Loading...
HomeMy WebLinkAbout; Recycled Water Master Plan 2012 Part 2; Recycled Water Master Plan 2012 Part 2; 2012-01-12 January 2012 4-25 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 4 In addition, the stormwater impounded in Lake Calavera is utilized in this alternative by providing a stormwater treatment facility that would treat this water during the peak summer months (July through September) to provide additional supply. Per the CMWD’s 2006 Lake Calavera Annual Management and Daily Operations Plan (CMWD, 2006), the reservoir has a 25-foot operational storage range between 189 ft-msl and 214 ft-msl. This operational storage range provides a total storage capacity of 480 MG. The report also states that the annual dry year runoff into the reservoir varies between 32 and 97 MG. Based on this information, the proposed stormwater treatment plant is sized to treat 90 MG in 90 days, which equates to 1 mgd. The location of this proposed facility is shown on Figure 4.4. Based on similar treatment of surface water sources, the proposed stormwater treatment plant (SWTP) is outlined based on a conventional treatment process involving a rapid mix chamber, coagulation in a flocculation basin, sedimentation, filtration, and chlorine addition. This process assumes that the water in Lake Calavera has characteristics typical of a surface water supply. During planning and design of a potential plant, the processes used could change depending on the measured water quality of Lake Calavera. To connect this new SWTP with CMWD’s recycled water distribution system, 4,000 feet of 8-inch diameter pipeline along between the Calavera Reservoir and “C” Tank needs to be constructed as shown on Figure 4.4. This pipeline along with a new booster pumping station would provide a direct connection with Zone 384 and pump into the C-tank feedline. Connection to Zone 580 is not an option due to the limited maximum month demand (<0.4 mgd) of this pressure zone. The Carlsbad WRF would be expanded by 5.0 mgd to provide the balance of the required supply. It is assumed that the proposed expansion of the Carlsbad WRF from 4.0 mgd to 9.0 mgd can be accommodated at the current site and that this expansion will be limited to the tertiary treatment processes and disinfection capacity. As the plant already has approximately 14.4 mgd of effluent pumping capacity, no additional pumping capacity is anticipated. However, if the pump station at Carlsbad WRF is used to meet PHD, additional pumping capacity will be needed. To determine the capital construction cost of this alternative, the following key components were included: • 1-mgd stormwater treatment plant (SWTP) with microfiltration and UV disinfection. • 1-mgd discharge pumping station at the new SWTP to serve Zone 384. • 4,000 feet of 8-inch diameter pipeline between the Calavera Reservoir and “C” Tank. • 5-mgd tertiary filter capacity expansion at Carlsbad WRF. • 5-mgd chlorine contact basin capacity expansion at Carlsbad WRF. • No expansion of effluent pumping capacity at Carlsbad WRF. 4-26 January 2012 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 4 • 1,500 feet of 8-inch diameter pipeline and 75 hp pump station sized for 0.75 mgd to convey flow from Gafner WRP to distribution system (future Expansion Segment 8 in El Camino Real). The estimated capital cost of this alternative is $18.9 million. A detailed breakdown of this estimate is included in Appendix B. Assuming an annual demand of 4,098 afy made possible by this expansion, the unit supply cost of this alternative is estimated at $335/af. 4.4.6 Alternative 6 - Utilize Shadowridge WRP This alternative also expands CMWD’s current supply mix by securing water from a new supply source, while continuing to use recycled water from the Carlsbad WRF, Meadowlark WRF, and the Gafner WRP. Meadowlark WRF remains at current capacity in this alternative providing 3.0 mgd. Gafner WRP is connected to the distribution system, allowing full utilization of the 0.75 mgd allocation. Seasonal storage is used for 0.2 mgd of MMD supply. In addition, this alternative would utilize recycled water from a reactivated Shadowridge Water Reclamation Plant (SRWP), the location of which is shown on Figure 4.4. The VID is currently evaluating the necessary improvements required for reactivating the plant and has discussed the potential alternatives with CMWD. The two potential alternatives evaluated by VID’s study that would provide recycled water to CMWD’s system are shown in Table 4.8 (a third alternative supplied recycled water only to VID’s service area). Table 4.8 Alternatives for Expansion of Shadowridge WRP Recycled Water Master Plan Carlsbad Municipal Water District Shadowridge WRP Alternative(1) Plant Capacity (mgd) Supply to CMWD(2) (mgd) Unit Cost(3) w/ O&M ($/acre-foot) Unit Cost w/o O&M ($/acre-foot) Alternative 2 1.0 0.7 $1,520 $714 Alternative 3 2.0 1.7 $1,070 $567 Notes: (1) Alternative 1 does not consider service to CMWD’s recycled water system. (2) These flows are average annual supply. See discussion below for further information. (3) Source: Draft Summary of Shadowridge WRF Upgrade and Renovation Alternatives. VID’s reactivation study assumed Carlsbad would purchase all excess water. See discussion below for further information. As seen in Table 4.8, the anticipated average annual supply to CMWD would be 0.7 mgd and 1.7 mgd under Alternatives 2 and 3, respectively. It is important to note that under each of the alternatives, the calculations of unit cost assume that CMWD will purchase all recycled water not used by the Shadowridge Golf Course. January 2012 4-27 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 4 As shown in Table 4.8, VID’s study also included operations and maintenance costs. Since the comparison presented in this section for each supply alternative presents capital costs, the operations and maintenance costs are deducted in Table 4.8 for relative comparison purposes. Operations and maintenance costs by supply source will be included in Section 4.4.8. Since the demand of the Shadowridge Golf Course will peak in the summer and be very low in the winter months, the availability of this supply will be opposite from CMWD’s seasonal supply requirements, as shown in Table 4.9. Table 4.9 Seasonal Supply Related to Shadowridge WRP Recycled Water Master Plan Carlsbad Municipal Water District Average Day (mgd) Maximum Month(1) (mgd) Minimum Month(2) (mgd) CMWD’s Existing Demand 3.6 6.1 0.7 Build Out Demand (with Neighboring Agencies) 8.1 13.5 1.6 Supply with Alternative 2 0.7 0.3 1.0 Supply with Alternative 3 1.7 1.3 2.0 Notes: (1) Discussions with CMWD staff indicated that demands of the Shadowridge Golf Course during Maximum Month demand conditions are anticipated to be 0.7 mgd. (2) Source: Draft Summary of Shadowridge WRF Upgrade and Renovation Alternatives. VID’s reactivation study assumed Carlsbad would purchase all excess water. See discussion below for further information. Discussions with CMWD staff indicated that demands of the Shadowridge Golf Course during Minimum Month demand conditions are anticipated to be zero. As shown in Table 4.9, even under the build-out conditions, the minimum month demand of 1.6 mgd would still be less than the 2.0 mgd supply during minimum months from Shadowridge WRP (Alternative 3). As the unit costs shown in Table 4.8 necessitate that CMWD purchase all excess water generated by Shadowridge WRP, CMWD would not be able to take supply from Meadowlark WRF while paying for its full allotment of 2 mgd. Based on this, Shadowridge WRP Alternative 3 is not financially feasible and Alternative 2 was used for this study. It should be noted that CMWD’s build-out minimum month demand would still under utilize supply from Meadowlark WRF under this alternative. Carlsbad WRF would be expanded by 5.75 mgd to provide the balance of the required supply. It is assumed that the proposed expansion of the Carlsbad WRF from 4 mgd to 9.75 mgd can be accommodated at the current site and that this expansion will be limited to the tertiary treatment processes, disinfection, and effluent pumping capacity. As the plant already has approximately 14.4 mgd of effluent pumping capacity, additional pumping capacity is not anticipated. However, if the pump station at Carlsbad WRF is used to meet PHD, additional pumping capacity will be needed. 4-28 January 2012 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 4 The unit costs shown in Table 4.8 do not include conveyance from Shadowridge WRP to CMWD’s distribution system. As a part of discussions with VID, several alternatives for delivery of recycled water from the Shadowridge WRP to CMWD’s system were suggested. The two most feasible of these delivery methods were: • Conveyance by gravity through Shadowridge WRP’s existing failsafe pipeline to Carlsbad WRF, where it would need to be pumped back up to Zone 550. • Construction of a pump station at Shadowridge WRP to supply the recycled water to Zone 660. The capacity to transfer the additional supply from Zone 660 to Zone 550 would need to be developed within the infrastructure of CMWD’s distribution system. Table 4.10 Preliminary Costs for Delivery from Shadowridge WRP Recycled Water Master Plan Carlsbad Municipal Water District Cost Component Alternative 1: Gravity Flow to El Camino Real and Palomar Airport Rd. Alternative 2: Pressurized Flow to Zone 660 at Melrose Dr. and Faraday St. Pump Station Size (hp) 70 60 Cost $660,000 $550,000 Transmission Main $190,000 $750,000 PRS - $50,000 Total $850,000 $1,350,000 Based on the preliminary cost estimate shown in Table 4.10, it is estimated that conveyance through the gravity pipeline would be the most cost-effective solution and will be used for comparison costs for this supply alternative. Alternative 2 is the more costly option due to the additional transmission main improvements required to convey flow through Zone 660 and a new pump station that would be needed at Shadowridge WRP. To determine the capital construction cost of this alternative, the estimated capital costs from VID’s reactivation study were combined with the conveyance and expansion costs for Carlsbad WRF. The following key components were included: • 1-mgd reactivation of Shadowridge WRP (cost from VID study). • 1-mgd pump station to Zone 550 at the delivery point from Shadowridge WRP (near El Camino Real and Palomar Airport Road). • 750 feet of 12-inch diameter pipeline between the failsafe pipeline, pump station, and distribution system. • 5.75-mgd tertiary filter capacity expansion at Carlsbad WRF. • 5.75-mgd chlorine contact basin capacity expansion at Carlsbad WRF. • No additional effluent pumping capacity at Carlsbad WRF. January 2012 4-29 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 4 • 1,500 feet of 8-inch diameter pipeline and 75 hp pump station sized for 0.75 mgd to convey flow from Gafner WRP to distribution system (future Expansion Segment 8 in El Camino Real). The estimated capital cost of this alternative is $22.8 million. A detailed breakdown of this estimate is included in Appendix B. Assuming an annual demand of 4,098 afy made possible by this expansion, the unit supply cost of this alternative is estimated at $404/af. 4.4.7 Supply Evaluation Summary A summary of the supply alternatives evaluation is shown in Table 4.11 and graphically presented on Figure 4.7. Table 4.11 Supply Alternatives Cost Comparison Recycled Water Master Plan Carlsbad Municipal Water District Supply Source Facility Treatment Flow (mgd) Alternative 1 Maximize CWRF Alternative 2 Maximize MWRF Alternative 3 Maximize GWRP Alternative 4 Abandon GWRP Alternative 5 Maximize CWRF and Lake Calavera Alternative 6 Utilize Shadowridge WRP Carlsbad WRF 10.25 9.75 7.00 11.00 9.00 9.75 Meadowlark WRF 3.00 3.50 3.00 3.00 3.00 3.00 Gafner WRP(4) 0.75 0.75 4.00 - 0.75 0.75 Calavera Reservoir SWTF - - - - 1.00 - Seasonal Storage - - - - 0.25 0.20 Shadowridge WRP - - - - - 0.30 Total Supply (mgd) 14.00 14.00 14.00 14.00 14.00(5) 14.00 Capital Cost ($ million) $10.8 $16.9 $73.6 $10.2 $18.9 $22.8 Unit Cost(1) ($/acre-foot) $191 $300 $1,305 $181 $335 $404 Notes: WRF = Water Reclamation Facility; WRP = Water Reclamation Plant; SWTF = Stormwater Treatment Facility (1) Unit Cost based on average supply capacity of 9,106 afy (an increase of 4,098 afy from the current supply of 5,008 afy). 4-30 January 2012 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 4 $191 $300 $1,305 $181 $335 $404 $0 $200 $400 $600 $800 $1,000 $1,200 $1,400 $1,600 0 2 4 6 8 10 12 14 16 Alt. 1 Alt. 2 Alt. 3 Alt. 4 Alt. 5 Alt. 6 Unit Supply Cost ($/af)Supply Capacity (mgd)CWRF GWRP MWRF SWTP Seasonal Storage SWRP Unit Cost ($/af) Figure 4.7 Supply Alternatives Comparison As shown on Figure 4.7, the majority of the recycled water supply capacity is produced at the Carlsbad WRF in all alternatives, ranging from 7 to 11 mgd of the total 14-mgd supply capacity. This figure clearly shows that the variations between alternatives are determined by the supply mix of the remaining 3 to 7 mgd of the total 14-mgd supply capacity. In addition to the supply mix of each alternative, Figure 4.7 also shows the estimated unit capital supply cost in dollars per acre-foot. These unit supply cost are based on the project components discussed in Sections 4.4.1 through 4.4.6, which are presented in more detail in Appendix B. The total capital costs of each alternative are depreciated over a 30-year period and amortized with a 6 percent interest rate. As shown in Figure 4.7, the estimated unit supply costs range from $181/af to $1,305/af. It should be noted that this cost does not include the cost of secondary treatment at EWPCF, land acquisition costs, existing costs of recycled water, nor operations and maintenance cost of treatment and distribution system facilities. January 2012 4-31 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 4 Based on the capital unit supply cost comparison, it can be concluded that Alternative 4 is the most cost-effective alternative and that Alternative 1 is a close second-best alternative. However, it should be noted that this evaluation does not include O&M cost, which is discussed in the next section. A final recommendation is therefore made at the end of this chapter. Some additional benefits of Alternatives 1 and 4 are: • Carlsbad WRF was originally designed to be expanded to 16 mgd and the facility layout and distribution system are designed with this ultimate capacity in mind. Carlsbad WRF has therefore sufficient land available for expansion. • Carlsbad WRF has the necessary treatment processes and configuration to remove TDS and manganese to acceptable levels through the microfiltration and reverse osmosis process that treats 20 percent of the total flow. Note that it is assumed that expansion of the microfiltration and reverse osmosis process is not necessary and the long-term efficiency of use of the microfiltration and reverse osmosis process to treat manganese should be evaluated during design of the expansion. • Carlsbad WRF is owned and operated by CMWD and therefore does not require any inter-agency agreements. CMWD will have more control over the expansion, operation, and maintenance of this facility compared to the Gafner WRP or Meadowlark WRF, which are owned and operated by other agencies. Alternative 2 maximizes the use of the Meadowlark WRF at 3.5 mgd. This alternative would require CMWD to obtain all the supply rights from this plant from OMWD. This would only be feasible if OMWD obtained more recycled water from CMWD’s distribution system, which would require an expansion of the Carlsbad WRF similar in size to Alternative 1. OMWD could purchase recycled water from CMWD through a new connection pipeline along El Camino Real that would connect CMWD’s Zone 384 with OMWD’s recycled water system near La Costa Golf Course as OMWD already has infrastructure in place south of this golf course. Moreover, Alternative 2 would also require OMWD to construct one or more booster pump stations to deliver water from the new connection to their higher pressure zones, which are currently fed by gravity from Mahr Reservoir and the Meadowlark WRF. As this supply strategy is not attractive for operational, design, and reliability considerations, it is not likely that OMWD would exchange supply from Meadowlark WRF with supply from Carlsbad WRF. Due to the uncertainty of OMWD’s expansion plans and schedule, it is recommended that CMWD not plan for additional supplies from the Meadowlark WRF. 4-32 January 2012 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 4 Alternative 3 is not recommended as it is the most expensive alternative in $/af. The relatively high cost is attributed to the required MF/RO treatment required for the plant expansion at the Gafner WRP, due to Gafner WRP’s limited onsite space. Another factor impacting the cost of this alternative is the water quality constraints as Gafner WRP would need to provide water meeting the TDS requirements of the basin plan. Alternative 5 is not recommended as the SWTP and pipeline make this alternative relatively costly as it would only operate potentially 7 months per year during a wet year. In addition, treated stormwater may pose water quality concerns and variable lake levels may cause environmental concerns and could require mitigation measures. With sufficient secondary effluent and potential treatment capacity available at the Carlsbad WRF, the use of runoff water in Lake Calavera as a recycled water supply source is not cost-effective at this time. Alternative 6 is not recommended since it is more costly than Alternatives 1, 2, 4, and 5, but does not provide the benefit of maintaining facilities under CMWD’s own control. CMWD is able to take advantage of economies of scale in expanding the Carlsbad WRF more efficiently than reactivating the Shadowridge WRP, while not being concerned with interagency agreements and coordination to ensure that the Shadowridge WRP operates at capacity to meet a contracted 1-mgd delivery of recycled water. This alternative would also underutilize the Meadowlark WRF in the near-term, making the overall supply cost even higher. 4.4.8 Unit Cost Comparison by Supply Source In addition to the comparison of supply alternatives, the unit supply cost for each supply source was calculated to take into account the purchase agreements for recycled water from neighboring agencies as well as the operations and maintenance costs paid by CMWD. The unit costs for each supply source are shown in Table 4.12. Note that the flows shown are based on full utilization of each source, and thus are not necessarily comparable to the unit costs shown in the previous section. As shown in Table 4.12, Carlsbad WRF is CMWD’s lowest cost supply source when considered on a unit cost basis. Meadowlark WRF is CMWD’s second lowest cost supply source. Note that Gafner WRP and Meadowlark WRF both have minimum purchase agreements, below which unit costs of supply will effectively increase. It is assumed that Shadowridge WRP would have a similar agreement. January 2012 4-33 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 4 Table 4.12 Supply Source Unit Cost Comparison Recycled Water Master Plan Carlsbad Municipal Water District Supply Source Facility Unit Cost ($/af) Based On Capital O&M Total Carlsbad WRF(1) 10.25 mgd $259 $249(2) $508 Gafner WRP(3) 0.6 mgd $988 Meadowlark WRF(4) 2.67 mgd $80 $481 $561 Shadowridge WRP(5) 0.7 mgd $715 $805 $1,520 Calavera SWTF(6) 1 mgd $610 $448 $1,058 Notes: (1) Based on cost estimate for expanding Carlsbad WRF from 4 mgd to 10.25 mgd (Alternative 1) and existing capital recovery; incorporates effluent pumping cost to Zone 384. The unit cost of 259 $/af includes 68 $/af for the existing capital recovery associated with 4 mgd of capacity and 191 $/af for future capital recovery associated with the 6.25 mgd expansion. The O&M unit cost of $249 includes $78 associated with fixed costs and $171 associated with non-fixed costs. Note that this supply comparison assumes 5,725 afy utilization of the treatment plant capacity. Actual utilization may be substantially less due to peaking and the timeline of connecting customers. (2) Derived from Encina JPA FY08/09 costs listed in Encina JPA FY10/11 budget and supply volume from CMWD sales report to MWD for FY08/09. It was assumed that personnel and internal service fund costs would be similar to current costs. Non-personnel expenses, such as energy, chemicals, and repairs were assumed to scale based on utilization of Carlsbad WRF. (3) Based on current 2010 rate set at 99% of CMWD potable water rate and minimum purchase of 395 afy (0.35 mgd) of recycled water. Based on wholesale rate; no consideration of capital and O&M costs are included. Note that unit cost would also be applicable to supply of 0.75 mgd if capital costs for connection are excluded. (4) Based on capital recovery and O&M percentages listed in August 20, 2003 agreement with VWD and VWD operating budget for FY10/11. Assumed purchase of 2,989 afy. (5) Costs based on preliminary cost estimate of PBS&J study on reactivation of Shadowridge WRP. Assumed minimum purchase of 728 afy. (6) O&M cost are based on typical water treatment O&M costs from AWWA/WEF QualServe performance measurement program ($1,373 per MG processed). Calavera supply is 276 afy or 90 MG. 4.4.9 Potable Water Supplement Alternative CMWD’s existing facilities have sufficient capacity to accommodate existing and future customers through build out conditions for a portion of the year. However, the supply capacity is insufficient to meet the peak demands during the summer. The supply Alternatives 1 through 6 presented previously all provided combinations of treatment plant expansions to meet the build out recycled water demand with tertiary treated water. However, another alternative is to not build any new facilities and use potable water to supplement the recycled water supply during peak months. This option is referred to as the Potable Water Supplement Alternative and is compared with Alternative 4 to determine if it is cost-effective for CMWD should expand its treatment facilities. This comparison is based on the incremental treatment capacity needed to serve a build out demand of 9,106 afy. As the existing treatment facilities can serve about 5,008 afy and meet the seasonal demand needs, the incremental treatment capacity or potable water supplement capacity is based on an annual demand of 4,098 afy. 4-34 January 2012 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 4 To evaluate the cost effectiveness of using potable supplement water for seasonal peaking, the annual amount of supply in excess of the existing supply capacity was calculated based on a build-out demand of 9,106 afy. Based on the historical seasonal demand variation shown in purple on Figure 4.8, the required amount of potable supplement water was estimated at 2,271 afy. As it is anticipated that the build out demand of 9,106 afy will be reached around year 2030, the need and cost of potable supplement water will increase over time. To estimate the cost of this alternative, the potable water rate projected by SDCWA for year 2018 was used. This year represents the approximate time that about half of the remaining customers are connected, a few years before completion of Phase III. This is also SDCWA’s furthest year out for which a rate projection is available. SDCWA estimates that their wholesale rate will reach $1,757 per afy by 2018. Based on this wholesale rate and an annual potable water supplement demand of 2,271 afy, the annual cost of this alternative is estimated at nearly $4 million. This equates to a unit supply cost of $974/af using an annual demand of 4,098 afy. 2.0 2.0 2.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 2.0 0.9 0.8 1.2 3.9 4.0 4.0 4.0 4.0 4.0 4.0 4.0 2.4 0.8 0.8 0.8 0.8 0.8 3.4 5.1 5.7 4.2 3.9 0 200 400 600 800 1,000 1,200 0 2 4 6 8 10 12 14 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Monthly Demand (af)Average Daily Demand per Month (mgd)Meadowlark WRF Carlsbad WRF Gafner WRP Potable Supplement CMWD Build-out Demand (afy) Figure 4.8 Required Potable Supplement as Seasonal Supply January 2012 4-35 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 4 Table 4.13 presents a comparison of using potable supplement water with the capital and O&M cost associated with serving the incremental demand of 4,098 afy through an expansion of Carlsbad WRF as recommended in Alternative 4. The cost of Alternative 4 includes $181/af for capital expansion as shown in Table 4.11. In addition, the demand weighted O&M cost for operating the treatment plant expansion is about $377/af. The combined cost of Alternative 4 is therefore estimated at $568/af. Table 4.13 Comparison of Potable Water Supplement with Alternative 1 Recycled Water Master Plan Carlsbad Municipal Water District Cost Component Potable Water Supplement Alternative(1) Alternative 4 6-mgd Carlsbad WRF Expansion(2) Capital Cost ($) - $10,800,000 Annual Cost ($/year) $3,990,147 $785,000 Unit Cost ($/af) $974(3) $568(4) Notes: (1) Based on annual demand of 9,106 afy for build out. Assumed to have negligible capital costs (potentially, additional potable supplement water through an air gap). (2) Based on annual demand of 9,106 afy for build-out of CMWD service area and neighboring agencies. (3) Unit cost only reflects the cost of 4,098 afy of wholesale treated water and does not include the unit cost for the other supply sources needed to meet the annual demand of 9,106 afy. (4) Based on $191 per af for capital recovery of the Carlsbad WRF expansion; $78 per af for fixed O&M costs at Carlsbad WRF; $171 per af for non-fixed costs at Carlsbad WRF; $377 per af for O&M and $481 per af for Meadowlark WRF As shown in Table 4.13, Alternative 4 is much more cost-effective than purchasing potable supplement water. This comparison does not include the cost of supplying up to 5,008 afy with the existing facilities, as those costs will be the same for both alternatives. This analysis also does not consider the loss of MWDSC’s LRP reimbursement, energy cost due to elevation difference between the potable water connection and Carlsbad WRF. It should be noted that the use of potable supplement water may be practical and required on an incidental basis, but that this is not a valid long-term supply strategy, especially when potable water rates continue to increase over time. 4.4.10 Recommended Supply Alternative The recommended alternative for expanding recycled water supply is Alternative 4, which calls for a 7-mgd treatment plant expansion at the Carlsbad WRF. Alternatively, CMWD may want to consider Alternative 1, which calls for a 6.25-mgd treatment plant expansion at Carlsbad WRF. The expansion of Carlsbad WRF will need to be implemented based on the phasing of demands and expansion segments discussed in Chapter 9. Phasing of each increment of expansion of the treatment plant and the associated supply strategy will be discussed in more detail in Chapter 9. 4-36 January 2012 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 4 This page intentionally left blank. January 2012 5-1 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 5 Chapter 5 RECYCLED WATER REGULATIONS The production, discharge, distribution, and use of recycled water are subject to federal, state, and local regulations. The primary objective of these regulations is to protect public health. This chapter starts with a discussion of the roles and responsibilities of the agencies involved in the use of recycled water. Subsequently, the existing regulations on federal, state, regional, and local level are described. This chapter is concluded with a discussion on future regulations and the impact to the Carlsbad Municipal Water District (CMWD). 5.1 OVERVIEW OF REGULATING AGENCIES The 1996 Memorandum of Agreement (MOA) between the California Department of Public Health (CDPH), the State Water Resources Control Board (SWRCB), and the Regional Water Quality Control Boards (RWQCBs) allocate the primary areas of responsibility and authority between these agencies on the use of recycled water. The CDPH is the primary state agency responsible for public health, whereas the SWRCB and the RWQCBs are the primary state agencies charged with protection, coordination, and control of surface and groundwater quality. These agencies work together to develop plant discharge or master reclamation permits for recycled water projects. Generally, the CDPH interprets the laws dictated by the California Code of Regulations (CCR) applicable to reclamation and makes recommendations on individual projects to the RWQCB. The RWQCB issues the final permit for water reclamation projects. In addition, in the County of San Diego, the CDPH has delegated the review of proposed recycled water use areas, use site distribution plans, complete cross connection control shutdown testing, and use site inspections to the County’s Department of Environmental Health (DEH). The roles of the agencies involved in the management of recycled water are summarized in Table 5.1. 5.2 FEDERAL REGULATIONS While wastewater discharges are governed by both federal and state requirements, currently there are no federal regulations that directly govern water recycling practices in the United States. Federal regulations relevant to the discharge of recycled water, 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 (Public Law 92-500). 5-2 January 2012 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 5 Table 5.1 Roles of Agencies Involved in Recycled Water Use Recycled Water Master Plan Update Carlsbad Municipal Water District Responsibility CDPH RWQCB City of Carlsbad RW Customer DEH Treatment Facility Review treatment plant design criteria x X Title 22 Engineering Report x X Treatment Plan Inspections x X Discharge Permits x X Enforcement actions for non-compliance x X Distribution System Review for standards compliance x X Recycled water permits X Annual Title 17 Inspections X Backflow prevention device testing X x Review cross-connection programs x Customer Site Areas Develop standards for use areas X x Review/approve supplier rules and regulations x X On-site inspection x x X X Cross-connection inspection X X X Cross-connection testing X X X Monitoring on-site use X X x Enforcement actions for non-compliance x X x Notes: Source: California-Nevada Section American Water Works Association (AWWA, 1997) X = Entity with primary responsibility x = Entity with secondary responsibility Federal requirements relevant to the use of recycled water for groundwater recharge are contained in the 1986 amendments of the Safe Drinking Water Act of 1974 (Public Law 93-523). The Safe Drinking Water Act focuses on the regulation of drinking water and control of public health risks by establishing and enforcing maximum contaminant levels (MCLs) for various compounds in drinking water. January 2012 5-3 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 5 5.3 STATE REGULATIONS 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 13999.16 (Water Code); • California Administrative Code, Title 22 – Social Security, Division 4 – Environmental Health. Chapter 3 – Water Recycling Criteria, Sections 60301 through 60475; • California Administrative Code, Title 17 – Public Health, Division 1 – State Department of Health Services, Chapter 5 – Environmental Sanitation, Subchapter 1, Group 4 – Drinking Water Supplies, Sections 7583 through 7630. In addition, guidelines for the production, distribution, and use of recycled water have been prepared or endorsed by state agencies administering recycled water regulations. A summary of existing and future CDPH statutes and regulations, along with the pertinent available guidance documents, is listed in Table 5.2. Table 5.2 Summary of California Recycled Water Regulations Recycled Water Master Plan Carlsbad Municipal Water District Regulations Title 22, Division 4, Environmental Health, Chapter 3 Title 17, Division 1, California Department of Public Health, Chapter 5 Statewide Recycled Water Policy Statutes Health and Safety Code, Division 6, Part 1, Sanitary Districts Act of 1923, Chapter 4 Water Code, Division 7, Water Quality, Chapters 7 & 7.5 Draft Legislation Groundwater Recharge Reuse (August 2009) Guidance Documents Preparation of an Engineering Report for the Production, Distribution and Use of Recycled Water Sources: (1) http://www.cdph.ca.gov/healthinfo/environhealth/water/Pages/Waterrecycling.aspx (CDPH, 2009a) (2) http://www.cdph.ca.gov/certlic/drinkingwater/Pages/Lawbook.aspx (CDPH, 2009b) 5.3.1 State Water Code The Porter-Cologne Water Quality Control Act (CWC – Division 7), which was promulgated in 1969, established the SWRCB as the state agency with primary responsibility for the coordination and control of water quality, water pollution, and water rights. Nine RWQCBs were established to represent the SWRCB regionally and carry out the enforcement of water quality and pollution control measures. In addition, each RWQCB is required to formulate and adopt water quality control plans, establish requirements for waste discharge 5-4 January 2012 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 5 to waters of the state, and has the authority to carry out provisions of the federal Clean Water Act. The San Diego RWQCB has jurisdiction over the City of Carlsbad. 