For seven years, raising the Boise River’s Arrowrock Dam has been proposed as a way to provide flood control and additional water supply to the Treasure Valley. As of this week, the dam raise is off table.

ICL has long opposed raising Arrowrock, advocating that instead there are less destructive ways to address the majority of flood control needs-including   prevent additional floodplain development, reconnect Boise River side channels, retrofit specific bridges-and that future water demand can be addressed by changing how we manage the water we already have. In addition to being viable, these ideas are far cheaper than raising the 100-year old dam, and they have none of the associated ecological impacts.

No Dam Raise

The Idaho Water Resource Board is tasked with managing water supply; the Army Corps of Engineers works to prevent floods. In this instance, they were 50/50 partners in the dam proposal. This week for the first time a public cost estimate for the dam raise was provided: $1.3 billion.

On Wednesday, the Army Corps of Engineers told a stunned Idaho Water Resource Board that an Arrowrock raise did not pencil out and, thus, the Corps could no longer pursue the project. The Corps requires a cost-benefit ratio of at least 1 to proceed; the ratio for Arrowrock was .7. The Corps’ announcement essentially makes the dam raise a nonstarter.

Where Will Our Water Come From?

The Treasure Valley doesn’t have to reinvent the wheel to address its future water needs, it just has to modernize the way water is managed. Looking to other arid western cities is instructive. Incentives for reduced water use-such as paying people to xeriscape, tiered pricing for domestic irrigation water, and building codes-helped Las Vegas’ population grow while also reducing water use.

But the Treasure Valley’s biggest potential gains lie in how water formerly needed for farms is currently distributed to land that is increasingly commercial and residential. More than 85% of water diverted in the Treasure Valley is distributed as if it was for irrigated agriculture. This is despite increasing amounts of farmland turning into neighborhoods and commercial properties-read: roofs, driveways and parking lots that do not need or absorb water. Much of this land receives the same amount of water now that it did when it was irrigated for agriculture.

To the Future!

The answers are out there, and in order to thrive in our future we have to be willing to make some changes in how we use, market and move water. Change can be hard, and as a community we have some big discussions ahead. And now that the dam raise is off the table, it’s time to elevate those conversations and plan a reliable water future.