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7041 Koll Center Parkway, Suite 110 Pleasanton, CA 94566 Phone [PHONE REDACTED] Fax [PHONE REDACTED] e-mail: [EMAIL REDACTED] TECHNICAL MEMORANDUM DATE: October 5, 2009 Project No: 418-02-07-22 TO: Jack Bond, City of Modesto CC: Rich Ulm, City of Modesto Jim Alves, City of Modesto Glenn Prasad, City of Modesto FROM: Charles Duncan, Project Manager Polly Boissevain SUBJECT: City of Modesto’s 2010 Water System Engineer’s Report Facilities Inventory of the Existing Water System for the Contiguous Service Area (Facilities Inventory TM) 1.0 INTRODUCTION From a hydraulic modeling perspective, the City of Modesto (City) provides domestic water to two distinct customer location categories; the contiguous service area, and outlying service areas. The City’s contiguous service area is primarily defined by the current Sphere of Influence (SOI), Salida, North Ceres, and some unincorporated Stanislaus County “islands” within and adjacent to the SOI (Empire is within the SOI). The outlying service areas include Del Rio, Ceres (Walnut Manor), Grayson, Waterford, Hickman, and portions of Turlock. This technical memorandum (TM) describes the existing contiguous service area water system, including its supply, storage, and pipeline facilities (Figure The outlying service area’s water systems are discussed in separate TM’s. 2.0 BACKGROUND In the early 1990’s, the City, Modesto Irrigation District (MID), and the former Del Este Water Company (DEW Co) formed the Modesto Domestic Water Partnership to use a portion of MID’s surface water rights for municipal uses, and entered into a Treatment and Delivery Agreement (TDA) to cover the design, construction, commercial operation, and financing for the Initial Phase of the Modesto Regional Water Treatment Plant This new treatment plant, along with associated storage and delivery facilities, became operational in 1995. Only the commercial operation portion of that TDA is currently active. In 1995, the City acquired the DEW Co, which, as a result, became the primary domestic water purveyor in Stanislaus County. ---PAGE BREAK--- Technical Memorandum October 5, 2009 Page 2 West Yost Associates o:\c\418\02-07-22\wp\ER\20091031ceA1AppA The currently treats water from the Modesto Reservoir and conveys it to the City’s service area to combine with groundwater sources to meet the City’s water supply needs for those municipal customers within the City limits north of the Tuolumne River (southern boundary of MID’s service area), including the communities of Salida and Empire. The Initial Phase of the significantly reduced the City’s reliance on groundwater pumping and also eliminated the groundwater overdraft condition. For a number of years, the City and MID have been working together on the Phase Two Expansion, which is currently under construction, so as to provide the City’s existing customers with a reliable water source and keep pace with the projected growth. 