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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: March 30, 2010 Project No.: 418-02-07-22 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 Buildout Water System for the Del Rio Outlying Service Area (Del Rio TM) In the mid 1990’s the City of Modesto (City) acquired the former Del Este Water System, which included the communities of Grayson, Hickman, Del Rio, the City of Waterford, 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 Engineer’s Report Project, the City has requested West Yost Associates (WYA) to provide an individual hydraulic assessment of each of these separate systems. The hydraulic evaluation of the Community of Del Rio (Del Rio) water system is addressed in this technical memorandum. 1.0 SUMMARY OF FINDINGS 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. In addition, water supply requirements at buildout were evaluated; additional demands at buildout are minimal and do not require a change in the proposed facility plan. 1.1 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. Peak Hour and Maximum Day demand were calculated as 1,898 gallons per minute (gpm) and 815 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 was sufficient to meet Maximum Day demand conditions, however it was not sufficient to meet Peak Hour and Maximum Day demand plus fire flow conditions. Therefore, an additional new production well and back up generator, as well as a storage tank, booster pump station, and back up generator, are required to reliably meet the existing Peak Hour water and Maximum Day plus fire flow system demands. It is also recommended that a standby generator be installed at Well 271 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\20091031ceH1AppH 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 established as 0.25 x Maximum Day demand. Fire flow demand was established as 1,500 gpm for a 2-hour duration. Emergency storage was established as 1.00 x the average day demand. Approximately 0.23 MG of storage is required to meet existing City storage criteria under reliable pump capacity conditions. Therefore, a 0.23 MG storage tank and 1.0 mgd pump station is recommended to provide the additional storage. 1.3 Existing System WYA’s hydraulic modeling of the Del Rio water service area indicates that the existing supply system of three operational wells cannot maintain a minimum system pressure of 40 pounds per square inch (psi) during a simulated Peak Hour demand, or 20 psi residual system pressures during a concurrent simulated Maximum Day plus fire flow demand condition, as required by the City’s water system design criteria. To correct these existing system deficiencies, water system infrastructure to provide additional supply and system reliability for existing users must be constructed. Recommended capital improvements to the existing Del Rio water system are listed below, and anticipated to cost approximately $4.9M, as detailed in Table 7 of this TM. Construct a 1000 gpm replacement production well and backup generator for Well 271; Construct new production well with a pumping capacity of approximately 1,000 gpm, and backup generator; Install a new 0.23 MG storage tank, associated 1.0 mgd pump station, and backup generator to meet Peak Hour and Maximum Day plus fire flow demands; and Construct 4,710 linear feet of new pipeline to improve system reliability and capacity. A proportionate share of the new 1000 gpm well and new distribution pipeline is to serve the buildout population, and will be reimbursed by future customers as discussed below. 1.4 Buildout System The existing Del Rio water system is approximately 57 percent built out (the buildout system boundary is consistent with the Del Rio Community Plan presented in the County’s General Plan dated October 1994). A large portion of this service area is owned by a private country club and golf course. Therefore, demands associated with this area were assumed to remain constant in the future. The golf course irrigation system has a private water source and does not impose a demand on the public water system. However, additional development in other areas of the Del Rio future system are anticipated to increase the Del Rio service area demands by approximately 0.68 mgd (473 gpm), to a total of 1.30 mgd (903 gpm). ---PAGE BREAK--- Technical Memorandum March 30, 2010 Page 3 West Yost Associates o:\c\418\02-07-22\wp\er\20091031ceH1AppH It has also been assumed that all private water systems will continue to be private; future private system facility needs were not evaluated as part of the analysis completed by WYA. In addition to the water system improvements recommended above, the following system improvements will be required to provide reliable service to future customers within the Del Rio future buildout service area: 15,000 linear feet of new pipeline; A proportionate share of the 3,110 lineal feet of pipeline installed as part of the existing system improvements; A proportionate share of the new well and backup generator recommended to be drilled/constructed as part of the existing improvements; and An additional 1 mgd in pumping capacity for the booster pump station located at the above ground storage tank (total capacity will be 2.0 mgd). Costs for these buildout system improvements are estimated to be $5.3M, as detailed on Table 10 of this TM. 2.0 INTRODUCTION In 2002, the City requested WYA to provide engineering services to assist in the conversion, updating, enhancement and calibration of a water system hydraulic model for the Del Rio water system. This model has been updated to reflect demands in 2006 and other current conditions. Using the methodology described in this TM, WYA developed a hydraulic network analysis model of the Del Rio water distribution system to allow computer simulations of various demand 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 Del Rio water system, WYA completed the steps listed below: Used pipeline shapefiles of the Del Rio system, exported from the City’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 Del Rio water system. ---PAGE BREAK--- Technical Memorandum March 30, 2010 Page 4 West Yost Associates o:\c\418\02-07-22\wp\er\20091031ceH1AppH Evaluated existing water demands to ensure proper distribution of demands in the hydraulic model. Conducted a calibration of the hydraulic model to verify that the model could replicate field-observed system pressures. 