Task 3: Recycled Water Distribution System Master Plan Cambria Community Services District Cambria, California July 2004 K/J

Transcription

1 FINAL REPORT Task 3: Recycled Water Distribution System Master Plan Cambria Community Services District Cambria, California July 2004 K/J

2 Table of Contents List of Tables... iii List of Figures... iv List of Appendices... iv List of Abbreviations... v Executive Summary...ES-1 Section 1: Introduction Background Objectives Scope of Services Conduct of the Study...3 Section 2: Recycled Water Supply and Demand Projections Recycled Water Supply Projected Recycled Water Demand Potential Recycled Water Users Potential Recycled Water Demand Peaking Factors Average Daily Demand Seasonal Storage Opportunities Seasonal Supply and Demand Balance No Net Change Concept Above Ground Seasonal Storage Subterranean Storage in the San Simeon Basin...15 Section 3: Regulatory Requirements Federal Requirements Clean Water Act Safe Drinking Water Act Endangered Species Act Compliance Administration State Requirements Water Code Title Title Guidelines Emerging Recycled Water Quality Concerns N-Nitrosodimethylamine (NDMA) ,4 Dioxane Trace Pharmaceuticals...22 Final Report Task 3: Recycled Water Distribution System Master Plan Page i

3 Table of Contents (cont'd) Section 4: Treatment Processes Title 22 Requirements Potential Additional Processes Dentrification Nanofiltration (low pressure reverse osmosis) Advanced Oxidation (hydrogen peroxide and ultraviolet light irradiation)...24 Section 5: Development of the Recycled Water System Recycled Water System Model Guidelines Recycled Water Demand Scenarios Recycled Water System Model Development Recycled Water Distribution System Pipelines Storage Tanks...27 Section 6: Results of the Recycled Water System Analyses Evaluation Criteria Pipelines Recycled Water Distribution System Storage Tanks Operational Storage Fire Storage Pump Stations Critical Conditions for Modeling Results of Hydraulic Analyses Peak Hour Demand for Recycled Water System Commercial Fires During Maximum Day Demand Storage Tanks Pump Stations...33 Section 7: Recommended Recycled Water System Basis for Evaluation of Recommended Improvements Basis of Preliminary Cost Estimates Treatment Plant Improvements Pipelines Storage Tanks Pump Stations Recommended Recycled Water System Pipelines Recommended Storage Operational Storage Seasonal Storage Recommended Pump Stations Improvements...39 Final Report Task 3: Recycled Water Distribution System Master Plan Page ii

4 Table of Contents (cont'd) 7.6 Estimated Recycled Water System Costs...39 Section 8: Recommended Implementation Plan Implementation Considerations Phasing Plan Implementation Schedule...42 List of Tables 2-1 Potential Recycled Water Users 2-2 Estimated Irrigation Demand for CCSD using a Conventional System 2-3 Estimated Irrigation Demand for CCSD using an ECS System 2-4 Maximum Day and Peak Hour Factors 2-5 Projected Recycled Water Demand (AFY) 2-6 Projected Recycled Water Demand vs. Supply 2-7 Basin Demand Balance 6-1 Evaluation of Tank Storage 6-2 Evaluation of Pumping Capacity 7-1 Treatment Plant Improvements 7-2 Pipeline Unit Costs (mid-2002 dollars) 7-3 Reservoir Unit Costs 7-4 Pump Station Unit Costs 7-5 Proposed Pipeline Costs 7-6 Estimated Reservoir Costs 7-7 Estimated Pump Station Costs 7-8 Estimated O&M Costs (2002) for Recycled Water Final Report Task 3: Recycled Water Distribution System Master Plan Page iii

5 Table of Contents (cont'd) List of Figures 2-1 Seawater Intrusion Concept for CCSD 2-2 Potential Recycled Water Users 2-3 Recycled Water Demand vs. Supply 2-4 Location of Proposed Subterranean Storage 3-1 Understanding Recycled Water Regulations 5-1 Proposed Recycled Water System 8-1 Implementation Schedule List of Appendices A Evaporative Control Systems, Inc. (ECS) Information B Summary of Water Demand Data C Summary of Pipeline Sizes and Lengths D Model Results E Breakdown of Pipeline Costs Final Report Task 3: Recycled Water Distribution System Master Plan Page iv

6 Table of Contents (cont'd) List of Abbreviations USACE AF AFY AWWA CCSD CWA DHS ECS ENR ESA Ft/s GIS gpd gpm MBR MCL MG MGD MtBE NDMA NMFS NPDES psi RO RWQCB SDWA SWRCB TCA TDS USFWS USEPA UV WDR WWTP United States Army Corps of Engineers Acre-feet Acre-feet per year America Water Works Association Cambria Community Services District Clean Water Act Department of Health Services Environmental Control System, Inc. Engineering News Record Endangered Species Act Feet per second Geographic Information System Gallons per day Gallons per minute Membrane Bio-reactor Maximum Contamination Level Million gallons Million gallons per day Methyl-tert-Butyl-Ether N-Nitrosodimethylamine National Marine Fisheries Services National Pollutant Discharge Elimination System Pounds per square inch Reverse Osmosis Regional Water Quality Control Board Safe Drinking Water Act State Water Resources Control Board Trichloroethane Total Dissolved Solids United States Fish and Wildlife Services United States Environmental Protection Agency Ultraviolet Waste Discharge Requirements Wastewater Treatment Plant Final Report Task 3: Recycled Water Distribution System Master Plan Page v

7 Executive Summary

8 Executive Summary The Cambria Community Services District is phasing the completion of its water master plan through a series of reports. Kennedy/Jenks Consultants is under contract to complete Tasks 3 and 4 of the water master plan. This Task 3 report completes an engineering analysis for a proposed recycled water system. It is also a companion report to a separate Task 3 report on proposed improvements to the District s potable water distribution system. The primary objective of this Report is to provide a Master Planned level layout and associated probable capital costing for a future recycled water system. The use of recycled water diversifies the water supply options for the CCSD, and also provides a level of drought-proofing towards the community s investments in landscaping. Approximately 184 acre-feet per year in irrigation demands were identified for possible service with highly treated wastewater effluent. These demands would be limited primarily to the larger landscaped areas such as the proposed community park, the Santa Lucia Middle School, the Cambria Pines Lodge, the Cambria Nursery, and the new grammar school. Of these potential uses, approximately 99 acre-feet appear to be likely candidates for recycled water due to their proximity to a proposed distribution pipeline. A key issue with the use of recycled water is whether enough water is available from the WWTP during the peak summer demand period. In some communities, the establishment of an artificial habitat for listed species limits the amount of recycled water that may be diverted for irrigation. Of the 99 acre-feet of likely irrigation sites identified, approximately 49 acre-feet would offset existing potable use. This leaves about 50 acre-feet in new demands out of the District s existing hydraulic mound area. To determine whether any impact to sensitive species would occur from the 50 acre-feet of diversion, additional geo-hydrological and biological study would be needed. Sub-surface seasonal storage of recycled water, the use of existing CCSD surface basins, and the use of more efficient irrigation technologies could also offset potential diversion concerns. A subterranean storage site was considered near the District s effluent percolation ponds area for this purpose. The proposed recycled water system consists of advanced treatment facilities at the WWTP, a backbone distribution pipeline, and two pressure zones. A pump station at the WWTP along with gravity storage tanks behind the Santa Lucia Middle School would serve the lower pressure zone. The upper pressure zone would be served by a hydro-pneumatic pumping system next to the gravity storage tanks. The reuse of existing tanks was considered as a means to further reduce construction costs. For example, the old Pine Knolls water tanks are being considered for use at the Santa Lucia Middle School site. The total $5,540,000 cost estimate for the proposed recycled water system is summarized as follows: Treatment facilities $1,500,000 Distribution System $3,440,000 Seasonal storage $ 600,000 Final Report Task 3: Recycled Water Distribution System Master Plan Page ES-1

9 Section 1 Introduction

10 Section 1: Introduction This report presents findings for Task 3 of the Cambria Community Services District s (CCSD) Water Master Plan Update and summarizes the development of a proposed recycled water distribution system. The Task 3 water master planning work has been separated into two reports; a companion report on the potable water distribution system, and this recycled water distribution system report. A separate Task 4 report is also being developed on long-term supply alternatives. Further discussion on the phasing of the water master plan can be found in the Task 3, potable water distribution system report. The recycled water distribution system is being planned for use at larger irrigation demand sites within the CCSD service area. When compared to desalination of seawater for potable use, recycled water requires less energy and may be a better use of resources. In addition, its use will minimize peak hourly and maximum day demands on the CCSD s potable water delivery system. A recycled water system also provides a degree of diversification to the CCSD s water supply along with a level of drought-proofing that serves to protect investments made in the community s landscaping. The report that follows provides basic criteria and costs associated with a recycled water system. These findings are also summarized within the long-term water supply assessment report (i.e., the Task 4 Water Master Plan report). This section summarizes the objectives, scope of services, and conduct of the recycled water system distribution study. 1.1 Background The community of Cambria has approximately 6,400 permanent residents and receives over 20,000 visitors per year that rely on local groundwater resources for their water supply. To meet this water supply need, CCSD operates several wells that withdraw water from shallow aquifers along San Simeon and Santa Rosa Creeks. To prevent seawater intrusion into the San Simeon aquifer during the summer months, the CCSD percolates treated wastewater effluent into the groundwater table between the ocean and up-gradient well field. CCSD s operation of its percolation ponds is subject to conditions of a Waste Discharge Requirements (WDR) Order (Order adopted by the Regional Water Quality Control Board (RWQCB) on December 7, 2001). CCSD has diversion permits issued by the State Water Resources Control Board (SWRCB) for its appropriative water rights on both the San Simeon and Santa Rosa aquifers. During the 1970s, the Santa Rosa Creek aquifer was the sole source of supply for the CCSD. The newer San Simeon well field began producing water in 1979, and has remained the CCSD s primary source of supply. The Santa Rosa aquifer supplements the San Simeon supply, but is of a lower quality due to a higher level of hardness, manganese, and iron. During periods of extended drought there can be insufficient creek flow to restore the groundwater levels in either aquifer. In recent years, the San Simeon aquifer has been used more often during the summer months than the Santa Rosa aquifer. Low well levels in the San Simeon Creek during the mid to late summer and early fall months have lead to past declarations of drought emergencies, emergency water rates to encourage conservation, a moratorium on future water connections, and other water conservation incentives. Final Report Task 3: Recycled Water Distribution System Master Plan Page 1

11 During 1999, CCSD became aware of a methyl tert-butyl ether (MtBE) contamination plume immediately up-gradient from its Santa Rosa Creek wells (Wells SR-1 and SR-3). As a result, and also based on recommendation of the RWQCB, the existing Santa Rosa wells and treatment plant were shut down. During mid-2001, construction of an emergency well (SR-4) and treatment plant was completed up-gradient from the contamination plume area, and on property behind the Coast Union High School. The Santa Rosa and San Simeon Creeks each terminate into separate lagoons prior to entering the ocean. The lagoons provide critical fish habitat for listed species such as the endangered Tidewater Goby, and threatened South-Central Coast Steelhead. Each creek may also provide riparian habitat for listed species such as the California Red-Legged Frog and Southwestern Pond Turtle. Compliance with the Endangered Species Act is listed as a condition in each of the CCSD s appropriative water-rights diversion permits. 1.2 Objectives The primary objective of this evaluation is to provide a comprehensive planning tool to develop and evaluate the proposed recycled water system. This report documents the development and application of a recycled water system model. Because of the long urban-wildland fire interface of the service area, the CCSD also requested an investigation on the potential use of recycled water for fire fighting purposes. Therefore, development of the recycled water system included an analysis of recycled water demands with and without fire flow demands. In addition, the Coast Unified School District is developing its new grammar school with a unique subterranean irrigation and storm water collection system as a means to offset future water system demands. This report also includes consideration of recycled water to further supply or augment the waterconserving measures currently under development. Potential recycled water sites were spilt into two basic categories. The first category of sites replace the existing use of potable water, primarily used as irrigation water, with future recycled water. This first category of sites will not affect the net water balance within the watersheds. A second category of sites was developed for future irrigation sites that could conceivably increase the net amount of water leaving the watersheds. An example of such a new demand is the community park that is currently being considered by the CCSD. Due to constraints posed mainly by the Endangered Species Act, further study of the potential downstream impacts to the San Simeon lagoon may be required in order to achieve future environmental clearances associated with the diversion of recycled water to new water demand areas. Detailed hydro-geological and biological study associated with the lagoons was not within the scope of work of this study. However, related to addressing this potential concern is a no net increase strategy based in part on the unique and efficient irrigation system presented to CCSD by the Coast Unified School District. A no net increase strategy may also incorporate the innovative irrigation technology along with seasonal storage of recycled water that would minimize the need to rely upon on-site storage and collection of stormwater, while also meeting a multi-year drought scenario. Further reduction in demand was also considered by converting irrigated turf grass areas to non-irrigated areas. An example of this would be areas within the existing elementary school that will not require irrigation after school use is converted to administrative offices. Final Report Task 3: Recycled Water Distribution System Master Plan Page 2