3.0 WATER SUPPLY 3.1 Surface Water Supply Since 1995, the City has received 33,601 acre-feet per year (af/yr) [30 million gallons per day (mgd)], of treated surface water from the The City will be receiving an additional 33,601 af/yr (for a total of 60 mgd) after the expected early 2010 completion of the Phase Two Expansion project. The 60 mgd capacity is an annual average, and both the original and expanded facilities will have peaking capacities greater than the annual averages. The original phase of the has a functional capacity of 42.5 mgd (permitted by the State to produce up to 45 mgd for the last few years), which helps meet the Maximum Day and Peak Hour demands of North Modesto (peaking capacity for the Phase Two Expansion will be determined after start-up operations and testing protocols are completed). Delivery of this surface water supply is made possible via the Amended and Restated Water Treatment and Delivery Agreement (AR TDA) between the MID and the City, dated October 2005. The AR TDA is the document obligating and controlling the delivery of treated surface water by MID to the City. To accommodate the additional flow from the Phase Two Expansion and maximize its hydraulic benefits, the City has been moving forward with design activities required to construct numerous City-Side Improvements (Figure As required by the California Environmental Quality Act, the City has evaluated a number of potential sites for each of the three recommended tanks, and has identified preferred sites for each tank location. The West Tank is under construction, the North Tank is being designed, and the property for the Industrial Tank has recently been purchased. These locations are indicated in Figure 2, and will be used in future hydraulic analyses. The City-Side Improvements also include the construction of automatic control valves (with flow metering capabilities) at existing and future MID turnouts, and new City transmission mains along the Virginia Corridor, Orangeburg Avenue, and Yosemite Boulevard. These recommendations were made based on hydraulic analyses by WYA, and are also shown in Figure 2. For purposes of this TM, it will be assumed that the proposed City-Side Improvements and the Phase Two Expansion project are planned but not yet part of the existing system, since only limited portions have been constructed at the time of this report. ---PAGE BREAK--- Technical Memorandum October 5, 2009 Page 3 West Yost Associates o:\c\418\02-07-22\wp\ER\20091031ceA1AppA 3.2 Groundwater Supply The City has 102 operational wells in the contiguous service area. An operational well is defined as any well that has not been formally abandoned. Of these 102 wells, 78 are currently in production (as per the City’s “Wells Out of Service Report” for August 2009, shown in the 2010 Engineer’s Report, Attachment These 78 wells supplement the treated surface water from the and are shown on Figure 1 and described in Table 1. The total groundwater pumping capacity was calculated by summing the pumping capacity of the 78 production wells in service. From this calculation, the total pumping capacity of the production wells in the contiguous service area was determined to be approximately 118 mgd. This total groundwater pumping capacity includes wells that feed directly into the City’s storage tanks and does not include wells that are out of service (longer than temporary) for water quality or mechanical reasons. 4.0 STORAGE TANKS, BOOSTER PUMP STATIONS, AND PIPELINES 4.1 Storage Tanks The existing contiguous service area contains eight at-grade storage tanks. Six are owned and operated by the City and two are owned and operated by MID. Each is equipped with a booster pump station (MID’s tanks are served by one pump station), as shown on Figure 1 and described in Table 2. Storage Tanks 1 and 2 are not operational, and are scheduled to be removed. Recently, the 750,000 gallon Galas Subdivision Tank was completed, increasing the total storage capacity of the contiguous service