound, the Puyallup and Nisqually River valleys, and an implicit no-flow boundary that coincides with the top of bedrock. These boundary conditions simulate the exchange of groundwater with surface-water features (Rsw and Dsw), and preclude the exchange of groundwater (no-flow boundary). Boundary conditions are approximate descriptions of complex natural systems, and it is likely that in places, groundwater flow occurs across major river valleys and bedrock contacts. ---PAGE BREAK--- Numerical Simulation of the Groundwater-Flow System 41 Savoca and others (2010) reported an estimated total groundwater discharge from the water-budget area of 455,000 acre-ft/yr. About one-half of this discharge (49 percent) was estimated to flow out of the CCCW and vicinity as submarine seepage to Puget Sound and as groundwater discharge to the Puyallup and Nisqually Rivers (224,700 acre-ft/yr), and 38 percent (171,800 acre-ft/yr) was estimated to flow to streams and springs. Model-derived groundwater flows for the CCCW and vicinity (table 8) indicate a total groundwater discharge of 476,777 acre-ft/yr. More than one-half of this simulated groundwater discharge (69 percent) flows out of the CCCW and vicinity as submarine seepage to Puget Sound and as groundwater discharge to the Puyallup and Nisqually Rivers (330,573 acre-ft/yr), and 21 percent (98,341 acre-ft/yr) flows to streams, lakes, and springs. Model-derived groundwater flows are considered reasonable when compared to estimates from Savoca and others (2010). The water budget for the transient simulation period (September 2006–August 2008) is presented in section, “Model Simulations for Six Scenarios. The budget indicates a change in groundwater storage of 11,392 acre-ft/yr during the transient simulation period, or about 2 percent of the precipitation recharge. This change in storage suggests that “true” steady-state conditions may not have been reached during steady-state calibration. However, there is no long- term ambient groundwater monitoring network in the model area, and data from the short-term (March 2007–September 2008) monitoring network established for this study (fig. 13) are insufficient to evaluate water-level trends relating to long-term changes in groundwater storage. Table 8. Model-derived groundwater flow, Chambers-Clover Creek watershed and vicinity, Washington. [Net flows equal inflow minus outflow; negative flows are out of the groundwater system or out of the WRIA. Column entries may not add exactly due to rounding. Abbreviation: acre-ft/yr, acre-feet per year; WRIA, water resources inventory area; NA, not applicable] Net flows (acre-ft/yr) WRIA 12 WRIA 10 WRIA 11 All WRIAs Recharge (precipitation and return flows) 178,080 82,451 216,240 476,772 Withdrawals from wells -32,909 -10,840 -4,114 -47,863 Puyallup and Nisqually Rivers 0 -127 -149,032 -149,159 Streams and Lakes -17,281 -75,708 -5,307 -98,296 Springs and Seeps -27 -11 -7 -45 Puget Sound -108,460 -50,463 -22,491 -181,414 Flow between WRIAs -19,389 54,681 -35,292 NA To WRIA 12 NA 56,546 -37,157 NA To WRIA 10 -56,546 NA 1,865 NA To WRIA 11 37,157 -1,865 NA NA ---PAGE BREAK--- 42 Numerical Simulation of the Groundwater-Flow System in the Chambers-Clover Creek Watershed Table 9. Comparison of selected water budget components for the “base simulation” steady- state condition and simulation 1. [Net flows equal inflow minus outflow; negative flows are out of the groundwater system or out of the WRIA. Column entries may not add exactly due to rounding. Abbreviations: acre-ft/yr, acre-feet per year; WRIA, water resources inventory area; NA, not applicable] Chambers-Clover Creek (WRIA12) Base simulation (acre-ft/yr) Simulation 1 (acre-ft/yr) Change (acre-ft/yr) Percent of change in recharge Recharge from precipitation 171,976 137,581 -34,395 NA Return flows 6,100 6,100 0 NA Withdrawals from wells -32,909 -32,909 0 NA Consumptive use -26,809 -26,809 0 NA Change in recharge NA NA -34,395 100 Streams and Lakes -17,281 +23,009 +40,290 +117 Springs and Seeps -27 -22 +5 0 Puget Sound -108,460 -104,397 +4,063 +12 Flow between WRIAs -19,389 -29,361 -9,972 -29 To WRIA 10 -56,546 -55,027 +1,519 +4 To WRIA 11 +37,157 +25,666 -11,491 -33 Model Simulations for Six Scenarios The groundwater-flow model was used to simulate possible effects on water levels and groundwater discharge caused by potential changes in well withdrawals and recharge. Six scenarios were formulated and simulated using the calibrated model to demonstrate how the model could be used to investigate water-resource issues under steady-state or transient conditions. Model results were compared to “base simulation” results that represent calibrated steady-state or transient conditions prior to modification for simulations. Resultant change in flow components (such as stream and lake, or spring and seep flows) are evaluated as a percent of the simulated change in recharge (table and as a percent of the simulated change in consumptive use (tables 10–12). Simulated increases in withdrawals were not applied to crop irrigation wells or to springs that supply public water. Model simulations were made to evaluate the following conditions: Simulation 1. Decrease recharge from precipitation by 20 percent throughout the model area to simulate drier conditions while maintaining all other “base simulation” steady-state conditions. Compare simulation results to “base simulation” (table 9 and fig. 15). ---PAGE BREAK--- Numerical Simulation of the Groundwater-Flow System 43 R. 05 E. T. 15 N. T. 15 N. T. 17 N. T. 18 N. T. 19 N. T. 20 N. T. 21 N. R. 04 E. R. 03 E. R. 02 E. R. 01 E. Puget Sound Lake Tapps American Lake Gravelly Lake Spanaway Lake Steilacoom Lake Ohop Lake Tanwax Lake Lake Kapowsin Swan Creek Puya llu p River C l o ver C re e k C h a m bers C r ee k Nis q ual l y R iv er N i s q u a l l y Riv e r P u y a ll u p R i v e r C a r b o n R i v e r M a s h e l Ri ver Ni sq ua ll y R iv e r M u c k C r e e k M u c k C re e k L acam a s C r e ek C l e a r C r e ek C la r k s Cr e ek Oho p C r e e k P u allup R iv er C lo v e r C r e ek S ou t h C re ek T a nwa x C re ek N. Fork C . C. S e q ua l i tc he w C r . Base from U.S. Geological Survey digital data, 1983, 1:100,000 Universal Transverse Mercator projection, Zone 10 Horizontal Datum: North American Datum of 1983 (NAD 83) 47°00° 46°50' 47°20' 30' 20' 122°10' 122°40' 10' 0 4 6 8 MILES 2 0 4 6 8 KILOMETERS 2 EXPLANATION Boundary of Water Resource Inventory Area Boundary of active model Groundwater level differences in aquifer A3 between base and Simulation 1, in feet -2.6 to -5.0 -51 to -7.5 -7.6 to -10.0 -12.6 to -15.0 -15.1 to -20.0 -20.1 to -30.0 -30.1 to -40.0 -10.1 to -12.5 -40.1 to -73.0 0 to -2.5 Figure 15. Simulated groundwater-level altitude change between the steady-state “base-simulation” and simulation 1, Chambers-Clover Creek watershed and vicinity, Washington. ---PAGE BREAK--- 44 Numerical Simulation of the Groundwater-Flow System in the Chambers-Clover Creek Watershed Simulation 2. Increase current withdrawals in all public supply and residential wells by 15 percent (with corresponding increases in return flows) under steady-state conditions. Compare simulation results to “base simulation” (table 10 and fig. 16). Table 10. Comparison of selected water budget components for the “base simulation” steady-state condition and simulations 2 and 3, Chambers-Clover Creek watershed and vicinity, Washington. [Flows equal inflow minus outflow; negative flows are out of the groundwater system or out of the WRIA. Column entries may not add exactly due to rounding. Abbreviations: acre-ft/yr, acre-feet per year; WRIA, water resources inventory area; NA, not applicable] Chambers-Clover Creek (WRIA12) Base simulation (acre-ft/yr) Simulation 2 (acre-ft/yr) Change from base simulation (acre-ft/yr) Percent of change in consumptive use Simulation 3 (acre-ft/yr) Change from base simulation (acre-ft/yr) Percent of change in consumptive use Recharge from precipitation 171,976 171,976 0 NA 171,976 0 NA Return flows 6,100 6,648 548 NA 6,648 548 NA Withdrawals from wells -32,909 -36,964 -4,055 NA -36,957 -4,047 NA Consumptive use -26,809 -30,315 -3,507 100 -30,308 -3,499 100 Streams and Lakes -17,281 -14,583 2,697 77 -14,805 2,476 71 Springs and seeps -27 -27 0 0 -27 0 0 Puget Sound -108,460 -107,961 499 14 -107,800 660 19 Flow between WRIAs -19,389 -19,084 304 9 -19,024 365 10 To WRIA 10 -56,546 -56,379 167 5 -56,340 206 6 To WRIA 11 37,157 37,295 138 4 37,316 158 4 Simulation 3. Increase current withdrawals in all public supply and residential wells by the same total amount in simulation 2 (with corresponding increases in return flows), but distribute that amount only in deeper wells under steady-state conditions. Deeper wells were simulated by assigning the additional Group A public-supply withdrawal amounts to the E aquifer and G undifferentiated deposits, and assigning the additional Group B public-supply and residential withdrawal amounts to the next lowest aquifer. Wells already located in the lowest hydrogeologic unit (G undifferentiated deposits) were not “deepened”. Compare simulation results to “base simulation” and Simulation 2 (table 10, fig. 17). ---PAGE BREAK--- Numerical Simulation of the Groundwater-Flow System 45 R. 05 E. T. 15 N. T. 15 N. T. 17 N. T. 18 N. T. 19 N. T. 20 N. T. 21 N. R. 04 E. R. 03 E. R. 02 E. R. 01 E. Puget Sound Lake Tapps American Lake Gravelly Lake Spanaway Lake Steilacoom Lake Ohop Lake Tanwax Lake Lake Kapowsin Swan Creek Puya llu p River C l o ver C re e k C h a m bers C r ee k Nis q ual l y R iv er N i s q u a l l y Riv e r P u y a ll u p R i v e r C a r b o n R i v e r M a s h e l Ri ver Ni sq ua ll y R iv e r M u c k C r e e k M u c k C re e k L acam a s C r e ek C l e a r C r e ek C la r k s Cr e ek Oho p C r e e k P u allup R iv er C lo v e r C r e ek S ou t h C re ek T a nwa x C re ek N. Fork C . C. S e q ua l i tc he w C r . Base from U.S. Geological Survey digital data, 1983, 1:100,000 Universal Transverse Mercator projection, Zone 10 Horizontal Datum: North American Datum of 1983 (NAD 83) 47°00° 46°50' 47°20' 30' 20' 122°10' 122°40' 10' 0 4 6 8 MILES 2 0 4 6 8 KILOMETERS 2 EXPLANATION Boundary of Water Resource Inventory Area Boundary of active model Groundwater level differences in aquifer A3 between base and Simulation 2, in feet 0.58 to 0.26 0.25 to 0.01 0 to -0.10 -0.11 to -0.20 -0.31 to -0.40 -0.41 to -0.60 -0.61 to -0.80 -0.81 to -1.00 -0.21 to -0.30 -1.01 to -3.30 Figure 16. Simulated groundwater-level altitude change between the steady-state “base-simulation” and simulation 2, Chambers-Clover Creek watershed and vicinity, Washington. ---PAGE BREAK--- 46 Numerical Simulation of the Groundwater-Flow System in the Chambers-Clover Creek Watershed R. 05 E. T. 15 N. T. 15 N. T. 17 N. T. 18 N. T. 19 N. T. 20 N. T. 21 N. R. 04 E. R. 03 E. R. 02 E. R. 01 E. Puget Sound Lake Tapps American Lake Gravelly Lake Spanaway Lake Steilacoom Lake Ohop Lake Tanwax Lake Lake Kapowsin Swan Creek Puya llu p River C l o ver C re e k C h a m bers C r ee k Nis q ual l y R iv er N i s q u a l l y Riv e r P u y a ll u p R i v e r C a r b o n R i v e r M a s h e l Ri ver Ni sq ua ll y R iv e r M u c k C r e e k M u c k C re e k L acam a s C r e ek C l e a r C r e ek C la r k s Cr e ek Oho p C r e e k P u allup R iv er N o . F or k C . C. C lo v e r C r e ek S ou t h C re ek T a nwa x C re ek N. Fork C . C. S e q ua l i tc he w C r . Base from U.S. Geological Survey digital data, 1983, 1:100,000 Universal Transverse Mercator projection, Zone 10 Horizontal Datum: North American Datum of 1983 (NAD 83) 47°00° 46°50' 47°20' 30' 20' 122°10' 122°40' 10' 0 4 6 8 MILES 2 0 4 6 8 KILOMETERS 2 EXPLANATION Boundary of Water Resource Inventory Area Boundary of active model Groundwater level differences in aquifer A3 between base and Simulation 3, in feet 0.57 to 0.26 0.25 to 0.01 0 to -0.10 -0.11 to -0.20 -0.31 to -0.40 -0.41 to -0.60 -0.61 to -0.80 -0.81 to -1.00 -0.21 to -0.30 -1.01 to -1.70 Figure 17. Simulated groundwater-level altitude change between the steady-state “base-simulation” and simulation 3, Chambers-Clover Creek watershed and vicinity, Washington. ---PAGE BREAK--- Numerical Simulation of the Groundwater-Flow System 47 Simulation 4. Increase current withdrawals in all public supply and residential wells by the same total amount in simulation 3 (with corresponding increases in return flows) and distribute that amount in Group A public-supply wells that have been deepened, and group B public-supply and residential wells that have not been deepened, under steady-state conditions. Compare simulation results to “base simulation” and Simulation 3 (table 11 and fig. 18). Table 11. Comparison of selected water budget components for the “base simulation” steady-state condition and simulations 3 and 4, Chambers-Clover Creek watershed and vicinity, Washington. [Flows equal inflow minus outflow; negative flows are out of the groundwater system or out of the WRIA. Column entries may not add exactly due to rounding. Abbreviation: acre-ft/yr, acre-feet per year; WRIA, water resources inventory area; NA, not applicable] Chambers-Clover Creek (WRIA12) Base simulation (acre-ft/yr) Simulation 3 (acre-ft/yr) Change from base simulation (acre-ft/yr) Percent of change in consumptive use Simulation 4 (acre-ft/yr) Change from base simulation (acre-ft/yr) Percent of change in consumptive use Recharge from precipitation 171,976 171,976 0 NA 171,976 0 NA Return flows 6,100 6,648 548 NA 6,648 548 NA Withdrawals from wells -32,909 -36,957 -4,047 NA -36,957 -4,047 NA Consumptive use -26,809 -30,308 -3,499 100 -30,308 -3,499 100 Streams and Lakes -17,281 -14,805 2,476 71 -14,805 2,476 71 Springs and seeps -27 -27 0 0 -27 0 0 Puget Sound -108,460 -107,800 660 19 -107,800 660 19 Flow between WRIAs -19,389 -19,024 365 10 -19,025 364 10 To WRIA 10 -56,546 -56,340 206 6 -56,340 206 6 To WRIA 11 37,157 37,316 158 4 37,315 158 4 ---PAGE BREAK--- 48 Numerical Simulation of the Groundwater-Flow System in the Chambers-Clover Creek Watershed Figure 18. Simulated groundwater-level altitude change between the steady-state “base-simulation” and simulation 4, Chambers-Clover Creek watershed and vicinity, Washington. R. 05 E. T. 15 N. T. 15 N. T. 17 N. T. 18 N. T. 19 N. T. 20 N. T. 21 N. R. 04 E. R. 03 E. R. 02 E. R. 01 E. Puget Sound Lake Tapps American Lake Gravelly Lake Spanaway Lake Steilacoom Lake Ohop Lake Tanwax Lake Lake Kapowsin Swan Creek Puya llu p River C l o ver C re e k C h a m bers C r ee k Nis q ual l y R iv er N i s q u a l l y Riv e r P u y a ll u p R i v e r C a r b o n R i v e r M a s h e l Ri ver Ni sq ua ll y R iv e r M u c k C r e e k M u c k C re e k L acam a s C r e ek C l e a r C r e ek C la r k s Cr e ek Oho p C r e e k P u allup R iv er C lo v e r C r e ek S ou t h C re ek T a nwa x C re ek N. Fork C . C. S e q ua l i tc he w C r . Base from U.S. Geological Survey digital data, 1983, 1:100,000 Universal Transverse Mercator projection, Zone 10 Horizontal Datum: North American Datum of 1983 (NAD 83) 47°00° 46°50' 47°20' 30' 20' 122°10' 122°40' 10' 0 4 6 8 MILES 2 0 4 6 8 KILOMETERS 2 EXPLANATION Boundary of Water Resource Inventory Area Boundary of active model Groundwater level differences in aquifer A3 between base and Simulation 4, in feet 0.57 to 0.26 0.25 to 0.01 0 to -0.10 -0.11 to -0.20 -0.31 to -0.40 -0.41 to -0.60 -0.61 to -0.80 -0.81 to -1.00 -0.21 to -0.30 -1.01 to -1.80 ---PAGE BREAK--- Numerical Simulation of the Groundwater-Flow System 49 Simulation 5. Increase current withdrawals under transient conditions in all public supply and residential wells by 15 percent (with corresponding increases in