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; SCADA and other operational pressure and flow data, hydrant flow data; and land use and available production data. Based on this water system information, WYA developed the Del Rio existing water distribution system hydraulic model under 2002 conditions. Since the development and calibration of the hydraulic model in 2002, there have been changes to the Del Rio water system. These changes include metering the entire system in 2003 and installing standby generators at Wells 282 and 289. Demands have been updated based on recent production data and updated peaking factors. Also, due to refinements in the GIS shapefile, the existing service area has increased from 330 acres to 350 acres. The 2002 model has been updated to reflect these changes in system infrastructure and demands. This TM presents the updates performed, model results, and recommended facility improvements. This memo is organized as follows: Service Area Existing Water System Del Rio Hydraulic Model Existing Water Supply System Evaluation & Recommendations Buildout Water Supply System Evaluation & Recommendations Summary of Existing and Buildout Recommendations 3.0 SERVICE AREA The Del Rio service area is located approximately 4 miles north of the City of Modesto (see Figure 1 inset). The Del Rio water system currently serves 343 residential dwelling units, and encompasses a service area containing approximately 350 acres. At future buildout of the Del Rio service area based on the boundary in the Stanislaus County General Plan, the service area will include approximately 590 acres. This area is primarily residential with a very large golf course (approximately 1/3 of the total area) located in the heart of the service area, and is considered 57 percent developed. The Del Rio water service area was originally provided with water service by the Del Este Water Company, but in the mid 1990’s the City of Modesto acquired the Del Este system and took over water service. There are also some parcels in the Del Rio service area that are being served by groundwater, and are not served by the City of Modesto’s water system. ---PAGE BREAK--- Technical Memorandum March 30, 2010 Page 5 West Yost Associates o:\c\418\02-07-22\wp\er\20091031ceH1AppH 4.0 EXISTING WATER SYSTEM The Del Rio water system includes three existing wells, no storage tanks, and approximately 41,000 linear feet of pipeline. Existing Del Rio pipelines vary in size from 4-inches, up to 10-inches in diameter, and are constructed of steel pipe. Currently, there are no interconnections with any other water systems. However, the City of Modesto contiguous water service area is within 4 miles of Del Rio; the possibility of inter-connecting these two independent water systems could be explored. 4.1 Sources of Supply 4.1.1 Wells The Del Rio water system is solely supplied by groundwater. The system includes three existing wells that are all operational; these wells discharge groundwater directly into the distribution system. Well 282 receives granulated activated carbon (GAC) treatment at the wellhead to treat dibromochloropropane (DBCP). Well 282 had a backup generator installed in 2005 and Well 289 had a backup generator installed in 1999. The well locations are shown on Figure 1. Well characteristics are summarized in Table 1. Table 1. Well Characteristics(a) History Pump Data Well Construction Details(d) Well No. Address Year Drilled Rated Pump Capacity (at 60 psi), gpm(d) Rated Hp Standby Power Treatment System Casing Diameter (inches) Gravel Packed Depth of Annular Seal Casing Depth Perforated From/To Total Depth 271 1260 Country Club 1956 395 20 None 14/12/10 No NP(b) 284 124-284 [PHONE REDACTED] Hillcrest Drive 1980 1080 75 Yes GAC(c) 16/14 No 52 275 139-271 [PHONE REDACTED] Beltis Drive 1987/91 1090 75 Yes None 14/12 No NP(b) 360 None 368 Based on information provided by the City. GAC = Granulated Activated Carbon NP = Not Provided by City Based on data collected upon well completion. Pump efficiency tests were performed on all wells in 2007. Results of those tests are shown in Table 2. Compared to the rated pump capacities shown in Table 2, the well pumps are currently pumping between 50 percent to 93 percent of their initial capacities. In particular, Well 271 is currently pumping at only 50 percent of its initial production capacity. This well is approximately 50-years old, and is near the end of its expected useful life of 35 to 50 years. (useful life changes ---PAGE BREAK--- Technical Memorandum March 30, 2010 Page 6 West Yost Associates o:\c\418\02-07-22\wp\er\20091031ceH1AppH depending on site specific hydrogeologic conditions). The production decrease observed in Well 271 is probably due to incrustation of the well screens, integrity of the well casing, and other age-related matters. Well 271 is recommended for replacement in lieu of rehabilitation, due to its age. Table 2. Well Pump Tests(a) Well No. Date Tested Motor HP Measured Flow, gpm Static Level, ft(b) Pumping Level, ft(b) Discharge Pressure, psi Water HP 271 2007 20 200 49 55 60 8.6 282 2007 75 1,000 43 51 50 40.5 289 2007 75 800 59 109 60 55.6 Based on recent well pump test information provided by the City. 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. Table 3. Summary of Del Rio Service Area Production in 2008(a) Well 271 Well 282(b) Well 289 Month gallons MG gallons MG gallons MG January 14,140 0.01 106,529 0.11 6,247,099 6.25 February 5,304 0.01 14,847 0.01 6,945,248 6.95 March 8,356 0.01 1,026,387 1.03 13,078,351 13.08 April 14,451 0.01 3,505,977 3.51 17,101,318 17.10 May 48,796 0.05 5,755,163 5.76 19,693,002 19.69 June 241,557 0.24 7,192,691 7.19 20,490,690 20.49 July 728,731 0.73 8,056,626 8.06 21,278,320 21.28 August 663,379 0.66 8,034,301 8.03 21,289,934 21.29 September 374,610 0.37 6,535,759 6.54 18,934,532 18.93 October 2,741 0.00 3,702,475 3.70 16,953,352 16.95 November 3,782 0.00 709,308 0.71 11,905,800 11.91 December 5,134 0.01 20,525 0.02 7,732,451 7.73 Subtotal 2,110,982 2.11 44,660,586 44.66 181,650,097 181.65 Total Production 228.42 Data provided by the City of Modesto on September 4, 2009, from the file well flow totals 2002 to present.xls”. Well equipped with GAC well head treatment unit. ---PAGE BREAK--- Technical Memorandum March 30, 2010 Page 7 West Yost Associates o:\c\418\02-07-22\wp\er\20091031ceH1AppH 4.1.2 Wellhead Treatment A GAC wellhead treatment facility currently exists at Well 282 and treats the groundwater for dibromochloropropane (DBCP) prior to discharge into the distribution system. 