Moscow Council approves state grant to study Clearwater River diversion as Palouse Basin water alternative

The Moscow City Council on an affirmative vote approved a contract with the Idaho Water Resource Board that will provide $182,500 to study the feasibility of diverting water from the Clearwater River to the Palouse Basin.

The work funded by the contract will assess water availability, develop a conceptual design for intake, pumping, treatment and conveyance, evaluate direct use versus aquifer recharge, perform regulatory and environmental permitting analysis, and support preparation of a water-right application, presenter Tyler Palmer told the council.

“This area is entirely reliant on a declining aquifer system as the sole source of our drinking water,” Palmer said. He described the study as a step toward a specific project: a potential diversion from the Clearwater River and conveyance into the Palouse Basin service area.

Why it matters: the Palouse Basin supplies drinking water to major pumpers including the city of Moscow, the city of Pullman, the University of Idaho and Washington State University. Palmer said the basin’s declining aquifer and long-term demand horizon mean the region needs to assess large regional alternatives rather than rely on conservation alone.

Palmer summarized expected study outputs: an assessment of seasonal and long-term water availability and optimal points of diversion; a conceptual design addressing intake, pumps, treatment, storage and conveyance; identification of anticipated property acquisitions and easements; an analysis of direct use versus aquifer recharge; preliminary cost estimates; a regulatory permitting assessment including tribal consultation; environmental assessments; and stakeholder engagement. He said the contract term is 12 months.

Palmer said the Water Resource Board’s regional water sustainability program aims to help guide state spending on large regional water-supply projects and that Moscow sought funding under that program. He said the city will act as a pass-through for the state funds and will be reimbursed for payments it makes under the contract.

Council members asked about likely environmental impacts and regional coordination. Councilor Gina asked how the diversion could affect salmon runs; Palmer said any impact would be analyzed in the environmental assessments and that the proposed withdrawal would represent “less than 1% of the low flows during dry season.” Councilor Hailey and others asked whether stakeholders were aligned; Palmer said the Palouse Basin Aquifer Committee (PBAC) and a broad group of pumpers, tribal representatives and universities have participated in the project planning and that PBAC strongly supports the work.

The contract was previously reviewed and recommended for approval by the Public Works Finance Committee on Feb. 10, 2024, Palmer said. He described the effort as moving from general research toward a specific project and said a successful study outcome would include submission of a water-right application.

Council action: A motion to approve the regional water sustainability funding contract with the Idaho Water Resource Board passed by recorded voice vote (Sandra — Aye; Julia — Aye; Hailey — Aye; Bryce — Aye; Gina — Aye; Drew — Aye). The council vote and Palmer’s presentation indicate the city will next select a consultant, negotiate a scope of work and return to the council to approve the contract with the selected consultant.

What comes next: staff said it has completed two interviews with consultant finalists, expects to negotiate a scope, and will return to the council for contract approval. The project schedule in the contract anticipates roughly a 12-month study with monthly project-management meetings and quarterly written reports to the city.