area to 18.15 million gallons (MG), however, this tank is not yet operational. Table 2. Existing Contiguous Service Area Storage Characteristics Reservoir Tank Capacity, MG Service Area Diameter, feet Base Elevation, feet Overflow Elevation, feet Tank 3 1.3 Contiguous 95 73(a) 24.5 Tank 4 1.3 Contiguous 95 105(a) 24.5 Tank 5 1.3 Contiguous 95 102(a) 24.5 Tank 6 2.0 Contiguous 116 75(a) 24.5 Tank 7 0.5 Contiguous 50 80(a) 33.5 Tank 8 1.0 Contiguous 82 91(a) 24.5 Tank 10 (Galas) 0.7 Contiguous 60(b) 80.50(b) 33.1(b) Reservoirs 10.0 (two at 5.0 each) Contiguous 146 113 39.5 Total Capacity 18.1 Note: City Tanks 1 and 2 are abandoned. Tank base elevations based on TopoDepot software allocation in model. Information based on as-built plans provided by the City. ---PAGE BREAK--- Pump Available Capacity(a) Capacity(b) [ft] [gpm] [gpm] 1 Modesto 1954 118 no 950 950 75 2 Modesto OOS 1976 255 no 1,500 150 OOS(c) [Uranium] 3 Modesto OOS 1956 138 yes 650 100 OOS(c) [PCE] 4 Modesto 1933 225 no 950 950 100 6 Modesto 1921 234 no 950 950 75 Y 7 Modesto 1922 260 no 950 950 75 8 Modesto OOS 1964 220 no 775 50 OOS(c) [Uranium] 10 Modesto 1939 110 no 400 400 60 14 Modesto OOS 1948 263 no 1,500 100 Y OOS(c) [Uranium] 16 Modesto 1976 312 no 1,800 1,800 150 17 Modesto 1954 232 no 1,450 1,450 100 18 Modesto OOS 1956 250 no 750 100 OOS(c) [Nitrates] 19 South Modesto OOS 1986 240 no 600 unknown OOS(c) [Uranium] 21 Modesto OOS 1959 320 no 1,500 125 OOS(c) [Uranium] 22 Modesto OOS 1960 280 no 1,000 125 OOS(c) [Uranium] 24 Modesto OOS 1961 300 no 1,500 150 OOS(c) [Uranium] 25 Modesto 1962 395 no 1,500 1,500 125 Y 29 South Modesto 1964 144 no 1,058 1,058 75 30 South Modesto 1964 123 no 1,000 1,000 75 32 Modesto OOS 1948 216 yes 800 60 OOS(c) [Nitrates] 33 Modesto 1966 380 no 1,800 1,800 150 Y 34 Modesto OOS 1967 112 no 1,250 100 OOS(c) [Uranium] 36 Modesto 1968 158 no 1,050 1,050 100 37 Modesto OOS 1970 228 no 1,250 125 OOS(c) [Gross Alpha] 38 South Modesto 1971 252 no 1,163 1,163 100 39 Modesto 1972 292 no 1,950 1,950 150 Y 40 Modesto 1974 275 no 1,400 1,400 150 Y 41 Modesto 1976 248 no 1,200 1,200 150 Y 42 Modesto 1976 430 no 1,800 1,800 150 Y 43 Modesto 1977 321 no 1,900 1,900 150 Y 44 Modesto OOS 1980 220 no 1,250 100 Y OOS(c) [Uranium] 45 Modesto 1985 292 no 1,500 1,500 125 46 Modesto 1985 329 no 1,150 1,150 75 47 Modesto 1985 280 no 1,600 1,600 150 48 Modesto 1990 500 yes 1,330 1,330 150 49 South Modesto OOS 1984 266 no 500 75 Y OOS(c) [Arsenic] 50 Modesto 2000 295 yes 800 800 100 51 Modesto 1990 470 yes 2,200 2,200 250 52 Modesto 1992 280 yes 1,600 1,600 150 Y 53 Modesto OOS 1992 255 yes 1,500 100 OOS(c) [Nitrates] 54 Modesto 1993 472 yes 2,400 2,400 200 Share with Tank 4 55 South Modesto OOS 1993 265 yes 1,500 100 OOS(c) [Uranium] 56 Modesto 1964 250 yes 650 650 75 57 Modesto 1994 200 yes 1,350 1,350 100 Y 58 Modesto 1994 500 yes 1,300 1,300 100 59 Modesto 1995 265 yes 1,400 1,400 125 61 Modesto 2006 422 yes 1,575 1,575 200 Y 62 Modesto 2004 390 yes 2,200 2,200 200 Y 63 Modesto OOS 2006 500 NP(d) NP(d) NP(d) OOS [Under construction] 64 Modesto 2005 430 yes 1,800 1,800 200 Y 65 Modesto 2000 379 yes 2,000 2,000 200 Share with Tank 5 66 South Modesto OOS NP(d) NP(d) yes 1,350 200 Share with Tank 10 OOS(f) [Mechanical] 100 South Modesto 1958 127 no 650 650 40 204 Modesto 1954 256 no 1,450 1,450 150 211 Modesto 1974 215 no 1,450 1,450 100 212 Modesto 1973 169 no 1,000 1,000 100 214 South Modesto OOS 1964/90 162 no 400 40 OOS(c) [Nitrates] 216 South Modesto 1960/88 200 no 