4.1.3 Storage There are currently no storage facilities or pumping plants (other than the well pumps) in the Del Rio water service area. 4.1.4 Pipelines General knowledge of the Del Rio pipeline main locations and material type was gained through discussion with City of Modesto Operations staff. Pipelines within the service area range from 4-inch to 10-inch diameter, and are constructed of steel or polyvinyl chloride (PVC). 5.0 DEVELOPMENT OF THE DEL RIO HYDRAULIC MODEL WYA developed and calibrated a hydraulic model of the Del Rio water service area using MWH Soft’s H2ONET hydraulic modeling software. A summary of the detailed development of this model is included in Attachment A of this TM. 6.0 EVALUATION OF EXISTING WATER SUPPLY SYSTEM 6.1 Overview This section presents the hydraulic evaluation of Del Rio’s 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, and Maximum Day Demand Plus Concurrent Fire Flow. 6.2 Potable Water Demands Average day potable water demands for the existing Del Rio system were calculated based on metered water production data 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 2003 through 2007. The Peak Hour peaking factor was developed based on a 2-year average from 2006 through 2007. ---PAGE BREAK--- Technical Memorandum March 30, 2010 Page 8 West Yost Associates o:\c\418\02-07-22\wp\er\20091031ceH1AppH Table 4. Water Demand Peaking Factors 2006 Demands Demand Condition Peaking Factor(a) mgd(b) gpm Average Day 0.62 430 Maximum Day 1.90 x Average Day 1.17 815 Peak Hour 4.41 x Average Day 2.73 1,898 Based on available water production data for the Del Rio service area. Peaking factors were provided by the City as Max-Day Peak Factor.xls on 7/31/08 and Peak-hour tabulation - Outlying Areas.xls on 8/1/08. mgd = million gallons per day. 6.3 Pumping Capacity Evaluation The Del Rio service area is supplied exclusively by groundwater produced by three 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 2,000 gpm. However, for water supply planning purposes, this groundwater supply (groundwater pumping capacity) must be reduced to account for well or wells that could be out of service at any given time due to mechanical breakdowns, maintenance, or other operational issues. This reduced pumping capacity is defined as the Reliable Pumping Capacity. The City of Modesto has defined the Reliable Pumping Capacity as the system’s groundwater pumping capacity assuming the largest well is out of service. As shown on Table 5, the current total Reliable Pumping Capacity of 1,000 gpm (without Well 282) is sufficient to meet existing Maximum Day demands of 815 gpm. However, it is not sufficient to meet Peak Hour demands of 1,898 gpm. This Reliable Pumping Capacity is also not sufficient to meet the existing Maximum Day plus concurrent fire flow demand of 2,315 gpm. Therefore, an additional new production well and back up generator, as well as a storage tank, booster pump station, and back up generator, are required to reliably meet the existing Peak Hour water and Maximum Day plus fire flow system demands. It is recommended that the new well be located on the western portion of the service area, as discussed in the future system analysis. The locations of the proposed facilities are for planning purposes only and should be developed further in future pre-design studies. ---PAGE BREAK--- Technical Memorandum March 30, 2010 Page 9 West Yost Associates o:\c\418\02-07-22\wp\er\20091031ceH1AppH Table 5. Summary of Existing Del Rio System’s Supply Facilities Pump Name Efficiency, percent Standby Power Existing Capacity, gpm(a) Existing Maximum Day Demand, gpm Existing Peak Hour, gpm Existing Maximum Day plus Concurrent Fire Flow Demand, gpm Well 271 45 No 200 Well 282 60 Yes 1,000 Well 289 66 Yes 800 Total Supply Capacity 2,000 815 1,898 2,315 Total Reliable Supply Capacity 1,000 Adequate Deficient Deficient Based on recent pump test information. Pump tests conducted by City operations staff. 6.4 Storage Capacity Evaluation Criteria have been defined 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 Del Rio 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. Since Del Rio is entirely dependent on the groundwater basin for storage, there is a storage reliability issue. In order to be certain that sufficient supply is available for operational, fire flow, and emergency demands, a storage reservoir with a usable capacity of 0.23 MG is recommended, as shown in Table 6. Constructing a storage tank is more economical than constructing another well, and the system benefits from the additional diversity of groundwater supply. ---PAGE BREAK--- Technical Memorandum March 30, 2010 Page 10 West Yost Associates o:\c\418\02-07-22\wp\er\20091031ceH1AppH Table 6. Summary of Required Above Ground Storage Storage Component Component Detail Storage, MG Operational 0.25 x Maximum Day demand 0.29 Fire 1500 gpm for 2 hours 0.18 Emergency 1.00 x average day demand 0.62 Subtotal 1.09 Groundwater Credit 60% of reliable pumping capacity 0.86 Total Usable Storage Required 0.23 Data based on the Water Demand Peaking Factors presented in Table 4. Sixty percent of existing reliable groundwater pumping capacity (without Well 282). 6.5 Existing Distribution System Evaluation Hydraulic analyses were conducted to identify areas of the Del Rio system in which minimum pressure could not be maintained, or where velocities and/or head losses were found to exceed City of Modesto water system design standards. Detailed discussion is provided in the following sections. 