STORY AND PHOTOS BY KAREN BOSSICK
River cobble slid around John Wright’s feet as he tromped past the Diversion 45 headgate at the north end of Howard’s Preserve.
Ordinarily, the river bed would have been covered by a couple feet of water. But the river had been diverted to the west to enable workers to repair and stabilize its banks where the river makes a turn headed towards the canal.
“They installed wood boards and steel to hold back the streambank and direct water towards the headgate in the 1960s,” said Wright, the diversion watermaster. “But the wood has deteriorated after years of being submerged and exposed over and over again. And trees have grown up in the boards and are pushing them out. So, we’re rebuilding it.”
Workers have used backhoes to rebuild the 6- to 8-foot streambank. They’re installing cottonwood trees and rootballs to help provide stabilization and slow water down during spring runoff. And they’re using woody debris for habitat.
“We’re trying to protect the canal,” said Wright.
Wright, who works on courtesy patrol for Sun Valley Resort during the ski season, visits the canal nearly every day during summer, adjusting the flow and cleaning debris out of the headgate to ensure irrigation water for 120 users downstream.
The new stabilization will protect the canal so the river doesn’t come down in unimaginable fashion during flooding, Wright said.
“The water will be cleaner. It won’t carry rocks and roots into the canal,” he added.
The canal streamflow typically amounts to 300 cubic feet per second, he added. The river can swell to 3,000 cubic feet per second in spring.
The new design employs more natural features than the old design, said Justin Stevenson, Diversion 45 manager. And it should mitigate flooding in the area, according to Bryan Dilworth, Flood Control Dist. No. 9 board member.
“We’ve been dealing with a lot of projects since the 2017 flood and want to support efforts to alleviate flooding while improving the health of the Big Wood,” he added.
The design is the first step in a mile-long strategy to improve the health of the Big Wood River, said Keri York, Big Wood River project manager. The strategy follows a prescription designed by Biota Research and Consulting, Inc., which conducted an assessment of the health of the Big Wood River a few years ago. Additional treatments within a one-mile stretch can be completed as funding becomes available.
The collaborative effort involves landowners, the City of Bellevue, Trout Unlimited, Diversion 45, Wood River Land Trust, the Friends of the Howard Preserve and Flood Control Dist. No. 9. The project is being funded by a flood mitigation grant from the Idaho Department of Water Resources, Flood Control Dist. No. 9 Diversion 45 irrigation districts and Trout Unlimited.
ELHORN FISH LADDER GETS A REMAKE, AS WELL
Trout Unlimited has been working in Lane Ranch this week to replace a fish ladder on Elkhorn Creek so trout can migrate from the Big Wood River to tributary habitat.
Fish have not been able to jump into the upper pond near the Lane Ranch clubhouse because the pond level had been raised with checkboards, noted Bob Law, a Trout Unlimited member. The new fish ladder will have larger pools and space for juvenile fish to pass through, enabling access to spawning and rearing grounds.
The fish ladder has adjustable steps so fish can swim upstream as water levels change throughout the year. There are also notches that will allow juvenile fish to swim through.
Workers had hoped to do the project before the snow flew but had to wait until the ground was frozen enough that equipment could travel across the law without damaging it.
That project is a joint effort by Trout Unlimited, the Lane Ranch Homeowner’s Association and public supporters. Law initiated a multi-year effort to raise funds to replace the non-functional fish ladder.