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Groundwater Management Areas

Groundwater Management Areas are designated by DEQ when groundwater in an area has elevated contaminant concentrations resulting, at least in part, from nonpoint sources. Once the GWMA is declared, a local groundwater management committee comprised of affected and interested parties is formed. The committee then works with and advises the state agencies that are required to develop an action plan that will reduce groundwater contamination in the area.


Oregon has designated three GWMAs because of elevated nitrate concentrations in groundwater. These include the Lower Umatilla Basin GWMA, the Northern Malheur County GWMA, and the Southern Willamette Valley GWMA. Each one has developed a voluntary action plan to reduce nitrate concentrations in groundwater. 

DEQ declared the Lower Umatilla Basin a Groundwater Management Area in 1990 because nitrate-nitrogen concentrations in many area groundwater samples exceed the federal safe drinking water standard. 

Learn more on our Nitrate Contamination: Lower Umatilla Basin, Northern Morrow and Umatilla Counties page.

​The Northern Malheur County Groundwater Management Area was declared in 1989 after widespread groundwater nitrate contamination was identified that had resulted primarily from nonpoint source activities. Oregon DEQ and a citizen’s advisory committee created an Action Plan for restoring the groundwater nitrate concentrations to acceptable levels. The Action Plan identifies specific "measures" to gauge the success of groundwater restoration activities in the area.

Action plan



​​​​The Southern Willamette Valley is one of Oregon’s fastest growing regions and depends heavily on groundwater for both private and public drinking water, irrigation water, and other uses. The Groundwater Management Area is the result of many years of studies and analyses of the shallow groundwater in the lowlands of the Southern Willamette Valley. Studies beginning in the 1990s show that shallow groundwater contains nitrate above levels that are a concern.

On May 10, 2004, following a public comment period on the final Southern Willamette Valley groundwater report and proposal for declaring a Groundwater Management Area, DEQ director Stephanie Hallock signed the official Declaration, creating the Southern Willamette Valley Groundwater Management Area. By declaring a Groundwater Management Area for portions of the Southern Willamette Valley, DEQ, Department of Agriculture, Water Resource Department, Department of Human Services and other state agencies are required to focus efforts on the development of an Action Plan to restore the groundwater quality.

Proposed Action Plan




Eastern Region
Randy Jones

Northwest Region

Western Region
Sara Sauter