Monterey Peninsula Water Management District (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
(NMFS) to protect the Carmel
population. Similarly, during the
low-flow season, the District desires to recover some or all of the water that
was previously injected into the Seaside
as well as a seasonally balanced amount of California American Water’s (CAW) full
allocation of Seaside
native groundwater. By meeting customer
demand with as much as feasible of these two groundwater sources, CAW will be
able to maximally reduce its diversion from its Carmel River
sources during the low-flow season. To
accomplish these goals, a water supply strategy and budget for production
within the CAW Main and Laguna Seca Subarea
water distribution systems is reviewed quarterly to determine the optimal
strategy for operations, given the current hydrologic and system conditions.
Water Supply Strategy: October - December 2010
September 8, 2010, staff from the District, CAW, the California Department of
Fish and Game (CDFG), and National Marine Fisheries Service (NMFS) met and
discussed the proposed water supply strategy and related topics for the
remainder of September 2010 and the October through December 2010 period. Currently, flow in the Carmel River
is regulated by releases from storage at Los Padres Reservoir that are
supplementing natural base flow. The
intent under the CDFG/CAW/MPWMD Low Flow MOA is to sustain 12 cubic feet per
second (cfs) of flow to the Sleepy Hollow Weir at River Mile (RM) 17.64 through
December 2010. Flow in the Carmel River
is continuous from the headwaters almost to Highway 1, with approximately 2.3
cfs at the USGS Near Carmel Gage (RM 3.24) and 0.18 cfs at the MPWMD Highway 1
Gage (RM 1.00) on September 8, 2010.
Rainfall during WY 2010 to date through the end of August at San
Clemente Dam in the upper watershed has totaled 27.45 inches or 129% of the
long-term average at this site. Further,
unimpaired runoff at San Clemente Dam for Water Year 2010 to date through the
end of August has totaled approximately 97,802 AF or about 143% of the long-term
average for this site.
River Basin Given these conditions, it was agreed
that it would be appropriate to use a range of “extremely wet" to “normal”
inflow conditions to assess CAW’s operations during the October through
December 2010 period, with flows ramping down one level of water year type
during each month from September through December 2010. Thereafter, “normal” year inflows would be
used to conservatively assess CAW’s operations and set monthly production
targets for CAW’s systems from January through September 2011.
meet customer demand, CAW would operate its wells in the Lower Carmel
Valley in a
downstream-to-upstream sequence, as needed.
For the quarterly budget, it was agreed that CAW would produce
approximately 0 AF of groundwater each month from its wells in the Upper Carmel
Valley during October,
November, and December 2010. These
amounts are consistent with the interagency Low Flow Season MOA and CAW
management’s intent to minimize production in the Upper Carmel
Valley at all times.
In addition, it was agreed that CAW would
produce approximately 687, 447, and 446 AF of groundwater from its wells in the
Lower Carmel Valley
during October, November, and December 2010, respectively. Table 1 shows actual and projected
monthly releases and diversions from Los Padres and San Clemente Reservoirs for
the October 2009 through December 2010 period.
it was assumed that no water would be diverted from the Carmel
River Basin and injected into the Seaside Groundwater Basin
during this period, since the diversion season for ASR ended May 31, and does
not resume until December 1, 2010, if flows are sufficient to allow
diversions. The long-term average of 920
AF per Water Year of ASR diversions to storage are planned for the next quarter
of January to March, 2011. If the
minimum bypass flows defined in the joint MPWMD/CAW Water Right for ASR Phase 1
are sufficient for any significant length of time after December 1, diversion
to storage may begin that month.
It was also agreed that in October and November 2010 the production goal
is to maximize the recovery of water stored in WY 2010 by ASR, with 496 AF then
480 AF to be recovered, respectively.
December’s production from the Coastal Subareas of the Seaside Groundwater
Basin would be comprised
of 270 AF of native groundwater, combined with 135 AF of storage recovered from
ASR. There is also a goal of producing an additional 25 AF of treated brackish
groundwater from the Sand City Desalination Plant in each of these three
months. The Sand City Desalination Plant
is still in the early phases of full production testing, therefore its monthly
yield may vary for the near term, and has averaged approximately 8 AF per month
since it went on line in April 2010. If
it cannot make its monthly production targets, the needed water will be
produced from a combination of ASR wells in Seaside and CAW wells in the Lower Subunits
of the Carmel Valley Aquifer.
was also agreed that CAW should produce only 24, 16, and 13 AF per month of
groundwater from its wells in the Laguna Seca Subarea of the Seaside Basin
for customers in the Ryan Ranch, Bishop, and Hidden Hills systems during
October, November, and December 2010, respectively. It is recognized that, based on recent
historical use, CAW’s actual production from the Laguna Seca Subarea during
this period will likely exceed the proposed monthly targets, which are based on
CAW’s allocation specified in the Seaside Basin Adjudication Decision. For
example, in the October, November, and December 2009 period, CAW produced 39,
36, and 26 AF from the Laguna Seca Subarea to meet customer demand in the Ryan
Ranch, Bishop, and Hidden Hills systems.
In this context, the production targets represent the maximum monthly
production that should occur so that CAW remains within its adjudicated
allocation for the Laguna Seca Subarea.
Under the amended Seaside Basin Decision, CAW is allowed to use
production savings in the Coastal Subareas to offset over-production in the
Laguna Seca Subarea, if any remains after maximizing production in order to
minimize pumping of the Carmel Valley Aquifer, in compliance with SWRCB Order
WR 95-10, and 2009-0060.
to the Quarterly Water Supply Strategy for July - September 2010
The State Water Resources Control Board
(SWRCB) sent a letter to CAW on August 5, 2010 (referenced as JWC:A011674A)
instructing CAW to maximize its use of Seaside Basin Native Groundwater each
Water Year and avoid carrying over any of that type of water into the next
Water Year, or be considered in violation of Condition 9 of Order WR 2009-0060
which refers specifically to Condition 4 of Order WR 95-10. Based on that letter, MPWMD staff took the
following actions to correct the accounting in the last four months of the
Water Year 2010 Budget for June – September to make it as compliant with the
SWRCB’s instructions as possible.
Instead of accounting for part of the water produced from the Seaside
Basin out of CAW’s coastal wells during these four months as being recovered
for ASR, all of the water produced from the Seaside Coastal Basin Groundwater
sources was accounted for as native groundwater, and recovery of the 1,111 AF
of WY 2010 ASR Phase 1 storage was reassigned to the first three months of WY
2011. This action maximizes the use of
Seaside Basin Native Groundwater in WY 2010, thereby minimizing the amount of
that water source that is being carried over into WY 2011 to 83 AF. Without such an adjustment, the amount of
Seaside Native Groundwater that would be allocated to carry over supplies would
be 459 AF higher, or a total of 542 AF.
These corrections to the Quarterly Water Budgets for the months of June
– September in WY 2010 were concurred with by CDFG and the NMFS, and will be
reported to the SWRCB by CAW.