return flows) for the transient simulation period (September 2006–August 2008). Compare simulation results to “base simulation” (table 12 and fig. 19). Simulation 6. Increase current withdrawals under transient conditions in all public supply and residential wells by the same total amount in simulation 5 (with corresponding increases in return flows) for the transient simulation period (September 2006–August 2008). Distribute the increase in withdrawals during summer months (April–September) in deeper Group A public-supply wells, and Group B public supply and residential wells that have not been deepened. Distribute the increase in withdrawals during winter months (October–March) in Group A and Group B public supply wells and residential wells that have not been deepened. Compare simulation results to “base simulation” and to simulation 5 (table 12 and fig. 20). Table 12. Comparison of selected water budget components for the “base simulation” transient condition and simulations 5 and 6, Chambers-Clover Creek watershed and vicinity, Washington. [Flows equal inflow minus outflow averaged over 24 time steps during the transient simulation period, September 2006 – August 2008; negative flows are out of the groundwater system or out of the WRIA. Column entries may not add exactly due to rounding. Abbreviations: acre-ft/yr, acre-feet per year; WRIA, water resources inventory area; NA, not applicable] Chambers-Clover Creek (WRIA12) Base simulation (acre-ft/yr) Simulation 5 (acre-ft/yr) Change from base simulation (acre-ft/yr) Percent of change in consumptive use Simulation 6 (acre-ft/yr) Change from base simulation (acre-ft/yr) Percent of change in consumptive use Recharge from precipitation 171,980 171,980 0 NA 171,980 0 NA Return flows 6,103 6,652 549 NA 6,652 549 NA Withdrawals from wells -32,908 -36,956 -4,047 NA -36,956 -4,047 NA Consumptive use -26,806 -30,304 -3,498 100 -30,304 -3,498 100 From groundwater storage -2,513 -1,185 1,328 38 -1,222 1,290 37 Streams and Lakes -14,724 -13,300 1,424 41 -13,411 1,312 38 Springs and seeps -27 -27 0 0 -27 0 0 Puget Sound -108,105 -107,685 421 12 -107,586 519 15 Flow between WRIAs -19,823 -19,499 324 9 -19,447 376 11 To WRIA 10 -56,619 -56,531 88 3 -56,498 121 4 To WRIA 11 36,796 37,032 236 7 37,052 255 7 ---PAGE BREAK--- 50 Numerical Simulation of the Groundwater-Flow System in the Chambers-Clover Creek Watershed Figure 19. Simulated groundwater levels for transient “base-simulation” and simulation 5 and difference, Chambers-Clover Creek watershed and vicinity, Washington. Difference in groundwater level, in feet -1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0 Difference in groundwater level, in feet -1.2 -1.4 -1.6 -1.0 -0.8 -0.6 -0.4 -0.2 0 294 296 298 300 302 304 306 308 126 127 128 129 130 131 132 133 134 135 428 430 432 434 436 438 440 442 444 Difference in groundwater level, in feet -1.4 -1.0 -1.2 -0.8 -0.2 -0.6 -0.4 0 Difference in groundwater level, in feet -2.0 -1.8 -1.6 -1.4 -1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0 130 J 2006 2007 2008 M A M F J D N O S J M A M F J D N O S A J A J J 2006 2007 2008 M A M F J D N O S J M A M F J D N O S A J A J J 2006 2007 2008 M A M F J D N O S J M A M F J D N O S A J A J J 2006 2007 2008 M A M F J D N O S J M A M F J D N O S A J A J 132 134 136 138 140 142 144 Groundwater level, in feet above NAVD 88 Groundwater level, in feet above NAVD 88 Groundwater level, in feet above NAVD 88 Groundwater level, in feet above NAVD 88 Base EXPLANATION Simulation 5 Difference 19N/02E-04B03 Map index no. 75 Unit E Map index no. 72 Unit C 20N/02E-33C01 Map index no. 223 Unit C Map index no. 102 Unit C 19N/04E-20Q02 18N/04E-04P05 ---PAGE BREAK--- Numerical Simulation of the Groundwater-Flow System 51 Figure 20. Simulated groundwater levels for transient “base-simulation” and simulation 6 and difference, Chambers-Clover Creek watershed and vicinity, Washington. Difference in groundwater level, in feet -1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0 Difference in groundwater level, in feet -1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0 296 298 300 302 304 306 308 Groundwater level, in feet above NAVD 88 126 127 128 129 130 131 132 133 134 135 Groundwater level, in feet above NAVD 88 428 430 432 434 436 438 440 442 444 Difference in groundwater level, in feet -0.9 -0.8 -0.7 -0.5 -0.3 -0.2 -0.6 -0.4 -0.1 0 Difference in groundwater level, in feet -3.0 -2.5 -2.0 -1.5 -1.0 -0.5 0 128 J 2006 2007 2008 M A M F J D N O S J M A M F J D N O S A J A J J 2006 2007 2008 M A M F J D N O S J M A M F J D N O S A J A J J 2006 2007 2008 M A M F J D N O S J M A M F J D N O S A J A J J 2006 2007 2008 M A M F J D N O S J M A M F J D N O S A J A J Groundwater level, in feet above NAVD 88 130 132 134 136 138 140 142 144 Groundwater level, in feet above NAVD 88 Base EXPLANATION Simulation 6 Difference 19N/02E-04B03 Map index no. 75 Unit E Map index no. 72 Unit C 20N/02E-33C01 Map index no. 102 Unit C 19N/04E-20Q02 18N/04E-04P05 Map index no. 223 Unit C ---PAGE BREAK--- 52 Numerical Simulation of the Groundwater-Flow System in the Chambers-Clover Creek Watershed Model simulations are briefly summarized below: Model Simulation Recharge (precipitation and return flows) Withdrawal amount (public and residential) Withdrawal location Simulation 1 Steady-State Decrease precipitation recharge by 20 percent No change No change Simulation 2 Steady-State Increase return flows by 15 percent Increase public and residential withdrawals by 15 percent No change Simulation 3 Steady-State Increase return flows by 15 percent Increase public and residential withdrawals by 15 percent Deepen all public and residential withdrawals Simulation 4 Steady-State Increase return flows by 15 percent Increase public and residential withdrawals by 15 percent Deepen only group A public withdrawals Simulation 5 Transient Increase return flows by 15 percent Increase public and residential withdrawals by 15 percent No change Simulation 6 Transient Increase return flows by 15 percent Increase public and residential withdrawals by 15 percent Deepen only group A public withdrawals during summer months Simulation 1 reduces the amount of groundwater recharge from precipitation to simulate drier climatic conditions. The resulting change in flow components for simulation 1 (table 9) indicate that a 34,395 acre-ft/yr reduction in groundwater recharge from precipitation produces a reversal in the net exchange of groundwater and surface-water in WRIA12 from a loss of 17,281 acre-ft/yr of groundwater to streams and lakes, to a gain of 23,009 acre-ft/yr of groundwater from streams and lakes, and a reduction or loss of spring flows from 27 acre-ft/yr to 22 acre-ft/yr. Groundwater discharge to Puget Sound is reduced by 4,063 acre-ft/yr, and groundwater flow from WRIA12 to WRIA10 and WRIA11 is increased by 9,972 acre-ft/yr. Simulated water level declines in the A3 aquifer typically ranged from about 30 ft to less than 1 ft, with a maximum decline of 64 ft (fig. 15). The change in flow components for simulation 2 (table 10) indicate that of the 3,507 acre-ft/yr of increased consumptive withdrawals (pumpage in wells minus return flows), a majority (2,697 acre-ft/yr or 77 percent) comes from decreased groundwater discharge to streams and lakes; that 499 acre-ft/yr (14 percent) comes from decreased groundwater discharge to Puget Sound; and that 304 acre-ft/ yr (9 percent) comes from decreased flow from WRIA12 to WRIA10 and WRIA11. Simulated water level declines in the A3 aquifer resulting from increased withdrawals typically ranged from about 0.6 ft to less than 0.1 ft with a maximum decline of about 3.3 ft (fig. 16). Water-level declines are greatest in areas of higher well density. The change in flow components for simulation 3 (table 10) indicate a slight reduction in the amount of consumptive withdrawal derived from streams and lakes (2,476 acre-ft/yr, or 71 percent) resulting from the distribution of withdrawals among deeper wells. Slight increases in the amount of consumptive withdrawal derived from groundwater discharge to Puget Sound (660 acre-ft/yr or 19 percent) and flow from WRIA12 to WRIA10 and WRIA11 (365 acre-ft/ yr or 10 percent) result from the distribution of withdrawals among deeper wells. The relatively minor influence of withdrawals from deeper wells on the amount of consumptive withdrawal derived from streams and lakes may be due to increased groundwater discharge to streams through enhanced shallow groundwater recharge from increased return flows from deeper withdrawals. Simulated water level declines in the A3 aquifer resulting from increased withdrawals from deeper wells typically ranged from about 0.6 ft to less than 0.1 ft with a maximum decline of about 1.7 ft (fig. 17). Water- level declines are greatest in areas of higher well density. A comparison of the simulated change in groundwater level between simulations 2 and 3 (figs. 16 and 17, respectively) suggests that withdrawals from deeper wells reduced simulated groundwater level lowering in the A3 aquifer in areas of higher well density. ---PAGE BREAK--- Summary 53 Simulation 4 applies the same increase in withdrawal as simulation 3, but distributes that amount in Group A public- supply wells that have been deepened, and Group B public- supply and residential wells that have not been deepened. Results from this simulation are compared with results from simulation 3 to evaluate the relative impact of potential future increases in withdrawals from deeper Group A public-supply wells compared with the present-day depth distribution of Group B public supply and residential withdrawals. The change in flow components for simulation 4 (table 11) indicate that the effect of the present-day depth distribution of Group B public-supply and residential well withdrawals was not of sufficient magnitude to produce a response in water budget components in WRIA12. A comparison of the simulated change in groundwater level between simulations 3 and 4 (figs. 17 and 18, respectively) suggests that the effect of the present-day depth distribution of Group B public-supply and residential well withdrawals was not of sufficient magnitude to produce a response in simulated groundwater levels in the A3 aquifer. This lack of response may be the result of the relatively small amount of additional consumptive use associated with Group B public-supply and residential withdrawals compared with the amount of recharge from precipitation. Simulations 5 and 6 were made using the model for transient conditions. Simulation 5 increases withdrawals in all public-supply and residential wells. The resulting change in flow components for simulation 5 (table 12) indicate that, of the 3,498 acre-ft/yr of increased consumptive withdrawals over the 2-year transient simulation period, the majority (79 percent) comes from decreased groundwater discharge to streams and lakes (1,424 acre-ft/ yr, or 41 percent) and from decreased groundwater storage (1,328 acre-ft/r or 38 percent), 421 acre-ft/yr (12 percent) comes from decreased groundwater discharge to Puget Sound and 324 acre-ft/yr (9 percent) comes from flow from WRIA12 to WRIA10 and WRIA11. Representative hydrographs of groundwater levels for the transient simulation period illustrate differences of less than 2 ft between the “base simulation” and Simulation 5 (fig. 19). Continually increasing water‑level differences suggest that the effects of withdrawals at mid and deep levels of the aquifer system did not stabilize during the simulation period, and that a continued loss of groundwater storage is likely. Simulation 6 increases withdrawals in all public- supply and residential wells by the same total amount in simulation 5, but distributes the increase in withdrawals during summer months (April–September) to Group A public-supply wells that have been deepened, and Group B public supply and residential wells that have not been deepened. Results from this simulation are compared to results from simulation 5 to evaluate the potential mitigation of adverse impacts on water levels and stream baseflows by deepening Group A public- supply withdrawals during summer months. The resulting change in flow components for simulation 6 (table 12) indicate a decrease in the amount of consumptive withdrawal derived from streams and lakes (1,312 acre-ft/yr, or 38 percent) and from groundwater storage (1,290 acre-ft/yr, or 37 percent), and an increase in both the amount of consumptive withdrawal derived from groundwater discharge to Puget Sound (519 acre-ft/yr, or 15 percent), and flow from WRIA12 to WRIA10 and WRIA11 (376 acre-ft/yr, or 11 percent). A comparison of groundwater-difference hydrographs between simulations 5 and 6 (figs. 19 and 20) indicate that deepening Group A public-supply during the summer delayed by several months the timing of the greatest simulated impact of withdrawals in a well (map index no. 102) completed in the C aquifer and located within an area containing several nearby Group A public-supply wells. A similar delay in groundwater-level response was not observed for other wells (map index no. 72 and 223) completed in the C aquifer that are located within areas containing fewer nearby Group A public wells. The deepening of Group A public-supply withdrawals during the summer decreased simulated groundwater-level declines during the summer months in two wells (map index no. 72 and 102) completed in the C aquifer, and increased simulated groundwater-level declines in a well (map index no. 75) completed in the E aquifer. Summary In 1998, the Washington State Legislature established the Washington State Watershed Management Act (codified under RCW 90.82) to address the diminishing availability and quality of water and the loss of critical habitat for fish and wildlife. Watershed studies under this Act were begun in 1998 in the Chambers–Clover Creek Watershed (CCCW) Water Resources Inventory Area (WRIA 12) by a group of Initiating Governments and local stakeholders (the Planning Unit). Upon completion of a technical assessment of the watershed, some members of the Planning Unit concluded that additional data, including development of a numerical groundwater- flow model, would contribute to an improved understanding of water resources in the CCCW. A groundwater-flow model was constructed by the U.S. Geological Survey to assist stake holders in developing an improved understanding of water resources in the CCCW and vicinity. The model covers an area of about 491 mi2 in western Pierce County, Washington (fig. and was selected to include major hydrologic features that could be used as regional model boundaries during development of the numerical flow model of the CCCW and vicinity. The model area is bounded to the northeast by the Puyallup River valley, to the southwest by the Nisqually River valley, and extends northwest to Puget Sound, and southeast to Tanwax Creek which approximates the southeastern extent of the majority of water-bearing hydrogeologic units. The model ---PAGE BREAK--- 54 Numerical Simulation of the Groundwater-Flow System in the Chambers-Clover Creek Watershed area is underlain by a northwest-thickening sequence of unconsolidated glacial (till and outwash) and interglacial (fluvial and lacustrine) deposits. Sedimentary and volcanic bedrock units underlie the unconsolidated deposits, and crop out in a few areas within deeply incised river valleys along the southern and southeastern margin of the model area. Groundwater flow in the CCCW and vicinity was simulated using the groundwater-flow model, MODFLOW-2000. The finite‑difference model grid comprises 146 rows, 132 columns, and 11 