A study ran by the Palouse Basin Aquifer Committee (PBAC) and the Idaho Water Resource Board, which began in 2025, has been created to determine the feasibility of diverting water from the river up to the Palouse Groundwater Basin. Potential intake locations were discussed on Thursday, Oct. 25 when PBAC held its 23rd Palouse Basin Water Summit.
Timothy E. Link is the Professor of Hydrology at the University of Idaho, as part of the College of Natural Resources. He is also the director of the Water Resources Graduate Program. He served on PBAC from 2021 to 2023, when the organization was investigating diverting water from the Snake River, instead of the Clearwater. This was abandoned, since the municipalities were unlikely to get water rights in the state of Washington.
During an interview with the Argonaut, Link described his apprehension about diverting from the Snake River.
“My concern for a Snake River diversion was that it’s below the Clearwater Paper outfall . . . in terms of discharge coming out of the mill . . . [it] historically included some permitted but concerning toxics and carcinogens,” Link said.
The water would have been treated before being used in the municipal water system, as will the water from the Clearwater River. However, Link said it could spark concern and pushback from the public. The new Clearwater diversion chosen this October is above the mill, while the Snake River sites were below it.
The project, as discussed in the study, would include the pumping of water from the Clearwater River to be treated in Moscow and Pullman. This would result in a pipeline of over 40 miles, along either US 95 or US 195.
“Realistically, we’re probably around ten to 20 years out before [the Clearwater River project] will happen,” says Link. “Conservation has an immediate impact . . . [and] is a really important tool until projects are developed.”
The Palouse Groundwater Basin is “a big bowl, with Moscow Mountain to the north [and] Paradise Ridge to the south,” as described by Link. Said ‘bowl’ is a “layer cake of basalt that is very fractured and heterogenous, with interstratified beds of sediments between” and a bottom of granitic bedrock.
The basin is made up of two aquifers: the shallower Wanapum and deeper Grand Ronde. Municipal wells can be used to detect water levels of the basin, of which the City of Moscow has six.
In 2025, Moscow and Pullman pumped over two billion gallons from the basin, as mentioned by Emily Pearce in her Moscow-Pullman Daily News article. “Groundwater levels are declining in Moscow,” said Link. Conservation efforts have reduced the rate at which the aquifer is depleted, with a “current rate of around 0.75 feet” lost each year currently. “At some point, the cost of water would get more expensive,” Link continued, “and at some point, the bowl will be empty.” Link says this is why conservation efforts, and projects like the Clearwater River Diversion Study, are so important.
Addressing water resource issues can be a long process. Work, which includes the Clearwater River Diversion study, has been decades in the making due to the longevity of the process to identify and develop new sources for diversion.
Link suggests converting to native, drought resistant plants for house-owners and their lawns. Low-flow shower heads and toilets can also be implemented. For more information, PBAC has an outreach page dedicated to meaningful ways everyday people can work to conserve water resources. Link says, “[we] can still have the quality life that water provides while still reducing the amount of use.”
Maddie Wright can be reached at [email protected]