The Washington Department of Ecology will spend $250,000 to study whether Lake Pend Oreille could be tapped to provide water for better flows in the Spokane River.
The study revolves around a simple hypothesis: Water would be collected during the spring runoff and pumped into the Spokane Valley/Rathdrum Prairie Aquifer. The water would move gradually through the aquifer, reaching the river after it crosses the Idaho-Washington border.
“Lake Pend Oreille is a huge system,” said John Covert, a hydrogeologist with the Ecology Department, noting that about 18 million acre-feet of water enters and leaves Idaho’s largest lake each year. “We’re looking at whether we could siphon a little bit of that off … and put it to work in the Spokane River.”
Summer flows in the river have declined dramatically over the past century. By August, only 100 cubic feet of water per second trickle over the rocks in some places, creating warm, stagnant pools that are bad for fish.
The lower flows are the result of population growth and a higher summer pool in Lake Coeur d’Alene, Covert said. Lake levels are manipulated by the Post Falls Dam, which keeps water in the lake for summer boating and recreation, allowing less to flow down the river.
The region’s rapid growth is also a significant contributor to lower river flows, he said. Most of the region gets its drinking water from the aquifer, which is connected to the river. As water is pumped from wells on the Rathdrum Prairie to meet the needs of new subdivisions, less groundwater is flowing west into the Spokane River, Covert said.
“One of our notions is that this would benefit everybody if we could make it work,” said Covert, who believes that a recharge could avert future water conflicts between Washington and Idaho.
Rachael Paschal Osborn, a Spokane water attorney, wonders what Idaho residents will think of the idea.
“One state investigating a water diversion in another state is kind of unusual,” Osborn said. “I have heard people in Idaho say if they could figure out how to keep all of the water in Idaho … that would make them very happy,” she said. That’s a typical sentiment for upstream states, Osborn added.
Washington users have coveted Lake Pend Oreille’s vast water resources in the past, she said. Before construction started on the Columbia River’s Grand Coulee Dam in 1933, there was a congressional investigation into the idea of pumping water from Lake Pend Oreille to irrigate Eastern Washington farmland, Osborn said.
Results from the Ecology study will be released in mid-2010. The study, performed using computer modeling, also will examine whether water from Lake Coeur d’Alene or spring flows from the Spokane River could be used to recharge the aquifer and boost the river’s summer flows.
The Idaho Department of Water Resources is aware of the Ecology study and supports gathering that type of data, said Bob Haynes, regional manager in Coeur d’Alene.
“We need to understand what the potential for augmenting flows in the Spokane River is,” he said.
However, Haynes said, it would be premature for the department to take a stance on whether it would support diversions from Lake Pend Oreille.
The two states are trying to work cooperatively on Spokane River issues, he added. The river flows out of Lake Coeur d’Alene, about 15 miles west of the state line. The two-state watershed covers about 2,400 square miles.
Idaho residents enjoy seeing water flowing over the falls in downtown Spokane, just like Washington residents do, Haynes said. They also fish, raft and kayak on Washington stretches of the river.
“If we don’t craft solutions that come from cooperation, we will have solutions delivered by the courts,” Haynes said. Lawsuits are expensive, he added, and don’t necessarily result in the best solutions for residents.
Ecology’s Covert said the study will investigate the technical aspects of aquifer recharge, such as cost, and how water levels in Lake Pend Oreille would be affected. The study won’t address the proposal’s political feasibility.
“Will they be able to create a pulse of water that they can control?” asked Osborn, the water attorney. That’s a big question, she said. “I’ll be very curious to see what the study says.”