layers. Each model cell has a horizontal dimension of 1,000 by 1,000 ft, and the model contains a total of 123,602 active cells. The thickness of model layers varies throughout the model area. Boundary conditions representing inflow and outflow components were implemented using packages in MODFLOW-2000. The Recharge Package was used to represent recharge from precipitation and water returned to the groundwater system through seepage from septic systems, deep percolation of irrigation water, and public water-system conveyance losses. The Well Package was used to represent withdrawals from wells. The River Package was used to represent the exchange of water between streams, lakes, and the aquifer system. The Drain Package was used to represent groundwater discharge to springs and seeps, and the General-Head Boundary Package was used to represent groundwater discharge to Puget Sound. Groundwater flow was simulated in unconsolidated glacial (till and outwash) and interglacial (fluvial and lacustrine) deposits in the CCCW and vicinity. The hydrogeologic framework presented in Savoca and others (2010) was used to delineate 10 hydrogeologic units comprising aquifers and confining units within the model domain that are represented using 11 model layers. Initial estimates and probable ranges of values for hydraulic properties used during model calibration were defined from data collected during previous studies in and adjacent to the model area. Groundwater flow was simulated for both steady- state and transient conditions. Steady-state conditions were simulated using average recharge, discharge, and water levels for the period, September 2006–August 2008. Transient conditions were simulated for the period, September 2006– August 2008 using 24 stress periods. Initial conditions for the transient calibrations were developed from a 3-year “lead-in” period that used recorded precipitation and river levels, and extrapolations of other boundary conditions. During model calibration, variables were adjusted within probable ranges to minimize differences between measured and simulated groundwater levels and stream baseflows. The model as calibrated to steady-state conditions has a standard deviation for heads and flows of 28.42 ft and 2.12 cubic feet per second, respectively; the model as calibrated to transient conditions has a standard deviation for heads and flows of 23.01 ft and 2.67 cubic feet per second, respectively. Simulated steady-state inflow to the model area from precipitation and secondary recharge was 477,266 acre- feet per year (acre-ft/yr) (79 percent of total simulated inflow), and simulated inflow from stream and lake leakage was129,778 acre-ft/yr (21 percent of total simulated inflow). Simulated outflow from the model primarily was through discharge to streams, lakes, springs, seeps, and Puget Sound (559,192 acre-ft/yr; 92 percent of total simulated outflow), and withdrawals from wells (47,863 acre-ft/yr; 8 percent of total simulated outflow). Six scenarios were formulated and simulated using the calibrated model to demonstrate model performance and to provide representative examples of how the model can be used to evaluate the effects of potential changes in groundwater withdrawals, consumptive use, and recharge on groundwater levels and stream baseflows. Acknowledgments The authors wish to thank the many well owners in the model area who provided access to their wells. The authors also acknowledge the assistance and information provided by public water-supply systems and water districts; these include Spanaway Water Company, Fruitland Mutual Water Company, Parkland Light and Water Company, Summit Water and Supply Company, Lakewood Water District, and the cities of Tacoma, Milton, and Fife. The authors also thank Tacoma– Pierce County Health Department, Pierce County Water Utility, and Fort Lewis for providing well data. Information used to characterize the groundwater-flow system was generously provided by Robinson-Noble Inc., and the Pacific Groundwater Group. Selected References Bidlake, W.R., and Payne, K.L., 2001, Estimating recharge to ground water from precipitation at Naval Submarine Base Bangor and Vicinity, Kitsap County, Washington: U.S Geological Survey Water Resources Investigations Report 01-4110, 33 p. Blair, H.O., 1929, Underground water resources in the vicinity of Tacoma: Journal of the American Water Works Association, v. 21, no. 9, p. 1185–1195. Carr/Associates Inc., 1988, Report on the 1987–88 test drilling program for the City of Tacoma Czuba, J.A., Czuba, C.R., Magirl, C.S., and Voss, F.D., 2010, Channel-conveyance capacity, channel change, and sediment transport in the lower Puyallup, White, and Carbon Rivers, western Washington: U.S. Geological Survey Scientific Investigations Report 2010–5240, 104 p. ---PAGE BREAK--- Selected References 55 Doherty, John, 2003, Ground water model calibration using pilot points and regularization: Ground Water, v. 41, no. 2, p. 170–177. Doherty, 2005, PEST: Model-independent parameter estimation: Watermark Numerical Computing, Corinda, Australia, [variously paged]. Doherty, 2006, Addendum to PEST manual: Watermark Numerical Computing, Corinda, Australia, [variously paged]. Doherty, Fienen, M.N., and Hunt, R.J., 2010, Approaches to highly parameterized inversion: pilot-point theory guidelines, and Research Directions: U.S. Geological Survey Scientific Investigations Report 2010-5168, 36 p. Doherty, J.E., and Hunt, R.J., 2010, Approaches to highly parameterized inversion—A guide to using PEST for groundwater-model calibration: U.S. Geological Survey Scientific Investigations Report 2010–5169, 59 p. Drost, B.W., Ely, D.M., and Lum II, W.E., 1999, Conceptual model and numerical simulation of the ground-water-flow system in the unconsolidated sediments of Thurston County, Washington: U.S. Geological Survey Water-Resources Investigations Report 99-4165, 254 p. Fienen, M.N., Muffels, C.J., and Hunt, R.J., 2009, Methods note—On constraining pilot point calibration with regularization in PEST: Ground Water, v. 47, no. 6, p. 835–844. Freeze, R.A., and Cherry, J.A., 1979, Groundwater: Englewood Cliffs, NJ, Prentice-Hall, 604 p. GeoEngineers, 2003, Lower and upper Skagit watershed plan Samish River sub-basin, ground water hydrology evaluation: file no. 7291-[SSN REDACTED], 175 p. Harbaugh, A.W., Banta, E.R., Hill, M.C., and McDonald, M.G., 2000, MODFLOW-2000, the U.S. Geological Survey modular ground-water model—User guide to modularization concepts and the ground-water flow process: U.S. Geological Survey Open-File Report 00-92, 121 accessed May, 2009, at http://water.usgs.gov/nrp/ gwsoftware/modflow2000/ofr00-92.pdf. Hill, M.C., and Tiedeman, C.R., 2007, Effective groundwater model calibration—With analysis of data, sensitivities, predictions and uncertainty: Hoboken, N.J., Wiley, 464 p. Hsieh, P.A., Barber, M.E., Contor, B.A., Hossain, Md. Johnson, G.S., Jones, J.L., and Wylie, A.H., 2007, Ground- water flow model for the Spokane Valley–Rathdrum Prairie Aquifer, Spokane County, Washington, and Bonner and Kootenai Counties, Idaho: U.S. Geological Survey Scientific Investigations Report 2007–5044, 78 p. (Also available at http://pubs.usgs.gov/sir/2007/5044/.) Jones, M.A., 1999, Geologic framework for the Puget Sound aquifer system, Washington and British Columbia: U.S. Geological Survey Professional Paper 1424-C, 31 18 plates, scale 1:500,000 and scale 1:100,000. Jones, M.A., Orr, L.A., Ebbert, J.C., and Sumioka, S.S., 1999, Ground-water hydrology of the Tacoma-Puyallup area, Pierce County, Washington: U.S. Geological Survey Water- Resources Investigations Report 99–4013, 154 p. Justin, G.B., Julich, and Payne, K.L., 2009, Hydrographs showing groundwater level changes for selected wells in the Chambers-Clover Creek watershed and vicinity, Pierce County, Washington: U.S. Geological Survey Data Series 453. Oad, Ramchand, Lusk, Kevin, and Podmore, Terry, 1997, Consumptive use and return flows on urban lawn water use: Journal of Irrigation and Drainage Engineering, v. 123, issue 1, p. 62–69. Oad, Ramchand, and DiSpigno, Michale, 1997, Water rights to return flow from urban landscape irrigation: Journal of Irrigation and Drainage Engineering, v. 123, issue 4, p. 293–299. Savoca, M.E., Welch, W.B., Johnson, K.H., Lane, R. Clothier, B.C., and Fasser, E.T., 2010, Hydrogeologic Framework, Groundwater Movement, and Water Budget in the Chambers–Clover Creek Watershed and Vicinity, Pierce County, Washington: U.S. Geological Survey Scientific Investigations Report 2010–5055, 46 p. Sapik, D.B., Bortleson, G.C., Drost, B.W., Jones, M.A., and E.A., 1989, Ground-water resources and simulation of flow in aquifers containing freshwater and seawater, Island County, Washington: U.S. Geological Survey Water- Resources Investigations Report 87–4182, 67 p. Sceva, J.E., Wegner, D.E., and others, 1955, Records of wells and springs, water levels, and quality of ground water in central Pierce County, Washington: U.S. Geological Survey Open-File Report 55-160, 261 p. Vaccaro, J.J., A.J. Hansen, and M.S. Jones. 1998, Hydrogeologic framework for the Puget Sound aquifer system, Washington and British Columbia: U.S. Geological Survey Professional Paper 1424-D, 77 p. van Heeswijk, Marijke, and Smith, D.T., 2002, Simulation of the ground-water flow system at Naval Submarine Base Bangor and vicinity, Kitsap County, Washington: U.S. Geological Survey Water-Resources Investigations Report 02–4261, 142 p. (Also available at http://pubs.usgs.gov/wri/ wri024261/). Walters, K.L., and Kimmel, G.E., 1968, Ground-water occurrence and stratigraphy of unconsolidated deposits, central Pierce County, Washington: Washington State Department of Water Resources Water-Supply Bulletin no. 22, 428 p. ---PAGE BREAK--- 56 Numerical Simulation of the Groundwater-Flow System in the Chambers-Clover Creek Watershed Figure 21. Extent and thickness of hydrogeologic units simulated with the Layer-Property Flow package, Chambers-Clover Creek watershed and vicinity, Washington. R. 05 E. T. 15 N. T. 15 N. T. 17 N. T. 18 N. T. 19 N. T. 20 N. T. 21 N. R. 04 E. R. 03 E. R. 02 E. R. 01 E. Puget Sound Lake Tapps American Lake Gravelly Lake Spanaway Lake Steilacoom Lake Ohop Lake Tanwax Lake Lake Kapowsin Swan Creek Puya llu p River C l o ver C re e k C h a m bers C r ee k Nis q ual l y R iv er N i s q u a l l y Riv e r P u y a ll u p R i v e r C a r b o n R i v e r M a s h e l Ri ver Ni sq ua ll y R iv e r M u c k C r e e k M u c k C re e k L acam a s C r e ek C l e a r C r e ek C la r k s Cr e ek Oho p C r e e k P u allup R iv er C lo v e r C r e ek S ou t h C re ek T a nwa x C re ek N. Fork C . C. S e q ua l i tc he w C r . Base from U.S. Geological Survey digital data, 1983, 1:100,000 Universal Transverse Mercator projection, Zone 10 Horizontal Datum: North American Datum of 1983 (NAD 83) 47°00° 46°50' 47°20' 30' 20' 122°10' 122°40' 10' 0 4 6 8 MILES 2 0 4 6 8 KILOMETERS 2 Extent and thickness of Hydrogeologic Unit AL, in feet 1 to 50 51 to 100 101 to 200 201 to 300 301 to 322 EXPLANATION Boundary of Water Resource Inventory Area Boundary of active model Unit not present A ---PAGE BREAK--- Figure 21 57 Figure 21.—Continued R. 05 E. T. 15 N. T. 15 N. T. 17 N. T. 18 N. T. 19 N. T. 20 N. T. 21 N. R. 04 E. R. 03 E. R. 02 E. R. 01 E. Puget Sound Lake Tapps American Lake Gravelly Lake Spanaway Lake Steilacoom Lake Ohop Lake Tanwax Lake Lake Kapowsin Swan Creek Puya llu p River C l o ver C re e k C h a m bers C r ee k Nis q ual l y R iv er N i s q u a l l y Riv e r P u y a ll u p R i v e r C a r b o n R i v e r M a s h e l Ri ver Ni sq ua ll y R iv e r M u c k C r e e k M u c k C re e k L acam a s C r e ek C l e a r C r e ek C la r k s Cr e ek Oho p C r e e k P u allup R iv er C lo v e r C r e ek S ou t h C re ek T a nwa x C re ek N. Fork C . C. S e q ua l i tc he w C r . Base from U.S. Geological Survey digital data, 1983, 1:100,000 Universal Transverse Mercator projection, Zone 10 Horizontal Datum: North American Datum of 1983 (NAD 83) 47°00° 46°50' 47°20' 30' 20' 122°10' 122°40' 10' 0 4 6 8 MILES 2 0 4 6 8 KILOMETERS 2 Extent and thickness of Hydrogeologic Unit A1, in feet 1 to 50 51 to 100 101 to 200 201 to 206 EXPLANATION Boundary of Water Resource Inventory Area Boundary of active model Unit not present B ---PAGE BREAK--- 58 Numerical Simulation of the Groundwater-Flow System in the Chambers-Clover Creek Watershed R. 05 E. T. 15 N. T. 15 N. T. 17 N. T. 18 N. T. 19 N. T. 20 N. T. 21 N. R. 04 E. R. 03 E. R. 02 E. R. 01 E. Puget Sound Lake Tapps American Lake Gravelly Lake Spanaway Lake Steilacoom Lake Ohop Lake Tanwax Lake Lake Kapowsin Swan Creek Puya llu p River C l o ver C re e k C h a m bers C r ee k Nis q ual l y R iv er N i s q u a l l y Riv e r P u y a ll u p R i v e r C a r b o n R i v e r M a s h e l Ri ver Ni sq ua ll y R iv e r M u c k C r e e k M u c k C re e k L acam a s C r e ek C l e a r C r e ek C la r k s Cr e ek Oho p C r e e k P u allup R iv er C lo v e r C r e ek S ou t h C re ek T a nwa x C re ek N. Fork C . C. S e q ua l i tc he w C r . Base from U.S. Geological Survey digital data, 1983, 1:100,000 Universal Transverse Mercator projection, Zone 10 Horizontal Datum: North American Datum of 1983 (NAD 83) 47°00° 46°50' 47°20' 30' 20' 122°10' 122°40' 10' 0 4 6 8 MILES 2 0 4 6 8 KILOMETERS 2 Extent and thickness of Hydrogeologic Unit A2, in feet 1 to 50 51 to 100 101 to 200 201 to 300 301 to 323 EXPLANATION Boundary of Water Resource Inventory Area Boundary of active model Unit not present C Figure 21.—Continued ---PAGE BREAK--- Figure 21 59 R. 05 E. T. 15 N. T. 15 N. T. 17 N. T. 18 N. T. 19 N. T. 20 N. T. 21 N. R. 04 E. R. 03 E. R. 02 E. R. 01 E. Puget Sound Lake Tapps American Lake Gravelly Lake Spanaway Lake Steilacoom Lake Ohop Lake Tanwax Lake Lake Kapowsin Swan Creek Puya llu p River C l o ver C re e k C h a m bers C r ee k Nis q ual l y R iv er N i s q u a l l y Riv e r P u y a ll u p R i v e r C a r b o n R i v e r M a s h e l Ri ver Ni sq ua ll y R iv e r M u c k C r e e k M u c k C re e k L acam a s C r e ek C l e a r C r e ek C la r k s Cr e ek Oho p C r e e k P u allup R iv er C lo v e r C r e ek S ou t h C re ek T a nwa x C re ek N. Fork C . C. S e q ua l i tc he w C r . Base from U.S. Geological Survey digital data, 1983, 1:100,000 Universal Transverse Mercator projection, Zone 10 Horizontal Datum: North American Datum of 1983 (NAD 83) 47°00° 46°50' 47°20' 30' 20' 122°10' 122°40' 10' 0 4 6 8 MILES 2 0 4 6 8 KILOMETERS 2 Extent and thickness of Hydrogeologic Unit A3, in feet 1 to 50 51 to 100 101 to 200 201 to 300 301 to 329 EXPLANATION Boundary of Water Resource Inventory Area Boundary of active model Unit not present D Figure 21.—Continued ---PAGE BREAK--- 60 Numerical Simulation of the Groundwater-Flow System in the Chambers-Clover Creek Watershed R. 05 E. T. 15 N. T. 15 N. T. 17 N. T. 18 N. T. 19 N. T. 20 N. T. 21 N. R. 04 E. R. 03 E. R. 02 E. R. 01 E. Puget Sound Lake Tapps American Lake Gravelly Lake Spanaway Lake Steilacoom Lake Ohop Lake Tanwax Lake Lake Kapowsin Swan Creek Puya llu p River C l o ver C re e k C h a m bers C r ee k Nis q ual l y R iv er N i s q u a l l y Riv e r P u y a ll u p R i v e r C a r b o n R i v e r M a s h e l Ri ver Ni sq ua ll y R iv e r M u c k C r e e k M u c k C re e k L acam a s C r e ek C l e a r C r e ek C la r k s Cr e ek Oho p C r e e k P u allup R iv er C lo v e r C r e ek S ou t h C re ek T a nwa x C re ek N. Fork C . C. S e q ua l i tc he w C r . Base from U.S. Geological Survey digital data, 1983, 1:100,000 Universal Transverse Mercator projection, Zone 10 Horizontal Datum: North American Datum of 1983 (NAD 83) 47°00° 46°50' 47°20' 30' 20' 122°10' 122°40' 10' 0 4 6 8 MILES 2 0 4 6 8 KILOMETERS 2 Extent and thickness of Hydrogeologic Unit B, in feet 1 to 50 51 to 100 101 to 200 201 to 300 301 to 340 EXPLANATION Boundary of Water Resource Inventory Area Boundary of active model Unit not present E Figure 21.