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7041 Koll Center Parkway, Suite 110 Pleasanton, CA Phone [PHONE REDACTED] Fax [PHONE REDACTED] e-mail: [EMAIL REDACTED] TECHNICAL MEMORANDUM DATE: March 30, 2010 Project No.: 418-02-07-22.05 TO: Jack Bond, City of Modesto, Project Manager FROM: Charles Duncan, Project Manager SUBJECT: City of Modesto’s 2010 Water System Engineer’s Report Evaluation of the Existing and Buildout Water System for the Waterford Outlying Service Area (Waterford TM) In the mid 1990’s the City of Modesto (City) acquired the former Del Este Water System, which included the communities of Grayson, City of Waterford, Hickman, Del Rio, and a portion of the City of Turlock. The City now manages, operates and maintains these five outlying water service areas as independent satellite systems. As a component of the City's Water System Hydraulic Model Update Project, the City has requested West Yost Associates (WYA) to provide an individual hydraulic assessment of each of these separate systems in order to evaluate the ability of existing facilities to meet current and buildout demands. The hydraulic evaluation of the City of Waterford (Waterford) Water System is addressed in this Technical Memorandum (TM). 1.0 SUMMARY The hydraulic assessment included three system components and the ability to serve current and buildout demands: groundwater pumping capacity; storage capacity; and distribution system needs. 1.1 Groundwater Pumping Capacity The system assessment evaluated the adequacy of existing production wells to meet current water demands for two conditions: Peak Hour; and Maximum Day plus fire flow conditions. Buildout Peak Hour and Maximum Day demand were calculated as 3,167 gallons per minute (gpm) and 2,564 gpm, respectively. The system was reviewed with all wells producing, and with the largest well out of service reliable pumping capacity). The reliable pumping capacity of 3,170 was sufficient to meet Maximum Day demand conditions and Peak Hour demand conditions. Though the reliable capacity is able to meet demands, it is recommended that a standby generator be installed at four existing wells to improve reliability of service in case of a power outage. ---PAGE BREAK--- Technical Memorandum March 30, 2010 Page 2 West Yost Associates o:\c\418\02-07-22\wp\er\20091031ceJ1AppJ 1.2 Storage Capacity The storage capacity assessment evaluated total storage and peaking capacity requirements based on three criteria: operational storage; fire storage; and emergency storage. Operational storage was estimated to be as 0.25 x Maximum Day demand. Fire flow was estimated to be as 2,500 gpm for a 4-hour duration. Emergency storage was estimated to be as 1.00 x the average day demand. Approximately 0.66 MG of storage and a new 2.0 mgd booster pump station are recommended to meet existing City storage criteria under reliable pump capacity conditions. A new 700 gpm well is required to meet future City storage criteria under reliable pump capacity conditions, as shown on Figure 10. 1.3 Existing Distribution System The City has established a minimum requirement of 40 pounds per square inch (psi) of system pressure to meet Peak Hour demand, and 20 psi of residual pressure, measured at the flowing hydrant, to meet Maximum Day demand plus fire flows. Also, head loss should remain below 7 feet per 1,000 feet (ft/kft) of distribution piping, and velocity should not be greater than 7 feet per second (fps). WYA developed the system hydraulic model using MWH Soft’s H2ONET software. Model inputs included pipelines, junctions, wells, tanks, and pumps. Additional information about the hydraulic model is provided in Attachment A. WYA’s hydraulic modeling of the Waterford water service area indicates that the existing supply system of six operational wells can maintain a minimum system pressure of 40 psi during Peak Hour demand conditions. However, the existing supply cannot meet minimum 20 psi residual pressures during Maximum Day plus fire flow demand conditions. Maximum velocity criteria was met for Peak Hour demand conditions, however maximum head loss conditions were not met. However, since both criteria were not exceeded, system improvements are not recommended for the Peak Hour demand scenario. Maximum velocity and head loss conditions were not met for smaller diameter pipelines in the Maximum Day plus fire flow demand condition. To correct these existing system deficiencies, water system infrastructure to provide additional supply and system reliability for existing users must be constructed. The recommended additional storage and pumping facilities needed to meet the City’s storage criteria address the existing supply deficiencies. In addition, new and upsized pipelines are necessary to rectify current pressure and velocity deficiencies. Recommended capital improvements to the existing Waterford water system are listed below, and anticipated to cost approximately $6.9M, as detailed in Table 11 of this TM. Construct a new 0.66 MG tank and associated 2.0 mgd pump station to ensure adequate storage and supply for the existing system. Install backup generators at well sites 242, 244, 245, and 286. Install 2,980 linear feet of new pipeline and 13,510 linear feet of upsized pipeline. ---PAGE BREAK--- Technical Memorandum March 30, 2010 Page 3 West Yost Associates o:\c\418\02-07-22\wp\er\20091031ceJ1AppJ 1.4 Buildout Distribution System The existing Waterford water system is approximately 90 percent built out. One of the largest new development projects, named River Pointe, has an independent water system, and will not be served by the City of Modesto’s Waterford water system. The City of Waterford is also proposing to annex 1,610 acres of agricultural land that also will not be served by the City of Modesto’s Waterford water system. For the purposes of this Technical Memorandum, buildout of the currently approved/adopted General Plan is anticipated to occur within the next 5 years. Additional remaining infill development is anticipated to increase the Waterford service area average day demands by approximately 0.38 mgd (262 gpm) to a total of 2.26 mgd (1,570 gpm). Using the peaking factors shown in Table 8, Maximum Day demands increase to approximately 4.43 mgd and Peak Hour demands increase to approximately 5.47 mgd. The system improvements that are proposed to meet existing demands also provide sufficient pumping capacity to meet Maximum Day, Peak Hour, and Maximum Day plus fire flow buildout conditions. However, these improvements are not sufficient to address buildout storage needs. A seventh well is required to meet storage criteria at buildout. The following capital improvements are required for buildout of the Waterford system and anticipated to cost approximately $2.0M, as detailed on Table 12 of this TM. For the purposes of this Technical Memorandum, buildout of the currently approved/adopted General Plan is anticipated to occur within the next 5-years, and in addition to the previously recommended existing water system capital improvement projects, the following system improvements will be required to provide reliable service to these new customers. 