5.3.2 Code of Regulations – Title 22 In accordance with the requirements of Division 7 – Chapter 7 of the Water Code, CDPH prepared Title 22 in 1975. The current requirements of Title 22, as revised in 1978, 1990, and 2001, regulate production and use of recycled water in California. Title 22 establishes the quality and/or treatment processes required for an effluent to be used for a specific non- potable application, such as irrigation. The following categories of recycled water are identified: • Undisinfected secondary recycled water • Disinfected secondary-23 recycled water (23 refers to the coliform count requirement of 23 MPN/100 mL) • Disinfected secondary-2.2 recycled water (2.2 refers to the coliform count requirement of 2.2 MPN/100 mL) • Disinfected tertiary recycled water • Disinfected tertiary recycled water with conventional treatment • Disinfected tertiary recycled water without conventional treatment The recycled water uses allowed by Title 22 are dependent on the effluent quality of the supply source. As the effluent of the Carlsbad Water Reclamation Facility (WRF), Meadowlark Water WRF, and the Gafner Water Reclamation Plant (WRP) are all classified as ‘Disinfected Tertiary Recycled Water’ per Title 22, the effluent water quality of each meets or exceeds the criteria listed in Table 5.3. Table 5.3 Effluent Quality Standards for Unrestricted Use per Title 22 Recycled Water Master Plan Update Carlsbad Municipal Water District Treatment Oxidized, Coagulated (or Filtered), and Disinfected BOD5 Not Specified TSS Not Specified Turbidity 2 NTU (Daily Average) 5 NTU (Maximum during 5% of the time in a 24-hour period) 10 NTU (Maximum at any time) Total Coliform MPN(1) 2.2/100 mL (Medium) 23/100 mL (Maximum in 30 days) Note: (1) No sample shall exceed an MPN (most probable number) of 240 total coliform bacteria per 100 milliliters during any 30-day period. January 2012 5-5 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 5 The effluent from the Carlsbad WRF, Meadowlark WRF, and Gafner WRP meet or exceed these requirements. As such, the recycled water may be used for all applications listed in Table 5.4. Table 5.4 Approved Use Applications for Disinfected Tertiary Recycled Water Recycled Water Master Plan Update Carlsbad Municipal Water District Irrigation Uses Food crops where recycled water contacts the edible portion of the crop, including all crop roots Parks and playgrounds School yards Residential landscaping Unrestricted-access golf courses Food Crops, surface-irrigated, above-ground edible portion, and non contacted by recycled water Cemeteries Restricted-access golf courses Ornamental nursery stock and sod farms with unrestricted public access Freeway landscaping Pasture for milk producing animals for human consumption Nonedible vegetation with access control to prevent use as a park, playground or school yard Vineyards with no contact between edible portion and recycled water Non food-bearing trees, including Christmas trees not irrigated less than 14 days before harvest Fodder and fiber crops and pasture for animals not producing milk for human consumption Seed crops not eaten by humans Food crops undergoing commercial pathogen destroying processing before consumption by humans Any other irrigation uses not prohibited by other provisions of the California Code Requirements Supply for Impoundment Non-restricted recreational impoundments, with supplemental monitoring for pathogenic organisms Restricted recreational impoundments and publicly accessible fish hatcheries Landscape impoundments without decorative fountains Supply for Cooling and Air Conditioning Industrial or commercial cooling or air-conditioning involving cooling tower, evaporative condenser, or spraying that creates mist Industrial or commercial cooling or air-conditioning not involving cooling tower, evaporative condenser, or spraying that creates mist 5-6 January 2012 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 5 Table 5.4 Approved Use Applications for Disinfected Tertiary Recycled Water Recycled Water Master Plan Update Carlsbad Municipal Water District Other Allowed Uses Flushing toilets and urinals Priming drain traps Industrial process water that may contact workers Structural fire fighting Decorative fountains Commercial laundries Soil compaction Dust control on roads and streets Flushing sanitary sewers Consolidation of backfill material around potable water pipelines Backfill consolidation around nonpotable piping Artificial snow making for commercial outdoor use Commercial car washes, not heating the water, excluding the general public from washing processes Industrial process water that will not come into contact with workers Industrial boiler feed water Non-structural fire fighting Mixing concrete Cleaning roads, sidewalks, and outdoor work areas Other Uses Subject to RWQCB Approval Groundwater recharge (permits issued on a case-by-case basis by the RWQCBs) The current Title 22 requirements are also known as the “Purple Book”. The most recent compilation of recycled water laws can be found online [http://www.cdph.ca.gov/certlic/drinkingwater/Pages/Lawbook.aspx]. Regardless of the approved regulatory uses of Title 22 water, CMWD is limited to those uses stated either in its individual permit, or in a general permit that covers multiple users in the area. Currently, under Section B of CMWD’s permit, requirements are only stipulated for landscape irrigation. Other additional uses of recycled water not identified in the permit would need approval from the local RWQCB and CDPH office. 5.3.3 Code of Regulations – Title 17 The focus of Title 17 is protection of (potable) drinking 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, specifies the minimum backflow protection required on the potable water system for situations in which January 2012 5-7 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 5 there is potential for contamination to the potable water supply. 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 unless the recycled water supplier obtains approval from the local public water supplier to utilize an alternative backflow prevention plan that includes an annual inspection and annual shutdown test of the recycled water and potable water systems”. 5.3.4 Draft Groundwater Recharge Legislation A draft regulation issued on August 8, 2008 specifically addresses Groundwater Recharge Reuse. The regulations address requirements for the engineering report and monitoring and reporting projects that use recycled water for groundwater recharge. Specific requirements included in these draft regulation are as follows: • Groundwater recharge can only be undertaken with disinfected tertiary recycled water. • Recharged recycled water must be retained underground for a minimum of six (6) months prior to extraction for use as drinking water supply. • Monitoring of groundwater is mandated at a location where: – recycled water has been retained in the saturated zone for 1-3 months, but will take at least 3 months before reaching the nearest domestic water supply well – locations between the recharge area and the nearest down gradient domestic water supply well 5.3.5 Statewide Recycled Water Policy To reduce the uncertainty of the regulatory requirements for recycled water, the SWRCB adopted a statewide Recycled Water Policy in May 2009 (SWRCB, 2009). The impetus for the development of a statewide Recycled Water Policy stemmed from the current water crisis and a need to streamline and expedite the use of recycled water throughout the state in a manner consistent with existing state and federal laws. The purpose of the policy is to provide direction to the RWQCBs and the public on the appropriate criteria for issuing permits for recycled water projects. The policy follows Title 22 requirements and intends to streamline recycled water use through the following measures: 5-8 January 2012 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 5 • Streamlining of Recycled Water Use Permits. The policy establishes consistent criteria that are intended to streamline the permitting process for the vast majority of recycled water applications. These criteria should expedite projects and allow the RWQCBs both the time and authority to focus resources on projects with site-specific conditions. Projects that are eligible for enrollment under a general order shall be enrolled within 60 days. Other applications not enrolled in a general order shall be considered for permit adoption within 120 days by the RWQCB if certain criteria are met. • Mandated Recycled Water Use. The SWRCB establishes a statewide mandate to increase the use of recycled water by 200,000 acre-feet per year (afy) by 2020 and by an additional 300,000 afy by 2030. Agencies not providing a downstream beneficial use for recycled effluent are required to make it available on reasonable terms. Existing legislation considers it a waste if recycled water is not utilized when available (Water Code Sections 13550 et seq.). As part of this new policy, the SWRCB would exercise its authority pursuant to Water Code Section 275 to enforce the aforementioned mandates. The mandates are contingent on the availability of sufficient capital funding for the construction of recycled water projects from private, local, state, and federal sources. • Salt Nutrient Management Plans. By 2014, all basins are required to develop salt and nutrient management plans (with a two-year extension available). Such plans will help areas meet water quality objectives on a basin wide basis instead of restricting individual recycled water projects. The Basin Plan developed by the Santa Ana Watershed Project Authority (SAWPA) and the Basin Plan being developed by the San Diego County Water Authority (SDCWA) have become examples for the entire state on how to prepare these plans. The salt and nutrient management plans work in conjunction with the Basin Plans, which cover salts as well as other constituents, to preserve the existing groundwater quality. • Anti-Degradation. Projects that use recycled water for groundwater recharge are approved depending on a basin’s capacity to assimilate the increased concentrations of chlorides and other compounds that may be present in recycled water. If necessary, projects would need to implement anti-degradation measures in order to gain approval. Recycled water use projects that meet the criteria for streamlined permitting in a basin with a salt and nutrient management plan do not need to perform an anti-degradation investigation. These criteria are defined in detail in the Recycled Water Policy (SWRCB, 2009). • Funding. The SWRCB will request priority funding for storm water and recycled water projects that augment the local water supplies from Department of Water Resources (DWR). January 2012 5-9 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 5 Additional measures are included in the policy to ensure that recycled water use does not adversely affect groundwater basin quality. Such measures include: • Monitoring of Groundwater Basins. The salt and nutrient management plans require the use of monitoring wells to record water quality data, which needs to be submitted to the Regional Board every three years. • Constituents of Emerging Concern. Groundwater recharge projects are required to test and monitor constituents of emerging concern (CECs). A Blue Ribbon Panel has conducted a study on CECs and has prepared a Final Report, which is anticipated to be adopted in 2011. This report has prioritized four compounds for groundwater recharge projects based on their toxicological relevance. These four compounds are caffeine, a female hormone (17beta‐estradiol), an antibacterial agent (triclosan), and a disinfection by-product (N-nitrosodimethylamine). These CECs need to be monitored to determine if the concentrations may be cause for any concern. Due to the limited data available on CECs, there are no Action Levels (AL) or MCL established at this time. • Control of Incidental Runoff. Landscaping projects using recycled water are required to control the incidental runoff of recycled water through measures that include, but are not limited to, the following practices: installation and use of proper sprinkler heads; an operations and management plan (can apply to multiple sites); and application of limited irrigation during precipitation events. If an agency producing recycled water is not using it for a beneficial use as defined in the policy, that agency needs to provide that water to a purveyor on reasonable terms. As CMWD is currently planning to utilize the maximum amount of available recycled water possible, the policy does not have a significant impact on CMWD. CMWD could use the general use permit to streamline the permitting process for future irrigation customers. In addition, CMWD may want to monitor the impact of this policy to determine when any additional funding assistance will be available. 5.3.6 CDPH Guidelines To assist with the compliance with the requirements outlined in Title 22, the CDPH has prepared a number of guideline documents. Documents relevant to the production, distribution, and use of recycled water are: 5.3.6.1 Engineering Report According to CWC Section 13522.5, all water purveyors that use, or propose to use, recycled water must prepare an engineering report according to the guidelines described in the Guideline for the Preparation of an Engineering Report on the Production, Distribution, and Use of Recycled Water. This guideline is included in Appendix E. This report must be submitted to the appropriate RWQCB and CDPH. The report must describe the recycled water production process, including raw and treated water quality, treatment process, plant 5-10 January 2012 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 5 reliability features, supplemental water supply, monitoring program, and contingency plan to prevent distribution of inadequately treated water. The report must include maps of the distribution system and describe how the system will comply with CDPH and American Water Works Association (AWWA) guidelines and Title 17. The report must also include maps and descriptions of proposed use areas, types of uses proposed, people responsible for supervising the uses, design of the user systems, and the proposed user inspection and monitoring programs. 5.3.6.2 Cross-Connection Control The Manual of Cross-Connection Control/Procedures and Practices was prepared by CDPH in 1981 (and updated periodically) and 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 that pose a hazard to the potable water supply. It should be noted that the proposed revisions outlined for the Draft California 2010 Plumbing Code – Chapter 16 – Part II dated May 13, 2009 (see Appendix B), prohibit the use of backflow preventers between potable and recycled water systems and specifies that a recycled water system shall not have any connections to a potable water system (Section 1613.0 under A). 5.4 REGIONAL WATER QUALITY CONTROL BOARD While CDPH provides input to protect public health, the RWQCB created provisions in a permit for the protection of beneficial uses of water and the protection of water quality. These provisions are based on the Water Quality Control Plan the RWQCB has adopted, otherwise known as the Basin Plan. The Basin Plan is the RWQCB guide for the protection of the beneficial uses of water and the enhancement of water quality. This document provides water quality objectives for continued beneficial use of water resources. This study’s area of interest falls within Basin Plan hydrological unit 904.00, which is divided into five hydrologic subareas (HSAs). A map of the Basin location is shown in Figure 5.1. For this hydrologic region, the groundwater constituent limits from the Basin Plan are listed in Table 5.5. Groundwater constituent concentrations cannot exceed these limits more than 10 percent of the time during any one-year period. 21-Carlsbad510Fig5.1-8308A00.ai Carlsbad Watershed FIGURE 5.1 CARLSBAD MUNICIPAL WATER DISTRICT Loma Alta Buena Vista Creek Agua Hedionda Encinas San Marcos Escondido Creek 904.1 904.2 904.3 904.4 904.5 904.6 Hydrologic Unit 904.10 - 904.63 Hydrologic Areas: 5-12 January 2012 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 5 Table 5.5 Basin Plan Groundwater Quality Objectives Recycled Water Master Plan Update Carlsbad Municipal Water District Constituent (mg/L or as noted) El Salto HSA (904.21) Los Manos HSA(1,2,3) (904.31) Encinas HSA(1,4) (904.40) San Marcos HSA(5) (904.50) Batiquitos HSA(1,5,6) (904.51) Total Dissolved Solids 3,500 3,500 3,500 1,000 3,500 Chloride 800 800 800 400 800 Sulfate 500 500 500 500 500 Percent Sodium 60% 60% 60% 60% 60% Nitrate (as NO3) 45 45 45 10 45 Iron 0.3 0.3 0.3 0.3 0.3 Manganese 0.05 0.05 0.05 0.05 0.05 Methylene Blue Active Substances 0.5 0.5 0.5 0.5 0.5 Boron 2.0 2.0 2.0 0.75 2.0 Fluoride 1.0 1.0 1.0 1.0 1.0 Notes: Source: RWQCB, San Diego Region, Comprehensive Quality Control Plan for the San Diego Basin (1) The water quality objectives do not apply westerly of the easterly boundary of Interstate 5. (2) Notwithstanding the Basin Plan water quality objectives, the Regional Board will regulate discharges in HAS 904.31 in a manner that will protect the waters produced by existing operating wells. (3) The water quality objectives apply to the portion of HSA 4.31 bounded on the west by the easterly boundary of El Camino Real. (4) Detailed salt balance studies are recommended for determining limiting mineral concentration levels for discharge. Upon completion of the salt balance studies, significant water quality objective revision may be necessary. In the interim period of time, projects involving groundwater recharge with water quality inferior to the listed values may be permitted following individual review and approval by the Regional Board if such projects do not degrade existing groundwater quality to the aquifers affected by the recharge. (5) The water quality objectives do not apply to HSA 904.51 between Highway 78 and El Camino Real, and to all lands that drain to Moonlight Creek and Encinas Creek. The objectives for the remainder of the HSAs are shown. (6) The water quality objectives apply to the portion of HSA 904.51 bounded on the south by the north shore of Batiquitos Lagoon, on the west by the easterly boundary of Interstate 5 right-of-way, and on the east by the easterly boundary of El Camino Real. When issuing a recycled water reclamation or discharge permit, the RWQCB considers the water quality objectives in the Basin Plan. Typically, constituents cannot exceed the limit set forth by the Basin Plan for each hydrologic region. For Carlsbad, the water quality limits for the Carlsbad WRF, Meadowlark WRF, and Gafner WRP are defined in the respective wastewater discharge permits, which are included in Appendix E. The Carlsbad WRF master permit (Order No. 2001-352) includes the water quality limits that apply to the entire CMWD service area. These limits are summarized in Table 5.6. When comparing Table 5.5 and Table 5.6, it can be concluded that the Master Reclamation Permit requirements are more stringent for most constituents than the goals set forth in the Basin Plan. January 2012 5-13 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 5 Table 5.6 Master Reclamation Permit Requirements Recycled Water Master Plan Update Carlsbad Municipal Water District Constituent Daily Maximum (mg/L) 30-Day Average (mg/L) 12-Month Average (mg/L) Total Dissolved Solids (TDS) 1,200 - 1,100 Chloride 400 350 - Sulfate 400 - 350 Boron 0.75 0.75 0.75 Iron 0.4 0.3 0.3 Manganese 0.06 - 0.05 Fluoride - - 1.0 Methylene Blue Active Substances (Surfactant) - - 0.5 Note: Source: Master Reclamation Permit for Carlsbad Water Recycling Facility (RWQCB, 2001), included in Appendix E. The Master Reclamation Permit issued to CMWD also contains numerous requirements for the purveyance of recycled water. These include: • Requirements for the initiation of recycled water service to a new customer including: – Develop rules and regulations governing the design and construction of recycled water use facilities (this is already in place) – Develop a compliance inspection program (this is already in place) – Submit irrigation plans to the CDPH and/or DEH for new connections • Requirements subsequent to the initiation of recycled water service but prior to the delivery of recycled water including: – Submit a report to the CDPH and DEH certifying that the new user site conforms with documentation previously sent to the CDPH and DEH – Conduct a complete cross-connection shut down test for each new use site – Verify that reclamation treatment facilities meet RWQCB requirements • Ongoing requirements for all reuse sites after the start of service including: – Enforce recycled water rules and regulations – Conduct recycled water reuse site compliance inspections – Notify the DEH and CDPH of any recycled water backflow into the potable system – Maintain a current list of all on-site recycled water supervisors 5-14 January 2012 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 5 5.5 LOCAL REGULATIONS Local regulations discussed in this chapter include regulations from San Diego County and CMWD. 5.5.1 County of San Diego Regulations The County of San Diego also has specific regulations governing the inspection and implementation of recycled water connections, contained in the Recycled Water Plan Check and Inspection Manual (DEH 2001 Edition). In San Diego County, the plan check and inspection responsibilities are shared between CDPH and the County of San Diego DEH. CDPH is responsible for the plan review of treatment processes, treatment plants, main conveyance systems, and proposed new and unusual uses of recycled water. In conjunction with CMWD staff, the DEH is responsible for plan review and inspections of all recycled water use sites. Off-Site Requirements: • Minimum Separation/Proximity of Utilities: Vertical separation requirements must be met if the pipeline maintains a positive pressure during the day. • Horizontal Separation: A 10-foot horizontal separation must be maintained between a recycled water pipeline and a sewer main or water pipeline. Separations smaller than 10 feet need approval from CMWD and/or the CDPH depending on the separation distance. The state now only requires a 4-foot horizontal separation between a disinfected tertiary treated recycled water pipeline and a potable pipeline. • Vertical Separation: A potable water line must be installed at least 1 foot above a recycled water line, which must be installed at least 1 foot above a sanitary sewer. On-Site Requirements: • Separation: At the user site, the separation of utilities is similar to the off-site requirements, but individual purveyors may modify the required on-site distances. Areas of potable water irrigation and recycled water irrigation must be physically separated either by distance, concrete mow strips, or other approved methods, such as fences or walls. • Minimum Depth: The minimum pipeline depth is defined in the City’s landscape manual and is as follows: – Pressured pipeline less than 3 inches in diameter require 18-inch cover – Pressured pipeline between 3 and 5.5 inches in diameter require 24-inch cover – Pressured pipeline of 6 inches and greater in diameter require 36-inch cover – Non pressured pipelines require 12-inch cover January 2012 5-15 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 5 • System Identification. All appurtenances related to the system (sprinkler heads, valve boxes, tags, quick couplers, etc.) must be color coded purple. All valve boxes shall be tagged with recycled water tags. On retrofit jobs, underground piping does not need to be changed. • Sprinkler Location. Sprinklers located close to swimming pools, eating areas, and sand-filled play areas for children should be of the bubbler non-spray type or have adjustable nozzles. Alternatively, sprinklers can be located so that these areas are not oversprayed. 180-degree turf sprinkler heads adjacent to sidewalks are not acceptable since they overspray and cover 190 degrees. • Sprinkler Coverage. Sprinklers must only cover the designated area. Measures need to be taken to avoid misting and wind blown mist. • Drinking Fountains. Drinking fountains must be protected from recycled water runoff, spray, or mist. • Ponds. If a pond is receiving recycled water, potable water to the pond must be delivered through an air gap. Ponds can have fountains provided that the County’s design guidelines are followed. • Food Establishments. Recycled water should not be installed near drive-through windows or outdoor patio eating areas. • Hours of Irrigation: The County’s Manual describes standard plan notes requiring hours for irrigation to be between 10:00 p.m. and 6:00 a.m. However, if the recycled water meets tertiary treatment standards, the local water authority may modify the hours for irrigation under the qualification that irrigation during public use periods is supervised. Thus, CMWD could modify the hours of irrigation for customer sites where supervision during public hours is possible. • Cross-Connection Testing: The County’s manual also specifies testing procedures and frequency to ensure that there are no cross connections with the potable water system. 5.5.2 District Mandatory Use Ordinance CMWD currently has an ordinance mandating the use of recycled water in accordance with California Water Code, Sections 461, 13510, and 13550. This ordinance is included in Appendix E of this report and summarized below. The ordinance recognizes that recycled water can reduce dependence on imported water and that certain uses of potable water may pose a nuisance where recycled water is available. Accordingly, the ordinance declares that recycled water shall be used within the jurisdiction wherever it is economically justified, financially and technically feasible, and 5-16 January 2012 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 5 consistent with legal requirements for preservation of public health, safety and welfare, and the environment. CMWD is responsible for making the preliminary determination as to which existing potable water customers shall be converted to recycled water. Notice of this determination is sent to the customer, and upon receipt the customer has 90 days to submit an implementation plan to CMWD. The cost for the preparation of this plan should be paid by the customers with the exception of customers that decide to ask CMWD to prepare this plan and are willing to sign an acknowledgement to accept and install the proposed improvements in the plan prepared by CMWD. Once approved, the plan must be implemented within six months. The customers have 30 days to contest any preliminary determination after notice of receipt. As part of the application process for a new development project, CMWD staff review planning documents to determine if the proposed development requires recycled water, if the proposed development should include provisions for future recycled water use, or if the development is considered suitable for recycled water. Provisions for a current or future recycled water connection may be required as a condition of approval. In addition, applications for remodeling of a property may also be reviewed for recycled water use feasibility. If the property in question is considered suitable for existing or future recycled water use, the use of recycled water may be conditioned on the remodeling application. The ordinance also specifies CMWD policies for requested recycled water service, plan approval, field inspection, temporary use of potable water (until recycled water is available), and the recycled water rate. The ordinance is adequate for CMWD’s purposes as it defines CMWD’s authority in requiring recycled water use, clearly lists criteria for identifying potential users, and outlines the process for new customer connections. 5.5.3 District Regulations and Design Standards CMWD has also developed rules and regulations for the use of recycled water. These rules and regulations are in included in the following three chapters of CMWD’s General Design Standards, Volume 2 – Potable and Recycled Water Standards (CMWD, 2010): • Chapter 2 – Rules and Regulations for Use of Recycled Water: This chapter sets forth the general requirements and conditions as well as the administrative requirements pertaining to the use of recycled water in CMWD as required by the Master Reclamation Permit, the CDPH, and the DEH. • Chapter 3 – Design Guidelines and Procedures: This chapter provides the design procedures, planning and design criteria, as well as the specifications for the location, type, and size of water facilities. January 2012 5-17 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 5 • Chapter 5 – Requirements for Onsite Recycled Water Systems: This chapter defines the design requirements, construction specifications, and operational requirements for onsite (private) recycled water systems. 5.6 FUTURE REGULATORY DEVELOPMENTS Future regulatory considerations for the use of recycled water consist of the anticipated updates to the Draft Groundwater Recharge Reuse Regulations and the 2010 California Plumbing Code. In addition, there are developments on the regulation of endocrine disrupting compounds (EDCs) and other CECs. 5.6.1 Groundwater Recharge As described in Section 5.3.4, the CDPH issued Draft Groundwater Recharge Reuse Regulations in August 2008 that contain treatment requirements for projects with an indirect potable reuse or recharge component (CDPH 2008). These requirements have been implemented for past projects and require such constraints as a minimum underground detention time. The Title 22 Regulations currently call for RWQCBs to review groundwater recharge projects on a case-by-case basis with input from CDPH. These draft regulations will be finalized in the future. Further information regarding the development of these draft regulations can be found on the CDPH website (CDPH, 2009). 5.6.2 Updates to the 2010 California Plumbing Code The California Plumbing Code is being updated to relax the restrictive rules for installing dual plumbing for indoor recycled water use, as well as gray water. These changes pertain to Chapter 16 of Title 24, Part 5 of the California Code of Regulations. The code revisions for recycled water were approved by the Building Standards Commission and will be part of the 2010 Code. The new rules remove some of the restrictions on the installation of recycled water pipe in buildings. The major features of the new dual plumbing rules are: • Recycled water pipe can now run in the same wall/ceiling cavity as potable pipe. • The labeling requirements for purple pipe are relaxed. • The annual inspection is a visible inspection, followed by a cross-connection test if there is reason to believe there is a cross-connection, rather than an automatic cross- connection test each year. • The use of potable water for backup supply or makeup water is not allowed. Recycled water systems must be completely separated from potable water systems. 5-18 January 2012 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 5 5.6.3 Constituents of Emerging Concern Recent advances in technology have allowed the detection of constituents that were previously undetected in the environment. Many of these constituents are classified as CECs since they are suspected of possibly posing a public health or ecological risk. CECs are not currently regulated by the Environmental Protection Agency (EPA), but many of these constituents are candidates for future regulations. As more scientific information becomes available, the EPA may impose regulations on some of these constituents. CECs include personal care products and pharmaceutical products. Many of these CECs are also considered EDCs. The primary concern of CEC is indirect potable reuse. As CMWD does not practice indirect potable reuse, CECs should not be a significant concern for CMWD at this time. Nevertheless, CMWD should be aware of CECs since the public at large has expressed concern with the potential for coming in contact with CECs through contact with edible crops irrigated by recycled water. As stated in Section 5.3.5, a Blue Ribbon Panel has prioritized four compounds for groundwater recharge projects based on their toxicological relevance. These four compounds are caffeine, a female hormone (17beta-estradiol), an antibacterial agent (triclosan), and a disinfection by-product (N-nitrosodimethylamine). In addition, other CECs are identified as viable performance indicator compounds, which differ by the type of reuse practice. However, none of the chemicals for which measurement methods and exposure data are available exceeded the threshold for monitoring priority. For irrigation applications, the Panel therefore recommends monitoring emphasis be placed on use of indicator CECs that can demonstrate that the treatment processes employed are effective in removing CECs. 5.6.4 Endocrine Disrupting Compounds In recent years, there has been heightened scientific awareness and public debate over potential impacts that may result from exposure to EDCs. Humans, fish, and wildlife species could potentially be affected by sufficient environmental exposure to EDCs. This discussion is provided to briefly communicate what is currently known about EDCs and to describe their position within California’s recycled water regulations. EDCs can be either natural or anthropogenic contaminants, which are chemicals that have been introduced to the environment by the activity of man. Plants, such as soybeans and garlic, produce natural EDCs as a defense mechanism. However, most EDCs are man-made synthetic chemicals, which are unintentionally released into the environment. Certain drugs, such as birth control pills, intentionally alter the endocrine system. Categories and sources of substances that are potential EDCs are presented in Table 5.7. January 2012 5-19 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 5 Table 5.7 Potential Endocrine Disrupting Compounds Recycled Water Master Plan Update Carlsbad Municipal Water District Category Examples of Substances Examples of Uses Examples of Sources Polychlorinated Compounds Polychlorinated dioxins, Polychlorinated biphenyls Industrial production of by-products (mostly banned) Incineration, landfill Organochlorine Pesticides DDT, Dieldrin, Lindane Insecticides (many phased out) Agricultural runoff Other Pesticides (current use) Atrazine, Trifluralin, Permethrin Pesticides Agricultural runoff Organotins Tributyltin Antifoulants on ships Harbors Alkylphenolics Nonylphenol Surfactants (and their metabolites) Industrial and municipal effluents Phthalates Dibutyl phthalate, Butylbenzyl phthalate Plasticizers Industrial effluent Hormones 17-beta estradiol, Estrone Produced naturally by animals Municipal effluents Synthetic Steroids Ehynylestradiol Contraceptives Municipal effluents Phytoestrogens Isoflavones, Ligands, Coumestans Present in plant material Pulp mill effluents Source: Canadian Wildlife Service, Pacific Wildlife Research Center (CWS, YEAR). Regulations Pertaining to EDCs In 1996, new legislation required that the U.S. EPA “determine whether certain substances may have an effect in humans that is similar to an effect produced by a naturally occurring estrogen or other such endocrine effect.” In response, the EPA developed the Endocrine Disrupter Screening and Testing Advisory Committee. In June 2008, they issued a draft white paper on how criteria for the synthetic birth control estrogen ethinyl estradiol might be developed in the future. Although some chemicals have been conclusively determined to be EDCs, many chemicals are termed “suspect” because there is not enough data to make a decisive determination regarding their endocrine disrupting characteristics. Some known EDCs (e.g., PCBs, DDT, chlordane) are already regulated via surface water quality standards or drinking water standards based on their toxicological and carcinogenic effects. However, no water quality standards currently exist for natural and synthetic estrogens or related pharmaceutical chemicals. Based on the current state of knowledge regarding dose-response relationships of EDCs for various organisms at the low-levels in which they can occur in surface waters, it is likely to be a number of years, possibly many years, before any such standards are promulgated. 