6.5.1 Peak Hour Demand Conditions The Peak Hour demands for Del Rio’s potable water distribution system under existing conditions are approximately 2.73 mgd (1,898 gpm). This existing Peak Hour demand condition was simulated in the model. Results from the hydraulic analysis indicated that the existing distribution system could not reliably deliver these demands at the City’s minimum pressure criteria of 40 psi, even with all three existing wells in service. This analysis also indicated that head losses in existing pipelines were able to meet the City’s criteria of < 7 feet per 1,000 feet (ft/kft) and the velocity criteria of < 7 feet per second (fps). However, after including the 0.23 MG of storage described previously, and adding new distribution facilities of this storage tank, the pressure deficiency shown in Figure 3 is relieved. A 1.0 mgd booster pump and station of the 0.23 storage tank is recommended to provide sufficient supply to meet the Peak Hour demand condition. It is recommended that the new above ground tank and booster pump station be located in the eastern portion of the service area, near Well 289. The tank and booster pump location is for planning purposes only and should be developed further in future pre-design studies. In addition to providing needed capacity, the tank and booster pump station will also increase the reliability of the system in the event that Well 289 is taken offline for maintenance. 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. For this analysis, all areas are assumed to be residential land use, with a fire flow requirement of ---PAGE BREAK--- Technical Memorandum March 30, 2010 Page 11 West Yost Associates o:\c\418\02-07-22\wp\er\20091031ceH1AppH 1,500 gpm for 2 hours. Based on the analysis of the Maximum Day plus fire flow demand condition, Del Rio’s existing water system cannot deliver the minimum pressure requirement of 20 psi to some existing areas (see Figure even with all three existing wells in operation. The system is unable to meet minimum pressure requirements in the eastern and western portions due to insufficient supply and pumping capabilities. This lack of supply can be mitigated with the construction of a new well in the northwest portion of the service area. The new facilities will provide Reliable Pumping Capacity during a fire flow demand condition, as shown in Figure 5. With the addition of a new well, the existing 10-inch diameter pipeline along Country Club Drive is no longer adequately sized to convey supply to the eastern side of the service area. For this reason, the proposed storage tank and pump station discussed above are recommended to be located in the eastern portion of the service area, near Well 289. The facilities improvements are shown in Figure 6. In addition, installation of 1,600 linear feet of new pipelines is recommended to increase system circulation and redundancy, and provide sufficient flow under fire flow conditions. These pipelines are shown on Figure 6 and detailed in Table 7. 6.6 Recommended Existing System Improvements Based on the analyses detailed above, WYA recommends that the City replace Well 271, complete construction of a new well with an approximate pumping capacity of 1,000 gpm (a proportionate share of the cost of this new well to be paid by future customers), and a 0.23 MG storage tank with associated 1.0 mgd pump station to ensure adequate storage and supply for the existing system. To help circulate this additional flow, new pipelines are needed in a few key locations. In addition, the City should install backup generators at all wells, so that reliable service can be maintained in the event of a power outage. These improvements are shown in Figure 6 and detailed with costs in Table 7 (does not include costs for any well head treatment facilities required to meet water quality standards, if required). With the completion of these recommendations, the existing water system can meet the City of Modesto’s required design / system criteria. 7.0 EVALUATION OF BUILDOUT WATER SUPPLY SYSTEM The future Del Rio service area will include additional acreage that will expand the service area in several directions. As illustrated in Figure 7, there will be expansion in three distinct regions in the Del Rio: the northwest, east, and southwest. According to the County’s General Plan, and more specifically, the Del Rio Community Plan, development in the future northwest and eastern portions of the service area are proposed as “future planned development land use,” and development in the southwestern area is planned to be residential. Using a water duty factor of 2.70 afa/ac for the outlying service area, this additional area will increase potable water demand by approximately 0.68 mgd to a total average day demand of 1.30 mgd. This factor is based on water duties calculated in the “Draft Water System Demand Evaluation” (WYA, March 15, 2008). Using peaking factors of 1.90 and 4.41, the demands for Maximum Day and Peak Hour are 2.47 mgd and 5.74 mgd respectively. ---PAGE BREAK--- CIP CIP Unit Cost Cost ID Reason Item Unit Quantity Pipelines FF01 Fireflow Along Carver Road between Riveroaks Drive and Thunderbird Drive 8-inch lf 230 101 23,000 FF02 Fireflow Along Thunderbird Drive between Oakmont Drive and Del Rio Drive 8-inch lf 410 101 42,000 FF03 Fireflow Along Oakmont Drive between Thunderbird Drive and Country Club Drive 8-inch lf 760 101 76,000 FF04 Fireflow Along alley between Oakmont Drive and Del Rio Drive south of Tamarisk Drive 8-inch lf 200 101 20,000 SU01 Supply Proposed Tank Site to Distribution System (North and West) 10-inch lf 2,370 123 122,000 SU02 Supply Proposed New Well Site to Distribution System (Northwest) 10-inch lf 740 123 46,000 Storage Tank Supply 0.23 MG Storage Tank ls 1 1,080,000 1,080,000 Supply 1.0 mgd Pump Station Well(d) Supply New Well with 1,000 gpm pump, backup generator, and SCADA ls 1 666,000 666,000 Supply Replacement of Well 271 and backup generator ls 1 1,200,000 1,200,000 Subtotal (Overall Program) 3,275,000 50% Contingency 1,637,500 Total Estimated Construction Cost for Recommended Existing System CIP 4,912,500 Cost based on existing system's proportionate share of the capacity of this required project (approximately 50% for booster station, 100% for storage tank; 57.8% composite). Costs provided by City. Cost includes cost for backup/standby power generators and SCADA for the pump station. Table 7. Recommended CIP Program for Existing Del Rio 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. Cost does not include cost of well head treatment or other facilities to meet water quality standards, if necessary. Well will be contained in a building to address security, visual, and noise needs. Does not include site specific facilities. Actual pipeline configurations and well and tank / pump station locations could change when specific development plans become available. Cost based on existing system's proportionate share of the capacity of this required project (approximately 42%). Cost based on existing system's proportionate share of the capacity of this required project (approximately 50%). West Yost Associates o:\c\418\02-07-22\wp\er\20091031ceH4 T7 Last Revised: 09/11/08 City of Modesto Engineer's Report Appendix H Del Rio TM ---PAGE BREAK--- Technical Memorandum March 30, 2010 Page 13 West Yost Associates o:\c\418\02-07-22\wp\er\20091031ceH1AppH In addition to the existing system improvement recommendations, 15,000 feet of future backbone pipelines were also added to the hydraulic model to serve these buildout areas. For purposes of this analysis, existing private water systems shown in Figure 7 were assumed to remain private in the future and were not included in the future infrastructure needs of future Del Rio customers. 