|
River Islands Development at Lathrop January 2021
<br /> Final River Islands Potable Water Technical Report-Rev 3 #6520
<br /> 4.2.2 Potable Water Supply-South San Joaquin Irrigation District/South County Water Supply
<br /> Program
<br /> The City purchases imported surface water from SSJID through the South County Water Supply Program
<br /> (SCWSP) which supplies treated Stanislaus River Water. The SCWSP is planned to be implemented in
<br /> two phases. Phase 1 was completed in 2005 and the improvements provided a total SCWSP capacity of
<br /> 31,500 acre-ft per year (AFV), of which 8,007 AFV is allocated to the City of Lathrop. The Phase 2
<br /> improvements will increase the total SCWSP capacity to 43,000 AFV, of which 11,791 AFV is allocated to
<br /> the City of Lathrop. Implementation of the Phase 2 improvements is unknown at this time (Water Master
<br /> Plan). In 2013, the City sold 1,120 AFY of SCWSP water to the City of Tracy (Water Master Plan).
<br /> Therefore, the City's remaining SSJID allocation is 6,887 AFV for Phase 1 and a total of 10,671 AFV after
<br /> completion of Phase 2. The SCWSP allows for seasonal increased flows based on peaking factors
<br /> determined by each City,which equates to 2.1 and 2.0 for Phase 1 and 2 respectively for the City of Lathrop
<br /> (Section 5.2.1 from 2002 SCWSP BODR). The remaining peak flow shall be 14,462 AFV and 21,342 AFV
<br /> for Phase 1 and 2 respectively.
<br /> Table 4-1: City of Lathrop-Allocated SCWSP Potable Water from SSJID
<br /> City of Lathrop Phase 1 Phase 2
<br /> SCWSP Design Flows (AFY) (MGD) (GPM) (AFY) (MGD) (GPM)
<br /> Contractual Allocation' 8,007 7.1 4,964 11,791 10.5 7,310
<br /> Sale to City of Tracy2 -1,120 -1.0 -694 -1,120 -1.0 -694
<br /> Remaining Allocation 6,887 6.1 4,270 10,671 9.5 6,616
<br /> -Peaking Factors3 2.1 2.0
<br /> Remaining Peak Flow Allocation 14,462 12.9 8,967 21,342 19.1 13,232
<br /> Notes
<br /> 1. From Table 5-1 in the 2002 South County Water Supply Program Basis of Design Report
<br /> 2. Per Section 5 of the City's Master Plan,the City sold 1,120 AFY of its Phase 1 SCWSP allocated flows to the
<br /> City of Tracy in 2013.
<br /> 3. The SCWSP allows for seasonal increased flows based on peaking factors determined by each City, which
<br /> equates to 2.1 and 2.0 for Phase 1 and 2 respectively for the City of Lathrop(Section 5.2.1 from 2002 SCWSP
<br /> BODR)
<br /> Purchased water from the SCWSP is currently delivered to the existing SSJID Turnout #1, located at the
<br /> eastern edge of the City along Lathrop Road. Turnout #1 was designed to provide a maximum flow of
<br /> 8,401 AFV (7.5 MGD) under both Phase 1 and 2 of the SCWSP. The proposed SSJID Turnout #2 is
<br /> currently under construction and will be adjacent to Phase 1 BPS and Storage Site. Flow from SSJID
<br /> Turnout#2 will feed the Phase 1 BPS and Storage site which will serve as the primary source of pressure
<br /> for River Islands. According to the City's Master Plan, the planned operating capacity of the proposed
<br /> Turnout#2 will be designed to supply the remaining of the allocated SCWSP flows,after Turnout#1 reaches
<br /> its capacity of 8,401 AFV (7.5 MGD) per year. Under the peak flows listed in Table 4-1, the planned
<br /> operating capacity of the proposed Turnout#2 for Phase 1 and 2 is approximately 6,061 AFV (5.1 MGD)
<br /> and 12,938 AFV(11.55 MGD) respectively.
<br /> Table 4-2: City of Lathrop- Design SSJID Turnout Capacities
<br /> City of Lathrop Phase 1 Phase 2
<br /> SCWSP Design Flows (AFY) (MGD) I (GPM) (AFY) (MGD) (GPM)
<br /> Remaining Peak Flow Allocation 14,462 12.9 8,967 21,342 19.1 13,232
<br /> SSJID Turnout#1 Design Capacity 8,401 7.5 5,209 8,401 7.5 5,209
<br /> SSJID Turnout#2 Design Capacity 6,604 5.4 3,758 12,941 11.6 8,023
<br /> 19
<br />
|