UWM Plan - Municipal Water District of Orange County

Section 3
Water Sources and Supply Reliability
biological opinion for the salmon and other fish species that spawn in rivers flowing into
the Bay-Delta. The NFWS released its new biological opinion for salmonoid species on
June 4, 2009. DWR estimated an average 10 percent water loss from the Bay-Delta,
expected to begin in 2010, under this biological opinion. The impact on SWP deliveries
attributable to the Delta smelt and salmonoid species biological opinions combined is
estimated to be 1.0 MAF in an average year, reducing SWP deliveries from
approximately 2.3 MAF for the year under average hydrology.
DWR has altered the SWP operations to accommodate species of fish listed under the
ESAs, and these changes have adversely impacted SWP deliveries. DWR’s Water
Allocation Analysis indicated that export restrictions could reduce deliveries to
Metropolitan by 150 TAF to 200 TAF for 2010 under median hydrologic conditions.
Operational constraints likely will continue until a long-term solution to the problems in
the Bay-Delta is identified and implemented. New biological opinions for listed species
under the Federal ESA or by the California Department of Fish and Game’s issuance of
incidental take authorizations under the Federal ESA and California ESA might further
adversely affect SWP and CVP operations. Additionally, new litigation, listings of
additional species or new regulatory requirements could further adversely affect SWP
operations in the future by requiring additional export reductions, releases of additional
water from storage or other operational changes impacting water supply operations.
Current Conditions on SWP
The December 2009 draft of DWR’s SWP Delivery Reliability Report shows that future
SWP deliveries will be impacted by two significant factors: restrictions on SWP and CVP
Delta pumping and climate change. The 2009 draft Reliability Report shows greater
reductions in water deliveries on average when compared to the 2007 report. Over
multiple-year dry periods, average annual “Table A” 9 deliveries vary from 32% to 34%
of the maximum “Table A” amount, while average annual deliveries over multiple-year
wet periods range from 72 to 94 percent of the maximum Table A amount. Under future
conditions, annual SWP Article 21 deliveries average 62 TAF, ranging from 1 TAF to
550 TAF over the 82-year simulation period. The current “Table A” allocation as of
April 25, 2011 is 80 percent of the maximum “Table A” allotment.
9 9 The term “Table A” refers to Table A in the contract between each of the 29 State Water Contractors
and the California Department of Water Resources. Each Contractor’s “Table A” amount represents a share
of the project (the total amount of Table A for all contractors equals approximately 4.2M acre-feet) which
entitles each contractor to a portion of the available water supply for a given year and also obligates each
contractor to a share of the operations and debt financial obligations for the State Water Project.
Municipal Water District of Orange County
2010 Regional Urban Water Management Plan
Final
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