The Weiser Nitrate Priority Area: An Application of Idaho's Policy for Addressing Degraded Ground Water Quality Areas

摘要

A combination of water management practices, land uses, and hydro-geologic conditions have resulted in degraded ground water quality in certain areas of Idaho. A statewide ambient ground water quality monitoring program (statewide program) has been operated in Idaho since 1990. Nitrate was identified as one of the most prevalent contaminants of concern during the initial years of the statewide program. A combination of statewide, regional, local, and public water system monitoring data collected by various state and federal agencies, and private entities, enabled a consortium of water experts to delineate 25 “nitrate priority areas.” In 2000, the Director of the Idaho Department of Environmental Quality (IDEQ) released a policy describing a systematic approach for addressing the degraded ground water quality areas. The area receiving the highest-priority ranking in Idaho is known as the Weiser nitrate priority area. Sixty-five wells have been sampled routinely in the Weiser area; 72% indicate nitrate levels above 5 mg/l and 45% have been impacted above a level of 10 mg/l. IDEQ began implementing the Director’s degraded ground water policy in the Weiser area in October 2001 with the formation of a local stakeholder advisory committee. The committee has become educated on ground water quality issues and land use best management practices (BMPs) during the development of a ground water management plan. IDEQ and the advisory committee will use the ground water management plan as a guide to promote public education and voluntary implementation of BMPs, with regulatory controls being considered only as a final option.