Document Kennewick_doc_2fd328627c

GEOLOGIC HAZARDS ASSESSMENT AND CRITICAL AREAS REPORT PROPOSED ‘SUNRISE RIDGE’ RESIDENTIAL DEVELOPMENT ASSESOR’S PARCEL NOS.: 124892000007000 & 124893012820003 S. OLYMPIA ST. & S. NEWPORT PL., KENNEWICK, WASHINGTON GNN PROJECT NO. 216-672 FEBRUARY 2016 Prepared for DJ SUNRISE DEVELOPMENT, LLC 5602 SOUTH NEWPORT PLACE KENNEWICK, WASHINGTON 99337 Prepared by GN NORTHERN, INC. CONSULTING GEOTECHNICAL ENGINEERS KENNEWICK, WASHINGTON (509) 734-9320 (509) 248-9798 www.gnnorthern.com [EMAIL REDACTED] Common Sense Approach to Earth and Engineering Since 1995 Yakima • Kennewick • Spokane Valley • Hermiston, OR • Hood River, OR Consulting Engineers Environmental Scientists Geologists Construction Materials Testing Geophysical Services EXHIBIT 12 Page 1 of 144 ---PAGE BREAK--- At GN Northern our mission is to serve our clients in the most efficient, cost effective way using the best resources and tools available while maintaining professionalism on every level. Our philosophy is to satisfy our clients through hard work, dedication and extraordinary efforts from all of our valued employees working as an extension of the design and construction team. EXHIBIT 12 Page 2 of 144 ---PAGE BREAK--- Proposed ‘Sunrise Ridge’ Residential Dev. GNN Project No.: 216-672 S. Olympia Street, Kennewick, Washington February 25, 2016 1 February 25, 2016 GNN Project No. 216-672 DJ Sunrise Development, LLC 5602 S. Newport Place Kennewick, WA 99337 Attn: Mr. Jim Aust CC: Mr. John Fetterolf, PE, JF Engineering, PLLC Subject: Geologic Hazards Assessment & Critical Areas Report Proposed ‘Sunrise Ridge’ Residential Development Benton County APN # 124892000007000 and 124893012820003 S. Olympia Street & S. Newport Place, Kennewick, Washington Dear Mr. Aust: As requested, GN Northern, Inc. (GNN) has prepared this Geologic Hazards Assessment and Critical Areas Report to assess potential geologic hazards related to the proposed residential development property, currently identified as Benton County Assessor’s Parcels 124892000007000 and 124893012820003, generally located east of Olympia Street and west of the KID Canal in the City of Kennewick, Benton County, Washington. Based on the finding of our evaluation, we conclude that the existing geologic conditions at the site could pose potential hazards related to the proposed development if not properly mitigated. The identified geologic hazards, including erosion and slope stability, can be mitigated to acceptable levels of risk through appropriate engineering design and construction. The site is suitable for the proposed development provided the recommendations contained in this report and any subsequent site- and lot- specific design-level geotechnical engineering evaluations are followed both during the design and construction phases. The report, which follows, describes in detail our evaluation, summarizes our findings, and presents our professional opinions and recommendations. If you have any questions regarding this report, please contact us at [PHONE REDACTED]. Respectfully submitted, GN Northern, Inc. M. Yousuf Memon, EIT Staff Engineer Karl A. Harmon, LEG, PE Senior Geologist/Engineer 2017 Digitally signed by Karl A. Harmon DN: cn=Karl A. Harmon, o=GN Northern, Inc., ou, email=[EMAIL REDACTED] m, c=US Date: 2016.02.25 19:51:05 -08'00' EXHIBIT 12 Page 3 of 144 ---PAGE BREAK--- Proposed ‘Sunrise Ridge’ Residential Dev. GNN Project No.: 216-672 S. Olympia Street, Kennewick, Washington February 25, 2016 2 TABLE OF CONTENTS Page No. EXECUTIVE SUMMARY 3 INTRODUCTION 5 PROJECT DESCRIPTION 5 PROPOSED SITE GRADING & DEVELOPMENT 5 PURPOSE AND SCOPE OF SERVICES 5 METHODS OF EXPLORATION AND TESTING 7 TECHNICAL LITERATURE AND AERIAL PHOTO REVIEW 7 FIELD RECONNAISSANCE 7 FIELD EXPLORATION 7 LABORATORY TESTING 8 SOIL INFILTRATION 9 DISCUSSION 10 SITE 10 SITE HISTORY 12 SOIL CONDITIONS 12 GROUNDWATER 13 GEOLOGIC SETTING 14 GEOLOGIC HAZARDS 15 SLOPE STABILITY ANALYSIS 20 FINDINGS AND CONCLUSIONS 24 RECOMMENDATIONS 28 SITE DEVELOPMENT – GRADING 28 GRADED SLOPE CONSTRUCTION 29 SLOPE MAINTENANCE AND EROSION PROTECTION 33 REFERENCES 35 ADITIONAL SERVICES 36 LIMITATIONS OF THE GEOHAZARDS ASSESSMENT & CRITICAL AREAS REPORT 37 APPENDICES APPENDIX I – FIGURES, MAPS, & FENCE DIAGRAMS APPENDIX IV – SITE & EXPLORATION PHOTOGRAPHS APPENDIX II – EXPLORATORY BORING AND TEST-PIT LOGS APPENDIX III – LABORATORY TESTING RESULTS APPENDIX V – SLOPE STABILITY ANALYSES APPENDIX VI – HISTORIC AERIAL PHOTOGRAPHS APPENDIX VII – FEMA FLOOD MAP APPENDIX VIII – NRCS SOIL SURVEY APPENDIX IX – WASHINGTON DEPARTMENT OF ECOLOGY WELL LOG APPENDIX X – PRELIMINARY GRADING PLAN EXHIBIT 12 Page 4 of 144 ---PAGE BREAK--- Proposed ‘Sunrise Ridge’ Residential Dev. GNN Project No.: 216-672 S. Olympia Street, Kennewick, Washington February 25, 2016 3 EXECUTIVE SUMMARY GN Northern, Inc. has prepared this executive summary solely to provide a general overview of the report. The report itself should be relied upon for information about the findings, conclusions, recommendations, and other concerns. The intent of this report is to assess various geologic hazards that may impact the proposed development and provide our recommendations for mitigation. Our site evaluation has been prepared in general accordance with the requirements of the City of Kennewick’s Critical Areas Ordinance No. 5206, Chapters 18.58 and 18.62. This report does not constitute a geotechnical engineering report for development of the proposed residential subdivision at the project site. We understand the client intends to develop the subject property with a proposed residential subdivision. Future improvements at the site will include construction of new roadways, subdivision infrastructure, and site grading to develop individual residential lots. The subject property currently consists of undeveloped hillside terrain with a moderate to dense growth of native grasses and brush. Portions of the project site are mapped within the City of Kennewick’s Critical Areas for geologic hazards consisting of Steep Slopes and Erosion Hazard due to potentially erodible soils. Our site assessment was performed to identify common geologic conditions in the project region, including general and site-specific soil and bedrock conditions, groundwater, slopes, drainage, erosion, and geologic hazards. A review of selected information pertaining to the subject property and surrounding region was performed that included published technical literature, published geologic maps, available aerial photographs, and previous geotechnical/geologic studies prepared for this and other sites in the vicinity. Site-specific geologic and geotechnical data was obtained from our field exploration program consisting of nine exploratory soil borings and fourteen (14) test-pits to observe the subsurface soil conditions and obtain samples for laboratory testing. Based on our review and knowledge of the history of the site, and the findings of our subsurface exploration, it is clear that significant volumes of imported fill materials have been placed at the site. GN Northern prepared a Critical Areas Report along with a Grading Plan for placement of engineered fill over a portion of the project site relating to the adjacent Olympia Street improvements in 2014. Excess cut materials from the roadway widening project were transported EXHIBIT 12 Page 5 of 144 ---PAGE BREAK--- Proposed ‘Sunrise Ridge’ Residential Dev. GNN Project No.: 216-672 S. Olympia Street, Kennewick, Washington February 25, 2016 4 to the site and placed as controlled engineered fill under GNN’s review. While the referenced fill placement from 2014 was tested and documented, some of the deeper fill materials encountered in our explorations included large volumes of miscellaneous trash and debris, and indications that the materials were not placed as competent engineered fill. Surface conditions and grades at the site have historically been notably altered from their native conditions, with indications of additional site grading activities after completion of the referenced placement of engineered fill in 2014. Development on sloping ground poses an inherent risk related to global and local stability of site slopes. Our evaluation revealed that slope conditions at selected areas of the site do not meet typically recommended minimum factors of safety for stability. Additionally, selected areas with indications of ongoing surface erosion concerns were observed across the site, particularly in relation to the noted alterations of the native surface conditions. The proposed project development will require appropriate design and construction for both existing and proposed reconfigured slopes as well as drainage/erosion control measures to mitigate the observed geologic site constraints. The subject property is situated in an area where sheet flow and erosion may occur and near- surface site soils are known to exhibit a moderate to severe risk for erosion. Erosion concerns will require mitigation with appropriate best management practices (BMPs), including proper drainage design as well as collection and disposal (conveyance) of water to approved points of discharge in a non-erosive manner. In our professional opinion, the proposed project may be constructed as planned, provided that the recommendations in this report and any subsequent geotechnical engineering investigation(s)/evaluation(s) are incorporated in the final design and construction. Based on our site evaluation and analysis, the existing native slope conditions are relatively stable, however historically altered fill slopes and proposed cut and fill slopes for the planned development will require mitigation and remedial grading measures as recommended within this report to minimize the risk of slope instability and increase safety factors of the reconfigured slopes. Additionally, based on our evaluation, near surface site soils will not be subject to a significant threat of erosion, provided that the recommendations within this report and any subsequent geotechnical engineering report are incorporated during site grading operations along with appropriate project design, construction, and maintenance. EXHIBIT 12 Page 6 of 144 ---PAGE BREAK--- Proposed ‘Sunrise Ridge’ Residential Dev. GNN Project No.: 216-672 S. Olympia Street, Kennewick, Washington February 25, 2016 5 INTRODUCTION Project Description This Geologic Hazards Assessment and Critical Areas Report has been prepared for the site of the proposed Sunrise Ridge residential subdivision project to be developed west of the Kennewick Irrigation District - Division Four Canal (KID), and east of S. Olympia Street near the intersection with S. Newport Place, in the City of Kennewick, Benton County, Washington. Portions of the the subject property lie within the City of Kennewick – Critical Areas Map - Geologically Hazardous Areas Map, with selected areas mapped for steep slopes and erosion hazards. We understand that the proposed Sunrise Ridge residential development will include new roadways, subdivision utility & infrastructure improvements, and individual lots for future construction of single-family homes. Proposed Site Grading & Development Based on a review of the preliminary grading plans (Appendix X) prepared by JF Engineering, PLLC (dated February 18, 2016), we understand that a residential subdivision development is ultimately proposed at the project site. Proposed plans show 44 graded residential lots, along with associated roadways and infrastructure. Site development will include clearing and grubbing of vegetation, as well as significant site grading including cuts and fills throughout the project site. Majority of the southern and west- central portions of the site will include cut grading, with fill grading in the south-central and eastern & northern portions of the site along the KID canal. Proposed grading for the residential lots ranges from cut/fill grading to create relatively level areas, to constructing 2H:1V cut and fill slopes as tall as 22 and 38 feet, respectively. As depicted on the current preliminary grading plans, individual residential lots and portions along the width of the proposed roadways will be constructed with partial cut and partial fill grading. Purpose and Scope of Services The purpose of our services was to evaluate the surface and subsurface soil and bedrock conditions and potential geologic hazards as they relate to the proposed development and provide professional opinions and recommendations for mitigations of any identified geologic hazards and constraints. The scope of work included the following: EXHIBIT 12 Page 7 of 144 ---PAGE BREAK--- Proposed ‘Sunrise Ridge’ Residential Dev. GNN Project No.: 216-672 S. Olympia Street, Kennewick, Washington February 25, 2016 6 ¾ A detailed reconnaissance of the site; ¾ Subsurface exploration by excavating fourteen (14) exploratory test-pits and drilling nine soil borings; ¾ Soil infiltration testing at five locations; ¾ Laboratory testing of selected soil samples obtained from exploratory borings and test-pits; ¾ A review of selected published technical literature pertaining to the site and previous geotechnical/geologic reports prepared for similar projects in the vicinity; ¾ Review of selected available historic aerial photos and USGS topographic maps of the project site and vicinity; ¾ A geologic/engineering analysis and evaluation of the acquired data from the exploration and testing programs; ¾ Stability analyses of existing and proposed site slopes; ¾ A summary of our findings and recommendations in this written report. This report contains the following: ¾ Discussions on subsurface soil, bedrock and groundwater conditions; ¾ Discussions on regional and local geologic conditions; ¾ Discussions on geologic and seismic hazards; ¾ Graphic and tabulated results of laboratory tests and field studies; ¾ Recommendations regarding site development and grading criteria including cut and fill slope construction. Not Contained in This Report: Although available through GN Northern, the current scope of our services does not include: ¾ Site-specific geotechnical engineering evaluation or recommendations for future proposed residential structures or associated subdivision infrastructure improvements beyond the proposed initial mass grading and mitigation of geologic hazard at the site; ¾ An environmental assessment; ¾ An investigation for the presence or absence of wetlands, hazardous or toxic materials in the soil, surface water, groundwater, or air on, below, or adjacent to the subject property. EXHIBIT 12 Page 8 of 144 ---PAGE BREAK--- Proposed ‘Sunrise Ridge’ Residential Dev. GNN Project No.: 216-672 S. Olympia Street, Kennewick, Washington February 25, 2016 7 METHODS OF EXPLORATION AND TESTING Technical Literature and Aerial Photo Review A review of selected information pertaining to the site and surrounding area was performed that included published technical literature, published geologic maps, aerial photographs and previous geotechnical and geologic reports prepared for this and other sites in the vicinity. The review was performed to identify typical geotechnical and geologic constraints that may affect the proposed development, including soil and bedrock conditions, groundwater, slopes, drainage, erosion, and geologic hazards. Field Reconnaissance Field reconnaissance of the subject property was initially performed on January 29, 2016 and again in conjunction with our subsurface exploration on February 3 & 4, 2016 to observe the on-site surficial geologic and geotechnical conditions and to confirm the data obtained from our technical literature review. Field Exploration Field exploration was completed on February 3 & 4, 2016. A utility clearance was obtained prior to our field exploration. Nine exploratory borings and five infiltration test-hole were drilled; borings to depths of approximately 22.5 to 46.5 feet BGS, and infiltration test-holes to approximately 11.5 to 18.5 feet BGS. The exploratory borings were drilled using a BK 81 truck- mounted drill rig operated by Haz-Tech Drilling, Inc. Additionally, fourteen (14) exploratory test- pits, extending to depths of approximately 10 to 18 feet BGS, were excavated at the site. The exploratory test-pits were excavated with a John Deere 220C excavator operated by E-mac Corporation. The borings and test-pits were logged by a GNN field geologist/engineer. Upon completion, the borings were backfilled in general accordance with the Washington State guidelines and the test-pits were loosely backfilled with the excavated soils. Boring and