Previous research has indicated that considerable amounts of finely divided slash accumulate in small mountain streams following timber harvesting. The subsequent biological decomposition of this organic matter can result i.n the reduction of dissolved oxygen (DO) concentration to levels as low as 0.6 ppm. These DO levels are lethal
to...
Grain-size distributions of gravels transported as bedload in Oak Creek, Oregon,
show systematic variations with changing flow discharges. At low discharges the gravel
distributions are nearly symmetrical and Gaussian. As discharges increase, the
distributions become more skewed and follow the ideal Rosin distribution. The patterns of
variations are established by...
The incipient motion of sediment particles in gravel-bed
rivers is a very important process. It represents the
difference between bed stability and bed mobility. A field
study was conducted in Oak Creek, Oregon to investigate
incipient motion of individual particles in gravel-bed
streams. Investigation was also made of the incipient...
The importance of active-entry drift at a community-scale
was evaluated by testing whether the placement of wood
in streams affected the abundance of Baetis spp. mayflies in
drift. Baetis were chosen because they use drift as a
behavioral strategy and are important in salmonid diets. The
density of woody debris...
Pre-flood (1995), and post-flood (1996) channel stability surveys were conducted on 22 reaches along Oak Creek, Benton County, Oregon in an effort to note if the flood of February 1996 altered the channel and if the channel stability survey that was being used accurately predicted the channels resistance to change...
I evaluated the response of the federally listed endangered plant species Bradshaw's desert parsley (Lomatium bradshawii) to livestock grazing and small mammal depredation at Oak Creek, Linn County, Oregon, 1997-1998. I established six study blocks (three each in wooded and herbaceous pastures) with plots in each block randomly assigned to...
Unpaved roads are sources of chronic sediment in forested watersheds. Bare soil on roads is exposed to erosion from rainfall and runoff Published research on sediment production from forest roads focuses primarily on road characteristics. Since water drives the mechanics of sediment transport, hydrologic variables should correlate with sediment production....
The management of existing forest road systems is an issue of growing importance and public debate. Roads can alter the hydrologic processes in a watershed especially at stream crossing culverts where road ditches channel runoff directly into the stream. The objective of this study was to determine how surface runoff...
The impact of forest roads on the hydrology of forested watersheds has long been studied. While forest roads have been reported to alter storm runoff at the road segment scale, the potential for changes to be detectable at the small watershed scale has been debated. The purpose of this study...
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...