700 gpm new well 2.0 INTRODUCTION In 2002, the City contracted with WYA to provide engineering services to assist in the conversion, updating, enhancement and calibration of a water system hydraulic model for the Waterford water system. Using the methodology described in Attachment A of this TM, WYA developed a hydraulic network analysis model of the Waterford water distribution system to allow computer simulations of various current and buildout demands and flow conditions. The developed hydraulic model was used to evaluate the following demand conditions: Maximum day; Peak hour; and Maximum day plus fire flow. In order to create a hydraulic network analysis model representative of the Waterford water system, WYA completed the steps listed below: ---PAGE BREAK--- Technical Memorandum March 30, 2010 Page 4 West Yost Associates o:\c\418\02-07-22\wp\er\20091031ceJ1AppJ Used shapefiles exported from the City of Modesto’s Geographical Information System (GIS) and existing hard copy maps to develop the hydraulic model. Verified with City Operations staff that the converted hydraulic model system configuration (pipeline sizes, alignments, connections, and other facility sizes and locations) is representative of the current Waterford water system. Evaluated existing water demands by land use type to ensure proper distribution of demands in the hydraulic model. In accomplishing these tasks WYA worked closely with City Engineering and Operations staff to obtain and review the following: as-built drawings and maps to confirm pipeline sizes, material, age, locations and alignments; land use and available metered data; and buildout development plans. Since the development and calibration of the model in 2002, there have been several improvements and additions to the Waterford water system. The changes include an additional 9,192 linear feet of pipeline and 37 service connections. The demands have been updated based on 2006 production data provided by the City, and the 2007 model has been updated to reflect the changes in the system infrastructure and demands. This TM is organized as follows: Service Area Existing Water System Waterford Hydraulic Model Existing Water Supply System Evaluation & Recommendations Buildout Water Supply System Evaluation & Recommendations Capital Costs of Recommendations 3.0 SERVICE AREA The Waterford water service area is located approximately 13 miles east of the City of Modesto along State Highway 132 (Yosemite Boulevard), as shown on Figure 1. The Waterford water system serves approximately 7,500 residents, and encompasses a service area containing approximately 950 acres. This service area is primarily residential with a small central downtown area, and is considered approximately 90 percent developed. The Waterford water service area was originally provided with water service by the Del Este Water Company. In the mid 1990’s, the City of Modesto acquired the Del Este system and began providing water service to Waterford. The majority of the remaining planned development within the Waterford water system is “in fill,” with the River Pointe Development Project being the largest approved development. This development currently operates as an independent water system, therefore demands from the River Pointe Development project were not included in this analysis. ---PAGE BREAK--- Technical Memorandum March 30, 2010 Page 5 West Yost Associates o:\c\418\02-07-22\wp\er\20091031ceJ1AppJ The City of Waterford is proposing to annex approximately 1,610 acres of agricultural land surrounding the existing city limits as shown in the “Land Use Plan Waterford Vision 2025 General Plan” (Land Use Plan). The Land Use Plan was obtained from the City of Waterford website and is shown in Figure 4. The City of Waterford will provide water and wastewater services for the annexed area. The City of Modesto is responsible only for the service area inside the current City of Waterford’s limits, excluding the River Pointe development. It is estimated that within the next 5 years, the Waterford water service area will be completely built out. 4.0 EXISTING WATER SYSTEM The Waterford water system includes a total of six wells, no storage tanks, and approximately 130,000 linear feet of pipeline. Existing Waterford pipelines vary in size from less than 4-inches, up to 12-inches in diameter. A significant number of the Waterford pipelines were replaced and upsized by the City of Modesto shortly after acquiring this system from the Del Este Water Company. Currently, there are no interconnections with other systems. 