Em4885 irrigation management practices to protect ground water

Standards for ground water quality
FIGURE 2-9. Major Sources of Impairment for Lakes
13
CHAPTER 2
Standards for ground water quality in Washington State are set by WAC 173-200. It includes a
table of contaminant criteria for primary and secondary contaminants, radionuclides, and carcinogens.
In addition, it explains the enforcement limit as the “. . . value assigned to any contaminant for the
purposes of regulating that contaminant to protect existing ground water quality and to prevent
ground water pollution.” Enforcement limits are to be met at the “point of compliance,” the place
where the enforcement limit shall be measured and not exceeded. Enforcement limits are set based
on a number of considerations. Four of the nine listed are:
1. The anti-degradation policy of Washington State.
2. Overall protection of human health and the environment.
3. Protection of existing and future uses.
Major Sources of Impa
for Lakes
21%
15%
13%
11%
Agriculture
Urban Runoff
Natural Condi
Septic System
0 100
Percent of Assessed Si
4. “Any other considerations the department [Department of Ecology]
deems pertinent to achieve the objectives of this chapter.”
The Chapter discusses “early warning values.” The purpose of an early warning value is to
“provide early detection of increasing contaminant concentrations that may approach or exceed
enforcement limits.” If a contaminant is detected at the point of compliance and exceeds the early
warning value, a permit holder or other responsible person must notify Ecology within 10 days of
the detection.
The Chapter provides that a ground water quality evaluation program will be required when
Ecology determines that an activity has the potential to pollute. An approved evaluation program
will have the ability to assess impacts on ground water at the point of compliance.