5-20 January 2012 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 5 The EPA and other stakeholders looked at 7,500 substances and in December 2009 the EPA released its third contaminant candidate list (CCL3). The CCL3 includes 116 substances (104 chemicals and 12 microbiological contaminants) which are not currently regulated in drinking water by the federal government but may be considered for future regulation under the Safe Drinking Water Act (SDWA). The final CCL3 includes, among others, pesticides, disinfection byproducts, chemicals used in commerce, waterborne pathogens, pharmaceuticals, and biological toxins. 5.7 RECOMMENDATIONS CMWD currently abides by the stipulations imposed by CDPH through the Master Reclamation Permit, and DEH through CMWD standards found in Volume II Potable and Recycled Water Standards. Nevertheless for one DEH requirement, a physical separation between areas of irrigation with recycled and potable water, CMWD could add a qualifying phrase to Item 5.1.3.E of Chapter 5 of the standards to ensure that this physical separation is applied to both large, constantly pressurized pipes and small, intermittently pressurized pipes. After the start of the sentence, “Potable and recycled lines,” CMWD could add the qualifier, “including irrigation laterals.” This could help avoid situations where the physical separation exists for offsite pipes, but not for onsite irrigation laterals. CMWD staff have mentioned that significant effort is expended complying with the increased oversight requirements of the County. While this regulatory oversight is outside the control of CMWD, decreasing the amount of regulatory oversight would increase CMWD staff’s productivity and efficiency. In addition, CMWD will want to monitor funding opportunities that may result from the new Recycled Water Policy. Such funding could become available as the State’s budget situation improves. January 2012 6-1 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 6 Chapter 6 HYDRAULIC MODEL This chapter presents an overview of the activities undertaken to develop and calibrate the hydraulic model for Carlsbad Municipal Water District’s (CMWD) recycled water distribution system. This chapter contains the following sections: • Hydraulic Modeling Overview – This section explains the purpose of hydraulic models and modeling software selection. • Existing System Model Creation – This section describes the model development and the data and processes used to create each hydraulic model. • Existing System Model Calibration – This section describes the processes used to gather field data and calibrate each model in order to establish a level of confidence in the model results. • Future System Model Creation – This section describes the additions made to the calibrated model to analyze future system expansion opportunities. Detailed information on the calibration of each of the models is included in Appendix F, Model Calibration Results. Additional information on the use of the models is included in Appendix G, Model Manual. 6.1 HYDRAULIC MODELING OVERVIEW Innovations in personal computing and the large selection of software have made network analysis modeling efficient and practical for virtually any water system. Hydraulic modeling is an important tool for analyzing a water system. Hydraulic models can simulate existing and future water systems, identify system deficiencies, analyze impacts from increased demands, and evaluate the effectiveness of proposed system improvements, including those within capital improvement plans. In addition, a hydraulic model provides both the engineer and water system operator with a better understanding of the water system dynamics. Hydraulic models are typically composed of three main parts: • The data file that stores the geographic location of facilities. The geographic data file provides water system facility locations and is typically represented as an AutoCAD or geographic information systems (GIS) file. Elements used in this file to model system facilities include pipes, junction nodes (connection points for pipes and location of demands), control valves, pumps, tanks, and reservoirs. • A database that defines the physical system. The database for CMWD’s model is linked to the geographic data file. The database includes water system facility information such as facility size and geometry, operational characteristics, and production/consumption data. 6-2 January 2012 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 6 • A computer program “calculator”. This calculator solves a series of hydraulic equations based on information in the database file to define and generate the performance of the water system in terms of pressure, flow and operation status. The key to maximizing benefits from the hydraulic model is correctly interpreting the results so the user understands how the water distribution system is affected by the various components of the model. This understanding enables the engineer to be proactive in developing solutions to existing and future water system goals and objectives. With this approach, the hydraulic model is not only used to identify the adequacy of system performance, but is also used to find solutions for operating the water system according to established performance criteria. Developing an accurate and reliable computer model begins with entering the best available information into the database and calibrating the model to match existing conditions in the field. Once the model has been calibrated, it becomes a valuable tool to evaluate operational problems and to plan distribution system improvement projects. 6.1.1 Hydraulic Model Selection Several software programs are widely used to model distribution systems. The variety of program capabilities and features makes the selection of a particular software program generally dependent upon three factors: user preference, the requirements of the particular water distribution system, and the cost associated with the software. CMWD has selected H2OMAP® Water, developed by MWH Soft, Inc., for the hydraulic modeling of its recycled water distribution system. 6.1.2 Previous Hydraulic Model CMWD’s initial hydraulic model of its recycled water distribution system was developed in 2000 as a part of the Encina Basin Recycled Water Distribution System Study (JPA, 2000) using H2ONET® Version 2.0. The hydraulic model provided to Carollo Engineers at the beginning of this project was developed by CMWD staff in H2OMAP® Water. 6.2 EXISTING SYSTEM MODEL CREATION CMWD provided GIS layers containing relevant information concerning its pipeline network. Since the level of detail and topology of CMWD’s GIS layers was judged to be more representative of the recycled water distribution system than the previous hydraulic model, CMWD’s GIS layers were imported into the hydraulic model rather than the pipelines from the previous hydraulic model. Facilities and controls were then adapted from the previous hydraulic model. In summary, the model creation process involved the following steps: January 2012 6-3 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 6 1. Link Creation. Links were created from CMWD’s GIS layers of pipeline elements to represent CMWD’s recycled water system. 2. Node Creation. Nodes were automatically generated at the intersections of pipeline segments. Individual nodes representing specific components of the City’s recycled water system such as tanks and reservoirs were added. 3. Attribute Data Input. Unique attribute data was assigned to each link and node. 4. Facility Creation. Facilities were imported from the previous hydraulic model and verified through discussions with CMWD staff. 5. Operational Data. Based on the previous hydraulic model as well as discussions with CMWD operations staff, control parameters were assigned to the appropriate links and nodes. The model operates according to the operational and physical attributes assigned to each node and link. This information is used to simulate flows and pressures within the system as predicted by the model’s mathematical equations. A screenshot of the hydraulic model is shown in Figure 6.1. Figure 6.1 Screenshot of Hydraulic Model 6-4 January 2012 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 6 6.2.1 Model Links Hydraulic models consist of links and nodes to model representations of physical system components of a distribution system. Links are used to represent pipes, pumps, and control valves. Pipeline segments represent the actual transmission or distribution water pipelines. In the attribute table for each pipe, data typically includes diameter, length, C-factor, and pressure zone. The model calculator uses the attribute data to determine increases or decreases in energy levels across the link. Some of the reported output data that the model calculates for links include flows, velocities, head loss, and changes in hydraulic grade line. 6.2.2 Model Nodes Nodes represent the connections between links and may act as either a supply source, such as a reservoir or tank, or a customer demand. Nodes also define the boundaries of each link and separate links that may contain different attributes. Each node also has an elevation that fixes the elevations of the connecting link elements. Attribute data associated with each node typically includes elevation, water demand, and pressure zone. The model calculates system pressures, hydraulic grade lines, demands, and water quality parameters at each node. 6.2.3 Demand Allocation Demands were initially allocated based on historical billing records for the calendar year 2008. Demands from customer meters were allocated to the existing junction within the hydraulic model nearest the location of the meter in the City’s GIS layer of meters. Demands were updated to 2010 demands for the five largest users, and scaling of the overall demands for remaining users. Locations of meters for the five largest users were imported directly from the City’s GIS layer of meters, giving the five largest users their own nodes. These meters are assigned the same Meter ID as the City’s GIS layer and the name of the customer is included in the Description field for the junction element. As shown in Table 6.1, in addition to the demands for all of CMWD’s pressure zones, a demand of 486 gpm (0.7 mgd) was assumed for OMWD to account for the level of Mahr Reservoir. Also, 120 gpm (0.2 mgd) of CMWD’s recycled water demand represents the La Costa Resort and Spa south golf course fed by Gafner WRP and is isolated from the rest of the distribution system. January 2012 6-5 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 6 Table 6.1 Summary of Demands by Pressure Zone Recycled Water Master Plan Carlsbad Municipal Water District Pressure Zone Elevations Served (ft-msl) Average Day Demand(1) (gpm) Average Annual Demand(1) (afy) 660 240' to 460' 193 311 580 200' to 430' 142 229 550 200' to 430' 453 731 384 20' to 380' 1,476 2,381 318 50’ to 80’ 24 39 Subtotal 50' to 460' 2,287 3,690 La Costa Golf Course 61' 120 194 Subtotal (CMWD’s System) 50' to 460' 2,407 3,884 OMWD N/A 486 784 Total in Hydraulic Model 50' to 460' 2,893 4,668 Note: (1) Demands are based on 2008 data, as the spatial data for calendar year 2009 was not available at the time of this report preparation. 6.2.4 Elevation Allocation Elevations were linearly interpolated to all junctions from the City’s GIS layer of ground elevation contours. This contour layer has 2-foot intervals. 6.2.5 Attribute Data Information For junction elements, attribute data was added for the fields DMD_NODE, FACILITYID, FAC_NODE, LARGEUSER, STATUS, LOGGER, and LOGGERID. The LOGGER and LOGGERID fields were added as a part of the calibration process. Descriptions for the junction fields added to the model, as well as their sources, are shown in Table 6.2. For pipeline elements, attribute data was imported from the City’s GIS pipeline layer for the fields Diameter, Material, Zone, Year of Installation, and Facility ID. Descriptions for the fields added to the pipeline elements in the model, as well as their sources, are shown in Table 6.3. 6-6 January 2012 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 6 Table 6.2 Junction Attribute Data Fields Recycled Water Master Plan Carlsbad Municipal Water District Field Name Description Valid Entries Source DMD_NODE Indicates if a demand is placed on the junction. Boolean (Yes or No) Demand Allocation FAC_NODE Indicates if the junction is a part of a facility. Boolean (Yes or No) Generated by Consultant LARGEUSER Indicates if the junction represents the meter of a large user. Boolean (Yes or No) City’s meter GIS layer STATUS Indicates whether a facility is active in the existing system. ACT, ABAN City’s pipeline GIS layer: “STATUS” Field Table 6.3 Pipeline Attribute Data Fields Recycled Water Master Plan Carlsbad Municipal Water District Field Name Description Valid Entries Source DIAMETER Diameter of pipeline. Integers City’s pipeline GIS layer: “Diam” Field MATERIAL Pipeline material. ACP, CML&C, DI, STL, PVC (with class) City’s pipeline GIS layer: “PIPETYPE” and “PIPECLASS” Fields ZONE Pipeline pressure zone. 318, 384, 550, 580, 660 City’s pipeline GIS layer: “PressZone” Field YR_INST Year pipeline installed. Adapted from year of “ASBUILT” field. For pipelines with unknown “ASBUILT” field, used “SIGNDATE” field. Integer, 9999 used for unknown years. City’s pipeline GIS layer: “ASBUILT” and “SIGNDATE” Fields FACILITYID Unique identifier. Not included on pipelines not from the City’s GIS. WM##### City’s pipeline GIS layer: “FacilityID” Field FACILITY Indicates whether an element is part of a facility (i.e., pipeline segments used for modeling purposes rather than actual pipeline in the ground). Boolean (Yes or No) Generated by Consultant STATUS Indicates whether a facility is active in the existing system. ACT, ABAN City’s pipeline GIS layer: “STATUS” Field January 2012 6-7 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 6 6.2.6 Operational Controls Operational controls were initially obtained from the previous hydraulic model. These controls were discussed with operation staff during the Operations Workshop. The updated system controls discussed in the workshop are presented in Table 6.4. Table 6.4 Operational Controls Recycled Water Master Plan Carlsbad Municipal Water District Facility Facility Type Control Details Carlsbad WRF Discharge Pump Station • Activated by operator. • Generally two pumps on from 10:00 p.m. to 6:00 a.m. • Third pump activated when necessary. Carlsbad WRF Equalization Basin • During the winter and wet weather events, the equalization capacity is used to buffer effluent, as the ocean outfall capacity is limited. • During the summer, the equalization basin capacity is used to buffer diurnal demand variations. Avenida Encinas PRV Pressure Regulating Station • 3-inch diameter PRV set at 113 psi. • 8-inch diameter PRV set at 108 psi. Twin D Booster Pump Station • Four VFD pumps able to be controlled by flow and pressure. • Pumps would turn off if the D Tanks’ levels fall below 10 feet. Twin D Ralph Valve • 10-inch diameter FCV/PSV(1) with maximum capacity of 3,500 gpm. Twin D Potable Makeup Connection • 8-inch diameter PSV(2) with capacity of at least 3,000 gpm. • PSV is set to 74 psi. La Costa / Poinsettia PRV Pressure Regulating Station • 6-inch diameter PRV set at 90 psi. • 8-inch diameter PRV set at 85 psi. • Pressure Relief Valve (not modeled). • This station opens automatically during periods of high demand to supply Zone 384(3). 6-8 January 2012 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 6 Table 6.4 Operational Controls Recycled Water Master Plan Carlsbad Municipal Water District Facility Facility Type Control Details Bressi PS Pump Station • Three VFD pumps controlled primarily by pressure and secondarily by flow. • One 7.5 hp VFD jockey pump operated during periods of low demand(3). • 8-inch diameter Pressure Relief Valve set at 85 psi (not modeled). • This station opens automatically during periods of high demand to supply Zone 384(3). Faraday PRV Pressure Regulating Station • 6-inch diameter PRV. • 10-inch diameter PRV. • Settings for both valves are above an HGL of 384 to assist the Twin D tanks in the north portion of the 384 Zone. Calavera PS Pump Station • Three VFD pumps with a hydro-pneumatic tank. • One 5 hp VFD jockey pump operated during periods of low demand(3). • 8-inch diameter Pressure Relief Valve (not modeled). Note: (1) As discussed in Chapter 2, the valve is a combination rate of flow, pressure sustaining, and solenoid control valve, but is controlled by a SCADA based on tank level and demand. (2) As noted in Chapter 2, the valve is normally closed and can be operated remotely through SCADA. (3) Controls or facilities were modified after calibration to reflect changes in how CMWD staff operate the system. Controls for parameters not specified from the operations workshop were either based on the SCADA printouts provided by CMWD, adapted from the previous hydraulic model, or assumed from the existing system HGL. 6.3 EXISTING SYSTEM MODEL CALIBRATION The purpose of the hydraulic computer model is to estimate or predict how the water system will respond under a given set of conditions. One way to test the accuracy of the computer model is to create a set of known conditions in the water system and then compare the results observed in the field against the results of the computer model simulation using the same conditions. Field testing of the system and pulling SCADA information during that time can be a profound tool for verifying data used in the hydraulic computer model and gaining greater understanding of how the water system operates. January 2012 6-9 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 6 Field testing and SCADA review can identify errors in the data for the computer model, or it may reveal an unknown condition in the field; for example, valves reported as being open might actually be closed (or vice versa), or an obstruction could be discovered in a pipeline. This can also correct erroneous model data such as incorrect pipe diameters or connections between pressure zones. Data obtained from this process can be used to determine appropriate roughness coefficients for pipe groups based on specific information about the pipes. The roughness coefficient can vary with age and pipe material, as well as by system. Therefore, these parameters were used in combination with the field testing and SCADA results to help assign appropriate friction coefficients. 6.3.1 Field Data Gathering The field testing consisted of placing pressure loggers at various locations throughout the system. A collection of SCADA data of the system facilities during that time was downloaded. A field testing plan was developed in conjunction with CMWD staff to make efficient use of field personnel and equipment. The field data gathering plan was implemented in October 2009. For the purpose of model calibration, 15 pressure loggers were installed in the field to record system pressures. The locations of the pressure loggers are shown on Figure 6.2 and listed in Table 6.5. The detailed approach to perform field testing and obtain SCADA data for this system is provided in the “Field Testing Plan - Carlsbad Recycled Water System” (Field Testing Plan), which is included in Appendix D. Data collected from the field testing during this time is summarized in Appendix E. This data was compared to the modeling results to determine the level of calibration. The pressure loggers were set in place the evening of October 12, 2009 and recorded pressure 24 hours a day through the evening of October 21, 2009, when the loggers were removed and data downloaded. CMWD staff then pulled SCADA data from their system during this time. Unfortunately, a server error rendered automatic data gathering of the SCADA system inoperable for the time period. Data was manually copied by CMWD staff for the night of October 16, 2009, through the morning of October 18, 2009. Based on the available data, October 17, 2009 was then selected as the calibration day for the Extended Period Simulation (EPS) model calibration. The SCADA data pulled during this time is listed in Table 6.6. 6-10 January 2012 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 6 Table 6.5 Pressure Logger Locations Recycled Water Master Plan Carlsbad Municipal Water District Pressure Logger Number Location Pressure Zone Comments E6 Embarcadero Lane at Avenida Encinas 318 3 Alicante Rd. south of Lapis Rd. 384 E1 In front of 6827 Sand Aster Dr. 384 E2 1440 Sapphire Dr. 384 E5 Dahlia Way at Lowder Lane 384 E8 Armada Dr. southwest of Legoland Dr. 384 2 5927 Landau Ct. 384 Bad readings; removed from analysis. X The Crossings Dr. south of Grand Pacific Dr. 384 XX Wind Trail Way at Glen Ave. 384 12 Town Garden Rd. southwest of Alicante Rd. 550 17 Whiptail Loop and Caribou Ct. 550 E7 Rancho Santa Fe Rd. and Avenida Soledad 550 E4 Cay Dr. at Promontory Place 580 Hydro-pneumatic Zone 1 Rancho Bravado at Paseo Acampo 660 Hydro-pneumatic Zone 21 Lionshead Ave. at Eagle Dr. 660 Hydro-pneumatic Zone Note: Pressure Logger Number corresponds with numbers shown on Figure 6.2. Agua HediondaLagoon Twin "D" Tanks E l C a mi n o R e alElm A veMarron Rd Carlsbad Blvd Highla n d Dr A londra W ayPaseo Nort eCollege BlvdPalomar Airport Aviara Pkwy El Fuerte StCosta AvePoinsettia LnTam arack AveCannon Rd Calle Barcelona "C" Tank Carlsbad WRF Gafner WRP Mahr Reservoir Meadowlark WRF Rancho Santa FeCalavera PS Bressi PS "D" Tank PSPacific Ocean Encinitas Batiquitos Lagoon Buena VistaLagoon Oceanside Shadowridge WRP Corintia Meter OMWDMeter LakeCalavera El Camino RealFour SeasonsResort La Costa Resort Kemper SportsManagement Legoland Aviara ResortAssociation San Marcos Vista Encinitas Oceanside X 03 12 01 02 E1 XX E4 21 17 E5 E6 E2 E8 E7 Legend Pressure Logger Locations and IDs Pipelines by Pressure Zone318384550580660Recycled Water FacilitiesPump StationPressure Requlating Station (PRS) Meter WRF Tank Reservoir Inactive WRP Other FreewaysLocal StreetsWater BodyCarlsbad City LimitsSan Diego CountyCarlsbad Municipal Water District Boundary 0 5,000 10,000Feet Figure 6.2Calibration LocationsRecycled Water Master PlanCarlsbad Municipal Water District FILENAME: c:\pw_working\projectwise\lwang\d0102644\Figure_6_02-Calibration_Sites.mxdDATE: 5/10/2011 6-12 January 2012 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 6 This page intentionally left blank. January 2012 6-13 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 6 Table 6.6 SCADA Data Availability Recycled Water Master Plan Carlsbad Municipal Water District Facility Name Upstream Pressure Zone Downstream Pressure Zone Control Details(1) Encina/Carlsbad PS n/a 384 Pump 1 Closed Twin D Tank > 24-ft Open Twin D Tank < 20-ft Pump 2 Closed Pump 3 Closed Twin D Tank > 18-ft Open Twin D Tank < 12-ft Twin D PS 384 550 Pump 1 Closed Pump 2 Closed Pump 3 Closed Pump 4 Closed Bressi PS 550 660 Pump 1 VSP – Target Pressure = 146 psi Pump 2 Closed Pump 3 Open if zone demand > 1,200 gpm Closed if zone demand < 700 gpm Calavera PS(2) 384 580 Pump 1 Open Pump 2 Closed Pump 3 Closed Corintia FCV - 550 Open Faraday PRV 580 384 6-inch 60 psi 10-inch 70 psi La Costa PRV 550 384 6-inch 102 psi – Set based on SCADA 6-inch 90 psi 8-inch 85 psi Avenida Encinas PRV 384 318 3-inch 109 psi – Set based on SCADA 8-inch 108 psi 6-14 January 2012 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 6 Table 6.6 SCADA Data Availability (Continued) Recycled Water Master Plan Carlsbad Municipal Water District Location Upstream Pressure Zone Downstream Pressure Zone Control Details Ralph Valve(3) 550 384 55 psi – Set based on hydraulics. The Encina Basin Water Reclamation Program, Phase II Twin D Recycled Water Pump Station Plans shows that this is a 10-in combination FCV/PSV. However, CMWD staff indicate it is operated as an altitude valve. 10-inch D Tanks 384 384 Initial Level = 10.8 feet, based on SCADA C Tank 384 384 Initial Level = 13.5 feet, based on SCADA Mahr Reservoir 550 550 Levels set based on SCADA upstream pressures for Corintia Valve and pressure logger in area Meadowlark Reservoir - 550 HGL set at HWL of 318 feet. A single pump to represent two pumps. Pump Station Head with two pumps running 240 feet. Max flow of pump station with two pumps is 3,250 gpm. Based on Mahr Reservoir O&M Manual, October 2008 Note: (1) Control details were based on operational control strategy at the time of calibration, October 2009, and are modified based on staff needs. (2) As of Fall 2011, the Calavera Pump Station target psi was 177 psi, pump start was set for 145 psi, pump stop was set for 190 psi, and second call set for 700 gmp (3) As of Fall 2011, the Ralph Valve is SCADA controlled by both flow total through Corinitia meter and level in D tanks. 6.3.2 Extended Period Model Calibration One model scenario was created in the hydraulic computer model for the model calibration. The scenario was setup as an EPS run for 24 hours with demands based on actual field tank fluctuations and observed supply into the system. The goal of calibration was to have the model results within 10 percent or 5 psi of the field observations. As described previously, the recycled water demands allocated in the model were based on the average demands obtained from the geocoded billing records of calendar year 2008. The average 2008 demand without the demands of the La Costa Golf Course demands (fed by Gafner WRP) and OMWD (fed by Meadowlark WRF) is 2,287 gpm. This demand was January 2012 6-15 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 6 then scaled by 1.28 to match the total system production of 2,922 gpm recorded for October 17, 2009. The hourly supply mass balance for this day is presented in Table 6.7. Table 6.7 Mass Balance for Calibration Day Recycled Water Master Plan Carlsbad Municipal Water District Date and Time of Recordings Supply from Carlsbad WRF PS (gpm) Supply from Corintia Valve (gpm) Supply from Storage Tanks C and D (gpm) Total Supply (Demand) Balance (gpm) 10/17/09 0:00 3,352 3,571 -1,508 8,431 10/17/09 1:00 3,340 4,360 7 7,693 10/17/09 2:00 3,220 4,290 1,142 6,368 10/17/09 3:00 3,216 3,780 1,464 5,533 10/17/09 4:00 3,209 3,940 2,057 5,092 10/17/09 5:00 3,175 3,750 2,596 4,329 10/17/09 6:00 0 3,209 2,704 505 10/17/09 7:00 0 3,372 755 2,617 10/17/09 8:00 0 2,969 1,295 1,674 10/17/09 9:00 0 3,003 1,188 1,816 10/17/09 10:00 0 2,909 1,349 1,560 10/17/09 11:00 0 2,872 1,781 1,091 10/17/09 12:00 0 2,874 1,781 1,093 10/17/09 13:00 0 14 -816 830 10/17/09 14:00 0 22 -923 945 10/17/09 15:00 0 13 -923 936 10/17/09 16:00 0 11 -922 933 10/17/09 17:00 0 9 -976 985 10/17/09 18:00 0 11 -975 986 10/17/09 19:00 0 31 -1,028 1,058 10/17/09 20:00 0 559 -1,027 1,586 10/17/09 21:00 0 854 -1,945 2,799 10/17/09 22:00 3,193 1,247 -2,321 6,761 10/17/09 23:00 3,172 1,600 274 4,498 Average 1,078 2,053 210 2,922 6-16 January 2012 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 6 The diurnal demand curves presented in Figure 6.3 were prepared from the supply mass balance for the two days for which SCADA data was available. It should be noted that, as SCADA data was not gathered after 1:00 p.m. for Sunday, October 18, 2009, the data from Saturday, October 17, 2009 was used for the last six hours of the weekend diurnal demand curve. 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 Ratio of Hourly Demand to Average Demand for the DayHour of Day Weekday Diurnal Weekend Diurnal Figure 6.3 System Wide Diurnal Demand Patterns The diurnal pattern of October 17, 2009 was then used to develop diurnal curves for individual pressure zones by adjusting for diurnal patterns that were developed for the two golf courses that take recycled water during the daytime hours to fill the on-site lakes. The diurnal curves used in the hydraulic model are smoothed out compared to the raw data shown in Figure 6.3 as the actual demand variation will vary on a daily basis and simplified curves are considered more appropriate for planning purposes. The diurnal curves presented in Figure 6.3 indicate that CMWD’s demands peak at about 11:00 p.m. and begin to drop off in the early morning hours. Demands during the day are minimal until the evening peak begins after 10:00 p.m. When compared with the typical diurnal curves presented in Chapter 3, it can be concluded that the majority of CMWD’s nightly irrigation demands occur during the early night hours, between 10:00 p.m. and 3:00 a.m., and are not evenly distributed across the 8-hour irrigation period. January 2012 6-17 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 6 Hazen-Williams roughness coefficients (C factors) were assigned. These C factors were developed from standard published values for pipes of similar material and age and are presented in Table 6.8. Table 6.8 Pipeline Roughness Coefficients Recycled Water Master Plan Carlsbad Municipal Water District Class Number Pipe Material(1) Installation Year Age (Years) Percent of Total (%) Typical C Factor Range Selected C Factor 1 ACP after 1970 0-35 3 130–150 130 2 CML&C STL after 1970 0-35 15 140–150 130 3 DIP 1985 - 2004 7-26 7 130–150 130 4 PVC All All 75 130–160 130 5 HDPE 2000 - 2004 7-11 <1 120–150 130 Note: (1) ACP: asbestos cement pipe CML&C STL: cement mortar lined steel DIP: ductile iron pipe PVC: polyvinyl chloride The calibration process required that the model simulations duplicate the boundary conditions observed at the time of each test. Boundary conditions include sources of supply, storage facilities, and other locations where water flows into or out of the distribution system. The boundary conditions were set based on SCADA data from the City’s system during the pressure logger data retrieval. Where significant differences were revealed between the model results and the field observations during calibration, the model data was rechecked against known data to evaluate the accuracy of the data. This could include checking pipe diameters and similar data. If this data appeared to be correct, additional steps were taken to verify connections between pipes, verify pressure zone boundaries, and perform similar checks. Adjustments made to the model during the calibration process included: • Establishing demand patterns / diurnal curves for users in the upper zone, lower zone, hydro-pneumatic zones, and the golf courses known to irrigate during the day. The individual demand patterns / diurnal curves were calculated such that the overall aggregate weighted demand pattern would match the mass balance calculated for the calibration period. • Updating the hydraulic model to incorporate changes to the distribution system for which CMWD provided drawings. • Adding hydro-pneumatic tanks to the Calavera PS and Bressi PS to better reflect how these facilities operate. 6-18 January 2012 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 6 • Changing the Corintia Meter from a flow control valve to a throttle valve. • Adding minor losses to the Corintia Meter vault and some pipelines to limit the amount of flow from Mahr and allow more pumped flow from the Carlsbad WRF. • Revising the assumed OMWD demand pattern based on the levels in Mahr Reservoir relative to the flow through the Corintia Meter, discussions with OMWD staff, and evaluation of OMWD’s 2004 Recycled Water Master Plan. • Alterations of elevations in the vicinity of Whiptail Loop north of Faraday Avenue to reflect grading changes. During the calibration process, it was determined that grading for a development had altered the ground elevations reflected in the City’s contour layer. Elevations were adjusted accordingly to reflect the grading. The calibration process attempted to correct any errors found in the model data before calibrating friction coefficients or suggesting that unknown field conditions (such as a closed main line valve) might exist. 