Chapter 5.0 POTABLE WATER DISTRIBUTION SYSTEM

Transcription

1 Chapter 5.0 POTABLE WATER DISTRIBUTION SYSTEM This chapter reviews the District s existing water distribution system, evaluates the system s ability to serve existing and projected future water demands, and identifies necessary system improvements. This chapter builds on information presented in previous chapters. The land use and unit demand factors developed in Chapter (Land Use) form the basis for the water demand projections presented here. The system planning criteria presented in Chapter 3 (Water Planning Criteria) define the system performance requirements used to evaluate the adequacy and improvement needs of the District s water system. Lastly, the descriptions of the District s water supply sources and aqueduct connections presented in Chapter 4 (Water Supply and Conservation) provide the necessary background for understanding the source of potable water supply to the District s distribution system. The remainder of this chapter is organized into the following sections: 5.1 Water System Inventory 5. Existing and Future Water Demands 5.3 Hydraulic Model Development and Calibration 5.4 Water System Analysis and Findings 5.5 Recommended Potable Water System Improvements 5.1 Water System Inventory This section presents an inventory of the District s water distribution system, including: District Connections to the San Diego County Water Authority Pressure Zones Pumping Stations Reservoirs (Tanks) Pressure Reducing Stations Pipelines Interagency Service Agreements District Connections to the San Diego County Water Authority The District receives water from the San Diego County Water Authority (Water Authority) through five potable water connections (turnouts) to the Water Authority aqueduct system. The District s connections to the Water Authority were described in Chapter 4 and their locations are depicted in Figure 5-1. The capacity of each connection and the average delivery to the District at each connection during calendar year 007 were presented in Chapter 4 and are repeated in Table 5-1 for ease of reference. The average delivery from the Water Authority is slightly higher than the District s metered average day demand (ADD) of 18.3 MGD, as some of the water delivered goes unbilled. This is discussed further in Section Vallecitos Water District Master Plan

2 Table 5-1 District Connections to the Water Authority 1 Potable Water Distribution System Connection Location Capacity 007 Average Delivery to VWD (1) cfs MGD gpm MGD VAL First Aqueduct VAL 7 Second Aqueduct, south edge of District () 40 6, VAL 8 VAL 9 Second Aqueduct, off North County Distribution Pipeline, northwest corner of District Second Aqueduct, center of District, south of Twin Oaks Diversion Structure , VAL 10 Second Aqueduct, north-center of District, north of Twin Oaks Diversion Structure , Total , Source: 007 VWD Operational Data (1) Based on Water Authority Delivery to the District from January through December 007 () 007 flows for VAL 7 do not include OMWD or CMWD demands. In addition to the deliveries listed in Table 5-1, the District also takes flows at the VAL 7 connection for delivery to the Carlsbad Municipal Water District (MWD) and the Olivenhain Municipal Water District (OMWD). The interagency service agreements governing these deliveries are described in Section (Interagency Service Agreements). These deliveries flow through a dedicated transmission pipeline, the Questhaven Pipeline, to the two agencies. The Carlsbad MWD and OMWD deliveries are therefore accounted for as additional demands in the District s hydraulic model, as further detailed in Section Pressure Zones The varied topography of the District dictates a wide range of pressure zones which are listed in Table 5- and their approximate boundaries are shown in Figure 5-1. The District operates and maintains 6 pressure zones to serve customers with appropriate system pressures. These pressure zones are supplied from the Water Authority connections through a network of pump stations, reservoirs, and pressure reducing stations. Pressure zones within the District are named by the downstream valve setting or base elevation of the tank. The Northern Pressure Zones primarily receive water from the Water Authority VAL 8 and VAL 10 connections. The Central Pressure Zones primarily receive water from the 108 Twin Oaks Reservoirs via VAL 10 and two large pressure reducing stations, and can also receive water from the Water Authority VAL 9 and VAL connections. The Southern Pressure Zones primarily receive water from the Water Authority VAL 7 connection. 1 For additional Water Authority Connection Data, see Technical Memorandum No. 4, Appendix A. 5- Vallecitos Water District Master Plan

3 Ä Vista Irrigation District 900 Tres Amigos 1059 # N TWIN OAKS # Gopher Canyon Rd VAL 8 MOUNTAIN BELLE 1330 N. Twin Oaks North San Marcos Mountain * TWIN OAKS #1& # N TWIN OAKS #1 Rainbow WD # North 18 VAL 10 NORTH North 18 COGGAN 1608 Coggan!"a$ Old Castle Rd Valley Center WD Deer Springs Rd 135 Deer Springs DEER SPRINGS #1 Carlsbad MWD A VAL 9 # 108 Twin Oaks 1500 Palos 175 * Vista La Cienega Richland WULFF # Wulff PALOS VISTA RICHLAND #1 & # PALOMAR Mission Rd Buena Creek Rd Twin Oaks Valley Rd VAL # MEADOWLARK #1 & # Meadowlark Rancho Santa Fe Rd 855 VIA VERA CRUZ SCHOOLHOUSE 1530 San Elijo 130 DOUBLE PEAK SAGE CANYON Las Posas 6 Zone San Marcos Blvd # VAL CORONADO HILLS # Coronado Hills Rincon del Diablo WD Legend #* VWD Sphere of Influence Reservoir Future Zone SDCWA Flow Control Facility OMWD Ü Miles SOURCE: LAFCO SOI - Affirmed VWD GIS Data , provided by District /15/011 KC SD Z:\Projects\IS\VallecitosWaterDistrict\007MasterPlan\mxd\ExistingSystem_W_Fig_5-1.mxd EXISTING WATER SYSTEM FIGURE 5-1 Vallecitos Water District Master Plan

