Water supply study is well attended

LEWISTON — About 50 people gathered Wednesday evening at the Lewiston Library to learn how water demand might be met if the lower Snake River dams are ever breached as part of an effort to save wild salmon and steelhead.

The study by the U.S. the Bureau of Reclamation and Washington Department of Ecology indicates that breaching the dams would not change the river’s ability to meet current and future water withdrawals for irrigation, or municipal and industrial uses.

But without the dams, the elevation of the river would drop 20 to 120 feet, depending on location, and the water table would drop 3 to 12 feet, making it more difficult and more expensive to access the water.

According to the study, altering or adding to infrastructure to satisfy water withdrawal demand from Lewiston to the Tri-Cities would cost $1.7 billion to $3.5 billion. It is built around a collection of hypothetical fixes. For example, one concept is to build a reservoir on Hatwai Creek along with a pump station and 45 miles of pipelines that would deliver water to the city of Lewiston’s Water Treatment Plant, Clearwater Paper and other users as far away as Wawawai. That fix alone would cost $1.4 billion. A different concept envisions a water diversion and pump station at Lewiston and 43 miles of pipeline at a cost of $660 million.

But those and other fixes in the study are not definitive proposals. Rather, they are concepts designed to provide information to the public and decision makers.

“There would likely be modifications to anything we see here, but what we were trying to do is say, ‘hey, is it possible to continue these water supplies? What are some ways we could do that? And what might it cost to do that,’ ” said Roland Springer, deputy regional director for the Bureau of Reclamation’s Columbia-Pacific Northwest Region at Boise.

Between Little Goose and Lower Monumental dams, the study contemplates a series of wells to deliver water to irrigators and others. Near the Tri-Cities and Ice Harbor Dam, where large farms draw irrigation water from the river, the study proposes building pumping stations and pipelines to replace existing pump stations. The estimated cost there ranges from $950 million to $2.1 billion. However, the Columbia Snake River Irrigators Association has said its members prefer to do the work themselves and estimate it would cost $760 million.

The study stems from a settlement agreement between the U.S. government, the Nez Perce and other Columbia River tribes, the state of Oregon and environmental groups over a lawsuit challenging the federal plan to balance dam operations on the Snake and Columbia rivers with the needs of salmon and steelhead.

The tribes, Oregon and environmental groups are pushing the government to breach the dams. Doing that would disrupt services provided by the dams, including water supply, tug-and-barge transportation, hydropower generation and recreation. The settlement called for studies looking at ways to replace those services. The study is available at bit.ly/40wkODz and is open for public comment through March 1.

Barker may be contacted at ebarker@lmtribune.com or at (208) 848-2273.