6.3.3 Extended Period Calibration Results Calibration results were analyzed by comparing the differences between field observed pressures and model results for each pressure logger, pump station, and reservoir. These comparisons were made after errors were corrected and adjustments were made in the model. Charts showing the comparison of model results to field data for each logger and facility are included in Appendix F. Figure 6.4 presents the comparison of model results to field data for three storage reservoirs; D Tanks, C Tank, and Mahr Reservoir. A shown in Figure 6.4, the levels within the reservoirs follow the trending of the field data. The model results for the pressure loggers, pump stations, and reservoirs are generally judged to fall within 10 psi of the field data. 6.3.3.1 Summary of Calibration Results The locations of the remote pressure loggers that were installed in the system to gather field data are shown on Figure 6.2. The calibration results of these individual pressure loggers, as well as the tank levels, pump stations, and pressure regulating valves are presented in Appendix F. Based on the results presented in Figure 6.4 and in Appendix F, it can be concluded that the model results closely match field conditions for most calibration points. Hence, the hydraulic model is therefore considered calibrated and can be used to evaluate the system hydraulics under existing and future demand conditions, identify deficiencies, and size facilities to address deficiencies and serve the future customers, while meeting the planning and evaluation criteria outlined in Chapter 7 of this report. January 2012 6-19 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 6 0 5 10 15 20 25 30 35 Level (ft)TimeMahr Reservoir -SCADA Twin "D" Tanks -SCADA "C" Tank -SCADA Mahr Reservoir -Model Twin "D" Tanks -Model "C" Tank -Model Figure 6.4 Reservoir Calibration Results It is important to note that model calibration for any water system is an ongoing effort. As changes in the system occur from changing demands, new infrastructure development, or changing operational settings, the model must be periodically updated and checked to confirm that the model results are in agreement with field measurements. Therefore, this calibration effort serves as a baseline for future calibration efforts. 6.3.4 Water Quality Calibration Water quality samples were obtained by CMWD staff on October 14, 2010. Initial model calibration plans (as outlined in Appendix D) were to calibrate the water quality and hydraulic components of the model over the same time period. Due to a server outage, the SCADA data was unavailable and the hydraulic calibration was conducted with data for October 17, 2009. Hence, the conditions used for the hydraulic model calibration do not coincide with the day that the water quality samples were taken. It was necessary to make the assumption that the system operations of the recycled water distribution system are similar from day to day and that the hydraulic conditions on the day of water quality sampling (Wednesday October 14, 2009) were sufficiently similar to the day of hydraulic calibration (Saturday October 17, 2009). It should be noted that water quality modeling is extremely sensitive to the hydraulic conditions in the distribution system. The 6-20 January 2012 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 6 results of this water quality calibration should take this into consideration. Table 6.9 presents chlorine residual levels sampled at each of the sampling sites. Table 6.9 Water Quality Samples Recycled Water Master Plan Carlsbad Municipal Water District Sample Location ID Location Zone Time(1) Chlorine Residual (Total Chlorine mg/L) A Tamarack west of Cay Dr. 580 09:00 0.0 B Transmission Main from C Tank 384 09:25 0.0 C Cannon Rd. northeast of Faraday Av. 384 09:35 0.2 D Faraday Av. and Priestly Dr. 550 09:47 0.2 E Melrose Dr. between Faraday Av. and Priestly Dr. 660 10:00 5.5 F Aviara Py., between Ambrosia Ln. and Mimosa Dr. 384 10:13 1.1 G Corintia St. west of Melrose Dr. N/A 10:25 3.0 H The Crossings, south of Grand Pacific Dr. and north of Palomar Airport Rd. 384 11:37 2.0 I Transmission Main near D Tank 384 11:09 3.0 J Avenida Encinas and Embarcadero Ln. 384 11:25 3.9 K Transmission Main from Mahr Reservoir N/A 10:52 4.2 Note: (1) All water quality samples taken on October 14, 2010. As seen in Table 6.9, the sampled chlorine residuals ranged from 5.5 mg/L downstream of Bressi Pump Station to undetectable levels in the north areas of CMWD. The locations and levels of each of the sampled residuals are shown on Figure 6.5. Note that Sample E exceeds the sampled chlorine residual at either source (Carlsbad WRF and Meadowlark WRF), suggesting that the chlorine residual at the sources must have been fluctuating to higher levels prior to sampling (all samples were taken within a few hours). At Carlsbad WRF, the average chlorine residual between September 15 and September 30, 2009 was 9.1 mg/L. For Meadowlark WRF, the average minimum chlorine residual during August 2009 was 16.3 mg/L. However, discussions with City staff have indicated that chlorine residual is reduced to limit the chlorine residual to less than 10 mg/L. At the time of calibration, Meadowlark WRF staff reduced the chlorine residual considerably, but without evaluating the resulting chlorine residual on a continuous basis. The modeled initial source chlorine residual was therefore adjusted iteratively to match the sampled chlorine residual of 3.0 mg/L at the location of Site G. After this iterative process, a chlorine residual of 4.5 mg/L was used at Meadowlark. "C" Tank Carlsbad WRF Gafner WRP Mahr Reservoir Meadowlark WRF Agua HediondaLagoon Twin "D" Tanks C a min o R e alElm A veMarron Rd Carlsbad Blvd Hig hla n d D r A londra W ayPaseo NorteCollege BlvdPalomar Airport Aviara Pkwy El Fuerte StCosta AvePoinsettia LnTam arack A veCannon Rd Calle BarcelonaRanc ho Santa FeCalavera PS Bressi PS "D" Tank PSPacific Ocean Encinitas Batiquitos Lagoon Buena VistaLagoon Oceanside Shadowridge WRP OMWDMeter Corintia Meter LakeCalavera Four SeasonsResort La Costa Resort Kemper SportsManagement Legoland Aviara ResortAssociation San Marcos Vista Encinitas Oceanside I1.03.0 H0.32.0 A0.00.0 J3.83.9 F0.31.1 E1.55.5 D2.40.2 B0.00.0 K3.04.2 C0.10.2 0 5,000 10,000Feet Figure 6.5Water Quality Calibration ResultsRecycled Water Master PlanCarlsbad Municipal Water DistrictFILENAME: c:\pw_working\projectwise\lwang\d0102644\Figure_6_05-Water Qualityy_Calibration_Results.mxdDATE: 5/10/2011Pipelines by Pressure Zone 318 384 550 580 660 Recycled Water Facilities Pump Station Pressure Requlating Station (PRS) Meter WRF Tank Reservoir Inactive WRP Other Freeways Private Pipeline Local Streets Carlsbad City Limits San Diego County Carlsbad Municipal Water District Boundary Poor Legend Fair Good Calibration Correlation Residual Sampling Sites ID Sample ResidualModel ResidualA#.##.# 6-22 January 2012 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 6 This page intentionally left blank. January 2012 6-23 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 6 While some chlorine decay information can be calculated based on the sample times and locations, detailed hydraulic information on transients within the distribution system is not available. A chlorine jar test would allow estimation of the decay coefficient by removing hydraulic variation within the system. However, a chlorine jar test data was not available. In absence of chlorine jar test data, a global bulk chlorine decay coefficient of -0.05 along with a default global wall chlorine decay coefficient of -0.15 were used. 6.3.5 Water Quality Calibration Results Table 6.10 presents model predictions of water quality chlorine residual samples. For each model prediction, the correlation of the model predictions to the sampled chlorine residuals is noted with a qualitative statement. Good means that the model prediction and sampled chlorine residual varied by less than 10 percent. Fair means that the model prediction and sampled results varied between 10 and 50 percent. Poor means that the difference between model prediction and sampled results was greater than 50 percent. Table 6.10 Water Quality Calibration Results Recycled Water Master Plan Carlsbad Municipal Water District Sample Location ID Pressure Zone Sampled Chlorine Residual (Total Chlorine mg/L) Model Predicted(1) Chlorine Residual (Total Chlorine mg/L) Correlation of Model Prediction to Samples(2) A 580 0.0 0.0 Good B 384 0.0 0.0 Good C 384 0.2 0.1 Fair D 550 0.2 2.4 Poor E 660 5.5 1.5 Good F 384 1.1 0.3 Good G N/A 3.0 3.9 Fair H 384 2.0 0.3 Poor I 384 3.0 1.0 Poor J 384 3.9 3.8 Good K N/A 4.2 3.0 Fair Notes: 1) All water quality samples taken on October 14, 2010. The hydraulic model EPS calibration was conducted for October 17, 2010. Hydraulic conditions of October 17, 2010 were used for this analysis. It should be noted that water quality modeling can be extremely sensitive to the hydraulic conditions in the distribution system and the results of this water quality calibration should take this into consideration. 2) Good = Chlorine residual variance < 10 percent; Fair = 10-50 percent; and Poor = greater than 50 percent. 6-24 January 2012 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 6 As shown in Table 6.10, model predictions for chlorine residual deviated significantly from the sampled chlorine residuals. The most significant deviations were in the upper pressure zones of the distribution system. Average chlorine residuals for the entire distribution system are shown by pipeline segment on Figure 6.5. The water quality component of the model was not further calibrated. CMWD initially planned to repeat the water quality sampling. However, with the primary purpose of the model being the sizing of future pipelines, it was decided that the hydraulics of the model were accurate enough for system analysis and planning. 6.4 FUTURE SYSTEM MODEL CREATION The future system hydraulic model was created to evaluate and size expansion alignments, pump station improvements, and storage recommendations discussed in Chapter 9. Development of the future system model consisted of the following steps: • Determine preliminary alignments of expansion segments based on locations of the potential customers from the customer database • Import preliminary expansion segments into the hydraulic model • Assign demands from the customer database to the expansion segments (excluding customers too far away to be included in expansion segments, adding demands for vacant land, and remove demands from ultimate system for temporary agricultural demands) • Increase capacity of recycled water sources, pump stations, and storage based on preliminary analysis in Chapter 9 • Increase sizing of pipelines to resolve deficiencies in the proposed system The future system model was created based on expansion laterals to reach as many customers as possible with minimal new pipeline length. The specific alignments will be discussed in Chapter 9. Customer laterals are drawn to the customer database node within the model. However, as will be discussed in more detail in Chapters 9 and 10, costs for the customer laterals are developed based on the number of retrofit customers rather than actual pipeline length. Thus, the lengths of the customer laterals are not included in development of the expansion segment lengths. A pipeline set was created to account for the potential decrease in friction factors as pipelines in the distribution system age. As outlined in Chapter 7, a Hazen-Williams roughness coefficient of 120 was used for pipelines over 20 years of age. For the future system, all existing pipelines were assumed to be greater than 20 years of age by this time. Where pipeline alignments fell within the City’s boundary, junction elevations were interpolated from the elevation contours provided by CMWD. For pipeline alignments outside the coverage of the elevation contours provided by CMWD, approximate elevations were calculated from data obtained from USGS (USGS, 2010). January 2012 7-1 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 7 Chapter 7 PLANNING AND EVALUATION CRITERIA 7.1 INTRODUCTION This chapter presents the planning and evaluation criteria that were used to identify system deficiencies in the Carlsbad Municipal Water District’s (CMWD) existing system and to size system expansions. The planning and evaluation criteria discussed in this chapter include system pressures, pipelines, storage reservoirs, and booster pumping stations. The criteria discussed herein are also summarized at the end of this chapter in Table 7.1. 7.2 SYSTEM PRESSURES The recycled water system pressure is ideally designed to be slightly lower than the potable water system pressure. This pressure differential reduces the risk of potable water contamination from recycled water, in the event that an adjacent recycled water main breaks. However, this requirement often cannot be met due to the following two reasons: 1. System pressures in water systems vary and pressure zone boundaries of potable and recycled water systems typically do not overlap. 2. It is preferred to maintain a minimum pressure in the recycled water system of approximately 60 pounds per square inch (psi) to meet the operating requirements for most sprinkler systems. However, the minimum pressure in potable water systems is typically 40 psi. As the chance of cross contamination is minimal due to disinfection and a minimum horizontal separation of 10 feet between potable and recycled water pipelines, it is assumed that the layout of the recycled water system expansions does not need to be coordinated with the existing potable water system pressure ranges. The minimum system pressure used for pipeline sizing in this RWMP is 60 psi under peak hour demand (PHD) conditions. While the maximum system pressure under minimum day demand (MinDD) conditions is limited to 80 psi by the California Plumbing Code (CPC, 2007 – Section 608.2), CMWD does not anticipate dual plumbing, or other uses which would include piping inside a building. Thus, 125 psi will be used as the maximum pressure criteria, above which a pressure regulator will be considered at the meter connections. In locations with pressures exceeding 150 psi, the pipeline class used for construction of the pipeline segments should be considered. 7-2 January 2012 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 7 7.3 PIPELINE VELOCITIES AND HEAD LOSS The maximum velocity in pipelines should not exceed 7 feet per second (ft/s) under PHD conditions in all existing pipelines, regardless of diameter. Proposed distribution pipelines, those 12 inches and less in diameter, will be sized such that the maximum velocity should not exceed 7 ft/s under PHD conditions. Proposed transmission mains, those greater than 12 inches in diameter, will be sized such that the maximum velocity should not exceed 5 ft/s under PHD conditions. A lower pipeline velocity is used for transmission mains to avoid excessive sloping of the hydraulic grade line across pressure zones. For existing pipelines, the maximum head loss should not exceed 7 feet per thousand feet (ft/1,000 ft) under PHD conditions with the entire distribution network in service. Proposed pipelines will be sized so that the maximum head loss should not exceed 5 ft/1,000 ft. As discussed in Chapter 6, the hydraulic model uses the Hazen-Williams hydraulic calculation to calculate head loss. A Hazen-Williams roughness coefficient of 120 is used for pipelines greater than 20 years in age, and a roughness coefficient of 130 is used for pipelines less than 20 years in age. Most of CMWD’s pipelines are relatively new and constructed of PVC material, for which a roughness coefficient of 140 is typically used in design of pipelines. The roughness coefficients used in this planning study are lower than that used in design of pipelines to account for potential biogrowth associated with recycled water systems with lower chlorine residuals, minor losses, which are not accounted for individually in this level of planning study, and other potential unknown conditions. 7.4 PIPELINE SIZING CRITERIA Pipeline sizing is based on several factors including: • Demand conditions • Pipeline velocity • Pipeline head loss Pipelines are selected so that they do not exceed velocity and head loss criteria under PHD conditions. When a pipeline exceeds the velocity or head loss criteria during PHD, it is upsized to the next standard size. Velocity criteria are discussed above. The minimum pipeline size of new distribution pipelines, excluding service laterals, is 4 inches in diameter, which is used for dead-end pipelines less than 1,000 feet in length. CMWD uses 6-inch pipelines for non-looped, dead-end pipelines greater than 1,000 feet in length and 8-inch diameter pipelines for looped pipelines. January 2012 7-3 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 7 The standard sizes used for pipelines include 4-inch, 6-inch, 8-inch, 12-inch, 16-inch, 20-inch, 24-inch, 30-inch, and 36-inch diameter pipelines. 7.5 STORAGE SIZING CRITERIA To operate a recycled water system with reservoirs that are supplied from the water reclamation facilities, two types of storage are required and an additional type of storage is used within CMWD’s system. These are: 1. Operational Storage. The storage required to buffer demand fluctuations under maximum day demand (MDD) conditions. The volume required for this storage component is dependent upon the hourly variation of the customer’s demand and the variation of flow from the various water reclamation facilities. 2. Short-term Emergency Storage. The storage volume required to protect reservoirs from complete drainage. Emergency storage provides a few hours to respond to an emergency and make operational adjustments without immediate interruption of service. 3. Seasonal Storage. The storage volume used to buffer seasonal peak flows, allowing the system to supply customer demands in excess of the maximum daily supply capacity of CMWD’s supply sources. Seasonal storage allows recycled water to be stored during periods of low demands, such as winter months, to be used during periods of high demands, such as summer months. Note that seasonal storage functions as a supply, and thus criteria for sizing seasonal storage are not applicable unless seasonal storage was sized to meet a specific supply requirement. Seasonal storage is discussed in more detail in Chapter 4. 7.5.1 Operational Storage Operational storage is calculated based on the estimated recycled water demand of the existing customers and their associated diurnal patterns. Figure 7.1 presents an analysis based on CMWD’s system diurnal curve on October 16 and 17, 2009. The average system demand in this 24-hour period was 4.9 mgd, which equates to an average demand of 3,413 gpm. Assuming demands in excess of the average demand for the day should be provided by operational storage, the area above the average demand line represents the amount of demand that must be provided from storage. This area represents approximately 1.7 million gallons (MG), which is about 33 percent of the average demand over the course of a day (1.7 MG / 4.9 mgd). 7-4 January 2012 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 7 0 1,000 2,000 3,000 4,000 5,000 6,000 7,000 8,000 9,000 10,000 7:00 PM 8:00 PM 9:00 PM 10:00 PM 11:00 PM 12:00 AM 1:00 AM 2:00 AM 3:00 AM 4:00 AM 5:00 AM 6:00 AM 7:00 AM 8:00 AM 9:00 AM 10:00 AM 11:00 AM 12:00 PM 1:00 PM 2:00 PM 3:00 PM 4:00 PM 5:00 PM 6:00 PMFlow (gpm)Time of Day Demand Met by Supply Required Storage Volume Ave Demand Demand Required Storage Volume 1.7 MG(33%) Figure 7.1 Operational Storage Requirement CMWD’s operational storage is currently provided at various locations in the recycled water distribution system and includes the following: • C Tank • Twin D Tanks • Mahr Reservoir In addition, supply from the treatment facilities is buffered by equalization basins consisting of: • Mahr Reservoir • Equalization basin at Carlsbad WRF Note that Mahr Reservoir is included in both categories, as CMWD does use Mahr Reservoir for daily peaking of the 550 zone. For the purposes of this study, the supply equalization basin at Carlsbad WRF was not counted as operational storage. But functionally, CMWD can use this facility if necessary. January 2012 7-5 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 7 7.5.2 Short-term Emergency Storage Short-term Emergency Storage is required to provide operational flexibility during emergencies, such as a temporary shutdown of any of the WRPs or pump stations. Based on an emergency response time of 4 hours, the capacity of all reservoirs should include an additional 17 percent of MDD (4 hrs / 24 hrs = 17% of MDD, which is equivalent to 80 minutes of PHD) to provide buffer capacity for emergency needs. 7.5.3 Seasonal Storage Seasonal storage is treated as a source of supply and is discussed in more detail in Chapter 4. 7.5.4 Summary In summary, the operational and emergency storage requirements are 33 percent of MDD and 17 percent of MDD, respectively. For planning purposes, it is therefore recommended that CMWD have a total of 50 percent (33% + 17%) of MDD available for storage. 7.6 PUMP STATION SIZING CRITERIA Two different pump station (PS) sizing criteria were used for the system analysis in this study. The criterion that should be applied for the sizing of a PS is dependent upon the location of reservoir storage in the zone that the PS pumps into. The two criteria are: • Pressure zones with gravity reservoir storage. These zones have the benefit that reservoirs provide additional supply during the peak hours of MDD (reservoir drainage) and provide buffer capacity during the minimum hours of MDD (reservoir filling). This allows pump station sizing for the average hour demand of MDD. Hence, all pump stations that pump into a zone with gravity storage are sized for MDD. • Pressure zones without gravity reservoir storage. These zones do not provide the benefit of additional supply from reservoirs during the peak hours of MDD. Hence, all pump stations that pump into a zone without gravity storage (closed system) need to be sized for PHD with a standby pump unit. The total pumping capacity of a PS needs to be sufficient to serve the required demand with the largest pump unit out of service, so that one pump unit can be designated as a spare to accommodate repairs and maintenance activities without interruption of system operations. However, this criterion was not applied to the Carlsbad WRF PS, rated at 10,000 gpm, as CMWD has incorporated storage in the pressure zone into which the Carlsbad WRF PS pumps. 7-6 January 2012 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 7 7.7 SYSTEM RELIABILITY CRITERIA System reliability criteria are intended to evaluate a recycled water system’s ability to meet recycled water demands during events such as power outages. While less critical than in a potable water system, extended outages could result in costly loss of property, as irrigation may not be available for customer’s landscaping, especially in the cases of customers such as golf courses, where the landscaping represents an extensive investment. As CMWD begins to connect users of different usage classes, such as industrial, dual plumbing, or fire water usage types, system reliability will be even more important. CMWD’s customers are required to maintain separation of the recycled water and potable water systems. Hence, CMWD’s customers do not have potable water backup supplies with the exception of the golf courses that blend recycled water and potable water in their lakes using an air gap for the potable water supply to avoid cross connections. In case of a power outage, the majority of CMWD’s recycled water customers can be served from gravity storage and through PRV stations. The emergency storage capacity discussed in Section 7.5 provides 4 hours of supply under MDD conditions to make operational adjustments, such as the installation of a portable backup power generator. 7.8 SUMMARY PLANNING AND EVALUATION CRITERIA The evaluation and sizing criteria described in this chapter are summarized in Table 7.1. Table 7.1 System Evaluation Criteria Recycled Water Master Plan City of Carlsbad Parameter Evaluation Criteria Demand Condition System Pressure Minimum System Pressure 60 psi Peak Hour Demand Maximum System Pressure(1) 125 psi Minimum Hour Demand Maximum System Pressure(2) 150 psi Minimum Hour Demand Pipeline Velocity Evaluation of Existing Pipelines: Max. Velocity 7 ft/s Peak Hour Demand Sizing of New Pipelines: Max. Velocity (Diameter > 12-inch) 5 ft/s Peak Hour Demand Max. Velocity (Diameter ≤ 12-inch) 7 ft/s Peak Hour Demand Pipeline Head Loss Evaluation of existing pipelines: Max. Head Loss 7 ft/1,000 ft Peak Hour Demand Sizing of new pipelines: Max. Head Loss 5 ft/1,000 ft Peak Hour Demand January 2012 7-7 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 7 Table 7.1 System Evaluation Criteria Recycled Water Master Plan City of Carlsbad Friction Factor (Hazen-Williams) Existing Pipelines (< 20 years old) 130 All conditions Pipelines (20-50 years old) 120 All conditions Storage Volume Operational Storage 33% of MDD(3) Maximum Month Demand Short-term Emergency Storage 17% of MDD(4) Maximum Month Demand Total Storage 50% of MDD(2) Maximum Month Demand Pump Station Standby Capacity For Zones with Gravity Storage Meet MDD with largest pump unit OOS(5) Maximum Month Demand For Zones without Gravity Storage Meet PHD with largest pump unit OOS(5) Peak Hour Demand Backup Power Connection for Portable Generator (in Zones without Gravity Storage) Peak Hour Demand Notes: (1) Maximum pressure without pressure reducing valves; higher pressures are acceptable if pressure reducing valves are installed at the meter connection (CPC, 2007). (2) Maximum pressure for standard pipelines. For areas with higher pressures, the pipeline class (pressure rating) should be considered. (3) Based on the City’s diurnal pattern on October 16 - 17, 2009. (4) Based on an emergency response time of 4 hours (4 hours divided by 24 hours). (5) OOS = out of service 7-8 January 2012 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 7 This page intentionally left blank. January 2012 8-1 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 8.doc Chapter 8 EXISTING SYSTEM EVALUATION This chapter evaluates the existing system to identify system constraints and inefficiencies that should be resolved for optimal system operation and preparation for future system expansion. This chapter consists of the following five sections: • Hydraulic Analysis • Storage Analysis • Pump Analysis • Energy Analysis • Water Quality Analysis Where appropriate, recommendations are made for addressing system deficiencies or improving system performance. Capital cost estimates are provided for each recommendation. The chapter concludes with a summary of system inspection requirements. A detailed description of the existing system is included in Chapter 2. 8.1 HYDRAULIC ANALYSIS A hydraulic analysis was performed on the existing system for Minimum Day Demands (MinDD), Average Annual Demands (AAD), and Maximum Month Demands (MMD). Diurnal curves that included peak hour demand were used to account for the variation of demand throughout the day for the MinDD, AAD, and MMD scenarios. System analysis criteria are discussed in Chapter 7 and are summarized in Table 8.1. Figure 8.1 shows locations with pressures exceeding 125 psi. Figure 8.2 shows locations with low pressures below 60 psi and pipes with velocities and head losses exceeding the stated criteria in Table 8.1. 8.1.1 Distribution System Using the hydraulic model, the distribution system was evaluated under MinMD, AAD, and MMD demand conditions. The model predicted both high and low pressure deficiencies under the evaluated conditions. 8-2 January 2012 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 8.doc Table 8.1 System Evaluation Criteria Recycled Water Master Plan Carlsbad Municipal Water District Parameter Evaluation Criteria Demand Condition System Pressure Minimum System Pressure 60 psi Peak Hour Demand Maximum System Pressure(1) 125 psi Minimum Hour Demand Maximum System Pressure(2) 150 psi Minimum Hour Demand Pipeline Velocity Evaluation of Existing Pipelines: Max. Velocity 7 ft/s Peak Hour Demand Sizing of New Pipelines: Max. Velocity (Diameter > 12-inch) 5 ft/s Peak Hour Demand Max. Velocity (Diameter ≤ 12-inch) 7 ft/s Peak Hour Demand Pipeline Head Loss Evaluation of existing pipelines: Max. Head Loss 7 ft/1,000 ft Peak Hour Demand Sizing of new pipelines: Max. Head Loss 5 ft/1,000 ft Peak Hour Demand Notes: (1) Maximum pressure without pressure reducing valves; higher pressures are acceptable if pressure reducing valves are installed at the meter connection (CPC, 2007). (2) Maximum pressure for standard pipelines. For areas with higher pressures, the pipeline class (pressure rating) should be considered. Areas exceeding the 125 psi criteria are shown in Figure 8.1 by maximum pressure. As shown in the evaluation criteria in Table 8.1, the maximum pressure was evaluated under MinMD conditions and consisted of two criteria, a 125 psi maximum above which service lateral pressure regulating devices should be considered and a 150 psi maximum above which consideration should be made for higher pipeline pressure classifications during design. Note that junctions that are a part of facilities (e.g., discharge headers for pump stations) were excluded from this analysis and are not shown as deficient. Approximately 35 percent (by demand) of the system exceeds the maximum pressure criteria of 125 psi. Approximately 7 percent (by demand) of the system exceeds the second maximum pressure criteria of 150 psi, and the associated pipelines should be designed accordingly for higher pressures. Low-pressure deficiencies were also identified. Areas with pressures below 60 psi are shown on Figure 8.2. The majority of the low pressure deficiencies are not located near pipelines with velocity or head loss deficiencies, indicating that low pressures in the system are predominantly due to higher elevations within the existing pressure zones, rather than localized head loss due to pipeline velocities during periods of high demand. "C" Tank Carlsbad WRF Gafner WRP Mahr Reservoir Meadowlark WRF Agua HediondaLagoon Twin "D" Tanks Calavera PS "D" Tank PS Pacific Ocean Encinitas Batiquitos Lagoon Buena VistaLagoon Oceanside Faraday PRS Avenida Encinas PRS La Costa PRS Corintia Meter OMWDMeter LakeCalavera EL CAMINO REALCANNON R D POINSETTIA L NCOLLEGE B L PALOMAR A I R P O R T R D A L G A R D C A R L S B A D BL A VI ARA P Y MELR O S E D R L A COSTA AV RANCHO SANTA FE RDOLIVENHAIN R D CA M I NO JUNIPERO Legend Nodes with High Pressures125 - 150 psi151 - 175 psi 176 - 200 psiFacilities Meter Pump StationPressure Regulating Station WRF Tank Reservoir Recycled Water PipelinesDiameterLess than 6" 6" to 8"10" to 14" 16" and largerOtherFreeways Major RoadsLocal Streets Carlsbad Municipal Water District Boundary Water Body Carlsbad City Limits San Diego County 0 5,000 10,000Feet Figure 8.1Pressures Greater than 125 psi Carlsbad Municipal Water District FILENAME: c:\pw_working\projectwise\lwang\d0102644\Figure_8_01 Pressure Exceeding 125 psi VerB.mxdDATE: 5/11/2011 8-4 January 2012 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 8.doc This page intentionally left blank. "C" Tank Carlsbad WRF Gafner WRP Mahr Reservoir Meadowlark WRF Agua HediondaLagoon Twin "D" Tanks Calavera PS Bressi PS "D" Tank PS Pacific Ocean Encinitas Batiquitos Lagoon Buena VistaLagoon Oceanside Faraday PRS Avenida Encinas PRS La Costa PRS Meadowlark PS The Crossings Corintia Meter OMWDMeter D C E LakeCalavera Park HyattAviara Resort La Costa Resort BA Legoland Aviara ResortAssociationEL CAMINO REALCANNON RD POINSETTIA L N CO L LEGE BLPALOM A R A IR P O R T RD A L G A R D C A R L S B A D B L AVIA RA PYMELR O S E D R LA COSTA AV RANCHO SANTA FE RDOLIVENHAIN R D CA M I NO JUNIPERO Under AAD, MMD Under MMDModel Nodes with Low PressuresUnder AAD, MMD, and MinMDUnder AAD, and MMDUnder MMDRecycled Water Pipelines (by Diameter)Less than 6"6" to 8"10" to 14"16" and largerWater System Facility Meter Pump Station (PS)Pressure Regulating Station (PRS) WRF/WRP Tank Reservoir Other FreewaysLocal StreetsWater Body Carlsbad City LimitsSan Diego CountyCarlsbad Municipal Water District Boundary 0 5,000 10,000Feet Figure 8.2Low Pressure and High VelocitiesRecycled Water Master PlanCarlsbad Municipal Water District FILENAME: c:\pw_working\projectwise\lwang\d0102644\Figure_8_02-Low_Pressure_and_High_Velocities.mxdDATE: 5/12/2011Legend Model Pipes with High Velocities / High Headloss Under AAD, MMD Under MMD "D" Tank PS Four Seasons PT12'' 12''14'' 6''12"18"18"4" Four SeasonsResort A Aviara ResortAssociation BPOINSETTIA LNBLACK RAIL RDDOCENA CAM DE LAS ONDASMALLEEAVIARA PY KESTREL DR8'' 12'' 10'' 1 4 ''24''8'' 2 4 ''6'' 8''24'' 8-6 January 2012 - DRAFT pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 8.doc This page intentionally left blank. January 2012 8-7 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 8.doc The hydraulic model predicted head loss and velocity deficiencies at a total of 16 locations, which are shown in Figure 8.2. In addition, head loss or velocity were predicted to exceed criteria in pipelines at two locations which are a part of facilities. These pipeline segments were identified at the Calavera Pump Station hydropneumatic tank and the discharge pipeline from Meadowlark WRF. Since high head loss could be expected at each of these locations, these segments were excluded from analysis. Head loss and velocity deficiencies in 11 locations were along pipelines serving only one customer. These deficiencies were evaluated on a case-by-case basis. It was determined that the model predicted that pressure was reduced below the minimum pressure criteria of 60 psi at the point of connection at only one location, the Park Hyatt Aviara Resort. Pressure at the meter was predicted to fall to 42 psi under AAD conditions and 29 psi under MMD conditions. It should be noted that the assumed diurnal pattern for the Park Hyatt Aviara Resort may be different during MMD conditions, with irrigation taking place over a longer portion of the day. Since this is one of CMWD’s largest and most long-term users, it is likely that any problems with low pressure would have already been brought to CMWD’s attention. However, recommendations for two of the deficiencies discussed below are anticipated to improve the pressure at this location. Three locations of high head loss, indicated as C, D, and E on Figure 8.2, were located away from areas of low pressure and are assumed to have limited impact on the system and not recommended for replacement at this time. However, if one of these pipes should require replacement due to normal maintenance, then the new pipe should be of a larger diameter. The locations of the remaining two deficiencies are along Aviara Parkway. These two deficiencies are listed in Table 8.2 and identified on Figure 8.2 by the corresponding Map IDs A and B. Table 8.2 Pipeline Deficiency Locations Recycled Water Master Plan Carlsbad Municipal Water District Map ID Street From To Zone Exist Diam. (in) Repl. Diam. (in) Length (ft) Low Pressure Nearby A Aviara Pkwy 300' s/o Poinsettia Ln Kestrel Dr 384 6 12 1,100 Y B Aviara Pkwy 300' nw/o Black Rail Ct Four Seasons Pt 384 12 16 1,100 Y As shown in Table 8.2, a total of 2,200 feet of pipeline along Aviara Parkway is predicted, at least in part, to cause pressure losses in the area. While velocity in these stretches of pipeline reach a maximum of 6.3 ft/s under peak hour demand (PHD) conditions, head loss reaches 13 feet per thousand feet, with total head loss over the deficient pipeline segments of 25 feet (10.8 psi). It should be noted that, according to the City’s GIS pipeline layer, the 8-8 January 2012 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 8.doc diameters in the entire 4,200-foot stretch of pipeline along Aviara Parkway from Poinsettia Lane to Four Seasons Point range in diameter from 6 inches to 14 inches, transitioning in diameter four times over this stretch before connecting to the 14-inch pipeline extending east from Four Seasons Parkway. Note that much of this stretch was constructed in 1989. A pressure drop of 10 psi under PHD conditions is not significant enough to warrant replacing the pipeline segment. If CMWD experiences low-pressure problems in the system in this area under high demand conditions, especially as demands increase as the system is expanded, replacement of this section may assist in resolving low-pressure problems. Also, if one of these pipeline segments should require replacement due to normal maintenance, then the new pipe should be of a larger diameter. The deficiencies identified in Table 8.2 are shown in Table 8.3 along with the pipeline segments, which have less significant effects on the system. Model predictions under AAD conditions are also presented for reference. Table 8.3 Pipeline Deficiencies Under Demand Conditions Recycled Water Master Plan Carlsbad Municipal Water District Map ID Zone Length (ft) Demand Condition Maximum Head Loss Max Velocity (ft/s) Exist Diam (in) Par.