Water quality changes along hyporheic flow paths may have important effects on river water quality and aquatic habitat. Previous studies on the Williamette River, Oregon, showed that river water follows hyporheic flow paths through highly porous deposits created by river channel meandering. To determine water quality changes associated with hyporheic...
This paper describes the application of aerial photography and GIS technology to develop flexible and transferable methods for multi-spatial scale characterization and analysis of riparian corridors. Relationships between structural attributes of riparian corridors and indicators of stream ecological conditions are not well established. As part of a research project focused...
Little research has been directed toward determining the status and ecological role of riparian areas in agricultural landscapes of the Willamette Valley, Oregon. A research project has been designed to contribute to the development and evaluation of alternative future scenarios and to improve the basic understanding of the role of...
The Calapooia River, a major tributary of the Willamette River in western Oregon, is a watershed typical of many found in the Willamette Basin. Public and private forested lands occur in the steep Upper Zone of the watershed, mixed forest and agriculture lands are found in the Middle Zone, and...
The growing population of Oregon’s Willamette River Basin places an increasing demand on the basin’s surface waters. Watershed-scale research addressing spatial trends of dissolved nitrogen (DN) and its relationship with landuse and soil N dynamics, such as N mineralization, is sparse in the Willamette Basin. I measured DN along 124...
Red alder (Alnus rubra), a nitrogen(N)-fixing deciduous broadleaf tree, can strongly influence N
concentrations in western Oregon and Washington. We compiled a database of stream N and GIS-derived landscape
characteristics in order to examine geographic variation in N across the Oregon Coast Range. Basal area
of alder, expressed as a...
Full Text:
spatially variable occurrence of red
alder (Alnus rubra) (Wigington et al., 1998; Binkley
et al., 2004), an
Riparian ecosystems, through their unique positions in the agricultural landscape, have the potential to mitigate nutrient loading to streams. This study was conducted to gain a better understanding of N cycling in a poorly drained Grass Riparian Zone (GRZ) and adjacent Perennial Ryegrass seed Field (PRF) in the Willamette Valley,...
This work furthers the understanding of processes occurring in catchments that affect stream nitrate concentrations using two different approaches: a temporally intensive case study of three headwater catchments with varying land use (through storm event monitoring) and a spatially intensive study on the regional scale (through statistical modeling) of 1st-4th...
Projected intensification of drought as a result of climate change may reduce the capacity of streams to rear fish, exacerbating the challenge of recovering ESA-listed salmon populations. Without management intervention, some stocks will likely go extinct as stream drying and fragmentation reduce juvenile survival to unsustainable levels. To offset drought-related...
Agricultural practices, including tillage, fertilization, and residue management, can affect surface runoff, soil erosion, and nutrient cycling. These processes, in turn, may adversely affect (1) quality of aquatic resources as habitat for amphibians, fish, and invertebrates, (2) costs of treating surface and ground water to meet drinking water standards, and...