550 550 40 217 South Modesto 1949/72 232 no 400 400 40 223 South Modesto 1940 134 no 400 400 40 Share with Tank 8 225 Modesto 1946/56 320 no 1,200 1,200 150 Y 226 Modesto OOS 1963 235 no 675 40(e) OOS(c) [Arsenic] 229 Modesto 1950/85 230 no 425 425 50 232 Modesto 1949 81 yes 775 775 75 236 Modesto OOS 1950 224 no 750 75 OOS(c) [Nitrates] 237 Modesto 1960/86/87 300 no 630 630 40 241 Modesto 1953 217 no 350 350 40 247 Modesto 1964 225 no 560 560 40 250 Salida 1949/85 246 no 835 835 75 259 Modesto 1960/78 344 no 400 400 40 262 Modesto 1954/75 290 no 350 350 40 264 Modesto 1958/83 428 no 700 700 40 265 Modesto 1960 300 no 500 500 40 267 Modesto 1951 270 no 1,190 1,190 100 269 Modesto 1959 265 no 750 750 50 277 Modesto 1976 257 no 1,000 1,000 100 278 Modesto 1972 270 no 800 800 100 279 Modesto 1971 208 no 800 800 100 Y 281 Salida 1979 365 no 480 480 100 283 Modesto OOS 1980 165 no 800 75 OOS(c) [Uranium] 284 South Modesto 1981 224 no 750 750 75 Table 1. Existing Groundwater Well Production Information for the Contiguous Service Area(a) Remarks City Well Number Depth Pump HP Gravel Packed Date Drilled Area Well Status(c) Existing Backup Power West Yost Associates Last Revised: 10/5/2009 Page 1 of 2 City of Modesto Engineer's Report Appendix A Facilities Inventory TM ---PAGE BREAK--- ---PAGE BREAK--- Pump Available Capacity(a) Capacity(b) [ft] [gpm] [gpm] Table 1. Existing Groundwater Well Production Information for the Contiguous Service Area(a) Remarks City Well Number Depth Pump HP Gravel Packed Date Drilled Area Well Status(c) Existing Backup Power 285 Modesto OOS 1984 300 no 1,000 100 Y OOS(c) [Nitrates] 287 South Modesto 1954 102 yes 750 750 75 288 Salida 1986 230 no 650 650 50 290 Salida 1987 304 no 633 633 50 291 Modesto 1988 268 no 500 500 75 292 Modesto 1988 267 no 850 850 75 293 Modesto OOS 1988 256 no 825 100 Share with 294 & 296 OOS(c) [Nitrates] 294 Modesto 1989 345 no 1,325 1,325 100 Share with 293 & 296 296 Modesto 1991 298 no 900 900 75 Share with 293 & 294 297 Salida 2000 322 no 1,300 1,300 100 298 Salida 1990 324 no 1,200 1,200 100 Y 299 Salida 1990 258 no 450 450 100 Y 300 Modesto 1990 368 no 700 700 75 301 Modesto 1991 156 no 500 500 40 Share with Tank 6 304 Modesto OOS 1991 172 no 525 40 Share with Tank 6 OOS(c) [Uranium] 305 South Modesto 1991 344 no 750 750 75 Share with Tank 8 307 Modesto 1993 268 no 1,050 1,050 100 308 Modesto 1993 256 no 850 850 75 310 Modesto 1994 330 no 1,320 1,320 150 Y 312 Modesto 2002 355 NP(d) 1,000 1,000 100 313 Modesto 2000 322 NP(d) 1,175 1,175 100 Y Total Available System Pumping Capacity [gpm] 106,574 Total Pumping Capacity without 2009 Out of Service Wells [gpm] 82,424 Actual System Pumping Capacity [gpm] 82,424 Actual System Pumping Capacity [mgd] 119 Based on information provided by City. Does not include wells out of service for water quality or Pump Repair. OOS = Out of service well per Wells Out of Service in July 2009 Report. NP = Information not provided. Pump HP per 2002 Well Directory. Construction of the Galas well has recently been completed, but it is not yet operational. West Yost Associates Last Revised: 10/5/2009 Page 2 of 2 City of Modesto Engineer's Report Appendix A Facilities Inventory TM ---PAGE BREAK--- Technical Memorandum October 5, 2009 Page 6 West Yost Associates o:\c\418\02-07-22\wp\ER\20091031ceA1AppA 4.2 Booster Pumping Facilities The City’s pumping capacity can be separated into two categories: groundwater well pumps and booster pump stations at each tank. Within the contiguous service area, there are 7 active booster pump stations (one is owned and operated by MID). Table 3 details the pumping capacity, the presence of backup power, and other information for each booster pumping facility. 