—Continued ---PAGE BREAK--- Figure 21 61 Figure 21.—Continued R. 05 E. T. 15 N. T. 15 N. T. 17 N. T. 18 N. T. 19 N. T. 20 N. T. 21 N. R. 04 E. R. 03 E. R. 02 E. R. 01 E. Puget Sound Lake Tapps American Lake Gravelly Lake Spanaway Lake Steilacoom Lake Ohop Lake Tanwax Lake Lake Kapowsin Swan Creek Puya llu p River C l o ver C re e k C h a m bers C r ee k Nis q ual l y R iv er N i s q u a l l y Riv e r P u y a ll u p R i v e r C a r b o n R i v e r M a s h e l Ri ver Ni sq ua ll y R iv e r M u c k C r e e k M u c k C re e k L acam a s C r e ek C l e a r C r e ek C la r k s Cr e ek Oho p C r e e k P u allup R iv er C lo v e r C r e ek S ou t h C re ek T a nwa x C re ek N. Fork C . C. S e q ua l i tc he w C r . Base from U.S. Geological Survey digital data, 1983, 1:100,000 Universal Transverse Mercator projection, Zone 10 Horizontal Datum: North American Datum of 1983 (NAD 83) 47°00° 46°50' 47°20' 30' 20' 122°10' 122°40' 10' 0 4 6 8 MILES 2 0 4 6 8 KILOMETERS 2 Extent and thickness of Hydrogeologic Unit C, in feet 1 to 50 51 to 100 101 to 200 201 to 277 EXPLANATION Boundary of Water Resource Inventory Area Boundary of active model Unit not present F ---PAGE BREAK--- 62 Numerical Simulation of the Groundwater-Flow System in the Chambers-Clover Creek Watershed R. 05 E. T. 15 N. T. 15 N. T. 17 N. T. 18 N. T. 19 N. T. 20 N. T. 21 N. R. 04 E. R. 03 E. R. 02 E. R. 01 E. Puget Sound Lake Tapps American Lake Gravelly Lake Spanaway Lake Steilacoom Lake Ohop Lake Tanwax Lake Lake Kapowsin Swan Creek Puya llu p River C l o ver C re e k C h a m bers C r ee k Nis q ual l y R iv er N i s q u a l l y Riv e r P u y a ll u p R i v e r C a r b o n R i v e r M a s h e l Ri ver Ni sq ua ll y R iv e r M u c k C r e e k M u c k C re e k L acam a s C r e ek C l e a r C r e ek C la r k s Cr e ek Oho p C r e e k P u allup R iv er C lo v e r C r e ek S ou t h C re ek T a nwa x C re ek N. Fork C . C. S e q ua l i tc he w C r . Base from U.S. Geological Survey digital data, 1983, 1:100,000 Universal Transverse Mercator projection, Zone 10 Horizontal Datum: North American Datum of 1983 (NAD 83) 47°00° 46°50' 47°20' 30' 20' 122°10' 122°40' 10' 0 4 6 8 MILES 2 0 4 6 8 KILOMETERS 2 Extent and thickness of Hydrogeologic Unit D, in feet 1 to 50 EXPLANATION 51 to 100 101 to 200 201 to 300 Boundary of Water Resource Inventory Area 301 to 400 Unit not present Boundary of active model G Figure 21.—Continued ---PAGE BREAK--- Figure 21 63 R. 05 E. T. 15 N. T. 15 N. T. 17 N. T. 18 N. T. 19 N. T. 20 N. T. 21 N. R. 04 E. R. 03 E. R. 02 E. R. 01 E. Puget Sound Lake Tapps American Lake Gravelly Lake Spanaway Lake Steilacoom Lake Ohop Lake Tanwax Lake Lake Kapowsin Swan Creek Puya llu p River C l o ver C re e k C h a m bers C r ee k Nis q ual l y R iv er Ni squally Riv er P u y a ll u p R i v e r C a r b o n R i v e r M a s h e l Ri ver Ni sq ua ll y R iv e r M u c k C r e e k M u c k C re e k L acam a s C r e ek C l e a r C r e ek C la r k s Cr e ek Oho p C r e e k P u allup R iv er C lo v e r C r e ek S ou t h C re ek T a nwa x C re ek N. Fork C . C. S e q ua l i tc he w C r . Base from U.S. Geological Survey digital data, 1983, 1:100,000 Universal Transverse Mercator projection, Zone 10 Horizontal Datum: North American Datum of 1983 (NAD 83) 47°00° 46°50' 47°20' 30' 20' 122°10' 122°40' 10' 0 4 6 8 MILES 2 0 4 6 8 KILOMETERS 2 Extent and thickness of Hydrogeologic Unit E, in feet 1 to 50 51 to 100 101 to 200 201 to 300 301 to 400 301 to 400 401 to 471 EXPLANATION Boundary of Water Resource Inventory Area Boundary of active model Unit not present H Figure 21.—Continued ---PAGE BREAK--- 64 Numerical Simulation of the Groundwater-Flow System in the Chambers-Clover Creek Watershed R. 05 E. T. 15 N. T. 15 N. T. 17 N. T. 18 N. T. 19 N. T. 20 N. T. 21 N. R. 04 E. R. 03 E. R. 02 E. R. 01 E. Puget Sound Lake Tapps American Lake Gravelly Lake Spanaway Lake Steilacoom Lake Ohop Lake Tanwax Lake Lake Kapowsin Swan Creek Puya llu p River C l o ver C re e k C h a m bers C r ee k Nis q ual l y R iv er Ni squally Riv er P u y a ll u p R i v e r C a r b o n R i v e r M a s h e l Ri ver Ni sq ua ll y R iv e r M u c k C r e e k M u c k C re e k L acam a s C r e ek C l e a r C r e ek C la r k s Cr e ek Oho p C r e e k P u allup R iv er C lo v e r C r e ek S ou t h C re ek T a nwa x C re ek N. Fork C . C. S e q ua l i tc he w C r . Base from U.S. Geological Survey digital data, 1983, 1:100,000 Universal Transverse Mercator projection, Zone 10 Horizontal Datum: North American Datum of 1983 (NAD 83) 47°00° 46°50' 47°20' 30' 20' 122°10' 122°40' 10' 0 4 6 8 MILES 2 0 4 6 8 KILOMETERS 2 Extent and thickness of Hydrogeologic Unit F, in feet 1 to 50 51 to 100 101 to 200 201 to 300 301 to 400 301 to 400 401 to 500 501 to 576 EXPLANATION Boundary of Water Resource Inventory Area Boundary of active model Unit not present I Figure 21.—Continued ---PAGE BREAK--- Figure 21 65 R. 05 E. T. 15 N. T. 15 N. T. 17 N. T. 18 N. T. 19 N. T. 20 N. T. 21 N. R. 04 E. R. 03 E. R. 02 E. R. 01 E. Puget Sound Lake Tapps American Lake Gravelly Lake Spanaway Lake Steilacoom Lake Ohop Lake Tanwax Lake Lake Kapowsin Swan Creek Puya llu p River C l o ver C re e k C h a m bers C r ee k Nis q ual l y R iv er Ni squally Riv er P u y a ll u p R i v e r C a r b o n R i v e r M a s h e l Ri ver Ni sq ua ll y R iv e r M u c k C r e e k M u c k C re e k L acam a s C r e ek C l e a r C r e ek C la r k s Cr e ek Oho p C r e e k P u allup R iv er C lo v e r C r e ek S ou t h C re ek T a nwa x C re ek N. Fork C . C. S e q ua l i tc he w C r . Base from U.S. Geological Survey digital data, 1983, 1:100,000 Universal Transverse Mercator projection, Zone 10 Horizontal Datum: North American Datum of 1983 (NAD 83) 47°00° 46°50' 47°20' 30' 20' 122°10' 122°40' 10' 0 4 6 8 MILES 2 0 4 6 8 KILOMETERS 2 Extent and thickness of Hydrogeologic Unit G, in feet 1 to 200 201 to 400 401 to 600 601 to 800 801 to 1,000 1,001 to 1,200 1,201 to 1,400 1,401 to 1,567 EXPLANATION Boundary of Water Resource Inventory Area Boundary of active model Unit not present J Figure 21.—Continued ---PAGE BREAK--- 66 Numerical Simulation of the Groundwater-Flow System in the Chambers-Clover Creek Watershed Figure 22. Final parameter value distributions of horizontal (A–J) and vertical hydraulic conductivity and specific storage coefficients (U–DD), Chambers–Clover Creek watershed and vicinity, Washington. R. 05 E. T. 15 N. T. 15 N. T. 17 N. T. 18 N. T. 19 N. T. 20 N. T. 21 N. R. 04 E. R. 03 E. R. 02 E. R. 01 E. Puget Sound Lake Tapps American Lake Gravelly Lake Spanaway Lake Steilacoom Lake Ohop Lake Tanwax Lake Lake Kapowsin Swan Creek Puya llu p River C l o ver C re e k C h a m bers C r ee k Nis q ual l y R iv er N i s q u a l l y Riv e r P u y a ll u p R i v e r C a r b o n R i v e r M a s h e l Ri ver Ni sq ua ll y R iv e r M u c k C r e e k M u c k C re e k L acam a s C r e ek C l e a r C r e ek C la r k s Cr e ek Oho p C r e e k P u allup R iv er C lo v e r C r e ek S ou t h C re ek T a nwa x C re ek N. Fork C . C. S e q ua l i tc he w C r . Base from U.S. Geological Survey digital data, 1983, 1:100,000 Universal Transverse Mercator projection, Zone 10 Horizontal Datum: North American Datum of 1983 (NAD 83) 47°00° 46°50' 47°20' 30' 20' 122°10' 122°40' 10' 0 4 6 8 MILES 2 0 4 6 8 KILOMETERS 2 2.83455 to 10.00 10.01 to 20.00 20.01 to 50.00 50.01 to 100.00 100.01 to 500.00 500.01 to 4051.59900 EXPLANATION Boundary of Water Resource Inventory Area Boundary of active model Horizontal hydraulic conductivity of AL unit, in feet per day A ---PAGE BREAK--- Figure 22 67 Figure 22.—Continued R. 05 E. T. 15 N. T. 15 N. T. 17 N. T. 18 N. T. 19 N. T. 20 N. T. 21 N. R. 04 E. R. 03 E. R. 02 E. R. 01 E. Puget Sound Lake Tapps American Lake Gravelly Lake Spanaway Lake Steilacoom Lake Ohop Lake Tanwax Lake Lake Kapowsin Swan Creek Puya llu p River C l o ver C re e k C h a m bers C r ee k Nis q ual l y R iv er N i s q u a l l y Riv e r P u y a ll u p R i v e r C a r b o n R i v e r M a s h e l Ri ver Ni sq ua ll y R iv e r M u c k C r e e k M u c k C re e k L acam a s C r e ek C l e a r C r e ek C la r k s Cr e ek Oho p C r e e k P u allup R iv er C lo v e r C r e ek S ou t h C re ek T a nwa x C re ek N. Fork C . C. S e q ua l i tc he w C r . Base from U.S. Geological Survey digital data, 1983, 1:100,000 Universal Transverse Mercator projection, Zone 10 Horizontal Datum: North American Datum of 1983 (NAD 83) 47°00° 46°50' 47°20' 30' 20' 122°10' 122°40' 10' 0 4 6 8 MILES 2 0 4 6 8 KILOMETERS 2 6.57 to 10.00 10.01 to 20.00 20.01 to 50.00 50.01 to 100.00 100.01 to 500.00 500.01 to 17398.39 EXPLANATION Boundary of Water Resource Inventory Area Boundary of active model Horizontal hydraulic conductivity of A1 unit, in feet per day B ---PAGE BREAK--- 68 Numerical Simulation of the Groundwater-Flow System in the Chambers-Clover Creek Watershed Figure 22.—Continued R. 05 E. T. 15 N. T. 15 N. T. 17 N. T. 18 N. T. 19 N. T. 20 N. T. 21 N. R. 04 E. R. 03 E. R. 02 E. R. 01 E. Puget Sound Lake Tapps American Lake Gravelly Lake Spanaway Lake Steilacoom Lake Ohop Lake Tanwax Lake Lake Kapowsin Swan Creek Puya llu p River C l o ver C re e k C h a m bers C r ee k Nis q ual l y R iv er N i s q u a l l y Riv e r P u y a ll u p R i v e r C a r b o n R i v e r M a s h e l Ri ver Ni sq ua ll y R iv e r M u c k C r e e k M u c k C re e k L acam a s C r e ek C l e a r C r e ek C la r k s Cr e ek Oho p C r e e k P u allup R iv er C lo v e r C r e ek S ou t h C re ek T a nwa x C re ek N. Fork C . C. S e q ua l i tc he w C r . Base from U.S. Geological Survey digital data, 1983, 1:100,000 Universal Transverse Mercator projection, Zone 10 Horizontal Datum: North American Datum of 1983 (NAD 83) 47°00° 46°50' 47°20' 30' 20' 122°10' 122°40' 10' 0 4 6 8 MILES 2 0 4 6 8 KILOMETERS 2 0.15421 to 0.50 0.51 to 1.00 1.01 to 2.00 2.01 to 5.00 5.01 to 10.00 10.01 to 180.00 EXPLANATION Boundary of Water Resource Inventory Area Boundary of active model Horizontal hydraulic conductivity of A2 unit, in feet per day C ---PAGE BREAK--- Figure 22 69 Figure 22.—Continued R. 05 E. T. 15 N. T. 15 N. T. 17 N. T. 18 N. T. 19 N. T. 20 N. T. 21 N. R. 04 E. R. 03 E. R. 02 E. R. 01 E. Puget Sound Lake Tapps American Lake Gravelly Lake Spanaway Lake Steilacoom Lake Ohop Lake Tanwax Lake Lake Kapowsin Swan Creek Puya llu p River C l o ver C re e k C h a m bers C r ee k Nis q ual l y R iv er N i s q u a l l y Riv e r P u y a ll u p R i v e r C a r b o n R i v e r M a s h e l Ri ver Ni sq ua ll y R iv e r M u c k C r e e k M u c k C re e k L acam a s C r e ek C l e a r C r e ek C la r k s Cr e ek Oho p C r e e k P u allup R iv er C lo v e r C r e ek S ou t h C re ek T a nwa x C re ek N. Fork C . C. S e q ua l i tc he w C r . Base from U.S. Geological Survey digital data, 1983, 1:100,000 Universal Transverse Mercator projection, Zone 10 Horizontal Datum: North American Datum of 1983 (NAD 83) 47°00° 46°50' 47°20' 30' 20' 122°10' 122°40' 10' 0 4 6 8 MILES 2 0 4 6 8 KILOMETERS 2 4.227433 to 10.00 10.01 to 20.00 20.01 to 50.00 50.01 to 100.00 100.01 to 500.00 500.01 to 5,879.999000 EXPLANATION Boundary of Water Resource Inventory Area Boundary of active model Horizontal hydraulic conductivity of A3 unit, in feet per day D ---PAGE BREAK--- 70 Numerical Simulation of the Groundwater-Flow System in the Chambers-Clover Creek Watershed Figure 22.—Continued R. 05 E. T. 15 N. T. 15 N. T. 17 N. T. 18 N. T. 19 N. T. 20 N. T. 21 N. R. 04 E. R. 03 E. R. 02 E. R. 01 E. Puget Sound Lake Tapps American Lake Gravelly Lake Spanaway Lake Steilacoom Lake Ohop Lake Tanwax Lake Lake Kapowsin Swan Creek Puya llu p River C l o ver C re e k C h a m bers C r ee k Nis q ual l y R iv er N i s q u a l l y Riv e r P u y a ll u p R i v e r C a r b o n R i v e r M a s h e l Ri ver Ni sq ua ll y R iv e r M u c k C r e e k M u c k C re e k L acam a s C r e ek C l e a r C r e ek C la r k s Cr e ek Oho p C r e e k P u allup R iv er C lo v e r C r e ek S ou t h C re ek T a nwa x C re ek N. Fork C . C. S e q ua l i tc he w C r . Base from U.S. Geological Survey digital data, 1983, 1:100,000 Universal Transverse Mercator projection, Zone 10 Horizontal Datum: North American Datum of 1983 (NAD 83) 47°00° 46°50' 47°20' 30' 20' 122°10' 122°40' 10' 0 4 6 8 MILES 2 0 4 6 8 KILOMETERS 2 0.18414 to 0.50 0.51 to 1.00 1.01 to 2.00 2.01 to 5.00 5.01 to 10.00 10.01 to 11.82252 EXPLANATION Boundary of Water Resource Inventory Area Boundary of active model Horizontal hydraulic conductivity of B unit, in feet per day E ---PAGE BREAK--- Figure 22 71 Figure 22.—Continued R. 05 E. T. 15 N. T. 15 N. T. 17 N. T. 18 N. T. 19 N. T. 20 N. T. 21 N. R. 04 E. R. 03 E. R. 02 E. R. 01 E. Puget Sound Lake Tapps American Lake Gravelly Lake Spanaway Lake Steilacoom Lake Ohop Lake Tanwax Lake Lake Kapowsin Swan Creek Puya llu p River C l o ver C re e k C h a m bers C r ee k Nis q ual l y R iv er N i s q u a l l y Riv e r P u y a ll u p R i v e r C a r b o n R i v e r M a s h e l Ri ver Ni sq ua ll y R iv e r M u c k C r e e k M u c k C re e k L acam a s C r e ek C l e a r C r e ek C la r k s Cr e ek Oho p C r e e k P u allup R iv er C lo v e r C r e ek S ou t h C re ek T a nwa x C re ek N. Fork C . C. S e q ua l i tc he w C r . Base from U.S. Geological Survey digital data, 1983, 1:100,000 Universal Transverse Mercator projection, Zone 10 Horizontal Datum: North American Datum of 1983 (NAD 83) 47°00° 46°50' 47°20' 30' 20' 122°10' 122°40' 10' 0 4 6 8 MILES 2 0 4 6 8 KILOMETERS 2 0.66583 to 10.00 10.01 to 20.00 20.01 to 50.00 50.01 to 100.00 100.01 to 500.00 500.01 to 7242.48500 EXPLANATION Boundary of Water Resource Inventory Area Boundary of active model Horizontal hydraulic conductivity of C unit, in feet per day F ---PAGE BREAK--- 72 Numerical Simulation of the Groundwater-Flow System in the Chambers-Clover Creek Watershed Figure 22.—Continued R. 05 E. T. 15 N. T. 15 N. T. 17 N. T. 18 N. T. 19 N. T. 20 N. T. 21 N. R. 04 E. R. 03 E. R. 02 E. R. 01 E. Puget Sound Lake Tapps American Lake Gravelly Lake Spanaway Lake Steilacoom Lake Ohop Lake Tanwax Lake Lake Kapowsin Swan Creek Puya llu p River C l o ver C re e k C h a m bers C r ee k Nis q ual l y R iv er N i s q u a l l y Riv e r P u y a ll u p R i v e r C a r b o n R i v e r M a s h e l Ri ver Ni sq ua ll y R iv e r M u c k C r e e k M u c k C re e k L acam a s C r e ek C l e a r C r e ek C la r k s Cr e ek Oho p C r e e k P u allup R iv er C lo v e r C r e ek S ou t h C re ek T a nwa x C re ek N. Fork C . C. S e q ua l i tc he w C r . Base from U.S. Geological Survey digital data, 1983, 1:100,000 Universal Transverse Mercator projection, Zone 10 Horizontal Datum: North American Datum of 1983 (NAD 83) 47°00° 46°50' 47°20' 30' 20' 122°10' 122°40' 10' 0 4 6 8 MILES 2 0 4 6 8 KILOMETERS 2 0.28303 to 0.50 0.51 to 1.00 1.01 to 2.00 2.01 to 5.00 5.01 to 10.00 10.01 to 107.22980 EXPLANATION Boundary of Water Resource Inventory Area Boundary of active model Horizontal hydraulic conductivity of D unit, in feet per day G ---PAGE BREAK--- Figure 22 73 Figure 22.