Synopsis:  This project seeks to use high resolution floodplain information to model the influence of surface/groundwater interactions on stream temperature in the Upper Umatilla River.  

Introduction:  
We propose to continue floodplain assessment methods to evaluate the importance of hyporheic exchange, geomorphic diversity and temperature patterns to salmon productivity in the Umatilla River.  This approach has used several remotely sensed and field data sets to identify drivers of hyporheic flows and the critical late summer salmon habitats.  In 2008 we propose to use much of the data generated through previous assessments to model existing and hyporheic influence on stream temperature in the Umatilla River.  Prior research has shown that geomorphically diverse floodplains maintain thermal and physical habitats that salmon rely on (O’Daniel et al. 2003).  Historically, the Umatilla River included critically important habitats that are now rare.  A uniform assessment of hyporheic flows can greatly inform the restoration options pursued by individual agencies. Using modeled, field and remotely sensed information from this river, we will quantify the effects of shallow and deep groundwater on instream habitat in the Upper Umatilla River.  This effort represents the a variety of past and ongoing research efforts that began in Umatilla Basin and would build upon existing facilities, stream databases, and remote-sensing imagery compiled by the Confederated Tribes of the Umatilla Indian Reservation. Additionally, this project continues work begun in a 2001 Innovative Project (#200101100), (~$340,000) and is also supported by a NASA grant (#NAG 13-02030), (~$1,900,000). These past and ongoing projects continue to contribute to peer reviewed publications and increased effectiveness in understanding and addressing floodplain habitats.  Expected benefits of this project include:  1) development of model outputs to identify the importance of hyporheic flow to salmonid habitats and 2) an estimate of the magnitude of temperature dampening associated with shallow and deep groundwater throughout the Mission floodplain of the Umatilla River.

Goal:  In order to better guide stream restoration efforts, we propose to model the influence of ground/surface water interaction on stream temperature and the effects on native fish. Our goal is to deliver critical information and tools into the hands of the project biologist to foster more effective restoration projects throughout the Columbia River Basin.

Justification: Stream restoration projects often seek to change channel geometry, either directly, by creating a new stream channel, or indirectly by adding roughness elements in other instream engineering structures.  These channel altering activities influence the hyporheic zone by changing channel geometry and slope, also the rate and pattern of surface/groundwater exchange.  We propose a modeling project that uses high resolution data sets (primarily created in previous efforts) to demonstrate 1) the correlation between increased surface/groundwater exchange and diverse floodplain features, 2) the influence of shallow and deep groundwater on surface water temperature patterns and 3) to develop an example in the Mission floodplain of the Upper Umatilla River, where approximately ½ of the floodplain is highly functional and ½ is diked.