4 Table 5- Pressure Zone and Supply Source Summary HGL (1) Name Supply Source(s) Northern Pressure Zones (Primarily Served by VAL 8 and VAL 10) Tres Amigos Zone VAL Twin Oaks Zone VAL Zone VAL 10, reduced from 1330 Zone 18 North 18 VAL 10, reduced from 1608 Zone Deer Springs Zone VAL 10, pumped from 108 Zone North Twin Oaks Zone VAL 10, pumped from 108 Zone Wulff Zone VAL 10, pumped from 135 Zone Coggan Zone VAL 10, pumped from 108 Zone Central Pressure Zones (Primarily Served by VAL 9, VAL 10 & 108 Twin Oaks Reservoirs) Zone VAL 10 and VAL 9, reduced from 90 Zone Richland Zone VAL 9 and VAL Zone VAL 10 and VAL 9, reduced from 1380 Zone Zone VAL 10 and VAL 9, reduced from 1500 Zone Palos Vista Zone VAL 10 and VAL 9, pumped from 90 Zone Southern Pressure Zones (Primarily Served by VAL 7) (1) () 6 6 La Costa Zone VAL 7, reduced from 815 Zone La Costa Ridge / Melrose Zone VAL 7, reduced from 815 Zone Zone VAL 7, reduced from 815 Zone Alga Zone VAL 7, reduced from 815 Zone Zone VAL 7, reduced from 877 Zone Meadowlark Zone VAL 7, reduced from 877 Zone Zone (formerly Las Posas) VAL Zone VAL 7, pumped from 815 Zone Zone VAL 7, pumped from 877 Zone Zone VAL 7, reduced from 1530 Zone () Zone VAL 7, reduced from 1530 Zone () Zone (Coronado Hills) VAL 10 and VAL 9, pumped from 90 Zone () Double Peak Zone VAL 7, pumped from 1115 Zone () Pressure Zone HGLs are based on the bottom elevation of the tank serving the zone or the setting of the PRV. The 1530 Zone is currently operated as two separate systems via a closed valve to maximize water quality. Once Double Peak builds out and more demand is brought online, the pressure zones may be operated together. 5-4 Vallecitos Water District Master Plan

5 5.1.3 Pump Stations The District currently operates nine pump stations (including the Meadowlark Hydropneumatic Pump Station), all feeding directly to storage tanks in the system. Table 5-3 summarizes the hydraulic grade line (HGL), the number of pumps, rated capacity and operational capacity at each existing pump station within the District. The operational capacity is defined as the capacity of the pump station with the largest pump out of service. Most of the District s pump stations cannot realize their total capacity due to physical constraints, such as insufficient transmission pipeline capacity Reservoirs Reservoirs serve four critical water storage needs: operational storage for daily use; fire flow storage; and both in-zone emergency storage and storage during aqueduct shutdowns, as previously defined in Chapter 3. The District operates and maintains 0 potable water reservoirs, which are listed in Table 5-4. This table includes the size, age, and HGL for each reservoir. The total existing storage capacity for the District s potable water system is 11.6 million gallons (MG) System Control Valves The District currently operates 7 Pressure Regulating Stations (PRSs), 1 altitude control valve, and 3 Flow Control Facilities (FCFs) within the District. Table 5-5 summarizes the District s system control valves with station elevations, valve diameters, and valve settings. In general, the PRSs allow water to flow from an upper zone into a lower zone by reducing the pressure through a globe style valve based on downstream pressure control. The altitude control valve located at the 18 North Reservoir controls the flow into the North Reservoir based on a downstream pressure setting. The Trussell and Mulberry PRSs also operate as FCFs, The North Twin Oaks Pump Station is located at the Twin Oaks reservoir site, and pump water from the reservoirs to the North Twin Oaks 1330 Zone. The 877 Reservoir and the 1115 Pump Station serve new development in San Elijo Hills. The reservoir helps regulate flows from VAL-7 in the 877 Zone. which provide higher flows from the District s transmission system. These valves are operated remotely by changing the pressure set points to provide higher flows into the Richland 90 Zone from the 108 Zone, which also allows for better cycling of the 90 Reservoirs. Similarly the Meadowlark FCF allows flow from the 877 Zone into the 815 Zone. The Trussell Flow Control valves (left) and pressure reducing valves (right) are in a common vault along Twin Oaks Valley Road. The valves each reduce water from the 108 Zone to the 90 Zone, however, the flow control valves provide higher flows to a transmission system and the reducing valves serve more localized distribution systems. 5-5 Vallecitos Water District Master Plan

6 Table 5-3 Existing Pump Station Summary Pump Station Northern Pump Stations Deer Springs North Twin Oaks Wulff Coggan Central Pump Stations Palos Vista South Lake Southern Pump Stations Meadowlark Hydro HGL Rated Capacity Total Capacity Operational Capacity (1) From To Pump Unit gpm MGD gpm MGD gpm MGD Schoolhouse Double Peak (1) , , , ,000.88, , , , , , , , , (Fire) 1, , , , Operational capacity is the total capacity of the station less the largest pump unit., , , , , , , , , , , , , , , , , Vallecitos Water District Master Plan

