California Drought: Water Supply and Conveyance Issues

California Drought: Water Supply and Conveyance Issues

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Updated February 28, 2017
California Drought: Water Supply and Conveyance Issues
Overview
Unlike many other states, California has a vast water-
Despite recent rain, snowstorms, and severe flooding,
supply system composed of the State Water Project (SWP)
portions of California—primarily the south-central coast
and the federal Central Valley Project (CVP). Both projects
and Southern California—continue to experience moderate
supply water to irrigation and water districts throughout
to severe drought. (See Figure 1.) Compared to a year ago,
much of the state. The SWP primarily provides water to
however, statewide conditions have improved greatly. The
municipal and industrial (M&I) users and some agricultural
2015-2016 winter was the driest since recordkeeping began
users. The SWP announced an increase in water deliveries
in the 1950s, but the 2016-2017 winter is shaping up to be
for 2017 over 2016, but deliveries remain curtailed (60% of
one of the wettest. Although recent months have brought
contracted supply), as of January 18, 2017.
intense precipitation, more may be needed to replenish
groundwater supplies depleted by five years of drought.
The CVP supplies water to hundreds of thousands of acres
Ongoing drought conditions in California are of continued
of agricultural land throughout the state, as well as to some
interest to Congress.
wildlife refuges and M&I water users. In 2015, water
deliveries to some entities with CVP water contracts were
Despite the recent precipitation and even flooding in some
cut by 100% (i.e., the users received no CVP water). For
areas, some portions of California may be entering a sixth
senior water rights contractors, CVP supplies were reduced
year of drought; water deliveries to municipal water and
by 25% in 2015. In 2016, the Department of the Interior’s
irrigation districts from federal and state water projects may
Bureau of Reclamation cut back water deliveries to some
still be curtailed. It is not clear if, or by how much, above-
CVP water users. Water deliveries for many CVP
normal precipitation in 2017 will ease drought conditions in
contractors were announced at 100% on February 28, 2017;
remaining dry areas or how water supply will be affected.
however, allocations for some water service contractors
have not yet been announced.
A drought declaration made by the governor on January 17,
Congress funds and oversees the Central Valley
2014, remains in effect, as do statewide water conservation
Project, which in a “normal” water year delivers an
measures.
average of approximately 7 million acre-feet of
Figure 1. California Drought: Feb. 2017 and Feb. 2016
water—an estimated 20% of California surface water
withdrawals.
Major CVP and SWP pumps that move water to Central
and Southern California are located at the southern portion
of the Sacramento and San Joaquin Rivers’ Delta
confluence with the San Francisco Bay (Bay-Delta).
Approximately 22 million people receive water from the
Bay-Delta annually. Curtailed operation of the pumps and
the CVP water deliveries have been the subject of much
congressional debate; Congress directed increased
flexibility in pumping levels in the Water Infrastructure
Improvements for the Nation (WIIN) Act (P.L. 114-322,
Subtitle J), enacted in December 2016.
What’s at Stake?
Drought conditions in California over the past five to six
years, combined with restrictions on CVP and SWP
operations to protect water quality, fish, and wildlife,
affected several sectors and areas. Many cities and counties
instituted water rationing, some fish and bird populations
Source: U.S. Drought Monitor at http://droughtmonitor.unl.edu/
declined, and the governor mandated a 25% cutback in
Home/StateDroughtMonitor.aspx?CA.
nonagricultural water use statewide.
U.S. Department of Agriculture secretarial drought
California agriculture remains the nation’s largest producer
designations also remain in place for approximately two-
in terms of cash farm receipts—accounting for 12.5% ($47
thirds of the state (24 primary and 8 contiguous counties),
billion) of the U.S. total in 2015, the last year for which
as of February 22, 2017. Such federal declarations make
data are available. Although California’s 2015 receipts were
available emergency loans, which partially compensate for
down 17% from 2014, producers with access to
losses for producers who cannot obtain commercial credit.
groundwater or other water supplies saw receipts grow
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California Drought: Water Supply and Conveyance Issues
despite the drought, and some even expanded production.
Figure 2. Major California Reservoir Levels
Others had to fallow land or uproot orchards and vines due
to drought. Some livestock producers had to purchase
supplemental hay and grain.
Low water supplies could have ramifications beyond the
state, resulting in higher product prices for some
commodities—particularly those for which California is the
primary producer (e.g., almonds). California produces 65%
of the nation’s noncitrus fruit and nuts. However, where
crop substitutes exist, or where the crops can be grown
elsewhere, prices may not be immediately affected.
Some cities’ and farms’ access to groundwater or
transferred surface water helped some users adjust to dry
conditions. However, even with improved drought
conditions and surface water storage, low groundwater
levels and land subsidence due to groundwater pumping
during the last five years of drought may persist. California
has enacted a statewide law that will increase groundwater
planning and monitoring, but implementation will take
many years.
Long-term drought also affects electric power production,
recreation, air quality, and fish and wildlife. For example,
some salmon runs experienced a 95% loss of eggs laid in
2015, and a June 2016 survey of Delta smelt found 13 adult

smelt, the lowest catch in the history of the survey (the total
Source: California Data Exchange Center, Selected Reservoirs Daily
population is estimated at 13,000—a record low), according
Graphs—Water Supply, at http://cdec.water.ca.gov/reservoir.html.
to the U.S. Fish and Wildlife Service. Although recent rains
Note: The red lines indicate percentage of historical average for the
and projected runoff may improve conditions for salmon
same time of year, whereas the blue bars represent percentage of
and smelt, poor ocean conditions in 2015 and 2016 will
total reservoir capacity.
affect adult returns for coho and Chinook salmon; thus,
2017 returns remain uncertain. Preseason projections for
Regulatory Factors and
2017 salmon returns will be available in the spring.
Congressional Activity
Storage and Hydrologic Status
Water project operations and deliveries are determined not
only by hydrologic and storage conditions but also by state
In early 2017, water levels at most of California’s largest
and federal regulatory requirements on CVP and SWP
reservoirs are well above their historic averages. (See
operations. These requirements affect how much water is
Figure 2.) The water content of snow in the Sierra Nevada
delivered from the projects. State water rights priorities and
Mountains is also well above average. Snowpack is a major
Reclamation contracts also affect water allocation. Many
part of water storage for the state.
water users have called for modifying regulations to allow
for more water transport and deliveries; some fishermen
Snowpack in the Northern Sierra/Trinity Mountains is
and environmental groups believe such changes may risk
161% of normal for this time of year. Snowpack in the
extinction of species.
central and southern Sierra Mountains is 193% and 204%
of normal for this time of year, respectively. A major
The 114th Congress addressed CVP and SWP project
question for water supply moving into the spring and
operations in Subtitle J of P.L. 114-322 by adding some
summer months is when and how rapidly snow melt and
flexibility in project operations. (See CRS In Focus
runoff might begin. A warming trend could force reservoir
IF10536, Water Infrastructure Improvements for the Nation
managers to release water from reservoirs to allow space
Act (WIIN), by Nicole T. Carter et al.) Additional
for incoming runoff. If storms upon which these decisions
legislation to provide more water to water users has been
are based fail to materialize, or if runoff is less than
introduced in the 115th Congress (e.g., H.R. 23). Oversight
projected, the result may be less water in reservoir storage
of how the Trump Administration implements P.L. 114-322
for coming dry months. How to balance competing
is also likely in the 115th Congress.
reservoir storage space for water supply versus flood
storage is a major challenge for both state and federal
reservoir operators.
Charles V. Stern, Acting Section Research Manager
IF10133

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California Drought: Water Supply and Conveyance Issues

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