HR: 0800h
AN: H51D-1182    [Abstracts]
TI: Total Runoff From Roads as an Index for Potential Changes in Watershed Hydrology
AU: * Simmons, A N
EM: amy.simmons@oregonstate.edu
AF: Oregon State University Department of Forest Engineering, Peavy Hall Rm. 215 , Corvallis, OR 97331 United States
AU: Skaugset, A E
EM: arne.skaugset@oregonstate.edu
AF: Oregon State University Department of Forest Engineering, Peavy Hall Rm. 215 , Corvallis, OR 97331 United States
AB: Known impacts of forest roads on watersheds include altered magnitude and timing of peak flows. The effect of the contribution of flow from roadside ditches on a watershed is less well understood. Roadside ditches channel Hortonian overland flow that falls on road surfaces. Also, roadside ditches intercept and channel subsurface flow. The objective of this study was to determine the magnitude of the surface runoff from roads that might alter the hydrology of a roaded watershed. The study was carried out in an 824 ha forested watershed in the foothills of the Oregon Coast Range in the MacDonald-Dunn Research Forest approximately 5 km west of Corvallis, Oregon. In the Oak Creek Watershed, there are 4.57 km of road and 4.87 km of stream resulting in a drainage density of 0.64 km/km$^{2}$ and a road density of 0.6 km/km$^{2}$. There are 98 drainage structures on the roads in the Oak Creek Watershed. Twenty-three of the drainage structures are stream-crossing culverts and the balance are cross-drain culverts. Discharge was measured at all of the drainage structures and at the outlet of the watershed from October 2002 through May 2003 for five storms. The hydrology of the roads in the Oak Creek Watershed is highly variable in space and time. Road runoff was measured and expressed as a proportion of total watershed runoff. This metric allows an insight into the potential for the road system to alter watershed hydrology.
DE: 1803 Anthropogenic effects
DE: 1860 Runoff and streamflow
SC: Hydrology [H]
MN: 2004 AGU Fall Meeting