7 Table 5-4 Existing Reservoir Summary HGL (1) Pressure Zone Northern Reservoirs Name Facility ID (Name) Year Built Material Height (ft) Diameter (ft) Capacity (MG) 900 Tres Amigos Mountain Belle 1996 Steel Twin Oaks Twin Oaks Reservoir #1 000 Concrete Twin Oaks Reservoir # 007 Concrete Subtotal 108 Pressure Zone North 18 North 1977 Steel Deer Springs Deer Spring 1961 Steel North Twin Oaks North Twin Oaks Reservoir #1 North Twin Oaks Reservoir # 1961 Steel Steel Subtotal 1330 Pressure Zone Wulff Wulff 1961 Steel Coggan Coggan 1977 Steel Central Reservoirs 90 Richland Total North 8.9 Richland # Steel Richland # 1981 Steel Palomar 1989 Steel Via Vera Cruz 1987 Steel Subtotal 90 Pressure Zone Palos Vista Palos Vista 1991 Steel Southern Reservoirs 815 Meadowlark Total Central.0 Meadowlark # Steel Meadowlark # 1979 Steel Subtotal 815 Pressure Zone Las Posas Sage Canyon 001 Steel Schoolhouse 001 Steel () Coronado Hills Coronado Hills 1981 Steel Double Peak 006 Steel Subtotal 1530 Pressure Zone 6.4 Total South 16.6 Total 11.6 Source Data: VWD 007 Operational Data (1) Hydraulic Grade Line (HGL) for the District is defined as the base elevation of the reservoir. () The 1530 Zone is currently operated separately via a closed valve to maximize water quality. Once the Double Peak PZ builds out and more demand is brought online, the PZs may be operated together. 5-7 Vallecitos Water District Master Plan

8 Table 5-5 Existing System Control Valves Station Name Type of Valve Downstream Pressure Zone Northern Pressure Reducing Stations (1) Mulberry FCF Richland (90) La Cienega North North Tank PRS Richland (90) PRS Altitude Control Mountain Belle (900) North (18) South PRS 1059 Zone Trussell Upstream Pressure Zone Twin Oaks (108) Twin Oaks (108) Number of Valves 1059 Zone Coggan (1608) North Twin Oaks (1330) FCF Twin Oaks Richland (90) (108) PRS Central Pressure Reducing Stations (1) Barham PRS 855 Zone Craven PRS 855 Zone McMahr PRS 855 Zone Pacific PRS 855 Zone Town Center PRS 855 Zone Village R PRS 115 Woodland Valley Summit Circle Woodland Heights PRS PRS PRS 105 Zone 1380 Zone 1380 Zone Southern Pressure Reducing Stations (1) Melrose PRS 664 Zone Alga Road PRS 686 Zone Richland (90) Richland (90) Vera Cruz (90) Palomar (90) Richland (90) Coronado Hills (1530) Palos Vista (1500) Palos Vista (1500) Palos Vista (1500) Meadowlark (815) Meadowlark (815) Valve Size (in) Elevation (ft) Hydraulic Grade Setting (ft) Pressure Setting (psi) , Vallecitos Water District Master Plan

9 Table 5-5. Continued Station Name Type of Valve Downstream Pressure Zone Corintia PRS 664 Zone Fallsview PRS 750 Zone La Costa Meadows La Costa Oaks La Costa Ridge PRS PRS PRS La Costa Meadows (6) 750 Zone 670 Zone Northstar PRS 750 Zone Meadowlark Paseo Frontera FCF PRS Meadowlark (815) 670 Zone Wild Canyon PRS 130 RSF & Melrose PRS 6 Zone Eclipse PRS 130 Xana Way PRS 670 Zone (1) Upstream Pressure Zone Meadowlark (815) Sage Canyon (877) Meadowlark (815) Sage Canyon (877) Meadowlark (815) Sage Canyon (877) Sage Canyon (877) Meadowlark (815) 1530 Double Peak Meadowlark (815) 1530 Double Peak Meadowlark (815) Number of Valves Valve Size (in) Potable Water Distribution System Elevation (ft) Hydraulic Grade Setting (ft) Pressure Setting (psi) Pressure reducing stations are identified as Northern, Central, or Southern based on the upstream pressure zone Distribution System Pipelines The District maintains over 345 miles of water mains ranging in size from 4-inches to 48-inches in diameter. Table 5-6 includes an inventory of material types, sizes and range of age by material. In general, the pipelines are predominantly asbestos cement pipe (ACP) and ductile iron pipe (DIP). As shown in Table 5-6, the majority of the District s system has been installed since the 1960s and thus should have many years of remaining functionality based on the expected useful life of the pipe materials. 5-9 Vallecitos Water District Master Plan