test-pit locations are shown on Site Exploration Plan (Figure 7, Appendix Samples were obtained from the test borings using a Standard Penetration (SPT) sampler. The SPT sampler has a 2-inch outside diameter and a 1.38-inch inside diameter. Samples were obtained by driving the sampler with a 140-pound automatic hammer, dropping 30 inches in general accordance with ASTM D1586. The number of blows required to advance the samplers through EXHIBIT 12 Page 9 of 144 ---PAGE BREAK--- Proposed ‘Sunrise Ridge’ Residential Dev. GNN Project No.: 216-672 S. Olympia Street, Kennewick, Washington February 25, 2016 8 each 6-inch increment is recorded in the field. The SPT resistance, or N-value, is defined as the number of blows required to drive the sampler from 6 inches to 18 inches below the auger tip, with the value reported as the number of blows per one foot of penetration. The SPT N-value, adjusted for hammer efficiency and sampler size, provides an indication of the relative density or consistency of the soil and is indicated on the boring logs. Recovered soil samples were sealed in containers and returned to our laboratory. The soils observed during our field exploration were classified according to the Unified Soil Classification System (USCS), utilizing the field classification procedures as outlined in ASTM D2488. A copy of the USCS Classification Chart is included in Appendix II. Photographs of the site are presented in Appendix IV following this report. Depths referred to in this report are relative to the existing ground surface elevation at the time of our investigation. The surface and subsurface conditions described in this report are as observed at the time of our field investigation. Laboratory Testing Representative samples of the native soil obtained in the field during our subsurface exploration were selected for testing to determine the engineering and physical properties of the soils in general accordance with ASTM procedures. The following laboratory tests were performed: Table 1: Laboratory Tests Performed Test To determine Particle Size Distribution (ASTM D6913) Soil classification based on proportion of sand, silt, and clay-sized particles Natural Moisture Content (ASTM D2216) Soil moisture content indicative of in-situ condition at the time samples were taken Result of the laboratory tests are included on the boring and test-pit logs and also presented in graphic form in Appendix III attached to the end of the report. EXHIBIT 12 Page 10 of 144 ---PAGE BREAK--- Proposed ‘Sunrise Ridge’ Residential Dev. GNN Project No.: 216-672 S. Olympia Street, Kennewick, Washington February 25, 2016 9 SOIL INFILTRATION TESTING Five infiltration tests were conducted in general accordance with the EPA falling head method. The test was performed using a 3.5-inch diameter perforated HDPE pipe placed within the augered boreholes drilled to depths of approximately 11.5 to 18.5 feet BGS. Infiltration test locations are shown on Site Exploration Plan (Figure 7, Appendix I) Pea gravel was backfilled in the annulus of the test hole. The test holes were filled with water and allowed to presoak prior to the testing. Timed measurements of the drop in water level were taken within the test hole until a stabilized rate was established. The test results are indicative of the infiltration characteristic of the unique sub-soils encountered at the test depth interval. The following table presents the results of the infiltration test performed at the site: Table 2: Infiltration Test Results Test- Hole ID Approx. GPS Coordinates Test Depth (feet) Field Soil Infiltration Rate (inch/hour) Observed Soil Profile within Test-Hole P-1 46° 9' 45.16" N 119° 8' 5.36" W 13.5 16 0' - 9.5' silt/fine-grained sand 9.5' - 11.5' silty/sandy gravel 11.5' - 13.5' very dense well-graded sand P-2 46° 9' 41.23" N 119° 8' 0.78" W 11.5 32 0' - 11.5' medium-dense silt with sand P-3 46° 9' 39.53" N 119° 8' 0.78" W 15 24 0' - 10' silt with sand 10' - 15' poorly graded sand/silty sand P-4 46° 9' 35.62" N 119° 8' 5.43" W 18.5 44 0' - 3.5' apparent fill with organics 3.5' - 11' apparent trash/debris layer 11' - 18.5' loose fine silty sand P5 46° 9' 31.79" N 119° 8' 6.03" W 15 12 0' - 2' apparent fill 2' - 13' silty gravel 13' - 15' silt with trace gravel Due to the variability of the onsite materials including significant areas of existing fill, in our opinion the lowest infiltration rate (12 inches/hour), with an appropriate factor of safety, may be used for the native silty soils. For final design of the stormwater infiltration facilities, we recommend performing location- and depth-specific infiltration testing, following completion of site grading, to fully analyze the infiltration characteristics of the onsite material. EXHIBIT 12 Page 11 of 144 ---PAGE BREAK--- Proposed ‘Sunrise Ridge’ Residential Dev. GNN Project No.: 216-672 S. Olympia Street, Kennewick, Washington February 25, 2016 10 DISCUSSION Site Conditions The project site is located west of the KID Division Four Canal and east of S. Olympia Street near the intersection with S. Newport Place Owens Road), in the City of Kennewick, Benton County, Washington. The undeveloped site is currently identified by the Benton County Assessor as parcel numbers: 124892000007000 and 124893012820003. The irregular-shaped site is generally bound by the KID canal to the northeast, undeveloped land to the east and south, and single family residences to the west and southeast. The site is located in the SW ¼ of the NW ¼, and the NW ¼ of the SW ¼, of Section 24, Township 8 North and Range 29 East of the Willamette Meridian, in Benton County, Washington. Site location is shown on Site Vicinity Map (Figure 1, Appendix I) Based on site-specific topography, current site elevations within the project boundary range from approximately 845 in the southwestern portion near S. Olympia Street, to 670 feet in the northern portion near the KID canal. A local southwest-northeast trending valley (previously mapped by USGS with an intermittent stream) pre-exists at the site, extending from the southern end of the site to the eastern portion near the arched inflection of the KID canal. Native (un-altered) hillside slopes exist in the northern, western, southwestern, and southeastern portions of the project site. Surface conditions across the native hillside slopes include a moderate to dense growth of native grass and brush. Native slope gradients at the site generally range from approximately 10% to 33% in the northern and western portions, and approximately 10% to 29% across the southeastern and southwestern slopes (see Figure 3 in Appendix I for slope gradients). Based on our review and knowledge of the history of the site, and the findings of our subsurface exploration, it is clear that significant volumes of imported fill materials have been placed at the site. Surface conditions and grades in the disturbed areas at the site have been notably altered from their native conditions. It appears that the majority of the central portion of this local valley has been infilled, as well as a strip along the existing access road extending northward and a section extending up the slope southward, with imported artificial (un-controlled) fill materials. The noted fills are estimated to be as great 40 feet in depth in the central portion of the site (see Figure 6 in Appendix I for the approximate aerial extent and depths of noted fills). A recent oblique aerial image captured from Google Earth below (image looking south) shows the current site conditions near central portion of the site: EXHIBIT 12 Page 12 of 144 ---PAGE BREAK--- Proposed ‘Sunrise Ridge’ Residential Dev. GNN Project No.: 216-672 S. Olympia Street, Kennewick, Washington February 25, 2016 11 Based on the findings of our subsurface exploration of the site, fill materials were observed to include miscellaneous trash and construction debris including concrete rubble, asphalt, wood, and metal. While the upper fill layer in the central portion of the site was properly placed in 2014 per GNN’s Grading Plan (dated 10/30/2013) as engineered fill with associated testing and inspection, the underlying soils consisted of un-controlled and undocumented fill materials. Existing fill slopes at the site were noted to be as steep as 50% (2H:1V). It is apparent that some additional fill placement and miscellaneous site grading has occurred at the site following the referenced engineered fill placement in 2014. A recently constructed access road was noted to have been graded/cut through the southeastern portion of the engineered fill area. It shall be noted that the site-specific topography provided by JF Engineering does not include this recent grading. It is presumed that cut soils from this relatively recent grading activity were transported and placed over the eastern-most fill slope along the project boundary. Notable site features also included minor basins (low areas) with moist surface conditions, and areas of apparent soil erosion. Apparent rill and gully erosion, caused by the concentration of surface runoff, was noted along fill slopes in the eastern portion of the site and along the existing access road. Construction debris was noted in the northern portion of the site along the existing access road, including stockpiled soils, and metal, wood, and masonry building materials. EXHIBIT 12 Page 13 of 144 ---PAGE BREAK--- Proposed ‘Sunrise Ridge’ Residential Dev. GNN Project No.: 216-672 S. Olympia Street, Kennewick, Washington February 25, 2016 12 Photographs of the noted site features are included in Appendix IV, along with an Existing Visible Features Plan (Figure 5) included in Appendix I. Site History A review of selected available historic aerial photographs (Appendix VI) and USGS topographic maps indicate that the project site has been significantly altered form its native conditions. The 1952 photo shows the site and vicinity in its native condition before construction of the KID canal. The photo from 1988 shows the site vicinity developed with the canal and adjacent homes along Olympia Street, as well as preliminary pioneering of the northern access roadway to the site parallel to the canal. Published USGS maps of the site vicinity (Kennewick Quadrangle) depict an incised valley crossing the site from southwest to northwest with a blue-line intermittent stream terminating at the KID canal. Aerial photos from 1996 to current day show indication of ongoing filling and grading activities at the site that have resulted in significant infilling of the pre-existing natural drainage valley. Fill material appears to have been placed by dumping side-cast fill over the advancing slope face, as seen in an oblique aerial image captured from Bing Maps below: Aside from the noted controlled fill placement in 2014, we are unaware of any documentation indicating that the fill materials were placed as engineered fill. Soil Conditions Based on our subsurface exploration and the results of laboratory testing, along with our previous knowledge regarding grading activities at the site, subsurface soils consist of areas of EXHIBIT 12 Page 14 of 144 ---PAGE BREAK--- Proposed ‘Sunrise Ridge’ Residential Dev. GNN Project No.: 216-672 S. Olympia Street, Kennewick, Washington February 25, 2016 13 undocumented fill, along with an area of recently placed engineered fill atop the undocumented fill material. Undocumented and uncontrolled fill materials were found to contain roots, organic matter, asphalt, concrete and brick debris, and miscellaneous trash. The uncontrolled fill materials were encountered to depths as great as approximately 37 feet BGS, and were found to range from ‘very loose’ to ‘very dense’. Native near-surface native soils across the site were primarily classified as Silt with Sand (ML) generally underlain by Silty Gravels (GM) and weathered bedrock at depth. The upper silty soils were noted to be ‘loose’ to ‘medium dense’, transitioning to ‘dense’ with the presence of ash and cementation at deeper elevations. Layers of Sandy Silt (ML) and some fine-grained Silty Sand (SM) were noted within the upper silty unit in the northern and western portions of the site. Deeper borings along the eastern and southeastern portions of the site encountered silty gravel soils underlying the silty material. Test-pits excavated within the native site slopes in the northern, southeastern and southwestern portions revealed gravelly soils at depths ranging from approximately 9 to 15 feet BGS. Highly weathered surface of the bedrock was encountered in boring B-7, drilled at the toe of the native hillside in the southwestern portion of the site, at approximately 17.5 feet BGS. Boring and test-pit logs provided in Appendix II include more detailed descriptions of the soils encountered. Fence diagrams created using the subsurface data are attached in Appendix I. Although altered by previous grading activities and the placement of artificial fills, the soil survey map of the vicinity prepared by the Natural Resources Conservation Service (NRCS) indicates native soils in the vicinity of the project site are primarily mapped as Warden silt loam (WdAB & WdE3) situated on slopes ranging from 0 to 30%. The typical soil profile is described to consist of a relatively thin upper layer (less 12 inches) of silt loam over stratified very fine sandy loam to silt loam. The landform setting is identified as terraces and parent materials are described as loess over lacustrine deposits. Refer to the NRCS Soil Survey Map in Appendix VIII for more details. Groundwater Free groundwater was not encountered in any of our exploratory borings or test-pits within the maximum depths of exploration. To assist in our evaluation, we have reviewed the Washington State Department of Ecology (DOE) database of nearby well logs to estimated groundwater levels EXHIBIT 12 Page 15 of 144 ---PAGE BREAK--- Proposed ‘Sunrise Ridge’ Residential Dev. GNN Project No.: 216-672 S. Olympia Street, Kennewick, Washington February 25, 2016 14 in the vicinity. Based on our review of a single nearby well log, groundwater levels are anticipated to at depths greater than 100 feet BGS in the vicinity of the site; well log included in Appendix IX. Geologic Setting Regional Geology: The City of Kennewick lies on the Columbia Plateau, a broad plain situated between the Cascade Range to the west and the Rocky Mountains to the east. The Columbia Plateau was formed by a thick sequence of Miocene Age tholeiitic basalt flows, called the Columbia River Basalt Group (CRBG), which erupted from fissures in north central and northeastern Oregon, eastern Washington, and Western Idaho approximately 12 to 26 million years ago. The Columbia Plateau is often called the Columbia Basin because it forms a broad lowland surrounded by mountains. The CRBG is underlain by continental sedimentary rocks from early in the Tertiary Period. The Pliocene Age Ringold formation sediments overlie the Columbia basalts. The Ringold Formation sediments consist of a heterogeneous mix of variably cemented and compacted gravel, sand, silt, and clay deposited by the ancestral Columbia, Snake, and Yakima Rivers. The project site is generally located near the base of the Horse Heaven Hills and in line with the Rattlesnake Hills (fault/fold structure) of the Yakima Fold Belt within the vast Columbia Basin physiographic province of southeastern Washington. The Rattlesnake and Horse Heaven Hills each consist of east-west trending anticline ridges of the Yakima Fold Belt formed by north–south compression in the regional lava flows. Near the end of the Pleistocene, the Columbia Basin was subjected to a series of incredibly massive, high energy floods known as the Missoula Floods. During this time, a lobe of the Cordilleran ice sheet extended south into Idaho, damming up the Clark Fork River and creating Glacial Lake Missoula, impounding as much as 500 cubic miles of water. These ice dams periodically failed and then reformed numerous times during this period, draining the lake suddenly and unleashing a series of massive torrents of water that significantly scoured and altered landscapes in the Columbia Basin including significant erosion and deposition. Local Geology: In the Tri-Cities area the uppermost layers of the CRBG are fractured bedrock of the Wanapum Basalt formation. Regionally, the top surface of the Wanapum Basalt is known to EXHIBIT 12 Page 16 of 144 ---PAGE BREAK--- Proposed ‘Sunrise Ridge’ Residential Dev. GNN Project No.: 216-672 S. Olympia Street, Kennewick, Washington February 25, 2016 15 slope to the northeast toward the Columbia River, although