The state of Oregon has designated a Groundwater Management Area (GWMA) in the southern Willamette Valley of Oregon because of high nitrate levels in many domestic wells. EPA ORD scientists have partnered with EPA Region 10, Oregon Department of Environmental Quality (DEQ), and other state and local groups to develop best management practices for agriculture within the area. The team has been working with local farmers to measure nitrate leaving their fields and to demonstrate how those levels change under different fertilization and crop management practices.
“EPA ORD scientists have made significant contributions to the monitoring program in the southern Willamette Valley Groundwater Management Area (GWMA). Their technical expertise has enhanced analyses of complex hydrological systems, as well as informed Oregon Department of Environmental Quality’s synthesis of multi-scale factors impacting nitrate concentrations in the southern Willamette Valley GWMA” said Oregon Department of Environmental Quality Acting Director Joni Hammond.
In addition, EPA ORD scientists have provided stable isotopic analyses to identify the causes of high temporal nutrient variability within local wells. These efforts have helped illuminate complex groundwater-surface water interactions, and greatly improved Oregon DEQ’s monitoring program for the GWMA. EPA ORD’s involvement has greatly improved efforts to both reduce potential new inputs of nitrate into the groundwater system, and to understand the complex dynamics of groundwater in general.