4.1 Wells The Waterford water system is solely supplied by groundwater from six existing wells, as shown in Figure 1. Groundwater is disinfected by chlorine addition at each wellhead, and then discharged directly into the distribution system. Wells 244 and 303 receive granulated activated carbon (GAC) treatment at the wellhead to treat dibromochloropropane (DBCP). Well 302 and 303 have standby power, and the remaining wells do not have standby power. The well flow totals indicate that Well 244 was out of service from April 2005 through February 2007 and Well 303 was out of service from October 2003 through April 2005. Both wells came back online after GAC was installed at the wellheads. Well characteristics are summarized in Table 1. Table 1. Well Characteristics(a) History Pump Data Well Construction Details Well No. Address Year Drilled Rated Pump Capacity (at 60 psi), gpm Rated Hp Standby Power Treatment System Casing Diameter (inches) Gravel Packed Depth of Annular Seal Casing Depth Perforated From/To Total Depth 242 12315 Dorsey Street 1945/85 520(c) 40 no no 14,12 No None 17 None 295 244 300 Tim Bell Road 1949 470 40 no GAC 12 No NP(b) 133 None 259 245 13601 Skyline Blvd 1965 507 40 no no 14 No NP 124 None 300 286 546 N. Reinway 1984 825 75 no no 20/16/14 No 56 296 290-292 311 302 200 S. Reinway 1991 800(c) 75 Yes no 24/18 No 68 229 NP 237 303 12401 Bonnie Brae 1991 800(c) 75 Yes GAC 24/18 No 52 271 NP 276 Based on information provided by the City. NP = Not provided Equipped with a variable frequency drive (VFD) motor. ---PAGE BREAK--- Technical Memorandum March 30, 2010 Page 6 West Yost Associates o:\c\418\02-07-22\wp\er\20091031ceJ1AppJ Pump efficiency tests were performed on all wells in 2007. Results of these tests are shown in Table 2. Table 2. Well Pump Tests Well No. Date Tested Motor HP Measured Flow, gpm Static Level, ft(a) Pumping Level, ft(a) Discharge Pressure, psi Water HP 242 10/1/07 40 500 87 92 60 29.12 244 10/4/07 40 450 93 99 62 27.53 245 10/1/07 40 500 104 112 60 31.64 286 10/1/07 75 875 82 90 60 50.51 302 10/1/07 75 850 91 104 60 52.07 303 10/2/07 75 500 87 95 60 29.49 Static and Pumping Levels indicate depth to water measurements from reference point elevations. Table 3 provides a summary of the total groundwater production of each individual well in 2008, and Figure 2 provides a graphical summary of this data. 4.2 Storage There are currently no storage facilities or pumping plants (other than the well pumps) in the Waterford service area. 4.3 Pipelines General knowledge of the Waterford pipeline main locations, and material type was gained through discussion with City Operational staff. A significant number of Waterford service area pipelines were replaced and upsized by the City of Modesto after acquiring this system from the Del Este Water Company in the mid 1990s. Pipelines in the center of the Waterford service area are generally 4-inch and 6-inch steel pipelines. The remainder of the pipelines in the service area are believed to be mostly unlined, steel pipelines that range in size from 4 to 12-inches in diameter. The newer developments, for example in the southwest portion of the City use 8-inch diameter pipelines constructed of polyvinyl chloride (PVC). 5.0 DEVELOPMENT OF THE WATERFORD HYDRAULIC MODEL In 2002, WYA developed a hydraulic model of the Waterford water service area using MWH Soft’s H2ONET hydraulic modeling software. This model has been updated to reflect current demands and infrastructure. A summary of the assumptions, criteria, and model components is included in Attachment A of this TM. ---PAGE BREAK--- Month gallons MG gallons MG gallons MG gallons MG gallons MG gallons MG January 18,672 0.02 6,130,860 6.13 7,011,671 7.01 20,405 0.02 14,270,632 14.27 3,642 0.00 February 22,638 0.02 5,478,398 5.48 1,488,931 1.49 26,692 0.03 15,321,522 15.32 2,165,873 2.17 March 374,107 0.37 5,576,261 5.58 7,060,633 7.06 17,220 0.02 19,119,518 19.12 7,658,095 7.66 April 181,421 0.18 4,944,216 4.94 26,440,242 26.44 25,935 0.03 20,155,630 20.16 8,357,223 8.36 May 225,477 0.23 4,868,422 4.87 34,289,600 34.29 679,658 0.68 22,950,282 22.95 12,741,263 12.74 June 7,961,603 7.96 4,543,360 4.54 33,527,278 33.53 298,761 0.30 23,218,704 23.22 14,046,045 14.05 July 13,681,550 13.68 3,766,342 3.77 34,524,856 34.52 116,112 0.12 23,617,372 23.62 13,345,026 13.35 August 14,454,261 14.45 3,632,305 3.63 34,073,224 34.07 202,332 0.20 23,042,642 23.04 11,382,450 11.38 September 13,756,641 13.76 3,620,252 3.62 22,275,322 22.28 134,867 0.13 21,778,784 21.78 8,336,193 8.34 October 11,769,409 11.77 2,474,628 2.47 8,118,732 8.12 64,007 0.06 21,217,330 21.22 6,086,770 6.09 November 9,291,857 9.29 0 0.00 44,395 0.04 18,480 0.02 17,342,222 17.34 4,982,465 4.98 December 6,134,086 6.13 0 0.00 54,502 0.05 19,618 0.02 17,138,410 17.14 2,190,536 2.19 Subtotal 77,871,722 77.87 45,035,041 45.04 208,909,385 208.91 1,624,087 1.62 239,173,048 239.17 91,295,579 91.30 Total Annual Supply 663.91 Source: Data provided by the City of Modesto on September 4, 2009, from the file well flow totals 2002 to present.xls Table 3. Summary of Waterford Service Area Production in 2008 Well 242 Well 244 Well 245 Well 286 Well 302 Well 303 West Yost Associates o:\c\418\02-07-22\wp\er\20091031ceJ2waterfordproduction2006 Last Revised: 05/20/08 City of Modesto Engineer's Report Appendix J Waterford TM ---PAGE BREAK--- Technical Memorandum March 30, 2010 Page 8 West Yost Associates o:\c\418\02-07-22\wp\er\20091031ceJ1AppJ 6.0 EXISTING WATER SUPPLY SYSTEM EVALUATION AND RECOMMENDATIONS 6.1 Overview This section presents findings from the hydraulic evaluation of the Waterford existing water distribution system and its ability to meet City of Modesto’s recommended water system operational criteria under existing demand conditions. The existing water distribution system was evaluated under the following demand scenarios: Maximum Day Demand Peak Hour Demand Maximum Day Demand Plus Fire Flow 6.2 Existing System Potable Water Demands Average day potable water demands for the existing Waterford system were estimated and allocated based on the methodology described in Attachment A. Based on production data provided by the City of Modesto from 2003 through 2007, Table 4 shows the peaking factors used to estimate Maximum Day and Peak Hour demands. The Maximum Day peaking factor was developed based on a 5-year average from 2002 through 2007. The Peak Hour peaking factor was developed based on a 2-year average from 2006 through 2007. Table 4. Existing System Water Demand and Peaking Factors 2006 Demands Demand Condition Peaking Factor(a) mgd gpm Average Day 1.88 1,309 Maximum Day 1.96 x Average Day 3.69 2,564 Peak Hour 2.42 x Average Day 4.56 3,167 Based on available water production data for the Waterford service area. 6.3 Existing System Groundwater Pumping Capacity Evaluation The Waterford service area is supplied exclusively by groundwater that is pumped from six existing production wells. Table 5 provides a summary of recent pump flow testing for each operational well, and indicates a total existing supply capacity of 4,020 gpm. For water supply planning purposes, the City