Quarterly Water Supply Strategy and
Budget Report
California-American Water Company Water
Distribution System: April - June 2006
March
20, 2006
1. Management
Objectives
The
District desires to maximize the long-term production potential and protect the
environmental quality of the Carmel River and Seaside Groundwater 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 Groundwater Basin while complying with the instream flow
requirements recommended by the 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 (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 2006
On
March 7, 2006, staff from the District, Cal-Am and NOAA Fisheries discussed the
proposed water supply strategy and related topics for the remainder of March
2006 and the April-June 2006 period.
Currently, Los Padres Reservoir is full and spilling, Carmel River flow
is approximately 450 cubic feet per second (cfs) at the MPWMD gaging station at
Don Juan Bridge in Garland Park, and there is approximately 500 cfs flow in the
Carmel River below river mile 5.5.[1] Most of February had been dry, with inflows
ranging from 47 to 80 cfs at San Clemente Reservoir during the February 1-26
period. Subsequently, several storms
passed over Central California during the last three days of February and first
week of March and inflows increased substantially, with daily inflows ranging
from approximately 380 to 2,100 cfs.
Given
these conditions, it was agreed that for the remainder of March and in April
2006, Cal-Am's diversions from the upper Carmel Valley would be up to 4.0 cfs,
including combined production from the Russell Wells Nos. 2 and 4 and other
sources upstream of and including Scarlett Well No. 8. In May 2006, the proposed budget allows
Cal-Am to divert up to 2.1 cfs from its combined sources upstream of and
including Scarlett Well No. 8. During
June 2006, the proposed budget allows Cal-Am a net diversion of no more than
0.96 cfs or 57 AF from the Russell Wells Nos. 2 and 4. 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 California Department of Water
Resources (DWR). With the exception of the Upper Carmel Valley, Cal-Am will operate
its wells in the Lower Carmel Valley in a downstream to upstream sequence, as
needed to meet demand.
For
the Seaside Basin, it was agreed that in May and continuing through June 2006,
Cal-Am will gradually shift its production from the Carmel River Basin to wells
in the Seaside Basin, associated with anticipated declining rainfall and runoff
in the Carmel Basin. Accordingly, more of the water needed to serve Cal-Am
customers will be produced from the Seaside Basin as the dry season progresses. Specifically, in May, Cal-Am will draw water
from the shallower Paso Robles aquifer and other wells, except for the Paralta
Well with a production goal of 300 AF.
In June 2006, Cal-Am will bring on all of its Seaside wells with a goal
of 500 AF. 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 2006 to allow diversions
to be made for the Seaside ASR Project.
The projected production values are based on the assumption that daily
inflows in the upper watershed will average 98 cfs in April, 44 cfs in May, and
17 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 2005 through February
2006 period, it was agreed that the projections for the upcoming quarter should
be based on the assumption that inflows will approximate normal monthly levels
during the budgeted April through June 2006 period. Based on this assumption and recent rainfall,
District staff projected monthly unimpaired inflows at the San Clemente Dam
site of 11,250, 5,953, 2,829 and 1,057 AF for the months of March, April, May
and June 2006, respectively. These monthly inflows equal the 50% (median)
expected flow values for the 1902-2005 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 2006 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. Based on a verbal description of the Biological Opinion for the Interim San Clemente Reservoir Drawdown Project by NOAA Fisheries, staff understands that Cal-Am will operate San Clemente Dam in Spring 2006 as follows:
1) The
reservoir will remain full at the spillway elevation of 525 feet through May
31, 2006.
2) Drawdown of the reservoir from
elevation 525 feet to 515 feet will commence on June 1, 2006, subject to the
maximum capacity of the outlet works at San Clemente Dam.
3) During the drawdown period beginning June 1, 2006, the reservoir releases may be modified, depending on the physical ability to release water while minimizing the amount sediment passing downstream through the ports or any other passage.
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