12 To achieve its objectives, CCSD authorized Kennedy/Jenks Consultants to develop a hydraulic model and evaluate CCSD s water and recycled water systems under an Agreement for Engineering Services dated 25 October The evaluation of the CCSD s potable water distribution system is presented in a separate report. 1.3 Scope of Services To accomplish this objective, the following scope of services was developed: Develop Design and Unit Cost Criteria Modeling and Analysis of the Recycled Water Systems Develop Recycled Water Demand Criteria and Demand Projection 1.4 Conduct of the Study The information developed in this study is based on information provided by CCSD, discussions with CCSD staff, and computer-based hydraulic analysis. Initial phases of the study focused on the collection and review of information related to potential users and CCSD facilities so that system models could be developed. A commercially available model (H 2 0NET Version 3.1) was utilized. Subsequent phases were focused on demand data, which forms the basis for projected demand patterns. The peaking factors of potential recycled water demands were taken from comparable recycled water planning criteria. Fire flow criteria and selected levels of fire protection were provided by CCSD. Based on the model, recycled water demand projections, and fire flow criteria, CCSD s recycled water system was configured and facility locations were recommended. The estimated capital cost of the recommended improvements and implementation plan are presented. Final Report Task 3: Recycled Water Distribution System Master Plan Page 3

13 Section 2 Recycled Water Supply and Demand Projections

14 Section 2: Recycled Water Supply and Demand Projections This section discusses projected recycled water supply and demands utilized in the recycled water system model for the evaluation of reservoir and pumping facilities. Additional storage options are discussed to address habitat concerns. Related to this discussion, more efficient irrigation methods are being considered for the new community park and elementary school to reduce demands on the aquifers. 2.1 Recycled Water Supply CCSD operates a one million gallon per day (MGD) extended aeration wastewater treatment plant (WWTP) located southwest of the intersection of Windsor Boulevard and State Highway 1. The WWTP provides treatment of wastewater from Cambria as well as from the State operated campground at San Simeon Creek. The current dry weather flow of the plant is approximately 650,000 gallons per day (gpd). Presently, the treated wastewater effluent is percolated into the ground between the San Simeon well field and the Pacific Ocean to create a hydraulic barrier that slows the fresh water underflow in the San Simeon Creek aquifer. This mound of fresh water also prevents seawater intrusion into the up-gradient potable groundwater aquifer, and maintains down-gradient surface flows. Figure 2-1 illustrates the overall concept being used in the San Simeon aquifer. FIGURE 2-1 SEAWATER INSTRUSION CONCEPT FOR CCSD Cross Sectional View Of San Simeon Creek Based upon the empirical observations of key CCSD operating personnel, the amount of water required to maintain the hydraulic mound varies seasonally. During dry months, the water table within the up-gradient San Simeon well field is drawn down to meet with the increased dry season demand. Consequentially, CCSD operating staff occasionally need to pump down the hydraulic mound to maintain the positive flow differential between the two fields (i.e. maintain flow moving from the up-gradient well field to the down-gradient percolation ponds). This procedure, as required to meet the WDR, prevents potential cross contamination with the upgradient potable well field. Such operations are normally required late in the summer months when the up-gradient San Simeon well field is at its lowest level. When the need occurs, CCSD Final Report Task 3: Recycled Water Distribution System Master Plan Page 4

15 operators run an existing non-potable well located within the center of the percolation ponds. This non-potable well pumps into the CCSD s Van Gordon surface storage reservoir, with any overflows going into the creek and downstream lagoon. Because of the lowered potable well-field levels during the dry season, down-gradient percolation of the entire wastewater effluent flow may not be desired or necessary. Accordingly, a portion of the wastewater effluent may be available for recycled water use. Plant operations staff have estimated that during the dry season months, approximately 250,000 gpd may be required to be percolated into the aquifer to maintain the hydraulic barrier. This assumption allows for a conservative estimate of barrier needs and recycled water availability. Based on a dry weather flow of 650,000 gpd, approximately 400,000 gpd of wastewater effluent would be available for recycled water use during the dry months. However, this number may require further refinement through subsequent study due to potential habitat concerns within the downstream lagoon area. In certain communities, the City of San Luis Obispo for example, a portion of the treated wastewater plant effluent was deemed necessary to support critical habitat. Although not a natural source of water, precedents have also been set elsewhere within the state that limit the diversion of treated effluent from streams where an artificially created habitat supports endangered species. Due to similar potential habitat concerns, this report developed two categories of potential recycled water users: (1) existing sites where potable water use would simply be converted to recycled water and have no net impact on the balance of water within the San Simeon watershed; and, (2) future recycled water demand sites that could increase water withdrawn from the San Simeon watershed. Potential habitat concerns may also be further addressed by seasonal off-stream storage of recycled water and innovative water conservation measures. Seasonal storage of recycled water would involve storing recycled water during the wet season for dry season use. Despite the need to constantly supply the mound with 250,000 gpd of effluent, more water is available for recycled water use during wet months due to the higher plant flow (1 mgd) and reduced impacts to the down-gradient stream flows. Innovative water conservation being considered includes a sub-surface irrigation method similar to hydroponics technology, as well as harvesting and storing local storm water runoff at future project sites. Seasonal storage of recycled water is further discussed in Section 2.3 and in the Task 4 report on long-term supply options. Additionally, subsequent study of the habitat issues and related geohydrology could further validate the empirical observations and opinions expressed by operating staff on the volume of recycled water available during the summer irrigation season. 2.2 Projected Recycled Water Demand Recycled water demand was determined by multiplying the irrigable acreage from the potential recycled water users by a recycled water application rate. This application rate was calculated for turf-type vegetation because the recycled water will be mainly used for irrigation of turf Potential Recycled Water Users Potential recycled water users were identified by CCSD staff. The potential users are existing non-residential potable water users who have significant irrigable area. Irrigable acreage was determined by CCSD staff from aerial photos and geographical information system (GIS) data. Final Report Task 3: Recycled Water Distribution System Master Plan Page 5

16 Because of potential habitat concerns, recycled water users were divided into existing customers that are likely to use recycled water, future customer sites, and existing customers that are less likely to convert to recycled water. Potential recycled water users and their irrigable areas are shown in Table 2-1. Figure 2-2 presents the locations of the potential recycled water users. Residential customers were not included in the estimate for recycled water due to their relatively low demand when compared with the high cost to install distribution piping. Additionally, the use of recycled water on residential customers creates a risk of cross connection with the potable water system. This concern stems from a greater potential for amateur plumbers to interconnect potable and non-potable pipes. Larger irrigation customers are more likely to have trained staff or licensed contractors perform on-site plumbing modifications. Having fewer larger customers on recycled water also limits the number of monitoring requirements for backflow prevention testing and cross connection tests. For these reasons, agencies planning recycled water have not included the residential customers. Where recycled water has been planned for residential areas, it is generally in larger-scale, new developments on front yards where landscaping is tightly controlled and maintained by a homeowners association. While planning its last WWTP upgrade in 1990, the CCSD also investigated the use of recycled water on agricultural lands among other alternatives. This was followed up with pilot testing, but was ultimately canceled following opposition from the agricultural community. Other alternatives considered during the early 1990s included direct recharge of the aquifer using recycled water. For example, the Orange County Water District has an indirect recharge of its aquifer system using recycled water. Conversely, other agencies, such as the Dublin San Ramon Services District, have abandoned their attempts at similar direct recharge approaches due to public opposition. Due to past opposition from the agricultural community and the contentious nature of direct recharge systems, this report did not include agricultural users outside of the CCSD s services boundary. Determination of Application Rate Recycled water demands were calculated using irrigable acreage of each potential user and an application rate for turf-type vegetation. Turf grass is the most prevalent type of landscaping for the potential recycled water users. An estimate for irrigation demands was based on the following formula: Irrigation demand (inches) ={[k c (ET o ) P] x LR} / IE Where: k c = a crop coefficient factor of 0.8 for warm weather grasses 1 ET o = reference crop evapotranspiration 2 P= precipitation in inches 3. LR= leaching rate past the root zone. IE= irrigation efficiency. For conventional irrigation systems, approximately 25 percent of precipitation is lost to run-off, an additional 10 percent is needed to pass salts through the root zone, and irrigation efficiency is 70 percent. Thus the equation simplifies to: 1 DWR Bulletin USGS Report , Yates & Von Konyenburg, Table 5, p.53 3 Average of monthly values from WWTP gage, 1974 through 1992 Final Report Task 3: Recycled Water Distribution System Master Plan Page 6

17 Irrigation demand (inches) = {[0.8(ET o ) (P x 0.75)] x 1.10} / 0.70 The Table 2-2 provides the average irrigation demand per month for a conventional irrigation system. The development of this table used evapotranspiration and precipitation data from a United States Geological Survey (USGS) report entitled, Hydrogeology, Water Quality, Water Budgets, and Simulated Responses to Hydrologic Changes in Santa Rosa and San Simeon Creek Ground Water Basins, conducted by Yates and Konyenburg, dated Final Report Task 3: Recycled Water Distribution System Master Plan Page 7

18 Legend Potential Recylced Water Users Wastewater Treatment Plant Pump Station ("Cantex" Tank Location) Zone 1 Tank Site & Zone 2 Booster Pump Station µ Not To Scale Cambria Community Services District Recycled Water System Modeling Potential Recycled Water Users K/J Figure 2-2

19 TABLE 2-1 POTENTIAL RECYCLED WATER USERS Total Acreage Percent Irrigable (a) Irrigable Acreage Potential Recycled Water User Likely Recycled Water Sites A. Existing Potable Water Irrigation Sites Existing WWTP site % 0.75 Mid State Bank % 0.07 Santa Rosa Catholic Church 2 20% 0.40 Tamson Dr. commercial areas 9.5 5% 0.48 Cambria Grammar school (as CUSD offices) % 1.12 Cambria Pines Lodge % 8.19 CCSD Fire Station % 0.42 Presbyterian Church % 1.04 Cambria Nursery % 1.96 Santa Lucia Middle School 10 40% 4.00 St. Paul's Episcopal Church % 0.35 Subtotal B. Future Recycled Water Irrigation Sites CCSD vacant lot across from Vets Hall % 0.22 Future CCSD Community Park % Main Street Landscaping % 0.99 Future Elementary School 12 35% 4.20 Future Vineyard Church site % 0.53 Subtotal Subtotal of Likely Recycled Water Sites Less Likely Recycled Water Sites C. Riparian Well Services Shamel Park % 1.73 Coast Union High School % 8.36 Subtotal D. Low Priority Sites Due To Distance From Main Recycled Water Pipeline Cambria Cemetery % San Simeon Pines Motel % 5.11 San Simeon State Camp Grounds 25 25% 6.25 Subtotal Subtotal of Less Likely Recycled Water Sites Total Irrigable Acreage of Likely & Less Likely Sites Note: (a) Percent irrigable land determined from land coverage estimates from aerial photos and GIS data. Final Report Task 3: Recycled Water Distribution System Master Plan Page 8

