Accurate location information and water-level data are critical for assessing groundwater resources. Prior to conducting groundwater investigations in a basin, it is necessary to establish long-term, water-level data sets to accurately evaluate climatic, seasonal, and groundwater development impacts on the aquifers.
Today, there are nearly 380 active state observation wells, in addition to about 500 project measurement wells in Oregon. Data are housed in the Groundwater Information System (GWIS).