Groundwater-Level Monitoring in Oregon

The Oregon Water Resources Department (OWRD) currently measures periodic groundwater levels in about 1100 wells across Oregon. Measurement frequency varies from annual to bimonthly. Eighty-five of the wells are instrumented with automated equipment that records water levels at intervals of 15, 60, or 120 minutes. About 720 wells are associated with groundwater investigations that range in duration from several years to multiple decades. A core set of 380 wells belong to the State Observation Well Network (SOWN) which is designed to monitor changes in groundwater storage in the principal aquifers of the state over extended periods of time. As groundwater investigations mature or are completed, representative project wells are added to the SOWN. In this manner, the network becomes more robust over time. However, wells are periodically lost from the network because of changes in well-owner cooperation, changes in use that preclude the capture of static water levels, or changes in well construction that make measurements difficult or impossible. To avoid many of these problems, OWRD has embarked on a program of drilling dedicated observation wells. Thirteen wells were drilled during the 2014-2015 budget year and an additional dozen are planned for the 2015-2016 budget year.

In 2015, OWRD began participation in the U.S. Geological Survey’s National Ground-Water Monitoring Network. The principal goal of the network is to provide ready access to data from a set of selective wells in existing observation networks that reflect conditions in major aquifers of the nation. In Oregon, this will be accomplished by reviewing existing networks and selecting high-quality, long-term observation wells that best reflect seasonal and long-term water-level trends in the principal aquifers of the state. A review of the goals and progress of this project will be presented.