local variations exist in the area. The highly weathered upper surface of the local basalt bedrock was apparently encountered at an approximate depth of 17.5 feet BGS within boring B-7 drilled near the southwest, relatively elevated portion of the site. No indications of the buried bedrock surface were noted within any of the other points of exploration throughout the site to the maximum depths explored. Overlying sediments in the project area consist of surficial deposits of Plio-Pleistocene loess, including silt and fine-grained sands, along with localized areas of Quaternary alluvium and a sequence of Pleistocene-age outburst flood deposits, commonly identified as the Missoula Flood Deposits. These deposits generally include boulder and cobble to granule-sized basaltic gravel, with lesser deposits of sand, silt, and non-basaltic gravel. GEOLOGIC HAZARDS Seismic Conditions: The Tri-Cities area is generally not considered to be located within an area of high seismic activity. There are no confirmed major faults in the Tri-Cities region capable of producing strong earthquakes. Anticipated ground motions in the region due to seismic activity along faults in other parts of the Northwest are relatively low. The seismic hazard in the project area and vicinity results from three seismic sources: interplate events, intraslab events, and crustal events (Geomatrix, 1995, 1996). Each of these events has different causes and therefore produces earthquakes with different characteristics peak ground accelerations, response spectra, and duration of strong shaking). Each is capable of generating a peak ground acceleration (pga) on rock larger than 0.05g. Two of the potential seismic sources, interplate and intraslab events, are related to the subduction of the Juan De Fuca plate beneath the North American plate. Interplate events occur due to movement at the interface of these two tectonic plates. Intraslab events originate within the subducting tectonic plate, away from its edges, when built-up stresses within the subducting plate are released. These source mechanisms are referred to as the Cascadia Subduction Zone (CSZ) source mechanism. The CSZ originates off the coast of Oregon and Washington and subducts beneath both states. EXHIBIT 12 Page 17 of 144 ---PAGE BREAK--- Proposed ‘Sunrise Ridge’ Residential Dev. GNN Project No.: 216-672 S. Olympia Street, Kennewick, Washington February 25, 2016 16 Earthquakes caused by movements along crustal faults, generally in the upper 10 to 15 miles, result in the third source mechanism. These movements occur on the crust of the North America tectonic plate when built-up stresses near the surface are released. There are several crustal faults in the project site region, including the Rattlesnake-Wallula Trend, Columbia Hills Anticline, and Horse Heaven Hills NW Fault (Geomatrix 1995, 1996). These faults are generally considered to be inactive or have a low probability of activity. The most notable earthquake event in the past century occurred on July 15, 1936 near Umapine, Oregon, approximately 35 miles to the east-southeast. The Umapine quake has been set at magnitude 5.7 or 6.4 on the Richter Scale by different resources, and was felt through large portions of Washington, Oregon, and Idaho, and caused ground cracking, small areas of soil liquefaction, structural damage, and isolated building collapses near Walla Walla, Washington and Milton-Freewater, Oregon. Damage was also reported in Waitsburg (approximately 50 east of the project site), and the quake was felt in Kennewick (estimated Modified Mercalli (MM) Intensity of III) but no damage was reported. Within the past 10 years there have been a total of 28 earthquakes within a 100 kilometer radius from the site. The largest of these episodes had a magnitude of 3.7 and a hypocenter of 20 kilometers below the surface. It occurred in 2008 and the epicenter was 27 kilometers away from the site at a location of N 46.17 W -119.55. Of the 28 total earthquakes in the past 10 years, 21 had a focus of 10 kilometers or less, 6 were between 25 kilometers and 11 kilometers, and 1 was greater than 25 kilometers deep (a focus of 36 kilometers below the surface). All 28 events have an average magnitude of 2.9 on the Richter scale. Regional Faulting: There are three main fault structures in the project site region. These three consists of the Rattlesnake Hills fault/fold structure, the Horse Heaven Hills structure, and the Wallula Fault system. These three structures are included in many of the regional lineaments in the area including the Olympic Wallowa Lineament (OWL), the Cle Elum-Wallula deformed zone (CLEW), and the Rattlesnake-Wallula trend (RAW). EXHIBIT 12 Page 18 of 144 ---PAGE BREAK--- Proposed ‘Sunrise Ridge’ Residential Dev. GNN Project No.: 216-672 S. Olympia Street, Kennewick, Washington February 25, 2016 17 The Horse Heaven Hills structure is one of the longest fold and fault systems in south-central Washington, and is part of the Yakima Fold Belt. The structures are primarily north-verging anticlines possibly underlain by south-dipping thrust and reverse faults. Tightening or growth of other Yakima Fold Belt structures, and possibly the Horse Heaven Structures, has been hypothesized; however poor exposure of Quaternary deposits and lack of detailed mapping prevent determination of this. No definitive evidence has been documented to show Quaternary movement in the Horse Heaven Hills. The Rattlesnake Hills fault/fold structures are also anticlinal segments cut and underlain by south- to southwest-dipping thrust or reverse faults in rocks of the Miocene CRBG. These anticlinal segments characterize the southeastern part of the Rattlesnake Hills uplift and are an echelon double-plunging anticline. The faults of the Rattlesnake Hills structures are covered by loess, landslide, and glacial outburst flood deposits of Quaternary age for much of their length. Based on published geologic maps, the concealed/buried alignment of the Rattlesnake Hills structure crosses beneath the south-central portion of the site. Approximate Fault Alignment Map (Figure 4, Appendix I) shows the approximate alignment of the buried/concealed fault zone, as mapped by Washington State Department of Resources – Washington Interactive Geologic Map. As with the Horse Heaven Structures, movement and tightening has been inferred, but no conclusive evidence has been presented to prove this, and no definitive evidence has been documented to show Quaternary displacement; the Rattlesnake Hills structure is therefore identified as a Class B fault. The Wallula Fault System is a prominent northwest-striking fault zone that extends from near Milton-Freewater, OR to near Kennewick, WA. The northwest projection of the Wallula fault is generally mapped to line-up with the southeast projection of the Rattlesnake Hills fault. Unlike the two previously described structures, the Wallula Fault System is mostly mapped as linear, steeply dipping strike-slip, normal, or reverse faults in Quaternary surficial deposits and rocks of the Columbia River Basalt Group. The mapped fault pattern, and other evidence, supports a right- lateral strike-slip sense of movement on the Wallula Fault. Although poorly studied, some evidence suggests up to four surface-faulting events within the past 10,000 years along a portion of the Wallula Fault System in northeastern Oregon. Slip rate on all three faults is estimated to be less than 0.2 millimeters per year. EXHIBIT 12 Page 19 of 144 ---PAGE BREAK--- Proposed ‘Sunrise Ridge’ Residential Dev. GNN Project No.: 216-672 S. Olympia Street, Kennewick, Washington February 25, 2016 18 Secondary Seismic Hazards Secondary seismic hazards related to ground shaking include soil liquefaction, ground subsidence, tsunamis, and seiches. The site is far inland, so the hazard from tsunamis is non-existent. The potential hazards from seiches generated in the adjacent KID Canal are also considered nil due to grade differential and the noted low magnitudes of potential seismic shaking. Soil Liquefaction Liquefaction is the loss of soil strength from sudden shock (usually earthquake shaking), causing the soil to become a fluid mass. In general, for the effects of liquefaction to be manifested at the surface, groundwater levels must be within 50 feet of the ground surface and the soils within the saturated zone must also be susceptible to liquefaction. A detailed liquefaction analysis was beyond the scope of this report. Based on the published Liquefaction Susceptibility Map of Benton County, Washington (dated September 2004) prepared by Washington State Department of Natural Resources, the site is primarily mapped in the upper portion as bedrock (non-liquefiable), with the lower portion mapped with a designation of ‘Very Low’potential for liquefaction. Slope Stability Based on site-specific topography, current site elevations within the project boundary range from approximately 845 in the southwestern portion near S. Olympia Street, to 670 feet MSL in the northern portion near the KID canal. Native slope gradients at the site generally range from approximately 10% to 33% in the northern and western portions, and approximately 10% to 29% across the southeastern and southwestern slopes. Existing fill slopes at the site were noted to be as steep as 50% (2H:1V). A field reconnaissance of the subject property was performed to observe site conditions and correlate the information gathered from our preliminary research. During our reconnaissance we looked for common geomorphic features of landslides as well as indications of possible signs demonstrating recent activity and instability of slide masses. No apparent indications of existing failure or significant slope instability were observed. EXHIBIT 12 Page 20 of 144 ---PAGE BREAK--- Proposed ‘Sunrise Ridge’ Residential Dev. GNN Project No.: 216-672 S. Olympia Street, Kennewick, Washington February 25, 2016 19 Flooding and Erosion Based on a review of the published FEMA flood map (Community-Panel Number [PHONE REDACTED] B) for the site vicinity (Appendix VII), the subject property is not mapped within designated flood plains. The subject property is situated in an area where sheet flow and erosion may occur and the mapped pre-existing intermittent stream drainage crossing the site has been altered by historic site grading and filling. The near-surface site soils and surface conditions are known to exhibit a moderate to severe risk for erosion. Site observations revealed some areas of minor basins (low areas) with moist surface conditions, and apparent soil erosion. Apparent rill and gully erosion was noted along fill slopes in the eastern portion of the site and along the existing access road. Erosion susceptibility from water is based on several factors, including the intensity of rainfall and runoff, soil erodibility, length and steepness of slopes, and surface condition. The erodibility factor of the soils is a measure of the soils resistance to erosion based on its physical characteristics. Typically very fine sand, silt and clay soils are generally susceptible to erosion. Based on site specific field exploration, observations, and laboratory testing, the surficial soil exposed at the project site consists primarily of silt with fine sand (sandy loam). Soil erodibility is only one of several factors affecting the erosion susceptibility. Soil erosion by water also increases with the length and steepness of the site slopes due to the increased velocity of runoff and resulting greater degree of scour and sediment transport. Appropriate erosion and sediment control plan(s) and a drainage plan shall be prepared by the project civil engineer with the final construction drawings. The need for and design of flood control devices and erosion protection measures is within the purview of the design Civil Engineer. In general, erosion should be mitigated with best management practices (BMPs) consisting of proper drainage design including collecting and disposal (conveyance) of water to approved points of discharge in a non-erosive manner. Appropriate project design, construction, and maintenance will be necessary to mitigate the site erosion hazards. EXHIBIT 12 Page 21 of 144 ---PAGE BREAK--- Proposed ‘Sunrise Ridge’ Residential Dev. GNN Project No.: 216-672 S. Olympia Street, Kennewick, Washington February 25, 2016 20 SLOPE STABILITY ANALYSIS Slope stability analyses were conducted on selected existing slopes to evaluate their present state of stability, as well as proposed reconfigured slopes for the proposed project. The analyses were conducted using a generalized geologic cross section model developed from the existing and proposed site topography, and data obtained from our subsurface exploration. Slope stability of the existing site slopes was completed on five slope section models as shown on Figures 8A and 8B (Appendix with associated section cut lines shown on Site Exploration Plan (Figure 7, Appendix Based on the preliminary grading plan, stability analysis for the proposed 2H:1V slope re-configurations was performed on the tallest cut slope, 22 feet tall cut slope in the southeastern portion of the site, and the tallest proposed fill slope, 38 feet tall in the northern portion of the site. Outputs of our slope stability analyses are attached in Appendix V. The slope stability analyses were conducted by a two-dimensional limit equilibrium stability analysis of selected trial failure surfaces using the computer program SLIDE. Potential circular-arc failure surfaces were evaluated using the Spencer method. The computer program searched for critical potential failure surfaces with low computed factors of safety. The computed factor of safety (FS) against slope failure is simply the ratio of total resisting forces or moments (strength of the slope) to the total driving forces or moments for planar or circular failure surfaces respectively. A slope with a factor of safety of 1.0 is in equilibrium, indicating that the disturbing forces driving the slope down are equal to its strength to resist failure. Simply put slope-failure result when the strength of the slope is overcome by gravity. Although earthquakes are generally not a significant concern in the Tri-Cities region, and anticipated seismic accelerations are expected to be relatively low, the stability of the slopes have been analyzed under both static and seismic conditions. Our analysis used the pseudostatic method which modifies the limit equilibrium method by incorporating a horizontal static seismic force to simulate the potential inertial forces generated from earthquake ground accelerations. For slope stability analyses under seismic loading, a pseudostatic seismic coefficient, kh (horizontal component), expressed in terms of acceleration (units of is typically estimated as a percentage of the horizontal peak ground acceleration (PGA). PGA for this site was calculated with a 950-year return interval (RI) using the USGS PSH Deaggregation tool for a 10% probability of exceedance EXHIBIT 12 Page 22 of 144 ---PAGE BREAK--- Proposed ‘Sunrise Ridge’ Residential Dev. GNN Project No.: 216-672 S. Olympia Street, Kennewick, Washington February 25, 2016 21 in 100 years. For our analyses, we have selected a value of kh = 0.06g, approximately half of the design PGA of 0.101g. The selection of unit weight and shear strength parameters for the various earth materials were based on judgment and data obtained during our field investigation, laboratory testing, review of previous studies, research and previous experience with similar materials in similar geotechnical and geologic settings. Engineering and geologic judgment must be applied to the results of shear tests in order to consider lateral and vertical variations in the subsurface conditions, such as degree of cementation, fracturing, planes of weakness, and gradational characteristics. The following geotechnical strength parameters were used in our stability calculations: Table 3: Estimated Strength Parameters Material Shear Strength Parameters Unit Weight Friction Angle: I Cohesion: c (psf) (pcf) Native: Silt with Sand (low strength) 29 0 90 Native: Silt with Sand (relatively high strength) 34 0 110 Native: Silty Gravel 38 0 125 Fill: Loose (side-cast) 28 0 110 Fill: Undocumented trash/debris) 20 0 115 Engineered Fill (re-compacted onsite silt) 33 0 118 Engineered Fill (imported granular material) 35 0 120 Our slope stability analyses generally indicate two primary modes of failure: deep-seeded global failure through the slope, and shallow surficial failure through the near-surface (loose) soils. The factors of safety against slope failure, using the shear strength data as described above, were computed for existing and proposed slope configurations as summarized below: EXHIBIT 12 Page 23 of 144 ---PAGE BREAK--- Proposed ‘Sunrise Ridge’ Residential Dev. GNN Project No.: 216-672 S. Olympia Street, Kennewick, Washington February 25, 2016 22 Table 4: Calculated Factors of Safety Slope Section Slope Condition Static Factor of Safety Seismic Factor of Safety Local Global A-A’ Existing 1.9 2.1 1.7 B-B’ 1.3 2.4 1.9 C-C’ Upper 1.5 1.4 1.6 C-C’ Lower 1.0 1.3 D-D’ 3.3 3.5 2.5 E-E’ 1.9 2.0 1.7 22’ feet tall 2H:1V cut slope Proposed 1.1 1.5 1.3 38’ feet tall 2H:1V fill slope 1.3 1.4 1.2 GN Northern recommends that any reconfigured slopes should meet or be designed and constructed to meet a minimum factor of safety of 1.5 for the static condition and 1.1 under seismic loading. Our analysis indicates that existing native (undisturbed) site slopes, along with the existing engineered fill slope (shown in Section meet or exceed these minimums. However, the existing fill slope present along the eastern-most boundary of the project site does not meet the minimum required safety factor. The noted shallow failures through the near-surface soils represent relatively insignificant displacement of the soft surficial veneer of residual soils that should be readily mitigated with appropriate erosion control measures (BMPs). Our stability analyses of the proposed (re-graded) slopes indicates that 2H:1V cut slopes as tall as 22 feet in net height, into the native existing hillsides, will meet/exceed the required minimum safety factors. Our analysis indicates that the proposed 2H:1V, 38 feet tall fill slope constructed using the onsite native silty material placed as compacted engineered fill, does not meet the minimum required factors of safety. Based on additional analysis, we recommend that fill slopes constructed with a 2H:1V slope gradient shall be limited to 15-feet in net (total) height. For fill slopes constructed at 2H:1V slope gradient, using imported granular material (as specified in the Engineered Fill section), we recommend a net slope height of no greater than 25-feet. EXHIBIT 12 Page 24 of 144 ---PAGE BREAK--- Proposed ‘Sunrise Ridge’ Residential Dev. GNN Project No.: 216-672 S. Olympia Street, Kennewick, Washington February 25, 2016 23 We recommend that all proposed cut and fill slopes at project site shall be constructed in accordance with the recommendations (Graded Slope Construction section) of this report. Optional steeper and/or taller slopes can be considered by the developer, however they will require an engineered reinforcement or reduced gradient, respectively, to increase safety factors and reduce the potential for slope failure (see Optional Reinforced Engineered Slopes section below). EXHIBIT 12 Page 25 of 144 ---PAGE BREAK--- Proposed ‘Sunrise Ridge’ Residential Dev. GNN Project No.: 216-672 S. Olympia Street, Kennewick, Washington February 25, 2016 24 FINDINGS AND CONCLUSIONS The following is a summary of our findings, conclusions and professional opinions based on the data obtained from a review of selected technical literature and the site evaluation: General: ¾ Based on our current understanding of the proposed development and subsurface conditions encountered, from a geologic perspective, it is our professional opinion that the site is suitable for the proposed development, provided the recommendations in this report and any subsequent site specific/design-level geotechnical evaluations are followed in the design and construction of this project. ¾ This report does not constitute a geotechnical engineering report for development of the proposed residential subdivision at the project site. Additional lot- and structure-specific geotechnical evaluation(s) and recommendations will be required for the proposed residential subdivision infrastructure improvements and future residential structures. ¾ The recommendations in this report are indented to address any noted geologic hazards relative to development of the proposed subdivision infrastructure. Additional geotechnical investigations and recommendations will be necessary to address site constraints of future additional structures and improvements. Geologic/Geotechnical Constraints and Mitigation: ¾ The primary geologic hazards and site constraints for the proposed project include surface erosion and the potential for slope failures. Engineered design and careful construction as recommended within this report can mitigate these geologic constraints and increase safety to allow development of potentially geologically hazardous areas. ¾ Although the alignment of the noted buried and concealed Rattlesnake Hills fault/fold structure crosses beneath the project site, it is not considered “active” with Holocene period displacement. We do not believe the Rattlesnake Hills structure represents or poses a significant geologic hazard risk to the proposed development of the site. EXHIBIT 12 Page 26 of 144 ---PAGE BREAK--- Proposed ‘Sunrise Ridge’ Residential Dev. GNN Project No.: 216-672 S. Olympia Street, Kennewick, Washington February 25, 2016 25 ¾ Other common geologic hazards, including fault rupture, liquefaction, and seismic shaking are considered low or negligible on this site. ¾ Site soils are susceptible to wind and water erosion. Preventative measures to control runoff and reduce erosion should be incorporated into site grading plans. ¾ Large areas of the subject site have historically been subject to placement of significant volumes of imported fill materials. Based on the findings of our subsurface exploration of the site, some fill materials were observed to include miscellaneous trash and construction debris including concrete rubble, asphalt, wood, and metal. While the upper fill layer in the central portion of the site was properly placed in 2014 as engineered fill with associated testing and inspection, the deeper underlying fill materials consist of undocumented and uncontrolled fill. ¾ Development on sloping ground poses an inherent risk related to global and local stability of site slopes. The proposed project site development will require careful design and construction including slope stabilization and drainage/erosion control measures to mitigate the observed geotechnical and geologic site constraints. ¾ As depicted on the current preliminary grading plans, individual residential lots and portions along the width of the proposed roadways will be constructed with partial cut and partial fill grading. ¾ Site development may require the use of earth retaining structures as well as extensive grading to construct safe cut and fill slopes as proposed. ¾ Our analysis indicates that existing native (undisturbed) site slopes, along with the existing engineered fill slope (shown in Section meet or exceed these minimums. However, the existing fill slope present along the eastern-most boundary of the project site does not meet the minimum required safety factor. ¾ Our stability analyses of the proposed (re-graded) slopes indicates that 2H:1V cut slopes as tall as 22 feet in net height, into the native existing hillsides, will meet/exceed the required minimum safety factors. Our analysis indicates that the proposed 2H:1V, 38 feet tall fill slope EXHIBIT 12 Page 27 of 144 ---PAGE BREAK--- Proposed ‘Sunrise Ridge’ Residential Dev. GNN Project No.: 216-672 S. Olympia Street, Kennewick, Washington February 25, 2016 26 constructed using the onsite native silty material placed as compacted engineered fill, does not meet the minimum required factors of safety. ¾ We recommend that fill slopes constructed with a 2H:1V slope gradient shall be limited to 15- feet in net (total) height. For fill slopes constructed at 2H:1V slope gradient, using imported granular material (as specified in the Engineered Fill section), we recommend a net slope height of greater than 25-feet. ¾ The noted shallow failures through the near-surface soils represent relatively insignificant displacement of the soft surficial veneer of residual soils that should be readily mitigated with appropriate erosion control measures (BMPs). ¾ We recommend that GNN be provided an opportunity to complete subsequent slope stability analyses on a structure- and lot-specific design basis. ¾ Remedial site grading will be necessary to appropriately mitigate the noted existing poor fill soil conditions and to develop appropriate cut/fill slopes and provide uniform competent support for future residential home-sites and subdivision infrastructure improvements. ¾ Adherence to the grading and structural recommendations in this report should reduce the potential hazard of slope failure, erosion and settlement problems. ¾ Optional steeper and/or taller slopes can be considered by the developer, however they will require an engineered reinforcement or reduced gradient, respectively, to increase safety factors and reduce the potential for slope failure. ¾ The upper soils were found to be relatively loose to medium dense and are unsuitable in their present condition to support structures, fill, and hardscape. The soils within the areas of proposed improvements will require moisture conditioning, over-excavation, and recompaction. ¾ Onsite soils can be readily cut by normal grading equipment. EXHIBIT 12 Page 28 of 144 ---PAGE BREAK--- Proposed ‘Sunrise Ridge’ Residential Dev. GNN Project No.: 216-672 S. Olympia Street, Kennewick, Washington February 25, 2016 27 ¾ Due to the variability of the onsite materials including significant areas of existing fill, in our opinion the lowest infiltration rate (12 inches/hour), with an appropriate factor of safety, may be used for the native silty soils. For final design of the stormwater infiltration facilities, we recommend performing location- and depth-specific infiltration testing, following completion of site grading, to fully analyze the infiltration characteristics of the onsite material. ¾ We recommend that lot-specific geotechnical evaluation should establish appropriate slope set- backs for future structures and development. ¾ In our professional opinion, the proposed residential development at the site will not pose a threat to the health or safety of the citizens, or increase hazards to surrounding properties, provided the recommendations in this report and any subsequent site specific/design-level geotechnical evaluations are followed in the design and construction of this project. EXHIBIT 12 Page 29 of 144 ---PAGE BREAK--- Proposed ‘Sunrise Ridge’ Residential Dev. GNN Project No.: 216-672 S. Olympia Street, Kennewick, Washington February 25, 2016 28 RECOMMENDATIONS The recommendations in this report are indented to address any noted geologic hazards, including slope stability and erosion concerns relative to development of the proposed residential subdivision infrastructure. Additional geotechnical investigations and recommendations will be necessary to address site constraints of future additional structures and improvements. Furthermore, these recommendations are predicated upon appropriate monitoring and testing of the site grading activities by a representative of our Geotechnical-Engineer-of-Record (GER). Site Development – Grading Site grading shall incorporate the requirements of IBC 2012 Appendix J and/or City of Kennewick. The project GER or a representative of the GER should observe site clearing, grading, and the bottoms of excavations before placing fills. Local variations in soil conditions may warrant increasing the depth of over-excavation and recompaction. Seasonal weather conditions may adversely affect grading operations. To improve compaction efforts and prevent potential pumping and unstable ground conditions, we suggest performing site grading during dryer periods of the year. Soil conditions shall be evaluated by in-place density testing, visual evaluation, probing, and proof-rolling of the imported fill and re-compacted on-site soil as it is prepared to check for compliance with recommendations of this report. A moisture-density curve shall be established in accordance with the ASTM D1557 method for all onsite soils and imported fill materials used as structural fill. Clearing and Grubbing: At the start of site grading, areas of proposed improvements should be cleared of existing vegetation, large roots, non-engineered fill, construction debris, trash, and abandoned underground utilities. The surface should be stripped of organic growth and removed from the construction area. Areas disturbed during clearing should be properly backfilled and compacted as described below. Removal of existing vegetation should be carefully controlled and limited to only those areas of proposed improvements and associated grading. Site vegetation and surface conditions should be maintained in their native condition to the greatest extent possible during construction. Areas EXHIBIT 12 Page 30 of 144 ---PAGE BREAK--- Proposed ‘Sunrise Ridge’ Residential Dev. GNN Project No.: 216-672 S. Olympia Street, Kennewick, Washington February 25, 2016 29 disturbed during grading and construction should employ appropriate BMPs and be immediately protected and/or re-vegetated to control runoff and erosion. Engineered Fill: The native soil may be suitable for use as engineered fill and utility trench backfill, provided it is free of significant organic or deleterious matter. The native soil should be placed in maximum 8-inch lifts (loose) and compacted to at least 95% relative compaction (ASTM D1557) near its optimum moisture content. Compaction should be verified by testing. Rocks larger than 6 inches in greatest dimension should be removed from fill or backfill material. Imported fill soils should be non-expansive, granular soils meeting the USCS classifications of SM, SP-SM, or SW-SM with a maximum rock size of 3 inches, minimum 80% passing the No. 4 sieve, and 5 to 35% passing the No. 200 sieve. The GER should evaluate the import fill soils before hauling to the site. However, because of the potential variations within the borrow source, import soil will not be prequalified by GNN. The imported fill should be placed in lifts no greater than 8 inches in loose thickness and compacted to at least 95% of the maximum dry density (ASTM D1557) near optimum moisture content. Graded Slope Construction Development on sloping ground poses an inherent risk related to global and local stability of site slopes. In order to mitigate the potential hazards of erosion and slope instability, site development will require careful design and construction including slope stabilization and drainage/erosion control measures to mitigate the observed geotechnical and geologic site constraints. Proposed development of the site will require areas of significant slope grading in addition to the possible use of earth retaining structures. Our stability analyses of the proposed (re-graded) slopes indicates that 2H:1V cut slopes as tall as 22 feet in net height, into the native existing hillsides, will meet/exceed the required minimum safety factors. Our analysis indicates that the proposed 2H:1V, 38 feet tall fill slope constructed using the onsite native silty material placed as compacted engineered fill, does not meet the minimum required factors of safety. All reconfigured slopes should be overfilled and trimmed back to competent material. A representative of the GER should observe all construction cuts to inspect for adverse geologic EXHIBIT 12 Page 31 of 144 ---PAGE BREAK--- Proposed ‘Sunrise Ridge’ Residential Dev. GNN Project No.: 216-672 S. Olympia Street, Kennewick, Washington February 25, 2016 30 conditions and make appropriate recommendations based on the exposed conditions. Grading details for proper slope construction are shown below: EXHIBIT 12 Page 32 of 144 ---PAGE BREAK--- Proposed ‘Sunrise Ridge’ Residential Dev. GNN Project No.: 216-672 S. Olympia Street, Kennewick, Washington February 25, 2016 31 BMPs to control erosion on all graded slopes will be required. Landscaping should take into consideration the engineering characteristics of the slopes, especially with regards to the surficial stability of the slopes. Fill Slopes (2H:1V Maximum Gradient) We recommend that fill slopes constructed with a 2H:1V (max.) slope gradient shall be limited to 15-feet in net (total) height. For fill slopes constructed at 2H:1V (max.) slope gradient, using imported granular material (as specified in the Engineered Fill section), we recommend a net slope height of greater than 25-feet. Fill slopes should be overfilled and trimmed