PUB00050

• Year: 1997
• Title: Layperson's Guide to Water Conservation
• CWCB Section: Water Conservation & Drought Planning
• Author: California Water Education Foundation
• Description: Layperson's Guide to Water Conservation
• Publications - Doc Type: Other

measure the volume of water delivered to individual
water users. Accurate water use data are consid-
ered critical to the design and operation of effective
water management plans.

As with the urban suppliers' MOU (see page 14).
the agricultural MOU is not universally endorsed. and
agricultural interests have questioned practices
aimed at enhancing planning and water measure-
ment. Critics say neither of these is likely to result in
net water savings and may even negate some
existing water efficient management practices. The
water measurement component is viewed suspi-
ciously by some as a first step toward tiered water
pricing, and they are reluctantly going along
with the MOU as a means of
demonstrating that they are
concerned about efficient
water use.

EWMPs

Although it includes mandatory elements.
the bulk of the agricultural MOU consists of
optional EWMPs such as facilitating volun-
tary water transfers and financing capital
improvements for on-farm irrigation systems.
Water districts representing more than 2
million acres of irrigated farmland signed the
MOU in early 1997, enough to trigger the
EWMPs and call for formation of an Agricul-
tural Water Management Council to oversee
MOU implementation. Irrigation districts that
sign the MOU commit to six core actions that
are not subject to cost/benefit analysis.
Those actions are:

Designation of a water conservation
coordinator by the agency;

Preparation and adoption of a water
management plan;

Support for the availability of water
management services to water users;

. Improvements in communication and
cooperative work among agricultural
water suppliers, water users, and other
agencies;

. Evaluation of possible changes in policies
of institutions to which the water supplier
is subject;

Evaluation and improvement of efficien-
cies of water suppliers' pumps.

10

Water districts that contract with
the Bureau to supply water to
farmers are now required by
the CVPIA to prepare water
management plans and update
those plans every five years.
The criteria the Bureau uses
to evaluate those plans incor-
porate BMPs, which include
many of the EWMPs. Each
district's plan is required to
include a description of the
water district, an inventory of its
water resources and uses of
those resources, and a list of
BMPs the district will follow to
ensure efficient water use. For
contractors that supply agricul-
tural users, the critical BMPs
include use of equipment to
measure the volume of water
delivered, adoption of a pricing
structure based at least in part
on the quantity of water deliv-
ered, designation of staff to
implement the water manage-
ment plan, and provision of
water management services for
farmers in the forms of data,
educational programs, and on-
farm water use evaluations.

Water management plans de-
veloped under the CVPIA may
be incorporated into EWMPs.
but such plans are not recog-

nized automatically as the equivalent of EWMPs. The
Agricultural Water Management Council reviews
each district's plan on a case-by-case basis. Provi-
sions of water conservation plans developed under
the CVPIA criteria will be accepted if they meet
provisions of the MOU.

Some water districts serving agricultural areas have
developed extensive water conservation programs
to help their customers. One of the largest. the 1,000-
square-mile Westlands Water District, has its own
water conservation coordinator and a water manage-
ment specialist who provide practical information and
technical assistance to farmers on a variety of water
conservation topics specific to local conditions.

Irrigation water losses are classified as either
recoverable or irrecoverable. Recoverable losses
may include seepage, leakage and spillage during
storage and conveyance, and surface runoff and
deep percolation during irrigation. Irrecoverable
losses include evaporation from water and soil
surfaces, transpiration from plant leaves into the
atmosphere, and return flows to saline groundwater
and surface water that are not available for reuse.

Much of the water used in irrigation is classified as
recoverable and can be reused. although its quality
may be impaired for some uses. Seepage and deep
percolation from irrigated fields are potentially re-
coverable when water percolates below the plant
roots and becomes part of the groundwater supply.

Conservation efforts that reduce recoverable losses
may reduce the amount of water an individual farmer
must buy or pump. but they do not necessarily
provide a net savings of water use to the region or
to the state. Only by reducing the amount of water
that is irrecoverably lost to the atmosphere. saline
groundwater or to the ocean, will the state's usable
water supply be increased. Evapotranspiration -
evaporation from water and soil surfaces and
transpiration from plant leaves into the atmosphere
- is the major cause of irrecoverable water loss.
Water savings could occur if farmers include more
fallow land in their crop rotations or switch to crops
that have shorter growing seasons and transpire less
water. However, farmers say crop choices are
dictated by market demands for commodities, not
by evapotranspiration rates.

A farmer's choice of irrigation methods is determined
primarily by three factors: the type of soil to be