Spokane and Stevens counties will use $2 million in state grants to accommodate rural housing growth while keeping water in streams for fish and other wildlife.

Spokane County was awarded $1 million to purchase additional water rights in the Little Spokane River watershed, where groundwater has been scarce for decades. By acquiring water rights and banking them for future development, the county ensures that new rural homes with permit-exempt wells aren’t reducing stream flows or depleting their neighbors’ water source.

Stevens County received $1 million for a water trade that will allow housing development to continue in the Colville River watershed.

The grants were part of $20 million awarded to 15 Washington communities this week by the Department of Ecology. Last year, the Legislature created the grant program in response to the state Supreme Court’s 2016 decision in Hirst v. Whatcom County.

The Hirst decision requires anyone seeking a construction permit to prove there is enough groundwater to supply a proposed development without depleting river flows or infringing on a neighbor’s water rights.

After the Hirst decision, Spokane County halted permits for new construction in the Little Spokane River watershed for more than a year. The county resumed issuing construction permits after it purchased two water rights to offset the rural residential growth.

The grant will allow Spokane County to purchase four additional water rights to make up for future water use from domestic wells, said Mike Hermanson, the county’s water resources manager. New exempt domestic wells in the Little Spokane River watershed will be allowed an annual average water use of 3,000 gallons daily. Despite the acquisition of water rights, some localized groundwater availability issues could still occur, Hermanson said.

About 2,180 new rural residences are projected to be built over the next 20 years in the watershed, which covers parts of Spokane, Stevens and Pend Oreille counties. Those residences are expected to consume about 1,650 acre feet of water annually, according to a draft update for demand analysis in the watershed plan.

The state requires local governments to plan for how they’ll offset new demands for rural domestic use, said Jaime Short, water resources section manager for the Department of Ecology’s Eastern regional office in Spokane.

Spokane County could look at a variety of offset options in the future, including storing groundwater and releasing it at strategic times, Hermanson said.

In Stevens County, the $1 million grant will support a water trade benefiting the Colville River watershed, where flows don’t meet state standards for protecting fish and habitat for other wildlife, Short said.

The exchange involves water from Sullivan Lake in Pend Oreille County, which has been designated by the state to support projects in up to six counties. That water will be traded on paper for water secured at Waitts Lake by Avista Corp. to offset a well drilled at the company’s biomass generating plant near Kettle Falls.

Stevens County officials preferred the exchange over the purchase of water rights in the watershed because they didn’t want to reduce acreage for irrigated cropland.

The exchange will provide enough water to support rural development in the Colville River watershed for the next 20 years, Short said.

This story was updated to correct the number of new rural residences projected in the Little Spokane River watershed, and adds an additional comment from Mike Hermanson.