GSI’s team supported the Columbia Basin Ground Water Management Area (CBGWMA) efforts to conduct a multi-phased, basin-wide groundwater management project. Using our extensive knowledge of regional and local hydrogeology, GSI collaborated with local stakeholders to address the basin’s groundwater supply problems by conducting aquifer assessments, subsurface mapping, and groundwater modeling of the Columbia River Basalt Group aquifer system.

Background

The CBGWMA of Adams, Franklin, Grant, and Lincoln Counties which, covers more than 8,400 square miles and has a generally semi-arid climate, is home to more than 200,000 citizens, and hosts some of the most productive farmland in the United States. Unfortunately, the groundwater system that supplies this area is at risk. In some areas nitrate concentrations pose a risk to potable supplies. In other areas groundwater mining of the primary basalt aquifer system jeopardizes water user’s long term access to usable water. The goal of the CBGWMA and the GSI team was to help stakeholders to develop sustainable groundwater management solutions ranging from changing irrigation practices to developing a better understanding of groundwater sources and sustainable pumping conditions.

GSI’s Solution

Working closely with CBGWMA staff we provided input on a variety of topics such as the groundwater conditions in the Odessa Subarea, meeting with Ecology staff to discuss well construction and water level data, and meeting with stakeholders and the public to discuss basic geology and hydrogeology in the CBGWMA. Our understanding of the limited availability of recharge to CBGWMA basalt aquifers is being used by CBGWMA and its local stakeholders to inform well construction, groundwater supply, future water supply potential, and develop sustainable management strategies. Work conducted to date includes:

  • Conducting a subsurface mapping project to understand the geologic and hydrogeologic characteristics of the region.
  • Assessing and evaluating recharge sources for the basalt aquifers, the age of groundwater within them, and the degree of hydrologic continuity between these basalt aquifers and surface water.
  • Developing a regional groundwater model that encompasses the unique physical geology of the Columbia River basalt aquifer system.
  • Evaluating the long-term viability of municipal groundwater supplies.
  • Identifying areas where modern recharge is supporting irrigation well pumping.
  • Showing stakeholders areas where groundwater mining is a real risk versus those where groundwater recharge may be able to support continued groundwater pumping, such as near major canals and natural water bodies
  • Developing local-scale modeling-based water-budget assessments for each municipality inside GWMA.
  • Presenting to public officials and citizens about study results.
  • The results of the CBGWMA work helped inform the U.S. Geological Survey revise the Columbia Basin RASA model and the U.S. Bureau of Reclamation in its work on the Odessa Special Study.

Starting in 2014 GSI and its teaming partners have been helping CBGWMA launch an aquifer storage and recovery (ASR) feasibility study for the Cities of Othello and Moses Lake. The feasibility study seeks to determine if ASR was a viable water supply option for these two cities and if ASR will provide additional recharge to the aquifer system. If feasible, this work will provide a framework for other cities and irrigators in the basin to use ASR for water supply and basin recharge.


This video was developed and produced by Columbia Basin Ground Water Management Area