has defined Reliable Pumping Capacity as the system’s groundwater pumping capacity assuming the largest well is out of service. This scenario provides an allowance for mechanical breakdowns, maintenance, or other operational issues. ---PAGE BREAK--- Technical Memorandum March 30, 2010 Page 9 West Yost Associates o:\c\418\02-07-22\wp\er\20091031ceJ1AppJ As shown on Table 5, the current total Reliable Pumping Capacity of 3,170 gpm is sufficient to meet existing Peak Hour demands of 3,167 gpm. Though the system does not have a Reliable Pumping Capacity deficiency under Maximum Day and Peak Hour demand conditions, it is recommended that stand by generators be installed at all wells to improve reliability of service in case of a power outage. Table 5. Summary of Existing System’s Supply Facilities Well Pump Name Efficiency, percent Standby Power Existing Capacity, gpm(a) Existing Maximum Day Demand, gpm Existing Peak Hour, gpm 242 65 No 450 244 68 No 475 245 67 No 795 286 63 No 850 302 69 Yes 850 303 48(b) Yes 600 Total Capacity 4,020 2,564 3,167 Total Reliable Capacity 3,170 Adequate Adequate Based on pump flow testing from September 2007. Pump tests conducted by City operations staff. Based on the low efficiency, WYA recommends that the City conduct additional tests for Well 303. 6.4 Existing System Storage Capacity Evaluation Criteria was defined by WYA for the City in 2003 for determining treated water storage and system peaking capacity needs to meet diurnal operational peaks, fire flows, and emergency conditions. Total storage and system peaking capacity requirements can be evaluated based on the following three components: Operational Storage: 25 percent of Maximum Day demand; Fire Storage: The required fire flow times the fire flow duration period, as required by the City’s Fire Marshall; and Emergency Storage: 1 x average day demand. The Waterford system currently does not have any tanks or storage reservoirs; therefore, all of its available storage capacity and ability to meet peak operational demands is based on groundwater basin storage and pumping capacity. This dependence on the groundwater basin for storage presents a storage reliability issue. There is no allowance for possible contamination or other scenario that renders a portion of the basin unavailable. Wells 244 and 303 currently require well head treatment facilities to remove dibromochloropropane. In the future, lowering of the arsenic standard and other emerging water quality issues may further impact the reliability of the groundwater basin. ---PAGE BREAK--- Technical Memorandum March 30, 2010 Page 10 West Yost Associates o:\c\418\02-07-22\wp\er\20091031ceJ1AppJ As shown on Table 6 below, approximately 0.66 MG of tank storage is required in the existing Waterford water system to meet existing City of Modesto storage criteria. This volume was calculated using a Reliable Pumping Capacity scenario with either Well 286 or Well 302 out of service. In addition, a 2.0 mgd booster pump station is required in conjunction with the tank to provide needed pumping capacity. Table 6. Summary of Required Above Ground Storage for Existing System Storage Component Component Detail Storage, MG Operational 0.25 x max day demand 0.92 Fire 2,500 gpm for 4 hours 0.60 Emergency (see Table 7) 1 x average day demand 1.88 Subtotal 3.40 Groundwater Credit(a) 60% reliable production capacity (2.74) Total Storage Required 0.66 Sixty percent of existing reliable groundwater pumping capacity (without Well 286 or 302). 6.5 Existing Distribution System Evaluation The hydraulic model identified areas of the Waterford existing system in which minimum pressure could not be maintained, or where velocities and/or head losses were found to exceed City of Modesto design standards. Detailed discussion is provided in the following sections. 6.5.1 Peak Hour Demand Conditions The Peak Hour demands for the City’s potable water distribution system under existing conditions are approximately 4.56 mgd (3,167 gpm). This Peak Hour demand condition was simulated in the model. Results indicated that the existing distribution system could reliably deliver these demands under the City’s minimum pressure criteria of 40 psi (see Figure This analysis also indicated that head losses in existing pipelines exceed the City’s criteria of < 7 ft/kft, but were able to meet the velocity criteria of < 7 fps. Since flow did not exceed both head loss and velocity criteria, existing pipelines were not recommended to be rehabilitated or upsized to meet Peak Hour demand conditions. 6.5.2 Maximum Day Plus Fire Flow Demand Conditions Fire flows are to be met concurrently with a Maximum Day demand condition, while maintaining a minimum residual system pressure of 20 psi, as measured at the flowing hydrant. The fire flow demand varies based on land use (see Figure as shown in Table 7. Based on an analysis of the Maximum Day plus fire flow demand condition, Waterford’s existing water system cannot maintain a minimum residual system pressure of 20 psi in the northern areas of the Waterford service area (see Figure In addition, numerous pipelines within the older portions of the Waterford system exceeded the maximum head loss and velocity criteria, as these areas are typically served with smaller diameter pipelines. Upsizing of 13,510 linear feet of 2 to ---PAGE BREAK--- Technical Memorandum March 30, 2010 Page 11 West Yost Associates o:\c\418\02-07-22\wp\er\20091031ceJ1AppJ 4-inch diameter pipeline to 8-inch diameter pipeline is required to ensure minimum system pressures in the event of a fire, or to mitigate high head losses and velocities during high demands. The pipelines that did not meet the maximum head loss and velocity criteria and require upsizing are shown in Figure 6. Table 7. Fire Flow Requirements Land Use Symbol Fire Flow Duration Residential Estates RE 1,500 2 hrs Low Density Residential LD 1,500 2 hrs Multi-Family MF 1,500 2 hrs Regional Commercial RC 2,000 3 hrs Commercial CO 2,000 3 hrs Industrial IND 2,500 4 hrs Public / Government PG 2,000 3 hrs Open Space OS 1,500 2 hrs 6.6 Summary of Recommended Existing Water System Improvements Based on the analyses completed for the Waterford water system, there is a need for specific water facility improvements throughout Waterford’s service