—Continued R. 05 E. T. 15 N. T. 15 N. T. 17 N. T. 18 N. T. 19 N. T. 20 N. T. 21 N. R. 04 E. R. 03 E. R. 02 E. R. 01 E. Puget Sound Lake Tapps American Lake Gravelly Lake Spanaway Lake Steilacoom Lake Ohop Lake Tanwax Lake Lake Kapowsin Swan Creek Puya llu p River C l o ver C re e k C h a m bers C r ee k Nis q ual l y R iv er N i s q u a l l y Riv e r P u y a ll u p R i v e r C a r b o n R i v e r M a s h e l Ri ver Ni sq ua ll y R iv e r M u c k C r e e k M u c k C re e k L acam a s C r e ek C l e a r C r e ek C la r k s Cr e ek Oho p C r e e k P u allup R iv er C lo v e r C r e ek S ou t h C re ek T a nwa x C re ek N. Fork C . C. S e q ua l i tc he w C r . Base from U.S. Geological Survey digital data, 1983, 1:100,000 Universal Transverse Mercator projection, Zone 10 Horizontal Datum: North American Datum of 1983 (NAD 83) 47°00° 46°50' 47°20' 30' 20' 122°10' 122°40' 10' 0 4 6 8 MILES 2 0 4 6 8 KILOMETERS 2 1.59158 to 10.00 10.01 to 20.00 20.01 to 50.00 50.01 to 100.00 100.01 to 500.00 500.01 to 2140.00 EXPLANATION Boundary of Water Resource Inventory Area Boundary of active model Horizontal hydraulic conductivity of E unit, in feet per day H ---PAGE BREAK--- 74 Numerical Simulation of the Groundwater-Flow System in the Chambers-Clover Creek Watershed Figure 22.—Continued R. 05 E. T. 15 N. T. 15 N. T. 17 N. T. 18 N. T. 19 N. T. 20 N. T. 21 N. R. 04 E. R. 03 E. R. 02 E. R. 01 E. Puget Sound Lake Tapps American Lake Gravelly Lake Spanaway Lake Steilacoom Lake Ohop Lake Tanwax Lake Lake Kapowsin Swan Creek Puya llu p River C l o ver C re e k C h a m bers C r ee k Nis q ual l y R iv er N i s q u a l l y Riv e r P u y a ll u p R i v e r C a r b o n R i v e r M a s h e l Ri ver Ni sq ua ll y R iv e r M u c k C r e e k M u c k C re e k L acam a s C r e ek C l e a r C r e ek C la r k s Cr e ek Oho p C r e e k P u allup R iv er C lo v e r C r e ek S ou t h C re ek T a nwa x C re ek N. Fork C . C. S e q ua l i tc he w C r . Base from U.S. Geological Survey digital data, 1983, 1:100,000 Universal Transverse Mercator projection, Zone 10 Horizontal Datum: North American Datum of 1983 (NAD 83) 47°00° 46°50' 47°20' 30' 20' 122°10' 122°40' 10' 0 4 6 8 MILES 2 0 4 6 8 KILOMETERS 2 1.23212 to 2.00 2.01 to 5.00 5.01 to 10.00 10.01 to 14.22439 EXPLANATION Boundary of Water Resource Inventory Area Boundary of active model Horizontal hydraulic conductivity of F unit, in feet per day I ---PAGE BREAK--- Figure 22 75 Figure 22.—Continued R. 05 E. T. 15 N. T. 15 N. T. 17 N. T. 18 N. T. 19 N. T. 20 N. T. 21 N. R. 04 E. R. 03 E. R. 02 E. R. 01 E. Puget Sound Lake Tapps American Lake Gravelly Lake Spanaway Lake Steilacoom Lake Ohop Lake Tanwax Lake Lake Kapowsin Swan Creek Puya llu p River C l o ver C re e k C h a m bers C r ee k Nis q ual l y R iv er N i s q u a l l y Riv e r P u y a ll u p R i v e r C a r b o n R i v e r M a s h e l Ri ver Ni sq ua ll y R iv e r M u c k C r e e k M u c k C re e k L acam a s C r e ek C l e a r C r e ek C la r k s Cr e ek Oho p C r e e k P u allup R iv er N o . F or k C . C. C lo v e r C r e ek S ou t h C re ek T a nwa x C re ek N. Fork C . C. S e q ua l i tc he w C r . Base from U.S. Geological Survey digital data, 1983, 1:100,000 Universal Transverse Mercator projection, Zone 10 Horizontal Datum: North American Datum of 1983 (NAD 83) 47°00° 46°50' 47°20' 30' 20' 122°10' 122°40' 10' 0 4 6 8 MILES 2 0 4 6 8 KILOMETERS 2 0.36144 to 0.50 0.51 to 1.00 1.01 to 2.00 2.01 to 5.00 5.01 to 10.00 10.01 to 408.81130 EXPLANATION Boundary of Water Resource Inventory Area Boundary of active model Horizontal hydraulic conductivity of G unit, in feet per day J ---PAGE BREAK--- 76 Numerical Simulation of the Groundwater-Flow System in the Chambers-Clover Creek Watershed Figure 22.—Continued R. 05 E. T. 15 N. T. 15 N. T. 17 N. T. 18 N. T. 19 N. T. 20 N. T. 21 N. R. 04 E. R. 03 E. R. 02 E. R. 01 E. Puget Sound Lake Tapps American Lake Gravelly Lake Spanaway Lake Steilacoom Lake Ohop Lake Tanwax Lake Lake Kapowsin Swan Creek Puya llu p River C l o ver C re e k C h a m bers C r ee k Nis q ual l y R iv er N i s q u a l l y Riv e r P u y a ll u p R i v e r C a r b o n R i v e r M a s h e l Ri ver Ni sq ua ll y R iv e r M u c k C r e e k M u c k C re e k L acam a s C r e ek C l e a r C r e ek C la r k s Cr e ek Oho p C r e e k P u allup R iv er C lo v e r C r e ek S ou t h C re ek T a nwa x C re ek N. Fork C . C. S e q ua l i tc he w C r . Base from U.S. Geological Survey digital data, 1983, 1:100,000 Universal Transverse Mercator projection, Zone 10 Horizontal Datum: North American Datum of 1983 (NAD 83) 47°00° 46°50' 47°20' 30' 20' 122°10' 122°40' 10' 0 4 6 8 MILES 2 0 4 6 8 KILOMETERS 2 0.21196 to 1.00 1.01 to 2.00 2.01 to 5.00 5.01 to 10.00 10.01 to 20.00 20.01 to 346.42880 EXPLANATION Boundary of Water Resource Inventory Area Boundary of active model Vertical hydraulic conductivity of AL unit, in feet per day K ---PAGE BREAK--- Figure 22 77 Figure 22.—Continued R. 05 E. T. 15 N. T. 15 N. T. 17 N. T. 18 N. T. 19 N. T. 20 N. T. 21 N. R. 04 E. R. 03 E. R. 02 E. R. 01 E. Puget Sound Lake Tapps American Lake Gravelly Lake Spanaway Lake Steilacoom Lake Ohop Lake Tanwax Lake Lake Kapowsin Swan Creek Puya llu p River C l o ver C re e k C h a m bers C r ee k Nis q ual l y R iv er N i s q u a l l y Riv e r P u y a ll u p R i v e r C a r b o n R i v e r M a s h e l Ri ver Ni sq ua ll y R iv e r M u c k C r e e k M u c k C re e k L acam a s C r e ek C l e a r C r e ek C la r k s Cr e ek Oho p C r e e k P u allup R iv er C lo v e r C r e ek S ou t h C re ek T a nwa x C re ek N. Fork C . C. S e q ua l i tc he w C r . Base from U.S. Geological Survey digital data, 1983, 1:100,000 Universal Transverse Mercator projection, Zone 10 Horizontal Datum: North American Datum of 1983 (NAD 83) 47°00° 46°50' 47°20' 30' 20' 122°10' 122°40' 10' 0 4 6 8 MILES 2 0 4 6 8 KILOMETERS 2 8.33 to 10.00 10.01 to 20.00 20.01 to 54.29 EXPLANATION Boundary of Water Resource Inventory Area Boundary of active model Vertical hydraulic conductivity of A1 unit, in feet per day L ---PAGE BREAK--- 78 Numerical Simulation of the Groundwater-Flow System in the Chambers-Clover Creek Watershed Figure 22.—Continued R. 05 E. T. 15 N. T. 15 N. T. 17 N. T. 18 N. T. 19 N. T. 20 N. T. 21 N. R. 04 E. R. 03 E. R. 02 E. R. 01 E. Puget Sound Lake Tapps American Lake Gravelly Lake Spanaway Lake Steilacoom Lake Ohop Lake Tanwax Lake Lake Kapowsin Swan Creek Puya llu p River C l o ver C re e k C h a m bers C r ee k Nis q ual l y R iv er N i s q u a l l y Riv e r P u y a ll u p R i v e r C a r b o n R i v e r M a s h e l Ri ver Ni sq ua ll y R iv e r M u c k C r e e k M u c k C re e k L acam a s C r e ek C l e a r C r e ek C la r k s Cr e ek Oho p C r e e k P u allup R iv er C lo v e r C r e ek S ou t h C re ek T a nwa x C re ek N. Fork C . C. S e q ua l i tc he w C r . Base from U.S. Geological Survey digital data, 1983, 1:100,000 Universal Transverse Mercator projection, Zone 10 Horizontal Datum: North American Datum of 1983 (NAD 83) 47°00° 46°50' 47°20' 30' 20' 122°10' 122°40' 10' 0.00136 to 0.00500 0.00501 to 0.01000 0.01001 to 0.02000 0.02001 to 0.05000 0.05001 to 0.10000 0.10001 to 2.49444 EXPLANATION Boundary of Water Resource Inventory Area Boundary of active model Vertical hydraulic conductivity of A2 unit, in feet per day 0 4 6 8 MILES 2 0 4 6 8 KILOMETERS 2 M ---PAGE BREAK--- Figure 22 79 Figure 22.—Continued R. 05 E. T. 15 N. T. 15 N. T. 17 N. T. 18 N. T. 19 N. T. 20 N. T. 21 N. R. 04 E. R. 03 E. R. 02 E. R. 01 E. Puget Sound Lake Tapps American Lake Gravelly Lake Spanaway Lake Steilacoom Lake Ohop Lake Tanwax Lake Lake Kapowsin Swan Creek Puya llu p River C l o ver C re e k C h a m bers C r ee k Nis q ual l y R iv er N i s q u a l l y Riv e r P u y a ll u p R i v e r C a r b o n R i v e r M a s h e l Ri ver Ni sq ua ll y R iv e r M u c k C r e e k M u c k C re e k L acam a s C r e ek C l e a r C r e ek C la r k s Cr e ek Oho p C r e e k P u allup R iv er C lo v e r C r e ek S ou t h C re ek T a nwa x C re ek N. Fork C . C. S e q ua l i tc he w C r . Base from U.S. Geological Survey digital data, 1983, 1:100,000 Universal Transverse Mercator projection, Zone 10 Horizontal Datum: North American Datum of 1983 (NAD 83) 47°00° 46°50' 47°20' 30' 20' 122°10' 122°40' 10' 0.58800 to 1.00000 1.00001 to 2.00000 2.00001 to 5.00000 5.00001 to 10.00000 10.00001 to 18.67322 EXPLANATION Boundary of Water Resource Inventory Area Boundary of active model Vertical hydraulic conductivity of A3 unit, in feet per day 0 4 6 8 MILES 2 0 4 6 8 KILOMETERS 2 N ---PAGE BREAK--- 80 Numerical Simulation of the Groundwater-Flow System in the Chambers-Clover Creek Watershed Figure 22.—Continued R. 05 E. T. 15 N. T. 15 N. T. 17 N. T. 18 N. T. 19 N. T. 20 N. T. 21 N. R. 04 E. R. 03 E. R. 02 E. R. 01 E. Puget Sound Lake Tapps American Lake Gravelly Lake Spanaway Lake Steilacoom Lake Ohop Lake Tanwax Lake Lake Kapowsin Swan Creek Puya llu p River C l o ver C re e k C h a m bers C r ee k Nis q ual l y R iv er N i s q u a l l y Riv e r P u y a ll u p R i v e r C a r b o n R i v e r M a s h e l Ri ver Ni sq ua ll y R iv e r M u c k C r e e k M u c k C re e k L acam a s C r e ek C l e a r C r e ek C la r k s Cr e ek Oho p C r e e k P u allup R iv er C lo v e r C r e ek S ou t h C re ek T a nwa x C re ek N. Fork C . C. S e q ua l i tc he w C r . Base from U.S. Geological Survey digital data, 1983, 1:100,000 Universal Transverse Mercator projection, Zone 10 Horizontal Datum: North American Datum of 1983 (NAD 83) 47°00° 46°50' 47°20' 30' 20' 122°10' 122°40' 10' 0.00099 to 0.00500 0.00501 to 0.01000 0.01001 to 0.02000 0.02001 to 0.05000 0.05001 to 0.10000 0.10001 to 2.10000 EXPLANATION Boundary of Water Resource Inventory Area Boundary of active model Vertical hydraulic conductivity of B unit, in feet per day 0 4 6 8 MILES 2 0 4 6 8 KILOMETERS 2 O ---PAGE BREAK--- Figure 22 81 Figure 22.—Continued R. 05 E. T. 15 N. T. 15 N. T. 17 N. T. 18 N. T. 19 N. T. 20 N. T. 21 N. R. 04 E. R. 03 E. R. 02 E. R. 01 E. Puget Sound Lake Tapps American Lake Gravelly Lake Spanaway Lake Steilacoom Lake Ohop Lake Tanwax Lake Lake Kapowsin Swan Creek Puya llu p River C l o ver C re e k C h a m bers C r ee k Nis q ual l y R iv er N i s q u a l l y Riv e r P u y a ll u p R i v e r C a r b o n R i v e r M a s h e l Ri ver Ni sq ua ll y R iv e r M u c k C r e e k M u c k C re e k L acam a s C r e ek C l e a r C r e ek C la r k s Cr e ek Oho p C r e e k P u allup R iv er C lo v e r C r e ek S ou t h C re ek T a nwa x C re ek N. Fork C . C. S e q ua l i tc he w C r . Base from U.S. Geological Survey digital data, 1983, 1:100,000 Universal Transverse Mercator projection, Zone 10 Horizontal Datum: North American Datum of 1983 (NAD 83) 47°00° 46°50' 47°20' 30' 20' 122°10' 122°40' 10' 0.19736 to 1.00 1.01 to 2.00 2.01 to 5.00 5.01 to 10.00 10.01 to 20.00 20.01 to 198.000 EXPLANATION Boundary of Water Resource Inventory Area Boundary of active model Vertical hydraulic conductivity of C unit, in feet per day 0 4 6 8 MILES 2 0 4 6 8 KILOMETERS 2 P ---PAGE BREAK--- 82 Numerical Simulation of the Groundwater-Flow System in the Chambers-Clover Creek Watershed Figure 22.—Continued R. 05 E. T. 15 N. T. 15 N. T. 17 N. T. 18 N. T. 19 N. T. 20 N. T. 21 N. R. 04 E. R. 03 E. R. 02 E. R. 01 E. Puget Sound Lake Tapps American Lake Gravelly Lake Spanaway Lake Steilacoom Lake Ohop Lake Tanwax Lake Lake Kapowsin Swan Creek Puya llu p River C l o ver C re e k C h a m bers C r ee k Nis q ual l y R iv er N i s q u a l l y Riv e r P u y a ll u p R i v e r C a r b o n R i v e r M a s h e l Ri ver Ni sq ua ll y R iv e r M u c k C r e e k M u c k C re e k L acam a s C r e ek C l e a r C r e ek C la r k s Cr e ek Oho p C r e e k P u allup R iv er C lo v e r C r e ek S ou t h C re ek T a nwa x C re ek N. Fork C . C. S e q ua l i tc he w C r . Base from U.S. Geological Survey digital data, 1983, 1:100,000 Universal Transverse Mercator projection, Zone 10 Horizontal Datum: North American Datum of 1983 (NAD 83) 47°00° 46°50' 47°20' 30' 20' 122°10' 122°40' 10' 0.00269 to 0.0050 0.0051 to 0.0100 0.0101 to 0.0200 0.0201 to 0.0500 0.0501 to 0.1000 0.1001 to 2.9000 EXPLANATION Boundary of Water Resource Inventory Area Boundary of active model Vertical hydraulic conductivity of D unit, in feet per day 0 4 6 8 MILES 2 0 4 6 8 KILOMETERS 2 Q ---PAGE BREAK--- Figure 22 83 Figure 22.—Continued R. 05 E. T. 15 N. T. 15 N. T. 17 N. T. 18 N. T. 19 N. T. 20 N. T. 21 N. R. 04 E. R. 03 E. R. 02 E. R. 01 E. Puget Sound Lake Tapps American Lake Gravelly Lake Spanaway Lake Steilacoom Lake Ohop Lake Tanwax Lake Lake Kapowsin Swan Creek Puya llu p River C l o ver C re e k C h a m bers C r ee k Nis q ual l y R iv er N i s q u a l l y Riv e r P u y a ll u p R i v e r C a r b o n R i v e r M a s h e l Ri ver Ni sq ua ll y R iv e r M u c k C r e e k M u c k C re e k L acam a s C r e ek C l e a r C r e ek C la r k s Cr e ek Oho p C r e e k P u allup R iv er C lo v e r C r e ek S ou t h C re ek T a nwa x C re ek N. Fork C . C. S e q ua l i tc he w C r . Base from U.S. Geological Survey digital data, 1983, 1:100,000 Universal Transverse Mercator projection, Zone 10 Horizontal Datum: North American Datum of 1983 (NAD 83) 47°00° 46°50' 47°20' 30' 20' 122°10' 122°40' 10' 0 4 6 8 MILES 2 0 4 6 8 KILOMETERS 2 0.39349 to 1.00 1.01 to 2.00 2.01 to 3.51821 EXPLANATION Boundary of Water Resource Inventory Area Boundary of active model Vertical hydraulic conductivity of E unit, in feet per day R ---PAGE BREAK--- 84 Numerical Simulation of the Groundwater-Flow System in the Chambers-Clover Creek Watershed Figure 22.—Continued R. 05 E. T. 15 N. T. 15 N. T. 17 N. T. 18 N. T. 19 N. T. 20 N. T. 21 N. R. 04 E. R. 03 E. R. 02 E. R. 01 E. Puget Sound Lake Tapps American Lake Gravelly Lake Spanaway Lake Steilacoom Lake Ohop Lake Tanwax Lake Lake Kapowsin Swan Creek Puya llu p River C l o ver C re e k C h a m bers C r ee k Nis q ual l y R iv er N i s q u a l l y Riv e r P u y a ll u p R i v e r C a r b o n R i v e r M a s h e l Ri ver Ni sq ua ll y R iv e r M u c k C r e e k M u c k C re e k L acam a s C r e ek C l e a r C r e ek C la r k s Cr e ek Oho p C r e e k P u allup R iv er C lo v e r C r e ek S ou t h C re ek T a nwa x C re ek N. Fork C . C. S e q ua l i tc he w C r . Base from U.S. Geological Survey digital data, 1983, 1:100,000 Universal Transverse Mercator projection, Zone 10 Horizontal Datum: North American Datum of 1983 (NAD 83) 47°00° 46°50' 47°20' 30' 20' 122°10' 122°40' 10' 0 4 6 8 MILES 2 0 4 6 8 KILOMETERS 2 0.01247 to 0.02 0.0201 to 0.05 0.501 to 0.10 0.1001 to 0.13631 EXPLANATION Boundary of Water Resource Inventory Area Boundary of active model Vertical hydraulic conductivity of F unit, in feet per day S ---PAGE BREAK--- Figure 22 85 Figure 22.—Continued R. 05 E. T. 15 N. T. 15 N. T. 17 N. T. 18 N. T. 19 N. T. 20 N. T. 21 N. R. 04 E. R. 03 E. R. 02 E. R. 01 E. Puget Sound Lake Tapps American Lake Gravelly Lake Spanaway Lake Steilacoom Lake Ohop Lake Tanwax Lake Lake Kapowsin Swan Creek Puya llu p River C l o ver C re e k C h a m bers C r ee k Nis q ual l y R iv er N i s q u a l l y Riv e r P u y a ll u p R i v e r C a r b o n R i v e r M a s h e l Ri ver Ni sq ua ll y R iv e r M u c k C r e e k M u c k C re e k L acam a s C r e ek C l e a r C r e ek C la r k s Cr e ek Oho p C r e e k P u allup R iv er C lo v e r C r e ek S ou t h C re ek T a nwa x C re ek N. Fork C . C. S e q ua l i tc he w C r . Base from U.S. Geological Survey digital data, 1983, 1:100,000 Universal Transverse Mercator projection, Zone 10 Horizontal Datum: North American Datum of 1983 (NAD 83) 47°00° 46°50' 47°20' 30' 20' 122°10' 122°40' 10' 0 4 6 8 MILES 2 0 4 6 8 KILOMETERS 2 0.013 to 0.020 0.021 to 0.050 0.051 to 0.100 0.101 to 0.58744 EXPLANATION Boundary of Water Resource Inventory Area Boundary of active model Vertical hydraulic conductivity of G unit, in feet per day T ---PAGE BREAK--- 86 Numerical Simulation of the Groundwater-Flow System in the Chambers-Clover Creek Watershed Figure 22.