Natural Resource Ecology Laboratory

Delta-Q and FOREST Cumulative Effects Models

Delta-Q and FOREST

Cumulative Effects Models:

Recent increases in geographic information systems, computing power, and field data are facilitating the development of spatially explicit, quasi-physically based models to more accurately assess cumulative watershed effects (CWEs). The goal is to develop a modular set of procedures that allows resource specialists to rapidly predict changes in runoff and sediment yields for watersheds ranging in size from approximately 10 to 100 km2.
As a first step, two modules are being developed to predict catchment-scale changes in runoff and surface erosion due to forest harvest, roads, and fires. With respect to runoff, the lack of paired-watershed studies in the Sierra means that management-induced changes in peak flows, median flows, and low flows are estimated from published values. Background and management-induced erosion rates are being obtained from a combination of literature values and field data collected by the authors from 1999-2002. The predicted changes in runoff are summed over the catchment being modeled, while the sediment model has procedures to deliver sediment from the hillslope to the stream network as a function of hillslope gradient, land cover, soils, and distance from the channel. Sediment will be routed through the stream network as a function of stream gradient, drainage area, and particle size.

(Post fire erosion - Schoonover Gulch, CO )

(Patch cuts - Coon Creek, WY)


To develop a model with the following characteristics:
  • spatially explicit modules to predict changes in runoff and sediment generation
  • a user-friendly model characterized by a sequential, menu-driven graphical user interface (GUI);
  • a modular approach that can be updated and expanded with improved or alternative predictive algorithms;
  • flexibility in allowing users to readily change input values.


DELTA-Q and FOREST are PC based models. They require an ESRI ArcGIS 8 or 9.x license to run correctly.

All GIS data layers must be ArcInfo coverages or grids.
All grids and coverages must be in same projection with units in meters.
All grids and coverages must be in the same workspace.
User must have write access to the workspace containing the coverages. A utility is included that will copy coverages between workspaces.
User needs computer permissions to install the model - see your system administrator with questions.


(South Platte River, CO)


Click here for installation instructions.

For detailed instructions see the documentation for Delta-Q and FOREST.

Download: Delta-Q and FOREST (Forest Erosion Simulation Tools)

Sample data (~20 mb) should only be used to become familiar with the model, not for reporting results. Many values were missing so they were fudged in order to test the model!