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Southern Willamette Valley Groundwater Management Area
The GWMA Action Plan serves to guide activities aimed at reducing nitrate contamination in the area's groundwater.
The complete Action Plan is 90 pages with a considerable number of pages containing either color photos or diagrams. You can download the PDF file (3.6 MB) to view, print, or save to your computer for future use.
At the May 25, 2006 meeting, the GWMA Committee reviewed a draft of the Action Plan compiled by Lane Council of Governments and made recommendations for final revisions. The Action Plan is based upon recommendations from the four working groups that had been previously approved by the GWMA Committee. These working group reports are on their respective web pages: Agricultural, Commercial/Industrial, Public Drinking Water & Residential. The Public Review version of the Action Plan was completed by Lane Council of Governments in August 2006.
D.E.Q. and other groups will hosted several meetings in October 2006 where the public could earn about the GWMA Action Plan, have their well water screened for nitrate, and submit written or oral comments for the record. Public comments were accepted until November 7, 2006.
A GWMA Committee meeting was held November 9, 2006 in Harrisburg. At that meeting, the committee reviewed the public comments and recommended a few changes to the Draft GWMA Action Plan. GWMA staff ware instructed to make the recommended minor changes and then forward the document to DEQ for their approval. DEQ staff approved the Action Plan as submitted in December 2006.
The Action Plan addendum (draft) serves as an update to the 2006 Action Plan. The addendum documents activities that have been implemented in the GWMA and may influence future planning and implementation activities.
The Oregon Groundwater Quality Protection Act says that if widespread groundwater contamination is believed to have resulted from non-point source pollution, DEQ must take certain steps to assist the community in reducing this contamination. These steps included:
Non-point source pollution comes from many individual activities rather than a single point such as a factory. Farms, forests, gardens, and city streets all contribute non-point source pollution.
According to the law, DEQ must declare a Groundwater Management Area (GWMA) if it is confirmed that the groundwater contains nitrate at 7 ppm (parts per million) as a result of non-point source pollution.
Once a Groundwater Management Area has been announced, DEQ must establish a local GWMA committee made up of affected citizens and other interested parties. The committee advises state agencies who are required to develop and implement an action plan that will reduce groundwater contamination in the area.
There are currently two other GWMAs in Oregon: One in the Hermiston area and one in the Ontario area.
Nitrate is a common contaminant of shallow groundwater in areas with well-drained soils. It comes from fertilizers, septic systems, and animal manure. The US EPA has set 10 ppm (parts per million) as the maximum allowable level of nitrate in water delivered by public drinking water systems. There are no requirements for individual private wells.
Nitrate concentrations above the accepted background level of 2 ppm have been recorded in the Southern Willamette Valley since the 1930s, with level above 10 ppm not uncommon.
These elevated levels of nitrate in groundwater prompted scientists from DEQ and Oregon State University to take a closer look at the connections between groundwater and activities that may be causing widespread contamination from nitrate. (Research page for reports).
In 2000, to determine if there was a need to declare a groundwater management area, DEQ identified a groundwater study area that included all of the valley floor between Eugene and Albany.
DEQ staff sampled about 500 wells from Fall 2000 through Summer 2001. Of these, 100 had nitrate levels at or above 7 ppm. Most of those 100 wells were resampled during Summer 2002, with additional test done for pesticides and bacteria.
Generally, the nitrate levels were similar the second year. Pesticides were found at very low levels.
The federal drinking water standard of 10 ppm of nitrate in drinking water was set half a century ago because there was evidence that a rare type of blue-baby syndrome called methemoglobinemia was associated with high levels of nitrate in drinking water. Since that time, a considerable amount of research has been done looking at health effects from drinking water with nitrate. Unfortunately, the evidence is mixed and no clear conclusions can be drawn at this time. The methemaglobinemia connection is being questioned and new conditions associated with high levels of nitrate are being suggested. Some evidence suggest that there may be adverse health effects from consuming water with nitrate below 10 ppm, other studies conclude that the 10 ppm standard is overly protective.