20 TABLE 2-2 ESTIMATED IRRIGATION DEMAND FOR CCSD USING A CONVENTIONAL SYSTEM Average Precipitation (Inches) (c) Average Irrigation Demand (Inches) (d) Monthly Peaking Factor (e) Month Reference (a) ET o Crop Coefficient (b) January February March April May June July August September October November December Annual Demand (Inches) Annual Demand (Feet) 2.63 Notes: (a) From 1998 USGS Report , Yates & Von Konyenburg, Table 5, p.53. (b) k c value of 0.8 based on warm weather turf grass, see DWR Publication (c) Average of monthly values from WWTP gage, 1974 through (d) Irrigation Demand = [k c x ET 0 - (P x 0.75)] x LR x (1/IE). (e) Divided monthly value by monthly average. In addition to conventional system, the Coast Unified School District has started constructing a unique subterranean irrigation system and storm water collection and storage system for its new grammar school. This system is also under consideration for the Santa Lucia middle school. The system under construction at the middle school is a proprietary Evaporative Control Systems, Inc. (ECS) irrigation system that irrigates plants from the root zone upward. The system consists of subterranean pans and pipes placed under turf grass, with sand and top soil placed above the distribution system. Appendix A contains further information on the ECS system being constructed. For an ECS system, no precipitation is lost to run-off, no additional water is required to pass salts through the root zone, and irrigation efficiency is assumed to be 100 percent. Thus the earlier irrigation demand equation simplifies to: Irrigation demand (inches) = {[0.8(ET o ) (P x 1.0)] x 1.0} / 1.0 The Table 2-3 provides the irrigation demand for an ECS irrigation system when using evapotranspiration and precipitation data from the 1998 USGS report. Final Report Task 3: Recycled Water Distribution System Master Plan Page 9

21 TABLE 2-3 ESTIMATED IRRIGATION DEMAND FOR CCSD USING AN ECS SYSTEM Average Precipitation (Inches) (c) Average Irrigation Demand (Inches) (d) Monthly Peaking Factor (e) Month Reference (a) ET o Crop Coefficient (b) January February March April May June July August September October November December Annual Demand (Inches) Annual Demand (Feet) 1.59 Notes: (a) From 1998 USGS Report , Yates & Von Konyenburg, Table 5, p.53. (b) k c value of 0.8 based on warm weather turf grass, see DWR Publication (c) Average of monthly values from WWTP gage, 1974 through (d) Irrigation Demand = [k c x ET 0 - P] x LR x (1/IE). (e) Divided monthly value by monthly average. From Table 2-3, the average irrigation demand could be as low as 19 inches per year with the ECS system compared to the 31.5 inches calculated for a conventional irrigation system. Besides the new grammar school, the ECS system and its lower irrigation demands could be a candidate for the Santa Lucia middle school as well as the future community park. The values in Table 2-3 do not account for additional savings that could occur from a localized water harvesting system, such as the system under construction at the new grammar school. The inch annual precipitation total from Table 2-3 is close to the annual irrigation demand when using the ECS System. This suggests that in a normal rainfall year, the ECS System will conceivably meet all irrigation demands by collecting stormwater from the area being irrigated. For drier years, more storm water collection area and on-site storage is needed. Alternatively, and in conjunction with the ECS subterranean irrigation system, recycled water could be supplied to minimize the amount of on-site storm water storage and collection that may otherwise be needed. Additionally, recycled water will provide further protection against the loss of mature landscaping should a multiple year drought occur. Therefore, recycled water is being planned as a back up to the new grammar school s innovative ECS System as well as other larger scale irrigation sites. Final Report Task 3: Recycled Water Distribution System Master Plan Page 10

22 2.2.2 Potential Recycled Water Demand Peaking Factors Demands for recycled water are seasonal, with the highest demands occurring during the summer months. Additionally, demand fluctuates during the day, with most irrigation demand occurring at night. Accordingly, maximum daily and peak hour demand factors were developed to accommodate the diurnal seasonal demand patterns. Peaking factors were applied to average daily demands to estimate water demands for maximum day and peak hour demand scenarios. The peaking factors used to develop maximum day and peak hour demands are presented in Table 2-4. Lower peaking factors could also apply if the ECS system were ultimately utilized at the future community park, and existing middle school. However, for master planning purposes, the more conventional peaking factors below are recommended. Peaking factors were derived from recycled water planning criteria for comparable areas. TABLE 2-4 MAXIMUM DAY AND PEAK HOUR FACTORS Condition Peaking Factor Maximum Day 2.70 Peak Hour Average Daily Demand Average daily demands were calculated by multiplying the annual demand (in feet) as calculated in Table 2-2 by the total amount of irrigable land (total for likely and less likely recycled water sites, per Table 2-5). Based on this approach and assuming conventional irrigation methods, the estimated average daily demand for the recycled water system is 114 gallons per minute (gpm) or 184 AFY. Using ECS for irrigation and the Annual Demand (in feet) developed in Table 2-3 for the future community park, the future elementary school, and the existing Santa Lucia middle school, the total average daily demand would be approximately 100 gpm (162 AFY). This later number assumes there would be either a multiple year drought scenario with no rainfall during one rainfall season, or no local water harvesting occurring at these sites. If storm water runoff was captured and stored (i.e., harvested) at these sites, the average daily demand would be reduced by the total irrigation demand of these sites (33 AFY, with ECS) and lowered to approximately 80 gpm (129 AFY) with ECS. Table 2-5 provides a summary of the individual user irrigable demand, with and without an ECS system. Further detail for individual users average day, maximum day and peak hour demands for conventional and ECS irrigation systems, are provided in Appendix B. 2.3 Seasonal Storage Opportunities As discussed in Section 2.1, effluent from the WWTP is currently discharged to percolation/evaporation ponds. Studies beyond the scope of this report would be required to prove whether any reduction to the hydraulic mound recharge would impact the habitat within the lagoon. These studies would most likely include detailed geo-hydrological modeling and biological assessments. As recycled water demand is highest in the summer and lowest in the winter, seasonal storage may mitigate potential impacts to the downstream lagoon and enable additional recycled water supply to be available during high water use months. Additionally, seasonal storage could be used to offset any increase in basin demand. Final Report Task 3: Recycled Water Distribution System Master Plan Page 11

23 TABLE 2-5 PROJECTED RECYCLED WATER DEMAND (AFY) Irrigable Demand (AFY) Irrigable Demand W/ECS (AFY) Potential Recycled Water User Likely Recycled Water Sites A. Existing Potable Water Irrigation Sites Existing WWTP site Mid State Bank Santa Rosa Catholic Church Tamson Dr. commercial areas Cambria Grammar school (as CUSD offices) Cambria Pines Lodge CCSD Fire Station Presbyterian Church Cambria Nursery Santa Lucia Middle School St. Paul's Episcopal Church Subtotal B. Future Recycled Water Irrigation Sites CCSD vacant lot across from Vets Hall Future CCSD Community Park Main Street Landscaping Future Elementary School Future Vineyard Church site Subtotal Subtotal of Likely Sites Less Likely Recycled Water Sites C. Riparian Well Services Shamel Park Coast Union High School Subtotal Cambria Cemetery San Simeon Pines Motel San Simeon State Camp Grounds Subtotal Subtotal of Less Likely Sites Total of Likely & Less Likely Final Report Task 3: Recycled Water Distribution System Master Plan Page 12

24 2.3.1 Seasonal Supply and Demand Balance Due to the need to maintain a hydraulic mound to prevent salt water intrusion, differences in monthly production and use of recycled water affect total annual use. The WWTP produces effluent at a more or less uniform rate throughout the year, however, the amount of effluent available for recycled water use will vary depending on the season. Additionally, since the recycled water will be used for irrigation, demand will peak during the summer months and be significantly less to near zero during the winter months. As a result, recycled water production may not be adequate to meet demands in summer months, while in winter months, surplus effluent may exist. Due to potential habitat concerns and the desire to maintain no net increase to the aquifer during the summer seasonal storage of recycled water may be required. Projected recycled water demand and available supply are shown in Table 2-6 and in Figure 2-3. Demand includes all potential recycled users and a conventional irrigation system. Based on this analysis, seasonal storage would not be required. However, if the hydraulic mound requires more water than empirical observation suggests, CCSD may not be able to meet recycled water demand. Accordingly, it would be desirable to provide seasonal storage to ensure sufficient supply and to avoid any potential habitat concerns at the down-stream lagoon. TABLE 2-6 PROJECTED RECYCLED WATER DEMAND VS. SUPPLY Required For Hydraulic Mound (mgd) (a) Excess (+) / Deficit (-) (mgd) Available Supply User Demand Month (mgd) (b) (mgd) January February March April May June July August September October November December Average Notes: (a) During the winter, the basins normally fill during November and may remain full though May or June. Therefore, the mound requirement could be zero during the rainy season depending upon the timing of rainfall events and the amount of rain. (b) Available supply is total supply minus flow required for hydraulic mound. Assuming 1.0 mgd during wet season and 0.65 mgd during the dry season No Net Change Concept Due to the potential impact of the percolated water on down-gradient stream flow, an appropriative water rights diversion permit may be required to allow alternate use of recycled water that is currently percolated into the San Simeon Creek aquifer. Accordingly, regulating agencies may require proof that the down-gradient habitat is not being impacted. Therefore, Final Report Task 3: Recycled Water Distribution System Master Plan Page 13

25 MGD \\VEN2\share\PROJECTS\2002\ \Recycled Water\Final Draft\Figure 2-3.ppt Jan-03 Feb-03 Mar-03 Apr-03 May-03 Jun-03 Jul-03 Aug-03 Sep-03 Oct-03 Nov-03 Dec-03 Total Demand Total Available supply Required for Hydraulic Mound Excess/Deficit Month Kennedy/Jenks Consultants Cambria Community Services District Recycled Water System Modeling Seasonal Recycled Water Supply vs. Demand June 2003 K/J Figure 2-3

26 several approaches were considered. One approach is to conduct a detailed geo-hydrological study to prove there would be no impact to the downstream habitat from the additional diversion of recycled water to future demand sites. Another approach is to prevent any increased diversion on the watershed from the existing potable water diversions. This later approach may involve combining the more water efficient ECS irrigation system with recycled water use, or perhaps harvesting and storing storm water on each site. With the collection of storm water, there would be more risk to landscaping if a multi-year drought were to occur, and greater tank storage needs. Therefore, a combined system using the ECS irrigation system with a recycled water supply was considered. The ECS system was evaluated for use at the Santa Lucia Middle School, the future elementary school site, and a small portion of the existing grammar school site. The future park site may also be a candidate for an ECS system, but costs would need to be assessed further. Moving the irrigated playing fields to the San Simeon basin s (e.g., the old Molinari Ranch area currently being acquired by CCSD and the American Land Conservancy) was also considered as a means to further reduce potential impacts on the hydraulic mound and lagoon system. Relocating the irrigated park playing fields to the Molinari Ranch area would result in approximately 30 percent of the applied water being returned to the hydraulic mound via underflow through the groundwater. Besides these concepts, CCSD may also develop a larger seasonal storage system for all of its future recycled water demands. Seasonal storage would provide water during the peak summer months to ensure no reduction of flow into the lagoon area. It should be noted that with the implementation of an additional long-term potable water supply as evaluated in the Task 4 would provide an additional supply not dependent on the basin. Thus, less potable water would be pumped form the basin. Accordingly, recycled water diversion for the future sites should be offset by the reduction in potable water production, resulting in a no net change of basin demand. However, since at this time, the time frame for implementation of a long-term water supply is unclear, an alternate method of reducing basin demand should be evaluated Above Ground Seasonal Storage A seasonal recycled water reservoir would provide storage for excess recycled water produced during winter months without affecting the aquifer balance during the dry season. However, above ground storage of recycled water in an open reservoir may offer significant operational challenges. During the many months when the reservoir is full, algae have the opportunity to grow, creating potential water quality problems and odors. Filtration, disinfection, or other treatment may become necessary, further increasing both capital and operational cost. Additional cost may result from required infrastructure to convey the recycled water to the storage facility. Assuming an ECS system would be utilized at the Santa Lucia middle school, future grammar school, and future community park, the future recycled demand would be 32 AFY. However, it has been recently proposed to move the irrigated play fields of the future community park to the Molinari Ranch property located within the San Simeon Basin near the lagoon. As per the 1998 report, 30 percent of the recycled water applied to the play fields would be returned to the basin. Additionally, approximately 5.6 AFY or irrigation return flow would be returned to the San Simeon basin from the recycled water use at WWTP and San Simeon State Camp Grounds. The existing CCSD surface reservoirs at Van Gordon near the spray fields and flow equalization basins at the WWTP could provide seasonal storage of the recycled water to further offset demand increases. Furthermore, due to recent delays in the development of the future community park, it is unlikely that it would be developed prior to implementation of a new longterm potable water supply. Accordingly, it is assumed that any increase on basin demand from Final Report Task 3: Recycled Water Distribution System Master Plan Page 14

