The following information was researched and written by Elizabeth Bettenhausen.
She writes: “This initial description is neither comprehensive nor complete but does aspire to accuracy.” Sources are cited at the end of this entry.
1. Level of Water Use
1.1 The Equivalent Domestic Unit (EDU) would be raised from 12 to 18 units.1 The EDU is defined as the actual average bimonthly residential use.
EDUs are allocated to commercial units, but they have an effect only when surcharges are placed on potable water use. Otherwise allocated EDUs place no constraints on actual use of water. However, raising the EDU average for residential users is construed in the Water Master Plan as effecting a 50% increase for commercial use as well. 2
Over 70% of residential customers use 12 EDU or less every two months (General Manager’s Report, August 23, 2003).
One EDU is 748 gallons. The average quantity of potable water used in a residence is thus 147 gallons every day (8,976 gallons in two months.)To raise the EDU’s value from 12 to 18 posits a 50% increase in “the maximum goal of average residential water use”. 1 With the average increased to 18, the daily use would be 220 gallons (13,464 gallons in two months) for each residence.
1.2 According to CCSD, raising the EDUs from 12 to 18 is needed
· “to provide a quality of life increase ” 2,3
· because “[l]ocal Cambrians have a long history of shouldering water shortage emergencies and rate surcharges to curb demand.” 3
· “to provide some relief to existing customers from current water conserving measures that have evolved from years of shortages.” 4
2. Recycled Water Distribution Plan
2.1 Recycling is construed primarily as a means of “drought-proofing” to serve “the community’s investments in landscaping.” 5
2.2 Only sites with “the larger landscaped areas” would be served. 5
2.3 Only those sites in proximity to a proposed distribution pipeline would be served. 5
2.4 “Th[e] application rate was calculated for turf-type vegetation because the recycled water will be mainly used for irrigation of turf.” (Task 3, Final Draft Recycled Water Distribution Plan, Section 2, p. 5)
2.5 The estimation of residential customers for recycling is based only on current use of recycled water for irrigation with current accessibility. 6 No consideration of greywater use is made in Task 3.
3. Task 3, Final Draft Potable Water Distribution System Analysis
3.1 Pipeline improvements are proposed to provide residential fire flow at least 40-60% higher than residential areas “typically” have and in Cambria currently have. 8
3.2 This increase is proposed because of “the high fuel loads [forest?] and close proximity of the residences in these areas….” 7,8
4. Reliability of water service
4.1 If the number of water meters is increased by more than 10%, “a 90 percent or 95 percent level of reliability” will not be reached. 9
4.2 However, the claims regarding 90-95% reliability here are qualified at the end of the section in reference to conservation.10 Since the surcharge brought about a 13% reduction in water use in July and August of 2007, voluntary conservation
4.3 The installation of new meters and the recovery of some of the 12% loss of obtained water would further offset the 90-95% reliability shortfall. 11
SOURCES CITED
1 CCSD Minutes, p.10, July 24, 2003:
“Director Sanders moved that the Board select desalination as the alternative water source for Cambria and that the capacity of the plant be limited to Scenario 4 which is 4,650 total residential hookups plus an increment of additional water for existing residents that would take the maximum goal of average residential water use from 12 to 18 units. Director Cobin seconded. Roll Call Vote: Unanimously approved.”[i]
2 “Additionally, this quality of life increase allows for the same percent increase in
commercial consumption or for future commercial growth. Thus, the projected annual water demand, with the 50 percent increase above baseline use and 1.66 persons per household, is1,514 AF (for build-out Scenario 4) to 1,709 AF (for build-out Scenario 3). The dry season demands, with the same 50 percent increase above baseline and 1.66 persons per household, equate to 888 AF (Scenario 4) to 1,003 AF (Scenario 3), as shown in Table 2-7 provided below.” (Task Four: Assessment of Long-Term Water Supply Alternatives, Section 2, p. 19)
3CCSD Urban Water Management Plan:
“Desalination Facility Sizing and Enhancements to Increase Supply Reliability
Local Cambrians have a long history of shouldering water shortage emergencies and rate surcharges to curb demand. The typical residential water use in Cambria is approximately 0.161 acre-feet per year, or about 12 hundred cubic feet (ccf) per bi-monthly billing period. In planning for a future water supply, the District’s Board expressed a desire to provide a quality of life increase to allow about 18 ccf per bi-monthly period (0.25 acre-feet per year) for a typical residential user.” p. 3.2
4Water Master Plan, 3.6 Future Demands:
“During its July 24, 2003 Board meeting, staff was requested to plan for up to 18 ccf/bi-monthly billing period (which equals 0.248 AFA) for a typical residential connection. This directive was based in part on a desire to provide some relief to existing customers from current water conserving measures that have evolved from years of shortages. When compared to the December 8, 2000 Baseline Water Supply Analysis report data, this represents an increase of approximately 50 percent for the residential component.” (Section 3, Water Demand Projections, p. 23)
5 Task 3, Final Draft Recycled Water Distribution Plan, p. ES-1:
“The use of recycled water diversifies the water supply options for the CCSD, and also provides a level of ‘drought-proofing’ towards the community’s investments in landscaping. Approximately 184 acre-feet per year in irrigation demands were identified for possible service with highly treated wastewater effluent. These demands would be limited primarily to the larger landscaped areas such as the proposed community park, the Santa Lucia Middle School, the Cambria Pines Lodge, the Cambria Nursery, and the new grammar school. Of these potential uses, approximately 99 acre-feet appear to be likely candidates for recycled water due to their proximity to a proposed distribution pipeline.”