area. An overview of the recommended facilities is provided in Figure 6. The locations of the proposed facilities are for planning purposes only and should be developed further in future predesign studies. A summary of the recommended improvements is provided below. Construct a new 0.66 MG tank and associated 2.0 mgd pump station to ensure adequate storage and supply for the existing system. Install standby generators at existing wells to provide reliable service in the event of a power outage. Install 2,980 linear feet of new pipeline and 13,510 linear feet of upsized pipeline. Localized pipeline improvements are also needed to rectify current pressure and flow deficiencies. These improvements are shown in Figure 6. With the completion of these recommendations, the residual pressure under fire flow concurrent with Maximum Day demand conditions meets the 20 psi requirement (see Figure 7.0 BUILDOUT WATER SUPPLY SYSTEM EVALUATION & RECOMMENDATIONS 7.1 Overview This section presents the hydraulic evaluation of the Waterford buildout water distribution system and its ability to meet City of Modesto’s recommended water system operational criteria ---PAGE BREAK--- Technical Memorandum March 30, 2010 Page 12 West Yost Associates o:\c\418\02-07-22\wp\er\20091031ceJ1AppJ under buildout demand conditions. The existing water distribution system was evaluated under Maximum Day, Peak Hour and Maximum Day with fire flow demand conditions. 7.2 Buildout System Potable Water Demands Although the Waterford water service area is approximately 90 percent built out, there will be additional water demands on the system over the next five years as buildout of the existing general plan area is completed. Figure 8 shows the location of proposed new water service areas. It should be noted that the planned River Pointe Development has an independent water system, and will not be served by the City of Modesto. Therefore, water demands for the River Pointe Project are not included in this analysis of future water needs or infrastructure. The City of Waterford is proposing to annex approximately 1,610 acres of agricultural land surrounding the existing city limits as shown in the “Land Use Plan Waterford Vision 2025 General Plan” (Land Use Plan) in Figure 4, obtained from the City of Waterford website. The City of Waterford will provide water and wastewater services for the annexed area. Of this area, the City of Modesto is only responsible for the service area inside the current City of Waterford’s limits, excluding the River Pointe Development. Based on data provided to WYA by the City, potable water demands are estimated to increase by approximately 0.38 mgd, for a total of 2.26 mgd under average day demand conditions. Using peaking factors of 1.96 and 2.42, the demands for Maximum Day and Peak Hour are 4.43 mgd and 5.47 mgd respectively (see Table In order to assess required facilities in addition to the existing system CIP recommendations, these buildout demands were added to the model. The same analyses and calculations that were conducted to evaluate the ability of the system to meet current demands were applied for the analysis of buildout conditions. The findings are discussed below. Table 8. Buildout Waterford Water Demand Buildout Demands Demand Condition Peaking Factor(a) mgd gpm Average Day 2.26 1,570 Maximum Day 1.96 x Average Day 4.43 3,077 Peak Hour 2.42 x Average Day 5.47 3,800 Based on available water production data for the Waterford service area. 7.3 Buildout System Pumping Capacity Evaluation As discussed above, the Waterford water service area will have 6 operational wells, as shown in Figure 7. Table 9 provides a summary of recent pump flow testing for each operational well, and indicates a total existing supply capacity of 5,250 gpm and a total Reliable Pumping Capacity of 4,400 gpm. These totals include the Tank Pump Station recommended as part of the existing ---PAGE BREAK--- Technical Memorandum March 30, 2010 Page 13 West Yost Associates o:\c\418\02-07-22\wp\er\20091031ceJ1AppJ system improvements. The total Reliable Pumping Capacity is sufficient to meet buildout Maximum Day demand of 3,077 gpm. 7.4 Buildout System Storage Capacity Evaluation The same criteria that was defined for determining existing treated water storage and system peaking capacity needs to meet diurnal operational peaks, fire flows, and emergency conditions were applied to buildout conditions. The buildout Waterford system requires a total of 0.57 MG of additional storage, as shown in Table 10, to meet buildout City of Modesto storage criteria with the completion of the Existing CIP Improvement facilities. This added storage can be obtained by constructing a seventh 700 gpm well and backup generator. Table 9. Summary of Buildout System’s Supply Facilities Pump Name Efficiency, percent Standby Power Buildout Capacity, gpm(a) Buildout Maximum Day Demand, gpm Buildout Peak Hour Demand, gpm 242 65 No 450 244 68 No 475 245 67 No 795 286 63 No 850 302 69 Yes 850 303 48 Yes 600 New Tank 75 Yes 1,230(b) Total Pumping Capacity 5,250 3,077 3,800 Total Reliable Pumping Capacity(c) 4,400 3,077 3,800 Based on pump flow testing from September 2007. Pump tests conducted by City operations staff. Based on new tank pump having a pumping capacity of 1,230 gpm. Reliable Pumping Capacity is defined as the total pumping capacity of the system with the largest well out of service. Table 10. Summary of Required Above Ground Storage at Buildout Storage Component Component Detail Storage without New Well, MG Storage with New Well, MG Operational 0.25 x max day demand 1.11 1.11 Fire Storage Component 2,500 gpm x 4 hours 0.60 0.60 Emergency Storage Component 1 x average day demand 2.26 2.26 Subtotal 3.97 3.97 Constructed Storage Tank (0.66) (0.66) Groundwater Credit 60% reliable production capacity (2.74) (3.34)(a) Total Storage Required 0.57 0.00 Sixty percent of buildout reliable groundwater pumping capacity (includes New Well). ---PAGE BREAK--- Technical Memorandum March 30, 2010 Page 14 West Yost Associates o:\c\418\02-07-22\wp\er\20091031ceJ1AppJ 7.5 Buildout Distribution System Evaluation Analyses were conducted to identify areas of the Waterford buildout system in which design pressures could not be maintained, or where velocities and/or head losses were found to exceed City of Modesto design standards. Detailed discussion is provided in the following sections. 