10 Table 5-6 Water Distribution Pipeline Inventory Pipe Type Lineal Diameter Pipe Length by Decade Feet Min Max Unknown 1950s 1960s 1970s 1980s 1990s 000s ACP 937, ,08 151, ,154 3,65 41,487,913 DIP 500, , , ,04 Steel, Cement Mortar Lined and Coated Steel, Cement spiralwrapped 380, ,804 59,675 49,615 6,75 119,450 56,545 6, , Total 1,84, , ,039 11,514 39,769 95,40 384, , Interagency Service Agreements The District provides potable water to OMWD and Carlsbad MWD from its Water Authority connection at VAL 7 via the Questhaven Pipeline. This service is provided through an interagency service agreement entitled Construction of a Water Transmission and Storage System Questhaven Pipeline dated July 1, 1978 and its supplement dated September 1979, in which the District is designated as the lead agency. The following paragraphs summarize the conditions of this agreement with each agency. The locations of these interconnections are numbered 1 and 4, as shown on Figure 5-. The OMWD capacity by agreement is limited to 6.47 MGD. The corresponding OMWD pressure zone, served by the Questhaven Pipeline, is the 83 Zone. In 007, OMWD received an average of 0.9 MGD through this connection. The Carlsbad MWD connection capacity by agreement is limited to 8.61 MGD. Carlsbad MWD is supplied via a flow control facility from the District s 815 Meadowlark Zone, which is supplied from the District s 877 Zone via a pressure reducing station. The Alga Road flow control facility serving Carlsbad MWD consists of two 10-inch diameter flow control valves. The corresponding Carlsbad MWD pressure zone served by the Questhaven Pipeline is the 77 La Costa Hi Zone, served by the La Costa Hi Reservoir. In 007, Carlsbad MWD received an average of.5 MGD through this connection Emergency Connections Of the 15 inter-agency service connections to neighboring water districts, 13 of them are solely available to the District under emergency conditions. The District has emergency connections with the City of Carlsbad (1), Vista Irrigation District (8), the City of Escondido (1), Rincon del Diablo Municipal Water District (1), Rainbow Water District (1), and Olivenhain Municipal Water For Construction of a Water Transmission and Storage System Questhaven Pipeline Agreement, dated July 1, 1978 and supplement, see Technical Memorandum No. 4, Appendix D Vallecitos Water District Master Plan

11 Ä 13 RAINBOW!(!( 7 ORMSBY NORTH COUNTY DISTRIBUTION PIPELINE Gopher Canyon Rd Rainbow WD Old Castle Rd Valley Center WD!"a$ FIRST AQUEDUCT Vista Irrigation District SECOND AQUEDUCT A CROSSOVER PIPELINE Buena Creek Rd Deer Springs Rd TRI-AGENCIES PIPELINE LINDA VISTA/VID 10!( Carlsbad MWD Melrose Ave CMWD!( 1 CAPALINA S SANTA FE/VID!(!( 1 11 Rancho Santa Fe Rd!( MELROSE/CARLSBAD Mission Rd San Marcos Blvd Twin Oaks Valley Rd 9 MULBERRY!(!( 8 REES & EL NORTE VID ESCONDIDO PUMP 3!( 14 NORDAHL!(!( 15 KNOBHILL/ CENTER ST 6!( RINCON DEL DIABLO Escondido MWD Legend!( Alga Rd VWD Sphere of Influence VWD Service Area SDCWA Suppy Pipeline Interconnect Point 4 5 OMWD!(!( SAN ELIJO HILLS PUMP OMWD Questhaven MWD Rincon del Diablo WD Ü Miles SOURCE: LAFCO SOI - Affirmed VWD GIS Data , provided by District 10/6/010 KC SD Z:\Projects\IS\VallecitosWaterDistrict\007MasterPlan\mxd\Interconnects_Fig5-.mxd INTER-AGENCY AND EMERGENCY SERVICE CONNECTIONS FIGURE 5- Vallecitos Water District Master Plan

12 District (1), as shown on Figure 5-3. These connections are limited in their ability to deliver flows, and would be used for short term outages within the District or the neighboring agency. With the improved reliability of the regional system following the implementation of the Emergency Supply Project and the anticipated delivery of desalinated water to the District, as discussed in Chapter 4, there is no immediate need to supplement or increase the capacity of the existing connections. Table 5-7 Emergency Interagency Connections Reference & Location (see Figure 5-) Name Size (in) System Service to Connecting Agency Pressure Zone Approx. Flow Rate (gpm) Melrose/Carlsbad Crosstie 8 VWD CMWD Escondido Pump Connection 8 EWD VWD 90 1,000 5 San Elijo Hills Pump Connection 8 OMWD VWD 877,000 6 Rincon del Diablo Crosstie 8 VWD Rincon Rainbow Crosstie 8 VWD RMWD 900 1,800 8 Rees & El Norte VID Crosstie 8 VWD/VID VID/VWD Mulberry Crosstie 6 VWD VID Linda Vista/VID Crosstie (Stone Gate PRV) 6 VWD VID S. Santa Fe Crosstie 8 VWD VID Capalina Crosstie 8 VWD VID Ormsby Crosstie 8 VWD VID Nordahl Crosstie 1 VWD VID 90 N/A 15 Knobhill/Center St Crosstie N/A VWD VID 90 N/A 5. Water Demands This section summarizes the historical delivery of water from the Water Authority, as well as existing and projected future water demands Historical Water Deliveries The District orders potable water through the Water Authority up to two times a day, depending on system demands and reservoir levels. The deliveries from the Water Authority are recorded at each of the five connections to the District s potable water transmission system. The District s average delivery and maximum month water delivery, expressed in MGD, during the calendar years 00 through 007 are presented in Table 5-8 and the annual trends are graphically represented in Figure For VWD Intertie Data, see Technical Memorandum No. 4, Appendix A. 5-1 Vallecitos Water District Master Plan