27 the community park would be offset by the reduction of potable demand from the basin due to the new potable water source. This would result in a no net change in basin demand. Table 2-7 summarizes the basin demand balance concept. TABLE 2-7 BASIN DEMAND BALANCE Reason for Change Future Recycled Water Users (w/ecs system) Irrigation Return Flow from Future Community Park play fields at Molinari Ranch to San Simeon Basin Irrigation Return Flow to San Simeon Basin from the WWTP and State Camp Grounds Storage at Existing CCSD Van Gordon Surface Reservoir Storage at Existing WWTP Equalization Basins Reduction in San Simeon Potable Demand from New Long-Term Potable Supply Total Net Change Net Change in Basin Demand (Increase (+)/Decrease (-) +32 AFY -6.3 AFY AFY AFY -1.5 AFY -9.6 AFY 0 AFY However, if the community park is developed prior to the long-term potable supply, CCSD could provide an above ground seasonal storage reservoir or subterranean storage (as discussed below) to offset the change in basin demand. Additionally, a detailed hydrologic and biological study of the downstream lagoon area could be conducted to determine the impacts to the habitat from the change in mound volume. Above ground storage of recycled water is difficult to implement because sites must be close to the proposed recycled water system, but sufficiently distant from existing and planned development. One potential location for the seasonal storage area is the 3.5-acre storm water detention pond near Highway 1 and Cambria Drive (the old Mid-State Bank property). Assuming 4 feet of depth, the pond may provide 14 AF of storage. Surface storage would need to be further assessed with regard to treatment needs due to potential algae blooms, as well as potential environmental issues Subterranean Storage in the San Simeon Basin As an alternative to relying on the implementation of the future potable water supply, the community park demand could be offset by the construction of a subterranean storage site. This approach would consist of a subterranean cut-off walls outside of the riparian corridor in the vicinity of the CCSD s percolation ponds. Three walls would be constructed, two of which would be perpendicular to the bedrock that forms the channel below the alluvium. A third wall would parallel the channel formed by the bedrock. This concept is a modification to the subterranean dam, as presented in a draft proposal entitled, Methods for Improving San Simeon Creek Water Storage Conceptual Proposal, dated 2003 prepared by W.C. Bianchi and K. Renshaw. By staying out of the creek and riparian areas, certain environmental issues could be avoided or minimized. However, further detailed geotechnical investigations would also be needed to ensure other potential hydraulic pathways, such as fractured rock seams, were not present. Final Report Task 3: Recycled Water Distribution System Master Plan Page 15

28 The site considered for the side channel storage system is shown in Figure 2-4. The side channel storage system would consist of slurry walls extended into underlying bedrock and key into the bedrock as it slopes up and to the north from the main channel. As determined by the 1998 report, the bedrock profile slopes downward towards the main channel. Additionally the useful storage out of the contained area would need to be below the low summer time well levels in order to maintain a positive gradient from the upstream well field. Typically, the summer time well levels bottom at around 4 to 5 feet above, mean sea level. Assuming a 4.9-acre surface area as shown, 30 feet of depth and a storage coefficient of about 0.1 (1998 report) the volume in the subterranean storage is about 14.7 AF. A prime advantage of an off-channel subterranean storage system over an underground dam, would be the avoidance of some of the andramodous fish impacts commonly associated with dams. Further, evaporative losses are minimal due to storage being below ground. Construction costs are anticipated to be between $10 per square foot. Assuming walls that total 2,000-feet in length and 30-feet in depth, the estimated capital cost (2002 dollars) is approximately $600,000. Final Report Task 3: Recycled Water Distribution System Master Plan Page 16

29 Potential subterranean recycled water storage \\VEN2\share\PROJECTS\2002\ \Recycled Water\Final Draft\Figure 2-4.ppt Kennedy/Jenks Consultants Cambria Community Services District Recycled Water System Modeling Location of Proposed Subterranean Storage June 2003 K/J Figure 2-4

30 Section 3 Regulatory Requirements

31 Section 3: Regulatory Requirements Production, discharge, distribution, and use of recycled water are subject to federal, state, and local regulations, the primary objectives of which are public health and environmental protection. This section describes the regulatory requirements and their administration. 3.1 Federal Requirements Two federal acts regulate the discharge and use of recycled water or wastewater: the Clean Water Act and the Safe Drinking Water Act Clean Water Act Federal requirements relevant to the discharge of recycled water, or wastewater, and any other liquid wastes to navigable waters are contained in the 1972 amendments to the Federal Water Pollution Control Act of 1956, commonly known as the federal Clean Water Act (CWA) (Public Law ). The CWA created the U.S. Environmental Protection Agency (USEPA) and established the National Pollutant Discharge Elimination System (NPDES), a permit system for discharge of contaminants to navigable waters. NPDES requires that all municipal and industrial dischargers of liquid wastes apply for and obtain a permit prior to initiating discharge Safe Drinking Water Act Federal requirements relevant to the use of recycled water for groundwater recharge are contained in the 1986 amendments to the Safe Drinking Water Act (SDWA) of 1974 (Public Law ). The SDWA focuses on regulation of drinking water and control of public health risks by establishing and enforcing maximum contaminant levels (MCLs) for various compounds in drinking water. The 1986 amendments also established requirements for protection of groundwater supplies through wellhead protection programs and regulation of underground injection of wastes Endangered Species Act Compliance The CCSD has listed as part of its SWRCB diversion permits, compliance with the Environmental Species Act. This is particularly significant due to the presence of tidewater gobies (currently listed as endangered ), and young-of-the-year south central coast steelhead (currently listed as threatened ) within the lagoon. Biological evaluations are often required to comply with the Endangered Species Act (ESA). Section 7 of the ESA requires all federal agencies to use their authority to conduct conservation programs and to consult with National Marine Fisheries Service (NMFS) or U.S. Fish and Wildlife Service (USFWS) concerning the potential effects of their actions on any species listed under the ESA. Consultations occur with federal action agencies under Section 7 of the ESA to avoid, minimize, or mitigate the impacts of their activities on listed species. USFWS and NMFS also review non-federal activities which may affect species listed under the ESA and issues permits under Section 10 for the incidental take of those species and for scientific research and enhancement purposes. If diversion of recycled water from the mound to future demand sites results in the loss (i.e., taking ) of listed species, the Section 10 issuance criteria requires NMFS or USFWS to issue an Incidental Take Final Report Task 3: Recycled Water Distribution System Master Plan Page 17

32 Permit. In order to receive an incidental take permit, a habitat conservation plan is typically required to ensure the offset of any taking is achieved. The decision to grant or deny a permit is dependent upon a public interest review of the probable impacts of the proposed activity and its intended use. Benefits and detriments are balanced by considering effects on conservation, economics, wetlands, wildlife, flood hazards, navigation, water quality, and the needs and welfare of the public. Guidelines restrict discharges into aquatic areas when there are less environmentally damaging, practicable alternatives. Reasonable and practicable mitigation of unavoidable impacts will be required. A permit will be granted unless the project is found to be contrary to the public interest or fails to comply with the guidelines. U.S. Army Corp of Engineers (USACE) is required to consult with state and federal wildlife agencies regarding any impacts of a project on aquatic habitats Administration In the State of California, the administration and enforcement of the NPDES and SDWA programs have been delegated to the state. 3.2 State Requirements State requirements for production, discharge, distribution, and use of recycled water are contained in the California Water Code, Division 7 - Water Quality, Sections 1300 through (Water Code); the California Administrative Code, Title 22-Social Security, Division 4 - Environmental Health, Chapter 3 - Reclamation Criteria, Sections through (Title 22); and the California Administrative Code, Title 17 - Public Health, Chapter 5, Subchapter 1, Group 4 - Drinking Water Supplies, Sections 7583 through 7630 (Title 17). In addition, guidelines for production, distribution, and use of recycled water have been prepared or endorsed by state agencies administering the recycled water regulations Water Code The Water Code contains requirements for the production, discharge, and use of recycled water. The Porter-Cologne Water Quality Control Act (Division 7 of the California Water Code), which was promulgated in 1969, established the State Water Resources Control Board (SWRCB) as the state agency with primary responsibility for the coordination and control of water quality, water pollution, and water rights (Division 7, Chapter 1). Nine Regional Water Quality Control Boards (RWQCB) were established to represent the SWRCB regionally and carry out the enforcement of water quality and pollution control measures (Division 7, Chapter 4). In addition, each RWQCB was required to formulate and adopt water quality control plans and establish requirements for waste discharge to waters of the state. In 1972, Chapter 5.5 was added to Division 7 to provide the RWQCBs with the authority to carry out the provisions of the federal CWA. The Central Coast RWQCB has jurisdiction over Cambria. CCSD currently has WDR from the RWQCB, which would need to be amended for the recycled water diversions. As mentioned previously, this may require proof that the use of recycled water would not negatively impact the basin. Division 7, Chapter 7 - Water Reclamation, was included in the Porter-Cologne Water Quality Control Act in Subsequent amendments required the Department of Health Services Final Report Task 3: Recycled Water Distribution System Master Plan Page 18

33 (DHS) to establish water reclamation criteria, gave the RWQCB the responsibility of prescribing specific water reclamation requirements for water which is used or proposed to be used as recycled water, provided for the regulation of injection of waste into the ground, and required the use of recycled water, if available, rather than potable water for irrigation of greenbelt areas. In addition to Division 7, Chapter 7, Sections 1210 through 1212 of the Water Code, added in 1980, focus on the ownership of treated wastewater and require that the owner of a wastewater treatment plant obtain approval from the SWRCB prior to making any change in the point of discharge, place of use, or purpose of use of treated wastewater. Thus before CCSD could incorporate a recycled water system, approval from the SWRCB must be obtained Title 22 In 1975, Title 22 was prepared by DHS in accordance with the requirements of Division 7, Chapter 7 of the Water Code. In 1978, Title 22 was revised to conform with the 1977 amendment to the federal CWA. The requirements of Title 22, as revised in 1978, 1990, and 2001, regulate production and use of recycled water in California. Title 22 requirements are summarized in Figure 3-1. Title 22 establishes the quality and/or treatment processes required for an effluent to be used for a specific non-potable application. The following categories of recycled water are identified: Disinfected tertiary recycled water Disinfected secondary-2.2 recycled water 4 Disinfected secondary-23 recycled water 5 Undisinfected secondary recycled water In addition to recycled water uses and treatment requirements, Title 22 addresses sampling and analysis requirements at the treatment plant, preparation of an engineering report prior to production or use of recycled water, general treatment design requirements, reliability requirements, and alternative methods of treatment. A draft regulation issued 23 April 2001 specifically addresses Groundwater Recharge Reuse. The regulations address requirements for the engineering report and monitoring and reporting for projects that use recycled water for groundwater recharge Title 17 Title 17 focuses upon the protection of drinking (potable) water supplies through control of cross-connections with potential contaminants, including non-potable water supplies such as recycled water. Title 17, Group 4, Article 2 - Protection of Water System, Table 1, specifies the minimum backflow protection required on the potable water system for situations in which there is potential for contamination to the potable water supply. 4 The 2.2 refers to the coliform count requirement for the water 2.2 MPN/100 ml. 5 The 23 refers to the coliform count requirement for the water 23 MPN/100 ml. Final Report Task 3: Recycled Water Distribution System Master Plan Page 19