—Continued R. 05 E. T. 15 N. T. 15 N. T. 17 N. T. 18 N. T. 19 N. T. 20 N. T. 21 N. R. 04 E. R. 03 E. R. 02 E. R. 01 E. Puget Sound Lake Tapps American Lake Gravelly Lake Spanaway Lake Steilacoom Lake Ohop Lake Tanwax Lake Lake Kapowsin Swan Creek Puya llu p River C l o ver C re e k C h a m bers C r ee k Nis q ual l y R iv er N i s q u a l l y Riv e r P u y a ll u p R i v e r C a r b o n R i v e r M a s h e l Ri ver Ni sq ua ll y R iv e r M u c k C r e e k M u c k C re e k L acam a s C r e ek C l e a r C r e ek C la r k s Cr e ek Oho p C r e e k P u allup R iv er C lo v e r C r e ek S ou t h C re ek T a nwa x C re ek N. Fork C . C. S e q ua l i tc he w C r . Base from U.S. Geological Survey digital data, 1983, 1:100,000 Universal Transverse Mercator projection, Zone 10 Horizontal Datum: North American Datum of 1983 (NAD 83) 47°00° 46°50' 47°20' 30' 20' 122°10' 122°40' 10' 0 4 6 8 MILES 2 0 4 6 8 KILOMETERS 2 8.4E-4 to 2E-3 2E-3 to 5E-3 5E-3 to 1E-2 1E-2 to 2E-2 2E-2 to 5E-2 5E-2 to 1.1E-1 EXPLANATION Boundary of Water Resource Inventory Area Boundary of active model Specific storage coefficients of AL unit, as volume of water released from unit volume of aquifer per foot change of hydraulic head U ---PAGE BREAK--- Figure 22 87 Figure 22.—Continued R. 05 E. T. 15 N. T. 15 N. T. 17 N. T. 18 N. T. 19 N. T. 20 N. T. 21 N. R. 04 E. R. 03 E. R. 02 E. R. 01 E. Puget Sound Lake Tapps American Lake Gravelly Lake Spanaway Lake Steilacoom Lake Ohop Lake Tanwax Lake Lake Kapowsin Swan Creek Puya llu p River C l o ver C re e k C h a m bers C r ee k Nis q ual l y R iv er N i s q u a l l y Riv e r P u y a ll u p R i v e r C a r b o n R i v e r M a s h e l Ri ver Ni sq ua ll y R iv e r M u c k C r e e k M u c k C re e k L acam a s C r e ek C l e a r C r e ek C la r k s Cr e ek Oho p C r e e k P u allup R iv er C lo v e r C r e ek S ou t h C re ek T a nwa x C re ek N. Fork C . C. S e q ua l i tc he w C r . Base from U.S. Geological Survey digital data, 1983, 1:100,000 Universal Transverse Mercator projection, Zone 10 Horizontal Datum: North American Datum of 1983 (NAD 83) 47°00° 46°50' 47°20' 30' 20' 122°10' 122°40' 10' 0 4 6 8 MILES 2 0 4 6 8 KILOMETERS 2 7.4E-4 to 2E-3 2E-3 to 5E-3 5E-3 to 1E-2 1E-2 to 2E-2 2E-2 to 5E-2 5E-2 to 1.3E-1 EXPLANATION Boundary of Water Resource Inventory Area Boundary of active model Specific storage coefficients of A1 unit, as volume of water released from unit volume of aquifer per foot change of hydraulic head V ---PAGE BREAK--- 88 Numerical Simulation of the Groundwater-Flow System in the Chambers-Clover Creek Watershed Figure 22.—Continued R. 05 E. T. 15 N. T. 15 N. T. 17 N. T. 18 N. T. 19 N. T. 20 N. T. 21 N. R. 04 E. R. 03 E. R. 02 E. R. 01 E. Puget Sound Lake Tapps American Lake Gravelly Lake Spanaway Lake Steilacoom Lake Ohop Lake Tanwax Lake Lake Kapowsin Swan Creek Puya llu p River C l o ver C re e k C h a m bers C r ee k Nis q ual l y R iv er N i s q u a l l y Riv e r P u y a ll u p R i v e r C a r b o n R i v e r M a s h e l Ri ver Ni sq ua ll y R iv e r M u c k C r e e k M u c k C re e k L acam a s C r e ek C l e a r C r e ek C la r k s Cr e ek Oho p C r e e k P u allup R iv er C lo v e r C r e ek S ou t h C re ek T a nwa x C re ek N. Fork C . C. S e q ua l i tc he w C r . Base from U.S. Geological Survey digital data, 1983, 1:100,000 Universal Transverse Mercator projection, Zone 10 Horizontal Datum: North American Datum of 1983 (NAD 83) 47°00° 46°50' 47°20' 30' 20' 122°10' 122°40' 10' 0 4 6 8 MILES 2 0 4 6 8 KILOMETERS 2 1E-6 to 2E-6 2E-6 to 5E-6 5E-6 to 1E-5 1E-5 to 2E-5 2E-5 to 5E-5 5E-5 to 1.4E-4 EXPLANATION Boundary of Water Resource Inventory Area Boundary of active model Specific storage coefficients of A2 unit, as volume of water released from unit volume of aquifer per foot change of hydraulic head W ---PAGE BREAK--- Figure 22 89 Figure 22.—Continued R. 05 E. T. 15 N. T. 15 N. T. 17 N. T. 18 N. T. 19 N. T. 20 N. T. 21 N. R. 04 E. R. 03 E. R. 02 E. R. 01 E. Puget Sound Lake Tapps American Lake Gravelly Lake Spanaway Lake Steilacoom Lake Ohop Lake Tanwax Lake Lake Kapowsin Swan Creek Puya llu p River C l o ver C re e k C h a m bers C r ee k Nis q ual l y R iv er N i s q u a l l y Riv e r P u y a ll u p R i v e r C a r b o n R i v e r M a s h e l Ri ver Ni sq ua ll y R iv e r M u c k C r e e k M u c k C re e k L acam a s C r e ek C l e a r C r e ek C la r k s Cr e ek Oho p C r e e k P u allup R iv er C lo v e r C r e ek S ou t h C re ek T a nwa x C re ek N. Fork C . C. S e q ua l i tc he w C r . Base from U.S. Geological Survey digital data, 1983, 1:100,000 Universal Transverse Mercator projection, Zone 10 Horizontal Datum: North American Datum of 1983 (NAD 83) 47°00° 46°50' 47°20' 30' 20' 122°10' 122°40' 10' 0 4 6 8 MILES 2 0 4 6 8 KILOMETERS 2 EXPLANATION Boundary of Water Resource Inventory Area Boundary of active model 9.3E-8 to 2E-7 2E-7 to 5E-7 5E-7 to 1E-6 1E-6 to 2E-6 2E-6 to 5E-6 5E-6 to 1.4E-5 Specific storage coefficients of A3 unit, as volume of water released from unit volume of aquifer per foot change of hydraulic head X ---PAGE BREAK--- 90 Numerical Simulation of the Groundwater-Flow System in the Chambers-Clover Creek Watershed Figure 22.—Continued R. 05 E. T. 15 N. T. 15 N. T. 17 N. T. 18 N. T. 19 N. T. 20 N. T. 21 N. R. 04 E. R. 03 E. R. 02 E. R. 01 E. Puget Sound Lake Tapps American Lake Gravelly Lake Spanaway Lake Steilacoom Lake Ohop Lake Tanwax Lake Lake Kapowsin Swan Creek Puya llu p River C l o ver C re e k C h a m bers C r ee k Nis q ual l y R iv er N i s q u a l l y Riv e r P u y a ll u p R i v e r C a r b o n R i v e r M a s h e l Ri ver Ni sq ua ll y R iv e r M u c k C r e e k M u c k C re e k L acam a s C r e ek C l e a r C r e ek C la r k s Cr e ek Oho p C r e e k P u allup R iv er C lo v e r C r e ek S ou t h C re ek T a nwa x C re ek N. Fork C . C. S e q ua l i tc he w C r . Base from U.S. Geological Survey digital data, 1983, 1:100,000 Universal Transverse Mercator projection, Zone 10 Horizontal Datum: North American Datum of 1983 (NAD 83) 47°00° 46°50' 47°20' 30' 20' 122°10' 122°40' 10' 0 4 6 8 MILES 2 0 4 6 8 KILOMETERS 2 EXPLANATION Boundary of Water Resource Inventory Area Boundary of active model 7E-7 to 2E-6 2E-6 to 5E-6 5E-6 to 1E-5 1E-5 to 2E-5 2E-5 to 5E-5 5E-5 to 1.5E-4 Specific storage coefficients of B unit, as volume of water released from unit volume of aquifer per foot change of hydraulic head Y ---PAGE BREAK--- Figure 22 91 Figure 22.—Continued R. 05 E. T. 15 N. T. 15 N. T. 17 N. T. 18 N. T. 19 N. T. 20 N. T. 21 N. R. 04 E. R. 03 E. R. 02 E. R. 01 E. Puget Sound Lake Tapps American Lake Gravelly Lake Spanaway Lake Steilacoom Lake Ohop Lake Tanwax Lake Lake Kapowsin Swan Creek Puya llu p River C l o ver C re e k C h a m bers C r ee k Nis q ual l y R iv er N i s q u a l l y Riv e r P u y a ll u p R i v e r C a r b o n R i v e r M a s h e l Ri ver Ni sq ua ll y R iv e r M u c k C r e e k M u c k C re e k L acam a s C r e ek C l e a r C r e ek C la r k s Cr e ek Oho p C r e e k P u allup R iv er C lo v e r C r e ek S ou t h C re ek T a nwa x C re ek N. Fork C . C. S e q ua l i tc he w C r . Base from U.S. Geological Survey digital data, 1983, 1:100,000 Universal Transverse Mercator projection, Zone 10 Horizontal Datum: North American Datum of 1983 (NAD 83) 47°00° 46°50' 47°20' 30' 20' 122°10' 122°40' 10' 0 4 6 8 MILES 2 0 4 6 8 KILOMETERS 2 EXPLANATION Boundary of Water Resource Inventory Area Boundary of active model Specific storage coefficients of C unit, as volume of water released from unit volume of aquifer per foot change of hydraulic head 9.2E-8 to 2E-7 2E-7 to 5E-7 5E-7 to 1E-6 1E-6 to 2E-6 2E-6 to 5E-6 5E-6 to 1.5E-5 Z ---PAGE BREAK--- 92 Numerical Simulation of the Groundwater-Flow System in the Chambers-Clover Creek Watershed Figure 22.—Continued R. 05 E. T. 15 N. T. 15 N. T. 17 N. T. 18 N. T. 19 N. T. 20 N. T. 21 N. R. 04 E. R. 03 E. R. 02 E. R. 01 E. Puget Sound Lake Tapps American Lake Gravelly Lake Spanaway Lake Steilacoom Lake Ohop Lake Tanwax Lake Lake Kapowsin Swan Creek Puya llu p River C l o ver C re e k C h a m bers C r ee k Nis q ual l y R iv er N i s q u a l l y Riv e r P u y a ll u p R i v e r C a r b o n R i v e r M a s h e l Ri ver Ni sq ua ll y R iv e r M u c k C r e e k M u c k C re e k L acam a s C r e ek C l e a r C r e ek C la r k s Cr e ek Oho p C r e e k P u allup R iv er C lo v e r C r e ek S ou t h C re ek T a nwa x C re ek N. Fork C . C. S e q ua l i tc he w C r . Base from U.S. Geological Survey digital data, 1983, 1:100,000 Universal Transverse Mercator projection, Zone 10 Horizontal Datum: North American Datum of 1983 (NAD 83) 47°00° 46°50' 47°20' 30' 20' 122°10' 122°40' 10' 0 4 6 8 MILES 2 0 4 6 8 KILOMETERS 2 EXPLANATION Boundary of Water Resource Inventory Area Boundary of active model Specific storage coefficients of D unit, as volume of water released from unit volume of aquifer per foot change of hydraulic head 8E-7 to 2E-6 2E-6 to 5E-6 5E-6 to 1E-5 1E-5 to 2E-5 2E-5 to 5E-5 5E-5 to 1.8E-4 AA ---PAGE BREAK--- Figure 22 93 Figure 22.—Continued R. 05 E. T. 15 N. T. 15 N. T. 17 N. T. 18 N. T. 19 N. T. 20 N. T. 21 N. R. 04 E. R. 03 E. R. 02 E. R. 01 E. Puget Sound Lake Tapps American Lake Gravelly Lake Spanaway Lake Steilacoom Lake Ohop Lake Tanwax Lake Lake Kapowsin Swan Creek Puya llu p River C l o ver C re e k C h a m bers C r ee k Nis q ual l y R iv er N i s q u a l l y Riv e r P u y a ll u p R i v e r C a r b o n R i v e r M a s h e l Ri ver Ni sq ua ll y R iv e r M u c k C r e e k M u c k C re e k L acam a s C r e ek C l e a r C r e ek C la r k s Cr e ek Oho p C r e e k P u allup R iv er C lo v e r C r e ek S ou t h C re ek T a nwa x C re ek N. Fork C . C. S e q ua l i tc he w C r . Base from U.S. Geological Survey digital data, 1983, 1:100,000 Universal Transverse Mercator projection, Zone 10 Horizontal Datum: North American Datum of 1983 (NAD 83) 47°00° 46°50' 47°20' 30' 20' 122°10' 122°40' 10' 0 4 6 8 MILES 2 0 4 6 8 KILOMETERS 2 EXPLANATION Boundary of Water Resource Inventory Area Boundary of active model Specific storage coefficients of E unit, as volume of water released from unit volume of aquifer per foot change of hydraulic head 8.4E-8 to 2E-7 2E-7 to 5E-7 5E-7 to 1E-6 1E-6 to 2E-6 2E-6 to 5E-6 5E-6 to 1.7E-5 BB ---PAGE BREAK--- 94 Numerical Simulation of the Groundwater-Flow System in the Chambers-Clover Creek Watershed Figure 22.—Continued R. 05 E. T. 15 N. T. 15 N. T. 17 N. T. 18 N. T. 19 N. T. 20 N. T. 21 N. R. 04 E. R. 03 E. R. 02 E. R. 01 E. Puget Sound Lake Tapps American Lake Gravelly Lake Spanaway Lake Steilacoom Lake Ohop Lake Tanwax Lake Lake Kapowsin Swan Creek Puya llu p River C l o ver C re e k C h a m bers C r ee k Nis q ual l y R iv er N i s q u a l l y Riv e r P u y a ll u p R i v e r C a r b o n R i v e r M a s h e l Ri ver Ni sq ua ll y R iv e r M u c k C r e e k M u c k C re e k L acam a s C r e ek C l e a r C r e ek C la r k s Cr e ek Oho p C r e e k P u allup R iv er C lo v e r C r e ek S ou t h C re ek T a nwa x C re ek N. Fork C . C. S e q ua l i tc he w C r . Base from U.S. Geological Survey digital data, 1983, 1:100,000 Universal Transverse Mercator projection, Zone 10 Horizontal Datum: North American Datum of 1983 (NAD 83) 47°00° 46°50' 47°20' 30' 20' 122°10' 122°40' 10' 0 4 6 8 MILES 2 0 4 6 8 KILOMETERS 2 EXPLANATION Boundary of Water Resource Inventory Area Boundary of active model Specific storage coefficients of F unit, as volume of water released from unit volume of aquifer per foot change of hydraulic head 7.6E-7 to 2E-6 2E-6 to 5E-6 5E-6 to 1E-5 1E-5 to 2E-5 2E-5 to 5E-5 5E-5 to 1.5E-4 CC ---PAGE BREAK--- Figure 22 95 Figure 22.—Continued R. 05 E. T. 15 N. T. 15 N. T. 17 N. T. 18 N. T. 19 N. T. 20 N. T. 21 N. R. 04 E. R. 03 E. R. 02 E. R. 01 E. Puget Sound Lake Tapps American Lake Gravelly Lake Spanaway Lake Steilacoom Lake Ohop Lake Tanwax Lake Lake Kapowsin Swan Creek Puya llu p River C l o ver C re e k C h a m bers C r ee k Nis q ual l y R iv er N i s q u a l l y Riv e r P u y a ll u p R i v e r C a r b o n R i v e r M a s h e l Ri ver Ni sq ua ll y R iv e r M u c k C r e e k M u c k C re e k L acam a s C r e ek C l e a r C r e ek C la r k s Cr e ek Oho p C r e e k P u allup R iv er C lo v e r C r e ek S ou t h C re ek T a nwa x C re ek N. Fork C . C. S e q ua l i tc he w C r . Base from U.S. Geological Survey digital data, 1983, 1:100,000 Universal Transverse Mercator projection, Zone 10 Horizontal Datum: North American Datum of 1983 (NAD 83) 47°00° 46°50' 47°20' 30' 20' 122°10' 122°40' 10' 0 4 6 8 MILES 2 0 4 6 8 KILOMETERS 2 EXPLANATION Boundary of Water Resource Inventory Area Boundary of active model Specific storage coefficients of G unit, as volume of water released from unit volume of aquifer per foot change of hydraulic head 2.4E-7 to 5E-7 5E-7 to 1E-6 1E-6 to 2E-6 2E-6 to 5E-6 5E-6 to 4E-5 DD ---PAGE BREAK--- 96 Numerical Simulation of the Groundwater-Flow System in the Chambers-Clover Creek Watershed Figure 23. Simulated water-level altitudes and residuals for the steady-state calibration, Chambers–Clover Creek watershed and vicinity, Washington. R. 05 E. T. 15 N. T. 15 N. T. 17 N. T. 18 N. T. 19 N. T. 20 N. T. 21 N. R. 04 E. R. 03 E. R. 02 E. R. 01 E. Puget Sound Lake Tapps American Lake Gravelly Lake Spanaway Lake Steilacoom Lake Ohop Lake Tanwax Lake Lake Kapowsin Swan Creek Puya llu p River C l o ver C re e k C h a m bers C r ee k Nis q ual l y R iv er N i s q u a l l y Riv e r P u y a ll u p R i v e r C a r b o n R i v e r M a s h e l Ri ver Ni sq ua ll y R iv e r M u c k C r e e k M u c k C re e k L acam a s C r e ek C l e a r C r e ek C la r k s Cr e ek Oho p C r e e k P u allup R iv er C lo v e r C r e ek S ou t h C re ek T a nwa x C re ek N. Fork C . C. S e q ua l i tc he w C r . Base from U.S. Geological Survey digital data, 1983, 1:100,000 Universal Transverse Mercator projection, Zone 10 Horizontal Datum: North American Datum of 1983 (NAD 83) 47°00° 46°50' 47°20' 30' 20' 122°10' 122°40' 10' 0 4 6 8 MILES 2 0 4 6 8 KILOMETERS 2 EXPLANATION Boundary of Water Resource Inventory Area AL unit wells with residual value—Positive residual 2 (measured value is greater than simulated) and negative residual -1 (Measured value is less than simulated) Boundary of active model Simulated groundwater levels in hydrogeologic unit AL, in feet above NAVD 0 to 25 25 to 50 50 to 100 100 to 200 200 to 400 400 to 600 600 to 800 800 to 945 0 -3 -1 -2 -8 -6 -20 -11 -16 -16 -16 -2 -4-5 -16 -26 -11 -17 0 -3 -1 -2 -8 -6 -20 -11 -16 -16 -16 1 6 2 2 1 3 1 18 1 6 2 2 1 3 1 18 -2 -4-5 -16 -26 -11 -17 A ---PAGE BREAK--- Figure 23 97 Figure 23.—Continued -3 -7 -7 -4 -8 -21 -24 -17 -35 -12 -26 -37 -26 -4 -3 -7 -7 -4 -8 -21 -24 -17 -35 -12 -26 -37 -26 1 0 4 6 1 8 4 10 13 12 64 1 0 4 6 1 8 7 4 10 13 12 64 -4 R. 05 E. T. 15 N. T. 15 N. T. 17 N. T. 18 N. T. 19 N. T. 20 N. T. 21 N. R. 04 E. R. 03 E. R. 02 E. R. 01 E. Puget Sound Lake Tapps American Lake Gravelly Lake Spanaway Lake Steilacoom Lake Ohop Lake Tanwax Lake Lake Kapowsin Swan Creek Puya llu p River C l o ver C re e k C h a m bers C r ee k Nis q ual l y R iv er N i s q u a l l y Riv e r P u y a ll u p R i v e r C a r b o n R i v e r M a s h e l Ri ver Ni sq ua ll y R iv e r M u c k C r e e k M u c k C re e k L acam a s C r e ek C l e a r C r e ek C la r k s Cr e ek Oho p C r e e k P u allup R iv er C lo v e r C r e ek S ou t h C re ek T a nwa x C re ek N. Fork C . C. S e q ua l i tc he w C r . Base from U.S. Geological Survey digital data, 1983, 1:100,000 Universal Transverse Mercator projection, Zone 10 Horizontal Datum: North American Datum of 1983 (NAD 83) 47°00° 46°50' 47°20' 30' 20' 122°10' 122°40' 10' 0 4 6 8 MILES 2 0 4 6 8 KILOMETERS 2 EXPLANATION Boundary of Water Resource Inventory Area A1 unit wells with residual value—Positive residual 4 (measured value is greater than simulated) and negative residual -7 (Measured value is less than simulated) Boundary of active model Simulated groundwater levels in hydrogeologic unit A1, in feet above NAVD 20 to 25 25 to 50 50 to 100 100 to 200 200 to 400 400 to 600 600 to 800 800 to 948 B ---PAGE BREAK--- 98 Numerical Simulation of the Groundwater-Flow System in the Chambers-Clover Creek Watershed Figure 23.