7.1 Pumping Capacity Evaluation The recommended system upgrades to the existing water system, which include one new production well, replacement of Well 271, and a new storage reservoir and pump station will increase the Reliable Pumping Capacity of the Del Rio water system to approximately 3,494 gpm. This capacity is insufficient to meet buildout Peak Hour demands of 3,986 gpm, as shown in Table 8. Additional pumping facilities are required to ensure that the service area has sufficient pumping capacity during peak demand periods at buildout. It is recommended that a future CIP well be constructed to meet the peak demands of future customers. This well is the same as the recommended new well for the existing system, however half of the cost will be allocated under the existing CIP cost and the other half of the cost will be allocated under the future CIP cost, as shown in Tables 7 and 10. Table 8. Summary of Future System’s Supply Facilities Pump Name Efficiency, percent Standby Power Existing/ Anticipated Well or Pump Capacity, gpm(a,b) Future Maximum Day, gpm Future Peak Hour, gpm Future Maximum Day Plus Fire Flow, gpm Well 271 45 No 0 Well 282 60 Yes 1,000 Well 289 66 Yes 800 New Well(e) Yes(c) 1,000 Well 271 Replacement Yes(c) 1,000 New Tank and Pump Station(d,e) Yes(c) 694 Total Supply Capacity 4,494 1,712 3,986 3,212 Total Reliable Supply Capacity 3,494 Sufficient Deficient Sufficient Based on pump test flow from recent 2007 pump tests conducted by City operations staff. Anticipated capacity based on assumed well pump capacity of 1,000 gpm for new well; 1,000 gpm for Well 271 replacement, and tank booster pump capacity of 1.0 mgd (694 gpm). Construction of future facilities will include standby power. Assumes new tank will typically operate using a single pump, with backup pumping only as needed. Recommended facility to mitigate existing water system deficiencies. The new well should be located in the western part of the future Del Rio service area. This is the preferred location because the eastern and western portions of the Del Rio service area are inter-connected by only a single 10-inch diameter pipeline along Country Club Drive. Therefore, each of these service areas (eastside and westside) need to be relatively, individually ---PAGE BREAK--- Technical Memorandum March 30, 2010 Page 14 West Yost Associates o:\c\418\02-07-22\wp\er\20091031ceH1AppH self-sufficient, in the event of a pipeline break. With the construction of this future CIP well in the western service area, sufficient supplies and groundwater storage will be available in the western service area. Sufficient supplies and storage will also be available in the eastern portion of the service area. 7.2 Storage Capacity Evaluation The anticipated average day buildout demand of 1.30 mgd will increase the total required storage to 2.10 MG. With the 0.23 MG tank that is proposed for existing operations, and available groundwater credit for storage, no additional above ground storage, will be needed to meet buildout storage requirements (see Table Table 9. Summary of Required Above Ground Storage Storage Component Component Detail Storage, MG Operational 0.25 x Maximum Day demand 0.62 Fire 1500 gpm for 2 hours 0.18 Emergency 1.00 x average day demand 1.30 Subtotal 2.10 Existing CIP Storage (0.23) Groundwater Credit 60% of reliable pumping capacity(a) (3.02) Total Additional Storage Required 0.00 Reliable capacity based on production from Wells 282, Well 289, replacement Well 271, and one new well installed to meet existing demand. 7.3 Buildout Distribution System Evaluation Hydraulic analyses were conducted to identify if buildout demands would require the need for additional facilities beyond those required to meet current demands. A discussion is provided in the following sections. 7.3.1 Peak Hour Demand The Peak Hour demands for Del Rio’s potable water distribution system under future conditions are approximately 5.74 mgd. This Peak Hour demand condition was simulated in the model and the results indicated that the existing distribution system (with the recommended existing system improvements assumed to be constructed and operational), could not adequately deliver these demands at a minimum pressure of 40 psi without additional system improvements. This analysis also indicated that head losses in existing pipelines were able to meet the City’s criteria of < 7 feet per 1,000 feet (ft/kft) and the velocity criteria of < 7 feet per second (fps). The solution to this pressure deficiency is to provide additional supplies to both the western and eastern portions of the future Del Rio service area. ---PAGE BREAK--- Technical Memorandum March 30, 2010 Page 15 West Yost Associates o:\c\418\02-07-22\wp\er\20091031ceH1AppH Since the pressure deficiencies are located in both the western and eastern portions of the service area, as illustrated in Figure 8, additional pumping capacity in the eastern portion of the service area could be provided by expanding the booster pump station at the above ground storage tank, and additional supply could be provided by the proposed new well for the existing system. The new well should be placed in the northwestern portion of the service area. With these additional facilities and the completion of the recommended existing system improvements, system pressures above 40 psi can be maintained, as shown in Figure 9. 