HR: 0800h
AN: H51C-1154    [Abstracts]
TI: Predicting Cumulative Watershed Effects using Spatially Explicit Models
AU: * MacDonald, L H
EM: leemac@cnr.colostate.edu
AF: Department of Forest, Rangeland and Watershed Stewardship, Colorado State University, Fort Collins, CO 80523 United States
AU: Litschert, S
EM: sam@cnr.colostate.edu
AF: Department of Geosciences, Colorado State University, Fort Collins, CO 80523 United States
AB: Cumulative watershed effects /(CWEs/) result from the combined effects of land disturbances distributed over both space and time. They are of concern because changes in flow and sediment yields can adversely affect aquatic habitat, channel morphology, water yields, and water quality. The assessment procedures currently used by agencies such as the U.S. Forest Service generally rely on a lumped approach to quantify disturbance, despite the widespread recognition that site conditions and location do matter! The overall goal of our work is to develop spatially-explicit models to quantify changes in flow and sediment yields. Key objectives include: use of readily available GIS data; ease of use for resource managers with minimal GIS experience; modularity so that models can be added or updated; and allowing users to select the models and values for key parameters. The DeltaQ model calculates changes in peak, median, and low flows due to forest management activities and fires. Inputs include GIS data with disturbance polygons, an initial change in flow rate, and the time to recovery. Data from paired watershed studies are provided to help guide the user. The initial version of FORest Erosion Simulation Tools /(FOREST/) calculates sediment production from forest harvest, fires, and unpaved roads. Additional modules are being developed to deliver this sediment to the stream channel and route it to downstream locations. In accordance with our objectives, the user can predict sediment production rates using different empirical equations, assign an initial sediment production rate and a specified linear recovery period, or develop a look-up table based on local knowledge, published values, or data from other models such as WEPP. The required GIS layers vary according to the model/(s/) selected, but generally include past disturbances /(e.g., fires and timber harvest/), roads, and elevation. Outputs include GIS layers and text files that can be subjected to additional analyses. Both DeltaQ and FOREST will be demonstrated and can be downloaded at: http://www.cnr.colostate.edu/frws/people/faculty/macdonald/macdonald/model.htm.
DE: 1899 General or miscellaneous
DE: 1803 Anthropogenic effects
DE: 1821 Floods
DE: 1824 Geomorphology (1625)
DE: 1860 Runoff and streamflow
SC: Hydrology [H]
MN: 2004 AGU Fall Meeting