—Continued R. 05 E. T. 15 N. T. 15 N. T. 17 N. T. 18 N. T. 19 N. T. 20 N. T. 21 N. R. 04 E. R. 03 E. R. 02 E. R. 01 E. Puget Sound Lake Tapps American Lake Gravelly Lake Spanaway Lake Steilacoom Lake Ohop Lake Tanwax Lake Lake Kapowsin Swan Creek Puya llu p River C l o ver C re e k C h a m bers C r ee k Nis q ual l y R iv er N i s q u a l l y Riv e r P u y a ll u p R i v e r C a r b o n R i v e r M a s h e l Ri ver Ni sq ua ll y R iv e r M u c k C r e e k M u c k C re e k L acam a s C r e ek C l e a r C r e ek C la r k s Cr e ek Oho p C r e e k P u allup R iv er C lo v e r C r e ek S ou t h C re ek T a nwa x C re ek N. Fork C . C. S e q ua l i tc he w C r . Base from U.S. Geological Survey digital data, 1983, 1:100,000 Universal Transverse Mercator projection, Zone 10 Horizontal Datum: North American Datum of 1983 (NAD 83) 47°00° 46°50' 47°20' 30' 20' 122°10' 122°40' 10' 0 4 6 8 MILES 2 0 4 6 8 KILOMETERS 2 EXPLANATION Boundary of Water Resource Inventory Area A3 unit wells with residual value—Positive residual 5 (measured value is greater than simulated) and negative residual -2 (Measured value is less than simulated) Boundary of active model Simulated groundwater levels in hydrogeologic unit A3, in feet above NAVD 18 to 25 25 to 50 50 to 100 100 to 200 200 to 400 400 to 600 600 to 757 6 7 7 2 1 47 4713 13 19 19 84 84 26 26 18 18 29 29 10 10 44 44 34 34 11 11 45 45 44 44 16 16 -40 -40 -12 -12 -33 -33 -7-7 -90 -90 -12 -12 -1-1 -2-2 -2-2 -18 -18 -6-6 -3-3 -9-9 -5-5 -16 -16 -1-1 -55 -55 -62 -62 -16 -16 -16 -16 -16 -16 -16 -16 -16 -16 -2-2 -2-2 -14 -14 -17 -17 -38 -38 -5-5 -24 -24 -54 -54 -5-5 -19 -19 -111 -111 -2-2 -9-9 -5-5 -4-4 -50 -50 -18 -18 -36 -36 -99 -99 -29 -29 -26 -26 21 21 5 18 18 26 26 17 17 58 58 1 12 12 22 22 3 7 44 44 28 28 2 13 13 6 6 18 18 1 5 180 180 20 20 77 77 C ---PAGE BREAK--- Figure 23 99 Figure 23.—Continued R. 05 E. T. 15 N. T. 15 N. T. 17 N. T. 18 N. T. 19 N. T. 20 N. T. 21 N. R. 04 E. R. 03 E. R. 02 E. R. 01 E. Puget Sound Lake Tapps American Lake Gravelly Lake Spanaway Lake Steilacoom Lake Ohop Lake Tanwax Lake Lake Kapowsin Swan Creek Puya llu p River C l o ver C re e k C h a m bers C r ee k Nis q ual l y R iv er N i s q u a l l y Riv e r P u y a ll u p R i v e r C a r b o n R i v e r M a s h e l Ri ver Ni sq ua ll y R iv e r M u c k C r e e k M u c k C re e k L acam a s C r e ek C l e a r C r e ek C la r k s Cr e ek Oho p C r e e k P u allup R iv er C lo v e r C r e ek S ou t h C re ek T a nwa x C re ek N. Fork C . C. S e q ua l i tc he w C r . Base from U.S. Geological Survey digital data, 1983, 1:100,000 Universal Transverse Mercator projection, Zone 10 Horizontal Datum: North American Datum of 1983 (NAD 83) 47°00° 46°50' 47°20' 30' 20' 122°10' 122°40' 10' 0 4 6 8 MILES 2 0 4 6 8 KILOMETERS 2 EXPLANATION Boundary of Water Resource Inventory Area C unit wells with residual value—Positive residual 2 (measured value is greater than simulated) and negative residual -3 (Measured value is less than simulated) Boundary of active model Simulated groundwater levels in hydrogeologic unit C, in feet above NAVD 0 to 25 25 to 50 50 to 100 100 to 200 200 to 400 400 to 600 600 to 730 -1 8 7 6 1 8 3 6 2 2 3 7 19 19 61 61 12 12 17 17 18 18 11 11 0 -2-2 -2-2 -6-6 -6-6 -1 -3-3 -8-8 -9-9 -4-4 -2-2 -1-1 -3-3 -8-8 -2-2 -2-2 -4-4 -14 -14 -16 -16 -33 -33 -33 -33 -35 -35 -87 -87 -11 -11 -21 -21 -23 -23 -15 -15 -11 -11 -23 -23 -13 -13 -27 -27 -17 -17 -17 -17 -19 -19 -18 -18 -27 -27 -16 -16 -52 -52 -62 -62 -43 -43 -12 -12 -14 -14 -15 -15 -17 -17 D ---PAGE BREAK--- 100 Numerical Simulation of the Groundwater-Flow System in the Chambers-Clover Creek Watershed Figure 23.—Continued R. 05 E. T. 15 N. T. 15 N. T. 17 N. T. 18 N. T. 19 N. T. 20 N. T. 21 N. R. 04 E. R. 03 E. R. 02 E. R. 01 E. Puget Sound Lake Tapps American Lake Gravelly Lake Spanaway Lake Steilacoom Lake Ohop Lake Tanwax Lake Lake Kapowsin Swan Creek Puya llu p River C l o ver C re e k C h a m bers C r ee k Nis q ual l y R iv er N i s q u a l l y Riv e r P u y a ll u p R i v e r C a r b o n R i v e r M a s h e l Ri ver Ni sq ua ll y R iv e r M u c k C r e e k M u c k C re e k L acam a s C r e ek C l e a r C r e ek C la r k s Cr e ek Oho p C r e e k P u allup R iv er C lo v e r C r e ek S ou t h C re ek T a nwa x C re ek N. Fork C . C. S e q ua l i tc he w C r . Base from U.S. Geological Survey digital data, 1983, 1:100,000 Universal Transverse Mercator projection, Zone 10 Horizontal Datum: North American Datum of 1983 (NAD 83) 47°00° 46°50' 47°20' 30' 20' 122°10' 122°40' 10' 0 4 6 8 MILES 2 0 4 6 8 KILOMETERS 2 EXPLANATION Boundary of Water Resource Inventory Area E unit wells with residual value—Positive residual 5 (measured value is greater than simulated) and negative residual -6 (Measured value is less than simulated) Boundary of active model Simulated groundwater levels in hydrogeologic unit E, in feet above NAVD 4 to 25 25 to 50 50 to 100 100 to 200 200 to 400 400 to 600 600 to 679 11 11 27 27 -6-6 -12 -12 -10 -10 -28 -28 -13 -13 72 72 5 E ---PAGE BREAK--- Figure 23 101 Figure 23.—Continued R. 05 E. T. 15 N. T. 15 N. T. 17 N. T. 18 N. T. 19 N. T. 20 N. T. 21 N. R. 04 E. R. 03 E. R. 02 E. R. 01 E. Puget Sound Lake Tapps American Lake Gravelly Lake Spanaway Lake Steilacoom Lake Ohop Lake Tanwax Lake Lake Kapowsin Swan Creek Puya llu p River C l o ver C re e k C h a m bers C r ee k Nis q ual l y R iv er N i s q u a l l y Riv e r P u y a ll u p R i v e r C a r b o n R i v e r M a s h e l Ri ver Ni sq ua ll y R iv e r M u c k C r e e k M u c k C re e k L acam a s C r e ek C l e a r C r e ek C la r k s Cr e ek Oho p C r e e k P u allup R iv er C lo v e r C r e ek S ou t h C re ek T a nwa x C re ek N. Fork C . C. S e q ua l i tc he w C r . Base from U.S. Geological Survey digital data, 1983, 1:100,000 Universal Transverse Mercator projection, Zone 10 Horizontal Datum: North American Datum of 1983 (NAD 83) 47°00° 46°50' 47°20' 30' 20' 122°10' 122°40' 10' 0 4 6 8 MILES 2 0 4 6 8 KILOMETERS 2 EXPLANATION Boundary of Water Resource Inventory Area G unit wells with residual value—Positive residual 11 (measured value is greater than simulated) and negative residual -10 (Measured value is less than simulated) Boundary of active model Simulated groundwater levels in hydrogeologic unit G, in feet above NAVD 9 to 25 25 to 50 50 to 100 100 to 200 200 to 400 400 to 600 600 to 608 11 11 -10 -10 -15 -15 F ---PAGE BREAK--- 102 Numerical Simulation of the Groundwater-Flow System in the Chambers-Clover Creek Watershed Table 13. Wells used in model calibration, Chambers-Clover Creek watershed, Washington. [Weighting factor: Applied according to a relative scale from 1 to 10. Measurements with status: Number of measurements affected by pumping, recovering, or flowing conditions. Abbreviations: HGU, Hydrogeologic-Unit; S, synoptic measurement; M, measurements; NA, not applicable] Map No. (fig. 7) Site identification No. Local well No. HGU Weight- ing factor Type Measured groundwater altitude Simulated steady state water level Steady state residual Total measure- ments Measure- ments with status Transient target measure- ments Mean of transient weighting factors Mean of transient residuals Standard deviation of transient residuals 1 471546122265601 21N/03E-32K01 A3 10 M 226.90 205.49 21.41 18 0 17 10 22.25 3.73 2 471515122322801 20N/02E-03E01 A3 3 S 154.20 148.86 5.34 1 0 1 10 6.59 NA 4 471402122232501 20N/03E-11L01 AL 10 M 10.95 13.49 -2.54 19 0 18 10 -2.44 0.90 5 471459122314601 20N/02E-03J01 B 9 M 181.41 172.66 8.75 19 5 18 8.1 10.25 6.65 6 471338122221701 20N/03E-13C02 AL 2 S 16.94 17.81 -0.87 1 1 1 5 -0.84 NA 7 471415122283201 20N/03E-07F01 A3 3 S 223.75 207.26 16.49 1 0 1 10 12.87 NA 8 471321122224601 20N/03E-14H01 C 3 S 84.13 23.03 61.10 1 0 1 10 61.20 NA 9 471351122281001 20N/03E-07Q02 A3 10 M 224.82 212.53 12.29 17 0 17 10 12.89 2.57 10 471312122225801 20N/03E-14K01 A3 10 M 72.53 79.40 -6.87 17 0 16 10 -5.13 4.37 11 471408122312801 20N/02E-11E01 C 3 S 205.53 186.57 18.96 1 0 1 10 20.86 NA 12 471258122222501 20N/03E-13N01 D 10 M 58.74 65.17 -6.43 19 0 18 10 -5.97 1.85 13 471356122312601 20N/02E-11M01 E 10 M 209.75 182.58 27.17 20 0 19 10 29.16 5.12 14 471345122302601 20N/02E-11R03 A3 10 M 223.30 205.50 17.80 19 2 18 9.2 18.73 2.64 15 471236122200901 20N/04E-20D06 E 1 S 17.22 26.98 -9.76 1 1 1 3 -9.60 NA 16 471243122200001 20N/04E-20D01 C 2 S 30.08 22.67 7.41 1 1 1 5 7.51 NA 17 471235122205101 20N/04E-19F03 AL 2 S 24.01 22.66 1.35 1 1 1 5 1.45 NA 18 471230122195601 20N/04E-20E06 AL 1 S 28.05 22.48 5.57 1 1 1 3 5.56 NA 19 471344122311601 20N/02E-11N01 A2 10 M 218.59 192.59 26.00 19 0 18 10 27.60 2.36 20 471220122203001 20N/04E-19K04 AL 3 S 25.05 22.70 2.35 1 0 1 10 2.43 NA 21 471350122334101 20N/02E-09P02 A3 10 M 36.28 125.85 -89.57 19 1 18 9.6 -87.78 5.08 22 471148122165401 20N/04E-27B01 AL 3 S 43.83 45.48 -1.65 1 0 1 10 -1.57 NA 23 471130122145401 20N/04E-51J01 AL 10 M 63.43 62.50 0.93 19 0 18 10 1.03 1.08 24 471203122203401 20N/04E-19Q01 AL 2 S 28.81 27.17 1.64 1 1 1 5 1.76 NA 25 471125122144901 20N/04E-25M01 AL 3 S 69.28 66.04 3.24 1 0 1 10 3.29 NA 26 471115122164501 20N/04E-27J01 AL 8 M 55.72 38.18 17.54 18 18 18 5 17.51 0.01 27 471246122285101 20N/03E-19D01 C 9 M 211.20 213.41 -2.21 20 5 19 8.3 -2.11 8.38 28 471102122130501 20N/05E-31C01 AL 3 S 75.73 81.40 -5.67 1 0 1 10 -5.55 NA 29 471252122301501 20N/02E-14R01 A3 3 S 214.43 208.70 5.73 1 0 1 10 11.15 NA 30 471044122134501 20N/04E-36H03 AL 3 S 76.47 78.81 -2.34 1 0 1 10 -2.34 NA 31 471103122151401 20N/04E-35A03 AL 3 S 67.27 75.54 -8.27 1 0 1 10 -8.08 NA 32 471137122205301 20N/04E-30F01 C 10 M 85.23 98.79 -13.56 19 1 18 9.6 -13.25 0.90 33 471030122122201 20N/05E-38K01 AL 3 S 79.92 90.77 -10.85 1 0 1 10 -10.45 NA 34 471239122303901 20N/02E-23B02 A3 2 S 182.92 195.08 -12.16 1 1 1 5 -12.26 NA 35 471046122213201 20N/04E-36H04 AL 3 S 77.50 81.46 -3.96 1 0 1 10 -3.93 NA 36 471028122122901 20N/05E-38P01 AL 3 S 74.28 90.77 -16.49 1 0 1 10 -16.11 NA 37 471117122195201 20N/04E-29P03 C 2 S 55.96 88.69 -32.73 1 1 1 5 -34.16 NA ---PAGE BREAK--- Table 13 103 Table 13. Wells used in model calibration, Chambers-Clover Creek watershed, Washington.—Continued [Weighting factor: Applied according to a relative scale from 1 to 10. Measurements with status: Number of measurements affected by pumping, recovering, or flowing conditions. Abbreviations: HGU, Hydrogeologic-Unit; S, synoptic measurement; M, measurements; NA, not applicable] Map No. (fig. 7) Site identification No. Local well No. HGU Weight- ing factor Type Measured groundwater altitude Simulated steady state water level Steady state residual Total measure- ments Measure- ments with status Transient target measure- ments Mean of transient weighting factors Mean of transient residuals Standard deviation of transient residuals 38 471230122302101 20N/02E-23H08 A3 3 S 203.61 204.97 -1.36 1 0 1 10 -4.00 NA 39 471032122213001 20N/04E-35H04 E 3 S 98.04 111.39 -13.35 1 0 1 10 -12.68 NA 40 471227122302801 20N/02E-23H03 A3 10 M 200.36 202.65 -2.29 19 0 18 10 -1.65 2.17 41 471125122231001 20N/03E-26K01 A2 10 M 399.56 382.45 17.11 19 0 18 10 17.39 11.40 42 471019122213201 20N/04E-36R02 AL 10 M 77.88 83.30 -5.42 18 0 18 10 -5.42 1.26 43 471058122193901 20N/04E-32C01 C 3 S 72.71 107.30 -34.59 1 0 1 10 -34.51 NA 44 471031122160401 20N/04E-35M02 E 8 M 92.43 120.36 -27.93 9 2 8 8.3 -27.32 0.40 45 470958122124401 19N/05E-06A02 AL 3 S 78.56 95.05 -16.49 1 0 1 10 -15.65 NA 46 471009122134701 19N/04E-01A02 AL 3 S 78.93 94.56 -15.63 1 0 1 10 -15.40 NA 47 471018122150801 20N/04E-35R02 C 9 M 119.16 139.78 -20.62 14 4 13 8.4 -19.33 4.52 48 471024122151201 20N/04E-35R03 A1 10 M 275.11 261.84 13.27 20 0 19 10 15.48 0.64 49 471056122203601 20N/04E-31B01 A2 10 M 337.00 284.17 52.83 19 0 18 10 55.20 2.58 50 471009122152001 19N/04E-02B01 A3 3 S 349.25 290.86 58.39 1 0 1 10 64.43 NA 51 471051122213501 20N/03E-36H01 A3 3 S 336.67 259.43 77.24 1 0 1 10 79.82 NA 52 471203122323801 20N/02E-22N04 A3 10 M 205.23 183.17 22.06 19 0 18 10 24.81 3.42 53 471030122170301 20N/04E-34N01 C 3 S 94.74 181.29 -86.55 1 0 1 10 -83.98 NA 54 470939122132901 19N/05E-06M04 AL 3 S 83.94 100.01 -16.07 1 0 1 10 -15.92 NA 55 471148122305501 20N/02E-26C02 C 9 M 213.41 201.69 11.72 20 6 19 7.8 12.01 13.63 56 471137122304701 20N/02E-26C01 C 10 M 219.36 202.19 17.17 21 0 20 10 17.67 6.44 57 471138122300601 20N/02E-38L01 C 10 M 219.07 213.34 5.73 20 1 19 9.6 6.37 5.20 58 470937122135001 19N/04E-01J04 AL 3 S 86.20 112.56 -26.36 1 0 1 10 -25.81 NA 59 471149122325701 20N/02E-28A01 E 10 M 83.65 89.63 -5.98 20 1 19 9.6 -5.48 0.73 60 471116122292701 20N/02E-37B03 A1 3 S 226.13 216.37 9.76 1 0 1 10 12.18 NA 61 471020122222901 20N/03E-36N01 C 3 S 260.12 258.84 1.28 1 0 1 10 3.39 NA 62 471124122320901 20N/02E-41G01 E 9 M 126.51 121.51 5.00 13 1 13 9.5 4.51 1.46 63 471012122220601 19N/03E-01C02 C 10 M 270.66 262.37 8.29 17 0 16 10 9.58 1.92 64 471022122250901 20N/03E-41K01 C 10 M 243.00 254.16 -11.16 19 2 18 9.2 -10.39 2.35 65 471134122315901 20N/02E-41Q02 G 10 M 120.34 130.22 -9.88 19 0 18 10 -9.27 4.33 66 471134122320001 20N/02E-41Q01 C 10 M 152.40 168.10 -15.70 19 0 18 10 -15.18 2.83 67 470910122160401 19N/04E-11D01 A3 3 S 362.45 318.22 44.23 1 0 1 10 51.60 NA 68 471048122293501 20N/02E-37K01 C 10 M 237.06 218.60 18.46 19 0 18 10 18.77 1.40 69 471007122222702 19N/03E-01E01 A2 10 M 249.92 274.79 -24.87 17 1 16 9.6 -24.23 3.97 70 470910122160301 19N/04E-11D02 E 10 M 359.77 287.36 72.41 19 0 18 10 74.37 1.13 71 471032122292701 20N/02E-36K01 A1 10 M 236.13 235.35 0.78 22 0 21 10 1.41 0.70 72 471058122334801 20N/02E-33C01 C 10 M 98.56 131.89 -33.33 19 0 18 10 -32.53 5.67 73 471335122141501 19N/04E-13B01 AL 9 M 105.84 125.76 -19.92 12 0 11 10 -19.35 0.44 ---PAGE BREAK--- 104 Numerical Simulation of the Groundwater-Flow System in the Chambers-Clover Creek Watershed Table 13. Wells used in model calibration, Chambers-Clover Creek watershed, Washington.