(1) Diam (in) Repl.(2) Diam (in) (ft/kft) (ft) A 384 1,100 AAD 5.9 6.3 2.9 1,100 MMD 12.6 13.5 4.4 6 8 12 B 384 1,100 AAD 6.4 5.4 4.7 MMD 11.2 10.9 6.3 12 8 16 C 384 1,300 AAD 8.6 9.5 3.9 MMD 10.5 11.8 4.4 8 8 12 D 384 500 AAD 3.2 1.4 2.5 MMD 8.9 4.1 4.3 8 8 12 E 660 2,200 AAD 2.7 5.2 2.3 MMD 8.1 15.4 4.1 8 8 12 Notes: (1) Parallel (2) Replacement As previously mentioned, since pipeline deficiencies C, D, and E are not located near pressure deficiencies, it is not recommended to replace these pipeline segments. Pipelines A and B contribute, in part, to low pressures in the area. However, the level of head loss associated with pipelines A and B does not warrant replacement at this time. Recommended diameters for any potential replacement or paralleling of pipelines are included in Table 8.3. January 2012 8-9 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 8.doc 8.2 STORAGE CAPACITY ANALYSIS The storage analysis evaluates if CMWD’s existing storage capacity meets the evaluation criteria for operational and emergency as described in Chapter 7. A definition for each category of storage criteria is summarized below. • Operational Storage: The storage required to buffer demand fluctuations under maximum day demand (MDD) conditions. The required operational storage is defined as 33-percent of MDD. • Short-term Emergency Storage: The storage volume required to prevent a reservoir from completely draining during an emergency situation such as a temporary supply outage or a demand spike. The required emergency storage is defined as 17 percent of MDD. For this analysis, it is assumed that MDD conditions will be similar to MMD conditions. The existing system storage facilities are summarized in Table 8.4. Storage for Zones 580 and 318 are provided by reservoir capacity in Zone 384, and storage for Zone 660 and 550 is provided by Mahr Reservoir. It should be noted that the Calavera hydro-pneumatic tank and Bressi hydro-pneumatic tank are not listed in this table, as they are not intended to provide storage. As will be discussed in Section 8.3, Zones 580 and 660 will not have storage if power is not available at the Bressi and Calavera Pump Stations. Table 8.4 Summary of Storage Facilities by Pressure Zone Recycled Water Master Plan Carlsbad Municipal Water District Reservoir Zone Volume (MG) Twin D Tanks 384 2.5 C Tank 384 1.0 Mahr Reservoir 550 32.0(1) Total Storage 35.5 Note: (1) CMWD is only allotted 32 MG of the 50 MG capacity of the Mahr Reservoir. The remaining capacity is allocated to the Olivenhain Municipal Water District. As shown in Table 8.4, CMWD has a total of 35.5 MG of storage. 32 MG of this is associated with Mahr Reservoir, located in Vallecitos Water District’s (VWD) service area. While Mahr Reservoir is used to provide operational and short-term emergency storage for CMWD’s system, CMWD does not typically replenish the reservoir with recycled water from Carlsbad WRF, and Meadowlark WRF is therefore the only source of replenishment for the reservoir. 8-10 January 2012 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 8.doc At this time, daily demands in Zone 550 and 660 are much less than the daily supply from Meadowlark WRF, so CMWD has some flexibility in its use of Mahr Reservoir for operational and short-term emergency storage. As demands increase in Zones 550 and 660, CMWD will be limited in its use of Mahr Reservoir as storage unless CMWD replenishes the reservoir from Carlsbad WRF. Operational and short-term emergency storage requirements that were calculated based on the evaluation criteria discussed above are presented in Table 8.5. This table also shows a comparison of these requirements with the existing storage capacity. It should be noted that storage analysis is not conducted for Gafner WRP since operational storage is provided by the La Costa Golf Course through on- site ponds. Table 8.5 Storage Capacity Evaluation Recycled Water Master Plan Carlsbad Municipal Water District Zone MMD (mgd) Required Operational Storage(1,2) (MG) Required Short-Term Emergency Storage(1,3) (MG) Total Required Storage (MG) Existing Storage (MG) Balance (MG) 660 0.48 0.16 0.08 0.24 0.0(4) -0.24 550 1.06 0.35 0.18 0.53 0.0(4) -0.53 Subtotal 0.51 0.26 0.77 0.0 -0.77 Subtotal w/ Mahr 0.51 0.26 0.77 32.0(4) +31.2 580 0.35 0.12 0.06 0.18 0.0 -0.18 384 3.61 1.19 0.61 1.80 3.5 +1.70 318 0.06 0.02 0.01 0.03 0.0 -0.03 Subtotal 1.23 0.68 2.01 3.5 1.49 Total w/o Mahr 5.56 1.84 0.94 2.78 3.5 +1.49 Total w/ Mahr 5.56 1.84 0.94 2.78 3.5 +32.69 Notes: (1) Operational and Emergency Storage requirements are based on the evaluation criteria from Chapter 7. (2) Based on the evaluation criteria, Operational Storage is 33 percent of the MMD. (3) Based on the evaluation criteria, Emergency Storage is 17 percent of the MMD, or four hours. (4) Supplies from Meadowlark WRF are taken at a constant rate greater than the demand of Zones 550 and 660. Consequently, Operational Storage for Zone 550 is not needed. When necessary, Mahr Reservoir can be used to buffer supplies at Meadowlark WRF. As shown in Table 8.5, there is enough storage to meet operational and short-term emergency demand requirements under existing conditions. In addition, the following conclusions can be made by subarea: • Since supplies from Meadowlark WRF are taken at a constant rate and are greater than the demand of Zones 550 and 660, operational storage is not considered necessary within Zone 550. When necessary, Mahr Reservoir can be used to buffer supplies at Meadowlark WRF. January 2012 8-11 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 8.doc • For Zones 384, 580, and 318, which share common reservoir capacity, the total required operational and emergency storage is 2.01 MG. For Zones 550 and 660, the total required operational and emergency storage is 0.77 MG. 8.3 PUMP STATION CAPACITY ANALYSIS The pump analysis evaluated the adequacy of the existing system pump station capacities. CMWD’s existing recycled water system consists of five pressure zones and associated booster pumping stations. The suction and discharge zones and flow capacities for each pump station are listed in Table 8.6. This table lists both the total capacity for each pump station and the firm capacity, which is the capacity with the largest unit out of service. Note that each of CMWD’s booster pumping stations include a standby pump and consist of pumping units of uniform sizing, so the design capacity is equivalent to the firm capacity. As discussed in Chapter 7, the criteria for each pump station is to meet the PHD with the largest unit out of service. Table 8.6 Booster Pump Station Capacity Evaluation Recycled Water Master Plan Carlsbad Municipal Water District Booster Stations Suction/ Discharge No. of Pumps Total Capacity (gpm) Firm Capacity (gpm) PHD(3) (gpm) Balance (gpm) Bressi PS 550 to 660 2 duty, 1 standby 4,500 3,000 1,015 +1,985 Calavera PS 384 to 580 2 duty, 1 standby 2,700 1,800 724 +1,076 Twin D PS 384 to 550 3 duty, 1 standby 6,000 4,500 1,903 +2,697 Meadowlark WRF PS WRF to 550 2 duty, 1 standby -(2) 3,250 2,083 +1,167 Carlsbad WRF PS WRF to 384 3 duty 10,000 6,667 2,777 +3,890 Notes: (1) TDH: Total Dynamic Head. (2) Total capacity from Meadowlark WRF not reported. Single pump can produce 1,389 gpm and two pumps can product 3,250 gpm. (3) For booster pumping stations, PHD is based on annual downstream demands from Table 2.3, a seasonal peaking factor of 1.7, and a daily peaking factor of 3.0. For treatment facility pump stations, PHD is based on treatment plant capacity from Table 2.1. 8-12 January 2012 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 8.doc As shown in Table 8.6, all pump stations are currently adequately sized and meet the evaluation criteria under existing demand conditions. The Bressi PS and Calavera PS only need to meet existing PHDs of 1,015 and 724 gpm, respectively. They are currently sized for 3,000 and 1,800 gpm. The Twin D Pump Station is capable of transferring all of the flow from the Carlsbad WRF to Zone 550 (approximately 2,700 gpm). Both the Carlsbad WRF PS and the Meadowlark WRF PS are currently sized to deliver peak effluent production from their respective plants. However, it should be noted that the Calavera and Bressi pump stations function as the sole supply to Zones 580 and 660, respectively. As these pump stations do not have backup power and these zones do not have gravity storage it is recommended that backup power be located at each pump station site. To continue service in these pressure zones during a power outage, both pump stations need to be equipped with the appropriate switchgear to connect a portable back-up power generator. It is recommended that CMWD have one portable backup power generator to continue service during minor power outages, provided that Bressi PS and Calavera PS are not connected to the same power grid. It is assumed that interruption of recycled water service would be acceptable during a regional power outage or rolling blackout. 8.4 PUMPING EFFICIENCY AND ENERGY ANALYSIS The energy analysis evaluated each pump station to determine modifications or operational changes that could increase pumping efficiency. The PS examined for possible modifications included: • Twin D PS • Bressi PS • Calavera PS The Meadowlark WRF PS and Carlsbad WRF PS were not evaluated since their operation is dependent on the upstream operation of the treatment facility. In addition, both of these pump stations have either large upstream equalization basin (at Carlsbad WRF) or a large reservoir (Mahr Reservoir) that allows for optimal pumping of plant effluent. For the Twin D PS, it is recommended that CMWD operate the pump station at its peak efficiency operating point, which is possible since excess flow may be deposited into the Mahr Reservoir. For each individual unit, the best efficiency point is at 1,500 gpm and 300 feet Total Dynamic Head (TDH). Under normal operations (when Meadowlark WRF is supplying the system), the Twin D PS is not operated on a regular basis. Thus, average annual energy consumption was not calculated. January 2012 8-13 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 8.doc For the Bressi and Calavera PS, CMWD has recently retrofitted each pump station with a smaller pump capable of more efficiently pumping flow between MinDD and the optimal flow regime of the existing larger pumps. Prior to the retrofit, the Bressi and Calavera PS operated only with upstream hydro-pneumatic tanks. As there is no storage upstream of the Bressi and Calavera PS, the pump station flows must match demand in Zone 580 and Zone 660, respectively. Table 8.7 displays the current demand for each zone and the current efficiency and kilowatts (kWs) required for pumping at the Bressi and Calavera Pump Stations, respectively. Table 8.7 Power Usage for Hydro-pneumatic Zones Recycled Water Master Plan Carlsbad Municipal Water District Booster Stations No. of Pumps Pump Size (gpm) Zone AAD (gpm) Efficiency at AAD(1) Estimated Power Usage at ADD(2) (kW) Bressi PS 2 duty, 1 standby 1,080 199 45% 7.2 Calavera PS 2 duty, 1 standby 620 142 56% 3.5 Notes: (1) Based on pump curves provided by CMWD and assumes VFD turndown of at least 50 percent is achievable. (2) Power usage (kW) estimated based on the pump curves provided by CMWD and ADD. As shown in Table 8.7, there is low efficiency when one of the existing pumps runs to meet the indicated demand. In addition, existing pumps are too large to pump flows much lower than AAD flows without cavitation and backflow that will damage the pumps. A smaller pump at each pump station runs more efficiently than any of the existing pumps when pumping flows below the AAD. The increased efficiency associated with the new smaller pumps both save money and allow the PSs to meet MinDD without damaging the existing pumps. Approximate energy savings are shown in Table 8.8. Table 8.8 Summary of Facilities by Pressure Zone Recycled Water Master Plan Carlsbad Municipal Water District Booster Stations New Efficiency New kW, ADD Existing kW, ADD kW Savings Cost $/kWh Annual Savings(1) Bressi 80% 4.3 7.2 2.9 $0.13 $5,000 Calavera 80% 2.5 3.5 1.0 $0.13 $1,500 Notes: (1) Annual savings rounded to nearest $500. While the annual savings listed in Table 8.8 are not significant, the savings could cover the cost of a small pump, which is needed regardless, since the large pumps are unable to pump MinDD. A smaller pump also reduces wear on the larger pumps due to excessive starting and stopping of the larger pumps. 8-14 January 2012 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 8.doc CMWD has recently retrofitted both the Bressi PS and Calavera PS with smaller pumps capable of both pumping the MinDD and more efficiently pumping flows greater than MinDD, but less than the optimal pumping regime of the existing pumps. This analysis confirms this action. 8.5 WATER QUALITY ANALYSIS The model was used to analyze recycled water quality based on the chlorine residual in the system. The evaluation was used to determine if CMWD should install additional chlorine injection stations to maintain adequate chlorine residuals throughout its distribution system. For this analysis, it was assumed that the chlorine residual of recycled water leaving the treatment plants would be 9.1 mg/L at Carlsbad WRF and 4.5 mg/L at Meadowlark WRF. The chlorine residual at the Carlsbad WRF is based on the average chlorine residual between September 15 and September 30, 2009. The chlorine residual at the Meadowlark Plant is based on the discussion in Chapter 6. In absence of chlorine jar test data, a global bulk chlorine decay coefficient of -0.05 along with a default global wall chlorine decay coefficient of -0.15 were used. These values are consistent with the values used during the calibration. Figure 8.3 displays the chlorine residuals in the system as predicted by the hydraulic model. Under AAD conditions, the major transmission mains in the system (not including small laterals) maintain a chlorine residual above 2.0 mg/L. Also, the C Tank, Twin D Tanks, and Mahr Reservoir all have residuals above 2.0 mg/L under AAD conditions. The chlorine residual for all system reservoir and transmission mains is also above 2.0 mg/L under MMD conditions. However, under MinDD conditions, the model predicts that the chlorine residuals in the C Tank and Mahr Reservoir are 0.02 mg/L and 0.6 mg/L, respectively. The low MinDD creates a low turnover of water in each reservoir, thereby creating a low chlorine residual. For MinDD conditions, many of the transmission mains have a residual below 1 mg/L, especially those mains adjacent to the C Tank. The low residual in the C Tank may be partially due to the limited cycling within the C Tank as its elevation is above the HGL of Zone 384. The higher than expected residual within Mahr Reservoir is likely a limitation of the hydraulic model to adequately predict the increased decay of chlorine residual within a large, open body of water, as the bulk decay rate within Mahr Reservoir is likely higher than that observed in the distribution system pipelines. CMWD could help alleviate the low chlorine residuals under MinDD conditions by installing a chlorination and mixing system in the low residual reservoirs. CMWD recently completed installation of a chlorination and mixing system for Mahr Reservoir in 2008. It is recommended that CMWD considers installing a mixing and chlorination system at the C Tank to maintain the residual during MinDD periods. "C" Tank Carlsbad WRF Gafner WRP Mahr Reservoir Meadowlark WRF Agua HediondaLagoon Twin "D" Tanks E l C a min o R e alElm A veMarron Rd Carlsbad Blvd Hig hlan d D r Alondra W ayPaseo Nort eCollege BlvdPalomar Airport RD Aviara Pkwy Costa Ave P o in s e ttia L nTamarack A veCannon Rd Calle BarcelonaRanc ho Santa FeCalavera PS CWRF PS Bressi PS "D" Tank PSPacific Ocean Encinitas Batiquitos Lagoon Buena VistaLagoon Oceanside Shadowridge WRP OMWDMeter Corintia Meter LakeCalavera J11500.42.32.8 J8740.42.63.2 MWRF4.54.54.5 CWRF9.19.19.1 MAHR0.62.32.6 Four SeasonsResort La Costa Resort Kemper SportsManagement Legoland Aviara ResortAssociation San Marcos Vista Encinitas Oceanside 1200.34.05.4 J4002.33.84.0 J1142.83.94.0 TWIND3.07.47.8 J28161.97.07.5 J21581.02.73.3 J21143.07.17.8 J11821.02.83.3 J861.36.16.5 J4763.67.88.5 J24781.35.36.7 J24062.96.57.3 J19580.82.73.1 J18420.82.63.2 J7020.013.54.8 J4240.041.32.1 CTANK0.024.65.6 0 5,000 10,000Feet Figure 8.3Existing Water System Quality Recycled Water Master PlanCarlsbad Municipal Water DistrictFILENAME: c:\pw_working\projectwise\lwang\d0102644\Figure_8_03-Existing System Water Quality.mxdDATE: 1/14/20110.0 - 1.0 mg/L 1.1 - 2.0 mg/L 2.1 - 4.0 mg/L 4.1 - 6.0 mg/L 6.1 - 9.0 mg/L Water System Facilities Pump Station Pressure Requlating Station (PRS) Meter WRF Tank Reservoir Inactive WRP Other Freeways Local Streets Carlsbad City Limits San Diego County Carlsbad Municipal Water District Boundary Transmission Main Chlorine Residual Legend Average Chlorine Residenals (mg/L) A#.##.##.# MIN DD (mg/L) MMD (mg/L)ADD (mg/L) Model Node ID 8-16 January 2012 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 8.doc This page intentionally left blank. January 2012 8-17 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 8.doc 8.6 OPERATIONS AND MAINTENANCE To keep the existing system operating properly, CMWD may want to start an asset management program for its recycled water system infrastructure. Although these infrastructure assets may function for many years with a relatively small amount of maintenance, these assets will not last forever, and will eventually need to be replaced. The cost of replacing these assets will be very high. CMWD should therefore start with the implementation of an overall asset management program so that the best value possible can be obtained from existing infrastructure and from future infrastructure investments. As an added benefit of developing an asset management program, CMWD could use such a program to estimate the remaining useful life of pipelines within its distribution system. CMWD could then have a basis for establishing an asset renewal fund. Part of this program would involve inspecting facilities every year or two to track the condition of system components. Table 8.9 shows typical frequency of inspection and labor hours for its recycled water facilities. Table 8.9 Facility Inspection Criteria Recycled Water Master Plan Carlsbad Municipal Water District Facility Frequency of Inspection (years) Hours Required Pump Stations 3 - 5 1 - 2 Reservoirs 3 - 5 4 Service Connections 1 - 4 1(1) Large Valve Stations 3 - 5 1 - 2 Pipelines 10 - 12 See Note 2 Notes: (1) Actual test may take up to 24 hours since data is recorded by a pressure logger. Time only accounts for the test preparation. (2) For the suggested frequency, CMWD should conduct a mass balance to isolate areas that may have leaks. If a leak is found from the analysis, field verification and inspection may be required. 8.7 SUMMARY OF RECOMMENDATIONS The existing system was found to have a few hydraulic deficiencies, energy deficiencies, and locations with low chlorine residuals. However, all pump stations are adequately sized and the system has sufficient storage and supplies. Hydraulic deficiencies involved locations with high pressures, locations with low pressures, pipes with high velocities, and pipes with high head loss. Most of the low pressures were due to higher elevations within the existing zones. Most of the high velocity and high head loss pipes were not adjacent or in the vicinity of low pressure nodes, with the exception of two locations. The limited pressure deficiencies caused by these pipelines are not 8-18 January 2012 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 8.doc considered severe enough to warrant replacement at this time. However, CMWD should continue to monitor pressures in the area and, if replacement of these pipeline segments is warranted for other reasons, replace the pipelines with pipelines of a larger capacity. All other low-pressure areas do not represent significant deficiencies or are due to higher elevations within each zone. It is therefore recommended that CMWD continue present operation without changes, in order to avoid the cost of a new pressure zone and new pump station, unless the number of customers served by a new zone and pump station would justify the cost. The model predicts low chlorine residuals in the C Tank during MinDD condition. This low residual is consistent with the residual observed during model calibration. To resolve the deficiencies, the following recommendation was made: • Install a chlorination and mixing system in C Tank to maintain an adequate residual during periods of low demand. The cost for the chlorination and mixing system is included in the capital improvement program discussed in Chapter 10. January 2012 9-1 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Draft Report/Chapter 9.doc Chapter 9 FUTURE SYSTEM EVALUATION 9.1 INTRODUCTION This chapter describes the evaluation of alternatives for expansion of the existing system to maximize service of the potential customers identified in Chapter 3. The evaluation and sizing criteria described in Chapter 7 are used to size these system expansions. This chapter is divided into the following three sections: • Evaluation Methodology. This section discusses the methodology used for the creation of expansion segments, as well as the selection of the recommended recycled water system expansion projects. • Future System Expansion Evaluation. A future recycled water system layout that serves all potential customers was developed and divided into expansion segments. This section presents the pipelines and facilities for each expansion segment, which were sized using the hydraulic model. Planning level cost estimates are also presented for each expansion segment and are prioritized based on unit cost and other considerations. • Future System Recommendations. The expansion segments are compared and a recommended system is selected for the planning horizon of this recycled water master plan (RWMP). In addition, the ultimate system under build-out conditions is described. The Capital Improvement Program (CIP) for the recommended ultimate build-out system is described in Chapter 10 of this RWMP. 9.2 EVALUATION METHODOLOGY For the future system evaluation, the hydraulic model was used to develop potential system expansion alternatives that can serve the projected demands while meeting the supply and evaluation criteria constraints. This section discusses the methodology used for the creation of alternatives and the selection of recommended recycled water system expansion projects. This methodology includes the following steps: • Development of the initial system layout • Division of the initial layout into expansion segments • Evaluation of redundancy alignments and inclusion of abandoned assets • Selection of recommended system The first step in developing a future system is the development of the initial layout of a potential recycled water system. This system would serve the potential customer demands with the potential recycled water supplies as discussed in Chapters 3 and 4, respectively. 9-2 January 2012 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Draft Report/Chapter 9.doc Pipeline alignments were laid out in an attempt to provide service to all potential customers. The pipeline alignments were divided into expansion segments. These expansion segments were refined with input from CMWD staff, who also identified additional pick-up customers where feasible, along the proposed pipeline alignments. Implementation of all expansion segments would maximize the use of recycled water; however, the total cost of a system serving all potential customers is typically relatively high. To make expansion of the recycled water system more cost-effective, the various segments are evaluated based on relative cost expressed in dollars per acre-foot of demand served. The segments are then prioritized based on this unit cost evaluation and incorporated into a phased CIP. 9.3 FUTURE SYSTEM EXPANSION EVALUATION The market assessment conducted in Chapter 3 identified 161 largest customers totaling 5,368 afy (4.8 mgd) as the total potential future system demand in the customer database. This new demand includes 2,711 afy (2.4 mgd) within CMWD’s service area and 2,657 afy (2.4 mgd) in the service areas of neighboring agencies. Expansion segments were developed to maximize the number of customers that could be connected to the recycled water distribution system. However, several customers were determined to be too distant from the recycled water distribution system or isolated such that connection to recycled water would not be viable. To evaluate the cost effectiveness and priority of the various expansion segments, the segments were assigned based on contiguous or nearby potential customers. The potential segments are shown on Figure 9.1. A summary of the potential customer demands by segment is provided in Table 9.1. Some potential customers were not able to be reached by the proposed segments; these are summarized separately in Table 9.1 as “Excluded”. In addition, some potential customers are located adjacent to the existing recycled water distribution system and do not require a new pipeline. These are labeled “Adjacent to Existing”. 9.3.1 Expansion Segments As shown in Table 9.1, the potential demand that can be served if all expansion segments are implemented is estimated to be 4,662 afy (4.2 mgd). This is calculated by deducting 706 afy of demand that was excluded from the customer database demand of 5,368 afy. The potential demand of 4,662 afy (4.2 mgd) includes 3,695 afy (3.3 mgd) of demand associated with conversions of existing potable water customers and 967 afy (0.9 mgd) of demand associated with new customers (not offsetting existing potable water demands). While some new demands may not be in place when Phase III is implemented, it is assumed that all demands will be connected at ultimate build out. For developing unit costs for each alignment, the ultimate average annual demands were used. January 2012 9-3 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Draft Report/Chapter 9.doc Table 9.1 Demands by Expansion Segment Recycled Water Master Plan Carlsbad Municipal Water District Expansion Segment Number of Customers(4) Average Annual Demand (afy) Potable Water Customers New Demands in Customer Database(5) Ultimate System(6) Adjacent to Existing(1) 30 126 472 598 1 19 97 8 105 2 13 782 0 782 3 6 53 280 333 4A(2) 1 448 0 448 4B(2) 9 330 0 330 4C(2) 1 582 0 582 5 16 193 129 322 6 3 20 0 20 7 1 0 64 64 8 2 520 0 520 9 5 65 13 78 10 2 82 0 82 11 16 120 0 120 12 4 41 0 41 13 2 32 0 32 14 2 58 0 58 15 3 22 0 22 16 1 10 0 10 17 6 85 0 85 18 1 31 0 31 Total 143 3,695 967 4,662 Excluded(3) 18 706 0 706 Grand Total 161 4,401 967 5,368 Notes: (1) This category consists of potential customers adjacent to the existing recycled water distribution system that do not require a specific expansion segment and that can directly connect to the system through a customer lateral. This category is assumed to include 30 service laterals. (2) Three segments are included in Segment 4. Each will be discussed in more detail in Section 9.3.1. (3) These demands excluded as the associated potential customers were not able to be efficiently connected to the ultimate recycled water distribution system. (4) The specific expansion segment to which each customer is assigned can be found in Appendix C. Note that the number of customers does not necessarily correspond to the number of service laterals required for retrofit customers. See individual expansion segment descriptions. (5) New Demands are not anticipated to be ready to connect by the time Phase III is completed. (6) Total of Potable Water Customers and New Demands. 9-4 January 2012 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Draft Report/Chapter 9.doc Each of the segments is described briefly below. As shown as the sum of demands in the category “Adjacent to Existing”, the customer database identified 598 afy of potential demand located adjacent to the existing recycled water distribution system, which does not require an expansion of the system. In addition, potential customers representing 706 afy of potential demand (shown as “Excluded” in Table 9.1) were not considered viable for connection to the recycled water distribution system in any of the expansion alternatives due to the remote location of the customers. 9.3.1.1 Expansion Segment 1 Expansion Segment 1 consists of 15,400 feet of pipeline to serve 19 identified customers with an ultimate system demand of 105 afy. This segment would be a part of Zone 550. Expansion Segment 1 is located in the center of CMWD’s service area and consists of connecting customers in the business park surrounding Palomar Airport Road. While Phase II identified several of these customers, some of the expansions were not able to be completed under Phase II. CMWD staff suggested the alignments shown in Expansion Segment 1. CMWD staff estimated that 58 service laterals will be required to connect existing potable customers in this expansion segment. Costs for the laterals have been included in the overall cost for this segment. It should be noted that a number of cooling tower demands totaling an estimated 44 afy have been aggregated into Expansion Segment 1. Due to proximity, many of these demands are for customers that are already on recycled water for irrigation and could be served without any new pipelines. As discussed in Chapter 3, these demands were estimated in aggregate and would require an individual connection to each commercial building as appropriate. 