34 Title 22, Article 3 - Uses of Recycled Water Irrigation Section Impoundments 2/ Section Cooling Section Other Purposes Section (Par. a) (Par. b) Food Crops (contact w/edible portion) Parks & Playgrounds School Yards Residential Landscaping Unrestricted Access Golf Courses Food Crops (not in contact w/edible portion) (Par. c) (Par. d) (Par. a) (Par. a) (Par. b) Non-restricted Recreational Impoundments Cemeteries Freeway Landscape Restricted Access Golf Courses Nursery Stock & Sod, not restricted Pasture - Animal Producing Milk Non-Edible Vegetation Areas not used for Recreation Orchards Vineyards Non-Food Bearing Trees Fodder, Fiber Crops and Pasture Seed Crops (no human consumption) Food Crops (with pathogen destroying process-human consumption) Nursery Stock and Sod Farms (restricted) Cooling Towers Evap. Condensers Spraying Other Mist Devices Cooling & Air Conditioning - No Mist (Par. b) (Par. a) Flushing Toilets & Boiler Feed Urinals Non-struct Firefighting Priming Drain Backfill - Non-potable Traps Piping Industrial Process Soil Compact Water Mixing Concrete Structural Fire Dust Control Fighting Washdown Decorative Fountains Commercial Laundries Backfill - Potable Water Lines Snow Making Car Washes Disinfected Tertiary Recycled Water Disinfected Secondary - 23 Recycled Water Disinfected Secondary - 23 Recycled Water Undisinfected Secondary Recycled Water (Par. a) (Par. b) Disinfected Tertiary Recycled Water With Conventional Treatment Disinfected Tertiary Recycled Water Without Conventional Treatment Disinfected Tertiary Recycled Water Disinfected Secondary - 23 Recycled Water Disinfection Tertiary Recycled Water Filtered Oxidized Wastewater 1/ Coagulated Filtered 5 gpm/sf Turbidity - 2 NTU Average 5 NTU (5%), 10 NTU Max. OR Ultra, Nano, or RO, Membrane Turbidity not-toexceed 0.2 NTU 5% w/i 24 hours, 0.5 NTU Max. Disinfected (after filtration) CT 450 mg-min/l w/90 min. Modal Contact OR 5-log Virus AND 2.2 MPN/100 ml, 7- Day Median 240 MNP/100 ml Max. Oxidized & Disinfected 1/ 2.2 MPN/100 ml, 7- Day Median 23 MPN/100 ml Max. Kennedy/Jenks Consultants Oxidized & Disinfected 1/ 23 MPN/100 ml, 7- Day Median 240 MPN/100 ml Max. Oxidized Wastewater 1/ Sedimentation Between Coagulation & Filtration Processes Filtered Oxidized Wastewater* Coagulated Filtered 5 gpm/sf Turbidity - 2 NTU Average 5 NTU (5%), 10 NTU Max. OR Ultra, Nano, or RO, Membrane Turbidity not-toexceed 0.2 NTU 5% w/i 24 hours, 0.5 NTU Max. Giardia, Virus & Crypto Monitoring & Reporting Disinfected after Filtration CT 450 mg-min/l w/90 min, Modal Contact OR 5-log Virus AND 2.2 MPN/100 ml, 7- Day Median 240 MNP/100 ml Max. Oxidized & Disinfected* 23 MPN/100 ml, 7- Day Median 240 MPN/100 ml Max. Regulation Section Recycled Water Use Level of Treatment Water Quality Requirements Coagulant not required if Influent does not exceed 5 NTU plus backup 1/ Organic matter has been stabilized and contains dissolved oxygen that is non-putrescible and contains dissolved oxygen. 2/ Recycled water as a source of supply for landscape improvements that do not utilize decorative fountains shall be at least disinfected secondary-23 recycled water. FINAL DRAFT Kennedy/Jenks Consultants Cambria Community Services District Recycled Water System Modeling Understanding Recycled Water Regulations June 2003 K/J Figure 3-1

35 Recycled water is addressed as follows: An air-gap separation is required on Premises where the public water system is used to supplement the recycled water supply. A reduced pressure principle backflow prevention device is required on Premises where recycled water is used and there is no interconnection with the potable water system. A double-check valve assembly may be used for Residences using recycled water for landscape irrigation as part of an approved dual plumbed use area established pursuant to Sections through unless the recycled water supplier obtains approval for the local public water supplier, or [DHS] if the water supplier is also the supplier of the recycled water, to utilize an alternative backflow prevention plan that includes an annual inspection and annual shutdown test of the recycled water and potable water systems pursuant to subsection 60316(a) Guidelines To assist in compliance with Title 22, DHS has prepared a number of guidelines for production, distribution, and use of recycled water. Additionally, DHS recommends use of guidelines prepared by the California-Nevada Section of the American Water Works Association (AWWA). These guidelines are summarized below. Guideline for the Preparation of an Engineering Report on the Production, Distribution, and Use of Recycled Water. According to Title 22, prior to implementation of a water reclamation project (production, distribution, or use) an engineering report must be prepared and submitted to DHS. This guideline, prepared by DHS and dated March 2001, specifies the contents of an engineering report. The report should describe the production process, including the treated (effluent) water quality, the raw water quality, the treatment process, the plant reliability features the supplemental water supply, the monitoring program, and a contingency plan to prevent distribution of inadequately treated water. The report should include maps of the distribution system and describe how the system will comply with DHS and AWWA guidelines and Title 17. The report should include maps of proposed use areas and should describe the use areas, the types of uses proposed, the people responsible for supervising the uses, the design of the user systems, and the proposed user inspection and monitoring programs. Manual of Cross Connection Control/Procedures and Practices. This manual, dated July 1981, focuses on establishing a cross-connection control program to protect the public against backflow and back-siphonage of contamination. Main elements of the manual include areas where protection is required; causes of backflow; approved backflow preventers; procedures, installation, and certification of backflow preventers; and water shutoff procedures (for conditions which pose a hazard to the potable water supply). Guidelines for the Distribution of Nonpotable Water. These guidelines were prepared by the California-Nevada Section of AWWA in The purpose of these guidelines is to provide guidance for planning, designing, constructing, and operating non-potable water systems, including recycled water systems. Distribution lines, storage and supply, Final Report Task 3: Recycled Water Distribution System Master Plan Page 20

36 pumping, on-site (user) applications, and system management are discussed. DHS guidelines reference these guidelines. Guidelines for the On-Site Retrofit of Facilities Using Disinfected Tertiary Recycled Water. The California-Nevada Section of AWWA prepared these guidelines in 1997 to provide guidance on modifying existing on-site facilities for conversion to use of recycled water, including recommendations for signage, backflow prevention, and separation standards, for landscape irrigation, agricultural irrigation, industrial uses, and impoundments Emerging Recycled Water Quality Concerns In addition to the existing Title 22 regulations, there are some emerging developments within the water supply industry that are subject of recent discussion. Most noteworthy are the unregulated substances of N-Nitrosodimethylamine (NDMA), 1,4 Dioxane, and trace pharmaceuticals. Although these substances are not currently regulated, they may be in the near future N-Nitrosodimethylamine (NDMA) N-Nitrosodimethylamine (NDMA), is a probable carcinogen and has been linked to various forms of liver cancer. It has a history of use as a research chemical as well as an intermediate compound formed in the production of rocket fuel. Currently, the DHS has set a very low action level of 0.01 micrograms for NDMA. In addition to the low action level, NDMA is also very difficult to measure in low concentrations. NDMA is also suspected as being formed as a disinfection byproduct under certain conditions. To date, research is ongoing on NDMA, and its potential formation. As a result, regulations on NDMA are currently in a state of flux and are subject to change as more information becomes available. During calendar year 2000, groundwater recharge wells using treated wastewater effluent were shutdown in Orange County after the discovery of minute levels of NDMA. To address NDMA concerns, alternative forms of disinfection are being considered due to concerns that chlorine disinfection may increase the potential for NDMA formation. For example, the use of ultra-violet radiation coupled with the addition of hydrogen peroxide has been found effective in reducing NDMA levels 6. At this writing, the fate and transport of NDMA in the natural environment is unknown. It is also unknown whether any minute quantities of NDMA could be found in CCSD effluent. If found in treated effluent, alternative disinfection systems to ensure NDMA is not created, could be necessary ,4 Dioxane 1,4 Dioxane has attracted attention due to it being a known carcinogen, and its use in personal care products such as shampoos. It is also a solvent stabilizer and has been found in groundwater remediation efforts involving trichloroethane (TCA), a cleaning solvent. 1,4 Dioxane may eventually be regulated out of consumer products. However, until such time, wastewater treatment processes, such as advanced oxidation systems, could be required. 6 May 9, Association of California Water Agencies Conference, Monterey, California. Final Report Task 3: Recycled Water Distribution System Master Plan Page 21

37 Trace Pharmaceuticals The discovery of trace pharmaceuticals in the water supplies of Europe and the United States has been drawing much interest among water professionals due to potential health concerns. Trace pharmaceuticals could be the result of outdated medicines being flushed down the toilet, and incompletely metabolized medicines passing as waste. Pharmaceuticals could include hormone supplements, antibiotics, anti-depressants, various stimulants, painkillers, etc. Scientists are at odds over the potential health effects of such minute quantities in water supplies. Concerns have also been raised over the potential impact trace pharmaceuticals could have in the aquatic environment. To date, there are no regulations governing trace pharmaceuticals. Additionally, little information exists on the removal efficiency of wastewater treatment processes. The United States Geological Survey is currently conducting a significant study effort on trace pharmaceuticals as part of its Toxic Substances Hydrology Program. Depending upon the outcome of scientific studies, future regulations could follow governing the treatment and reuse of wastewater as it relates to the removal of trace pharmaceuticals. Final Report Task 3: Recycled Water Distribution System Master Plan Page 22

38 Section 4 Treatment Processes

39 Section 4: Treatment Processes This section presents the recycled water treatment processes. The wastewater pumping, storage, and distribution systems are discussed in Section Title 22 Requirements In order to meet Title 22 regulations, disinfection and tertiary treatment is required for irrigation use in schoolyards and parks as well as for structural fire fighting purposes. Accordingly the existing WWTP must be modified to include these treatment processes. Tertiary treatment consists of coagulation/flocculation, sedimentation, filtration, and disinfection. A number of tertiary filtration systems are available; systems that should be evaluated in more detail in the preliminary design report include the Parkson Dynasand and the Aqua-Aerobic Aquadisk. The Parkson Dynasand system is reliable and provides continuous backwash. The Aqua-Aerobic Aquadisk is relatively small in size, a benefit when space is limited. In addition, the modular US Filter Memcor ultrafiltration system or competing Zenon system could be considered. For a 0.5 MGD tertiary treatment capacity, these systems would have an estimated capital cost of $1 to $3 million (in 2002 dollars) and meet Title 22 regulations. Only water required for recycled water use would need to be treated to tertiary levels, which may save on operation and maintenance costs. CCSD may also consider the use of a membrane bio-reactor (MBR) instead of tertiary filtration. A MBR is a variation on the activated sludge process, currently practiced at the WWTP. The significant difference is eliminating the need for secondary clarifiers, return activated sludge, and tertiary filters. The MBR process consists of applying a vacuum to hollow core, long strand membranes to filter the mixed liquor directly from the aeration basin. Benefits of a MBR include, superior filter removal to typical wastewater tertiary filters and the ability to operate at mixed liquor suspended solids concentrations of 10,000 milligrams per liter. The primary limitation of an MBR system is the flux rate of effluent through the membranes. Accordingly, the facility should be designed with adequate capacity to meet peak hydraulic flows, detention time, and solids retention time. Additionally, to keep the solids from ultimately plugging the microfilter membranes, each membrane module has a compressed air connection. The air scours the long-stranded membranes, keeping them in constant motion. For in-place backwashing, a hypochlorite solution, diluted with the high quality MBR effluent, may be periodically back pulsed through the membrane. The backwash material is absorbed into the mixed liquor with no impact on the activated sludge organisms. Several manufacturers, including Zenon, U.S. Filter, and Enviroquip, produce MBR systems which have been approved for Title 22 recycled water use. Unlike a tertiary filtration, a MBR system would treat the entire influent flow, which may lead to increased operational costs. A MBR system has an estimated capital cost of $5 to $6 million (in 2002 dollars), assuming no other treatment upgrades are required (e.g., additional grit screening to prevent membrane clogging). 4.2 Potential Additional Processes Due to emerging concerns regarding nitrate, total dissolved solids (TDS), NDMA formation, and trace pharmaceuticals, CCSD had Kennedy/Jenks consider implementing additional processes that would treat WWTP effluent beyond current regulatory requirements. Additional processes Final Report Task 3: Recycled Water Distribution System Master Plan Page 23