7.5.1 Maximum Day Demand Conditions The Maximum Day demands for the City’s potable water distribution system under buildout conditions are approximately equal to 4.43 mgd (3,077 gpm), respectively. This high demand condition was simulated in the model and the results indicated that the distribution system, including pipeline improvements identified above for the existing system, will adequately deliver these demands under the City’s minimum pressure criteria of 40 psi. This analysis also indicated that head losses in existing pipelines exceed the City’s criteria of < 7 feet per 1,000 feet (ft/kft); however, flows were able to meet the velocity criteria of < 7 feet per second (fps). The pipelines that did not exceed both head loss and velocity criteria are not recommended to be rehabilitated or upsized. 7.5.2 Peak Hour Demand Conditions The Peak Hour demands for the City’s potable water distribution system under buildout conditions are approximately equal to 5.47 mgd (3,800 gpm), respectively. This high demand condition was simulated in the model and the results indicated that the buildout distribution system could adequately deliver these demands under the City’s minimum pressure criteria of 40 psi (see Figure This analysis also indicated that head losses in existing pipelines exceed the City’s criteria of < 7 feet per 1,000 feet (ft/kft); however, flows were able to meet the velocity criteria of < 7 feet per second (fps). The pipelines that did not exceed both head loss and velocity criteria are not recommended to be rehabilitated or upsized. 7.5.3 Maximum Day plus Fire Flow Demand Conditions Applying the fire flow requirements mentioned above, hydrants were capable of maintaining the required 20 psi residual pressure under fire flow conditions concurrent with the future buildout Maximum Day demand condition. 7.6 Summary of Recommended Buildout System Improvements Based on the analyses detailed above, WYA recommends that a new 700 gpm well be constructed to provide additional storage supply, as illustrated on Figure 10. The locations of the proposed facilities are for planning purposes only and should be developed further in future predesign studies. ---PAGE BREAK--- Technical Memorandum March 30, 2010 Page 15 West Yost Associates o:\c\418\02-07-22\wp\er\20091031ceJ1AppJ 8.0 CAPITAL COSTS OF RECOMMENDED IMPROVEMENTS The estimated probable capital costs for the recommended water system improvements to serve the Waterford existing and buildout conditions are presented in Tables 11 and 12, respectively. The capital costs are presented in March 2010 dollars at an Engineering News Record (ENR) construction cost index (CCI) of 9728.17 consistent with San Francisco. The costs include an estimate of 50 percent on the estimated construction cost to account for administration, design, and engineering costs and other contingencies. The costs for the facilities do not include costs for annual operation and maintenance, or costs for acquisition of rights-of-way. ---PAGE BREAK--- CIP CIP Unit Cost Cost ID Reason Item Unit Quantity Pipelines FF01 Fire Flow Along Bentley Street from Tim Bell Road to Harriett Drive 8-inch lf 1,260 101 127,000 FF01 Fire Flow Along Peel Lane from Bentley Street to dead end 8-inch lf 460 101 46,000 FF02 Fire Flow Along alley between D Street and E Street from Bentley Street to Welch Street 8-inch lf 530 101 53,000 FF02 Fire Flow Along Welch Street from alley north of E Street to alley south of Covey Street 8-inch lf 420 101 42,000 FF02 Fire Flow Along alley south of Covey Street from Welch Street to Covey Street bend 8-inch lf 310 101 31,000 FF02 Fire Flow Along Covey Street from alley to Tim Bell Road 8-inch lf 410 101 42,000 FF03 Fire Flow Along Center Street from Yosemite Boulevard to Terrace Court 8-inch lf 570 101 58,000 FF03 Fire Flow Along Terrace Court from Center Street to dead end 8-inch lf 330 101 33,000 FF04 Fire Flow Along C Street from Oden Drive to La Gallina Avenue 8-inch lf 330 101 33,000 FF04 Fire Flow Along alley between C Street and D Street from La Gallina Avenue to Main Street 8-inch lf 1,070 101 107,000 FF05 Fire Flow Along Chaffee Lane from Bentley Street to dead end 8-inch lf 550 101 56,000 FF06 Fire Flow Along alley between E Street and F Street from La Gallina Avenue to Yosemite Blvd 8-inch lf 3,200 101 322,000 FF06 Fire Flow Along Welch Street from alley south of G Street to alley south of E Street 8-inch lf 850 101 85,000 FF06 Fire Flow Along south side of Yosemite Boulevard from Hickman Road to N. Appling Road 8-inch lf 2,130 101 214,000 FF07 Fire Flow Along Hickman Street from Baker Street to N. Appling Road 8-inch lf 310 101 31,000 FF07 Fire Flow Along N. Appling Road from Hickman Street to Yosemite Boulevard 8-inch lf 350 101 35,000 FF08 Fire Flow Along Yosemite Boulevard between Reinway Avenue and North Pasadena Avenue 8-inch lf 980 101 98,000 FF09 Fire Flow Along Tim Bell Road just south of Bonnie Brae Avenue and Vineyard Rd 8-inch lf 490 101 49,000 FF10 Fire Flow Along Skyline Blvd and Lyn Way from Bentley Street to Lyn Way 10-inch lf 1,940 123 237,000 Storage Tank Supply 0.66 MG Storage Tank(c) Supply 2.0 MGD Pump Station(d) Well Backup Generators Supply Well 242 ls 1 133,000 133,000 Supply Well 244 ls 1 133,000 133,000 Supply Well 245 ls 1 133,000 133,000 Supply Well 286 ls 1 133,000 133,000 Subtotal (Overall Program) 4,631,000 50% Contingency 2,317,500 Total Estimated Construction Cost for Existing CIP Recommendations 6,948,500 Does not include site specific facilities such as wellhead treatment. Table 11. Recommended CIP Program for Existing Waterford Water System(a) All unit prices presented in SF March 2010 dollars (ENR Construction Index = 9728.17). Unit prices based on combination of cost curves, construction cost guidelines and similar construction projects. Pump Station cost includes backup / standby generators and SCADA. Backup generator cost estimated at $200,000 per installation. Storage Tank and Pump Station size increased from its original capacity of 0.58 MG and 1.74 MGD, respectively, to provide buildout storage and supply capacity. See the Evaluation of Buildout Water Supply System section for a discussion of the Storage