back to uniformly compacted material. The final slope surface should be track-walked or grid rolled to improve the slope's resistance to erosion. Where fill slopes or stabilization fill slopes are to be constructed on natural slopes steeper than 5V:1H, the fill should be keyed and benched into firm natural soil. Keyways for all slopes, greater than 5 feet in height, should be cut into firm natural soil. This helps ensure a good bond between the existing native soil and new fill, and to eliminate a plane of weakness at the interface. Benching dimensions into existing native slopes shall be a minimum 5 feet horizontal and maximum 4 feet vertical from the lowest adjacent soil grade. Before engineered fill is placed, the key should be observed by a representative of the GER, to observe compliance with the above recommendations. It is recommended that the GER, or their representatives, be present during the fill construction to observe compliance with the above recommendations. Compacted fill slopes shall be overbuilt and cut back to grade, exposing the firm, compacted fill inner core. The actual amount of overbuilding should vary as field conditions dictate. The degree of overbuilding should be increased until the desired compacted slope surface condition is achieved. Care should be taken by the contractor to provide thorough mechanical compaction to the outer edge of the overbuilt slope surface. Fill placement should proceed in thin lifts 10 inch loose thickness, depending upon compaction equipment). Each lift should be moisture- conditioned and thoroughly compacted. The desired moisture condition should be maintained during the period between successive lifts, and each lift should be tested to ascertain that desired compaction is being achieved. EXHIBIT 12 Page 33 of 144 ---PAGE BREAK--- Proposed ‘Sunrise Ridge’ Residential Dev. GNN Project No.: 216-672 S. Olympia Street, Kennewick, Washington February 25, 2016 32 At intervals not exceeding 4 feet in vertical slope height or the capability of available equipment, whichever is less, fill slopes should be thoroughly back-rolled utilizing conventional equipment. Care should be taken to maintain the desired moisture conditions as needed prior to back-rolling. Upon achieving final grade, the slopes should again be moisture conditioned and thoroughly back-rolled. The use of a side boom roller may be necessary as well as vibratory methods. Without delay, the slopes should then be grid-rolled to achieve a relatively smooth surface and uniformly compact condition. Slope construction procedures shall be monitored, and moisture and density tests shall be taken at regular intervals. Cut Slopes (2H:1H Maximum Gradient) Based on our slope stability analysis of the proposed 22-foot high 2H:1V cut slope (max), remedial grading of the proposed slope face will be required. We recommend reconstruction of the slope face by keying and benching into native soils, along with replacement with engineered fill. A key shall be constructed at the toe of the proposed cut slope, 24-inches deep, with horizontal dimensions of 10 feet of H/2 (where H is the finished height of the slope). Benching dimensions into native cut slopes shall be a minimum 5 feet horizontal and maximum 4 feet vertical from the lowest adjacent soil grade. The exposed native surface of the overcut bench should be scarified, moisture conditioned, and recompacted to a dense and non-yielding surface prior to replacement with engineered fill. The reconstructed cut slope faces shall be overbuilt and cut back to grade, exposing the firm and compacted surface. The GER, or their representatives, should monitor cut slopes during construction, to check for adverse geologic features exposed within the cut face. A representative of the GER, should monitor cut slopes during construction, to check for adverse geologic features exposed within the cut face. Although not anticipate, proposed slopes may require finished at a shallower gradient or reconstruction as buttressed slopes if adverse geologic conditions and/or unsuitable trash and debris are exposed during construction. Optional Engineered Reinforced Slopes (Steeper Than 2H:1V) If considered by the developer, slopes constructed at gradients steeper than 2H:1V will require an engineered reinforcement design to increase the factor of safety against slope failure to acceptable minimums. Several methods of engineered slope reinforcement are available. One of the more cost effective methods for slope reinforcement will consist of the inclusion of multiple layers of EXHIBIT 12 Page 34 of 144 ---PAGE BREAK--- Proposed ‘Sunrise Ridge’ Residential Dev. GNN Project No.: 216-672 S. Olympia Street, Kennewick, Washington February 25, 2016 33 reinforcements (geogrids) placed horizontally during grading operations to construct the proposed slopes. The commonly used term of mechanically stabilized earth (MSE) best describe this method of soil reinforcement, or reinforced soils slopes (RSS) for use in engineered strengthened slopes. Design requirements for MSE slope structures should be developed in accordance with the Federal Highway Administration’s “Mechanically Stabilized Earth Walls and Reinforced Soil Slopes Design and Construction Guidelines” (FHWA NHI-00-043, 2001). In addition to slope angle and soil strength parameters, the stability of the slopes is also controlled in part by the overall slope height and surcharge loads. Surface erosion control and internal drainage are also important integral parts of the final design and construction of the reinforced soils slopes. The engineered reinforcement should be designed to result in a stable slope with a minimum computed factor of safety of 1.5 for the static condition. Because of the numerous variables controlling the effectiveness of the engineered reinforcement for optional steeper slopes, a specific reinforced slope design, including geogrids specification, spacing and embedment depths should be prepared for all proposed slopes with gradients steeper than 2H:1V. Careful site layout, planning and construction sequencing will be necessary to ensure that reinforced slopes are not weekend by subsequent construction of future improvements. Slope Maintenance and Erosion Protection Future proposed building sites will require appropriate setbacks from adjacent ascending or descending slopes in accordance with IBC Section 1808.7. Proper slope protection and maintenance will help minimize slope erosion and improve the stability of the project slopes. The project soils are prone to erosion and will require appropriate BMP protection and maintenance. Positive drainage should be provided at the tops of all slopes to divert runoff away from the face. Swales constructed in native soils should be lined with suitable no-erosive material. Erosion protection should be provided, especially where concentrated runoff is anticipated. A qualified Landscape Architect should provide recommendations for slope planting. As the exposed site soils are susceptible to erosion, it is required that erosion control measures, such as planting, erosion control blankets or fabrics, sprayed tackifiers, or some combination of these, be utilized on all slopes within the project. Landscaping should take into consideration the engineering characteristics of the slopes, especially with regards to the surficial stability. EXHIBIT 12 Page 35 of 144 ---PAGE BREAK--- Proposed ‘Sunrise Ridge’ Residential Dev. GNN Project No.: 216-672 S. Olympia Street, Kennewick, Washington February 25, 2016 34 The need for and design of flood control and erosion protection measures is within the purview of the design civil engineer. In general, erosion should be mitigated with best management practices (BMPs) consisting of proper drainage design including collecting and disposal (conveyance) of water to approved points of discharge in a non-erosive manner. Appropriate project design, construction, and maintenance will be necessary to mitigate the site erosion concerns. EXHIBIT 12 Page 36 of 144 ---PAGE BREAK--- Proposed ‘Sunrise Ridge’ Residential Dev. GNN Project No.: 216-672 S. Olympia Street, Kennewick, Washington February 25, 2016 35 REFERENCES Benton County Parcel Information Service, Franklin County Website - Parcel Information website, http://bentonpropertymax.governmaxa.com City of Kennewick, Kennewick Municipal Code (KMC), Title 18.58 - Critical Areas - General Provisions, published March 10, 2014 City of Kennewick, Kennewick Municipal Code (KMC), Title 18.62 - Critical Areas - Geologically Hazardous Areas, published March 10, 2014 Federal Emergency Management Agency (FEMA), National Flood Insurance Program, Flood Insurance Map (FIRM), Benton County, Washington, Community-Panel Number [PHONE REDACTED] B, effective date: July 19, 1982 GN Northern Inc., Geologic Assessment and Critical Areas Report, Olympia Street Project - Assessor’s Parcel No. 124893012820003, Kennewick, WA, Project No. 213-422, dated October 30, 2013 GN Northern Inc., Olympia Street Parcel 124893012820003, Kennewick, Washington, Grading Plan, Drawing No. 1/1, Rev. 1, Job No. 213-422, dated June 24, 2014 HDR, City of Kennewick - Critical Areas Map - Geologically Hazardous Areas, 2007 Historic Plus Research Service, Aerial Photo Search, ID: H1979.1000, dated 10/28/2013 JF Engineering, preliminary grading plans, Sunrise Ridge Subdivision, JF Eng. Job # 0032.00, sheets C300/C301, dated February 18 & 19, 2016 Rocscience, Inc., SLIDE, version 7.0, slope stability analysis computer program United States Geological Survey, 2008 PSHA Interactive Deaggregation on-line tool, http://geohazards.usgs.gov/deaggint/2008/ United States Department of the Interior Geological Survey (USGS), Kennewick Quadrangle - Washington - 7.5 Minute Series Topographic map, 1964 United States Department of the Interior Geological Survey (USGS), Kennewick Quadrangle - Washington - 7.5 Minute Series Topographic map, 1992 Washington State Department of Natural Resources (DNR), Washington Division of Geology and Earth Resources, on-line mapping tool, Washington State Department of Natural Resources (DNR), Liquefaction Susceptibility Map of Benton County, Washington, September 2004 EXHIBIT 12 Page 37 of 144 ---PAGE BREAK--- Proposed ‘Sunrise Ridge’ Residential Dev. GNN Project No.: 216-672 S. Olympia Street, Kennewick, Washington February 25, 2016 36 ADITIONAL SERVICES GNN recommends that the Client should maintain an adequate program of geotechnical consultation, construction monitoring, and soils testing during the final design and construction phases to monitor compliance with GNN’s geotechnical recommendations. Maintaining GNN as the geotechnical consultant from beginning to end of the project will provide continuity of services. If GN Northern, Inc. is not retained by the owner/developer and/or the contractor to provide the recommended geotechnical inspections/observations and testing services, the geotechnical engineering firm or testing/inspection firm providing tests and observations shall assume the role and responsibilities of Geotechnical Engineer-of-Record. GNN can provide construction monitoring and testing as additional services. The costs of these services are not included in our present fee arrangement, but can be obtained from our office. The recommended construction monitoring and testing includes, but is not necessarily limited to, the following: ¾ Consultation during the design stages of the project. ¾ Review of the grading and drainage plans to monitor compliance and proper implementation of the recommendations in GNN’s Report. ¾ Observation and quality control testing during site preparation, grading, and placement of engineered fill as required by the local building ordinances. ¾ Geotechnical engineering consultation as needed during construction EXHIBIT 12 Page 38 of 144 ---PAGE BREAK--- Proposed ‘Sunrise Ridge’ Residential Dev. GNN Project No.: 216-672 S. Olympia Street, Kennewick, Washington February 25, 2016 37 LIMITATIONS OF THE GEOHAZARDS ASSESSMENT & CRITICAL AREAS REPORT This GEOHAZARDS ASSESSMENT & CRITICAL AREAS REPORT (“Report”) was prepared for the exclusive use of the Client. GN Northern, Inc.’s (GNN) findings, conclusions and recommendations in this Report are based on selected points of field exploration, laboratory testing, and GNN’s understanding of the proposed project at the time the Report is prepared. Furthermore, GNN’s findings and recommendations are based on the assumption that soil, rock and/or groundwater conditions do not vary significantly from those found at specific exploratory locations at the project site. Variations in soil, bedrock and/or groundwater conditions could exist between and beyond the exploration points. The nature and extent of these variations may not become evident until during or after construction. Variations in soil, bedrock and groundwater may require additional studies, consultation, and revisions to GNN’s recommendations in the Report. In many cases the scope of geotechnical exploration and the test locations are selected by others without consultation from the geotechnical engineer/consultant. GNN assumes no responsibility and, by preparing this Report, does not impliedly or expressly validate the scope of exploration and the test locations selected by others. This Report’s findings are valid as of the issued date of this Report. However, changes in conditions of the subject property or adjoining properties can occur due to passage of time, natural processes, or works of man. In addition, applicable building standards/codes may change over time. Accordingly, findings, conclusions, and recommendations of this Report may be invalidated, wholly or partially, by changes outside of GNN’s control. Therefore, this Report is subject to review and shall not be relied upon after a period of one year from the issued date of the Report. In the event that any changes in the nature, design, or location of structures are planned, the findings, conclusions and recommendations contained in this Report shall not be considered valid unless the changes are reviewed by GNN and the findings, conclusions, and recommendations of this Report are modified or verified in writing. This Report is issued with the understanding that the owner or the owner’s representative has the responsibility to bring the findings, conclusions, and recommendations contained herein to the EXHIBIT 12 Page 39 of 144 ---PAGE BREAK--- Proposed ‘Sunrise Ridge’ Residential Dev. GNN Project No.: 216-672 S. Olympia Street, Kennewick, Washington February 25, 2016 38 attention of the architect and design professional(s) for the project so that they are incorporated into the plans and construction specifications, and any follow-up addendum for the project. The owner or the owner’s representative also has the responsibility to verify that the general contractor and all subcontractors follow such recommendations during construction. It is further understood that the owner or the owner’s representative is responsible for submittal of this Report to the appropriate governing agencies. The foregoing notwithstanding, no party other than the Client shall have any right to rely on this Report and GNN shall have no liability to any third party who claims injury due to reliance upon this Report, which is prepared exclusively for Client’s use and reliance. GNN has provided geotechnical services in accordance with generally accepted geotechnical engineering practices in this locality at this time. GNN expressly disclaims all warranties and guarantees, express or implied. Client shall provide GNN an opportunity for to review the final design and specifications so that earthwork, drainage and foundation recommendations may be properly interpreted and implemented in the design and specifications. If GNN is not accorded the review opportunity, GNN shall have no responsibility for misinterpretation of GNN’s recommendations. Although GNN can provide environmental assessment and investigation services for an additional cost, the current scope of GNN’s services does not include an environmental assessment or an investigation for the presence or absence of wetlands, hazardous or toxic materials in the soil, surface water, groundwater, or air on, below, or adjacent to the subject property. EXHIBIT 12 Page 40 of 144 ---PAGE BREAK--- APPENDICES EXHIBIT 12 Page 41 of 144 ---PAGE BREAK--- APPENDIX I Figures, Maps, & Fence Diagrams EXHIBIT 12 Page 42 of 144 ---PAGE BREAK--- EXHIBIT 12 Page 43 of 144 ---PAGE BREAK--- EXHIBIT 12 Page 44 of 144 ---PAGE BREAK--- EXHIBIT 12 Page 45 of 144 ---PAGE BREAK--- EXHIBIT 12 Page 46 of 144 ---PAGE BREAK--- EXHIBIT 12 Page 47 of 144 ---PAGE BREAK--- EXHIBIT 12 Page 48 of 144 ---PAGE BREAK--- EXHIBIT 12 Page 49 of 144 ---PAGE BREAK--- EXHIBIT 12 Page 50 of 144 ---PAGE BREAK--- EXHIBIT 12 Page 51 of 144 ---PAGE BREAK--- APPENDIX II Exploratory Boring and Test-Pit Logs EXHIBIT 12 Page 52 of 144 ---PAGE BREAK---                            