7.3.2 Maximum Day Plus Fire Flow Demand 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 used in the Del Rio service area (assumed to be residential land use) is 1,500 gpm for 2 hours. Based on our analysis of the Maximum Day plus fire flow demand condition, Del Rio’s future water system can deliver the minimum pressure requirement of 20 psi at all fire flow locations, including the new development areas, assuming all previously identified facility improvements, both existing and future, (including all new wells, storage tanks and associated booster pump stations, and pipelines) are constructed. 7.4 Recommended Buildout System Improvements Based on the analyses detailed above, WYA recommends that the City complete construction of one new well in the northwestern portion of the future service area (to be jointly funded and used by both existing and future customers), and expand the booster pump station at the above ground storage tank by 1.0 mgd (total capacity of 2.0 mgd). This added pumping capacity would ensure adequate supply for estimated Peak Hour demand at buildout. In order to distribute this additional supply to future customers, additional pipelines must also be constructed. These improvements are shown in Figure 10, and detailed with costs in Table 10. Costs presented in Table 10 do not include costs for well head treatment facilities, if any, required to meet water quality standards. 8.0 RECOMMENDED WATER SYSTEM IMPROVEMENTS Based on the evaluation of Del Rio’s water system, we identified the need for various water facility improvements throughout Del Rio’s overall service area. An overview of the recommended facilities necessary to serve the existing and buildout customers of the Del Rio water service area is provided on Figures 6 and 10, respectively. A summary discussion of the prioritized recommended improvements is provided below. ---PAGE BREAK--- CIP CIP Unit Cost Cost ID Reason Item Unit Quantity Pipelines SU01 Supply Proposed Tank Site to Distribution System (North and West) 10-inch lf 2,370 123 168,000 SU02 Supply Proposed New Well Site to Distribution System (Northwest) 10-inch lf 740 123 46,000 Future Future Development Pipelines 10-inch lf 15,000 123 1,836,000 Storage Tank Storage Tank and Booster Pump Station Supply 1.0 mgd Pump Station Expansion at Existing CIP Tank ls 1 787,000 787,000 Well(e) Supply New Well with 1,000 gpm pump, backup generator, and SCADA ls 1 1,333,000 667,000 Subtotal (Overall Program) 3,504,000 50% Contingency 1,752,000 Total Estimated Construction Cost for Buildout of General Plan 5,256,000 Table 10. Recommended CIP Program for Future Del Rio 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. Cost based on future system's proportionate share of the capacity of this required project (approximately 58%). Cost does not include cost of well head treatment or other facilities to meet water quality standards, if necessary. Well will be contained in a building to address security, visual, and noise needs. Does not include site specific facilities. Actual pipeline configurations and well and tank / pump station locations could change when specific development plans become available. Cost based on future system's proportionate share of the capacity of this required project (approximately 50%). West Yost Associates o:\c\418\02-07-22\wp\er\20091031ceH5 T10 Last Revised: 09/11/08 City of Modesto Engineer's Report Appendix H Del Rio TM ---PAGE BREAK--- Technical Memorandum March 30, 2010 Page 17 West Yost Associates o:\c\418\02-07-22\wp\er\20091031ceH1AppH 8.1 Existing System Recommendations The following recommended improvements to Del Rio’s water system are required to ensure that reliable, adequate service can be provided to existing users: Replacement production well for Well 271, with backup generator; New production well (with backup generator), with a pumping capacity of approximately 1,000 gpm (a proportionate share of this well will be used by and paid for by future users); 0.23 MG new storage tank and associated 1.0 mgd pump station with backup generator; and 4,710 linear feet of new pipeline. Locations of the recommended improvements are shown on Figure 6 and detailed in Table 7. The locations of the proposed facilities are for planning purposes only and should be developed further in future pre-design studies. 8.2 Buildout System Recommendations Improvements to Del Rio’s water system are required to ensure that reliable, adequate service can be provided to future users. These improvements include: 15,000 linear feet of new pipeline; A proportionate share, based on Maximum Day demand, of the 3,110 lineal feet of pipeline installed as part of the existing system improvements; A proportionate share of the new well and back up generator recommended to be constructed as part of the existing improvements, based on Maximum Day; and 1.0 mgd additional pumping capacity for the booster pump station located at the above ground storage tank (total capacity will be 2.0 mgd). Locations of the recommended improvements are shown on Figure 10 and detailed in Table 10. The locations of the proposed facilities are for planning purposes only and should be developed further in future pre-design studies. 8.3 Cost Distribution In order to equitably allocate the costs of these new facilities to existing and future Del Rio water service area customers, proportionate costs were determined based on a proportionate share of the hydraulic capacity used. Under the Existing System Program, all facilities, with the exception of approximately 2,370 lineal feet of 10-inch pipeline (pipeline SU01) from the proposed tank to the distribution system and 740 lineal feet of 10-inch pipeline (pipeline SU02) from the proposed new well for the existing and future distribution system, will provide benefits solely for existing customers. The recommended volume of the tank corresponds directly to the storage deficiency associated with the existing water system. ---PAGE BREAK--- Technical Memorandum March 30, 2010 Page 18 West Yost Associates o:\c\418\02-07-22\wp\er\20091031ceH1AppH Storage costs and pipeline costs other than specific costs for the 3,110 (2,370 plus 740 feet) linear feet of pipeline described above will be assigned to existing customers. Cost for the 3,110 linear feet of pipeline required to connect the tank and the future new well to the existing water system will be divided between existing and future customers based on the volume of flow that will be provided for each under a Maximum Day demand condition. This and additional cost distributions are detailed in Table 11. 