Tank changes in size. ls 1 2,400,000 2,400,000 West Yost Associates o:\c\418\02-07-22\wp\er\20091031ceJ3WFTAB11 Last Revised: 09/11/08 City of Modesto Engineer's Report Appendix J Waterford TM ---PAGE BREAK--- CIP CIP Unit Cost Cost ID Reason Item Unit Quantity Wells Supply New Well with 700 gpm pump, backup generator, and SCADA Well 1 1,333,000 1,333,000 Subtotal 1,333,000 50% Contingency 667,000 Total Estimated Construction Cost for Buildout System CIP Program 2,000,000 Does not include site specific facilities. All unit prices presented in SF March 2010 dollars (ENR Construction Index = 9728.17). Unit prices based on combination of cost curves, construction cost guidelines and similar construction projects. A construction contingency (20 percent) is applied to the base construction cost. Other project construction contingency costs (30 percent) are applied to the construction costs after the construction contingency has been applied. Table 12. Recommended CIP Program for Buildout Waterford Water System(a) West Yost Associates o:\c\418\02-07-22\wp\er\20091031ceJ4WFTAB12 Last Revised: 11/17/08 City of Modesto Engineer's Report Appendix J Waterford TM ---PAGE BREAK--- ---PAGE BREAK--- West Yost Associates o:\c\418\02-07-22\wp\er\20091031ceJ2waterfordproduction2006 Last Revised: 11/6/09 City of Modesto Engineer's Report Appendix J Waterford TM Figure 2. City of Waterford - Production by Well (2008) 0 10,000,000 20,000,000 30,000,000 40,000,000 50,000,000 60,000,000 70,000,000 80,000,000 90,000,000 100,000,000 January February March April May June July August September October November December Month Production (Gallons) Well 242 Well 244 Well 245 Well 286 Well 302 Well 303 Notes: - Data based on well production information in Table 3. ---PAGE BREAK--- ---PAGE BREAK--- ---PAGE BREAK--- ---PAGE BREAK--- ---PAGE BREAK--- ---PAGE BREAK--- ---PAGE BREAK--- ---PAGE BREAK--- ---PAGE BREAK--- ATTACHMENT A Development of Waterford’s Hydraulic Model ---PAGE BREAK--- West Yost Associates A-1 o:\c\418\02-07-22\wp\er\20091031ceJ5AttA ATTACHMENT A. DEVELOPMENT OF WATERFORD’S HYDRAULIC MODEL WYA developed a hydraulic model for the City of Modesto (City) of the City of Waterford (Waterford) Service Area using MWH Soft’s H2ONET hydraulic modeling software. The distribution system depicted in the City provided AutoCAD file was replicated as pipe, junctions, wells, tanks, and pumps. In 2009, this model was converted to InfoWater v6.5. Modeling Assumptions and Criteria Establishing computer modeling assumptions and criteria was important for the development of the model, calibrating and running the model, and interpreting the results of the computer runs. The assumptions and criteria that were used to develop Waterford’s water distribution system hydraulic model are described below: A minimum pipe size of 2 inches was modeled. Information on pipe length, diameter, material type and age was extracted from the City’s existing GIS and hard copy maps. Pipe roughness coefficients, values, were assigned based on age and pipe material. Pump station piping configurations, performance curves, and motor size information were acquired from “as-built” plans and interviews with City operational staff. Pipe length accuracy was assumed to be ±25 feet. Ground surface elevations were estimated using available digital topographic maps and surveyed benchmark elevations. Elevations were estimated to the nearest foot where spot elevations were not available. The water demands in the model were expressed in gallons per minute (gpm). Peaking Factors Maximum day and peak hour demand factors were calculated using data provided by the City of Modesto. The maximum day peaking factor was developed based on a 5-year average from 2003 through 2007, as shown in Table 1. The peak hour peaking factor was developed based on a 2- year average from 2006 through 2007, as shown in Table 2. ---PAGE BREAK--- West Yost Associates A-2 o:\c\418\02-07-22\wp\er\20091031ceJ5AttA Table 1. Maximum Day Demand Peaking Factor Year Date Max Day, gpd Average Day, gpd Peaking Factor 2003 07/29/03 3,917,395 1,848,047 2.12 2004 06/27/04 3,495,343 1,925,539 1.82 2005 07/18/05 3,669,140 1,798,749 2.04 2006 07/23/06 3,822,592 1,884,390 2.03 2007 07/04/07 3,517,438 1,960,239 1.79 Average 1.96 Table 2. Peak Hour Demand Peaking Factor Year Date Peak Hour, gpm Average Day, gpm Peaking Factor 2006 07/23/06 3,636 1,309 2.78 2007 07/04/07 2,807 1,361 2.06 Average 2.42 Model Development Node elevations were automatically computed using U.S. Geological Survey Digital Elevation Models (DEM). Pipelines were assigned C-factors based on material types and age as indicated by City Operations staff. C-factors ranged from 135 to 100. The water surface elevation for all wells were modeled as fixed-grade reservoirs, with water surface elevations equal to active water pumping levels as reported in City pump tests. Well pumps modeled with design point curves, with the exception of Wells 302 and 303, as presented in Table 3. Flow and head data points are based on observed flow and computed total dynamic head from City pump tests. Pumps at Wells 302 and 303 were modeling using pump curves provided by the City, which were adjusted using pump affinity laws to match field test data. The model includes the original manufacturer’s curves, and a speed setting that matches the operational point from pump test data. Wells 242, 302 and 303 have variable frequency drives to control system pressure. Pumps are modeled with pressure reducing valves (PRV’s), with PRV settings based on control settings provided by the City. ---PAGE BREAK--- West Yost Associates A-3 o:\c\418\02-07-22\wp\er\20091031ceJ5AttA Table 3. Well Model Characteristics Modeled with Design Point Curve Well Diameter, in Head, ft Flow, gpm 242 6 231 500 244 6 242 450 245 6 251 500 286 8 229 875 302(a) 8 243 850 303 8 234 500 Flow and head as indicated from pump test data provided by City of Modesto. Pump modeled with manufacturer’s curve and speed setting of 0.93 to match test flow and head. Flow and head as indicated from pump test data provided by the City of Modesto. Pump modeled with manufacture’s curve and speed setting of 0.84 to match test flow and head. Demand Allocation MWH Soft H2ONet and InfoWater allow the definition of multiple