40 to be considered include dentrification, nanofiltration (a low pressure reverse osmosis process) and advanced oxidation using hydrogen peroxide with ultraviolet light irradiation. This approach would also ensure there is no potential degradation to groundwater or surface water in the vicinity of any larger landscape irrigators using recycled water Dentrification Although not required under Title 22 regulations, a dentrification process would aide in addressing concerns regarding impacts of increasing nitrate concentrations on habitat and water quality within the watershed. Dentrification would be achieved by adding an anoxic zone upstream from the MBR, microfiltration, or tertiary filtration. This would be done by the addition of baffling to the aeration basin, creating oxic and anoxic zones. Although the existing aeration facilities have the necessary provisions for baffle insertion, modifications to the aeration control may be required Nanofiltration (low pressure reverse osmosis) Due to recent modifications to the WDR Order issued by the RWQCB, the need for additional salt management has emerged. To ensure levels of TDS are kept at or below background levels, further demineralization of the recycled water could be achieved by the including a nanofiltration (low pressure reverse osmosis [RO]) membrane system downstream of filtration. A low-pressure RO membrane could significantly reduce TDS and salt concentrations and thus reduce concerns regarding impacts to water quality resulting from the use of recycled water. Because the TDS concentration is much lower in recycled water than in seawater, the amount of energy needed to reverse the osmotic force is also much lower. Additionally, nanofiltration membranes have less hydraulic head loss than typical seawater membranes adding further energy savings. A 0.5 MGD low-pressure reverse osmosis system would have an additional capital cost of $2 to $3 million (in 2002 dollars), not including the cost for brine disposal. Concerns for increased TDS and salt loading may also be addressed by the proposed Seawater Desalination facility. The Seawater Desalination facility would provide high-pressure RO treated seawater for potable use. This would eliminate the need for in-home softening units as well as reduce the overall TDS concentrations in the WWTP influent, thereby reducing the salt loadings in the WWTP effluent. The Seawater Desalination facility is further discussed in the Task 4 report Advanced Oxidation (hydrogen peroxide and ultraviolet light irradiation) The combination of hydrogen peroxide and ultra-violet light irradiation has been developed as a means to oxidize and destroy organic molecules. Trace pharmaceuticals and NDMA are examples of organic molecules that are not currently regulated, that could be destroyed using advanced oxidation. Although neither of these is known to exist in the WWTP effluent, for cost estimating purposes, the use of advanced oxidation is being assumed. Although, CCSD can reliable meet Title 22 requirements for disinfection utilizing their existing sodium hypochlorite facilities, CCSD may further benefit from the use of Ultraviolet (UV) light irradiation as the primary disinfectant. UV light irradiation would provide an efficient disinfection, minimize hazardous chemical storage and handling, and utilize a smaller size facility than Final Report Task 3: Recycled Water Distribution System Master Plan Page 24

41 chlorination. Sodium hypochlorite would still be used to maintain a disinfection residual in the storage tank and distribution system. Although, UV light lamps need to be periodically cleaned to maintain their efficiency, operational costs would decrease due to the reduction in sodium hypochlorite usage. There are two main configurations available: (1) open channel, and (2) in-pipe. With the open channel option, the UV lamps are installed in an open channel. The wastewater flows over the lamps and is disinfected. With the in-pipe option, the lamps are installed inside a pipe. The open channel option is more common and allows for more direct inspection, removal, and cleaning of the lamps. Also, there are more manufacturers for the open channel option than the in-pipe option. However, it does require installing an open channel, which will take up more space and is more costly than the in-pipe option. Therefore, the in-pipe option is the preferred configuration. However, currently there are no in-pipe manufacturers certified to meet the DHS s requirements for Title 22. One manufacturer, Aquionics, expects to receive their certification within the next several months. Several other manufacturers, including Wedeco, Trojan, and Suntec, are certified by the DHS for open-channel UV. The capital cost for a 1.0 MGD UV disinfection system is approximately $1 million (in 2002 dollars). Final Report Task 3: Recycled Water Distribution System Master Plan Page 25

42 Section 5 Development of the Recycled Water System

43 Section 5: Development of the Recycled Water System The previous section described the treatment plant improvements necessary to meet effluent quality concerns for recycled water use. This section describes the development of the recycled water system based on the demands developed in Section 2. The modeling software utilized to evaluate CCSD s recycled water system is H 2 0NET version 3.1 from MWH Soft, Inc. 5.1 Recycled Water System Model Guidelines A preliminary recycled water system was developed based upon the potential recycled water users discussed in Section 2. Utilizing AutoCAD 2000i and H 2 0NET Analyzer Version 3.1, a plan-view preliminary layout of the recycled water distribution system was developed. The model development was performed in accordance with the following guidelines: Model nodes were placed at pipeline intersections, and near potential service connections. Baseline pipe sizes and lengths are as listed in Appendix C. This table provides the pipe number, which corresponds to the hydraulic model, lengths and pipeline diameters. Elevation data for the model nodes was obtained from the Geographic Information System (GIS) layer contours (5 ft contour intervals) that was provided by Spacegraph. Node demands were assigned in accordance with the discussion in Section 2. Model pipe elements were constructed for recycled water main piping. Hazen-Williams C-factors for all piping were set to the model specified setting of 130 to represent new pipeline roughness. This is an assumed value typically based on the age of the pipe, pipe material, soil characteristic, and detected/known growth on pipe-lining. All potential tanks, pump stations and pipelines were included in the model. There is an existing reach of approximately 1,000 feet of 8-inch diameter pipeline in Moonstone Beach Dr. This pipe was included in the model. The proposed preliminary recycled water distribution piping, hydraulic model nodes, and pressure zone delineations are shown as Figure Recycled Water Demand Scenarios Demands developed in Section 2 were incorporated into the model by assigning calculated demands to the junction node located nearest geographically. The average demands were incorporated into the model and peaking factors were applied to obtain the following water demand scenarios: Average Daily Demand (ADD) Maximum Daily Demand = 2.7 * ADD Final Report Task 3: Recycled Water Distribution System Master Plan Page 26

44 Legend Pipe Diameter 4" 6" 8" 18"! Recycled Water System Nodes! 54! 58! 56 Northern Pressure Zone/ Cantex WWTP Tank Area! 40 10!!!! Wastewater Treatment Plant Pump Station ("Cantex" Tank Location) Zone 1 Tank Site & Zone 2 Booster Pump Station! 14! 12!! 18 16! !!!! !!! 22! 20 38! 30!!! Santa Lucia Middle School Relocated Pine Knolls Tank Southern Pressure Zone/ Santa Lucia Tank Area New Grammar School 34! µ Not To Scale Cambria Community Services District Recycled Water System Modeling Proposed Recycled Water System Layout K/J Figure 5-1

45 Peak Hour Demand = 5.76 * ADD Maximum Day Demand Plus Fire Flow A scenario incorporating fire flow was included because CCSD s service area has many structures located within pine forests. The long urban wildland fire interface that exists, along with related concerns by the Cambria Fire Department, led to a recycled water-modeling scenario that includes fire flow. By over-sizing the recycled water system, an additional level of fire protection may be possible. Fire flow demands were developed in consultation with the recommendations of CCSD s Fire Chief and District Engineer and were a primary focus of the companion Task 3, Potable Water Distribution System Report. 5.3 Recycled Water System Model Development In development of the recycled water distribution system, the need for pipelines, storage tanks, and pump station was identified. The following is a description of each of the required facilities Recycled Water Distribution System There are two different systems that were modeled for evaluation, a system designed to meet peak hour flow and a system designed to meet fire flow demand at maximum day flow. The differences between these systems are reflected in the pipeline diameter and pump station and reservoir sizing. The routing of the pipelines and locations of pressure zones, pump stations and reservoirs remains the same Pipelines There are approximately 25,600 feet of pipeline in the recycled water system model. For fire flow conditions, all of these pipes are required to be a minimum of 18-inches in diameter to meet the pipe design criteria since there are no hydraulic loops in the system. To meet peak hour demands without fire flow, 6 inch diameter pipes are required. The modeled recycled water system pipelines are shown in Figure Storage Tanks Recycled water distribution system storage is necessary provide flow to users during periods of high demand. Since pressure to recycled water users is a function of elevation, tank storage should be placed at a site that will provide optimal pressure to the majority of the users. For hydraulic purposes, the recycled water reservoir should be located high enough to provide at least 50 psi of static pressure while also being reasonably close to the main distribution pipeline grid. From review of various potential sites, the area behind the Santa Lucia Middle School (elevation 250+/-) was determined as the most feasible storage tank location. This location will serve by gravity the majority of proposed recycled water customers with the exception of the Middle School, the Cambria nursery, and the new grammar school. Because Cambria is currently replacing its existing potable water system s Pine Knolls storage tanks with a larger tank system, the existing Pine Knolls tanks were considered for reuse as recycled water tanks on the middle school site. Additionally, the CCSD has an out of service package treatment plant (a.k.a., the old Cantex treatment plant) at its WWTP that could be converted to tank storage. Therefore, the old Cantex plant is being considered as a clear well storage tank for Final Report Task 3: Recycled Water Distribution System Master Plan Page 27

46 storing highly treated plan effluent prior to pumping into the distribution system. Tank storage locations are shown on Figure 5-1. Pump Stations There are two pump stations that are included in the model. The first pump station is at the CCSD s WWTP. This pump station will take water from the treatment plant and pump to the Santa Lucia site. The pump station is sized to meet a maximum day demand of 350 gpm. The second pump station will draw water from the Santa Lucia gravity storage tanks and boost it in pressure into a hydro-pneumatic pressure tank system. The hydro-pneumatic system will serve the upper pressure zone customers; primarily the Santa Lucia Middle School site, the Cambria nursery, and the new grammar school. The pump station at the Santa Lucia site is designed to handle peak hourly demands to the upper pressure zone, or approximately 300 gpm. The pump station locations as described in reference to tank sites are shown on Figure 5-1. Final Report Task 3: Recycled Water Distribution System Master Plan Page 28

47 Section 6 Results of the Recycled Water System Analyses

48 Section 6: Results of the Recycled Water System Analyses This section presents the criteria used to evaluate the adequacy of the proposed recycled water system and the results of the hydraulic analyses using the recycled water system model described in the previous section. Results of the model were based on the development of both likely and less likely sites assuming a conventional irrigation system and include the potential future recycled water users. 6.1 Evaluation Criteria A discussion of the evaluation criteria used to determine the recycled water system needs for pipelines, reservoirs, and pumps stations is given below Pipelines Evaluation criteria include system pressure, velocity and flow requirements for distribution system pipelines. These criteria were established to evaluate potential customer service issues such as excessive/low pressures, plumbing leaks, or excessive wear and pumping due to high headlosses or lost energy in the system. However, since recycled water systems are primarily used for irrigation, higher service pressures than those for potable water systems are allowable. At high flow rates, velocities can approach levels that are physically destructive to pipelines and valves. Evaluation criteria were developed through a review of industry standards and from completed and approved reclaimed water master plan projects of a similar nature. The water service pressure criteria used for these analyses are: Desired minimum pressure at peak hour demand: Desired minimum pressure at maximum day with fire flow: (This allows for a 4 psi drop from the main to the hydrant so that fire flow can be delivered at 20 psi.) Desired maximum service pressure: 50 pounds per square inch (psi) 24 psi 150 psi The velocity requirements used for these analyses are as follows: Desired maximum velocity at maximum day: Desired maximum velocity at maximum day with fire flow: 7 feet per second (ft/s) 15 ft/s The fire flow criteria used for these analyses are as follows: 4,500 gpm at no less than 24 psi for 4 hours during maximum day conditions. This reflects flow for a commercial structure fire or school fire in the East or West Village commercial areas. Commercial fire flow criteria were adopted for the entire recycled water system since it is located in predominantly commercial zones. Final Report Task 3: Recycled Water Distribution System Master Plan Page 29

49 6.1.2 Recycled Water Distribution System Storage Tanks Storage of water to serve recycled water customers is required for two basic purposes: Operational storage = 1 maximum day s demand Fire storage The reliability standard is lower than for a potable water system which provides an additional emergency storage component typically equating to 30% of 1 day s maximum day demand. Therefore, meeting the one maximum day demand for operational storage for the recycled water storage system may not be necessary due to it being used only for irrigation. Maximum day demand was used however, as this is the most conservative assumption. If pumps were adequately sized & operating, the storage volume could be reduced below one maximum day demand Operational Storage Reservoir capacity is used to provide additional water storage to serve demands in excess of the capacity of the recycled water supplied from the WWTP. In the case of peak hour demand conditions, the reservoir is sized to accommodate one 24-hour period of maximum day demand (or 20 hours of maximum day demand and two peak demand events) in case of an emergency. This would allow limited irrigation use of the system without providing fire flow support Fire Storage Storage for firefighting purposes should be provided to meet fire flow and duration demands without the necessity of transferring water storage from a lower pressure zone to a higher one. The amount of fire storage desired by CCSD was developed in consultation with the recommendations of CCSD s Fire Chief. The fire flow and duration requirements under these recommendations are based on land use and are presented in the previous subsection. For maximum day plus fire flow conditions, the storage capacity required was determined by calculating the amount of water needed during a 4-hour fire flow event in either service zone. Storage provided under this condition accounts for one 24-hour period of maximum day demand for both service zones plus fire flow support Pump Stations Inter-zone pump stations are necessary to convey water from lower pressure zones to higher pressure zones. If gravity storage is not available in the higher-pressure zone, pump stations should be capable of providing the larger of the zone s peak hour demand or maximum day demand plus fire flow. If adequate storage is available but the higher zone is served by a single reservoir, pump stations should be capable of providing the zone s peak hour demand so that the reservoir can be periodically removed from service. If the higher zone is served by multiple reservoirs, pump stations should be capable of providing the zone s maximum day demand. Final Report Task 3: Recycled Water Distribution System Master Plan Page 30