4.3 Pipelines The existing contiguous service area’s system consists of approximately 940 miles of pipelines, which are shown on Figure 1. Existing distribution pipeline sizes range from 2 to 12 inches in diameter, along with larger transmission mains ranging in size from 14 to 24 inches in diameter. The MID owned transmission mains range in size from 24 to 42 inches in diameter. The older pipelines are found in the Downtown and former Del Este service areas of the City and are primarily constructed of cast iron, welded steel, or asbestos cement. Sometimes ductile iron and reinforced concrete pipe are found in mains exceeding 16 inch in diameter. A portion of the transmission pipelines traversing the City is owned by MID and treated surface water is discharged into either the former Del Este system or the City system through a number of turnouts. Originally, each turnout was to be equipped with a butterfly valve, flow control valve, and meter. However, these flow control valves and meters were only installed on the Del Este turnouts. Meters and flow control valves were never constructed on the original City turnouts. When the City acquired the Del Este system, the former Del Este flow control valves and meters were removed. Currently, each turnout is equipped with a butterfly valve, which does not allow flow or pressure to be regulated to the degree necessary to control a hydraulic system of the City’s complexity. 5.0 RECENT SYSTEM IMPROVEMENTS The City has made a number of improvements to the contiguous service area over the past few years. These system changes include the following: Constructed 4 new wells: Well 61 (Kaiser), Well 62 (Freedom), Well 64 (McKinney- Colony) and Well 66 (Galas). Three of which are currently operational (Well 66 is not). Replaced, upsized, or installed approximately 50,000 linear feet of water distribution and transmission mains; Installed (or have construction plans to install) treatment equipment and/or blending lines to bring Wells 49, 236, and 283 back-in-service; Constructed 0.7 MG Galas Tank in South Modesto, referenced as Tank 10, in Table 2; and, Replaced booster pump stations at Tanks 6, 7, and 8 to increase capacity and reliability for South Modesto service area. ---PAGE BREAK--- Pump Rated Capacity Existing Backup HP Unit 1 Unit 2 Unit 3 Unit 4 Unit 5 [gpm](a) Power(b) Booster Pump Stations Tank 3 Modesto NP(c) 600 600 600 600 2,400 Y Tank 4 Modesto NP(c) 950 950 950 910 3,760 Y Tank 5 Modesto NP(c) 950 900 950 950 3,750 Y Tank 6 Modesto NP(c) 2,475 2,460 2,515 7,450 Y Tank 7 Modesto NP(c) 2,450 2,450 2,450 7,350 Y Tank 8 Modesto NP(c) 2,570 2,570 2,570 7,710 Y Tank 10 (Galas Tank) South Modesto NP(c) 2,085 2,085 2,085 6,255 Y MID Terminal Reservoir Modesto NP(c) 13,900 13,900 6,950 6,950 13,900 55,600 Y Total Booster Pump Station Capacity [gpm] 94,275 Total Booster Pump Station Capacity [mgd] 136 Pump capacity based information provided by City Staff. Backup power information provided by City Staff. NP = Information not provided Table 3. Summary of Existing City Booster Pumping Facilities Pump Station Area Pumps [Capacity, gpm] Remarks West Yost Associates Last Revised: 10/5/2009 City of Modesto Engineer's Report Appendix A Facilities Inventory TM ---PAGE BREAK--- ---PAGE BREAK---