demand fields at a single node to represent different use classes or demand types. For the Waterford model, all existing system demands are assigned in demand field 1. Incremental future demands at buildout are assigned in demand field 2. Existing System Demands Metered Customers: While the Waterford Service Area had four large metered customers and the metered customers accounted for 4 percent of the water demand, these demands did not vary significantly from the average allocated demand per node. Therefore, metered consumption was combined and allocated with the residential unmetered component, and the large metered customer loads were not assigned individually to the closest model node. Unaccounted-for-Water: The City has estimated that Unaccounted-For-Water is approximately 15% of the total production system-wide. Unaccounted-For-Water was assumed to be uniformly lost throughout the distribution system, and therefore was combined for allocation purposes with the residential unmetered component. Unmetered Residential Customers: The remaining demand is by unmetered residential customers. Because the Waterford Service Area is almost fully developed, parcels were assigned equal demand. The unit demand per parcel is the total consumption (1,112 gpm for average day) divided by number of parcels (2,056), or 0.54 gpm per parcel. Parcels, and their associated 0.54 gpm demand, were aggregated to the nearest model junction nodes to develop the base Average Day demand set. Maximum Day and Peak Hour (see Table 4 for factors) demand sets were calculated by applying the appropriate factors to the average day demands. Fire: The Waterford Service Area has a total of 10 different land uses, as depicted in Figure 7. Fire demands for analysis were determined based on land use using the amounts listed in Table 7 in the body of the TM. ---PAGE BREAK--- West Yost Associates A-4 o:\c\418\02-07-22\wp\er\20091031ceJ5AttA Future System Demands Future demands were estimated based on land use information provided by the City of Modesto, as documented in the body of the Waterford System TM. Figure 8 of the TM shows future development areas. Demands were allocated to the model by equally distributing the total estimated demand for new developments to the nodes within the development areas. Scenarios The scenarios modeled are shown in Table 4. Table 4. Model Scenarios Scenario Description Definition EX_AD 2006 Average Day Scenario Model of 2006 average day demand condition EX_MD 2006 Maximum Day Scenario Model of 2006 maximum day demand condition EX_MDFF 2006 Maximum Day plus Fire Flow Scenario Model of the 2006 maximum day demand plus fire flow based on land use condition EX_PH 2006 Peak Hour Scenario Model of 2006 peak hour demand condition EX_CIP Recommended Existing CIP Scenario Model of 2006 fire flow runs with recommended improvements to meet the minimum design criteria FUT_AD Future Average Day Scenario Model of future average day demand condition FUT_MD Future Maximum Day Scenario Model of future maximum day demand condition FUT_MDFF Future Maximum Day plus Fire Flow Scenario Model of future maximum day demand plus fire flow based on land use condition FUT_PH Future Peak Hour Scenario Model of future peak hour demand condition FUT_CIP Recommended Future CIP Scenario Model of future fire flow runs with recommended improvements to meet the minimum design criteria The MWH Soft’s InfoWater model file included with this TM contains these scenarios. Data Sets The Data Sets contained in the model are shown in Tables 5 through 8. ---PAGE BREAK--- West Yost Associates A-5 o:\c\418\02-07-22\wp\er\20091031ceJ5AttA Table 5. Demand Sets Demand Set Description Definition EX_AD 2006 Average Day Demand Set 2006 average day demand (1.88 mgd) EX_MD 2006 Maximum Day Demand Set 2006 maximum day demand (3.69 mgd) EX_MDFF 2006 Maximum Day with Fire Flow Demand Set 2006 maximum day demand with fire flow based on land use EX_PH 2006 Peak Hour Demand Set 2006 peak hour demand condition (4.56 mgd) FUT_AD Future Average Day Demand Set Future average day demand (2.26 mgd) FUT_MD Future Maximum Day Demand Set Future maximum day demand (4.43 mgd) FUT_MDFF Future Maximum Day with Fire Flow Demand Set Future maximum day demand with fire flow based on land use FUT_PH Future Peak Hour Demand Set Future peak hour demand (5.47 mgd) Table 6. Pipe Sets Pipe Set Description Definition EX_SYS Existing System Infrastructure Existing system configuration FUT_SYS Future System Infrastructure Future system configuration EX_CIP Recommended Existing CIP Infrastructure Recommended existing system configuration FUT_CIP Recommended Future CIP Infrastructure Recommended future system configuration Table 7. Fire Flow Sets Fire Flow Set Description Definition FF_ALL Fire Flow at Hydrant Nodes This sets up the fire flow analysis at each hydrant location according to land use ---PAGE BREAK--- West Yost Associates A-6 o:\c\418\02-07-22\wp\er\20091031ceJ5AttA Table 8. Control Sets Control Set Description Definition EX_AD 2006 Average Day Controls Existing average day demand controls EX_MD 2006 Maximum Day Controls Existing maximum day demand controls EX_MDFF 2006 Maximum Day plus Fire Flow Controls Existing maximum day demand with concurrent fire flow demand controls EX_PH 2006 Peak Hour Controls Existing peak hour demand controls EX_CIP Existing CIP Controls Existing system CIP recommended controls FUT_AD Future Average Day Controls Future average day demand controls FUT_MD Future Maximum Day Controls Future maximum day demand controls FUT_MDFF Future Maximum Day plus Fire Flow Controls Future maximum day demand with concurrent fire flow demand controls FUT_PH Future Peak Hour Controls Future peak hour demand controls FUT_CIP Future CIP Controls Future system CIP recommended controls Verification No field verification of the model has been conducted. WYA recommends flow testing and model calibration be performed by the City. Model Element Information To provide flexibility in modeling various system configurations, each modeling element was assigned a Phase, as listed in Table 9 below. Each Phase number corresponds to the modeling elements system configuration. Table 9. Modeling Element Phase Numbering Convention Phase Configuration 1 Existing System 2 Existing System CIP