50 6.2 Critical Conditions for Modeling The recycled water system model was run under a variety of normal and emergency operating conditions. Normal conditions included average day, maximum day, and peak hour demands. Emergency conditions included a fire flow scenario during maximum day demands. Fire flow scenarios parameters were provided by CCSD staff. Of these modeled operating conditions, the following were identified as critical conditions for the purpose of evaluating recycled water system design: Peak hour demand for potential recycled water users Commercial (4,500 gpm) fire flow during maximum day demand 6.3 Results of Hydraulic Analyses Hydraulic analyses of CCSD s recommended recycled water system were performed using the hydraulic model as described in Section 5. Because the model utilizes topographic contours from CCSD s GIS system, small pressure variations between those resulting from the model and those resulting from field measurements should be expected. Results from the hydraulic analyses for critical conditions are discussed in the following subsections Peak Hour Demand for Recycled Water System A peak hour demand scenario was evaluated for the future recycled water system, assuming development of all existing and future recycled water users. For this scenario, all areas of the system had pressures within the desired 50 to 150 psi range, with the exception of the high elevation area near the Santa Lucia Tank/booster pump site. This system is proposed to be serviced by the booster station as a hydropneumatic zone. Included within this hydropneumatic zone is the future grammar school. With the hydro-pneumatic system, the lowest system pressure was 49 psi located at Future Grammar School site. The areas of high pressure were primarily located in the northern pressure zone due to lower service elevations and the proximity to the WWTP booster station. Outside of the treatment plant area, the highest system pressure was 52 psi located at Shamel Park. The node identifications, locations, and residual pressures are summarized in Appendix D and shown as Figure Commercial Fires During Maximum Day Demand The recycled system model was evaluated for fire flow by applying the fire flow demand to nodes and running the model to determine if the system could convey the required flow. For fire flow conditions, all pipes are required to be a minimum of 18-inches in diameter to meet the pipeline design criteria due to the lack of hydraulic loops in the system. 6.4 Storage Tanks Based on the established evaluation criteria for the storage tanks and discussions with CCSD staff regarding storage distribution, the tank capacities were determined. Results of this evaluation are presented in Table 6-1. For maximum day plus fire flow demand conditions, 1.5 MG of tank storage is required. To meet Peak hour demand, 0.4 MG of tank storage is necessary. The potential for rehabilitating and/or refurbishing existing tanks may alleviate the need for significant additional recycled water storage. An evaluation of existing tank reuse will be discussed in Section 7 of this Report. Final Report Task 3: Recycled Water Distribution System Master Plan Page 31

51 TABLE 6-1 EVALUATION OF TANK STORAGE Average Maximum Total Total Total Daily Daily Required Existing Storage Demand Demand Storage Requirements (MG) Storage Storage Deficit Tank Storage and Zones Served (MGD) (MGD) Operational Fire (MG) (MG) (MG) Without any Existing Storage Fire Flow Zones 1& Peak Hour Zones 1& With Reuse of Pine Knolls Tanks Only Fire Flow Zones 1& Peak Hour Zones 1& With Use of Cantex Tank Only Fire Flow Zones 1& Peak Hour Zones 1& With Reuse of Pine Knolls Tanks and Cantex Tank Fire Flow Zones 1& Peak Hour Zones 1& Final Report Task 3: Recycled Water Distribution System Master Plan Page 32

52 6.5 Pump Stations Based on the established criteria, the capacities for the new recycled water pump stations were evaluated. The results of this evaluation are presented in Table 6-2. The proposed recycled water system pump stations are located on Figure 5-1. TABLE 6-2 EVALUATION OF PUMPING CAPACITY Tank Storage Serving Zone Peak Hour Demand (gpm) Fire Flow (If Pressure Zone is not Served by Gravity Storage) (gpm) Required Pumping Capacity (gpm) Pump Station Region Served With Fire Flow WWTP Zone 1 & Santa Lucia 2, Santa Lucia Booster New Grammar School Without Fire Flow WWTP Zone 1 & Santa Lucia 2, Santa Lucia Booster New Grammar School Final Report Task 3: Recycled Water Distribution System Master Plan Page 33

53 Section 7 Recommended Recycled Water System

54 Section 7: Recommended Recycled Water System The previous section presented the results of hydraulic analyses using a model developed for CCSD s proposed recycled water system. This section discusses the recommended facilities to meet the hydraulic requirements. 7.1 Basis for Evaluation of Recommended Improvements The previous section of this report presents the results of hydraulic analyses under critical operating conditions. These critical conditions are based on the level of service and fire protection that is provided by the recycled water system. Peak Hour Demand. Under this condition, the recycled water system would meet normal operating demand and provide undefined and variable levels of fire protection. Commercial Fire Event During Maximum Day Demand. These conditions represent maximum day demand combined with commercial fire protection (4,500 gpm for 4 hours). Based on these critical conditions, the evaluation of recommended improvements presents the improvements necessary to meet peak hour demands and the improvements necessary to provide fire protection. 7.2 Basis of Preliminary Cost Estimates The construction costs provided in this section are based upon developed unit costs for pipelines, tanks and pump stations. These cost estimates are provided at a preliminary planning level of accuracy and do not assure that a bid price will be received at or below this estimate, as price bids are subject to many variables. All unit costs represent installed costs, including taxes (8.25 percent on materials only), contractor overhead and profit (18 percent), engineering (20 percent), legal/administration (2 percent), construction management (15 percent), and contingency (20 percent). Costs do not include land acquisition or right-ofway. The pipeline construction cost estimates for proposed improvements were developed based upon materials costs, RS Means Building and Construction Cost Data 2002, and engineering judgment. Reservoir and pump station costs estimates were based upon actual construction costs for similar facilities. Costs and cost estimates were adjusted using the ENR Construction Cost Index 20-city national average. To be consistent with the Task 3 potable water distribution system analysis report and the Task 4 long-term supply report, the July 2002 ENR Index of 6605 was used Treatment Plant Improvements As discussed in Section 4, the existing WWTP would require the addition of tertiary filtration to meet the requirements of Title 22 for irrigation use of recycled water at community parks and schools. The cost estimate only includes the treatment required to meet Title 22 and does not include additional processes which may be added to address emerging concerns. The plant Final Report Task 3: Recycled Water Distribution System Master Plan Page 34

55 improvements were sized to accommodate the maximum daily demand (0.5 MGD). The estimated capital cost in mid-2002 dollars is provided in Table 7-1. Due to the higher capital cost of the MBR system, it is recommended that CCSD incorporate a tertiary filtration system. TABLE 7-1 ESTIMATED COST FOR TREATMENT PLANT IMPROVEMENTS (MID-2002 DOLLARS) Treatment Unit Capital Cost ($) Tertiary Filtration $1,000,000 - $2,000,000 MBR System $2,000,000 - $3,000, Pipelines Preliminary cost estimates for pipelines are based on the unit costs for both ductile iron pipe (DIP) and polyvinyl chloride (PVC) as summarized in Table 7-2. Pipeline unit costs assume instreet construction with a moderate number of utility crossings and include valves, traffic control, and road resurfacing. System flushing and testing costs assume that approximately 1,000 feet of pipeline per day are treated. For DIP, the cost for purple polyethylene wrapping is included; for PVC pipe, the cost for purple pipe has been added. TABLE 7-2 PIPELINE UNIT COSTS (MID-2002 DOLLARS) Capital Cost Pipeline per LF ($) 36" DIP " DIP " DIP " DIP " DIP " DIP " DIP " DIP 120 8" DIP 100 6" DIP 83 24" PVC " PVC " PVC " PVC " PVC " PVC " PVC 92 8" PVC 72 6" PVC 62 Final Report Task 3: Recycled Water Distribution System Master Plan Page 35

56 7.2.3 Storage Tanks Tank unit costs include grading, materials, labor, and testing and are derived from the cost curve that was developed from recent above ground welded steel reservoir construction costs. The cost curve is summarized in Table 7-3. For capital costing calculations, contingency costs of 30% and Engineering & Administration costs of 25% of total construction costs have been added to the unit cost of each proposed facility. TABLE 7-3 RESERVOIR UNIT COSTS (MID-2002 DOLLARS) Storage Capacity (gallons) Capital Cost (mid-2002 dollars) 400,000 $620, ,000 $680, ,000 $750, ,000 $810, ,000 $880, ,000 $920,000 1,000,000 $1,000,000 1,100,000 $1,090,000 1,300,000 $1,260,000 1,500,000 $1,425, Pump Stations Pump station costs include materials, equipment, labor, and testing. Costs are based on the construction of new pump stations and include materials, equipment, labor, and testing. For capital costing calculations, contingency costs of 30% and Engineering & Administration costs of 25% of total construction costs have been added to the unit cost of each proposed facility. Cost curve values for pump station construction are summarized in Table 7-4. TABLE 7-4 PUMP STATION UNIT COSTS (MID-2002 DOLLARS) Power (hp) Estimated $/hp 40 4, , , , ,800 Pumping energy and O&M costs are considered in the capital costing portion of this Plan and annualized by acre-ft delivered in Table 7-8 below. Final Report Task 3: Recycled Water Distribution System Master Plan Page 36

57 7.3 Recommended Recycled Water System Pipelines The cost estimates for approximately 25,000 feet of proposed pipelines for both maximum day plus fire flow and peak hour demand conditions are presented in Table 7-5 and shown in Appendix E. For capital costing calculations, contingency costs of 30% and Engineering & Administration costs of 25% of total construction costs have been added to the unit cost of each proposed facility. TABLE 7-5 PROPOSED PIPELINE COSTS (MID-2002 DOLLARS) Demand Scenario Pipe Diameter (inches) Pipe Length (feet) Cost for DIP Pipe Cost for PVC Pipe Max Day plus Fire Flow 18 25,000 $7,957,235 $6,676,315 Total Peak Hour 6 to 18 25,000 $3,778,125 $2,888,735 Peak Hour 6 20,000 $2,580,750 $1,927,735 Peak Hour 8 2,400 $367,350 $264,585 Peak Hour 18 2,600 $830,025 $696, Recommended Storage Storage for the recycled water distribution system is proposed at two locations: 1) the Santa Lucia Middle School site; and, 2) the WWTP. Seasonal storage to offset potential habitat impacts is assumed to occur below grade in the vicinity of the WWTP percolation pond areas. A cost estimate for seasonal storage to off-set basin demand increases is provided in this section. It is assumed that fire storage will be planned for and provided by the potable water system. Therefore, the recommended storage requirements were based on the peak hour evaluation criteria, which establishes one maximum day s recycled water demand as the basis for storage calculations as explained below. All subsequent storage recommendations and capital costs are based on this criteria and the assumptions regarding use of existing storage reservoirs as follows. Among the scenarios evaluated was the reuse of the existing Pine Knolls tanks by way of relocating to the Santa Lucia Middle School location and reconfiguring the 2 existing tanks to 3 shorter tanks to reduce their visual impact and make them more resistant to seismic forces. Discussions with CCSD staff and Paso Robles Tank representatives have demonstrated a cost benefit in reusing these Pine Knolls tanks for storage at the Santa Lucia School site. Based on the established evaluation criteria for the reservoirs, the capacity of the Pine Knolls reservoirs was evaluated and additional storage requirements were addressed. CCSD staff is also evaluating a rehabilitation effort at the Cantex WWTP and anticipates the availability of an additional 0.40 MG in storage from the refurbished Cantex Tank site Operational Storage For peak hour demand conditions, 0.4 MG in tank storage is required to meet pressure requirements at all service nodes while the system is experiencing one day of maximum day Final Report Task 3: Recycled Water Distribution System Master Plan Page 37

