This recent KTVB story highlights the work of GeoEngineers’ Boise office, where we are currently contracted with The Nature Conservancy (TNC) to develop designs, secure environmental permits and oversee the construction of the enhancement of Silver Creek near Sun Valley, Idaho. This crystal clear, spring-fed creek was made famous by Ernest Hemmingway who fished its waters for the giant Rainbow and Brown Trout that inhabit this world-renown nature preserve.

One portion of the creek, known as Kilpatrick Pond, is controlled by a small 100-year-old irrigation dam on the downstream neighbor’s ranch. In addition to preventing upstream fish passage, this dam has converted this historically deep, narrow, meadow stream into a slow, warm, sediment-laden pond. During the hot summer months the pond is responsible for elevating stream temperatures as much as 10 degrees Fahrenheit; causing fish kills downstream. The GeoEngineers design team, which includes Jeff Fealko, Jason Poulsen, Ryan Carnie, Paul Wasser, Jason Scott and Mike Homza, is developing designs that involve constructing streamside wetlands that will narrow the stream, increase water velocities, maintain sediment conveyance, reduce residence time, reduce temperatures and increase and enhance in-stream and wetland habitat.

University of Idaho graduate students (one of whom is our own Ryan Carnie) have assisted in this design by developing a physical model in the university’s hydraulic flume. In addition, graduate students from Washington State University (one of whom is our old coworker Evan Miller) are double-checking the flume results with a 2-dimensional computer model. The information provided by the students will help us fine-tune our design. We are also collaborating with the downstream rancher and his engineer on similar stream enhancement, fish passage and dam designs. GeoEngineers’ Paul Wasser has initiated discussions between TNC and Idaho Transportation Department (ITD) so ITD can help fund this project in return for wetlands banking credits.

The project may potentially involve diverting the whole creek out of the existing channel for several thousand feet during construction and require the temporary removal of thousands trout for which the creek is famous. To take advantage of this opportunity, our team is working with the Idaho Department of Fish and Game (IDFG) to develop a fish tagging/monitoring program. Construction is currently scheduled to occur in the fall of 2012.

This project exemplifies how GeoEngineers’ multidisciplinary team of river engineers, geotechnical engineers, biologists and environmental specialists collaborates amongst ourselves and the broader community to enhance and improve our world’s natural and human resources.