Erway, M. M. Dynamac Corp., morrison@mail.cor.epa.gov
Landers, D. M. USEPA, NHEERL, Western Ecology Division, landers@mail.cor.epa.gov
VanSickle, J. USEPA, NHEERL, Western Ecology Division, johnv@mail.cor.epa.gov
Trobaugh, D. USEPA, NHEERL, Western Ecology Division, trobaugh@mail.cor.epa.gov

 
PHYSICO-CHEMICAL CHARACTERISTICS AND RELATIONSHIPS OF OFF-CHANNEL HABITATS OF THE WILLAMETTE RIVER, OREGON
 
Off-channel habitats of large river systems include features such as alcoves or parapotamons, which are backwater areas with the upstream end closed to main channel surface flow. These lentic areas extend into the flood plain contributing habitat diversity to the river, each possessing a unique connectivity to the river. About 80% of the off-channel habitat in the Willamette River in Oregon was lost as the river was channelized and flows were regulated with dams. We began to investigate the ecological function these habitats provide to large river ecosystems in the summer of 1997. Sixteen alcoves in a 65 km reach of the river were sampled from once to several times per year for a variety of parameters. In this poster, we analyze the water chemistry results to determine the strongest indicators of the type of connectivity to the main channel. We then compare those indicators with measurements of potential periphyton production to explore the relationships between productivity, connectivity to the main channel, and water chemistry, including nutrient levels. These relationships are then used to characterize off-channel habitats into functional groups to understand the contribution these habitats provide to the riverine ecosystem.
 
Day: Tuesday, Feb. 2
Time: Poster
Location: Sweeney Center
 
Code: SS47TU0462S