Wagner Creek Diversion Structure To Be Replaced With Fish-Friendly Design
Geos Institute recently completed landowner and water user agreements with 19 parties that will allow the replacement of a diversion structure on Wagner Creek near Talent, Oregon, with a structure that will allow fish of all size to pass quickly and safely. The existing structure is old, leaky, and nearly impossible for fish to migrate past during spring, summer, and fall months. Even during winter, water flows must be just right to permit adult fish to pass. Geos Institute is now working with Cascade Stream Services to design a structure that will allow the water users to continue diverting their water right while also allowing even small fish to swim past the site under all but the most extreme flow conditions.
In 2013, Geos Institute entered into a replacement agreement with Cascade Stream Services, the owners of the land where the Beeson-Robison diversion structure crosses Wagner Creek, and 17 other parties. The current structure, which supplied 13 irrigators, presented several major impediments for steelhead and coho returning to their spawning grounds in Bear Creek. Between April and October, the stream was completely blocked by the diversion structure, allowing no fish to pass upstream. Upstream passage was sometimes possible during the winter months, but required a three-foot-high vertical jump to clear the concrete sill. Although the diversion was screened, the existing bypass pipe dropped fish from a height of four feet into a shallow pool, an unnecessary stress that made downstream travelers more vulnerable to predation and disease.
In partnership with Cascade Stream Solutions, Freeways for Fish recommends replacing the outdated diversion dam with an improved irrigation water collection box which can provide more reliable flow than the old structure. After removing the dam, Freeways for Fish proposes a 160-foot, 5% gradient re-profiled stream channel with step-pool sequences for fish passage as well as downwells to transition screened fish safely back to Wagner Creek. These changes will result in year-round fish passage while also maintaining the diversion rate, a benefit for wildlife as well as irrigators.