13 Year Table 5-8 Water Authority Deliveries 4 Total Average Annual Delivery (1) (MGD) Percent Change in Average Annual Delivery Potable Water Distribution System Maximum Month Delivery (MGD) Maximum Month to Average Annual Ratio % % % % % Overall growth since % Source Data: VWD Operational Delivery Log Sheets, as recorded by District staff (1) Average Annual Delivery does not include pass-through flows for Carlsbad MWD and OMWD Figure 5-3 Water Authority Delivery Trends Figure 5-4 displays the monthly potable water deliveries for 007. Using the 007 data, the District received approximately 30 percent more water than average during the month of August (typically the maximum month period), and during the minimum month of December, the District received approximately 55 percent of the average annual delivery. As expected, residential (which includes residential landscape uses) and irrigation water demands vary seasonally with higher demands in the hotter summer months and lower demands in the winter months. 4 For VWD Operational Data, see Technical Memorandum No. 4, Appendix B Vallecitos Water District Master Plan

14 Delivery (MGD) Potable Water Distribution System Figure Monthly Water Authority Deliveries Avg Delivery = 19.1 MGD Source: VWD Operational Data, recorded by District staff. 5.. Existing Demands Current water use in the District was evaluated by examining the monthly meter sales records from January through December 007. A total of 1,816 water meters were identified within the database. According to the 007 billing data, the District experienced an average day demand of approximately 18.3 MGD. Using the historical data provided by the District, the maximum month to average day ratio over the previous six years is approximately 1.4. Table 5-9 presents the average day demand (ADD) by pressure zone for 007. Pass-through flows serving OMWD and Carlsbad MWD are not included in Table 5-9. It should be noted that the ADD includes water consumption through temporary meters, but does not include other end delivery facilities that are typically unbilled uses such as fire hydrant testing or system flushing. Unbilled water is the difference between the total Water Authority delivered water (19.1 MGD) and the total amount billed by the District to its customers (18.3 MGD). Generally unbilled water is associated with leaks, pipeline breaks, older meters that are not correctly calibrated, system flushing, and unmetered hydrant uses such as firefighting and illegal construction water usage. Annual unbilled water loss for 007 is estimated to be 309 MG, which represents approximately 4.4 percent of the total water purchased from the Water Authority by the District. The 00 Master Plan documented water loss for the District at 3 to 8 percent over the past sixteen years, a trend that has continued since 00. These factors are consistent with industry standard losses. Unbilled water data since 00 is presented in Table Vallecitos Water District Master Plan

15 Table Potable Water Metered Demands by Pressure Zone 5 Pressure Zone Average Day Demand (ADD) HGL Name (gpm) (MGD) Northern Pressure Zones 900 Tres Amigos Twin Oaks Zone North Deer Springs North Twin Oaks Wulff Coggan Total Northern Zones 1, Central Pressure Zones Zone 3, Richland 4, Zone Zone Palos Vista Total Central Zones 8, Southern Pressure Zones 6 La Costa La Costa Ridge / Melrose Zone Alga Zone Meadowlark Las Posas Meadowlark Hydro Zone Zone Zone Coronado Hills Double Peak Total Southern Zones, Total 1, For detailed demand information, see hydraulic model in Technical Memorandum No. 4, Appendix C Vallecitos Water District Master Plan

16 Year Annual SDCWA Delivery (MG) Table 5-10 Unbilled Water Summary 6 Annual Water Sales (MG) Change in Storage (MG) Potable Water Distribution System Unbilled Water (MG) % Annual Unbilled Water 00 5,95 5, % 003 5,85 5,469 (4.1) % 004 6,98 5,917 (0.) % 005 6,331 5, % 006 6,535 6,06 (7.4) % 007 6,969 6, % The District serves a predominantly residential community, where nearly 61 percent of the water use is single-family and multi-family residential. A majority of the water use is for residential (including residential landscape irrigation uses) and outdoor uses, such as community landscape irrigation. Figure 5-5 summarizes the demands by meter type. Figure Potable Water Demands by Meter Type 5..3 Future Water Demands Water demand projections were developed for the planning horizon year 030 (030). The following steps were utilized in developing the future water demands: The planned land use coverage was provided to the land use agencies for comment and the land use agencies provided their approved zoning maps and comments to the planned land use, as discussed in Chapter. 6 For unbilled water data, see Technical Memorandum No. 4, Appendix B Vallecitos Water District Master Plan

17 All parcels were attributed with their approved zoning. Approved redevelopment projects were then identified as discussed in Chapter. The land use database now represents the ultimate land use condition with the maximum potential development of existing and future parcels. Working with the District, Vacant and Not Served parcels were assigned likely connection points to the existing distribution system or were determined to be best served by an exchange agreement. 7 Ultimate demand projections were then estimated by applying the appropriate unit demands, developed in Chapter 3, to all parcels identified as being served by VWD, or another agency through an exchange agreement. The demands were then updated for approved redevelopment projects identified in Chapter, per the most recent Water Studies provided to the District. 8 Future demands for existing parcels currently assigned a metered demand were projected based on the ultimate land use and unit water demand. The actual existing metered demands were not used in future demand projections. 030 Demand Projections were developed by applying the SANDAG 030 Planned Land Uses coverage to the Ultimate Demand Projections, as described in Chapter. Projected Future Water Demands Table 5-11 presents the existing and projected future average water demands for the District at 5-year increments up to 030 and ultimate build-out conditions. Projected water demands for interim years 010, 015, 00, and 05 were estimated based upon SANDAG s growth forecasts for VWD, described in Chapter. A comparison between the 008 Master Plan and 00 Master Plan ADD projections is included in Table The new ultimate water demand projection for the District is approximately 34.1 MGD, which is higher than the 31.9 predicted in the 00 Master Plan by. MGD. The 030 planning horizon projected demands are estimated at 31. MGD, which is 8.1 MGD higher than the 3.1 MGD projected by the 00 Master Plan. The difference is largely attributed to the assumption that all non-vacant parcels will be developed at their approved zoning by 030. In addition, slightly higher unit demand criteria for some land uses, as discussed in Chapter 3, contributes to this higher water demand projection. Table 5-1 presents the projected ADD for each pressure zone within the District through For working maps of Vacant and Not-Served parcels, see Technical Memorandum No. 3, Appendix M. For the Redevelopment Water Studies, see Technical Memorandum No. 4, Appendix E Vallecitos Water District Master Plan