6 Task 3, Final Draft Recycled Water Distribution Plan, Section 2, p. 6:
“Residential customers were not included in the estimate for recycled water due to their relatively low demand when compared with the high cost to install distribution piping. Additionally, the use of recycled water on residential customers creates a risk of cross connection with the potable water system.”
7 “Simultaneous Commercial and Residential Fires During Maximum Day Demand: These conditions represent two alternative levels (2,500 gpm and 3,500 gpm) of residential fire protection combined with simultaneous commercial fire protection 4,500 gpm). It is this criteria [sic] which presents the driver for improvements.” (Section 6, Recommended Water System Improvements, p. 43)
8 “Based on the hydraulic analyses described in Section 5, no pipeline improvements are necessary to meet future peak hour demands. Accordingly, there are no capital costs necessary to provide this level of service. The increases to distribution system pipelines are directly associated with increased fire flows. Initially, these costs were on the order of $16 to 20 million dollars in order to provide a residential fire flow of 3,500 gpm and commercial fire flow of 4,500 gpm. From review of the uniform fire code, and further review of actual structures using the District’s GIS system, it was found that the commercial fire flow of 3.500 gpm with a three-hour duration could be applied. Similarly, the residential fire flow could be reduced to 2,500 gpm and two-hour duration. Typically, residential areas are designed for approximately 1,000 to 1,500 gpm fire flow. It is suspected that this similar sizing assumption was applied to the CCSD service area based on the number of 6-inch pipes in the system. However, due to the high fuel loads and close proximity of the residences in these areas, a mid-range value of 2,500 gpm was targeted for the residential areas.” Section 6, Recommended Water System Improvements, p.47
9 “Furthermore, it was determined that the basins are not adequate to provide a 90 percent or 95 percent level of reliability for water demands greater than 10 percent of the 1999 demands (4,176 connections). Thus, the basins cannot reliably meet the increased demands of the waiting list and grandfathered connections (4,650 connections) without an additional source of recharge. A total of 286 AF of groundwater from the San Simeon Basin and 201 AF from the Santa Rosa Basin would be available with a 93 percent reliability during the dry season for a multi-dry year without causing adverse environmental impacts to the basins as determined by the model using the assumptions previously stated. However, since the Baseline report was completed in 2000, operation of well SR-4 has been minimal during the dry season due to concerns over potential habitat impacts. For this reason, dry season production is only assumed to be available from the San Simeon aquifer, and limited to approximately 286 acre ft. Table 2-2 provides an estimate of the supply availability based on the SWRCB diversion permits, the CCC Development permit, and negligible use of the Santa Rosa aquifer during the dry season. (Task 4, Section 2, p.12)
10 In the remaining 5 percent of the time, it is assumed that the maximum allowable supply shortage will be 5 percent of the demand. This level is recommended because a 5 percent water demand reduction was anticipated to be attainable in CCSD’s service area by voluntary conservation. Typically when a shortage occurs, water customers increase their awareness of water usage and voluntarily reduce water demands, avoiding water rationing. However with CCSD’s service area, customers are already actively conserving water. Thus the potential to cut additional demand via conservation practices is small. However, if improvements are made to the current demand management practices, as discussed in Section 8.7, additional reduction in potable water demand may be obtained. If a further reduction in water demand can be obtained through voluntary conservation, then the reliability criteria for CCSD’s water supply can be lowered by that amount. (Task 4, Section 2, p. 19)
11 The District has also started an aggressive meter replacement program to reduce the unaccountable water. The District has historically averaged 10 to 15 percent of unaccountable water per year when comparing billed versus production totals. Much of this may be due to under-reporting by existing meters. In 2004 the District completed a pilot study for automatic-remote-read meters, and installed 133 replacement meters with this new technology. Approximately 3,800 replacement meters have been installed within the District since this time. (Urban Water Management plan, p.2-10)
Last 5 posts by Elizabeth Bettenhausen
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