Em4885 irrigation management practices to protect ground water

2 CHAPTER
Complaints of water pollution from agricultural activities are presently being managed
under a Compliance Memorandum of Agreement between the Washington Department of Ecology
(Ecology), local conservation districts, and the Washington State Conservation Commission. The
local conservation district disseminates information developed as a result of nonpoint source pollution
planning. In the case of a water pollution complaint, Ecology first investigates the complaint. If a
pollution problem is verified, the farm is required to correct the problem. The local conservation
district is available to provide assistance to the farm to develop a conservation plan and address the
problem source. This is currently occurring with dairy farms and may become more common on
irrigated farms if contamination of water from irrigated agriculture is seen as a problem.
Assessment of Water Quality
A 1987 amendment to the 1972 Federal Clean Water Act required all states to assess water quality
and develop a program for nonpoint source pollution. Ecology is responsible for carrying out this
mandate in Washington. It published the Nonpoint Source Pollution Assessment and Management
Program in October 1989 (1989 Management Program).
The 1989 Management Program reported the results of Ecology’s assessment of water quality in
the state as well as the developed management program. The assessment program included:
1. Identifying and characterizing waterbodies of the state - The surface waterbodies are defined
as coastal waters, estuaries, rivers, lakes, or wetlands. These waterbodies may be classified
as Class AA, Class A, Class B, Class C, or Lake depending on the number and type of
beneficial uses supported. Table 2-1, taken from the Assessment and Management Program
document, lists the beneficial uses and shows how the Class designation declines as the
number and type of beneficial uses become restricted.
2. Identifying the beneficial uses associated with waterbodies - Beneficial uses include domestic
and livestock water supplies, industrial uses, irrigation, fish habitat, wildlife habitat,
recreation, and navigation.
3. Developing water quality standards to protect beneficial uses - Numerical water quality
criteria are needed to provide benchmarks for protection. As water quality test results
approach or exceed the standards, regulations may force certain actions to alleviate the
contaminating activity. Table 2-2, also taken from the Assessment and Management
Program document, is a summary of numerical water quality criteria for the various
parameters used to define a waterbody class. Note that as the amount of bacteria,
temperature, pH, and turbidity goes up, and as the amount of dissolved oxygen goes
down, the waterbody rating goes down.
4. Testing for exceedance of water quality standards.
Ecology now gathers all available information concerning water quality in the state and reports
it every two years. The latest report was 1992 Statewide Water Quality Assessment
(1992 Assessment).
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