58 demands. Reuse of the Pine Knolls reservoirs reduces storage requirements in this zone to 0.2 MG. To meet fire flow storage criteria, a proposed 1.5 MG reservoir is required. With District reuse of the existing Pine Knolls reservoirs for storage, the size of the proposed reservoir decreases from 1.5 MG to 1.3 MG. An additional alternative to augment storage considers using the old Cantex WWTP Tank for added storage. As shown in Table 6-1, this will provide 0.40 MG when the District has completed with rehabilitations, including roofing of this site. Costs associated with using various tank storage options are shown below in Table 7-6. It is recommended that the CCSD proceed with its plans to reuse tank storage as it has shown to be cost beneficial, while providing adequate storage for the proposed recycled water system under the peak hour criteria (one maximum day s demand). If fire flow were a consideration for the recycled system and tank reuse is considered, then CCSD would require an additional 1.0 MG of storage. The estimated capital cost of the recommended reservoirs including the cost of moving the Pine Knolls reservoirs and refurbishing the Cantex Tank Site is presented in Table 7-6. TABLE 7-6 ESTIMATED RESERVOIR COSTS Estimated Capital Cost Reservoir (mid-2002) dollars Without Existing Storage 1.5 MG for fire flow $1,425, MG for max day $620,000 With Reusing Pine Knolls Only 1.3 MG for fire flow (a) $1,270, MG for max day (a) $400,000 With Using Cantex Tank Only 1.1 MG for fire flow $1,090, MG for max day (b) $0 With Reuse of Pine Knolls AND Cantex Tanks 0.92 MG for fire flow $920, MG for max day (c) $100,000 For Seasonal Storage Requirements Subterranean Storage $600,000 Notes: a Includes the cost of relocating the Pine Knolls Reservoirs estimated to be $100,000 by Paso Robles Tank plus the cost for a new 0.2 MG tank. Recent dive tests conducted by the District have indicated the presence of lead based coating to be minimal and negligible when considering costs for relocating and reconstructing. b Storage deficit is negligible to assign associated costs. Distribution system will accommodate the need for storage using valve adjustments, off-peak pumping to different storage source, etc. c Includes the cost to relocate the two Pine Knolls Tanks. Final Report Task 3: Recycled Water Distribution System Master Plan Page 38

59 7.4.2 Seasonal Storage As discussed in Section 2, CCSD may need to provide seasonal storage to off-set an increase in Basin demand as well as provide sufficient supply during dry months. For purposes of this report, subterranean storage is recommended because it would provide sufficient storage to accommodate the increase in basin demand from the future community park, if the park is developed prior to a new long-term potable water supply. Table 7-6 provides a cost estimate for the subterranean storage facility. Construction costs are anticipated to be between $10 per square foot. Assuming walls that total 2,000-feet in length and 30-feet in depth, the estimated capital cost (2002 dollars) is approximately $600, Recommended Pump Stations Improvements This recycled water system proposes use of two pump stations to meet peak hour demands. The first pump station is located at the existing Cantex WWTP and should be sized to meet peak hour demands for Zones 1 & 2. The pumps will deliver capacity to fill the Santa Lucia tank for serving Zone 1 and provided adequate capacity for the second pump station, located at the Santa Lucia tank site, to deliver the peak hour demand to the proposed New Grammar School tank to serve Zone 2. Maximum day plus fire flow criteria was considered as well, for conservative purposes, and the most conservative capacity for a commercial fire has been included in the Cantex WWTP to deliver to the Santa Lucia tank site for emergency purposes to Zone 1. Peak hour and fire flow support may be provided by the reservoir at the Santa Lucia site. Recommended pump station costs are shown in Table 7-7. TABLE 7-7 ESTIMATED PUMP STATION COSTS Pump Station Pump Station Capacity Demand Scenario Description (gpm) Cost Max Day plus Fire Flow WWTP Pump Station 700 $300,000 Max Day plus Fire Flow Santa Lucia Booster 4,750 $1,055,000 Total Max Day plus Fire Flow $1,355,000 Peak Hour WWTP Pump Station 700 $300,000 Peak Hour Santa Lucia Booster 300 $150,000 Total Peak Hour $450, Estimated Recycled Water System Costs The estimated recycled water system costs for both demand scenarios are presented in Table 7-8. Although sizing has been discussed for fire flow criteria, costing is shown only for those facilities required for peak hour criteria as the Task 3: Potable Water System Modeling Final Report Task 3: Recycled Water Distribution System Master Plan Page 39

60 report, performed in parallel with this Report, considers capital costs for pipeline, storage, and pump sizing with fire flows as the driving criteria. For peak hour demand without fire flow, estimates are given for all new storage and for use of both the Pine Knolls and Cantex tanks. These reservoir options were selected because they were feasible, cost-effective, and met with CCSD planning requirements. Treatment plant improvement cost consists of the cost for the addition of a tertiary filtration system only. A midrange capital cost was used between the estimated $1M to $2M, to add a reasonable level of conservatism. Annual O&M costs were estimated by evaluating power costs, parts costs, and labor costs. Table 8-25 provides a summary of the total capital and annual O&M costs. TABLE 7-8 ESTIMATED O&M COSTS (2002) FOR RECYCLED WATER Description of Cost Est. Capital Cost (PVC pipe) Fixed O&M Cost Pipeline (a) $2,888,700 $2,800 Pump Station (b) $450,000 $4,500 Reservoir (a) $100,000 $100 Seasonal Storage (a) $600,000 $600 Treatment $1,500,000 Labor (c) $26,500 Total ($/Yr) $5,538,700 $34,500/Yr. Variable O&M Costs (AFY) Treatment costs (d) $408 Power costs (e) $405 Total Variable ($/AF) $812 Notes: (a) Evaluated at 0.1 percent of capital cost. (b) Evaluated at 1.0 percent of capital cost. (c) Evaluated at 3 hrs/day at $34/hr, including benefits, and 260 days a year. (d) Evaluated at 5.0 percent of capital cost, including chemical cost, in AFY (e) Evaluated using an electricity rate of $0.15/kW-hr and 365 days of operation. This includes the power cost for both pump stations. A pump efficiency of 80 percent and a motor efficiency of 90 percent were assumed. The total annual fixed cost is $355,000 and the total variable cost is $810 per AF. Total Annual Fixed Cost ($/Yr) Total Variable Cost ($/AF) (b) Supply Annual Capital Costs Capital Cost (a) Fixed O&M 185 AFY $5,538,700 $320,000 $34,500 $354,500 $810 Notes: (a) Calculated using a 4 percent interest rate and a 30-year life span. (b) Rounded to the nearest $10/AF. Final Report Task 3: Recycled Water Distribution System Master Plan Page 40

61 Section 8 Recommended Implementation Plan

62 Section 8: Recommended Implementation Plan The previous section identifies recommended facilities to convey recycled water to meet demand and to provide fire protection. This section presents an implementation plan for the recommended facilities based on established priorities. A phasing plan and implementation schedule are recommended. 8.1 Implementation Considerations In order to implement each phase, several development activities need to occur and issues need to be addressed. Many of the implementation elements apply to all the phases; however, some issues are unique to individual phases or facilities. The following is a listing of the major activities and issues to be addressed which are common to all phases. The activities are generally listed in order of occurrence; however, most would require concurrent effort through the duration of implementation. Customer Development - Verify demands, customer commitment, connection locations, retrofit requirements, and DHS approvals. Preliminary Design/Engineering Feasibility - Evaluate alternative pipeline routes, collect detailed utility and traffic information, prepare updated cost estimates, and update with new information from customer development activities. Preliminary design can be initiated following initial verification of customer information, provided updated customer information does not identify other significant issues. Regulatory Approvals - Identify required permits and regulatory approvals, including DHS, RWQCB, CEQA, and construction permits. Develop management plan and schedule to obtain regulatory approvals, considering appropriate review periods for regulatory agencies. Regulatory activities should be initiated concurrently with preliminary design and continue through implementation and operation. Design/Construction - Incorporate any updated customer information, regulatory requirements, and community concerns. Reevaluate economics with updated information and design level cost estimate. Design and construction efforts can begin immediately following preliminary design. Training Provide training and guidance to the site supervisors assigned by each recycled water user. Educate site supervisors on the proper use of recycled water, recycled water regulations, and basic principles of backflow prevention and crossconnection control. 8.2 Phasing Plan Because the recycled water system can only be utilized when complete, only one implementation phase is recommended. However, this recommendation should be reviewed if concerns arise from the use if recycled water at the future sites. Final Report Task 3: Recycled Water Distribution System Master Plan Page 41

63 CCSD may consider dividing the project into two bidding packages: one for the distribution system and one for the treatment plant improvements. This approach would take advantage of different contractor specialties and could result in lower construction cost. Accordingly, it is recommended that this approach be evaluated during preliminary design. 8.3 Implementation Schedule Implementation of the recycled water system described previously is anticipated to take 2.5 to 3.5 years to complete. Although relatively straightforward, negotiations with potential recycled water users may take up to 6 months and should begin as early as possible. Opportunities for state and federal funding should also be pursued early in the process. Permitting, design, construction, and startup are likely to require 2 to 3 years to complete. The permitting process may also be lengthy due to numerous Title 22 requirements and should also begin as early as possible. The implementation schedule is presented in Figure 8-1. Final Report Task 3: Recycled Water Distribution System Master Plan Page 42

64 Task Name Instutional Argeements Figure 8-1 Implementation Schedule CCSD Recycled Water System Modeling Report... r... r... T r... r... r r Year 1 Year 2 Ye Qtr 1 Qtr 2 Qtr 3 Qtr 4 Qtr 1 Qtr 2 Qtr 3 Qtr 4 Qtr 1 Qtr 2 I Preliminary Design Permitting I Design Bid/Award Construction Project: Figure8-1 Date: Tue 8/17/04 Task Split '"'"'"'"'"'"'"'"'"'"'"'"' Progress Milestone I Summary Project Summary G:\PROJECTS\2002\ \DRAFTREPORT\Figure8-1.mpp Page 1 External Tasks External Milestone Deadline

65 Appendix A Evaporative Control Systems, Inc. (ECS) Information

66 How to Install - Garden Beds - Turf Many people would be surprised to know that the vast majority of water provided through traditional sprinkler systems end up in the neighborhood gutter or floating back up to the skies. The ECS system is based on a revolutionary but surprising simple concept. Provide an extremely efficient way to collect all water, and store it safely below the ground. Here's how it works. A subsurface irrigation system is installed below the surface of the lawn or garden. Any runoff water (from rain gutters and drains is funneled to a storage reservoir below the ground). Plants, flowers and lawn are then watered from below the surface of the ground. The end result is an extremely efficient system of irrigation. The benefits: No more broken sprinkler heads, and wasted water. A dramatic decrease in the amount of water needed to irrigate lawns and gardens. Healthier, happier plants and flowers Eliminates the needs for troublesome and in some cases, dangerous, sprinkler heads. Ability to fertilize from below the ground! n:\gis-proj\2002\ ccsd master plan\final recycled water mp\appendix a1.doc

67 How to Install - Garden Beds - Turf Here is the more scientific explanation of the ECS subsurface irrigation and drainage system: The Capillary Zone Ten to 12" above the 3" deep saturated zone reservoir lies the Capillary zone that provides an ideal matrix for root growth. A water film is constantly available around the sand grains, with the remaining void space occupied by air (oxygen). Root hairs during the growth phase prefer this environment to initiate water and nutrient absorption, and soil microorganisms prefer this aerobic environment for eventual decomposition of dead organic matter. The Transpiration Zone For a larger view of this slice view, click here. This overlapping layer extends from the tip of the deepest root in the capillary zone to the top of the highest leaf tip of any growing plant. This is the active pumping action system within the plant that not only delivers water and nutrients to all plant tissue during the growth phase, but also regulates plant health by regulating the turgor pressure and temperature within the leaf through evaporation. The rate of transpiration is directly proportional to the surface area of the plant, the growth rate of the plant, the ambient temperature, wind velocity, and humidity in the growing environment. As such, since the plant itself determines the water needs for sustained growth, a reliable water irrigation reservoir and capillary n:\gis-proj\2002\ ccsd master plan\final recycled water mp\appendix a2.doc