Planning Without a Baseline: Water Rights Adjudication and Sustainability in the Spokane Valley Rathdrum Prairie Aquifer

Faculty Mentor

E.D. Dascher

Presentation Type

Poster

Start Date

4-14-2026 11:30 AM

End Date

4-14-2026 1:30 PM

Location

PUB NCR

Primary Discipline of Presentation

Urban and Regional Planning

Abstract

This project examines the management of the Spokane Valley–Rathdrum Prairie (SVRP) Aquifer, an EPA designated sole-source aquifer and the primary source of drinking water for communities in Spokane County, WA and Kootenai County, ID. The aquifer is also an important contributor of flow to the Spokane River. Groundwater from the aquifer helps sustain river flows during the dry season and prolonged droughts, supporting aquatic habitat and maintaining ecological conditions for fish and other wildlife. However, increasing groundwater withdrawals, particularly during the summer months, reduces the aquifer’s ability to support river flows and maintain these ecological functions. Although groundwater withdrawals are regulated through existing state water rights systems, management of the aquifer is complicated by unresolved water rights claims and the aquifer’s transboundary location. Washington follows a “first in time, first in right” doctrine for allocating water rights, but the state has not yet completed a full adjudication of claims in the Spokane River Basin. Without adjudication, it remains unclear which claims are valid, how much water each right holder may withdraw, and the order in which withdrawals would be curtailed during water shortages. This uncertainty limits the ability of the Washington State Department of Ecology to fully administer water rights and enforce restrictions when water supplies are limited. This project argues that adjudicating water rights in the basin is a necessary step toward more effective groundwater management and protection of instream flows. However, adjudication alone will not resolve all management challenges. Long-term sustainability of the aquifer will likely require additional measures, including improved groundwater monitoring, water conservation efforts, and greater interstate coordination between Washington and Idaho. Based on previous adjudications in the regions, the process could take over a decade and require substantial state investment but ultimately would provide the legal clarity needed to better manage groundwater withdrawals and protect the long-term health of the aquifer and the Spokane River System.

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Apr 14th, 11:30 AM Apr 14th, 1:30 PM

Planning Without a Baseline: Water Rights Adjudication and Sustainability in the Spokane Valley Rathdrum Prairie Aquifer

PUB NCR

This project examines the management of the Spokane Valley–Rathdrum Prairie (SVRP) Aquifer, an EPA designated sole-source aquifer and the primary source of drinking water for communities in Spokane County, WA and Kootenai County, ID. The aquifer is also an important contributor of flow to the Spokane River. Groundwater from the aquifer helps sustain river flows during the dry season and prolonged droughts, supporting aquatic habitat and maintaining ecological conditions for fish and other wildlife. However, increasing groundwater withdrawals, particularly during the summer months, reduces the aquifer’s ability to support river flows and maintain these ecological functions. Although groundwater withdrawals are regulated through existing state water rights systems, management of the aquifer is complicated by unresolved water rights claims and the aquifer’s transboundary location. Washington follows a “first in time, first in right” doctrine for allocating water rights, but the state has not yet completed a full adjudication of claims in the Spokane River Basin. Without adjudication, it remains unclear which claims are valid, how much water each right holder may withdraw, and the order in which withdrawals would be curtailed during water shortages. This uncertainty limits the ability of the Washington State Department of Ecology to fully administer water rights and enforce restrictions when water supplies are limited. This project argues that adjudicating water rights in the basin is a necessary step toward more effective groundwater management and protection of instream flows. However, adjudication alone will not resolve all management challenges. Long-term sustainability of the aquifer will likely require additional measures, including improved groundwater monitoring, water conservation efforts, and greater interstate coordination between Washington and Idaho. Based on previous adjudications in the regions, the process could take over a decade and require substantial state investment but ultimately would provide the legal clarity needed to better manage groundwater withdrawals and protect the long-term health of the aquifer and the Spokane River System.