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9#I      , EXHIBIT 12 Page 75 of 144 ---PAGE BREAK--- KEY CHART 25  Conditions shown on boring and testpit logs represent our observations at the time and location of the fieldwork, modifications based on lab test, analysis, and geological and engineering judgment. These conditions may not exist at other times and locations, even in close proximity thereof. This information was gathered as part of our investigation, and we are not responsible for any use or interpretation of the information by others. RELATIVE DENSITY OR CONSISTENCY VERSUS SPT N-VALUE COARSE-GRAINED SOILS FINE-GRAINED SOILS DENSITY N (BLOWS/FT) FIELD TEST CONSISTENCY N (BLOWS/FT) FIELD TEST Very Loose 0 – 4 Easily penetrated with ½-inch reinforcing rod pushed by hand Very Soft 0 – 2 Easily penetrated several inches by thumb Loose 4 – 10 Difficult to penetrate with ½-inch reinforcing rod pushed by hand Soft 2 – 4 Easily penetrated one inch by thumb Medium -Dense 10 – 30 Easily penetrated with ½-inch rod driven with a 5-lb hammer Medium-Stiff 4 – 8 Penetrated over ½-inch by thumb with moderate effort Dense 30 – 50 Difficult to penetrate with ½-inch rod driven with a 5-lb hammer Stiff 8 – 15 Indented about ½-inch by thumb but penetrated with great effort Very Stiff 15 – 30 Readily indented by thumb Very Dense > 50 penetrated only a few inches with ½-inch rod driven with a 5-lb hammer Hard > 30 Indented with difficulty by thumbnail USCS SOIL CLASSIFICATION MAJOR DIVISIONS GROUP DESCRIPTION GW Well-graded Gravel Gravel (with little or no fines) GP Poorly Graded Gravel GM Silty Gravel Gravel and Gravelly Soils <50% coarse fraction passes #4 sieve Gravel (with >12% fines) GC Clayey Gravel SW Well-graded Sand Sand (with little or no fines) SP Poorly graded Sand SM Silty Sand Coarse- Grained Soils <50% passes #200 sieve Sand and Sandy Soils >50% coarse fraction passes #4 sieve Sand (with >12% fines) SC Clayey Sand ML Silt CL Lean Clay Silt and Clay Liquid Limit < 50 OL Organic Silt and Clay (low plasticity) MH Inorganic Silt CH Inorganic Clay Fine- Grained Soils >50% passes #200 sieve Silt and Clay Liquid Limit > 50 OH Organic Clay and Silt (med. to high plasticity) Highly Organic Soils PT Peat Top Soil MODIFIERS MOISTURE CONTENT DESCRIPTION RANGE DESCRIPTION FIELD OBSERVATION Trace Dry Absence of moisture, dusty, dry to the touch Little 5% – 12% Moist Damp but not visible water Some >12% Wet Visible free water MAJOR DIVISIONS WITH GRAIN SIZE SIEVE SIZE 12” 3” 3/4” 4 10 40 200 GRAIN SIZE (INCHES) 12 3 0.75 0.19 0.079 0.0171 0.0029 Gravel Sand Boulders Cobbles Coarse Fine Coarse Medium Fine Silt and Clay LOG SYMBOLS 2S 2” OD Split Spoon (SPT) 3S 3” OD Split Spoon NS Non-Standard Split Spoon ST Shelby Tube CR Core Run BG Bag Sample TV Torvane Reading PP Penetrometer Reading NR No Recovery GW Groundwater Table SOIL CLASSIFICATION INCLUDES 1. Group Name 2. Group Symbol 3. Color 4. Moisture content 5. Density / consistency 6. Cementation 7. Particle size (if applicable) 8. Odor (if present) 9. Comments EXHIBIT 12 Page 76 of 144 ---PAGE BREAK--- APPENDIX III Laboratory Testing Results EXHIBIT 12 Page 77 of 144 ---PAGE BREAK---               
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6 8 EXHIBIT 12 Page 84 of 144 ---PAGE BREAK--- APPENDIX IV Slope Stability Analyses EXHIBIT 12 Page 85 of 144 ---PAGE BREAK--- 1.9 1.9 1.9 1.9 Material Name Color Unit Weight (lbs/Ō3) Strength Type Cohesion (psf) Phi (deg) Loose Site Cast Fill 110 Mohr-Coulomb 0 28 Silt with Sand (low strength) 90 Mohr-Coulomb 0 29 Silt with Sand (relaƟvely high strength) 110 Mohr-Coulomb 0 34 Silty Gravel 125 Mohr-Coulomb 0 38 Safety Factor 0.0 0.3 0.5 0.8 1.0 1.3 1.5 1.8 2.0 2.3 2.5 2.8 3.0 3.3 3.5 3.8 4.0 4.3 4.5 4.8 5.0 5.3 5.5 5.8 6.0+ 800 775 750 725 700 675 650 -25 0 25 50 75 100 125 150 175 200 225 250 Analysis Description Local Static Slope Stability - Section A-A' Company GN Northern, Inc. Scale 1:328 Drawn By Yong Lee File Name SEC-AA' - Local.slim Date February 24, 2016 Project Proposed 'Sunrise Ridge' Residential Development S. Olympia Street, Kennewick, Washington SLIDEINTERPRET 7.011 EXHIBIT 12 Page 86 of 144 ---PAGE BREAK--- 2.1 2.1 2.1 2.1 Material Name Color Unit Weight (lbs/Ō3) Strength Type Cohesion (psf) Phi (deg) Loose Site Cast Fill 110 Mohr-Coulomb 0 28 Silty with Sand (low strength) 90 Mohr-Coulomb 0 29 Silty with Sand (relaƟvely high strength) 110 Mohr-Coulomb 0 34 Silty Gravel 125 Mohr-Coulomb 0 38 Safety Factor 0.0 0.3 0.5 0.8 1.0 1.3 1.5 1.8 2.0 2.3 2.5 2.8 3.0 3.3 3.5 3.8 4.0 4.3 4.5 4.8 5.0 5.3 5.5 5.8 6.0+ 900 850 800 750 700 650 -100 -50 0 50 100 150 200 250 300 Analysis Description Overall Static Slope Stability - Section A-A' Company GN Northern, Inc. Scale 1:540 Drawn By Yong Lee File Name SEC-AA' - Overall.slim Date February 24. 2016 Project Proposed 'Sunrise Ridge' Residential Development S. Olympia Street, Kennewick, Washington SLIDEINTERPRET 7.011 EXHIBIT 12 Page 87 of 144 ---PAGE BREAK--- 1.7 1.7 1.7 1.7 Material Name Color Unit Weight (lbs/Ō3) Strength Type Cohesion (psf) Phi (deg) Loose Site Cast Fill 110 Mohr-Coulomb 0 28 Silty with Sand (low strength) 90 Mohr-Coulomb 0 29 Silty with Sand (relaƟvely high strength) 110 Mohr-Coulomb 0 34 Silty Gravel 125 Mohr-Coulomb 0 38 Safety Factor 0.0 0.3 0.5 0.8 1.0 1.3 1.5 1.8 2.0 2.3 2.5 2.8 3.0 3.3 3.5 3.8 4.0 4.3 4.5 4.8 5.0 5.3 5.5 5.8 6.0+ 900 850 800 750 700 650 -100 -50 0 50 100 150 200 250 300 Analysis Description Overall Pseudo-Static Slope Stability - Section A-A' Company GN Northern, Inc. Scale 1:540 Drawn By Yong Lee File Name SEC-AA' - Overall_PS.slim Date February 24. 2016 Project Proposed 'Sunrise Ridge' Residential Development S. Olympia Street, Kennewick, Washington SLIDEINTERPRET 7.011 EXHIBIT 12 Page 88 of 144 ---PAGE BREAK--- 1.3 1.3 1.3 1.3 Material Name Color Unit Weight (lbs/Ō3) Strength Type Cohesion (psf) Phi (deg) Loose Site Cast Fill 110 Mohr-Coulomb 0 28 Silt with Sand (low strength) 90 Mohr-Coulomb 0 29 Silt with Sand (relaƟvely high strength) 110 Mohr-Coulomb 0 34 Silty Gravel 125 Mohr-Coulomb 0 38 Safety Factor 0.0 0.3 0.5 0.8 1.0 1.3 1.5 1.8 2.0 2.3 2.5 2.8 3.0 3.3 3.5 3.8 4.0 4.3 4.5 4.8 5.0 5.3 5.5 5.8 6.0+ 775 750 725 700 675 650 625 0 25 50 75 100 125 150 175 200 225 Analysis Description Local Static Slope Stability - Section B-B' Company GN Northern, Inc. Scale 1:307 Drawn By Yong Lee File Name SEC-BB' - Local.slim Date February 24. 2016 Project Proposed 'Sunrise Ridge' Residential Development S. Olympia Street, Kennewick, Washington SLIDEINTERPRET 7.011 EXHIBIT 12 Page 89 of 144 ---PAGE BREAK--- 2.4 2.4 2.4 2.4 Material Name Color Unit Weight (lbs/Ō3) Strength Type Cohesion (psf) Phi (deg) Loose Site Cast Fill 110 Mohr-Coulomb 0 28 Silt with Sand (low strength) 90 Mohr-Coulomb 0 29 Silt with Sand (relaƟvely high strength) 110 Mohr-Coulomb 0 34 Silty Gravel 125 Mohr-Coulomb 0 38 Safety Factor 0.0 0.3 0.5 0.8 1.0 1.3 1.5 1.8 2.0 2.3 2.5 2.8 3.0 3.3 3.5 3.8 4.0 4.3 4.5 4.8 5.0 5.3 5.5 5.8 6.0+ 850 800 750 700 650 -100 -50 0 50 100 150 200 250 300 Analysis Description Overall Static Slope Stability - Section B-B' Company GN Northern, Inc. Scale 1:489 Drawn By Yong Lee File Name SEC-BB' - Overall.slim Date February 24. 2016 Project Proposed 'Sunrise Ridge' Residential Development S. Olympia Street, Kennewick, Washington SLIDEINTERPRET 7.011 EXHIBIT 12 Page 90 of 144 ---PAGE BREAK--- 1.9 1.9 1.9 1.9 Material Name Color Unit Weight (lbs/Ō3) Strength Type Cohesion (psf) Phi (deg) Loose Site Cast Fill 110 Mohr-Coulomb 0 28 Silt with Sand (low strength) 90 Mohr-Coulomb 0 29 Silt with Sand (relaƟvely high strength) 110 Mohr-Coulomb 0 34 Silty Gravel 125 Mohr-Coulomb 0 38 0.06 Safety Factor 0.0 0.3 0.5 0.8 1.0 1.3 1.5 1.8 2.0 2.3 2.5 2.8 3.0 3.3 3.5 3.8 4.0 4.3 4.5 4.8 5.0 5.3 5.5 5.8 6.0+ 850 800 750 700 650 -100 -50 0 50 100 150 200 250 300 Analysis Description Overall Pseudo-Static Slope Stability - Section B-B' Company GN Northern, Inc. Scale 1:489 Drawn By Yong Lee File Name SEC-BB' - Overall_PS.slim Date February 24. 2016 Project Proposed 'Sunrise Ridge' Residential Development S. Olympia Street, Kennewick, Washington SLIDEINTERPRET 7.011 EXHIBIT 12 Page 91 of 144 ---PAGE BREAK--- 1.3 1.3 1.3 1.3 Material Name Color Unit Weight (lbs/Ō3) Strength Type Cohesion (psf) Phi (deg) Engineered Fill (silt w/sand) 118 Mohr-Coulomb 0 33 Fill (trash/debris) 115 Mohr-Coulomb 0 20 Silt with Sand (low strength) 90 Mohr-Coulomb 0 29 Silt with Sand (relaƟvely high strength) 110 Mohr-Coulomb 0 34 Silty Gravel 125 Mohr-Coulomb 0 38 Safety Factor 0.0 0.3 0.5 0.8 1.0 1.3 1.5 1.8 2.0 2.3 2.5 2.8 3.0 3.3 3.5 3.8 4.0 4.3 4.5 4.8 5.0 5.3 5.5 5.8 6.0+ 1000 900 800 700 600 0 100 200 300 400 500 600 700 Analysis Description Local Static Slope Stability - Section C-C' Company GN Northern, Inc. Scale 1:934 Drawn By Yong Lee File Name SEC-CC' - Local_1.slim Date February 24, 2016 Project Proposed 'Sunrise Ridge' Residential Development S. Olympia Street, Kennewick, Washington SLIDEINTERPRET 7.011 EXHIBIT 12 Page 92 of 144 ---PAGE BREAK--- 1.0 1.0 1.0 1.0 Material Name Color Unit Weight (lbs/Ō3) Strength Type Cohesion (psf) Phi (deg) Engineered Fill (silt w/sand) 118 Mohr-Coulomb 0 33 Fill (trash/debris) 115 Mohr-Coulomb 0 20 Silt with Sand (low strength) 90 Mohr-Coulomb 0 29 Silt with Sand (relaƟvely high strength) 110 Mohr-Coulomb 0 34 Silty Gravel 125 Mohr-Coulomb 0 38 Safety Factor 0.0 0.3 0.5 0.8 1.0 1.3 1.5 1.8 2.0 2.3 2.5 2.8 3.0 3.3 3.5 3.8 4.0 4.3 4.5 4.8 5.0 5.3 5.5 5.8 6.0+ 1000 900 800 700 600 0 100 200 300 400 500 600 700 Analysis Description Local Static Slope Stability - Section C-C' Company GN Northern, Inc. Scale 1:931 Drawn By Yong Lee File Name SEC-CC' - Local_2.slim Date February 24, 2016 Project Proposed 'Sunrise Ridge' Residential Development S. Olympia Street, Kennewick, Washington SLIDEINTERPRET 7.011 EXHIBIT 12 Page 93 of 144 ---PAGE BREAK--- 1.4 1.4 1.4 1.4 Material Name Color Unit Weight (lbs/Ō3) Strength Type Cohesion (psf) Phi (deg) Engineered Fill (silt w/sand) 118 Mohr-Coulomb 0 33 Fill (trash/debris) 115 Mohr-Coulomb 0 20 Silt with Sand (low strength) 90 Mohr-Coulomb 0 29 Silt with Sand (relaƟvely high strength) 110 Mohr-Coulomb 0 34 Silty Gravel 125 Mohr-Coulomb 0 38 Safety Factor 0.0 0.3 0.5 0.8 1.0 1.3 1.5 1.8 2.0 2.3 2.5 2.8 3.0 3.3 3.5 3.8 4.0 4.3 4.5 4.8 5.0 5.3 5.5 5.8 6.0+ 1000 900 800 700 600 0 100 200 300 400 500 600 700 Analysis Description Local Static Slope Stability - Section C-C' Company GN Northern, Inc. Scale 1:899 Drawn By Yong Lee File Name SEC-CC' - Local_3.slim Date February 24, 2016 Project Proposed 'Sunrise Ridge' Residential Development S. Olympia Street, Kennewick, Washington SLIDEINTERPRET 7.011 EXHIBIT 12 Page 94 of 144 ---PAGE BREAK--- 1.5 1.5 1.5 1.5 Material Name Color Unit Weight (lbs/Ō3) Strength Type Cohesion (psf) Phi (deg) Engineered Fill (silt w/sand) 118 Mohr-Coulomb 0 33 Fill (trash/debris) 115 Mohr-Coulomb 0 20 Silt with Sand (low strength) 90 Mohr-Coulomb 0 29 Silt with Sand (relaƟvely high strength) 110 Mohr-Coulomb 0 34 Silty Gravel 125 Mohr-Coulomb 0 38 Safety Factor 0.0 0.3 0.5 0.8 1.0 1.3 1.5 1.8 2.0 2.3 2.5 2.8 3.0 3.3 3.5 3.8 4.0 4.3 4.5 4.8 5.0 5.3 5.5 5.8 6.0+ 1000 900 800 700 600 0 100 200 300 400 500 600 700 Analysis Description Local Static Slope Stability - Section C-C' Company GN Northern, Inc. Scale 1:973 Drawn By Yong Lee File Name SEC-CC' - Local_4.slim Date February 24, 2016 Project Proposed 'Sunrise Ridge' Residential Development S. Olympia Street, Kennewick, Washington SLIDEINTERPRET 7.011 EXHIBIT 12 Page 95 of 144 ---PAGE BREAK--- 2.2 2.2 2.2 2.2 Material Name Color Unit Weight (lbs/Ō3) Strength Type Cohesion (psf) Phi (deg) Engineered Fill (silt w/sand) 118 Mohr-Coulomb 0 33 Fill (trash/debris) 115 Mohr-Coulomb 0 20 Silt with Sand (low strength) 90 Mohr-Coulomb 0 29 Silt with Sand (relaƟvely high strength) 110 Mohr-Coulomb 0 34 Silty Gravel 125 Mohr-Coulomb 0 38 Safety Factor 0.0 0.3 0.5 0.8 1.0 1.3 1.5 1.8 2.0 2.3 2.5 2.8 3.0 3.3 3.5 3.8 4.0 4.3 4.5 4.8 5.0 5.3 5.5 5.8 6.0+ 110 1000 900 800 700 600 -100 0 100 200 300 400 500 600 700 Analysis Description Overall Static Slope Stability - Section C-C' Company GN Northern, Inc. Scale 1:1034 Drawn By Yong Lee File Name SEC-CC' - Overall.slim Date February 24, 2016 Project Proposed 'Sunrise Ridge' Residential Development S. Olympia Street, Kennewick, Washington SLIDEINTERPRET 7.011 EXHIBIT 12 Page 96 of 144 ---PAGE BREAK--- 1.6 1.6 1.6 1.6 Material Name Color Unit Weight (lbs/Ō3) Strength Type Cohesion (psf) Phi (deg) Engineered Fill (silt w/sand) 118 Mohr-Coulomb 0 33 Fill (trash/debris) 115 Mohr-Coulomb 0 20 Silt with Sand (low strength) 90 Mohr-Coulomb 0 29 Silt with Sand (relaƟvely high strength) 110 Mohr-Coulomb 0 34 Silty Gravel 125 Mohr-Coulomb 0 38 Safety Factor 0.0 0.3 0.5 0.8 1.0 1.3 1.5 1.8 2.0 2.3 2.5 2.8 3.0 3.3 3.5 3.8 4.0 4.3 4.5 4.8 5.0 5.3 5.5 5.8 6.0+ 1100 1000 900 800 700 600 -100 0 100 200 300 400 500 600 700 800 Analysis Description Overall Pseudo-Static Slope Stability - Section C-C' Company GN Northern, Inc. Scale 1:1149 Drawn By Yong Lee File Name SEC-CC' - Overall_PS.slim Date February 24, 2016 Project Proposed 'Sunrise Ridge' Residential Development S. Olympia Street, Kennewick, Washington SLIDEINTERPRET 7.011 EXHIBIT 12 Page 97 of 144 ---PAGE BREAK--- 3.3 3.3 3.3 3.3 Material Name Color Unit Weight (lbs/Ō3) Strength Type Cohesion (psf) Phi (deg) Silt with Sand (low strength) 90 Mohr-Coulomb 0 29 Silt with Sand (relaƟvely high strength) 110 Mohr-Coulomb 0 34 Silty Gravel 125 Mohr-Coulomb 0 38 Safety Factor 0.0 0.3 0.5 0.8 1.0 1.3 1.5 1.8 2.0 2.3 2.5 2.8 3.0 3.3 3.5 3.8 4.0 4.3 4.5 4.8 5.0 5.3 5.5 5.8 6.0+ 900 850 800 750 -50 0 50 100 150 200 250 Analysis Description Local Static Slope Stability - Section D-D' Company GN Northern, Inc. Scale 1:407 Drawn By Yong Lee File Name SEC-DD' - Local.slim Date February, 24, 2016 Project Proposed 'Sunrise Ridge' Residential Development S. Olympia Street, Kennewick, Washington SLIDEINTERPRET 7.011 EXHIBIT 12 Page 98 of 144 ---PAGE BREAK--- 3.5 3.5 3.5 3.5 Material Name Color Unit Weight (lbs/Ō3) Strength Type Cohesion (psf) Phi (deg) Silt with Sand (low strength) 90 Mohr-Coulomb 0 29 Silt with Sand (relaƟvely high strength) 110 Mohr-Coulomb 0 34 Silty Gravel 125 Mohr-Coulomb 0 38 Safety Factor 0.0 0.3 0.5 0.8 1.0 1.3 1.5 1.8 2.0 2.3 2.5 2.8 3.0 3.3 3.5 3.8 4.0 4.3 4.5 4.8 5.0 5.3 5.5 5.8 6.0+ 90 850 800 750 -25 0 25 50 75 100 125 150 175 200 225 250 275 Analysis Description Overall Static Slope Stability - Section D-D' Company GN Northern, Inc. Scale 1:377 Drawn By Yong Lee File Name SEC-DD' - Overall.slim Date February, 24, 2016 Project Proposed 'Sunrise Ridge' Residential Development S. Olympia Street, Kennewick, Washington SLIDEINTERPRET 7.011 EXHIBIT 12 Page 99 of 144 ---PAGE BREAK--- 2.5 2.5 2.5 2.5 Material Name Color Unit Weight (lbs/Ō3) Strength Type Cohesion (psf) Phi (deg) Silt with Sand (low strength) 90 Mohr-Coulomb 0 29 Silt with Sand (relaƟvely high strength) 110 Mohr-Coulomb 0 34 Silty Gravel 125 Mohr-Coulomb 0 38 Safety Factor 0.0 0.3 0.5 0.8 1.0 1.3 1.5 1.8 2.0 2.3 2.5 2.8 3.0 3.3 3.5 3.8 4.0 4.3 4.5 4.8 5.0 5.3 5.5 5.8 6.0+ 900 850 800 750 -50 0 50 100 150 200 250 300 Analysis Description Overall Pseudo-Static Slope Stability - Section D-D' Company GN Northern, Inc. Scale 1:450 Drawn By Yong Lee File Name SEC-DD' - Overall_PS.slim Date February, 24, 2016 Project Proposed 'Sunrise Ridge' Residential Development S. Olympia Street, Kennewick, Washington SLIDEINTERPRET 7.011 EXHIBIT 12 Page 100 of 144 ---PAGE BREAK--- 1.9 1.9 1.9 1.9 Material Name Color Unit Weight (lbs/Ō3) Strength Type Cohesion (psf) Phi (deg) Silt with Sand (low strength) 90 Mohr-Coulomb 0 29 Silt with Sand (relaƟvely high strength) 110 Mohr-Coulomb 0 34 Silty Gravel 125 Mohr-Coulomb 0 38 Safety Factor 0.0 0.3 0.5 0.8 1.0 1.3 1.5 1.8 2.0 2.3 2.5 2.8 3.0 3.3 3.5 3.8 4.0 4.3 4.5 4.8 5.0 5.3 5.5 5.8 6.0+ 950 900 850 800 750 0 50 100 150 200 250 300 350 400 Analysis Description Local Static Slope Stability - Section E-E' Company GN Northern, Inc Scale 1:508 Drawn By Yong Lee File Name SEC-EE' - Local.slim Date February 24, 2016 Project Proposed 'Sunrise Ridge' Residential Development S. Olympia Street, Kennewick, Washington SLIDEINTERPRET 7.011 EXHIBIT 12 Page 101 of 144 ---PAGE BREAK--- 2.0 2.0 2.0 2.0 Material Name Color Unit Weight (lbs/Ō3) Strength Type Cohesion (psf) Phi (deg) Silt with Sand (low strength) 90 Mohr-Coulomb 0 29 Silt with Sand (relaƟvely high strength) 110 Mohr-Coulomb 0 34 Silty Gravel 125 Mohr-Coulomb 0 38 Safety Factor 0.0 0.3 0.5 0.8 1.0 1.3 1.5 1.8 2.0 2.3 2.5 2.8 3.0 3.3 3.5 3.8 4.0 4.3 4.5 4.8 5.0 5.3 5.5 5.8 6.0+ 110 1000 900 800 -100 -50 0 50 100 150 200 250 300 350 400 450 500 Analysis Description Overall Static Slope Stability - Section E-E' Company GN Northern, Inc Scale 1:737 Drawn By Yong Lee File Name SEC-EE' -Overall.slim Date February 24, 2016 Project Proposed 'Sunrise Ridge' Residential Development S. Olympia Street, Kennewick, Washington SLIDEINTERPRET 7.011 EXHIBIT 12 Page 102 of 144 ---PAGE BREAK--- 1.7 1.7 1.7 1.7 Material Name Color Unit Weight (lbs/Ō3) Strength Type Cohesion (psf) Phi (deg) Silt with Sand (low strength) 90 Mohr-Coulomb 0 29 Silt with Sand (relaƟvely high strength) 110 Mohr-Coulomb 0 34 Silty Gravel 125 Mohr-Coulomb 0 38 Safety Factor 0.0 0.3 0.5 0.8 1.0 1.3 1.5 1.8 2.0 2.3 2.5 2.8 3.0 3.3 3.5 3.8 4.0 4.3 4.5 4.8 5.0 5.3 5.5 5.8 6.0+ 110 1000 900 800 -100 -50 0 50 100 150 200 250 300 350 400 450 Analysis Description Overall Pseudo-Static Slope Stability - Section E-E' Company GN Northern, Inc Scale 1:737 Drawn By Yong Lee File Name SEC-EE' -Overall_PS.slim Date February 24, 2016 Project Proposed 'Sunrise Ridge' Residential Development S. Olympia Street, Kennewick, Washington SLIDEINTERPRET 7.011 EXHIBIT 12 Page 103 of 144 ---PAGE BREAK--- 1.1 1.1 1.1 1.1 Material Name Color Unit Weight (lbs/Ō3) Strength Type Cohesion (psf) Phi (deg) Silt with Sand (low strength) 90 Mohr-Coulomb 0 29 Silt with Sand (relaƟvely high strength) 110 Mohr-Coulomb 0 34 Silty Gravel 125 Mohr-Coulomb 0 38 Safety Factor 0.0 0.3 0.5 0.8 1.0 1.3 1.5 1.8 2.0 2.3 2.5 2.8 3.0 3.3 3.5 3.8 4.0 4.3 4.5 4.8 5.0 5.3 5.5 5.8 6.0+ 840 820 800 780 760 740 0 20 40 60 80 100 120 140 160 180 Analysis Description Local Static Slope Stability - Proposed 22-foot Tall Cut Slope Company GN Northern, Inc Scale 1:242 Drawn By Yong Lee File Name 22-foot_cut_slope - Local.slim Date February 24, 2016 Project Proposed 'Sunrise Ridge' Residential Development S. Olympia Street, Kennewick, Washington SLIDEINTERPRET 7.011 EXHIBIT 12 Page 104 of 144 ---PAGE BREAK--- 1.5 1.5 1.5 1.5 Material Name Color Unit Weight (lbs/Ō3) Strength Type Cohesion (psf) Phi (deg) Silt with Sand (low strength) 90 Mohr-Coulomb 0 29 Silt with Sand (relaƟvely high strength) 110 Mohr-Coulomb 0 34 Silty Gravel 125 Mohr-Coulomb 0 38 Safety Factor 0.0 0.3 0.5 0.8 1.0 1.3 1.5 1.8 2.0 2.3 2.5 2.8 3.0 3.3 3.5 3.8 4.0 4.3 4.5 4.8 5.0 5.3 5.5 5.8 6.0+ 860 840 820 800 780 760 740 -20 0 20 40 60 80 100 120 140 160 180 200 Analysis Description Overall Static Slope Stability - Proposed 22-foot Tall Cut Slope Company GN Northern, Inc Scale 1:271 Drawn By Yong Lee File Name 22-foot_cut_slope - Overall.slim Date February 24, 2016 Project Proposed 'Sunrise Ridge' Residential Development S. Olympia Street, Kennewick, Washington SLIDEINTERPRET 7.011 EXHIBIT 12 Page 105 of 144 ---PAGE BREAK--- 1.3 1.3 1.3 1.3 Material Name Color Unit Weight (lbs/Ō3) Strength Type Cohesion (psf) Phi (deg) Silt with Sand (low strength) 90 Mohr-Coulomb 0 29 Silt with Sand (relaƟvely high strength) 110 Mohr-Coulomb 0 34 Silty Gravel 125 Mohr-Coulomb 0 38 Safety Factor 0.0 0.3 0.5 0.8 1.0 1.3 1.5 1.8 2.0 2.3 2.5 2.8 3.0 3.3 3.5 3.8 4.0 4.3 4.5 4.8 5.0 5.3 5.5 5.8 6.0+ 860 840 820 800 780 760 740 -20 0 20 40 60 80 100 120 140 160 180 Analysis Description Overall Pseudo-Static Slope Stability - Proposed 22-foot Tall Cut Slope Company GN Northern, Inc Scale 1:271 Drawn By Yong Lee File Name 22-foot_cut_slope - Overall_PS.slim Date February 24, 2016 Project Proposed 'Sunrise Ridge' Residential Development S. Olympia Street, Kennewick, Washington SLIDEINTERPRET 7.011 EXHIBIT 12 Page 106 of 144 ---PAGE BREAK--- 1.3 1.3 300.00 lbs/ft2 1.3 1.3 Existing Ground Surface Material Name Color Unit Weight (lbs/Ō3) Strength Type Cohesion (psf) Phi (deg) Engineered Fill (silt wi/ sand) 118 Mohr-Coulomb 0 33 Silt with Sand (low strength) 90 Mohr-Coulomb 0 29 Silt with Sand (relaƟvely high strength) 110 Mohr-Coulomb 0 34 Safety Factor 0.0 0.3 0.5 0.8 1.0 1.3 1.5 1.8 2.0 2.3 2.5 2.8 3.0 3.3 3.5 3.8 4.0 4.3 4.5 4.8 5.0 5.3 5.5 5.8 6.0+ 850 800 750 700 -100 -50 0 50 100 150 200 250 Analysis Description Local Static Slope Stability - Proposed 38-foot Tall Fill Slope Company GN Northern, Inc Scale 1:431 Drawn By Yong Lee File Name 38-foot_fill_slope_33 - Local.slim Date February 24, 2016 Project Proposed 'Sunrise Ridge' Residential Development S. Olympia Street, Kennewick, Washington SLIDEINTERPRET 7.011 EXHIBIT 12 Page 107 of 144 ---PAGE BREAK--- 1.4 1.4 300.00 lbs/ft2 1.4 1.4 Existing Ground Surface 1 2 Material Name Color Unit Weight (lbs/Ō3) Strength Type Cohesion (psf) Phi (deg) Engineered Fill (silty w/ sand) 118 Mohr-Coulomb 0 33 Silt with Sand (low strength) 90 Mohr-Coulomb 0 29 Silt with Sand (relaƟvely high strength) 110 Mohr-Coulomb 0 34 Safety Factor 0.0 0.3 0.5 0.8 1.0 1.3 1.5 1.8 2.0 2.3 2.5 2.8 3.0 3.3 3.5 3.8 4.0 4.3 4.5 4.8 5.0 5.3 5.5 5.8 6.0+ 780 760 740 720 700 680 660 -20 0 20 40 60 80 100 120 140 160 180 200 Analysis Description Overall Static Slope Stability - Proposed 38-foot Tall Fill Slope Company GN Northern, Inc Scale 1:271 Drawn By Yong Lee File Name 38-foot_fill_slope_33 - Overall.slim Date February 24, 2016 Project Proposed 'Sunrise Ridge' Residential Development S. Olympia Street, Kennewick, Washington SLIDEINTERPRET 7.011 EXHIBIT 12 Page 108 of 144 ---PAGE BREAK--- 1.2 1.2 300.00 lbs/ft2 1.2 1.2 Existing Ground Surface Material Name Color Unit Weight (lbs/Ō3) Strength Type Cohesion (psf) Phi (deg) Engineered Fill (silty w/ sand) 118 Mohr-Coulomb 0 33 Silt with Sand (low strength) 90 Mohr-Coulomb 0 29 Silt with Sand (relaƟvely high strength) 110 Mohr-Coulomb 0 34 Safety Factor 0.0 0.3 0.5 0.8 1.0 1.3 1.5 1.8 2.0 2.3 2.5 2.8 3.0 3.3 3.5 3.8 4.0 4.3 4.5 4.8 5.0 5.3 5.5 5.8 6.0+ 780 760 740 720 700 680 660 -20 0 20 40 60 80 100 120 140 160 180 20 Analysis Description Overall Pseudo-Static Slope Stability - Proposed 38-foot Tall Fill Slope Company GN Northern, Inc Scale 1:271 Drawn By Yong Lee File Name 38-foot_fill_slope_33 - Overall_PS.slim Date February 24, 2016 Project Proposed 'Sunrise Ridge' Residential Development S. Olympia Street, Kennewick, Washington SLIDEINTERPRET 7.011 EXHIBIT 12 Page 109 of 144 ---PAGE BREAK--- 1.4 1.4 300.00 lbs/ft2 1.4 1.4 Material Name Color Unit Weight (lbs/Ō3) Strength Type Cohesion (psf) Phi (deg) Engineered Fill (silt w/sand) 118 Mohr-Coulomb 0 33 Silt with Sand (low strength) 90 Mohr-Coulomb 0 29 Silt with Sand (relaƟvely high strength) 110 Mohr-Coulomb 0 34 Existing Ground Surface Safety Factor 0.0 0.3 0.5 0.8 1.0 1.3 1.5 1.8 2.0 2.3 2.5 2.8 3.0 3.3 3.5 3.8 4.0 4.3 4.5 4.8 5.0 5.3 5.5 5.8 6.0+ 740 720 700 680 660 -20 0 20 40 60 80 100 Analysis Description Local Static Slope Stability - Proposed 15-foot Tall Fill Slope Company GN Northern, Inc Scale 1:163 Drawn By Yong Lee File Name 15-foot_fill_slope - Overall.slim Date February 24, 2016 Project Proposed 'Sunrise Ridge' Residential Development S. Olympia Street, Kennewick, Washington SLIDEINTERPRET 7.011 EXHIBIT 12 Page 110 of 144 ---PAGE BREAK--- 1.5 1.5 300.00 lbs/ft2 1.5 1.5 Material Name Color Unit Weight (lbs/Ō3) Strength Type Cohesion (psf) Phi (deg) Engineered Fill (silt w/sand) 118 Mohr-Coulomb 0 33 Silt with Sand (low strength) 90 Mohr-Coulomb 0 29 Silt with Sand (relaƟvely high strength) 110 Mohr-Coulomb 0 34 Existing Ground Surface Safety Factor 0.0 0.3 0.5 0.8 1.0 1.3 1.5 1.8 2.0 2.3 2.5 2.8 3.0 3.3 3.5 3.8 4.0 4.3 4.5 4.8 5.0 5.3 5.5 5.8 6.0+ 720 700 680 660 -10 0 10 20 30 40 50 60 70 80 90 100 110 Analysis Description Overall Static Slope Stability - Proposed 15-foot Tall Fill Slope Company GN Northern, Inc Scale 1:147 Drawn By Yong Lee File Name 15-foot_fill_slope - Overall.slim Date February 24, 2016 Project Proposed 'Sunrise Ridge' Residential Development S. Olympia Street, Kennewick, Washington SLIDEINTERPRET 7.011 EXHIBIT 12 Page 111 of 144 ---PAGE BREAK--- 1.3 1.3 300.00 lbs/ft2 1.3 1.3 Material Name Color Unit Weight (lbs/Ō3) Strength Type Cohesion (psf) Phi (deg) Engineered Fill (silt w/sand) 118 Mohr-Coulomb 0 33 Silt with Sand (low strength) 90 Mohr-Coulomb 0 29 Silt with Sand (relaƟvely high strength) 110 Mohr-Coulomb 0 34 Existing Ground Surface Safety Factor 0.0 0.3 0.5 0.8 1.0 1.3 1.5 1.8 2.0 2.3 2.5 2.8 3.0 3.3 3.5 3.8 4.0 4.3 4.5 4.8 5.0 5.3 5.5 5.8 6.0+ 720 710 700 690 680 670 660 -10 0 10 20 30 40 50 60 70 80 90 100 Analysis Description Overall Pseudo-Static Slope Stability - Proposed 15-foot Tall Fill Slope Company GN Northern, Inc Scale 1:132 Drawn By Yong Lee File Name 15-foot_fill_slope - Overall_PS.slim Date February 24, 2016 Project Proposed 'Sunrise Ridge' Residential Development S. Olympia Street, Kennewick, Washington SLIDEINTERPRET 7.011 EXHIBIT 12 Page 112 of 144 ---PAGE BREAK--- 1.4 1.4 300.00 lbs/ft2 1.4 1.4 Material Name Color Unit Weight (lbs/Ō3) Strength Type Cohesion (psf) Phi (deg) Engineered Fill (granular soils) 120 Mohr-Coulomb 0 35 Silt with Sand (low strength) 90 Mohr-Coulomb 0 29 Silt with Sand (relaƟvely high strength) 110 Mohr-Coulomb 0 34 Existing Ground Surface Safety Factor 0.0 0.3 0.5 0.8 1.0 1.3 1.5 1.8 2.0 2.3 2.5 2.8 3.0 3.3 3.5 3.8 4.0 4.3 4.5 4.8 5.0 5.3 5.5 5.8 6.0+ 800 775 750 725 700 675 650 -80 -60 -40 -20 0 20 40 60 80 100 120 140 160 Analysis Description Local Static Slope Stability - Proposed 25-foot Tall Granular Fill Slope Company GN Northern, Inc Scale 1:302 Drawn By Yong Lee File Name 25-foot_fill_slope_35 - Local.slim Date February 24, 2016 Project Proposed 'Sunrise Ridge' Residential Development S. Olympia Street, Kennewick, Washington SLIDEINTERPRET 7.011 EXHIBIT 12 Page 113 of 144 ---PAGE BREAK--- 1.5 1.5 300.00 lbs/ft2 1.5 1.5 Material Name Color Unit Weight (lbs/Ō3) Strength Type Cohesion (psf) Phi (deg) Engineered Fill (granular soils) 120 Mohr-Coulomb 0 35 Silt with Sand (low strength) 90 Mohr-Coulomb 0 29 Silt with Sand (relaƟvely high strength) 110 Mohr-Coulomb 0 34 Existing Ground Surface Safety Factor 0.0 0.3 0.5 0.8 1.0 1.3 1.5 1.8 2.0 2.3 2.5 2.8 3.0 3.3 3.5 3.8 4.0 4.3 4.5 4.8 5.0 5.3 5.5 5.8 6.0+ 740 720 700 680 660 0 20 40 60 80 100 120 140 Analysis Description Overall Static Slope Stability - Proposed 25-foot Tall Granular Fill Slope Company GN Northern, Inc Scale 1:191 Drawn By Yong Lee File Name 25-foot_fill_slope_35 - Overall.slim Date February 24, 2016 Project Proposed 'Sunrise Ridge' Residential Development S. Olympia Street, Kennewick, Washington SLIDEINTERPRET 7.011 EXHIBIT 12 Page 114 of 144 ---PAGE BREAK--- 1.3 1.3 300.00 lbs/ft2 1.3 1.3 Material Name Color Unit Weight (lbs/Ō3) Strength Type Cohesion (psf) Phi (deg) Engineered Fill (granular soils) 120 Mohr-Coulomb 0 35 Silt with Sand (low strength) 90 Mohr-Coulomb 0 29 Silt with Sand (relaƟvely high strength) 110 Mohr-Coulomb 0 34 Existing Ground Surface Safety Factor 0.0 0.3 0.5 0.8 1.0 1.3 1.5 1.8 2.0 2.3 2.5 2.8 3.0 3.3 3.5 3.8 4.0 4.3 4.5 4.8 5.0 5.3 5.5 5.8 6.0+ 740 720 700 680 660 0 20 40 60 80 100 120 140 Analysis Description Overall Pseudo-Static Slope Stability - Proposed 25-foot Tall Granular Fill Slope Company GN Northern, Inc Scale 1:191 Drawn By Yong Lee File Name 25-foot_fill_slope_35 - Overall_PS.slim Date February 24, 2016 Project Proposed 'Sunrise Ridge' Residential Development S. Olympia Street, Kennewick, Washington SLIDEINTERPRET 7.011 EXHIBIT 12 Page 115 of 144 ---PAGE BREAK--- APPENDIX V Site & Exploration Photographs EXHIBIT 12 Page 116 of 144 ---PAGE BREAK--- Site conditions near southern portion of site looking north Site conditions near southern portion of site looking east Site conditions near southern portion of site looking west Site conditions on western edge of site looking SW Site conditions near southern portion of site looking NE Site conditions near center of site looking NE Site conditions near center of site looking SW Site conditions near SE portion of site along access road Job Number: 216-672 Site & Exploration Photographs Proposed ‘Sunrise Ridge’ Residential Development S. Olympia Street Kennewick, Washington Date 2/22/2016 Mounted By: JS Reviewed By: MYM Plate 1 EXHIBIT 12 Page 117 of 144 ---PAGE BREAK--- Site conditions near eastern portion of site looking SW Slope conditions near eastern portion of site looking NE Site/slope conditions near eastern portion of site looking NE Site/slope conditions towards northern end of access road, looking SE Slope conditions adjacent to KID Canal, east edge of site looking south Site conditions parallel to KID Canal, NW edge of site looking SE Site/slope conditions near northern portion of site looking NW Site conditions along eastern property boundary looking north Job Number: 216-672 Site & Exploration Photographs Proposed ‘Sunrise Ridge’ Residential Development S. Olympia Street Kennewick, Washington Date 2/22/2016 Mounted By: JS Reviewed By: MYM Plate 2 EXHIBIT 12 Page 118 of 144 ---PAGE BREAK--- Site conditions near northern portion of site looking NE Site/slope conditions near northern portion of site along access road Gully erosion noted in south-central portion of site along access road Gully erosion noted in south-central portion of site along access road Gully erosion noted in south-central portion of site along access road Gully erosion noted along filled slope face in central portion of site Gully erosion noted along filled slope face in central portion of site Stockpile soil/construction debris in north-central portion of site Job Number: 216-672 Site & Exploration Photographs Proposed ‘Sunrise Ridge’ Residential Development S. Olympia Street Kennewick, Washington Date 2/22/2016 Mounted By: JS Reviewed By: MYM Plate 3 EXHIBIT 12 Page 119 of 144 ---PAGE BREAK--- Construction debris in north-central portion of site looking SW Construction materials along access road, north-central portion of site Drilling boring B-1 in northern portion of site Drilling boring B-2 in northern portion of site Drilling boring B-7 in southern portion of site Drilling boring B-8 in southern portion of site Split-spoon sample recovered from B-1 @ 15’ Split-spoon sample recovered from B-2 @ 7.5’ Job Number: 216-672 Site & Exploration Photographs Proposed ‘Sunrise Ridge’ Residential Development S. Olympia Street Kennewick, Washington Date 2/22/2016 Mounted By: JS Reviewed By: MYM Plate 4 EXHIBIT 12 Page 120 of 144 ---PAGE BREAK--- Split-spoon sample recovered from B-3 @ 2.5’ Split-spoon sample recovered from B-4 @ 25’ Split-spoon sample recovered from B-7 @ 17.5’ Split-spoon sample recovered from B-8 @ 25’ Split-spoon sample recovered from B-9 @ 40’ Excavating test-pit TP-2 in southern portion of site Soil profile exposed in test-pit TP-2 Soil profile exposed in test-pit TP-3 Job Number: 216-672 Site & Exploration Photographs Proposed ‘Sunrise Ridge’ Residential Development S. Olympia Street Kennewick, Washington Date 2/22/2016 Mounted By: JS Reviewed By: MYM Plate 5 EXHIBIT 12 Page 121 of 144 ---PAGE BREAK--- Excavating test-pit TP-4 near central portion of site Soil profile exposed in test-pit TP-4 Excavating test-pit TP-8 in eastern portion of site Soil profile exposed in test-pit TP-8 (note trash/debris) Uncontrolled fill with concrete debris from TP-8 Excavating test-pit TP-11 in NE portion of site Very fine sand with lenses of coarse sand from TP-11 Excavating test-pit TP-13 in northern portion of site Job Number: 216-672 Site & Exploration Photographs Proposed ‘Sunrise Ridge’ Residential Development S. Olympia Street Kennewick, Washington Date 2/22/2016 Mounted By: JS Reviewed By: MYM Plate 6 EXHIBIT 12 Page 122 of 144 ---PAGE BREAK--- Soil profile exposed in test-pit TP-14 Drilling for infiltration test hole P-1 in northern portion of site Infiltration testing at P-1 Pea gravel placed around test pipe in bottom of hole Drilling for infiltration test hole P-2 in NE portion of site Infiltration testing at P-3 near north-central portion of site Drilling for infiltration test hole P-4 near western portion of site Refilling P-4 from water tank Job Number: 216-672 Site & Exploration Photographs Proposed ‘Sunrise Ridge’ Residential Development S. Olympia Street Kennewick, Washington Date 2/22/2016 Mounted By: JS Reviewed By: MYM Plate 7 EXHIBIT 12 Page 123 of 144 ---PAGE BREAK--- APPENDIX VI Historic Aerial Photographs EXHIBIT 12 Page 124 of 144 ---PAGE BREAK--- HistoricPlus.com [PHONE REDACTED] Historic Plus Research Service Order ID: H1979.1000 Completed: 10/28/2013 AERIAL PHOTO