9.3.1.2 Expansion Segment 2 Expansion Segment 2 consists of 17,500 feet of pipeline to serve 13 customers with an ultimate system demand of 782 afy. This segment would be a part of Zone 384 and extend the recycled water system north from Carlsbad WRF along Avenida Encinas to the new power plant and across the lagoon. It is estimated that 18 service laterals will be required to serve existing potable customers in this expansion segment. Although previous recycled water studies have placed this expansion segment in a lower pressure zone, it was decided to raise the hydraulic grade line (HGL) in order to increase looping in Zone 384 and eliminate a pressure reducing station and booster pumping station. Preliminary analysis showed maximum pressure along this alignment as 196 psi at an elevation of 29 ft-msl. Increasing the HGL to Zone 384 will also allow uniform head conditions for all booster pumps at the Carlsbad WRF Pump Station. In addition, this will increase redundancy in the distribution system, as supplies from Carlsbad WRF will be conveyed via transmission mains along Palomar Airport Road and Cannon Road in addition to the transmission main along Poinsettia Lane. "C" Tank Carlsbad WRF Gafner WRP Mahr Reservoir Meadowlark WRF Agua HediondaLagoon Twin "D" Tanks C a min o R e al E lm A veMarron Rd C arls b a d Blv d A londra W ayPaseo Nort eCollege BlvdPalomar Airport Aviara Pkwy El Fuerte StCosta AvePoinsettia LnTam arack A veCannon Rd Calle BarcelonaR ancho Santa FeCalavera PS Bressi PS "D" Tank PS Pacific Ocean Encinitas Batiquitos Lagoon Buena VistaLagoon Oceanside LakeCalavera Corintia Meter OMWDMeter Carlsbad Village Redundancy Pipeline 4B 4C 8 " 6 " Santa Fe I Tank T A P P ip e lin e (n o t in C IP )Pipeline to Santa Fe I Shadowridge WRP San Marcos Vista Encinitas Oceanside 17 4A 8 2 3 6 1 9 11 13 12 10 14 7 15 16 185 C017 C032 C177 C176 C175 C174 C173 C179 C170 C169 C168 C166 C178 C165 C164 C163 C162 C161 C064 C159 C158 C126 C116 C157 C156 C155 C153 C152 C151 C150 C149 C148 C147 C146 C145C144 C143 C102 C123 C103 C112 C101 C105 C111 C114 C136C125 C129 C134 C139C121 C124 C115 C113 C128 C108C130 C127 C118 C122 C131C120 C133 C107 C109C140 C141 C137 C135 C104 C093C099 C100 C005 C009 C001 C061C085 C087 C010 C088 C042 C056 C044 C041 C034 C051 C063 C037 C043 C078 C018 C070 C003 C013 C020 C027 C002 C004 C021 C028 0 5,000 10,000Feet Figure 9.1Potential Expansion SegmentsRecycled Water Master PlanCarlsbad Municipal Water District FILENAME: c:\pw_working\projectwise\lwang\d0102644\Figure_9_1-Expansions Segment by Color.mxdDATE: 4/26/2011Legend Existing Recycled Water Pipelines (by Diameter)Less than 6"6" to 8"10" to 14"16" and largerAlready ConstructedRecycled Water FacilitiesPump StationPRS Meter WRF Tank Reservoir Inactive WRP Customer (by demand in afy)<1010-2525-50 50-100 >100 Other FreewaysRailroadsLocal StreetsWater BodyCarlsbad City LimitsSan Diego CountyCarlsbad Municipal Water District Boundary Potential Expansion Segment Other (Not for Specific Expansion segment) Segment 15Protential Golf CourseCustomer Segment 1 Segment 2 Segment 3 Segment 4A Segment 4B Segment 4C Segment 5 Segment 6 Segment 7 Segment 8 Segment 9 Segment 10 Segment 11 Segment 12 Segment 13 Segment 14 Segment 16 Segment 17 Segment 18 9-6 January 2012 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Draft Report/Chapter 9.doc This page intentionally left blank. January 2012 9-7 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Draft Report/Chapter 9.doc 9.3.1.3 Expansion Segment 3 Expansion Segment 3 consists of 8,600 feet of pipeline to serve 6 customers with an ultimate system demand of 333 afy. Expansion Segment 3 connects several potential developments and existing Home Owner’s Association (HOA) customers along College Blvd and El Camino Real, looping sections of Zone 384 and providing redundancy to the Calavera Pump Station and Zone 384. This alignment includes 280 afy of demand associated with new customers in addition to 53 afy of demand from retrofitting existing potable water customers. Most of this segment would be a part of Zone 384. However, the proposed Holly Springs HOA would require a higher HGL due to its higher elevation. As shown, the alignment includes pipelines to the proposed Holly Springs HOA, extending outside the public right-of-way. However, as development plans become more certain, the alignment can be planned to follow public streets once they have been determined. Service to the Holly Springs HOA will require a booster pumping station due to the elevation difference of about 180 feet. It is anticipated that the developer will provide a small booster pumping station for serving irrigations demands where the pressures fall too low. The associated booster pumping station and distribution pipelines for the Holly Springs HOA, as well as service laterals for all new customers, are assumed to be the responsibility of the developer and are not included in the CIP. Note that the Rancho Carlsbad Executive Golf Course is located near the alignment of this expansion segment, but based on discussions with CMWD staff, it is anticipated that the golf course will be served from Jackspar Drive, making it a part of Expansion Segment 14. 9.3.1.4 Expansion Segment 4 (VID and Oceanside) Expansion Segment 4 is intended to evaluate the potential of serving demands within Vista Irrigation District (VID) and the southeast portion of the City of Oceanside. Three expansion segments were developed for Expansion Segment 4. These are: • Expansion Segment 4A – Wholesale Service to VID at Shadowridge Water Reclamation Plant (WRP) • Expansion Segment 4B – Retail Service to VID and southeast Oceanside customers north of Shadowridge WRP • Expansion Segment 4C – Retail Service to all identified customers within VID south of Shadowridge WRP The alignments of each expansion segment are presented on Figure 9.2, Figure 9.3, and Figure 9.4, while the demand and pipeline lengths are summarized in Table 9.2. As shown in this table, the ultimate system demand of the three expansion segments totals 1,360 afy. "C" Tank El Fuerte StCalavera PS Bressi PS Shadowridge WRP LakeCalavera Failsafe PipelineC A N N O N R D MELROSE DRMELROSE DRS U N S E T D R Connect Failsafe Pipeline to Zone 550 San Marcos Vista COLLEGE BLEL CAMINO REAL C A N N O N R D PAL OMAR AIRPORT RD LAKE BL SHAD OWRIDGE D R C162 C064 C119 C116 C110 C157 C155 C154 C153 C152 C151 C150 C149 C148 C147 C146 C123 C103 C101 C114 C139 C121C117C115 C109 C098 C076 C009 C008 C061 C055 C086 C054 C073 C071 C085 C044 C003 C019 C013 C026 C012 C090 C015C024 C160 C124 C111 C105 C066 C084 Utilize Existing Pipeline from Shadowridge WRP to Golf course. C129 C134 Legend Existing Recycled Water Pipelines (by Diameter)Less than 6"6" to 8"10" to 14"16" and largerExpansion SegmentThis ExpansionOther ExpansionsAlready ConstructedRecycled Water Facilities Pump Station Pressure Regulating Station (PRS) Meter WRF Tank Reservoir Inactive WRP Customer (by demand in afy)<1010-25 25-50 50-100 >100 Served in this Alternative Other FreewaysRailroadsLocal StreetsPotential Golf CoursesWater BodyCarlsbad City LimitsSan Diego CountyCarlsbad Municipal Water District Boundary 0 2,000 4,000Feet Figure 9.2VID Segment 4ARecycled Water Master PlanCarlsbad Municipal Water DistrictFILENAME: c:\pw_working\projectwise\lwang\d0102644\Figure_9_2-VID Alternative 4A.mxdDATE: 1/14/2011 "C" Tank Alondra Way El Fuerte StCalavera PS Bressi PS Oceanside Shadowridge WRP LakeCalavera 8" C A N N O N R D LAKE BL F a ils a fe P ip e lin e MaerkleReservoir MELROSE DRMELROSE DRS U N S E T D R Alternative Service via Tap connection(Requires Sliplining) C139 C111 Connect Failsafe Pipeline to Zone 550 San Marcos Vista5 7 5 7 113 8"8" 8 " 8 "8"8"8"8"8"8"8" 8"8"8"8"8"8"COLLEGE BLEL CA MINO REAL C A N N O N R D PA LOMA R AIRPORT RD MELROSE DR4 8 " S li p lin e 8"12"6 "16"4" 6" 1 2 " 6"12"6" C162 C158 C119C116 C157 C154 C152 C151 C150 C149 C148 C147 C146 C103 C101 C114 C129 C134 C121C117 C124 C115 C109 C009 C044 C003 C013 C026 C012 C090 0 2,000 4,000Feet Figure 9.3VID Segment 4BRecycled Water Master PlanCarlsbad Municipal Water DistrictFILENAME: c:\pw_working\projectwise\lwang\d0102644\Figure_9_3-VID Alternative 4B.mxdDATE: 4/18/2011Served in This Alternative Legend Existing Recycled Water Pipelines (by Diameter) Less than 6" 6" to 8" 10" to 14" 16" and largerProposed Expansion SegmentsThis Expansion Other Expansions TAP ConnectionAlready ConstructedRecycled Water Facilities Pump Station Pressure Regulating Station (PRS) Meter WRF Tank Reservoir Inactive WRP Customer (by demand in afy)<10 10-25 25-50 50-100 >100 OtherFreeways Local StreetsRailroads Potential Golf Courses Water Body Carlsbad City Limits Carlsbad Municipal Water District Boundary "C" Tank College BlvdPalomar Airport Rd El Fuerte StCalavera PS Bressi PS Oceanside Shadowridge WRP LakeCalavera 8" MaerkleReservoir EL Camino Real LAKE BL SHADOWRIDGE DRCANNON R D MELROSE DRS U N S E T D R Connect Failsafe Pipeline to Zone 550 C139 12" Santa Fe I Tank F a ils a fe P ip e lin e San Marcos Vista8"1 2 " 16"4"4" 8 "12"12"6"12"6" 6 " 6"8"6" 6" 6"8"14"12"8"1 2 "6" 4"8"8" 4 "6"4"6"6"6"6"8"8"4"6"6"6"6" 6 "6"6" 4" C032 C119 C116 C157 C155 C154C153 C152 C151 C150 C149 C148 C147 C146 C123 C103 C111 C114 C129 C134 C121C117 C124 C115 C109 C044 C003 C013 C026 C012 C090 Legend Existing Recycled Water Pipelines (by Diameter)Less than 6"6" to 8"10" to 14"16" and largerProposed Expansion SegmentsThis ExpansionOther ExpansionsAlready ConstructedCustomer (by demand in afy)<1010-2525-50 50-100 >100 Water System Facilities Pump Station PressureRegulating Station (PRS) Meter Tank Inactive WRP Parcels Served in This Expansion Segment (C101)OtherFreewaysMajor RoadsRailroadsLocal StreetsPotential Golf CoursesWater BodyCarlsbad City LimitsSan Diego CountyCarlsbad Municipal Water District Boundary 0 2,000 4,000Feet Figure 9.4VID Segment 4CRecycled Water Master PlanCarlsbad Municipal Water District FILENAME: c:\pw_working\projectwise\lwang\d0102644\Figure_9_4-VID Alternative 4C.mxdDATE: 4/18/2011 January 2012 9-11 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Draft Report/Chapter 9.doc Table 9.2 Expansion Segments for Serving Demands in VID (Segment 4) Recycled Water Master Plan Carlsbad Municipal Water District Segment Number of Customers(3) Pipeline Length (ft) Booster Required Ultimate System Demand (afy) Notes 4A 1 700 No 448 Uses Shadowridge WRP for storage 4B 9 23,200 No 330 Includes demand from Segment 4A 4C 369(1) 63,800 Yes(2) 582 Includes demand from Segment 4A and 4B Total 379 87,700 1,360 Notes: (1) While listed as one entry in the customer database, the large business park southeast of Shadowridge WRP served by Expansion Segment 4C actually represents a large number of potential landscape irrigation demands. Considered individually, these demands are quite small. However, CMWD has converted a large number of similar landscape irrigation demands in its own business parks. (2) A booster station would be required to serve customers connected to segment 4C from the failsafe pipeline. However, Bressi PS could be used to serve these customers directly from CMWD’s existing Zone 660. (3) Specific customers served by each segment are shown on Figure 9.2, Figure 9.3, and Figure 9.4. Number of customers for Segment 4C is approximated based on the number of parcels. A list of customers included in each alternative is shown in Table 9.3. Preliminary hydraulic analysis using the hydraulic model shows that the HGL of Zone 550 will convey sufficient pressure to directly drive flow through the failsafe pipeline. It is assumed that sufficient operational storage is available at Shadowridge WRP to buffer the difference between supply via the failsafe pipeline and recycled water demands over the course of the day. However, with a ground elevation approximately 440 ft-msl at the Shadowridge WRF, if existing storage capacity at Shadowridge WRP is used, a pump station would be required to serve potential customers at an HGL of 550 ft-msl. Expansion Segment 4A, depicted in Figure 9.2, consists of providing recycled water to Shadowridge WRP through the existing failsafe pipeline to supply only the demands associated with the Shadowridge Golf Course. Expansion Segment 4B, depicted in Figure 9.3, consists of supplying all identified VID and City of Oceanside (COO) customers that could be supplied at a HGL of 550 ft-msl. Again, recycled water is provided to Shadowridge WRP through the existing failsafe pipeline. Recycled water is then supplied to customers through a distribution system from Shadowridge WRP. Expansion Segment 4C would serve irrigation demands in the large business park to the southeast of Shadowridge WRP. The increased elevation of the business park will require an HGL of about 660 ft-msl. Based on a PHD of 1,840 gpm and a pumping head of 9-12 January 2012 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Draft Report/Chapter 9.doc 133 feet, this could be accomplished through a booster pumping station sized at about 90 hp, or by using the existing capacity of the Bressi PS. Table 9.3 Customer Demands in Expansion Segment 4 Alternatives Recycled Water Master Plan Carlsbad Municipal Water District Customer ID Customer Name Existing Purveyor Ultimate System Demand (afy) Expansion Segment C003 Shadowridge Golf Course VID 448 4A C103 Ocean Hills Country Club COO 148 4B C111 Buena Vista Park VID 54 4B C114 Rancho Buena Vista High VID 39 4B C117 Madison Middle/Lake Elementary COO 34 4B C121 Lake Park COO 22 4B C124 New Venture Christian Schools COO 13 4B C129 Breeze Hill Park VID 11 4B C134 Breeze Hill Elementary VID 8 4B C139 Montessori of Oceanside COO 1 4B C101 Business Park VID 582 4C It should be noted that demands for the business park (Customer ID C101) were estimated based on typical water demand factors calculated from existing recycled water demands for business parks in CMWD’s service area. The business park was not included in VID’s identified potential customers. Since providing recycled water to the business park would include a number of retrofit connections, costs for service laterals were included based on the number of parcels in the business park. A total of 369 service laterals are included in the cost for this expansion segment. 9.3.1.5 Expansion Segment 5 Expansion Segment 5 consists of 54,200 feet of pipeline to serve 16 customers with an ultimate system demand of 322 afy. This segment would be a part of Zone 384, extending the recycled water distribution system north along El Camino Real to serve the second phase of Robertson’s Ranch, several existing HOAs, and existing landscape irrigation. 9.3.1.6 Expansion Segment 6 Expansion Segment 6 consists of 3,900 feet of pipeline to serve 3 customers with an ultimate system demand of 20 afy. The La Costa Ridge HOA is currently served recycled water by a private pump station and existing pipeline near Meadowlark WRF. It is anticipated that CMWD will take over operation of the pump station and pipeline. Expansion Segment 6 would build upon this existing pipeline, extending it to serve 3 additional customers near the La Costa Ridge HOA. Costs are not anticipated or included for January 2012 9-13 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Draft Report/Chapter 9.doc incorporating the existing private pump station and pipeline into CMWD’s system; rather the costs for Expansion Segment 6 consist solely of new pipeline to reach the 3 additional customers. Note that the capacity of the existing pump station was not evaluated; it was assumed that the pump station would have sufficient spare capacity to accommodate the additional demands. 9.3.1.7 Expansion Segment 7 Expansion Segment 7 consists of 2,500 feet of pipeline to serve 1 customer with an ultimate system demand of 64 afy. Expansion Segment 7 provides service to the Quarry Creek development from Zone 580. Based on an estimated elevation of 117 ft-msl, static pressures could exceed 200 psi. Thus, a pressure regulator may be required. However, it is anticipated that this would be constructed on site and paid for by the developer. Based on input from CMWD staff, it is anticipated that the alignment along Tamarack Avenue and down the hillside, crossing approximately 300 feet of HOA property outside the public right of way, is preferable to the alignment along Milford Place or College Boulevard and Marron Road, portions of which would extend outside CMWD’s service area. 9.3.1.8 Expansion Segment 8 (OMWD and La Costa Resort and Spa) Expansion Segment 8 consists of 6,500 feet of pipeline to serve La Costa Resort and Spa and OMWD’s demands lower zone demand with an ultimate system demand of 520 afy. This segment would be a part of Zone 384. Expansion Segment 8 consists of a pipeline along El Camino Real, connecting CMWD’s recycled water system to OMWD and existing landscape irrigation at La Costa Resort and Spa. The feasibility of developing this alternative depends greatly on the timing of recycled water needs from OMWD. Alternatively, this alignment could also be used to connect LWWD’s (Leucadia Wastewater District) currently isolated Gafner WRP distribution system to CMWD’s extensive recycled water distribution system, assuming appropriately sized pumps would be installed at Gafner WRP to deliver flows to Zone 384. Based on alternative 4 supply recommendation in Chapter 4, Gafner would not be utilized as a supply source. If another supply alternative from Chapter 4 is used, use of Gafner may be beneficial to CMWD. 9.3.1.9 Expansion Segment 9 Expansion Segment 9 consists of 5,800 feet of pipeline to serve 5 customers with an ultimate system demand of 78 afy. This segment would be a part of Zone 318, expanding the recycled water system south to the San Pacifico HOA and various existing landscape irrigation and potential development. A portion of this alignment extends Zone 318 south along Avenida Encinas to the Poinsettia Village shopping center and the Lake Shore Garden mobile home park. 9-14 January 2012 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Draft Report/Chapter 9.doc 9.3.1.10 Expansion Segment 10 (VWD) Expansion Segment 10 consists of 3,400 feet of pipeline to serve 2 customers with an ultimate system demand of 82 afy. This segment would be a part of Zone 550 and would serve the commercial development in Vallecitos Water District’s (VWD) service area near Meadowlark WRF. It is anticipated that the south leg of this alignment could be connected directly to VWD’s pipeline (upstream from CMWD’s meter). 9.3.1.11 Expansion Segment 11 Expansion Segment 11 consists of 25,700 feet of pipeline to serve 16 customers with an ultimate system demand of 120 afy. This segment would be a part of Zone 384, extending Expansion Segment 2 north to the Carlsbad Village, serving existing parks, schools, and landscape irrigation demands in the Carlsbad Village area. The proposed alignment crosses Interstate 5 at Chestnut Avenue, extending north along the freeway to Holiday Park, the civic center, and Buena Vista school. This expansion segment will require either Expansion Segment 2 or Expansion Segments 5 and 12 (with the loop connection along Chestnut Avenue). 9.3.1.12 Expansion Segment 12 Expansion Segment 12 consists of 8,100 feet of pipeline to serve 4 customers (representing 14 meters) with an ultimate system demand of 41 afy. This segment would be a part of Zone 384. Expansion Segment 12 extends Expansion Segment 11 north from Carlsbad Village to several schools. Pressures for customers at the highest elevation portions of this expansion segment are predicted by the hydraulic model to be at a minimum of 85 psi. This alignment is dependent on Expansion Segment 2 and Expansion Segment 11 or Expansion Segment 5 with the loop connection along Chestnut Avenue. 9.3.1.13 Expansion Segment 13 Expansion Segment 13 consists of 5,900 feet of pipeline to serve 2 customers with an ultimate system demand of 32 afy. This segment would be a part of Zone 384, serving customers along Paseo Del Norte and Car Country Drive, connecting the Zone 384 pipelines along Cannon Road and Palomar Airport Road. 9.3.1.14 Expansion Segment 14 Expansion Segment 14 consists of 5,900 feet of pipeline to serve 2 customers with an ultimate system demand of 58 afy. This segment would be a part of Zone 384 and would connect the Carlsbad Canterbury HOA and Rancho Carlsbad Executive Golf Course to the existing recycled water distribution system, connecting some existing recycled water pipeline segments currently conveying potable water along Jackspar Drive and Frost January 2012 9-15 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Draft Report/Chapter 9.doc Avenue. After development of Expansion Segment 3, this Expansion Segment will connect the Zone 384 pipeline in Cannon Road with the Zone 384 pipeline in College Boulevard. Note that the Rancho Carlsbad Golf Course could be served from Expansion Segment 3; but based on discussions with CMWD staff, it is anticipated that the golf course will be connected from Jackspar Drive rather than along El Camino Real. 9.3.1.15 Expansion Segment 15 Expansion Segment 15 consists of 2,300 feet of pipeline to serve a total of 9 meters for 4 HOAs (listed as 3 customers in the customer database) with an ultimate system demand of 22 afy. This segment would be a part of Zone 384, connecting the Viaggio HOA, Aviara Masters HOA, and Marea to the existing recycled water distribution system. A second leg of this alignment connects the Tramonto HOA to the existing recycled water distribution system and can connect to a potential HOA development south of Hummingbird Road. 9.3.1.16 Expansion Segment 16 Expansion Segment 16 consists of 1,400 feet of pipeline to serve 3 meters for the Pavoreal HOA with an ultimate system demand of 10 afy. This segment would be a part of Zone 384, connecting the Pavoreal HOA to the existing recycled water distribution system. 9.3.1.17 Expansion Segment 17 Expansion Segment 17 consists of 19,000 feet of pipeline to serve 6 customers with an ultimate system demand of 85 afy. This segment would be a part of Zone 384, connecting the HOAs north of La Costa Resort to the existing recycled water system. This alignment connects the Greenview HOA, Alga Hills HOA, Jockey Club HOA, Alicante Hills HOA, and the Fairways HOA to the existing recycled water distribution system. 9.3.1.18 Expansion Segment 18 Expansion Segment 18 consists of 5,400 feet of pipeline to serve 17 existing meters (listed in the customer database as an aggregate of several customers in an area) with an ultimate system demand of 31 afy. This segment would be a part of Zone 550, connecting several existing commercial irrigation demands north of Faraday Avenue to the existing recycled water distribution system. 9.3.2 Other System Expansion Pipelines In addition to the 18 expansion segments developed to connect potential customers, three expansion segments were developed for other reasons, including looping, connection to storage, and increasing redundancy in the system. While cost evaluations for each of these segments will be presented later in this chapter, a short description of each expansion segment is provided here. Note that since the purpose of these segments is not to connect potential customers, they will not be included in the expansion segment unit cost 9-16 January 2012 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Draft Report/Chapter 9.doc development in Section 9.3.3, but cost estimates for each will be discussed later in this chapter. 9.3.2.1 Redundancy Pipeline for Carlsbad Village This pipeline would connect Expansion Segment 12 and Expansion Segment 5 to provide a second supply of recycled water to the Carlsbad Village. This pipeline would consist of 4,200 feet of pipeline. Since Expansion Segments 5 and 12 are both a part of Zone 384, no pressure regulating or booster pumping stations are anticipated to be required. This pipeline would also serve as an alternate way to connect Expansion Segment 12 if Expansion Segment 11 or 2 are not constructed. 9.3.2.2 TAP Pipeline The Tri-Agency Pipeline (TAP) pipeline consists of a 20-inch diameter pipeline just under 2 miles in length from College Boulevard to Cannon Road across the undeveloped area south of Lake Calavera. The pipeline was a part of the potable water system and is no longer necessary. This pipeline could be used as an alternative to repurposing the failsafe pipeline in Expansion Segment 4 and could serve City of Oceanside demands in Expansion Segment 4B without using the failsafe pipeline. An evaluation of the costs for sliplining the TAP pipeline as an alternative to using the failsafe pipeline is included in Section 9.3.9.2. 9.3.2.3 Pipeline to Santa Fe I The Santa Fe I tank is a 2.5 MG abandoned potable reservoir at an elevation suitable as gravity storage for Zone 660. While the tank is connected to an abandoned pipeline along Palomar Airport Road, portions of the pipeline have been destroyed. An alternate alignment over a shorter distance of 4,200 feet from the north would connect the tank to pipelines proposed as a part of Expansion Segment 4C. The rehabilitated Santa Fe I tank could then provide gravity storage for CMWD’s existing Zone 660 as well as customers connected by Expansion Segment 4C. Further discussion of this pipeline is included in the storage analysis in Section 9.3.11. 9.3.2.4 Pipelines to Potential Developments In addition to the potential customers identified in the customer database that would be served with the expansion segments discussed above, there were additional demands identified in Chapter 3 that are associated with new developments. Pipelines extending to these developments are included as a separate category due to the indefinite timing of these developments. The demands and pipelines associated with serving these developments were included in the hydraulic model in order to adequately size the system for build-out demand conditions. However, unit costs were not developed for it. Development pipelines are shown on the build-out map for reference, though it is anticipated that more detailed routing and sizing of January 2012 9-17 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Draft Report/Chapter 9.doc these pipelines should be developed as more details on the developments are made available. 9.3.3 Alternatives Sizing and Cost Estimates A pipeline diameter of 8 inches was initially used for all looped pipeline segments. Smaller diameter pipelines were used for dead end pipelines as discussed in the evaluation criteria established in Chapter 7. Where found to be deficient using the hydraulic model, pipeline diameters were increased based on the velocity and head loss criteria specified in Chapter 7. Where pressures fell below the evaluation criteria of 60 psi, booster stations were added to specific expansion segments (as noted previously in Section 9.3.1). The length of pipeline for each alternative and associated preliminary cost estimate is summarized in Table 9.4. The alignment demands and unit costs presented in Table 9.4 are shown graphically in Figure 9.5 along with the cumulative demand contributed by each expansion segment. Detailed information on the unit cost development and cost estimate assumptions are included in Chapter 10. Preliminary conveyance cost estimates are shown here to aid in prioritization of potential expansion segments. 0 500 1,000 1,500 2,000 2,500 3,000 3,500 4,000 4,500 5,000 $0 $500 $1,000 $1,500 $2,000 $2,500 $3,000 $3,500 $4,000 $4,500 $5,000 0 1 2 3 4A 4B 4C 5 6 7 8 9 10 11 12 13 14 15 16 17 18 Cumulative Additional Demand (afy)Conveyance Unit Cost ($/acre-ft)Conveyance Unit Cost ($/af)Cumulative Demand (afy) Figure 9.5 Expansion Segment Unit Costs 9-18 January 2012 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Draft Report/Chapter 9.doc As shown in Figure 9.5, the estimated conveyance unit costs range significantly from less than $100/acre-foot to over $2,500/acre-foot. Note that the other system expansion pipelines discussed in Section 9.3.2 are not included since their primary purpose is not to connect potential customers. Table 9.4 Expansion Segments Preliminary Cost Estimates Recycled Water Master Plan Carlsbad Municipal Water District Expansion Segment Potential Demand (afy) Pipeline Length (ft) Capital Cost(2) Annual Cost(3) Unit Conveyance Cost ($/af) 0 598 - $185,000 $12,000 $20 1 105 15,400 $3,025,000 $192,000 $1,833 2 782 17,500 $7,700,000 $489,000 $626 3 333 8,600 $1,755,000 $111,500 $335 4A 448 700 $485,000 $31,000 $69 4B 330 23,200 $5,220,000 $331,500 $1,005 4C 582 63,800 $14,820,000 $940,500 $1,615 5 322 54,200 $9,995,000 $634,500 $1,969 6 20 3,900 $725,000 $46,000 $2,330 7 64 2,500 $540,000 $34,500 $535 8 520 6,500 $1,505,000 $95,500 $184 9 78 5,800 $1,090,000 $69,500 $894 10 82 3,400 $650,000 $41,500 $504 11 120 25,700 $4,955,000 $314,500 $2,614 12 41 8,100 $1,545,000 $98,500 $2,391 13 32 5,900 $1,145,000 $73,000 $2,303 14 58 5,900 $1,070,000 $68,000 $1,166 15 22 2,300 $445,000 $28,500 $1,319 16 10 1,400 $265,000 $17,000 $1,753 17 85 19,000 $3,410,000 $216,500 $2,558 18 31 5,400 $1,125,000 $71,500 $2,306 Total(4) 4,662 279,200 $61,495,000 $3,906,500 n/a Notes: (1) Includes costs for pipelines as well as pressure regulating stations and booster pumping stations as required. These additional facilities are discussed in Section 9.3.1. (2) Capital Cost includes a construction cost contingency of 20 percent and additional markups for engineering and legal costs of 27.5 percent. Cost estimates and cost assumptions are discussed in detail in Chapter 9. (3) Annual cost assumes a useful life of 50 years and 6.0 percent interest. (4) Excludes Expansion Segment 19 and thus differs from Table 9.1 total by 4 afy. January 2012 9-19 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Draft Report/Chapter 9.doc 9.3.4 Alternatives Ranking and Prioritization The expansion segments presented in Section 9.3.1 were prioritized based on unit conveyance cost estimates presented in Table 9.4. The resulting ranking is presented in Table 9.5 and graphically shown in Figure 9.6. This figure also shows the cumulative demand added to the existing system if all expansion segments were constructed in the order of increasing unit cost. The total cumulative demand listed in Table 9.5 includes CMWD’s existing and near-term demands as well as all potential demands discussed in Chapter 3. Table 9.5 Expansion Segments Ranking Recycled Water Master Plan Carlsbad Municipal Water District Rank Expansion Segment Pipeline Length (ft) Capital Cost(1) Alignment Unit Cost ($/af) Cumulative Potential Demand (afy) Total Cumulative Demand (afy)(2) 0 0 - $185,000 $20 598 4,215 1 4A 700 $485,000 $69 1,046 4,663 2 8 6,500 $1,505,000 $184 1,566 5,183 3 3 8,600 $1,755,000 $335 1,898 5,515 4 7 2,500 $460,000 $458 1,963 5,580 5 10 3,400 $650,000 $504 2,045 5,662 6 2 17,500 $7,700,000 $626 2,827 6,444 7 9 5,800 $1,090,000 $894 2,904 6,521 8 4B 23,200 $5,220,000 $1,005 3,234 6,851 9 14 5,900 $1,070,000 $1,166 3,293 6,910 10 15 2,300 $445,000 $1,319 3,314 6,931 11 4C 63,800 $14,820,000 $1,615 3,896 7,513 12 16 1,400 $265,000 $1,753 3,906 7,523 13 1 15,400 $3,025,000 $1,833 4,011 7,628 14 5 54,200 $9,995,000 $1,969 4,333 7,950 15 18 5,400 $1,045,000 $2,145 4,364 7,981 16 13 5,900 $1,145,000 $2,303 4,396 8,013 17 6 3,900 $725,000 $2,330 4,416 8,033 18 12(3) 8,100 $1,545,000 $2,391 4,457 8,074 19 17 19,000 $3,410,000 $2,558 4,541 8,158 20 11(3) 25,700 $4,955,000 $2,614 4,662 8,279 Total(4) 279,200 $61,495,000 4,662 8,279 Notes: (1) Cost estimates and cost assumptions are discussed in detail in Chapter 9. (2) Includes existing plus near-term demand of 3,617 afy (based on reduced 2010 demands). (3) Expansion Segment 12 requires implementation of Expansion Segment 11, which requires Expansion Segment 2. (4) Excludes Expansion Segment 19 and thus differs from Table 9.1 total by 4 afy. 9-20 January 2012 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Draft Report/Chapter 9.doc As shown in Table 9.5, if all expansion segments are implemented, approximately 4,662 afy of demand would be added to CMWD’s system at a total capital cost of about $61 million for distribution system components. This equates to an average unit capital distribution system cost of $837 per acre-foot. 0 500 1,000 1,500 2,000 2,500 3,000 3,500 4,000 4,500 5,000 $0 $500 $1,000 $1,500 $2,000 $2,500 $3,000 $3,500 $4,000 $4,500 $5,000 0 4A 8 3 7 10 2 9 4B 14 15 4C 16 1 5 18 13 6 12 17 11 Cumulative Demand (afy)Conveyance Unit Cost ($/acre-ft)Phase III Expansion Segments Build-out Expansion Segments Cumulative Potential Demand (afy) Note: Conveyance costs do not include treatment costs. Figure 9.6 Expansion Segment Unit Costs As shown in Figure 9.6 the incremental new demand decreases after implementation of Expansion Segment 4C, while the unit cost for conveyance continues to increase. Since implementation of Expansion Segment 4C will require significant inter-agency coordination and because this segment marks the point where the unit conveyance cost exceeds $1,500/acre-foot, it was decided to define all segments up through Expansion Segment 15 as Phase III and categorize the remaining segments for the Build Out. Details regarding Phase III and the Build Out Phase are discussed in more detail below. 