Quarterly Water Supply Strategy and Budget
Report
California-American Water Company Water
Distribution System: January - March 2004
December
15, 2003
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 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: January - March 2004
On
December 3, 2003, staff from the District, Cal-Am, California Department of
Fish and Game (CDFG), and the National Marine Fisheries Service (NOAA
Fisheries) discussed the proposed water supply strategy and related topics for
the remainder of December 2003 and the January-March 2004 period. Currently, total storage in Los Padres
Reservoir is 459 acre-feet (AF), Carmel River flow is less than 20 cubic feet
per second (cfs) at the MPWMD gaging station at Don Juan Bridge in Garland
Park, and there is no flow in the Carmel River below river mile 5.5.
Given
these “below-normal” conditions, it was agreed that Cal-Am would maintain a
daily diversion rate of 0.5 cfs from its wells in the Upper Carmel Valley. It was also agreed that Cal-Am would not
divert water from its San Clemente Reservoir during this period due to water
quality and operational constraints related to the San Clemente Reservoir
Drawdown Project required by the Department of Water Resources (DWR). For the Seaside Basin, it was agreed that
Cal-Am would reduce its pumping to 150 acre-feet (AF) in January and not pump
in February and March. In addition,
during January, Cal-Am will shift its production from wells that draw water
from the deeper Santa Margarita aquifer to wells that draw water from the
shallower Paso Robles aquifer. The
remainder of the water needed to serve Cal-Am customers and provide water to
the District’s Injection/Recovery Project in the Seaside Basin 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 February and March to 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 75 cfs in January, 105 cfs in
February and 116 cfs in March. 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-November 2003
period, it was agreed that the projections for the upcoming quarter should be
based on the assumption that inflows will be below-normal during the budgeted
January through March 2004 period.
Based on this assumption, District staff projected monthly unimpaired
inflows at San Clemente Dam of 1,510, 4,580, 6,020 and 7,120 AF for the months
of December 2003, and January, February, and March 2004, respectively. These monthly inflows are the 62.5%
exceedence flow values for the 1902-2003 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 December 2003-March
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 70% 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 December 3, 2003 meeting,
that Cal-Am’s November 4, 2003 request for an additional 90 days to respond to
DWR’s October 9, 2003 directive to (1) maintain the water level in San Clemente
Reservoir at a maximum elevation of 514 feet year round until further notice
and (2) submit a plan and schedule by November 10, 2003, to maintain the water
level at a maximum elevation of 505 feet year round by November 1, 2004, was
approved. Accordingly, Cal-Am can operate San Clemente Dam as described in the Amended
Project Description for San Clemente Reservoir Drawdown, 2003 and 2004
Operations, through February 2, 2004.
At that time, Cal-Am would be required to maintain the water level in
San Clemente Reservoir at a maximum elevation of 514 feet. Prior to that time, Cal-Am and other members
of the Drawdown Decision Group, i.e., DWR’s Division of Safety of Dams (DSOD),
NOAA Fisheries, United States Fish and Wildlife Service (USFWS), and CDFG, may
decide to allow San Clemente Reservoir to refill based on predetermined
criteria specified in Section 7.2 of the Amended Project Description. It is staff’s understanding that the
Drawdown Decision Group is scheduled to meet on December 8, 2003, to review the
refilling criteria. This decision will
be complicated by the fact that the sediment delta in the Carmel River
inundation area of San Clemente Reservoir has advanced to within 50 feet of the
newly-installed drawdown ports in the dam.
If this advance continues, there is a danger that the new drawdown ports
at elevation 514.5 feet will become clogged with debris, sediment, or both.
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