Year Established: 2012 Start Date: 2012-03-01 End Date: 2014-02-28
Total Federal Funds: $28,000 Total Non-Federal Funds: $56,004
Principal Investigators: Geoffrey Poole
Abstract: Elevated stream water temperature is a persistent problem in the northwestern United States, where migratory and resident salmonid fishes (Oncorhynchus spp., Salvelinus spp., and Salmo spp.) are an important natural resource dependent upon cool water. The Environmental Protection Agency's regulatory structure for managing water temperature in this region is organized around the needs of cold-water organisms such as salmon and trout. In western rivers, enhancement of stream side shade is not an adequate solution for mitigating high stream temperatures and other approaches are required. Recent research suggests that channel restoration methods that target re-establishment of the surface and subsurface water exchange (e.g. hyporheic exchange) is a possible method to effectively reduce summertime diel temperature swings in rivers with excessive temperature problems. However, there are no published assessments of hyporheic and water temperature response to channel restoration efforts at the scale of a whole stream reach. In essence, scientists and managers do not know if conventional restoration techniques address the imperative for restoration of hyporheic hydrology. In summer 2011, the Confederated Tribes of the Umatilla Indian Reservation (CTUIR) completed a large channel restoration project along a one-mile (1.6 km) reach of Meacham Creek, an important salmon-spawning tributary to the Umatilla River, Oregon. This restoration effort included channel realignment (re-meandering) and addition of large woody debris to the site with the specific objective of increasing hyporheic exchange. Our research combines a variety of field and numeric modeling techniques to create a complete picture of the residence time distribution for hyporheic water on the site for both pre- and post- restoration conditions and will document the effects of channel re-alignment on hyporheic exchange, hyporheic flow path lengths, residence time, and ultimately, channel temperature. We expect that this research will provide local and regional fishery managers with the information necessary to begin to incorporate hyporheic restoration strategies into their management plans.