9.3.5 Preferred Alternative - Phase III As shown in Table 9.5 and Figure 9.6, the unit conveyance costs (not including treatment costs) for expansion segments after Expansion Segment 15 exceed $1,500 per acre-foot. If all expansion segments below $1,500 per acre-foot are included in Phase III, this Phase will January 2012 9-21 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Draft Report/Chapter 9.doc capture approximately 71 percent of the remaining potential demand. A summary of the demands and costs of the Phase III expansion segments is presented in Table 9.6. Table 9.6 Preferred Alternative – Phase III Recycled Water Master Plan Carlsbad Municipal Water District Expansion Segment Retrofit AAD(1) (afy) Ultimate AAD(1) (afy) Pipeline Length (ft) Capital Cost(2,3) Alignment Unit Cost(4) ($/af) 0 126 598 - $185,000 $20 4A(5) 448 448 700 $485,000 $69 8 520 520 6,500 $1,505,000 $184 3 53 333 8,600 $1,755,000 $335 7 0 64 2,500 $460,000 $458 10 82 82 3,400 $650,000 $504 2 782 782 17,500 $7,700,000 $626 4B 330 330 23,200 $5,220,000 $1,005 9 65 78 5,800 $1,090,000 $894 14 58 58 5,900 $1,070,000 $1,166 15 22 22 2,300 $445,000 $1,319 Total 2,485 3,314 76,400 20,565,000 $378(6) Notes: (1) Phase III AAD includes temporary agricultural demands but excludes development demands, which are not anticipated to be fully in place by the time Phase III is constructed. Ultimate AAD includes development demands, but excludes agricultural demands, which will be replaced by development. (2) Includes costs for pipelines as well as pressure regulating stations and booster pumping stations as required. These additional facilities are discussed in Section 9.3.1. (3) Capital Costs include a construction cost contingency of 20 percent and additional markups for engineering and legal costs of 27.5 percent. Cost estimates and cost assumptions are discussed in detail in Chapter 10. (4) Unit cost assumes a useful life of 50 years and 6.0 percent interest. (5) Pipeline lengths for Expansion Alternative 4A are not anticipated to be significant due to the utilization of the existing unused failsafe pipeline from Shadowridge. (6) Overall unit cost for all expansion segments listed as a part of Phase III. As shown in Table 9.6, it is estimated that Phase III demand of the segments listed in this table will add approximately 3,314 afy of new demand to CMWD’s existing recycled water system for a distribution system capital cost of about $20 million. It is anticipated that the implementation of Phase III will take approximately 10 years, five years for building the infrastructure to support Phase III and five years to connect the customers. The combined unit cost of the expansion segments of Phase III without treatment is estimated at $394 per acre-foot. The total Phase III demand with the existing and near-term demand of 4,100 afy is estimated to reach about 7,414 afy. 9-22 January 2012 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Draft Report/Chapter 9.doc 9.3.6 Preferred Alternative - Build Out The remaining expansion segments are included in the Build-Out Phase. Expansion segments recommended for potential incorporation into the Build-Out Phase are listed in Table 9.7. Table 9.7 Preferred Alternative – Build-out Phase Recycled Water Master Plan Carlsbad Municipal Water District Expansion Segment Ultimate System Demand (afy) Pipeline Length (ft) Capital Cost(1,2) Alignment Unit Cost(3) ($/af) 4C 582 63,800 $14,820,000 $1,615 16 10 1,400 $265,000 $1,753 1 105 15,400 $3,025,000 $1,833 5 322 54,200 $9,995,000 $1,969 13 32 5,900 $1,145,000 $2,303 18 31 5,400 $1,045,000 $2,145 6 20 3,900 $725,000 $2,330 12(2) 41 8,100 $1,545,000 $2,391 17 85 19,000 $3,410,000 $2,558 11 120 25,700 $4,955,000 $2,614 Total 1,348 202,800 $40,930,000 $1,927(4) Development of Vacant Land 344 Total with Vacant Land Development 1,692 Notes: (1) Includes costs for pipelines as well as pressure regulating stations and booster pumping stations as required. Such additional facilities are discussed in Section 9.3.1. (2) Capital Costs include a construction cost contingency of 20 percent and additional markups for engineering and legal costs of 27.5 percent. Cost estimates and cost assumptions are discussed in detail in Chapter 9. (3) Unit cost assumes a useful life of 50 years and 6.0 percent interest. (4) Overall unit cost for all expansion segments. As shown in Table 9.7, it is anticipated that the segments included in the Build Out Phase will connect about 1,348 afy of potential customer demands for a distribution system capital cost of nearly $41 million. The overall unit conveyance cost of these expansion segments is $1,927 per acre-foot. The appropriate timing on incorporating these more costly system expansions will greatly depend on the future development of potable water cost, availability, and reliability. CMWD should continue monitoring development plans near these expansion segments, as additional potential demands may make these expansion segments more economically viable. January 2012 9-23 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Draft Report/Chapter 9.doc CMWD’s service area also includes potential areas of new development for which there is limited information on timing as discussed in Section 3.5.8. Demands for these areas were estimated at 344 afy. The demand for these potential areas of new development was included in the sizing of pipelines and future treatment plant expansions. However, the conveyance cost for serving these vacant areas are not included in the CIP as the onsite development piping is typically paid for by the developers. The alignments shown on the maps may not follow the layout of the eventual tracts and are only intended to show the potential location of developments. The proposed build out system by pressure zone along with the locations of booster pumping stations and pressure regulating stations is shown on Figure 9.7. 9.3.7 Summary of Demand Projections Based on the phasing of expansion segments discussed previously, the water demands for each phase were estimated as shown in Table 9.8. This table summarizes the projected demands under average annual, average day, and maximum month conditions for each phase. Table 9.8 Summary of Demands by Phase Recycled Water Master Plan Carlsbad Municipal Water District Phase Ultimate System Demand (afy) Average Day Demand (mgd) Maximum Month Demand(2) (mgd) Existing + Near Term 4,100 3.7 6.3 Phase III Expansion Segments(1) 3,314 2.9 4.7 Phase III Subtotal 3,314 2.9 4.7 Phase III Total 7,414 6.6 11.0 Build Out Expansion Segments 1,348 1.2 2.0 Development of Vacant Land 344 0.3 0.5 Build-Out Phase Subtotal 1,692 1.5 2.5 Ultimate System Total 9,106 8.1 13.5 Notes: (1) Assumes that all potential customers adjacent to the existing system are connected during Phase III (2) MMD peaking factors vary by customer (see Appendix C for details). As shown in Table 9.8, a total of 9,106 afy of demand was identified as the ultimate system demand. It is estimated that the total Phase III demand would be approximately 7,414 afy. In addition to a breakdown by phase, demands are presented by service area in relative to CMWD’s service area boundary (inside versus outside) in Table 9.9. 9-24 January 2012 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Draft Report/Chapter 9.doc Table 9.9 Potential Demand Outside CMWD’s Service Areas Recycled Water Master Plan Carlsbad Municipal Water District Phase Demand by Agency (afy) CMWD VID Oceanside VWD OMWD Total Existing 4,100 0 0 0 0 4,100 Phase III 1,954 560 218 82 500 3,314 Build-out 746 582 - 20 - 1,348 New Development 344 0 - - - 344 Total Ultimate 7,143 1,142 218 102 500 9,106 Not Feasible 11 16 37 455 187 706 Total Potential 7,155 1,158 255 557 687 9,812 As shown in Table 9.9, the new Phase III demand associated with customers inside CMWD’s service area is 1,954 afy (59 percent) of the total Phase III demand, while the remaining 1,360 afy (41 percent) is located in the service areas of neighboring agencies. During the Build-Out Phase, it is estimated that CMWD could serve an additional 746 afy while about half of the demand in this phase (602 afy) is located outside CMWD’s service area. This means that under Ultimate System Conditions, approximately 27 percent of the total build out demand of 9,106 afy would be served to customers outside CMWD’s service area. 9.3.8 Supply Strategy As discussed in Chapter 4, the recommended supply alternative consists of the expansion of Carlsbad WRF, abandoning Gafner WRP, and continued utilization of Meadowlark WRF. The recommended supply strategy is to utilize Meadowlark WRF as CMWD’s baseline supply and Carlsbad WRF as CMWD’s peaking supply while incorporating seasonal storage as possible. Figure 9.8 and Figure 9.9 show how this supply strategy would meet the seasonal variation of demand on a monthly basis under Phase III and Ultimate demand conditions, respectively. "C" Tank Carlsbad WRF Gafner WRP Mahr Reservoir Meadowlark WRF Agua HediondaLagoon Twin "D" TanksCam i n o R e a l Elm Ave Marron Rd C a r l s b a d B l v d Hi g h l a n d D r Paseo No rte College BlvdPalomar Airport RD Aviara Pkwy El Fuerte StCosta AvePoinsettia LnTamarack Ave Cannon Rd Calle B a r c e l o n a Rancho Santa FeCalavera PS Bressi PS "D" Tank PSPacific Ocean Encinitas Batiquitos Lagoon Buena VistaLagoon Oceanside Shadowridge WRP LakeCalavera Corintia Meter OMWDMeter 8" Santa Fe Tank I MaerkleReservoir TAP Pipeline (not in CIP) San Marcos Vista Encinitas Oceanside C017 C032 C177 C176C175 C174 C173 C172 C179 C170 C169 C168 C166 C178 C165 C164 C163 C162 C161 C064 C159 C158 C126 C119C116 C157 C156 C155 C153 C152 C151 C149 C148 C147 C146 C145 C144 C143 C102 C123 C103 C112 C101 C105 C111 C114 C136C125 C129 C134 C139C121 C124 C115 C113 C128 C108C130 C127 C118 C122 C131C120 C133 C107 C109C140 C141 C137 C135 C104 C093C099 C100 C005 C009 C001 C059 C050 C053 C061C065C071 C087 C010 C088 C042 C056 C044 C041 C034 C051 C063 C037 C043 C078 C018 C070 C045 C014C038 C003 C013 C020 C027 C026 C002 C004 C012 C021 C028 C102 C105 C115 C108 C118 C120 LegendExisting Recycled Water Pipelines (by Pressure Zone)318384550580660Potential Expansion Segments (by Pressure Zone)318384550580660Recycled Water Facilities Pump StationPRS Meter WRF Tank Reservoir Rehabilitate Abandoned Tank Inactive WRPCustomer (by demand in afy)<1010-2525-50 50-100 >100 Proposed Facilities New PRS/Valve OtherFreewaysRailroadLocal StreetsFailsafe PipelineCarlsbad Municipal Water District BoundaryWater BodyCarlsbad City LimitsSan Diego County 0 5,000 10,000Feet Figure 9.7Build Out System by Pressure ZonesRecycled Water Master PlanCarlsbad Municipal Water DistrictFILENAME: C:\pw_working\projectwise\jdmeyerhofer\d0102644Figure_9_7-Proposed Presure Zone.mxdDATE: 1/17/2012Not Feasible Indicated by Grey 9-26 January 2012 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Draft Report/Chapter 9.doc This page intentionally left blank. January 2012 9-27 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Draft Report/Chapter 9.doc Figure 9.8 Phase III Supply Strategy Figure 9.9 Build Out Supply Strategy 2.0 2.0 2.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 2.0 0.9 0.8 1.2 4.0 4.0 4.0 4.0 4.0 4.0 4.0 4.0 2.4 0.2 2.3 4.2 5.8 6.4 4.9 4.1 0.2 0 2 4 6 8 10 12 14 16 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Average Daily Demand During Month (mgd) Meadowlark WRF Carlsbad WRF Carlsbad WRF Expansion Average Daily Demand During Month (mgd) 2.0 2.0 2.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 2.0 0.4 0.3 0.6 2.9 4.0 4.0 4.0 4.0 4.0 4.0 2.9 0.0 0.6 2.1 3.5 4.0 2.7 2.0 0 2 4 6 8 10 12 14 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Average Daily Demand During Month (mgd) Meadowlark WRF Carlsbad WRF Carlsbad WRF Expansion Average Daily Demand During Month (mgd) 9-28 January 2012 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Draft Report/Chapter 9.doc As shown in Figure 9.8, the Carlsbad WRF needs to be expanded by about 4.0 mgd to meet the MMD of 11.0 mgd. It is assumed that the existing 4-mgd plant would be expanded by 4 mgd to 8 mgd to meet the Phase III demands. The capital cost, details of which are discussed in Chapter 10, is estimated at $7.0 M. Based on the seasonal peaking factor of 1.7, the existing MMD supply capacity of 7.6 mgd corresponds to an average annual demand of 5,008 afy. Based on an average annual Phase III demand of 7,414 afy, the expansion is assumed to add 2,406 afy of potential demand. Based on an annual demand increase of 2,406 afy made possible by this expansion, the unit cost would be $211 per acre-foot for capital costs. As shown in Figure 9.9, the Carlsbad WRF needs to be expanded by 6.4 mgd to meet the projected built out demand of 13.5 mgd. For planning purposes, it is assumed that the existing 4-mgd plant would be expanded by 7 mgd, or 3 mgd of additional capacity after completion of Phase III. The estimated capital cost, details of which are discussed in Chapter 10, is estimated at $5.5 M. Based on an average annual build out demand of 9,106 afy, the expansion is assumed to add 1,692 afy of potential demand beyond the capacity of the Phase III system. Based on an annual demand of 1,692 afy made possible by this expansion, the unit cost would be $236 per acre-foot. Note that the unit cost developed in Chapter 4 is based on a single 7-mgd expansion rather than two expansions, the first phase of 4-mgd and the second phase of 3-mgd. As discussed in Chapter 4, using seasonal storage in Mahr Reservoir could reduce the required treatment capacity at Carlsbad WRF by about 1 mgd for one month in the entire summer. As shown in Figure 9.10, using Mahr Reservoir as a source of supply in the maximum months can reduce the required build out expansion from 6.4 mgd to 6.0 mgd. However, using seasonal storage to this degree will require very strict accounting and operations of the water in Mahr Reservoir in order to avoid running short on supplies in the maximum month. If demands peak higher in a year due to higher temperatures or low rainfall, supply shortfalls could ensue. It is therefore recommend expanding the Carlsbad WRF by 7 mgd and only using Mahr Reservoir as seasonal and emergency storage backup supply. January 2012 9-29 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Draft Report/Chapter 9.doc Figure 9.10 Build Out Supply Strategy with Seasonal Storage 9.3.9 Utilization of Abandoned Assets As discussed in Chapter 2, CMWD has identified several abandoned assets that could potentially be utilized to minimize CMWD’s new capital expenditures. This analysis evaluated the potential cost benefit of using the existing abandoned assets. 9.3.9.1 Existing 20-inch Pipeline along El Camino Real An abandoned 20-inch diameter pipeline runs 3.5 miles along El Camino Real from Faraday Avenue to Chestnut Avenue. The pipeline was originally part of CMWD’s potable distribution system. Expansion Segments 3 and 5 include approximately 2.2 miles of 8-inch diameter pipeline following the alignment of the abandoned pipeline. It is anticipated that utilizing this pipeline would require sliplining the 20-inch diameter abandoned pipeline with an 8-inch diameter pipeline for the recycled water system. The anticipated capital costs associated with utilizing the abandoned asset, along with the anticipated cost savings resulting from not installing a new parallel pipeline, are shown in Table 9.10. 2.0 2.0 2.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 2.0 0.9 0.8 1.2 4.0 4.0 4.0 4.0 4.0 4.0 4.0 4.0 2.4 0.2 2.3 4.2 5.6 5.7 4.9 4.1 0.2 0.25 0.75 0 2 4 6 8 10 12 14 16 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Average Daily Demand During Month (mgd) Meadowlark WRF Carlsbad WRF Carlsbad WRF Expansion Mahr Reservoir Seasonal Storage Average Daily Demand During Month (mgd) 9-30 January 2012 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Draft Report/Chapter 9.doc Table 9.10 El Camino Real Abandoned Pipeline Alternative Recycled Water Master Plan Carlsbad Municipal Water District Alignment Pipeline Segment Length (ft) Estimated Construction Cost(1) Capital Cost(2) Capital Cost without Abandoned Asset(3) Difference(4) 3 2,300 $200,000 $310,000 $530,000 $220,000 5 9,600 $820,000 $1,255,000 $2,205,000 $950,000 Total 11,000 $1,020,000 $1,565,000 $2,735,000 $1,170,000 Notes: (1) Includes costs for sliplining based on unit costs discussed in Chapter 10. (2) Capital Costs include a construction cost contingency of 20 percent and additional markups for engineering and legal costs of 27.5 percent. (3) Capital Cost for component of pipeline along El Camino Real that could be substituted by utilization of abandoned asset. This is a portion of the capital cost listed in Table 9.4 for each alternative. (4) Anticipated savings from utilization of abandoned asset. As shown in Table 9.10, it is anticipated that utilization of the abandoned pipeline along El Camino Real could result in a cost savings of nearly $1.2 million. 9.3.9.2 Existing 21-inch TAP Connection A 21-inch diameter pipeline runs across natural open space from College Boulevard to Cannon Road south of Lake Calavera. The pipeline was part of the potable water system and CMWD currently plans to replace this pipeline. This pipeline could be used as an alternative to repurposing the failsafe pipeline in Expansion Segment 4. It is estimated that about 2 miles of the pipeline would be useful as a transmission main for recycled water to supply Oceanside customers (identified as a part of Expansion Segment 4B). It is anticipated that utilizing this pipeline would require sliplining the 21-inch diameter abandoned pipeline with an 8-inch diameter pipeline for the recycled water system. The anticipated capital costs associated with utilizing the abandoned asset, along with the anticipated additional cost to Expansion Segment 4B, are shown in Table 9.11. January 2012 9-31 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Draft Report/Chapter 9.doc Table 9.11 TAP Connection Alternative Recycled Water Master Plan Carlsbad Municipal Water District Alt. Pipeline Segment Length (ft) Estimated Construction Cost(1) Capital Cost(2) Original Capital Cost of Alternative 4B Capital Cost of Alternative 4B with TAP Alternative Difference 4B 10,800 $920,000 $1,410,000 $5,220,000 $6,630,000 $1,410,000 Total 10,800 $920,000 $1,410,000 $5,220,000 $6,630,000 $1,410,000 Notes: (1) Includes costs for sliplining based on unit costs discussed in Chapter 10. (2) Capital costs include a construction cost contingency of 20 percent and additional markups for engineering and legal costs of 27.5 percent. As shown in Table 9.11, it is anticipated that total capital cost if Alternative 4B was to use the TAP connection would be approximately $6.6 M, a $1.4 M additional cost over using the failsafe pipeline for delivery of recycled water to VID and Oceanside. However, the development of Expansion Segment 4 costs has assumed that the failsafe pipeline will be provided at no cost. This pipeline could serve as an alternative should the pipeline acquisition exceed this cost difference. In addition, if VID customers were not supplied as a part of Expansion Segment 4, the pipeline could serve as an alternative to allow service of Oceanside customers without needing to cross into VID’s service area. Note that, if Expansion Segment 4A is not implemented, this could potentially save the costs of connecting to the failsafe pipeline associated with Expansion Segment 4A. 9.3.10 Redundancy 9.3.10.1 Redundancy Pipeline for Carlsbad Village Expansion Segments 11 and 12 would be served through a single pipeline from Expansion Segment 2. To limit the potential for service interruptions, Expansion Segment 12 and Expansion Segment 5 could be looped with a 0.5-mile pipeline, allowing for redundancy in supplying the Carlsbad Village area. The estimated capital cost associated with adding this 0.5-mile pipeline is shown in Table 9.12. 9-32 January 2012 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Draft Report/Chapter 9.doc Table 9.12 Redundancy Pipeline for Carlsbad Village Recycled Water Master Plan Carlsbad Municipal Water District Alignment Diameter (in) Pipeline Length (ft) Estimated Construction Cost(1) Capital Cost(2) Chestnut Ave. from Valley Street to El Camino Real 12 4,200 $630,000 $965,000 Notes: (1) Based on unit costs discussed in Chapter 10. (2) Capital costs include a construction cost contingency of 20 percent and additional markups for engineering and legal costs of 27.5 percent. As shown in Table 9.12, it is anticipated that total capital cost for a pipeline between Expansion Segments 5 and 12 would be approximately $1.0 M. 9.3.10.2 Supply of Full System without Meadowlark WRF CMWD currently has the capability to maintain full supply of its recycled water system under MMD conditions with the ultimate supply capacity of Carlsbad WRF and with the supplemental potable connection at the Twin D Tanks, while Meadowlark WRF is offline. This analysis evaluates the additional capacity necessary to supply MDD conditions under built out conditions with Meadowlark WRF offline and the Gafner WRP no longer available. The results are shown in Table 9.13. Table 9.13 Analysis of Supply without Meadowlark WRF Recycled Water Master Plan Carlsbad Municipal Water District Source Built Out Capacity/Demand (mgd) Built Out Capacity/Demand(1) (gpm) Ultimate Carlsbad WRF 11.0 7,600 Potable Supplement 4.3 3,000 Total 15.3 10,600 Maximum Month Demand(2) 13.5 9,400 Balance +1.8 +1,200 Notes: (1) Although capacity is shown in units of gpm, supplies are calculated for maximum month demand conditions. Operational storage to accommodate daily peaking is discussed in Section 9.3.11. (2) MMD from build-out system including areas of potential development and neighboring agencies in addition to potential customers identified within CMWD’s service area. As discussed in Chapter 2, the existing potable water connection can supply 3,000 gpm of supplement water. Based on the supply analysis presented in Section 9.3.8, the ultimate supply capacity of Carlsbad WRF is recommended to be increased from 4 to 11 mgd. January 2012 9-33 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Draft Report/Chapter 9.doc As Zone 550 and Zone 660 typically receive flow from Meadowlark WRF, the Twin D pump station must be sized to meet demands of both of these zones (as the potable supplement connection and the Carlsbad WRF feeds Zone 384). Table 9.14 presents an analysis of the capacity of the Twin D pump station under ultimate demand conditions. This analysis is conducted under MMD conditions since operational storage is recommended to be incorporated into Zone 550 to accommodate daily peaking (see Section 9.3.11). Table 9.14 Twin D Capacity Analysis Recycled Water Master Plan Carlsbad Municipal Water District Booster Station Existing Pump Station Capacity (gpm) Built Out Zone 550 and 660 MMD (mgd) Built Out Zone 550 and 660 MMD(1) (gpm) Twin D 4,500 4.9 3,400 Notes: (1) As discussed in Section 9.3.11, operational storage is recommended to be included in Zone 550 to accommodate daily peaking. As shown in Table 9.14, the existing capacity of the Twin D pump station is sufficient to meet Maximum Day Demands for Zones 550 and 660 of the built out system. It should be noted that the pump station cannot accommodate peak hour demands of Zones 550 and 660. As discussed in Section 9.3.11, the storage analysis recommends operational storage within Zones 550 and 660. 9.3.11 Storage Analysis The storage analysis evaluates the existing storage capacity based on the evaluation criteria in Chapter 7 for operational and emergency storage. A definition for each category of storage criteria is summarized below. • Operational Storage: The storage required to buffer demand fluctuations under maximum day demand (MDD) conditions. The required operational storage is defined as 33 percent of MDD. • Short-term Emergency Storage: The storage volume required for preventing a reservoir from completely draining during an emergency situation such as a temporary supply outage or a demand spike. The required emergency storage is defined as 17 percent of MDD. A third component of storage used in CMWD’s system, seasonal storage, is treated as a source of supply and is discussed in more detail in Chapter 4. 9-34 January 2012 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Draft Report/Chapter 9.doc As described in Chapter 8, CMWD currently has 35.5 MG of storage, 32.0 MG of which is available in Mahr Reservoir. Operational and emergency storage requirements were calculated based on the evaluation criteria. Demands for Zone 742 (La Costa Ridge) are incorporated into Zone 550. For Zones 318 and 580, the reservoir capacity is assumed to be located in the larger Zone 384, from which each of these zones will be supplied. For Zones 550 and 660, demand in the existing system does not require operational storage as Meadowlark WRF supplies a greater flow than the demand of Zones 550 and 660. However, for the future system, it is anticipated that storage will be required for Zones 550 and 660 once demands in Zones 550 and 660 exceed available supply from Meadowlark WRF on a MMD basis. Note that demands for the La Costa Resort and Spa south golf course are incorporated into Zone 384, since the recommended supply alternative would include abandonment of Gafner WRP; although currently, operational storage for the La Costa Resort and Spa south golf course is provided by on-site ponds. Total future required operational and emergency storage requirements are compared to the existing storage in Table 9.15. Table 9.15 Storage Capacity Evaluation for Build-out Recycled Water Master Plan Carlsbad Municipal Water District Zone Built Out MMD (mgd) Operational Storage(1,2) (MG) Short-Term Emergency Storage(1,3) (MG) Total Required Storage (MG) Existing Storage (MG) Balance (MG) 660 0.6 0.2 0.1 0.3 0.0(4) -0.3 550 4.2 1.4 0.7 2.1 0.0(4) -2.1 Subtotal 4.8 1.6 0.8 2.4 0.0(4) -2.4 Subtotal w/ Mahr 4.8 1.6 0.8 2.4 32.0(4) +29.6 580 0.4 0.2 0.1 0.2 0.0 -0.2 384 8.0 2.7 1.4 4.0 3.5 -0.5 318 0.2 0.1 < 0.1 0.1 0.0 -0.1 Subtotal 8.7 2.9 1.5 4.3 3.5 -0.8 Total w/o Mahr 13.5 4.4 2.3 6.7 3.5 -3.2 Total w/ Mahr 13.5 4.4 2.3 6.7 35.5 +28.8 Notes: (1) Operational and Emergency Storage requirements are based on the evaluation criteria from Chapter 7. (2) Based on the evaluation criteria, Operational Storage is 33 percent of the MMD. (3) Based on the evaluation criteria, Emergency Storage is 17 percent of the MMD, or four hours. (4) Supplies from Meadowlark WRF are taken at a constant rate greater than the demand of Zones 550 and 660. Consequently, Operational Storage for Zone 550 is not needed. When necessary, Mahr Reservoir can be used to buffer supplies at Meadowlark WRF. January 2012 9-35 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Draft Report/Chapter 9.doc As shown in Table 9.15, a deficit of 3.2 MG is anticipated at build-out if capacity in Mahr Reservoir is not considered. Zone 550 and Zone 660 is grouped together as these zones are both fed from Meadowlark WRF. As shown in Table 9.15, a total storage volume of 2.4 MG is required for these zones. If there is sufficient MMD supplies such that capacity within Mahr Reservoir is not needed for seasonal storage, the required storage could be satisfied through use of Mahr Reservoir, assuming CMWD develops a method of replenishing Mahr Reservoir from its other supply sources (since daily demand in Zone 550 and Zone 660 will exceed supply from Meadowlark WRF). Otherwise, it is recommended that the ultimate system include 2.5 MG of new storage capacity for Zone 550. This can be met by rehabilitating the 2.5 MG Santa Fe I tank in Zone 660. Note that the demands for expansion segment Alternative 4C are used to calculate this storage requirement. The total required storage volume will be significantly less if Alternative 4C is not implemented. Zones 318, 384, and 580, as well as proposed Zones 425 and 742, are grouped together as these zones are all planned to be fed from Carlsbad WRF (Zone 384). As shown in Table 9.15, a total of 0.8 MG of storage is required for these zones. The hydraulic model predicted a significant decline in zone hydraulic grade line (HGL) across the pressure zone during peak hour demand conditions, especially to the north of the zone. The C Tank was predicted to empty during peak periods. As mentioned in Chapter 2, the base elevation of the C Tank is approximately 8 feet above the zone HGL of 384 ft-msl. This may result in the need for an additional storage reservoir in the north of the system. While rehabilitating the Santa Fe I tank would resolve the shortage shortfall anticipated at build out (excluding Mahr Reservoir), it is most likely not cost effective to connect to the Santa Fe I tank until Expansion Segment 4C is constructed. As Expansion Segment 4C is not part of Phase III, as separate storage analysis for Phase III was conducted, which is summarized in Table 9.16. As shown in Table 9.16, a storage shortfall of 2.0 MG is anticipated for Phase III when Mahr Reservoir is not included. Based on the assumption that CMWD would maintain operational storage within its distribution system under its control, additional storage is recommended to be placed at the existing Twin D tank site, sized at 2 MG. With this additional storage, PHD could then be supplied to Zones 550 and 660 from the Twin D storage. At build out, it is recommended to also rehabilitate the Santa Fe I tank and use this for storage. Hence, a total of 4.5 MG of new storage is recommended and included in the CIP. 9-36 January 2012 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Draft Report/Chapter 9.doc Alternatively, CMWD can use Mahr Reservoir or equalization basins at Carlsbad WRF to meet the deficit during Phase III and add storage in build out through rehabilitation of the Santa Fe I tank. However, to maintain control of storage within CMWD’s distribution system, the recommendation of this report is to add 2 MG of storage at the Twin D tank site as a part of Phase III and rehabilitate the Santa Fe I tank as a part of the build out phase. Table 9.16 Storage Capacity Evaluation for Phase III Recycled Water Master Plan Carlsbad Municipal Water District Zone MMD (mgd) Operational Storage(1,2) (MG) Short-Term Emergency Storage(1,3) (MG) Total Required Storage (MG) Existing Storage (MG) Balance (MG) 660 0.6 0.2 0.1 0.3 0.0 -0.3 550 2.9 1.0 0.5 1.5 0.0 -1.5 Subtotal 3.6 1.2 0.6 1.8 0.0 -1.8 Subtotal w/ Mahr 3.6 1.2 0.6 1.8 32.0 +30.2 580 0.4 0.2 0.1 0.2 -0.2 384 6.8 2.2 1.2 3.4 3.5 +0.1 318 0.2 0.1 0.0 0.1 -0.1 Subtotal 7.4 2.4 1.3 3.7 3.5 -0.2 Total w/o Mahr 11.0 3.6 1.9 5.5 3.5 -2.0 Total w/ Mahr 11.0 3.6 1.9 5.5 35.5 +30.0 Notes: (1) Operational and Emergency Storage requirements are based on the evaluation criteria from Chapter 7. (2) Based on the evaluation criteria, Operational Storage is 33 percent of the MMD. (3) Based on the evaluation criteria, Emergency Storage is 17 percent of the MMD, or four hours. 9.3.12 Pump Station Analysis This analysis compares the capacity of each existing pump station to the corresponding built out demands to determine whether additional pumping capacity is required. Table 9.17 presents a summary of this analysis. January 2012 9-37 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Draft Report/Chapter 9.doc Table 9.17 Ultimate Pump Station Capacity Analysis Recycled Water Master Plan Carlsbad Municipal Water District Booster Pumping Station Pressure Zone MMD (mgd) MMD (gpm) Required Capacity (gpm) Firm Capacity (gpm) Balance (gpm) Bressi PS 660 0.6 448 952 3,000 +2,552 Calavera PS 580 0.4 312 935(1) 1,200 +265 Twin D PS 550, 660 4.8 3,341 3,371 4,500 +1,159 Carlsbad WRF PS(2,3) all 14.0 9,722 9,722 10,000 +278 Notes: (1) No operational storage for daily peaking is included for Calavera PS in Zone 580. A peaking factor of 3.0 was applied. (2) For reliability purposes it is assumed that this PS needs be able to supply the system wide MMD with Meadowlark WRF out of service. (3) CMWD does not plan for standby pumping capacity at Carlsbad WRF. As shown in Table 9.17, all pump stations have sufficient pumping capacity to meet the projected demands. Hence, no pump station expansions are included in the CIP. Note that as Carlsbad WRF has occasionally been used in the past to serve PHD, if CMWD maintains the capability for supplying PHD from Carlsbad WRF, additional capacity may be required. The recommendation of this report is to maintain MMD pumping capacity. Hence, no pump station expansions are included in the CIP. 9.4 SUMMARY OF FUTURE SYSTEM RECOMMENDATIONS 9.4.1 Distribution System The recommendations detailed in this chapter are summarized in Table 9.18. Detailed cost estimates for each of these recommendations are included in the capital improvement program (CIP), which is presented in Chapter 10. 