—Continued [Weighting factor: Applied according to a relative scale from 1 to 10. Measurements with status: Number of measurements affected by pumping, recovering, or flowing conditions. Abbreviations: HGU, Hydrogeologic-Unit; S, synoptic measurement; M, measurements; NA, not applicable] Map No. (fig. 7) Site identification No. Local well No. HGU Weight- ing factor Type Measured groundwater altitude Simulated steady state water level Steady state residual Total measure- ments Measure- ments with status Transient target measure- ments Mean of transient weighting factors Mean of transient residuals Standard deviation of transient residuals 74 471018122305701 20N/02E-35P01 G 10 M 188.93 177.77 11.16 20 0 19 10 12.23 3.78 75 471011122332101 19N/02E-04B03 E 10 M 149.93 139.00 10.93 19 0 18 10 12.67 14.44 76 470928122281501 19N/03E-06Q01 C 3 S 240.84 263.80 -22.96 1 0 1 10 -16.86 NA 77 470845122230601 19N/03E-11Q01 C 10 M 261.78 276.71 -14.93 19 0 18 10 -13.58 1.85 78 470913122293101 19N/02E-12 LT05 A1 10 M 259.94 259.78 0.16 18 0 17 10 1.32 1.34 79 470812122230301 19N/03E-14G01 C 3 S 269.01 280.48 -11.47 1 0 1 10 -5.28 NA 80 470817122235101 19N/03E-14D01 A3 3 S 283.06 283.93 -0.87 1 0 1 10 6.48 NA 81 470941122350101 19N/02E-06L01 A1 10 M 154.81 142.48 12.33 19 2 18 9.6 14.91 5.82 82 470731122181001 19N/04E-21C01 A3 10 M 255.41 295.36 -39.95 19 0 18 10 -38.36 1.70 83 470654122143601 19N/04E-24L01 A3 3 S 163.19 195.75 -32.56 1 0 1 10 -30.34 NA 84 470759122233101 19N/03E-14L02 A3 10 M 304.98 288.06 16.92 19 0 18 10 18.66 2.29 85 470840122292902 19N/02E-12 CW32C G 10 M 234.22 248.82 -14.60 17 0 16 10 -13.25 3.31 86 470839122293401 19N/02E-12 CW32A A3 10 M 263.31 266.26 -2.95 17 0 16 10 -1.59 0.72 87 470744122224001 19N/03E-14R01 C 10 M 261.51 284.82 -23.31 20 0 19 10 -21.73 6.31 88 470723122201802 19N/04E-19A01D1 A3 3 S 279.85 292.28 -12.43 1 0 1 10 -5.55 NA 89 470842122300801 19N/02E-48L01 A3 9 M 260.84 266.74 -5.90 15 0 14 10 -4.06 0.74 90 470857122333501 19N/02E-09F01 B 10 M 218.27 186.28 31.99 16 0 15 10 33.41 1.29 91 470822122275001 19N/03E-42N01 A1 9 M 280.96 284.04 -3.08 18 3 17 8.8 -2.49 0.81 92 470713122193601 19N/04E-20F02 C 10 M 282.19 287.73 -5.54 19 0 18 10 -3.94 1.70 93 470717122195801 19N/04E-20E03 C 10 M 283.23 288.74 -5.51 18 0 17 10 -3.74 1.18 94 470705122180601 19N/04E-21K01 A1 3 S 473.81 409.89 63.92 1 0 1 10 66.52 NA 95 470700122193601 19N/04E-20M01 C 3 S 292.40 292.62 -0.22 2 0 2 10 1.52 2.84 96 470813122292601 19N/02E-13 CW15D E 10 M 258.62 270.61 -11.99 16 0 15 10 -10.67 1.76 97 470813122292602 19N/02E-13 CW15C A3 10 M 265.04 273.88 -8.84 18 2 17 9.3 -7.94 3.55 98 470812122293001 19N/02E-13 CW15 A1 10 M 278.20 274.40 3.80 18 0 17 10 4.69 1.61 99 470629122163101 19N/04E-27A01 A3 10 M 392.98 365.45 27.53 20 0 18 10 30.36 3.12 100 470613122141701 19N/04E-25G02 AL 3 S 156.19 156.28 -0.09 1 0 1 10 0.30 NA 101 470730122251301 19N/03E-47Q01 C 3 S 293.23 305.84 -12.61 1 0 1 10 -9.55 NA 102 470649122192701 19N/04E-20Q02 C 10 M 294.95 303.28 -8.33 18 1 17 9.6 -6.52 2.80 103 470726122252201 19N/03E-22D05 A3 10 M 309.34 307.37 1.97 19 1 18 9.6 3.08 1.92 104 470827122273701 19N/03E-45R01 A3 10 M 283.14 298.87 -15.73 19 0 18 10 -15.01 2.51 105 470638122193701 19N/04E-29C01 A3 3 S 306.86 322.81 -15.95 1 0 1 10 -8.24 NA 106 470659122244201 19N/03E-22L01 A3 10 M 337.07 310.71 26.36 19 0 18 10 27.55 0.67 107 470543122135601 19N/04E-36A01 AL 10 M 167.63 179.02 -11.39 19 0 18 10 -11.15 0.63 108 470744122311301 19N/02E-14 DA13A A1 10 M 261.39 268.87 -7.48 18 0 17 10 -6.00 1.55 109 470721122275101 19N/03E-19 IH1C A3 10 M 297.60 302.44 -4.84 18 0 17 10 -4.21 0.28 ---PAGE BREAK--- Table 13 105 Table 13. Wells used in model calibration, Chambers-Clover Creek watershed, Washington.—Continued [Weighting factor: Applied according to a relative scale from 1 to 10. Measurements with status: Number of measurements affected by pumping, recovering, or flowing conditions. Abbreviations: HGU, Hydrogeologic-Unit; S, synoptic measurement; M, measurements; NA, not applicable] Map No. (fig. 7) Site identification No. Local well No. HGU Weight- ing factor Type Measured groundwater altitude Simulated steady state water level Steady state residual Total measure- ments Measure- ments with status Transient target measure- ments Mean of transient weighting factors Mean of transient residuals Standard deviation of transient residuals 110 470620122195401 19N/04E-29E02 A3 10 M 332.17 334.47 -2.30 18 0 17 10 -0.41 2.48 111 470537122134601 19N/04E-36A02 AL 3 S 171.15 187.95 -16.80 1 0 1 10 -15.38 NA 112 470635122221502 19N/03E-25C02D1 A3 9 M 262.30 324.39 -62.09 19 4 18 8.4 -61.31 28.80 113 470620122215101 19N/03E-25C04 A3 3 S 270.19 324.99 -54.80 1 0 1 10 -48.76 NA 114 470607122193501 19N/04E-29E11 C 3 S 342.67 340.74 1.93 1 0 1 10 9.27 NA 115 470737122310802 19N/02E-14 DA12D C 10 M 246.12 248.34 -2.22 18 0 17 10 -1.11 1.62 116 470725122295702 19N/02E-24 DA2D C 10 M 264.48 291.95 -27.47 18 0 17 10 -26.54 0.55 117 470725122295801 19N/02E-24 DA2A A1 10 M 265.97 286.53 -20.56 18 0 17 10 -19.38 0.74 118 470721122292002 19N/02E-24 CW34D A1 10 M 264.69 288.53 -23.84 18 0 17 10 -22.94 1.05 119 470721122292001 19N/02E-24 CW34C C 10 M 282.75 300.09 -17.34 18 2 17 9.3 -16.53 0.68 120 470555122195601 19N/04E-29L03 A3 3 S 349.10 350.81 -1.71 1 0 1 10 6.39 NA 121 470556122234801 19N/03E-26D01 C 10 M 336.08 325.53 10.55 20 1 19 9.6 12.02 1.31 122 470731122311801 19N/02E-42A02 A3 3 S 261.52 261.00 0.52 1 0 1 10 0.53 NA 123 470622122215001 19N/03E-25G06 C 3 S 312.47 331.15 -18.68 1 0 1 10 -14.95 NA 124 470729122314801 19N/02E-42G02 A3 10 M 254.88 251.41 3.47 19 0 18 10 6.98 1.19 125 470506122131801 19N/05E-31P03 AL 10 M 191.85 190.85 1.00 19 0 18 10 1.14 1.02 126 470531122273501 19N/04E-32A06 A3 10 M 365.61 382.61 -17.00 19 0 18 10 -14.38 5.02 127 470633122205201 19N/04E-31C03 A3 3 S 344.99 361.36 -16.37 1 0 1 10 -7.53 NA 128 470529122230701 19N/04E-32G04 A3 10 M 374.29 388.11 -13.82 19 0 18 10 -11.27 3.67 129 470711122333801 19N/02E-21 LC80DP1 C 10 M 170.51 171.07 -0.56 18 0 17 10 -0.04 1.36 130 470512122170701 19N/04E-34L03 A3 9 M 440.51 427.98 12.53 19 5 18 8.4 16.09 13.87 131 470515122170401 19N/04E-34L01 C 10 M 378.34 396.53 -18.19 19 1 18 9.6 -16.18 9.10 132 470550122222401 19N/03E-51N01 A3 10 M 341.34 357.57 -16.23 19 3 18 8.8 -14.83 7.24 133 470659122325003 19N/02E-21 LC40C B 10 M 229.76 221.95 7.81 18 0 17 10 8.37 0.52 134 470659122325102 19N/02E-21 LC40D C 10 M 182.37 198.98 -16.61 17 0 16 10 -15.82 1.08 135 470540122221901 19N/03E-36C01 A1 3 S 352.24 369.28 -17.04 1 0 1 10 -5.76 NA 136 470707122361101 19N/02E-19 LF4MW13A A1 10 M 214.41 218.03 -3.62 18 0 17 10 -3.40 0.48 137 470706122361101 19N/02E-19 LF4MW13B A3 10 M 212.33 214.69 -2.36 18 0 17 10 -2.26 0.42 138 470702122353201 19N/02E-19 LF4MW02C C 10 M 124.95 127.58 -2.63 30 0 28 10 -2.11 0.58 139 470701122353601 19N/02E-19 LF4MW02A A1 10 M 225.29 219.17 6.12 30 0 28 10 6.37 0.72 140 470701122353501 19N/02E-19 LF4MW02B A3 10 M 230.06 222.78 7.28 19 0 15 10 7.54 0.36 141 470423122170502 18N/04E-03A04D1 C 3 S 451.15 452.14 -0.99 1 0 1 10 2.71 NA 142 470525122225201 19N/03E-35H02 A1 3 S 365.12 371.88 -6.76 1 0 1 10 4.27 NA 143 470705122380501 19N/01E-23 93LF54SS C 10 M 81.31 77.97 3.34 18 0 17 10 3.69 0.47 144 470429122162002 18N/04E-03H03D1 C 3 S 453.30 480.20 -26.90 1 0 1 10 -23.07 NA 145 470620122312003 19N/02E-21 LC21C C 10 M 269.82 279.27 -9.45 18 0 17 10 -8.66 0.55 ---PAGE BREAK--- 106 Numerical Simulation of the Groundwater-Flow System in the Chambers-Clover Creek Watershed Table 13. Wells used in model calibration, Chambers-Clover Creek watershed, Washington.—Continued [Weighting factor: Applied according to a relative scale from 1 to 10. Measurements with status: Number of measurements affected by pumping, recovering, or flowing conditions. Abbreviations: HGU, Hydrogeologic-Unit; S, synoptic measurement; M, measurements; NA, not applicable] Map No. (fig. 7) Site identification No. Local well No. HGU Weight- ing factor Type Measured groundwater altitude Simulated steady state water level Steady state residual Total measure- ments Measure- ments with status Transient target measure- ments Mean of transient weighting factors Mean of transient residuals Standard deviation of transient residuals 146 470413122145301 18N/04E-01N03 A1 10 M 563.84 555.41 8.43 19 3 18 8.8 8.90 1.47 147 470619122330301 19N/02E-28 LC75D C 10 M 239.79 243.79 -4.00 18 0 17 10 -3.35 1.98 148 470605122315901 19N/02E-44 9700MW1 A1 10 M 270.34 269.47 0.87 18 0 17 10 1.64 1.27 149 470603122305101 19N/02E-26 LC149C A3 10 M 275.85 293.90 -18.05 20 0 18 10 -16.96 0.91 150 470519122241001 19N/03E-34L02 A3 3 S 366.63 360.23 6.40 1 0 1 10 12.75 NA 151 470503122240501 19N/03E-34R02 A3 10 M 372.88 366.45 6.43 19 0 18 10 8.56 1.20 152 470339122125601 18N/05E-07G04 C 3 S 644.67 696.25 -51.58 1 0 1 10 -30.22 NA 153 470343122131801 18N/05E-07F08D1 C 9 M 656.08 659.23 -3.15 11 0 11 10 -0.74 2.04 154 470343122131801 18N/05E-07F08D1 A3 8 M 853.61 673.75 179.86 6 1 6 8.8 180.07 3.45 155 470425122193001 18N/04E-05L02 A1 5 S 395.63 431.02 -35.39 3 0 4 10 -20.96 2.83 156 470416122182701 18N/04E-04P05 C 10 M1 445.41 437.52 7.89 19 19 22 5 10.51 3.67 157 470437122234702 18N/03E-02D01D1 A3 3 S 374.30 369.48 4.82 1 0 1 10 12.55 NA 158 470608122354401 19N/02E-30 LC89D1 C 10 M 131.65 129.37 2.28 18 0 17 10 2.29 0.87 159 470635122393401 19N/01E-27B01 C 3 S 60.97 55.05 5.92 1 0 1 10 4.76 NA 160 470330122133902 18N/05E-07P03D1 A3 10 M 652.72 706.49 -53.77 19 1 18 9.6 -52.24 4.32 161 470309122130701 18N/05E-18B02 C 3 S 636.84 698.58 -61.74 1 0 1 10 -50.38 NA 162 470411122213501 18N/03E-01R01 A3 1 S 363.34 401.66 -38.32 1 1 1 3 -30.40 NA 163 470304122133101 18N/05E-18D03 C 3 S 645.28 688.04 -42.76 1 0 1 10 -33.45 NA 164 470234122185901 18N/04E-17J03 A2 10 M1 477.80 499.83 -22.03 19 19 22 5 -19.82 1.52 165 470303122140901 18N/04E-13B06 A3 1 S 685.69 690.45 -4.76 1 1 1 3 9.42 NA 166 470403122224001 18N/03E-12D03 A3 3 S 383.35 382.29 1.06 1 0 1 10 7.79 NA 167 470343122203301 18N/04E-07G01 A2 10 M 409.70 422.15 -12.45 19 3 18 8.8 -9.97 3.40 168 470327122182901 18N/04E-09P03 A2 10 M1 487.47 458.76 28.71 19 19 22 5 31.26 4.42 169 470416122254101 18N/03E-04Q02 A3 10 M 381.09 362.73 18.36 19 0 18 10 19.68 1.36 170 470251122145401 18N/04E-13E04 A3 10 M 688.42 681.17 7.25 19 0 18 10 9.71 4.62 171 470249122143501 18N/04E-13F06 A3 3 S 731.84 684.79 47.05 1 0 1 10 61.28 NA 172 470221122134601 18N/05E-18N04 A3 10 M 695.92 688.46 7.46 19 3 18 8.8 9.68 3.81 173 470221122135201 18N/04E-13R03 A3 1 S 699.74 687.18 12.56 1 1 1 3 25.86 NA 174 470204122132301 18N/05E-19C05 A2 3 S 673.80 711.62 -37.82 1 0 1 10 -19.96 NA 175 470317122234101 18N/03E-11N04 A1 10 M 395.47 388.26 7.21 18 0 17 10 9.25 1.52 176 470225122165102 18N/04E-15R02D1 A3 3 S 641.44 665.10 -23.66 1 0 1 10 -9.84 NA 177 470217122163901 18N/04E-22A01 C 10 M 647.78 660.01 -12.23 20 0 19 10 -11.20 2.10 178 470337122171901 18N/04E-10F03 A3 10 M1 523.42 528.66 -5.24 19 19 21 5 -2.71 2.70 179 470501122405001 19N/01E-33Q01 C 10 M 57.66 60.11 -2.45 19 3 18 8.8 -1.91 1.08 180 470210122180701 18N/04E-21B02 A3 10 M 630.91 628.49 2.42 19 3 18 8.8 4.76 4.16 181 470208122175001 18N/04E-21A03 C 3 S 618.31 626.61 -8.30 1 0 1 10 -0.65 NA ---PAGE BREAK--- Table 13 107 Table 13. Wells used in model calibration, Chambers-Clover Creek watershed, Washington.—Continued [Weighting factor: Applied according to a relative scale from 1 to 10. Measurements with status: Number of measurements affected by pumping, recovering, or flowing conditions. Abbreviations: HGU, Hydrogeologic-Unit; S, synoptic measurement; M, measurements; NA, not applicable] Map No. (fig. 7) Site identification No. Local well No. HGU Weight- ing factor Type Measured groundwater altitude Simulated steady state water level Steady state residual Total measure- ments Measure- ments with status Transient target measure- ments Mean of transient weighting factors Mean of transient residuals Standard deviation of transient residuals 182 470240122224301 18N/03E-14J02 A3 10 M 402.14 391.65 10.49 19 0 18 10 12.38 3.02 183 470218122204601 18N/04E-19B02 A3 1 S 475.87 449.73 26.14 1 1 1 3 34.54 NA 184 470133122182801 18N/04E-21M02 A3 3 S 693.83 609.83 84.00 1 0 1 10 98.71 NA 185 470148122175201 18N/04E-21J01 C 3 S 626.71 641.70 -14.99 1 0 1 10 -7.53 NA 186 470148122205301 18N/04E-19L04 C 10 M 457.47 459.96 -2.49 19 0 18 10 -0.41 2.25 187 470418122423101 18N/01E-38R01 C 3 S 13.74 29.84 -16.10 1 0 1 10 -15.69 NA 188 470150122215301 18N/03E-24K01 A3 8 M 467.81 438.85 28.96 19 10 18 6.1 30.62 1.46 189 470146122214501 18N/03E-24K02 A3 1 S 443.43 445.33 -1.90 1 1 1 3 4.24 NA 190 470111122173601 18N/04E-27E03 A3 10 M 692.33 673.62 18.71 18 0 17 10 20.38 4.15 191 470054122162701 18N/04E-27J03 A2 3 S 707.46 684.62 22.84 1 0 1 10 37.96 NA 192 470134122215001 18N/03E-24Q03 A3 3 S 469.21 451.52 17.69 1 0 1 10 23.08 NA 193 470133122215101 18N/03E-24Q02 A3 3 S 442.67 451.50 -8.83 1 0 1 10 -3.49 NA 194 470056122190101 18N/04E-29J05 C 10 M 629.74 627.23 2.51 20 0 19 10 3.85 1.77 195 470104122251201 18N/03E-27E05 A3 1 S 388.61 393.42 -4.81 1 1 1 3 -1.49 NA 196 470114122244501 18N/03E-27L04 A1 10 M 402.80 406.39 -3.59 19 0 18 10 -2.15 5.19 197 465928122154401 17N/04E-02B01 A3 3 S 662.65 681.70 -19.05 1 0 1 10 -14.04 NA 198 465948122232801 18N/03E-35P03 C 3 S 456.81 460.68 -3.87 1 0 1 10 -0.03 NA 199 470204122401701 18N/01E-22P01 C 9 M 44.40 58.40 -14.00 18 5 17 8.5 -13.28 2.47 200 465931122224701 17N/03E-02A02 A1 3 S 460.74 486.75 -26.01 1 0 1 10 -25.32 NA 201 470033122312101 18N/02E-35D01 C 8 M 317.10 318.84 -1.74 20 12 19 5.6 -0.56 2.49 202 470013122301801 18N/02E-38 01IAMW14 A2 8 M 368.20 361.23 6.97 15 0 14 10 8.21 1.45 203 470027122324401 18N/02E-34D02 A1 10 M 303.17 299.59 3.58 19 0 18 10 4.20 1.27 204 465933122242801 17N/03E-03B02 C 10 M 451.84 445.29 6.55 19 2 18 9.2 8.57 2.71 205 465819122152301 17N/04E-11J01 A3 10 M 662.84 661.97 0.87 16 0 16 10 2.79 2.30 206 470020122312001 18N/02E-35K01 A3 3 S 326.71 344.85 -18.14 1 0 1 10 -15.18 NA 207 465923122251701 17N/03E-04H01 A1 3 S 402.50 439.71 -37.21 1 0 1 10 -31.21 NA 208 465946122293301 17N/02E-01B02 A1 3 S 374.24 386.14 -11.90 1 0 1 10 -3.93 NA 209 465956122314201 18N/02E-34R03 A2 3 S 317.83 334.05 -16.22 1 0 1 10 -13.52 NA 210 465813122190401 17N/04E-08J01 A3 3 S 532.84 644.07 -111.23 1 0 1 10 -105.53 NA 211 465903122262701 17N/03E-04N03 A3 10 M 410.31 413.88 -3.57 19 1 18 9.6 -0.86 2.73 212 465920122300501 17N/02E-01M04 C 9 M 333.12 349.89 -16.77 19 7 18 7.7 -14.98 2.48 213 465833122304001 17N/02E-11G01 A3 3 S 314.83 350.88 -36.05 1 0 1 10 -28.04 NA 214 465702122232601 17N/03E-23C02 A2 3 S 487.44 465.96 21.48 1 0 1 10 32.31 NA 215 465628122185301 17N/04E-21M01 A2 3 S 654.16 622.20 31.96 1 1 1 3 39.59 NA 216 465632122215202 17N/03E-24K08D1 A1 3 S 518.33 544.35 -26.02 1 0 1 10 -17.76 NA 217 465639122230901 17N/03E-23K01 A1 10 M 492.61 500.25 -7.64 19 0 18 10 -5.93 1.83 218 465612122183801 17N/04E-28D02 A2 10 M 606.07 596.99 9.08 19 3 18 8.8 9.61 3.47 ---PAGE BREAK--- 108 Numerical Simulation of the Groundwater-Flow System in the Chambers-Clover Creek Watershed Table 13. Wells used in model calibration, Chambers-Clover Creek watershed, Washington.—Continued [Weighting factor: Applied according to a relative scale from 1 to 10. Measurements with status: Number of measurements affected by pumping, recovering, or flowing conditions. Abbreviations: HGU, Hydrogeologic-Unit; S, synoptic measurement; M, measurements; NA, not applicable] Map No. (fig. 7) Site identification No. Local well No. HGU Weight- ing factor Type Measured groundwater altitude Simulated steady state water level Steady state residual Total measure- ments Measure- ments with status Transient target measure- ments Mean of transient weighting factors Mean of transient residuals Standard deviation of transient residuals 219 465617122213002 17N/03E-24R07D1 A3 3 S 498.39 548.22 -49.83 1 0 1 10 -39.64 NA 220 465649122324301 17N/02E-22E01 A3 10 M 330.89 319.53 11.36 19 3 18 8.8 12.99 2.46 221 465625122292301 17N/02E-24Q04 A3 3 S 428.46 384.09 44.37 1 0 1 10 55.30 NA 222 465635122311001 17N/02E-23L03 A3 3 S 383.13 348.68 34.45 1 0 1 10 43.66 NA 223 465631122322201 17N/02E-22L01 A3 1 S 345.20 325.62 19.58 1 1 1 3 26.41 NA 224 465425122265801 16N/03E-05B01 A3 10 M 586.62 541.72 44.90 19 0 18 10 49.94 12.45 225 465416122270701 16N/03E-05G03 A3 1 S 583.27 538.82 44.45 1 1 1 3 69.28 NA 226 465353122272001 16N/03E-05L01 A3 3 S 492.93 521.56 -28.63 1 0 1 10 -8.72 NA 227 465350122282601 16N/03E-06Q01 A3 3 S 344.10 443.42 -99.32 2 0 2 10 -87.61 0.56 228 465319122261801 16N/03E-09E01 A3 10 M 464.92 490.51 -25.59 19 0 18 10 -24.54 1.15 1Water-level measurements provided by Pierce County Surface Water Management Division. ---PAGE BREAK--- Publishing support provided by the U.S. Geological Survey Publishing Network, Tacoma Publishing Service Center For more information concerning the research in this report, contact the Director, Washington Water Science Center U.S. Geological Survey 934 Broadway, Suite 300 Tacoma, Washington 98402 http://wa.water.usgs.gov ---PAGE BREAK--- Johnson and others— Numerical Simulation, Groundwater-Flow System, Chambers-Clover Creek Watershed, Pierce County, WA—Scientific Investigations Report 2011–5086