18 Table 5-11 Demand Projection Comparison 9 Potable Water Distribution System (1) Year 00 Master Plan Projected ADD (MGD) 008 Master Plan ADD (MGD) Projected Annual Increase (%) Existing, 007 (1) % % % % % Ultimate % Based on District billing data for January through December 007 Table 5-1 Interim Year Demand Projections by Pressure Zone Pressure Zone Existing and Projected Average Day Demand (MGD) HGL Name Existing (007) La Costa La Costa Ridge / Melrose Zone Alga Zone Meadowlark Zone Las Posas Tres Amigos Richland Meadowlark Hydro Twin Oaks Zone Zone Zone Zone North Deer Springs Zone North Twin Oaks Zone Palos Vista Coronado Hills Double Peak Wulff Coggan Total For the Projected Future Water Demand data, see Technical Memorandum No. 4, Appendix F Vallecitos Water District Master Plan

19 5.3 Hydraulic Model Development A hydraulic water system model was developed to analyze the existing and future potable water system, which included pipelines, reservoirs, pump stations, and PRSs. Existing (007) water demands were input into the model by the District based on actual water usage for the existing system. This section describes the water model development and model calibration Existing System Hydraulic Model Development Detailed hydraulic models are required in order to analyze the complex operation of the District s water system. The steps of model formulation include obtaining the system s physical data, translating the physical data into a network of nodes and links, determining pressure zone boundaries, inputting accurate water demands, and calibrating the model to match the District s operational field data. A new hydraulic WaterGEMS model was initially developed by the District for the potable water system using the District s GIS database as the source information for pipes, junctions, valves, pumps and tanks. The existing potable water hydraulic model is based on the District s GIS updates as of September 007. Relevant information such as diameter, length, material, installation year, pressure zone, and reference drawing number was included in the model and entered manually, where necessary, for all facilities if the data was available. Node elevations were obtained from as-built drawings. Storage tanks were annotated with capacity, high water level (HWL), diameter, and height. Pressure reducing valve set points, pump station controls, and other operational settings were obtained from District engineering and operations staff through workshops and detailed review of computerized system operational data information. The locations of closed valves were also confirmed and identified in the model. Demands were distributed throughout the system by assigning demands for each parcel to a model node. In summary, the District provided a static base model which included relevant infrastructure, existing demands, and operational settings for calibration and analysis of the existing and future water systems. No future facilities were identified in the District-provided model. The hydraulic software WaterGEMS was utilized for the model development and analysis of the District s system. This software has the capability to interface directly with GIS data in order to create the necessary facilities for the model. All relevant information was linked directly to the GIS, rather than having to digitize and manually input. In addition, this software allows for efficient future model updates from GIS data as the District continues to build out. Training of District personnel is essential to maintaining the GIS and hydraulic models Model Calibration Once the existing hydraulic model was developed, a macro calibration approach was performed, which compares field data over an extended period of time to the model output. The first stage to developing a macro-calibrated model is to obtain current Supervisory Control and Data Acquisition (SCADA) information from the District for a selected time period. This real-time field data 10, such as reservoir trends, Water Authority water deliveries, and pump station flows, was collected over a 3-day period from September 5 through September 7, 007. This period included the peak day on the maximum demand month for the 007 calendar year. Reservoir 10 For District SCADA data and calibration results, see Technical Memorandum No. 4, Appendix G Vallecitos Water District Master Plan

20 levels and pump station operations were analyzed to determine a general diurnal pattern within the District. Figure 5-6 presents the average day diurnal pattern developed for the District. On an average day, the minimum demand is approximately half of the average day demand. The maximum day diurnal pattern was developed using the peaking curves presented in Figure 3-1 to determine a District-wide maximum day peaking factor of 1.9. This peaking factor was then applied to the average daily diurnal pattern to determine the maximum day pattern, as shown in Figure 5-6. The peak hour factor that occurs on a maximum day is approximately 3.0. Figure 5-6 Time of Day Diurnal Pattern Diurnal demand patterns and initial tank levels were then input into the hydraulic model to determine an analytical baseline. During macro calibration it is possible to find areas that require further analysis, in which case special equipment can be set up in the field to test flows and pressures at different times. This process can often identify problem areas in the field, such as partially closed valves or other areas of concern. For this 008 Master Plan, no additional field analysis was performed. The availability of SCADA data and knowledge of Operations staff was utilized to macro-calibrate the model to a reasonable level of confidence For level of confidence ratings and discussion, see Technical Memorandum No. 4, Appendix J. 5-0 Vallecitos Water District Master Plan

