We propose to develop floodplain assessment methods to evaluate the importance of hyporheic exchange, geomorphic diversity and temperature patterns to salmon productivity in the Umatilla River. This approach will use several remotely sensed and field data sets to identify drivers of hyporheic flows and the critical late summer salmon habitats. Prior research has shown that geomorphically diverse floodplains maintain thermal and physical habitats that salmon rely on. Historically, the Umatilla River included critically important habitats that are now rare. A uniform assessment of hyporheic flows creates a basin-wide dataset to better understand and manage these habitats. Using modeled, field and remotely sensed information from this river, we will quantify relationships between physical and biological habitat parameters that impact salmon productivity. This effort represents the culmination of 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 an integrated collaborative effort between Tribal Government, federal researchers, and small business. Additionally, this project continues work begun in a 2001 Innovative Project (~$340,000) and is also supported by a NASA #NAG 13-02030, (~$1,900,000). These past and ongoing projects continue to contribute to peer reviewed publications (3 published and 2 in review) and increased effectiveness in understanding and addressing floodplain habitats. Thus the CTUIR is able to leverage a significant investment (>$2,200,000) of data and scientific knowledge to provide a highly efficient use of requested funds. Expected benefits of this project include: 1) development of rapid assessment techniques to document nodes of diverse floodplain habitats and build a basis for hyporheic habitat management and 2) provision of new methods to measure the effect of shallow hyporheic exchange over entire tributary rivers. This research will provide a means to link salmon habitats to dynamic physical environments that create and maintain them.

Technical background
Stream temperature is an overriding control on biological function in aquatic systems (Ward 1995, Stanford 1997). Further, elevated stream temperatures are the most pervasive limitation.  Work from our research group (Arrigoni et al. submitted) has shown that short hyporheic flow paths (2-40m in length) can reduce the maximum and minimum diel stream temperature along alluvial rivers. In diverse channels this exchange of stream water through gravel bars buffers water temperatures and is associated with a variety of diverse floodplain features.

Water temperature is a dominant habitat characteristic that controls physiological processes, distribution and abundance of aquatic organisms (Allan and Johnson 1997, Coutant 1999, Ward, 1982). Water temperatures, like other stream phenomena, are conditioned be the spatial dimensions of river systems, specifically, the channel, alluvial aquifer and the riparian zone (Ward 1989, Stanford and Ward 1993, Townsend 1989, Poole 2004). Among these interdependent components, the hyporheic zone often exerts strong control on alluvial rivers with active floodplains (Ward 1989). Examples from throughout the Columbia River Basin (CRB) show that anthropogenic changes to alluvial floodplains have limited the historic expressions of physical and ecological processes necessary to maintain adequate diversity of stream habitats ([Sedell 1982; McIntosh, 2000). However, a surprising number of rivers retain characteristics of functional alluvial processes. Where effective alluvial processes are found, complex interactions result in increased diversity in stream habitats and organisms. For example, active hyporheic flows, create and maintain diverse stream temperatures at with varying signals at unit (Arrigoni 2004), reach (10-1-101m) (Arrigoni 2004) and at whole river scales (O’Daniel 2005) in the Umatilla River, Oregon. Increasing evidence shows that multiple scales of hyporheic flows are common to CRB floodplains ((Baxter and Hauer 2000), (Ebersole 2003), (Poole and Berman 2001; Kasahara 2003). Although there is broad agreement that the hyporheic zone is vital to river ecosystems (Brunke and Gonser 1997) and hyporheic flows have the potential to influence whole river temperatures (Arrigoni 2004, O'Daniel et al. 2003), there has been no study that focuses on multi-scale expressions of hyporheic exchange and the resulting effects on water temperature and subsequent instream habitats. This limitation stems from two conditions: 1) a lack of recognition that hyporheic exchange is a critical and unconsidered pathway in fluvial landscapes; and 2) a poor understanding of the relationship between floodplain and watershed morphometry, river processes, hyporheic exchange and water temperature.



Related Project History

1998 EPA FLIR data collection and analysis in support of the Umatilla River Temperature TMDL
FLIR data was collected, processed and analyzed to inform the temperature TMDL for the Umatilla River.  The TMDL was completed in 2001 and was one of the first to include continuous stream temperatures,  While conducting the data analysis for this project, I observed several small, isolated cold-water areas that were associated with secondary channels, springbrooks and floodplain ponds.  The temperatures in several of these features was significantly lower than the surrounding waters.  This initial observation of heterogeneous water temperatures occurring in close spatial proximity lead to questions that were explored with Geoff Poole and further refined in the 2001 BPA Innovative Project.  



2001 BPA Innovative Project (2001-
The proposed research is designed to underpin an integrated remote sensing/ modeling approach to identification and assessment of salmonid habitat in alluvial floodplain rivers based on analysis of geomorphology and hydrologic function. Remote sensing data would be used to parameterize the model to assess water routing and mixing in the channel, floodplain, and hyporheic zone thus providing a mechanistic understanding of these complex hydrologic interactions and associated drivers of habitat diversity. Further research beyond the scope of this proposal would enable the model to incorporate dynamics of heat, nutrients, and/or carbon to investigate addition questions relevant to protection, restoration, or management of aquatic habitat.
In order to further our efforts toward this end, we are currently proposing research to meet the following specific objectives:  1) Identify and characterize three study sites on the Umatilla River, one each from the three general zones of high hyporheic potential identified by O’Daniel and Poole; 2) Develop a remote sensing approach to provide high-resolution, highly accurate digital elevation models (DEMs) to describe floodplain and channel geomorphology; 3) Refine and apply an existing hydrologic modeling system to use remotely-sensed DEMs to provide more detailed and realistic simulations of main-channel, floodplain, and hyporheic flow. Use simulation results to predict perirheic mixing and fluvial wetland complexes in targeted study reaches of the mainstem Umatilla River; 4) Use spectral analysis of remote sensing images to document patterns of perirheic mixing and associated geomorphic controls during a high-flow event on the Umatilla River.



2002 NASA DRDiSE Project
Data-Rich Decision Support Environment for Water Temperature Management in the Pacific Northwest

A multi-agency task force (National Marine Fisheries Service, U.S. Fish and Wildlife Service, Environmental Protection Agency, State and Tribal Governments) is focused on developing a new approach to water temperature management. Preliminary results from this effort (Water Temperature Criteria Technical Workgroup 2001) suggest that the most robust solutions to the problem are hampered by three limitations: 1) inadequate data to support critical decisions; 2) an incomplete assessment of the known influences on stream thermal dynamics; and 3) the scientific defensibility of the resulting water temperature management. These limitations arise in large part because current water quality monitoring programs are inadequate to address the multiple pathways of human influence on water temperature, the spatial and temporal variation in water temperature, and the range of natural dynamics that influence water temperature (Poole and Berman 2001; Poole et al. 2001).  We created a Data-Rich Decision Support Environment (DRDSE) for development, implementation, and monitoring of water temperatures. The DRDSE will help account for the high variability in stream systems, ecosystem processes, and thermal response. While we propose a new approach to developing and implementing water temperature management, the underlying data collection and analysis techniques upon which our approach is based are comprised of established and proven methodologies. Using new ecological paradigms, remotely sensed data, and an integrated temperature modeling approach, this proposal seeks to pilot a defensible, ecologically-based temperature standard that is protective of endangered salmonids, but recognizes the natural thermal diversity streams.