Quarterly Water Supply Strategy and
Budget Report
California-American Water Company Water
Distribution System: April - June 2004
March
15, 2004
1. Management
Objectives
The
District desires to maximize the long-term production potential and protect the
environmental quality of the Carmel River and Seaside Ground Water Basins. In addition, the District desires to
maximize the amount of water that can be diverted from the Carmel River Basin
and injected into the Seaside Ground Water Basin while complying with the
instream flow requirements recommended by National Marine Fisheries Service
(NOAA-Fisheries) to protect the Carmel River steelhead population. To accomplish these goals, a water supply
strategy and budget for production within the California-American Water Company
(Cal-Am) water distribution system is reviewed quarterly to determine the
optimal strategy for operations, given the current hydrologic and system
conditions.
2. Quarterly
Water Supply Strategy: April - June 2004
On
March 3, 2004, staff from the District, Cal-Am, California Department of Fish
and Game (CDFG), and the NOAA-Fisheries discussed the proposed water supply
strategy and related topics for the remainder of March 2004 and the April-June
2004 period. Currently, Los Padres
Reservoir is full and spilling, Carmel River flow is more than 20 cubic feet
per second (cfs) at the MPWMD gaging station at Don Juan Bridge in Garland
Park, and there is approximately 300 cfs flow in the Carmel River below river
mile 5.5.
Given these “near normal” conditions, it was agreed that Cal-Am would maintain a daily diversion rate of 1.5 cfs from its wells in the Upper Carmel Valley. It was also agreed that if feasible, Cal-Am could divert water from its San Clemente Reservoir during this period. However, the feasibility of diverting water at San Clemente Dam will probably be constrained by water quality and operations related to the San Clemente Reservoir Drawdown Project mandated by the Department of Water Resources (DWR). For the Seaside Basin, it was agreed that Cal-Am would maintain zero pumping during the remainder of March and in April. During May, Cal-Am will shift a portion of its production back to the Seaside Basin, and specifically to wells that draw water from the shallower Paso Robles aquifer for the first three weeks and begin maximizing production from Seaside during the last two weeks of May. During June, it was assumed that Cal-Am would produce 550 AF from the Seaside Basin. The remainder of the water needed to serve Cal-Am customers during this quarter will be produced from Cal-Am’s wells in the Lower Carmel Valley. Cal-Am will operate its wells in the Lower Carmel Valley in a downstream to upstream sequence.
It is assumed that there will be sufficient flow in the Carmel River in March and April allow diversions to be made for the Seaside Injection/Recovery Project. The projected production values are based on the assumption that daily inflows in the upper watershed will average 125 cfs in April, 45 cfs in May, and 20 cfs in June. If actual inflows are more or less than projected, the group will reconvene and adjust the diversion and release rates accordingly. These adjustments will take into account flows needed for steelhead migration, spawning and egg incubation and Cal-Am’s operational needs.
Based
on the rainfall and runoff that occurred during the October-February 2004
period, it was agreed that the projections for the upcoming quarter should be
based on the assumption that inflows will be near-normal during the budgeted
April through June 2004 period. Based
on this assumption and recent rainfall, District staff projected
monthly-unimpaired inflows at San Clemente Dam of 7,294, 6,208 2,328 and 1,086
AF for the months of March, April, May and June 2004, respectively. These
monthly inflows are the 78 % of the expected median flow values for the
1902-1996 period of record. Table 1 shows a monthly breakdown of the
recommended diversion and release schedule under the projected inflow
conditions. Table 1 also shows
expected inflows, outflows, and storage volumes at Los Padres and San Clemente
Reservoirs for the April-June 2004 period.
It should be noted that there is significant uncertainty regarding the rainfall and runoff that will occur during the upcoming quarter, which accounts for almost 45% of the runoff expected during the year on average. This uncertainty is compounded by the situation at San Clemente Dam and Reservoir. It is staff’s understanding, based on information provided at the March 3, 2004 meeting and a recent letter from the Department of Water Resources, dated February 4, 2004, that Cal-Am will operate San Clemente Dam as follows:
1) The
reservoir may be allowed to remain full at the spillway elevation of 525 feet
from February 2, 2004 through April 15, 2004;
2) Drawdown of the reservoir from
elevation 525 to 515 feet will commence on or soon after April 15, pending
inflow conditions, and per the recently adopted San Clemente Dam 2004
Drawdown Project, Amended Project Description for Operations and Monitoring;
3) The reservoir may continue to be operated in a manner to not allow sediment from passing downstream through the ports or any other passage; and
4) A plan needs to be developed to restrict the reservoir after December 31, 2004, when the current Section 404 permit expires.
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