Informing surface water flow  and groundwater storage strategies with science.

USGS Groundwater Study

Learn more about the study!

To improve understanding of the Walla Walla Watershed’s hydrologic system and fill significant data gaps in groundwater use, the Oregon Water Resources Department, Washington Department of Ecology, and the Confederated Tribes of the Umatilla Indian Reservation are collaborating with the U.S. Geological Survey to conduct a groundwater study of the watershed. By developing and refining how groundwater moves, water managers will be able to make better long-term decisions that affect water use.  The project is building water budget, and flow model to help guide management and planning across state lines. We expect the first phase to be completed by 2026.

Walla Walla Bi-State Flow Enhancement Study

The overarching purpose of the Flow Study is to improve streamflow in the reach of the Walla Walla River mainstem extending from the controlled diversion into the Little Walla Walla River near Cemetery Bridge in Milton-Freewater, Oregon, to the confluence with the Columbia River near Wallula, Washington. The primary objective of the Study is to sustain streamflow at levels that support naturally sustaining harvestable populations of native fish species, while maintaining the long-term viability of agricultural, municipal, commercial, and residential uses of water.

The Flow Study aims to sustain these streamflow targets throughout the entire reach of the Walla Walla River from Cemetery Bridge to the mouth. Another objective of the Flow Study is to return to irrigators the portion of the historically diverted streamflow that they voluntarily and temporarily agreed to bypass for fish in 2000. Water conserved through implementation of this study will remain instream as required by individual conservation funding agreements and Oregon conserved water statutes.

US Bureau of Reclamation Basin Study

The United States Department of the Interior, Bureau of Reclamation (Reclamation) and the Department of Ecology’s Office of the Columbia River, Confederated Tribes of the Umatilla Indian Reservation’s Department of Natural Resources, and Oregon Water Resources Department agree to work collaboratively to perform the Walla Walla Basin Study (Study) as part of the WaterSMART Basin Study Program.  This Memorandum of Agreement (Agreement) establishes the terms that will guide the performance of the Study.

The Walla Walla Basin in both Washington and Oregon includes the Walla Walla River basin watershed extending across Washington and Oregon State borders that encompasses an area of approximately 1,760 square miles. In the Walla Walla River basin water resources are over-appropriated, the flood plain is channelized and fragmented, and there are numerous fish passage issues, extirpation of certain native salmonids, and a steady decline of other native aquatic species. Therefore, the general objectives of the Study are to:

  • Review the work already performed and assess whether all water supply demand needs within the basin have been fully considered and how water from the Columbia River might be used to replace or reduce existing diversions

  • Analyze water supply challenges and opportunities within the basin

  • Review, modify, and/or develop alternatives to address water supply imbalances and improve water supply delivery and biological reliability within the basin

  • Review and/or develop proposed conceptualized facility plans, cost estimates, and benefits of each alternative

  • Discuss regulatory and institutional framework or impediments that need to be addressed to successfully implement the Walla Walla 2050 Plan strategy