21 System Computer Model Development The 030 model of the District was based on the calibrated existing system, demands projected in Section 5., projects currently in various levels of design and construction, and the completion of necessary CIP Projects. The need for these CIP projects and their timing were verified using the hydraulic model, input from District staff, and knowledge of planned development timing. 5.4 Water System Analysis This section presents the potable water system capacity analysis and identifies any deficiencies in the existing water storage and pumping systems. In addition, future analyses were conducted to identify phased CIP projects. Specific phases have been developed to be able to forecast, plan and budget for anticipated growth within the District. The existing system is defined as Phase 1, which includes those projects currently in design or construction, or anticipated to be built by 010. Table 5-13 shows the different phasing stages. Table 5-13 CIP Phasing Planning Years Phase Planning Years A hydraulic profile of the District s potable water system is provided in Figure 5-7. This figure illustrates how the different pressure zones are interrelated under existing conditions Water System Analysis Existing The calibrated model, based on September 007 maximum day demands, was used to analyze the District s existing system to determine areas of deficiencies based on District planning criteria. The results of the maximum day analysis show that the District s system has sufficient transmission and pumping capacity to serve existing demands and replenish operational storage. Total operational storage and pumping requirements are calculated based on the planning criteria outlined in Chapter 3 and are presented in the following section. Storage Analysis (Operational and Emergency) Table 5-14 presents the reservoir storage balance calculations for the operational storage required for existing demands in each pressure zone. The storage calculations for supplying primary pressure zones include the secondary pressure zone demands served by pressure reducing stations and hydropneumatic pump stations. 5-1 Vallecitos Water District Master Plan

22 The storage analysis shows that several pressure zones have in-zone storage deficiencies. The District allows existing deficiencies to be mitigated by excess storage in a neighboring connected zone that can serve the deficit zone. For example the 1530 Double Peak Zone has a surplus in storage that can offset the deficit in the 877 and 1115 Zones. However, there is no neighboring zone that can offset the deficit in Deer Springs and Wulff Reservoirs in the 135 and 1567 Zones, respectively. Under existing conditions, the deficit in the Meadowlark Reservoir in the 815 Zone can be offset via the 108 Zone, if a normally closed valve is opened. The remaining pressure zones within the District have adequate storage capacity to meet existing demands and storage criteria. Overall, the District has a net surplus storage volume of MG as shown on Table 5-14, the majority of which is in the 108 Twin Oaks Reservoirs. Emergency storage capacity was also analyzed using the criteria set forth in Chapter 3, Table 3-3, of five average days of storage. The analysis determined that, as a whole, the existing District system has adequate emergency storage of 9.83 MG with a surplus of 8.76 MG. Pump Station Capacity Analysis (Existing System) Capacity requirements are based on the planning criteria as discussed in Chapter 3, Table 3-3. The pumping calculations for supplying primary pressure zones are cumulative and include demands for the direct pumped zone and all zones above. Table 5-15 presents the pump station capacity analysis for the existing system. As shown in Table 5-15, the existing pump stations have adequate capacity to meet existing system conditions. No pump station upgrades are required to maintain existing demand requirements. An off-peak analysis of the existing pump stations was performed to determine the ability of the existing pump stations to deliver maximum day demands over a 16 hour period. Off peak pumping allows the District to avoid the higher energy costs associated with operating during peak energy use hours. Table 5-16 indicates a deficit in pump capacity in the 1567 Wulff PS. This pressure zone is anticipated to have a reduced ADD over the coming years which may allow this pump station to operate off peak without improvements, so no improvements are recommended at this time. Off peak pumping during the maximum day demands at the 135 Deer Springs PS may also result in a deficit pump capacity. Upsizing should be considered when these pumps reach the end of their useful lives. 5- Vallecitos Water District Master Plan

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25 Table 5-14 Existing Storage Analysis Primary Zone Zone(s) Served 815 Pressure Zone Reservoir Name Storage Capacity (MG) Meadowlark #1 1.6 Meadowlark #.71 Existing ADD (MGD) Required Storage per Design Criteria (MG) Operational (1.5 x ADD) Fire Emergency (3.0 x ADD) Total 4.5 ADD + Fire 664 (No storage) (No storage) (No storage) (No storage) Total 5.0 x ADD 815 Total Sage Canyon (No storage) (No storage) Total Required Storage by Zone (1) (MG) Surplus (Deficit) (MG) 5.14 (1.17) 6.49 (.77) Mountain Belle Twin Oaks Reservoir # Twin Oaks Reservoir # (No storage) Richland Reservoir #1 1.6 Richland Reservoir # 7.05 Palomar Reservoir.71 Via Vera Cruz Reservoir Total Schoolhouse (0.4) North Deer Springs (1.4) 5-5 Vallecitos Water District Master Plan

26 Table Continued Primary Zone Zone(s) Served 1330 Pressure Zone Reservoir Name Storage Capacity (MG) North Twin Oaks # North Twin Oaks # 3.60 Existing ADD (MGD) Required Storage per Design Criteria (MG) Operational (1.5 x ADD) Fire 0.30 Emergency (3.0 x ADD) 0.81 Total 4.5 ADD + Fire 1059 (No storage) Total 5.0 x ADD 1330 Total Palos Vista (No storage) (No storage) Total Coronado Hills () 115 (No storage) Coronado Hills Total Double Peak () 130 (No storage) (1) () 1530 Double Peak Total Required Storage by Zone (1) (MG) Surplus (Deficit) (MG) Wulff (.01) Coggan District Total The required storage for each zone is the greater of 4.5 ADD + Fire OR 5.0 ADD. The 1530 Zone is currently operated as two separate zones through a normally-closed valve. 5-6 Vallecitos Water District Master Plan