8.4 Required On-going Rehabilitation Improvements In addition to the need to construct system improvements to meet current water system demands, a prioritized plan to repair or replace aging water system infrastructure is recommended. The decision to repair or replace existing facilities should be based primarily on facility age and condition. Pipelines that have experienced corrosion but have retained adequate structural integrity may often be repaired instead of replaced. Preventive maintenance is usually more cost effective and less disruptive than replacement, maximizes the useful life of the pipeline, and thereby optimizes lifecycle cost. Pipes that have experienced extensive corrosion and do not have adequate structural integrity should be replaced. A system-wide condition assessment is also recommended to evaluate existing pipe conditions and to develop a prioritized replacement program. The program may involve internal and external corrosion evaluations to determine when to replace certain pipelines. Upgrades should include existing pipelines that were part of the older Del Este water system, in addition to any pipeline replacements identified through the prioritization process described above. 9.0 CAPITAL COSTS OF RECOMMENDED IMPROVEMENTS The estimated probable capital costs for the recommended water system improvements to serve Del Rio’s existing and buildout condition are presented in Tables 7 and 10, and a summary of all recommended CIP projects is provided in Table 11. 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 factors. The costs for the facilities do not include costs for annual operation and maintenance, or costs for acquisition of pipeline rights-of-way. ---PAGE BREAK--- CIP Project Existing Future Total Pipelines 8-inch pipeline along Carver Road between Riveroaks Drive and Thunderbird Drive 23,000 0 23,000 8-inch pipeline along Thunderbird Drive between Oakmont Drive and Del Rio Drive 42,000 0 42,000 8-inch pipeline along Oakmont Drive between Thunderbird Drive and Country Club Drive 76,000 0 76,000 8-inch pipeline along alley between Oakmont Drive and Del Rio Drive south of Tamarisk Drive 20,000 0 20,000 10-inch pipeline from proposed Tank Site to Distribution System (North and West)(c) [SU01] 122,000 168,000 290,000 10-inch pipeline from proposed New Well Site to Distribution System (Northwest)(c) [SU02] 46,000 46,000 92,000 10-inch Future Development Pipelines 0 1,836,000 1,836,000 Storage Tank 0.23 MG Storage Tank 2.0 mgd Pump Station 787,000 1,867,000 Wells(d) New Well with 1,000 gpm pump, backup generator, and SCADA 666,000 667,000 1,333,000 Replacement of Well 271 and backup generator 1,200,000 0 1,200,000 Subtotal (Overall Program) 3,275,000 3,504,000 6,779,000 50% Contingency 1,637,500 1,752,000 3,389,500 Total Estimated Construction Cost for Recommended System CIP 4,912,500 5,256,000 10,168,500 Cost based on proportionate share of the capacity of this required project. Cost does not include cost of well head treatment or other facilities to meet water quality standards, if necessary. Well will be contained in a building to address security, visual, and noise needs. Table 11. Recommended CIP Program Cost Distribution(a) Cost Does not include site specific facilities. Actual pipeline configurations and well and tank / pump station locations could change when specific development plans become available. 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. 1,080,000 West Yost Associates o:\c\418\02-07-22\wp\er\20091031H6 T11 Last Revised: 12\03\08 City of Modesto Engineer's Report Appendix H Del Rio TM ---PAGE BREAK--- ---PAGE BREAK--- West Yost Associates o:\c\418\02-07-22\wp\er\20091031ceH2 F2 Last Revised: 11/03/09 City of Modesto Engineer's Report Appendix H Del Rio TM Figure 2. Community of Del Rio - Production by Well (2008) 0 5,000,000 10,000,000 15,000,000 20,000,000 25,000,000 30,000,000 35,000,000 January February March April May June July August September October November December Month Production (Gallons) Well 271 Well 282 Well 289 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 Del Rio’s Hydraulic Model ---PAGE BREAK--- West Yost Associates A-1 o:\c\418\02-07-22\wp\er\20091031ceH2AttA ATTACHMENT A. DEVELOPMENT OF DEL RIO’S HYDRAULIC MODEL WYA developed a hydraulic model of the Del Rio 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 MWH Soft’s 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 Del Rio’s water distribution system hydraulic model are described below: A minimum pipe size of 4 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). Water demands were derived for the Del Rio System based on 2006 production data provided by the City. Peaking Factors Maximum day and peak hour demand factors were calculated using data provided by the City. 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\20091031ceH2AttA Table 1. Maximum Day Demand Peaking Factor Year Date Max Day, gpd Average Day, gpd Peaking Factor 2003 06/29/03 1,428,408 739,666 1.93 2004 06/15/04 1,123,444 635,972 1.77 2005 07/16/05 1,220,553 619,463 1.97 2006 07/25/06 1,202,494 619,266 1.94 2007 07/14/07 1,174,806 628,271 1.87 Average 1.90 Table 2. Peak Hour Demand Peaking Factor Year Date Peak Hour, gpm Average Day, gpm Peaking Factor 2006 07/25/06 1,937 430 4.50 2007 07/14/07 1,887 436 4.32 Average 4.41 Model Development Node elevations were automatically computed using U.S. Geological Survey Digital Elevation Models (DEM). Pipeline were assigned C-factors based on material types and age as indicated by City Operations staff, ranged from 135 to 100. The water surface elevation for all wells were as modeled as fixed-grade reservoirs, with water surface elevations equal to active water pumping levels as reported in City pump tests. Well pumps were modeled with design point curves as presented in Table 3. Flow and head data points are based on observed flow and computed total dynamic head from City pump tests. Wells 282 and 289 have variable frequency drives (VFDs) to control system pressure. To simulate these VFDs, 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\20091031ceH2AttA Table 3. Well Model Characteristics Modeled with Design Point Curve Well Diameter, in Head, ft Flow, gpm 271 8 194 200 282(a) 8 167 1000 289(a) 8 248 800 Well pump has variable frequency drive. 