HR: 0800h
AN: B41B-0457    [Abstracts]
TI: Assessing Watershed Sensitivity to Minimize Peak Flow Modification due to Logging After Forest Disturbance
AU: * Weiler, M
EM: markus.weiler@ubc.ca
AF: University of British Columbia, Departments of Forest Resources Management and Geography, Vancouver, BC V6T 1Z4, Canada
AB: Forest cover is a key modifier of a watershed's peak flow regime. Where forest cover is reduced due to logging or natural disturbances such as fire and insect/disease outbreaks, peak flows are, in most cases, increased. Based on GIS data available for the entire province of British Columbia (BC), Canada, with its diverse climatic regimes, land cover and hydrologic processes, we developed a methodology that classifies the sensitivity of watersheds to peak flow modification based on input characteristics and hydrological runoff generation processes. The input model component uses climatic data to derive mean annual snowmelt and maximum rainfall rates for BC for each month at a 400m grid resolution. It calculates the time of occurrence of peak flow and the precipitation regime of a watershed: snowmelt-dominated, rainfall-dominated, and transitional. This allows mapping peak flow generating input for each 3rd order watershed in BC. The runoff generation model component delineates dominant peak flow producing hydrologic processes at the watershed level: channel interception, Hortonian Overland Flow, Saturation Overland Flow and Shallow Subsurface Flow. This delineation is based on a combination of factors such as land cover, relief, slope, aspect, drainage density, drainage pattern, and hillslope morphology. The model components are validated against provincial hydro-climatic data sets. Derived maps at 25m resolution are then used to classify the watershed into different peak flow regimes to derive a sensitivity rating for different disturbance scenarios. This rating is then incorporated into a framework to assess risks to infrastructure, drinking water, and fish habitat and to minimize peak flow modification by optimizing timing, extend and location of logging in watersheds.
UR: http://faculty.forestry.ubc.ca/weiler/
DE: 1632 Land cover change
DE: 1847 Modeling
DE: 1860 Streamflow
DE: 1879 Watershed
SC: Biogeosciences [B]
MN: 2007 Fall Meeting