27 Table 5-15 Existing Pump Station Capacity Analysis Pump Station Northern Pump Stations Includes Capacity for Zones Existing ADD (gpm) Max Day Peaking Factor Max Day Demand (gpm) Max Day + Fire Recharge (1) (gpm) Operational Capacity (gpm) Surplus/ (Deficit) (gpm) 135 Deer Springs 135, ,340 1,490 1, N. Twin Oaks 1330, ,000 1, Wulff , Coggan 1608, ,000 3,316 Central Pump Stations 1500 Palos Vista 1500, 1380, ,034 3,375,341 Southern Pump Stations Meadowlark Hydro () Schoolhouse 1530 Southlake 1530 Double Peak (1) () 1115, 1530 Double Peak, Coronado Hills, Double Peak, ,4 1,374, ,00 1, , Fire recharge estimated at 150 gpm per Table 3-3. Meadowlark Hydropneumatic Pump Station has a separate fire pump, and no fire storage within the hydropneumatic tank; therefore, fire recharge is not needed. Table 5-16 Existing Pump Station Off-Peak Pumping Analysis Pump Station Northern Pump Stations Includes Capacity for Zones Existing ADD (gpm) Max Day Peaking Factor Max Day + Fire Recharge (gpm) Max Day Demand for 16 hour off peak pump period (gpm) Operational Capacity (gpm) Surplus/ Deficit for Off Peak Pumping (gpm) 135 Deer Springs 135, ,490,34 1,550 (684) 1330 N. Twin Oaks 1330, ,, Wulff ,371 1,000 (371) 1608 Coggan 1608, ,05 4,000,975 Central Pump Stations 1500 Palos Vista 1500, 1380, ,034 1,550 3,375 1,85 Southern Pump Stations Meadowlark (1) NA Hydro 1115 Schoolhouse 1530 Southlake 1530 Double Peak (1) 1115, 1530 Double Peak, Coronado Hills, Double Peak, 130 Meadowlark Hydropneumatic Pump Station cannot operate off-peak ,374,061, ,410, , Vallecitos Water District Master Plan

28 5.4. Water System Analysis 030 The 030 water system was analyzed based on projected demands for the District, which increase to an ADD of 31. MGD in 030, as shown in Table These demands were used to analyze the storage and pumping facilities and pipelines within the District. Storage Analysis (030 System) Table 5-17 presents the 030 storage analysis. The District currently has 11.6 MG of potable water storage and, based on future demand projections, will require MG of storage by 030. The analysis indicated that each pressure zone has storage deficiencies in 030. The proposed capacities of new reservoirs were calculated to offset these deficiencies. In some cases the new reservoir will replace an aging reservoir. The new or replacement reservoirs are shown in bold in Table 5-17 and include the following: 815 Meadowlark #3.80 MG Demolition of 1.6 MG Meadowlark #1 815 Meadowlark # MG 108 Twin Oaks # MG 135 Deer Springs # 1.00 MG Demolition of 0.57 MG Deer Springs # North Twin Oaks # MG Demolition of 0.57 MG North Twin Oaks # Palos Vista #1 Rehab 0.5 MG add 0.5 MG to existing 3.96 MG reservoir 1530 Coronado Hills # 4.73 MG 1530 Coronado Hills #3 3.1 MG 1567 Wulff # 0.35 MG Demolition of 0.10 MG Wulff # Coggan # 6.00 MG Demolition of 1.30 MG North Reservoir 1608 Coggan # MG Consideration was made for zones that did not have an adequate site that would allow the District to add or expand a reservoir. For example, there is no room at the 877 Sage Canyon Reservoir site or the 1115 Schoolhouse Reservoir site to add a second reservoir. Therefore, the storage deficiency in these zones is accommodated in the new 1530 Coronado Hills # Reservoir. The North Twin Oaks Reservoir #3 is planned to mirror the existing #, and therefore is being planned for 3.6 MG in capacity. With the demolition of North Twin Oaks #1, the deficit is covered in the 108 Twin Oaks Zone. The 900 Mountain Belle Reservoir deficit is also accommodated in the new 108 Twin Oaks Reservoir. The demolition and replacement of the Wulff and Deer Springs Reservoirs is constrained due to available site conditions, so the deficit storage in these zones is accommodated in the 108 Twin Oaks Zone. The demolition of the 18 North Reservoir leaves a deficit of 1.63 MG which will be accommodated in the new 1608 Coggan Reservoirs. As a whole, the 030 District system has sufficient emergency storage of MG with the expanded reservoir capacity, as listed in Table Vallecitos Water District Master Plan

29 Primary Zone Zone(s) Served Pressure Zone Reservoir Name Storage Capacity (MG) Table 5-17 Storage Analysis ADD (MGD) Required Storage per Design Criteria (MG) Operational (1.5 x ADD) Fire Emergency (3.0 x ADD) Total 4.5 ADD + Fire Total 5.0 x ADD Required Storage by Zone (1) (MG) Surplus (Deficit) (MG) Meadowlark #1 () Meadowlark #.71 Meadowlark # Meadowlark # (No storage) (No storage) (No storage) (No storage) Total Sage Canyon (No storage) (No storage) (4.10) 877 Total Mountain Belle (1.9) 108 Twin Oaks Reservoir # Twin Oaks Reservoir # Twin Oaks Reservoir # (No storage) Richland Reservoir # Richland Reservoir # 7.05 Palomar Reservoir Via Vera Cruz Reservoir Total Schoolhouse # (0.63) North () (1.63) Deer Springs #1 () (.94) Deer Springs # Vallecitos Water District Master Plan