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. Existing system demands are modeled in demand fields 1 and 2. Future demands are modeled in demand field 3. Existing System Demands The Community of Del Rio existing system demand is based on production data provided by the City for 2006. Additional details to the demands and allocations utilized for this analysis are described below: Metered Customers: While large metered customer loads are typically assigned individually to the closest model node, the Del Rio Service Area metered non-residential demand amounts to only approximately 3 percent of the total, with one large individual account, the Golf Course. Therefore, metered consumption was used for the single large individual account and unmetered residential use was distributed amongst the other nodes. Unmetered residential use is modeled in demand field 1. The golf course is modeled in demand field 2. Unaccounted-for-Water: The City has determined Unaccounted-For-Water is approximately 15 percent of 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 bulk of the demand is by unmetered residential customers, as discussed in the Demand TM. Because the existing Del Rio Service Area is currently fully developed, all parcels were assigned equal demand. The unit demand per parcel is the total consumption (430 gpm average day) divided by number of parcels (353), or 1.22 gpm per parcel. Parcels, and their associated 1.22 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 Del Rio service area has no large industry or dense commercial areas. Therefore, the fire demand of 1,500 gpm was used for the entire service area. ---PAGE BREAK--- West Yost Associates A-4 o:\c\418\02-07-22\wp\er\20091031ceH2AttA Future System Demands Future demands were estimated based on land use information provided by the City of Modesto, as documented in the body of this TM. Figure 7 of the TM shows future development area. Demands were allocated to the model by equally distributing the total estimated demand for new developments to the individual 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 the 2006 average day demand condition EX_MD 2006 Maximum Day Scenario Model of the 2006 maximum day demand condition EX_MDFF 2006 Maximum Day plus Fire Flow Scenario Model of the 2006 maximum day demand plus 1,500 gpm fire flow demand condition EX_PH 2006 Peak Hour Scenario Model of 2006 peak hour demand condition EX_CIP Existing System CIP Scenario Model of existing system CIP recommendations 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 1,500 gpm fire flow demand condition FUT_PH Future Peak Hour Scenario Model of future peak hour demand condition FUT_CIP Future System CIP Scenario Model of future system CIP recommendations Data Sets The Data Sets contained in the model are shown in Tables 5 through 9. ---PAGE BREAK--- West Yost Associates A-5 o:\c\418\02-07-22\wp\er\20091031ceH2AttA Table 5. Demand Sets Demand Set Description Definition EX_AD 2006 Average Day Demand 2006 average day demand (0.62 mgd) EX_MD 2006 Maximum Day Demand 2006 maximum day demand (1.17 mgd) EX_MDFF 2006 Maximum Day w/ Fire Flows Demand 2006 maximum day demand with concurrent 1,500 gpm fire flow condition EX_PH 2006 Peak Hour Demand 2006 peak hour demand (2.73 mgd) FUT_AD Future Average Day Demand Future average day demand (1.30 mgd) FUT_MD Future Maximum Day Demand Future maximum day demand (2.47 mgd) FUT_MDFF Future Maximum Day w/ Fire Flows Demand Future maximum day demand with concurrent 1,500 gpm fire flow condition FUT_PH Future Peak Hour Demand Future peak hour demand (5.74 mgd) Table 6. Pipe Sets Pipe Set Description Definition EX_BASE 2006 Existing System Pipelines Existing system configuration EX_CIP Existing System CIP Pipes Existing system recommended CIP pipeline improvements FUT_BASE Future System Pipelines Future System Configuration FUT_CIP Future System CIP Pipes Future system recommended CIP pipeline improvements Table 7. Pump Set Pump Set Description Definition EX-BASE Existing System Pump Settings Existing system pump operation EX-CIP Existing System CIP Pump Settings Recommended existing system pumps FUT-CIP Future System CIP Pump Settings Recommended future system pumps ---PAGE BREAK--- West Yost Associates A-6 o:\c\418\02-07-22\wp\er\20091031ceH2AttA Table 8. Fire Flow Sets Fire Flow Set Description Definition FF1500 1,500 gpm Fire Flow at Fire Hydrant Nodes This sets up the fire flow analysis at each hydrant node FF-FUT Fire Flow at Fire Hydrants Under Future Buildout Applied 1,500 gpm fire flow at each hydrant node Table 9. 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 with Fire Flow Controls Existing maximum day demand with concurrent fire flow controls EX_PH 2006 Peak Hour Controls Existing peak hour demand controls EX_CIP Existing System 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 with Fire Flow Controls Future maximum day demand with concurrent fire flow controls FUT_PH Future Peak Hour Controls Future peak hour demand controls FUT_CIP Future System CIP Controls Future system CIP recommended controls Calibration The model was calibrated using hydrant test and SCADA information provided by the City. These hydrant tests were performed under varying demand conditions. To verify the accuracy of the model, the pressure differential between static and residual pressures were compared between the actual field test and model results. As shown in Table 10, the model is capable of predicting system pressures within approximately 6 psi of the actual observed field pressures. This level of accuracy is appropriate and acceptable for CIP planning purposes. ---PAGE BREAK--- West Yost Associates A-7 o:\c\418\02-07-22\wp\er\20091031ceH2AttA Table 10. Community of Del Rio Model Calibration Table Hydrant Test Location Actual ∆P Model ∆P Difference S/W Corner of Hye Park and Stewart 53.00 psi 47.23 psi 5.77 psi 608 Atherton Court 46.00 psi 39.54 psi 6.46 psi Model Element Information To provide flexibility in modeling various system configuration, each modeling element was assigned a phase, as listed in Table 11 below. Each phase number corresponds to the modeling element’s system configuration. Table 11. Modeling Element Phase Numbering Convention Phase Configuration 1 Existing System 2 Existing System CIP 3 Future System 4 Future System CIP