Officials await PBAC report on pump test

Information from a pre-Thanksgiving shutdown of Palouse groundwater pumps could begin rolling in as soon as next week. Colfax, Moscow, Palouse, Pullman, the University of Idaho and Washington State University all shut down water pumps to begin a year-long study by the Palouse Basin Aquifer Committee.

The test is intended to get a clearer picture of the connectedness of groundwater supplies on the Palouse. With that information, officials hope to better target conservation efforts.

The shutdown drew reservoirs for each entity to approximately half-capacity.

Steve Robischon, director of PBAC, told the Gazette Monday a team of UI researchers will begin to glean information from the pumps as soon as this week.

Robischon said the first round of information may yield preliminary data of how each agency’s pumps affect those of the other agencies.

Robischon said data from monitoring wells between each city should show whether water levels decrease when neighboring water systems switch on pumps.

All the entities shut down their pumps around 10 p.m. Nov. 23, and they switched them on in increments of approximately one hour Nov. 25.

Data from the monitor wells immediately following the resumption of pumping could show if the cities share common groundwater aquifers.

He said this is the first real study of groundwater in Colfax. Research should show if Pullman pumping affects Colfax wells.

Earlier studies have shown groundwater levels around Palouse lower when Moscow and Pullman switch on their pumps.

That may be a coincidence, Robischon cautioned. He said barometric pressure in the atmosphere could also be responsible for the decreased water level.

As air pressure lightens, he explained, the water level in the aquifer rises. Higher pressure pushes the water level down.

The impacts from the atmospheric changes has led to inconclusive results from previous researchers, he said.