SEARCH for the site: OLYMPIA STREET PARCEL (213-422) 5353 S OLYMPIA ST KENNEWICK, WA99337 46.160486 I -119.134236 Search Results Summary Date Source Scale Comment 2011_ National Agriculture Information Program (NAIP) _ 700_ _ 2005_ National Agriculture Information Program (NAIP) _ 700_ _ 1996_ US Geological Survey (USGS) _ 700_ _ 1988_ US Geological Survey (USGS) _ 700_ _ 1952_ Army Mapping Service (AMS) _ 700_ BEST COPY AVAILABLE_ EXHIBIT 12 Page 125 of 144 ---PAGE BREAK--- Date: Scale: Source: JobID: Project Number: 2011 1"=700' NAIP H1979.1000 213-422 Site Location: Comment: 5353 S OLYMPIA ST KENNEWICK,WA _ Date: Scale: Source: JobID: Project Number: 2011 1"=700' NAIP H1979.1000 213-422 Site Location: Comment: 5353 S OLYMPIA ST KENNEWICK,WA _ EXHIBIT 12 Page 126 of 144 ---PAGE BREAK--- Date: Scale: Source: JobID: Project Number: 2005 1"=700' NAIP H1979.1000 213-422 Site Location: Comment: 5353 S OLYMPIA ST KENNEWICK,WA _ Date: Scale: Source: JobID: Project Number: 2005 1"=700' NAIP H1979.1000 213-422 Site Location: Comment: 5353 S OLYMPIA ST KENNEWICK,WA _ EXHIBIT 12 Page 127 of 144 ---PAGE BREAK--- Date: Scale: Source: JobID: Project Number: 1996 1"=700' USGS H1979.1000 213-422 Site Location: Comment: 5353 S OLYMPIA ST KENNEWICK,WA _ Date: Scale: Source: JobID: Project Number: 1996 1"=700' USGS H1979.1000 213-422 Site Location: Comment: 5353 S OLYMPIA ST KENNEWICK,WA _ EXHIBIT 12 Page 128 of 144 ---PAGE BREAK--- Date: Scale: Source: JobID: Project Number: 1988 1"=700' USGS H1979.1000 213-422 Site Location: Comment: 5353 S OLYMPIA ST KENNEWICK,WA _ Date: Scale: Source: JobID: Project Number: 1988 1"=700' USGS H1979.1000 213-422 Site Location: Comment: 5353 S OLYMPIA ST KENNEWICK,WA _ EXHIBIT 12 Page 129 of 144 ---PAGE BREAK--- Date: Scale: Source: JobID: Project Number: 1952 1"=700' AMS H1979.1000 213-422 Site Location: Comment: 5353 S OLYMPIA ST KENNEWICK,WA BEST COPY AVAILABLE Date: Scale: Source: JobID: Project Number: 1952 1"=700' AMS H1979.1000 213-422 Site Location: Comment: 5353 S OLYMPIA ST KENNEWICK,WA BEST COPY AVAILABLE EXHIBIT 12 Page 130 of 144 ---PAGE BREAK--- APPENDIX VII FEMA Flood Map EXHIBIT 12 Page 131 of 144 ---PAGE BREAK--- EXHIBIT 12 Page 132 of 144 ---PAGE BREAK--- APPENDIX VIII NRCS Soil Survey EXHIBIT 12 Page 133 of 144 ---PAGE BREAK--- United States Department of Agriculture A product of the National Cooperative Soil Survey, a joint effort of the United States Department of Agriculture and other Federal agencies, State agencies including the Agricultural Experiment Stations, and local participants Custom Soil Resource Report for Benton County Area, Washington Sunrise Ridge Natural Resources Conservation Service February 10, 2016 EXHIBIT 12 Page 134 of 144 ---PAGE BREAK--- 6 Custom Soil Resource Report Soil Map 5113800 5113900 5114000 5114100 5114200 5114300 5114400 5114500 5114600 5113800 5113900 5114000 5114100 5114200 5114300 5114400 5114500 5114600 334900 335000 335100 335200 335300 335400 334900 335000 335100 335200 335300 335400 46° 9' 54'' N 119° 8' 20'' W 46° 9' 54'' N 119° 7' 51'' W 46° 9' 27'' N 119° 8' 20'' W 46° 9' 27'' N 119° 7' 51'' W N Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 11N WGS84 0 150 300 600 900 Feet 0 50 100 200 300 Meters Map Scale: 1:4,070 if printed on A portrait (8.5" x 11") sheet. EXHIBIT 12 Page 135 of 144 ---PAGE BREAK--- Benton County Area, Washington ShF—Shano silt loam, 30 to 65 percent slopes Map Unit Setting National map unit symbol: 2bdx Elevation: 500 to 2,300 feet Mean annual precipitation: 6 to 10 inches Mean annual air temperature: 46 to 54 degrees F Frost-free period: 125 to 200 days Farmland classification: Not prime farmland Map Unit Composition Shano and similar soils: 100 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Shano Setting Landform: Hillslopes Parent material: Loess Typical profile H1 - 0 to 8 inches: silt loam H2 - 8 to 33 inches: silt loam H3 - 33 to 60 inches: silt loam Properties and qualities Slope: 30 to 65 percent Depth to restrictive feature: More than 80 inches Natural drainage class: Well drained Capacity of the most limiting layer to transmit water (Ksat): Moderately high to high (0.57 to 1.98 in/hr) Depth to water table: More than 80 inches Frequency of flooding: None Frequency of ponding: None Calcium carbonate, maximum in profile: 15 percent Salinity, maximum in profile: Nonsaline to very saline (0.0 to 2.0 mmhos/cm) Available water storage in profile: High (about 11.4 inches) Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 7e Hydrologic Soil Group: B Ecological site: LOAMY 6-10 PZ (R007XY102WA) WdAB—Warden silt loam, 0 to 5 percent slopes Map Unit Setting National map unit symbol: 2bfk Elevation: 600 to 1,300 feet Custom Soil Resource Report 10 EXHIBIT 12 Page 136 of 144 ---PAGE BREAK--- Mean annual precipitation: 6 to 9 inches Mean annual air temperature: 48 to 52 degrees F Frost-free period: 135 to 200 days Farmland classification: Prime farmland if irrigated Map Unit Composition Warden and similar soils: 100 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Warden Setting Landform: Terraces Parent material: Loess over lacustrine deposits Typical profile H1 - 0 to 9 inches: silt loam H2 - 9 to 19 inches: silt loam H3 - 19 to 60 inches: stratified very fine sandy loam to silt loam Properties and qualities Slope: 0 to 5 percent Depth to restrictive feature: More than 80 inches Natural drainage class: Well drained Capacity of the most limiting layer to transmit water (Ksat): Moderately high to high (0.57 to 1.98 in/hr) Depth to water table: More than 80 inches Frequency of flooding: None Frequency of ponding: None Calcium carbonate, maximum in profile: 30 percent Salinity, maximum in profile: Nonsaline to very saline (0.0 to 2.0 mmhos/cm) Available water storage in profile: High (about 11.8 inches) Interpretive groups Land capability classification (irrigated): 2e Land capability classification (nonirrigated): 6e Hydrologic Soil Group: B Ecological site: LOAMY 6-10 PZ (R007XY102WA) WdC—Warden silt loam, 5 to 8 percent slopes Map Unit Setting National map unit symbol: 2bfm Elevation: 600 to 1,300 feet Mean annual precipitation: 6 to 9 inches Mean annual air temperature: 48 to 52 degrees F Frost-free period: 135 to 200 days Farmland classification: Farmland of statewide importance Map Unit Composition Warden and similar soils: 100 percent Estimates are based on observations, descriptions, and transects of the mapunit. Custom Soil Resource Report 11 EXHIBIT 12 Page 137 of 144 ---PAGE BREAK--- Description of Warden Setting Landform: Terraces Parent material: Loess over lacustrine deposits Typical profile H1 - 0 to 9 inches: silt loam H2 - 9 to 19 inches: silt loam H3 - 19 to 60 inches: stratified very fine sandy loam to silt loam Properties and qualities Slope: 5 to 8 percent Depth to restrictive feature: More than 80 inches Natural drainage class: Well drained Capacity of the most limiting layer to transmit water (Ksat): Moderately high to high (0.57 to 1.98 in/hr) Depth to water table: More than 80 inches Frequency of flooding: None Frequency of ponding: None Calcium carbonate, maximum in profile: 30 percent Salinity, maximum in profile: Nonsaline to very saline (0.0 to 2.0 mmhos/cm) Available water storage in profile: High (about 11.8 inches) Interpretive groups Land capability classification (irrigated): 3e Land capability classification (nonirrigated): 6e Hydrologic Soil Group: B WdE3—Warden silt loam, 15 to 30 percent slopes, severely eroded Map Unit Setting National map unit symbol: 2bfp Elevation: 600 to 1,300 feet Mean annual precipitation: 6 to 9 inches Mean annual air temperature: 48 to 52 degrees F Frost-free period: 135 to 200 days Farmland classification: Farmland of unique importance Map Unit Composition Warden and similar soils: 100 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Warden Setting Landform: Terraces Parent material: Loess over lacustrine deposits Typical profile H1 - 0 to 2 inches: silt loam H2 - 2 to 12 inches: silt loam Custom Soil Resource Report 12 EXHIBIT 12 Page 138 of 144 ---PAGE BREAK--- H3 - 12 to 60 inches: stratified very fine sandy loam to silt loam Properties and qualities Slope: 15 to 30 percent Depth to restrictive feature: More than 80 inches Natural drainage class: Well drained Capacity of the most limiting layer to transmit water (Ksat): Moderately high to high (0.57 to 1.98 in/hr) Depth to water table: More than 80 inches Frequency of flooding: None Frequency of ponding: None Calcium carbonate, maximum in profile: 30 percent Salinity, maximum in profile: Nonsaline to very saline (0.0 to 2.0 mmhos/cm) Available water storage in profile: High (about 11.8 inches) Interpretive groups Land capability classification (irrigated): 6e Land capability classification (nonirrigated): 6e Hydrologic Soil Group: B Ecological site: LOAMY 6-10 PZ (R007XY102WA) Custom Soil Resource Report 13 EXHIBIT 12 Page 139 of 144 ---PAGE BREAK--- APPENDIX IX Washington Department of Ecology Well Log EXHIBIT 12 Page 140 of 144 ---PAGE BREAK--- EXHIBIT 12 Page 141 of 144 ---PAGE BREAK--- APPENDIX X Preliminary Site Grading Plan EXHIBIT 12 Page 142 of 144 ---PAGE BREAK--- Sunrise Ridge Subdivision A project in the City of , WA Existing conditions-north for: FEB 18, 2016 Date: 0032.00 JF Eng. Job # DJ Sunrise Development LLC 5602 S Newport Pl PR Kennewick, WA 99337-4632 1 A B C D E F G H I J K L 3 2 5 4 7 6 9 8 11 10 13 12 15 14 16 5220 S. Auburn Pl Kennewick, WA 99337 (509) 551-8174 PHN www.JFEngineering.pro ENGINEERING, PLLC Checked by: JEF Drawn by: JEF PRELIMINARY S T A T E O F W A S H N G T O N J O H N E R I C F E T T E R O L F D E R E T S I G E R 38322 R E E N I G N E L A N O I I S S E F O R P C300 Scale V: N/A Scale H: 1"=80' Know what's R S OLYMPIA ST USBR (KENNEWICK IRRIGATION DISTRICT) W 53rd AVE S OLYMPIA ST EXISTING PUBLIC SANITARY SEWER MANHOLE EXISTING PUBLIC WATER MAIN EXISTING PUBLIC STORM SEWER SYSTEM W 52nd AVE MATCH LINE SEE C201 MATCH LINE SEE RIGHT MATCH LINE SEE LEFT EXISTING PUBLIC SANITARY SEWER MANHOLE EXISTING PUBLIC SANITARY SEWER MANHOLE EXISTING PUBLIC SANITARY SEWER MANHOLE EXISTING HOME EXISTING HOME EXISTING HOME EXISTING HOME CITY WATER TANK EXISTING U.G. PUD POWER EXISTING POWER POLE S OLYMPIA ST USBR (KENNEWICK IRRIGATION DISTRICT) EXISTING PUBLIC SANITARY SEWER MANHOLE EXISTING PUBLIC SANITARY SEWER MANHOLE EXISTING STREET LIGHT EXISTING STREET LIGHT EXISTING CONCRETE SIDEWALK (PAVED) PROPOSED FG CONTOURS EXISTING GROUND CONTOURS STREET PHASE 1 WILL CONSTRUCT A TEMPORARY CUL-DE-SAC AT THIS LOCATION NOTES: 1. IN ORDER TO ACHIEVE PROPOSED GRADES, MATERIAL MAY BE MOVED FROM FUTURE PHASES TO ACCOMPLISH THE GRADES OF CURRENT PHASES. 2. ALL DISTURBED AREAS WILL BE STABILIZED AT THE COMPLETION OF GRADING EACH PHASE. 3. ALL FILL MATERIAL WILL BE GENERATED FROM ONSITE CUT LOCATIONS. NO IMPORTED FILL MATERIAL IS PLANNED. 1 2 3 4 5 6 7 8 9 10 11 42 43 44 EXHIBIT 12 Page 143 of 144 ---PAGE BREAK--- Sunrise Ridge Subdivision A project in the City of , WA Existing conditions-south for: FEB 19, 2016 Date: 0032.00 JF Eng. Job # DJ Sunrise Development LLC 5602 S Newport Pl PR Kennewick, WA 99337-4632 1 A B C D E F G H I J K L 3 2 5 4 7 6 9 8 11 10 13 12 15 14 16 5220 S. Auburn Pl Kennewick, WA 99337 (509) 551-8174 PHN www.JFEngineering.pro ENGINEERING, PLLC Checked by: JEF Drawn by: JEF PRELIMINARY S T A T E O F W A S H N G T O N J O H N E R I C F E T T E R O L F D E R E T S I G E R 38322 R E E N I G N E L A N O I I S S E F O R P C301 Scale V: N/A Scale H: 1"=80' Know what's R S NEWPORT PL (PR) TO HWY 397 S OLYMPIA ST EXISTING STREET INTERSECTION MATCH LINE SEE C200 EXISTING HOME EXISTING HOME EXISTING HOME EXISTING HOME EXISTING HOME EXISTING HOME (PAVED) EXISTING DRIVEWAY VACANT VACANT VACANT EXISTING PUBLIC SANITARY SEWER EXISTING PUBLIC WATER SERVICE DRIVEWAY DRIVEWAY DRIVEWAY EXISTING PUBLIC SANITARY SEWER EXISTING PUBLIC WATER SERVICE EXISTING FIRE HYDRANT EXISTING CITY WATER LINE STUB NOTES: 1. IN ORDER TO ACHIEVE PROPOSED GRADES, MATERIAL MAY BE MOVED FROM FUTURE PHASES TO ACCOMPLISH THE GRADES OF CURRENT PHASES. 2. ALL DISTURBED AREAS WILL BE STABILIZED AT THE COMPLETION OF GRADING EACH PHASE. 3. ALL FILL MATERIAL WILL BE GENERATED FROM ONSITE CUT LOCATIONS. NO IMPORTED FILL MATERIAL IS PLANNED. 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 35 36 34 33 37 38 39 40 41 EXHIBIT 12 Page 144 of 144 ---PAGE BREAK--- EXHIBIT 13 Page 1 of 4 ---PAGE BREAK--- EXHIBIT 13 Page 2 of 4 ---PAGE BREAK--- W 4 9TH AVE 60% ã ã 10% ã 20% ã 10% U V 397 S OLYMPIA ST W 27TH AVE W 36TH AVE S VANCOUVER ST S CASCADE ST S JEAN ST W 5 1 ST AVE S GARFIELD ST S KENT ST S WASHINGTON ST S HIGHLAND DR E 45TH AVE Sunrise Ridge Preliminary Plat Trip Distribution ¹ Proposed Project Site Date: 2/25/2016 Document Path: \\Kwkfiles\public\Project\JUB\30-16-015 - Sunrise Ridge TIA\GIS\SunriseRidgeTrafficDistMap.mxd EXHIBIT 13 Page 3 of 4 ---PAGE BREAK--- 1 47,766 SF 2 15,826 SF 3 12,772 SF 4 14,239 SF 5 15,457 SF 6 15,318 SF 7 14,409 SF 8 13,961 SF 9 15,090 SF 10 19,025 SF 11 14,452 SF 12 12,028 SF 13 12,000 SF 14 12,000 SF 15 12,000 SF 20 17,620 SF 21 25,420 SF 22 16,487 SF 23 15,741 SF 24 14,831 SF 25 26,323 SF 27 12,068 SF 28 12,018 SF 30 14,816 SF 31 13,491 SF 32 14,813 SF 34 16,297 SF 33 15,076 SF 35 13,944 SF 36 13,965 SF 37 12,126 SF 38 13,520 SF 39 13,619 SF 40 13,440 SF 41 12,856 SF 42 18,435 SF 43 14,552 SF 44 13,763 SF 28.9' L=49 . 8' 366.1' 391.5' L=99.8' L=30.3' 1.5' L = 5 8 .5 ' 157.9' L = 7 8 . 7 ' 120.4' 175.5' 101.1' 100.0' 135.1' 100.0' 149.7' 101.1' L=9 0.2 ' 10.1' 100.0' 156.1' L=13 100.0' 150.0' 86.6' L=62 32.9' 100.0' 147.1' L=95 90.0' 157.2' L=93 90.0' 180.4' 33.6' L = 3 4 .0 ' L=19.9' 61.6' L=2 6. 8' 179.5' 31.4' L= 71 128.9' 131.5' L= 4 9. 8' 35.0' 120.0' 113.2' 100.0' 120.0' 100.0' 100.0' 120.0' 100.0' 100.0' 120.0' 100.0' 57.1' L= 31. 8 ' 125.2' L=8 8.8 ' 116.8' 109.3' L= 88.8' 129.2' 110.4' L=101. 3 ' L=26.7' 53.5' L = 2 8 .0 ' 163.1' 30.0' 171.5' L = 4 3 . 7 ' 198.6' 62.9' 183.4' L = 5 7 . 7' 191.2' L=6.1' 124.1' 132.1' 120.2' 23.9' L=15.0' L = 7 1 .0 ' 168.6' 120.0' L = 9 0 .0 ' 30.0' 153.2' 126.1' 54.1' L = 5 2 .8 ' 23.7' 338.4' 192.8' 54.8' 163.5' 238.0' 62.8' 63.3' 54.9' L = 2 5 .2 ' L=24.6' 87.9' 134.0' 75.4' 134.0' 40.4' L = 9 9 . 7 ' 93.3' L= 17 . 9 ' L=31.6' L=10 1.3' 133.2' L=12 1.5' 35.0' 103.9' 119.2' L=22 14.9' L = 7 5 .5 ' 99.4' 100.0' L= 8 8 .4 ' 87.7' 143.1' 150.1' L=38.6' 91.9' 18.2' L = 81. 4 ' 107.8' 74.0' 102.4' L= 79 L=33.3' L=9.3' 14.3' L=47.2' 50.9' 103.1' 16.4' 49.9' 34.9' 10.0' L=30.0' L= 12 4 .4 ' 8.0' 104.0' 130.0' 104.0' 107.9' 130.0' 93.3' L= 8.2 ' 70.2' 63.6' 130.4' L =7 3 .5 ' 123.4' 122.1' L= 5 9. 9 ' L=27.3' 24.0' L= 91 L= 30 .1 ' 69.3' 46.2' 61.9' 86.1' 208.9' 92.1' 181.2' 236.5' 151.9' 29 12,704 SF 130.6' 21.8' L= 12 4.9 ' 33.8' 4.0' L=47.2' L = 9 9 . 7 ' 82.0' 26 51,946 SF 199.01' R = 7 5 . 0 0 ' R= 15 0 .00' R= 15 0. 00 ' R=31 0.00' R=31 0.0 0' R =1 5 0.0 0 ' R=500 .00' R =1 5 0.0 0' R =2 00 .0 0' R =9 3 .10 ' R=31 0.00 ' 86.00' 15.00' 63.62' 20.00' 400.00' 341.56' 14.94' 205.35' R= 15 0 .00 ' 32.66' 60.08' 332.00' L = 1 3 5 .9 ' 19 12,042 SF 18 11,706 SF 16 12,108 SF 17 15,991 SF 54.0' 119.8' L = 66 . 9 ' 14.9' L= 1.3' 123.2' 125.2' 112.0' 109.3' T. E. R. N. 8 29 24 Sunrise Ridge Subdivision A project in the City of , WA Preliminary plat for: FEB 26, 2016 Date: 0032.00 JF Eng. Job # DJ Sunrise Development LLC 5602 S Newport Pl PR Kennewick, WA 99337-4632 1 A B C D E F G H I J K L JF VICINITY MAP 1"=2,000'± 3 2 5 4 7 6 9 8 11 10 13 12 15 14 16 SUNRISE RIDGE 5220 S. Auburn Pl Kennewick, WA 99337 (509) 551-8174 PHN www.JFEngineering.pro CIVIL ENGINEERING PROJECT MANAGEMENT PLANNING ENGINEERING, PLLC Checked by: JEF Drawn by: JEF PRELIMINARY S T A T E O F W A S H N G T O N J O H N E R I C F E T T E R O L F D E R E T S I G E R 38322 R E E N I G N E L A N O I I S S E F O R P C101 Scale V: N/A Scale H: 1"=80' Know what'sbelow. before you dig. Call R LOCATED IN THE W ½ OF SEC 24, T 8 N, R 29 E OF THE WILLAMETTE MERIDIAN STREET STREET S NEWPORT PL S OLYMPIA ST 0 80 1"=80' 160 40 USBR (KID) S NEWPORT PL 45th AVENUE HWY 397 VANCOUVER STREET OLYMPIA ST SITE OLYMPIA ST. GARFIELD ST. W 53rd AVE W 52nd AVE STATISTICS COMPREHENSIVE PLAN DESIGNATION: LDR LAND USE ZONING DESIGNATION: RS TOTAL PROJECT AREA: nnAc PROPOSED # LOTS: 44 AVERAGE LOT SIZE: nnn SF MIN. LOT SIZE: TO HWY 397 PHASE 2 PHASE 1 PHASE 3 PH 2 PH 3 PROJECT BOUNDARY PHASE 3 PHASE 2 PHASE 1 EXISTING STRUCTURE, TYPICAL EXISTING STRUCTURE, TYPICAL S OLYMPIA ST PROPOSED NEW PUBLIC STREET INTERSECTION EXISTING STREET INTERSECTION TEMPORARY TURN-ROUND CONSTRUCTED WITH PHASE 1, REMOVED WITH PHASE 2 EXHIBIT 13 Page 4 of 4