Walla Walla River Basin groundwater-flow system, Oregon-Washington
The Issue: Decades of declining groundwater levels in the Walla Walla River Basin (WWRB), which spans Oregon and Washington, are affecting instream flows for threatened and culturally important fish populations and water availability for competing interests across state lines. The public and state resource management agencies have begun implementing efforts to stabilize groundwater levels and restore instream flows but need an improved understanding of the full WWRB groundwater-flow system to effectively manage and protect this valuable resource.
How USGS (Oregon and Washington Science Centers) will help: In close cooperation with water-resource agencies and stakeholders from Oregon and Washington, the USGS will collect new hydrologic data and aggregate data from past studies to better understand (a) the extent and connectivity of groundwater in the basin, (b) the impacts of pumping on groundwater levels, (c) the locations of gaining and losing stream reaches and the volume of water being exchanged in those reaches, and (d) the quantity of groundwater recharge, discharge, and water use in the basin. This understanding is needed for informed management of water resou
Problem: Groundwater levels in the WWRB have been declining since the 1940s. Surface water is over appropriated, and groundwater declines reduce summer streamflow required for fish populations, including several listed as threatened under the Endangered Species Act. The WWRB spans the state boundary of Oregon and Washington, adding to the challenge of managing the basin’s water resources.
Past studies provide a general understanding of the groundwater-flow system in the WWRB, but changes in groundwater use, evolving water rights law, and the scope and scale of earlier studies limit comprehensive understanding of the full system. Holistic water resource management in the WWRB requires an improved and quantitative understanding of the relationship between groundwater within hydrogeologic units of the Columbia River Basalt Group and the overlying sedimentary units, and between groundwater and surface water.
Objectives: The study objective is to develop a quantitative and conceptual understanding of the WWRB groundwater-flow system. The scope consists of estimating rates and distribution of groundwater recharge and discharge throughout the basin, quantifying the interaction of groundwater and surface water, identifying major hydrogeologic units, characterizing hydrogeologic controls on groundwater flow, and estimating potentiometric surfaces and groundwater-flow paths. A future phase of this study (Phase II) will focus on developing a simulation tool to assess flow-system conceptualization and simulate effects of potential future water-use scenarios on water resources in the basin.
The Issue: Decades of declining groundwater levels in the Walla Walla River Basin (WWRB), which spans Oregon and Washington, are affecting instream flows for threatened and culturally important fish populations and water availability for competing interests across state lines. The public and state resource management agencies have begun implementing efforts to stabilize groundwater levels and restore instream flows but need an improved understanding of the full WWRB groundwater-flow system to effectively manage and protect this valuable resource.
How USGS (Oregon and Washington Science Centers) will help: In close cooperation with water-resource agencies and stakeholders from Oregon and Washington, the USGS will collect new hydrologic data and aggregate data from past studies to better understand (a) the extent and connectivity of groundwater in the basin, (b) the impacts of pumping on groundwater levels, (c) the locations of gaining and losing stream reaches and the volume of water being exchanged in those reaches, and (d) the quantity of groundwater recharge, discharge, and water use in the basin. This understanding is needed for informed management of water resou
Problem: Groundwater levels in the WWRB have been declining since the 1940s. Surface water is over appropriated, and groundwater declines reduce summer streamflow required for fish populations, including several listed as threatened under the Endangered Species Act. The WWRB spans the state boundary of Oregon and Washington, adding to the challenge of managing the basin’s water resources.
Past studies provide a general understanding of the groundwater-flow system in the WWRB, but changes in groundwater use, evolving water rights law, and the scope and scale of earlier studies limit comprehensive understanding of the full system. Holistic water resource management in the WWRB requires an improved and quantitative understanding of the relationship between groundwater within hydrogeologic units of the Columbia River Basalt Group and the overlying sedimentary units, and between groundwater and surface water.
Objectives: The study objective is to develop a quantitative and conceptual understanding of the WWRB groundwater-flow system. The scope consists of estimating rates and distribution of groundwater recharge and discharge throughout the basin, quantifying the interaction of groundwater and surface water, identifying major hydrogeologic units, characterizing hydrogeologic controls on groundwater flow, and estimating potentiometric surfaces and groundwater-flow paths. A future phase of this study (Phase II) will focus on developing a simulation tool to assess flow-system conceptualization and simulate effects of potential future water-use scenarios on water resources in the basin.