9-38 January 2012 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Draft Report/Chapter 9.doc Table 9.18 Future System Recommendations Recycled Water Master Plan Carlsbad Municipal Water District Phase Description Category Size/Capacity Phase III Expansion Alignment 2 Pipeline 17,500 feet Phase III Expansion Alignment 3 Pipeline 8,600 feet Phase III Expansion Alignment 4A Pipeline 1 vault Phase III Expansion Alignment 4A Pipeline 700 feet Phase III Expansion Alignment 4B Pipeline 23,200 feet Phase III Expansion Alignment 7 Pipeline 2,500 feet Phase III Expansion Alignment 8 Pipeline 6,500 feet Phase III Expansion Alignment 9 Pipeline 5,800 feet Phase III Expansion Alignment 10 Pipeline 3,400 feet Phase III Expansion Alignment 14 Pipeline 5,900 feet Phase III Expansion Alignment 15 Pipeline 2,300 feet Phase III Zone 384 Reservoir Storage 2 MG Phase III Increase Capacity of Carlsbad WRF Treatment 4 mgd Build-out Expansion Alignment 1 Pipeline 15,400 feet Build-out Expansion Alignment 4C Pipeline 63,800 feet Build-out Expansion Alignment 5 Pipeline 54,200 feet Build-out Expansion Alignment 6 Pipeline 3,900 feet Build-out Expansion Alignment 11 Pipeline 25,700 feet Build-out Expansion Alignment 12 Pipeline 8,100 feet Build-out Expansion Alignment 13 Pipeline 5,900 feet Build-out Expansion Alignment 16 Pipeline 1,400 feet Build-out Expansion Alignment 17 Pipeline 19,000 feet Build-out Expansion Alignment 18 Pipeline 5,400 feet Build-out Redundancy Pipeline Carlsbad Village Pipeline 4,200 feet Build-out Slipline Pipeline to Santa Fe Tank I Pipeline 3,600 feet Build-out Increase Capacity of Carlsbad WRF Treatment 3 mgd Build-out Rehabilitate Santa Fe Tank I Storage 2.5 MG January 2012 10-1 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 10 Chapter 10 CAPITAL IMPROVEMENT PROGRAM 10.1 INTRODUCTION The purpose of this chapter is to provide the Carlsbad Municipal Water District (CMWD) with a phased capital improvement program (CIP) that will guide CMWD with the implementation of recycled water system expansions in an effort to offset potable water demand requirements as much as possible. The previous chapter proposed a recommended recycled water system. In this chapter, cost assumptions are presented, followed by a description of the proposed Phase III and Build Out systems, and the proposed project phasing. This chapter is concluded with an estimate of the costs of the recommended CIP. 10.2 COST ESTIMATING ASSUMPTIONS 10.2.1 Scope and Accuracy Range The cost estimating criteria presented herein develop a consistent methodology for comparing alternatives. This methodology allows for different alternatives to be evaluated on the same cost basis. Cost estimates presented in this master plan are based on the current Engineering and News Record (ENR) 20 cities cost index of 9,035 published in May 2011. Future adjustments of cost estimates presented in this report can be estimated by increasing the estimated capital cost by the ratio of the future ENR to 9,035. The cost estimates presented in the CIP have been prepared for general master planning purposes and for guidance in project evaluation and implementation. The actual costs of a project will depend on actual labor and material costs, competitive market conditions, final project scope, implementation schedule, and other variable factors such as preliminary alignment generation, detailed utility surveys, and environmental and local considerations. The Association for the Advancement of Cost Engineering (AACE) defines an order-of- magnitude estimate for master plan studies as an approximate estimate made without detailed engineering data. It is normally expected that an estimate of this type would be accurate within +50 percent to -30 percent. This section presents the assumptions used in developing order of magnitude cost estimates for recommended facilities. The AACE International defines five different class estimate categories as summarized in Table 10.1. 10-2 January 2012 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 10 Table 10.1 Class Estimates Recycled Water Master Plan Carlsbad Municipal Water District Class Status of Design Accuracy Range Low Side High Side 5 N/A -20% to -50% +30% to +100% 4 1% to 5% -15% to -30% +20% to +50% 3 10% to 40% -10% to -20% +10% to +30% 2 30% to 70% -5% to -15% +5% to +20% 1 80% to 110% -3% to -10% +3% to +15% 5 Rough Order-of-Magnitude Planning Estimate 4 Detailed Planning Level Estimate 3 Project Budget Estimate 2 Detailed Project Control Estimate 1 Bid Check Estimate Note: Percentages are based on the construction cost value and not on an incremental subtotal after each percentage category The budgeting level estimates needed for planning purposes and CIPs are usually based on Class 5, and as such, the costs developed in this master plan shall be considered Class 5 estimates, unless noted otherwise. A definition of the five different class estimates is described below. Class 5. This estimate is considered as rough order-of-magnitude estimate. It is usually prepared based on limited information, where little more than proposed facility type, its location, and the capacity are known. Strategic planning purposes include, but are not limited to, market studies, assessment of viability, evaluation of alternate schemes, project screening, location and evaluation of resource needs and budgeting, and long-range capital planning. Examples of estimating methods used would be cost/capacity curves and factors, scale-up factors, and parametric and modeling techniques. Little time is expended in the development of this estimate. The typical expected accuracy range for this class estimate is -20 to -50 percent on the low side and +30 to +100 percent on the high side. Class 4. This estimate is prepared based on information where the preliminary engineering is 1 to 5 percent complete. Detailed strategic planning, business development, project screening, alternative scheme analysis, confirmation of economic and/or technical feasibility, and preliminary budget approval are needed to proceed with this class estimate. Examples of estimating methods used would include equipment and/or system process factors, scale-up factors, as well as parametric and modeling techniques. This estimate requires more time to develop. The January 2012 10-3 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 10 typical expected accuracy range for this class estimate is -15 to -30 percent on the low side and +20 to +50 percent on the high side. A Class 4 estimate may also be justified by the methods presented for this cost evaluation if suitable definitions of project components, individual consideration of special project components/conditions, and independent cost verifications are conducted. Commensurate reductions in project contingencies should also be considered for the Class 4 estimate. The following class estimates are typically used during the preliminary and final design stages of a project and are not applicable to estimates developed using this estimating guide. They are described in this report for information and consistency. These estimate classes include Class 3, Class 2, and Class 1: Class 3. This estimate is prepared to form the basis for the project authorization, and/or funding. Typically, engineering is 10 to 40 percent complete, and would comprise process flow diagrams, preliminary piping runs for major processes, facility layout drawings, and complete process and facility equipment lists. This estimate becomes the project control or project budget estimate until more detailed estimates are completed. Examples of methods used would be a high degree of detailed unit cost, and quantity takeoffs for major processes. Factoring and/or scale-up factors can be used for less significant or support areas of the project. This estimate requires a great deal of time to prepare, where actual equipment and processes have been designed. The typical expected accuracy range for this class estimate is -10 to -20 percent on the low side, and +10 to +30 percent on the high side. Class 2. This estimate is prepared to form a detailed control baseline for the project. Typically, engineering is 30 to 70 percent complete, and would comprise process flow diagrams, piping and instrument runs for all processes, final facility layout drawings, complete process and facility equipment lists, single-line diagrams for electrical components, and schedules. This estimate becomes the detailed project control estimate. Examples of methods used include a high degree of deterministic estimating, as well as detailed quantity takeoffs for all facility processes and/or systems, with little factoring and/or scale-up factors used, except for minor project support areas. This estimate usually becomes the final estimate and requires a great deal of line-item information, which can take significant time to prepare. The typical expected accuracy ranges for this class estimate are -5 to -15 percent on the low side and +5 to +20 percent on the high side. Class 1. This estimate is prepared to confirm the control baseline for the project. Typically, engineering is 80 to 100 percent complete, which comprises virtually all engineering and design documentation of the project, and complete project execution and commissioning plans. This estimate becomes the final control 10-4 January 2012 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 10 baseline of the project. Examples of methods used are the highest degree of deterministic estimating, with very detailed quantity takeoffs for all facility processes and/or systems of the project. This type of estimate usually becomes the bid check estimate and can require the most effort to create. The typical expected accuracy ranges for this class estimate are -3 to -10 percent on the low side and +3 to +15 percent on the high side. All classes of cost estimates described, and any resulting conclusions on project financial or economic feasibility or funding requirements, are prepared for guidance in project evaluation and implementation. The final costs of the project, and resulting feasibility, will depend on actual labor and material costs, competitive market conditions, actual site conditions, final project scope, implementation schedule, continuity of personnel and engineering, and other variable factors. Therefore, the final project costs will vary from the estimate developed using the information in this master plan. Because of these factors, project feasibility, cost-benefit ratios, risks, and funding needs must be carefully reviewed prior to making specific financial decisions or establishing project budgets to help ensure proper project evaluation and adequate funding. This evaluation is concerned only with estimates at the planning and conceptual phase of the projects for CMWD. Therefore, only Class 5 estimates have been developed. For the development of the CIP, a construction cost contingency and other markups will be applied consistent with Table 10.2. The markups are intended to account for costs of engineering, design, administration, and construction management. 10.2.2 Markups and Contingency The cost estimates are based on current perceptions of conditions at the project locations. These estimates reflect Carollo’s professional opinion of costs at this time and are subject to change as the project details are defined. Carollo has no control over variances in the cost of labor, materials, equipment, services provided by others, contractor’s methods of determining prices, competitive bidding, or market conditions, practices, or bidding strategies. Carollo cannot, and does not, warrant or guarantee that proposals, bids, or actual construction costs will not vary for the costs presented as shown. January 2012 10-5 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 10 Table 10.2 General Cost Estimating Assumptions Recycled Water Master Plan Carlsbad Municipal Water District Description Percent of Construction Cost Construction Cost 100.0% Construction Cost Contingency 20.0% Construction Cost + Contingency 120.0% Engineering and Design 10.0% Project Administration 2.5% Construction Management 5.0% Construction Inspection 10.0% Total Markups 127.5% Total Project Cost(1) 153.0% Note: (1) Percentages are based on the construction cost value and not on an incremental subtotal after each category. Total Project Cost = Construction Cost + Contingency x Total Markups. 10.2.3 Unit Construction Costs The construction cost estimates presented in this report are based on the unit construction costs listed in Table 10.3. Construction costs for recycled water system pipelines include pipe material, valves, appurtenances, excavation, installation, bedding material, backfill material, transport, and paving where applicable. The costs of acquiring easements for pipeline construction are not included in the estimates presented in this report. Table 10.3 Unit Construction Cost Recycled Water Master Plan Carlsbad Municipal Water District Category Unit Construction Cost Pipelines $/lineal ft 4-inch diameter 100 6-inch diameter 110 8-inch diameter 120 12-inch diameter 150 16-inch diameter 290 18-inch diameter 350 20-inch diameter 400 24-inch diameter 500 30-inch diameter 650 36-inch diameter 750 10-6 January 2012 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 10 Table 10.3 Unit Construction Cost Recycled Water Master Plan Carlsbad Municipal Water District Category Unit Construction Cost Special Pipeline Construction Markup (%) or $/lineal ft Slip-lining(1) (8" into a 21") $85 /lineal ft Booster Pumping Stations – New Construction $/hp < 100 hp $6,000 100 to < 500 hp $4,500 500 hp and greater $3,500 Storage $/gallon < 1 MG $2.00 1 to < 2 MG $1.75 2 to < 5 MG $1.50 5 MG and greater $1.25 Miscellaneous $/unit Customer Laterals $4,000 $/lateral Enclosure Structures $300 $/sf PRV (in pre-existing vault) $50,000 $/station Note: (1) The unit cost for sliplining was developed based on the elevation differences, diameter, and length of the TAP connection. It is assumed that the unit construction costs would be similar for the other projects requiring sliplining of existing pipelines. For booster pumping stations (PS), unit costs are included based on the required horsepower assuming the project involves a new PS requiring new piping and all associated appurtenances. If a PS project only requires the replacement or addition of a pump to an existing PS, the unit costs will be evaluated on a per site basis at that time. Unit costs for PSs are estimated per horsepower of design size. 10.2.4 Excluded Costs There are several other components that may be needed to support the development of major water supply facilities. Since most of these items are unique and project specific, they should be applied on a project-by-project basis. Therefore, no unit costs were included in Table 10.3 for the following items: • Land acquisition. Cost for purchasing land or right of way are not included due to variability of real estate market conditions. • Power transmission lines. The cost of these to support a major pumping or treatment is often on a shared cost basis with the power utility. • Maintenance roads. If pipelines are installed in remote areas, maintenance roads are sometimes required to access the facilities. January 2012 10-7 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 10 • Overall program management. If the sheer magnitude of the capital cost program exceeds the capacity of City of Carlsbad staff to manage all of the work, then the services of a program management team may be required. • Public information program. Depending on the relative public acceptability of a major water facility or a group of facilities, there may be a need for a public information program, which could take many different shapes. • Customer retrofits. Retrofit costs are associated with separating the customer’s existing potable water system from a new recycled water system. An example would be a park where restroom and drinking fountain water supply pipes would need to be isolated from an existing irrigation system. Additional costs include posting signage, which identifies where recycled water is being used. Customer retrofits are one-time costs and are dependent upon the complexity of existing irrigation systems at each individual site. This cost estimate excludes cost of customer retrofits. • Foundation requirements. Foundation reinforcement or support requirements are very site specific with regard to necessary method and type, and a geotechnical study is typically needed to determine such requirements. These costs, therefore, have not been included in any of the unit cost curves. • Other costs. These costs may be necessary on some projects and could include environmental mitigation and permitting costs; special legal, administrative, or financial assistance; easements or rights-of-way and land acquisition costs; and expediting costs, such as separate material procurement contracts. These other costs typically range from 5 to 15 percent of construction cost. 10.3 SUMMARY OF RECOMMENDATIONS This section summarizes the projects recommended in Chapter 8 (Existing System Analysis) and Chapter 9 (Future System Analysis). The detailed cost estimate for each component of each project is presented followed by a summary of the cost estimate data by project type and phase. 10.3.1 Project Cost Estimates Table 10.4 presents the detailed cost estimate for each component of the projects based on the recommended projects and quantities described in Chapters 8 and 9 and the unit costs presented in Table 10.3. 10-8 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 10 Table 10.4 Detailed Project List Recycled Water Master Plan Carlsbad Municipal Water District Project ID Category Description Planning Phase Size Unit Capacity Unit Cost Construction Cost Capital Cost P01 Pipeline Expansion Alignment 1 Build-out 3,100 ft 4 in 100 $ per lineal ft $310,000 $475,000 P02 Pipeline Expansion Alignment 1 Build-out 5,200 ft 6 in 110 $ per lineal ft $575,000 $880,000 P03 Pipeline Expansion Alignment 1 Build-out 7,100 ft 8 in 120 $ per lineal ft $855,000 $1,310,000 P04 Pipeline Expansion Alignment 1 Build-out 58 meters 4,000 $ per meter $235,000 $360,000 P05 Pipeline Expansion Alignment 2 Phase III 1,300 ft 6 in 110 $ per lineal ft $145,000 $225,000 P06 Pipeline Expansion Alignment 2 Phase III 3,700 ft 8 in 120 $ per lineal ft $445,000 $685,000 P07 Pipeline Expansion Alignment 2 Phase III 3,900 ft 12 in 150 $ per lineal ft $585,000 $900,000 P08 Pipeline Expansion Alignment 2 Phase III 200 ft 16 in 290 $ per lineal ft $60,000 $95,000 P09 Pipeline Expansion Alignment 2 Phase III 4,900 ft 20 in 400 $ per lineal ft $1,960,000 $3,000,000 P10 Pipeline Expansion Alignment 2 Phase III 3,500 ft 24 in 500 $ per lineal ft $1,750,000 $2,680,000 P11 Pipeline Expansion Alignment 2 Phase III 18 meters 4,000 $ per meter $75,000 $115,000 P12 Pipeline Expansion Alignment 3 Phase III 3,000 ft 6 in 110 $ per lineal ft $330,000 $505,000 P13 Pipeline Expansion Alignment 3 Phase III 1,400 ft 8 in 120 $ per lineal ft $170,000 $265,000 P14 Pipeline Expansion Alignment 3 Phase III 4,200 ft 12 in 150 $ per lineal ft $630,000 $965,000 P15 Pipeline Expansion Alignment 3 Phase III 2 meters 4,000 $ per meter $10,000 $20,000 P16 Pipeline Expansion Alignment 4A Phase III 2 interc. 100,000 $ per conn. $200,000 $310,000 P17 Pipeline Expansion Alignment 4A Phase III 700 ft 12 in 150 $ per lineal ft $105,000 $165,000 P18 Pipeline Expansion Alignment 4A Phase III 1 meters 4,000 $ per meter $5,000 $10,000 P19 Pipeline Expansion Alignment 4B Phase III 500 ft 4 in 100 $ per lineal ft $50,000 $80,000 P20 Pipeline Expansion Alignment 4B Phase III 4,000 ft 6 in 110 $ per lineal ft $440,000 $675,000 P21 Pipeline Expansion Alignment 4B Phase III 5,400 ft 8 in 120 $ per lineal ft $650,000 $995,000 P22 Pipeline Expansion Alignment 4B Phase III 11,700 ft 12 in 150 $ per lineal ft $1,755,000 $2,690,000 P23 Pipeline Expansion Alignment 4B Phase III 1,600 ft 16 in 290 $ per lineal ft $465,000 $715,000 P24 Pipeline Expansion Alignment 4B Phase III 9 meters 4,000 $ per meter $40,000 $65,000 P25 Pipeline Expansion Alignment 4C Build-out 2,600 ft 4 in 100 $ per lineal ft $260,000 $400,000 P26 Pipeline Expansion Alignment 4C Build-out 22,600 ft 6 in 110 $ per lineal ft $2,490,000 $3,810,000 P27 Pipeline Expansion Alignment 4C Build-out 11,400 ft 8 in 120 $ per lineal ft $1,370,000 $2,100,000 July 2011 10-9 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 10 Table 10.4 Detailed Project List Recycled Water Master Plan Carlsbad Municipal Water District P28 Pipeline Expansion Alignment 4C Build-out 27,200 ft 12 in 150 $ per lineal ft $4,080,000 $6,245,000 P29 Pipeline Expansion Alignment 4C Build-out 369 meters 4,000 $ per meter $1,480,000 $2,265,000 P30 Pipeline Expansion Alignment 5 Build-out 7,000 ft 4 in 100 $ per lineal ft $700,000 $1,075,000 P31 Pipeline Expansion Alignment 5 Build-out 9,300 ft 6 in 110 $ per lineal ft $1,025,000 $1,570,000 P32 Pipeline Expansion Alignment 5 Build-out 33,700 ft 8 in 120 $ per lineal ft $4,045,000 $6,190,000 P33 Pipeline Expansion Alignment 5 Build-out 4,200 ft 12 in 150 $ per lineal ft $630,000 $965,000 P34 Pipeline Expansion Alignment 5 Build-out 31 meters 4,000 $ per meter $125,000 $195,000 P35 Pipeline Expansion Alignment 6 Build-out 2,100 ft 6 in 110 $ per lineal ft $235,000 $360,000 P36 Pipeline Expansion Alignment 6 Build-out 1,800 ft 8 in 120 $ per lineal ft $220,000 $340,000 P37 Pipeline Expansion Alignment 6 Build-out 3 meters 4,000 $ per meter $15,000 $25,000 P38 Pipeline Expansion Alignment 7 Phase III 2,500 ft 8 in 120 $ per lineal ft $300,000 $460,000 P39 Pipeline Expansion Alignment 8 Phase III 6,500 ft 12 in 150 $ per lineal ft $975,000 $1,495,000 P40 Pipeline Expansion Alignment 8 Phase III 1 meters 4,000 $ per meter $5,000 $10,000 P41 Pipeline Expansion Alignment 9 Phase III 1,600 ft 6 in 110 $ per lineal ft $180,000 $280,000 P42 Pipeline Expansion Alignment 9 Phase III 4,200 ft 8 in 120 $ per lineal ft $505,000 $775,000 P43 Pipeline Expansion Alignment 9 Phase III 4 meters 4,000 $ per meter $20,000 $35,000 P44 Pipeline Expansion Alignment 10 Phase III 3,400 ft 8 in 120 $ per lineal ft $410,000 $630,000 P45 Pipeline Expansion Alignment 10 Phase III 2 meters 4,000 $ per meter $10,000 $20,000 P46 Pipeline Expansion Alignment 11 Build-out 2,700 ft 4 in 100 $ per lineal ft $270,000 $415,000 P47 Pipeline Expansion Alignment 11 Build-out 7,500 ft 6 in 110 $ per lineal ft $825,000 $1,265,000 P48 Pipeline Expansion Alignment 11 Build-out 10,400 ft 8 in 120 $ per lineal ft $1,250,000 $1,915,000 P49 Pipeline Expansion Alignment 11 Build-out 5,100 ft 12 in 150 $ per lineal ft $765,000 $1,175,000 P50 Pipeline Expansion Alignment 11 Build-out 29 meters 4,000 $ per meter $120,000 $185,000 P51 Pipeline Expansion Alignment 12 Build-out 500 ft 4 in 100 $ per lineal ft $50,000 $80,000 P52 Pipeline Expansion Alignment 12 Build-out 2,500 ft 6 in 110 $ per lineal ft $275,000 $425,000 P53 Pipeline Expansion Alignment 12 Build-out 5,100 ft 8 in 120 $ per lineal ft $615,000 $945,000 P54 Pipeline Expansion Alignment 12 Build-out 14 meters 4,000 $ per meter $60,000 $95,000 P55 Pipeline Expansion Alignment 13 Build-out 5,900 ft 8 in 120 $ per lineal ft $710,000 $1,090,000 P56 Pipeline Expansion Alignment 13 Build-out 8 meters 4,000 $ per meter $35,000 $55,000 P57 Pipeline Expansion Alignment 14 Phase III 1,400 ft 4 in 100 $ per lineal ft $140,000 $215,000 P58 Pipeline Expansion Alignment 14 Phase III 1,000 ft 6 in 110 $ per lineal ft $110,000 $170,000 10-10 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 10 Table 10.4 Detailed Project List Recycled Water Master Plan Carlsbad Municipal Water District P59 Pipeline Expansion Alignment 14 Phase III 3,500 ft 8 in 120 $ per lineal ft $420,000 $645,000 P60 Pipeline Expansion Alignment 14 Phase III 6 meters 4,000 $ per meter $25,000 $40,000 P61 Pipeline Expansion Alignment 15 Phase III 1,000 ft 4 in 100 $ per lineal ft $100,000 $155,000 P62 Pipeline Expansion Alignment 15 Phase III 1,300 ft 6 in 110 $ per lineal ft $145,000 $225,000 P63 Pipeline Expansion Alignment 15 Phase III 9 meters 4,000 $ per meter $40,000 $65,000 P64 Pipeline Expansion Alignment 16 Build-out 1,400 ft 6 in 110 $ per lineal ft $155,000 $240,000 P65 Pipeline Expansion Alignment 16 Build-out 3 meters 4,000 $ per meter $15,000 $25,000 P66 Pipeline Expansion Alignment 17 Build-out 1,800 ft 4 in 100 $ per lineal ft $180,000 $280,000 P67 Pipeline Expansion Alignment 17 Build-out 13,200 ft 6 in 110 $ per lineal ft $1,455,000 $2,230,000 P68 Pipeline Expansion Alignment 17 Build-out 4,000 ft 8 in 120 $ per lineal ft $480,000 $735,000 P69 Pipeline Expansion Alignment 17 Build-out 26 meters 4,000 $ per meter $105,000 $165,000 P70 Pipeline Expansion Alignment 18 Build-out 4,700 ft 6 in 110 $ per lineal ft $520,000 $800,000 P71 Pipeline Expansion Alignment 18 Build-out 700 ft 8 in 120 $ per lineal ft $85,000 $135,000 P72 Pipeline Expansion Alignment 18 Build-out 17 meters 4,000 $ per meter $70,000 $110,000 P73 Pipeline Retrofit Customers near Existing System Phase III 30 meters 4,000 $ per meter $120,000 $185,000 P74 Pipeline Redundancy Looping Build-out 4,200 ft 12 in 150 $ per lineal ft $630,000 $965,000 P75 Pipeline Customers Near Existing System Phase III 17 meters 4,000 $ per meter $70,000 $110,000 P76 Storage C Tank Chlorination and Mixing System Existing $75,000 $115,000 P77 Storage Zone 384 Reservoir Phase III 2.0 MG 1,500,000 $ per MG $3,000,000 $4,590,000 P78 Pipeline Pipeline to Santa Fe Tank I Build-out 3,600 ft 12 in 150 $ per lineal ft $540,000 $830,000 P79 Storage Rehabilitate Santa Fe Tank I Build-out 2.5 MG 1,500,000 $ per MG $3,750,000 $5,740,000 P80 Treatment Increase Capacity of Carlsbad WRF Phase III 4.0 mgd separate estimate $5,490,000 $7,000,000 P81 Treatment Increase Capacity of Carlsbad WRF Build-out 3.0 mgd separate estimate $4,300,000 $5,500,000 Total $56,180,000 $83,680,000 January 2012 10-11 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 10 As shown in Table 10.4, the total estimated construction cost of all identified projects is $56,180,000, and the corresponding capital cost with the additional markups and contingencies from Table 10.2 is $83,680,000. While most projects listed in Table 10.4 are based on the unit costs presented in Table 10.3, separate estimates were developed for the increases in treatment plant capacity (Project ID P80 and P81) and are included in Appendix B. Additional lump sum costs were used for the connection to the failsafe pipeline (Project ID P16) and the C Tank Chlorination and Mixing System (Project ID P76). For conservative planning purposes, unit costs for the rehabilitation of the Santa Fe Tank (Project ID P79) were assumed to be similar to new construction. Project Phasing Existing system recommendations, summarized in Chapter 8, are discussed separately as an existing phase. It is anticipated that these improvements would be implemented at the same time as Phase III. As discussed in Chapter 9, the system expansions are divided into two 10-year phases, Phase III and the Build-out Phase. The system expansions of the recommended system are described by phase below. Existing: The existing system analysis consisted of one recommendation - a chlorination system for the C Tank. The capital cost for this recommendation is estimated as $0.1 M. Phase III (2011-2020): Phase III includes the most feasible alignments as described in Chapter 9. This would expand CMWD’s recycled water system to the north area of Carlsbad and begin initial expansion into the neighboring agency through wholesale service to Shadowridge Golf Course. The overall system cost of these expansions is estimated at $32.3 M; and therefore would require a further increase in recycled water funds, either generated by rates and/or outside funding. It is assumed that the opportunities for funding would increase in the next decade to accommodate the increase in annual recycled water system expansion costs. Build-out Phase (2021-2030): The Build-out Phase includes the expansion alignments not included in Phase III, as well as the backbone pipelines to the potential new developments with uncertain timing. The overall system cost of these build out expansions is estimated at $51.3 M, which is about double the cost of the Phase III expansion. Hence, a greater level of revenue generation from rates and outside funding would be required to implement these projects. 10-12 January 2012 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 10 10.4 CAPITAL IMPROVEMENT PROGRAM 10.4.1 CIP by Planning Phase As discussed previously, the CIP is divided into two phases. The first phase consists of the projects to be implemented as a part of the Phase III improvement program, while the second phase consists of the remaining projects anticipated through build-out of the recycled water system. Table 10.5 summarizes the breakdown of costs for each of the two phases (shown in million dollars). Table 10.5 Capital Cost by Planning Phase and Project Type Recycled Water Master Plan Carlsbad Municipal Water District Project Type Existing Phase III Build-out Phase Total Pipelines $0.0 $20.7 $40.1 $60.7 Treatment $0.0 $7.0 $5.5 $12.5 Storage $0.1 $4.6 $5.7 $10.4 Total $0.1 $32.3 $51.3 $83.7 Note: (1) Capital Costs are based on the cost assumptions discussed in Section 10.2. Detailed information for each project can be found in Table 10.4. As shown in Table 10.5, the capital cost for Phase III is estimated at $32.3 M while the capital cost associated with the Build-out Phase is estimated at $51.3 M. Figure 10.1 presents the capital costs for each identified phase. $0.1 $32.3 $51.3 $0 $10 $20 $30 $40 $50 $60 Existing Phase III Build-out PhaseCapital Cost($ million) Figure 10.1 Capital Cost by Phase The locations of the projects included in Phase III and the Build-out Phase are shown on Figure 10.2. "C" Tank Carlsbad WRF Gafner WRP Mahr Reservoir Meadowlark WRF Agua HediondaLagoon Twin "D" TanksCami n o R e al E lm A veMarron Rd C arls b a d Blv d Hig hla n d Dr A londra W ayPaseo Nort eCollege BlvdPalomar Airport Aviara Pkwy El Fuerte StCosta AvePoinsettia LnTam arack AveCannon Rd Calle BarcelonaRanch o Santa FeCalavera PS CWRF PS Bressi PS "D" Tank PSPacific Ocean Encinitas Batiquitos Lagoon Buena VistaLagoon Oceanside Shadowridge WRP LakeCalavera Corintia Meter OMWDMeter 8" 20 San Marcos Vista Encinitas Oceanside 3 17 5 8 2 7 6 1 9 11 11 13 12 10 14 16 18 4 15 2 0 "8"16"1 2 " 8" 8" 8 " 8 " 8" 8"8" 8 "8"8"8"8"8"8"8"8"8 " 8 " 8"8"8" 8"8" 8"8" 8 " 8" 8"8"8"8"8"8"8"8 " 8"8"8" 8 " 8" 8" 8"8"8"8 " 8 " 8"8"8"8"8"8"8" 8" 8 " 8"8"12"8" 8"20"8"8"8" 1 2" 8" 8"8"8 " 8" 8" 8"8"8"8 " C017 C177 C179 C170 C169 C166 C178 C165 C164 C163 C161 C064 C031 C158 C126 C116 C157 C156 C155 C153 C152 C151 C149 C148C146 C145C144 C143 C102 C123 C103 C101 C105 C111 C114 C129 C134 C139C121 C124 C115 C113 C128 C108C130 C127 C118 C122 C131C120 C133 C107 C109 C140 C141 C104 C098 C100 C005 C001 C008 C071 C062 C087 C010 C088 C041 C068 C051 C063 C037 C078 C018C047 C046 C003 C019 C013 C027 C004 C021 C022 C007 C016 C036 C015 C006 Legend Recycled Water FacilitiesInactive WRP Pump StationPRV Meter WRF Tank Reservoir Potential Expansion SegmentsPhase IIIBuild OutDevelopment AreasAlready ConstructedExisting Recycled Water PipelinesDiameterLess than 6"6" to 8"10" to 14"16" and largerFuture DevelopmentResidential All OthersDevelopment not anticipated toutilize Recycled Water (Small Parcel)OtherFreewaysMajor RoadsLocal StreetsRailroadsWater BodyCarlsbad Municipal Water District BoundaryCarlsbad City LimitsSan Diego County 0 5,000 10,000Feet Figure 10.2Phasing of Potential Expansion SegmentsRecycled Water Master PlanCarlsbad Municipal Water DistrictFILENAME: c:\pw_working\projectwise\lwang\d0102644\Figure_10_2-Phasing of Potential Expansion Segments.mxdDATE: 1/14/2011 10-14 January 2012 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 10 This page intentionally left blank. January 2012 10-15 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 10 10.4.2 CIP by Project Type As shown in Table 10.5, pipelines represent the largest component of the total capital cost at about $61 M. Treatment and storage are similar in cost, at approximately $11 M and $10 M, respectively. Figure 10.3 presents the capital cost by project type graphically. Pipelines $60.7M 73% Treatment $12.5M 15% Storage $10.4M 12% Total Build Out CIP $83.7 million Figure 10.3 Capital Cost by Project Type 10.4.3 Escalated CIP As discussed in Chapter 9, it is anticipated that completing the infrastructure to support Phase III will require approximately 5 years with an additional 5 years to connect all the customers to the distribution system. It is assumed that the Build-out Phase will follow a similar schedule. Based on this schedule, the approximate timeline for implementation of the two phases are shown in Table 10.6. Table 10.6 Timeline of Phasing Recycled Water Master Plan Carlsbad Municipal Water District Phase Design and Construction of Infrastructure Connection of Customers Phase III 2011 – 2015 2015 – 2020 Build-out 2021 - 2025 2025 – 2030 10-16 January 2012 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 10 The estimated escalated capital project costs are shown in Table 10.7. Cost escalation is calculated with a 3-percent inflation rate and uses the mid-year of each estimated phase of implementation. It is assumed that the existing system improvements would be incorporated into construction of Phase III. The mid-year of Phase III is 2013 while the mid-year of the Build-out Phase is 2023. A base year of 2010 was used to calculate cost escalation. Table 10.7 Escalated CIP by Planning Phase Recycled Water Master Plan Carlsbad Municipal Water District Phase Capital Cost Escalated Capital Cost Existing $0.1 $0.2 Phase III $32.3 $35.3 Build-out $51.3 $75.4 Total $83.7 $110.9 Note: (1) Calculation of escalated cost assumes a baseline year of 2010 and an inflation rate of 3 percent. Figure 10.4 depicts the escalated capital cost as compared to the present day cost graphically. $0.1 $32.3 $51.3 $0.2 $35.3 $75.4 $0 $10 $20 $30 $40 $50 $60 $70 $80 $90 Existing Phase III Build-out PhaseCapital Cost($ million)Capital Cost Escalated Capital Cost Figure 10.4 Escalated Capital Cost January 2012 10-17 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 10 As shown in Figure 10.4, the escalated capital cost figures more significantly into the Build-out Phase than Phase III. The anticipated unit cost of recycled water for each expansion phase is compared with the projected cost of imported water in Figure 10.5. As shown, the average unit cost for each phase is below the projected imported water costs for the same time period. Unit costs were calculated using annualized capital cost based on a depreciation period of 50 years and six (6) percent interest. $0 $500 $1,000 $1,500 $2,000 $2,500 2010 2015 2020 2025 2030Unit Cost ($/af)Year Treatment and Storage Conveyance Treated Imported Water Cost (SDCWA)Projection Recycled Water System Expansion Phase III Build Out Figure 10.5 Comparison of Unit Costs to Imported Water Based on the potable water cost curve presented in Figure 10.5, it can be concluded that the expansion of CMWD’s recycled water system in both Phase III and through Build Out conditions is a cost-effective alternative to potable water supply. In addition to the cost benefit, recycled water provides increased supply reliability, especially during drought periods, and allows CMWD to remain more in control of the overall water supply cost for its customers. 10-18 January 2012 pw://Carollo/Documents/Client/CA/Carlsbad/8308A00/Deliverables/Report/Chapter 10 This page intentionally left blank.