SUDA Tip: Configure Multiple Land Use in Catchments

When a catchment is created in SUDA, a feature definition is assigned to the catchment.

This feature definition will assign symbology to the catchment feature, (red in this example) and also assigns the run-off coefficient to the catchment.

However, in most cases the runoff coefficient needs to be weighted based on the relative percentages of different types of land use within the catchment. To accomplish this, in properties change the Area Defined By property from Single Area to Multiple Subareas.

For each subarea, entire the percentage of the total area and the desired runoff coefficient corresponding to that land use type. A weighted average is computed from these numbers and used for the runoff calculations. Note: There are no tools for automatically determining the percentages based on global land use shapes, as some GEOPAK Drainage designers were accustomed.


Robert Garrett

Robert has over 25 years experience as a practicing engineer and is licensed in the State of Tennessee. After graduating from Tennessee Technological University, Robert worked for the Mississippi State Highway Department, Bridge Design Division. Then he spent 12 years with the Tennessee Department of Transportation in the Roadway Design Office and later served as Regional Manager in the Design Survey Office.From 2000 to 2006, Robert worked for Robert G Campbell and Associates in Knoxville, TN where responsibilities included roadway, site, and utilities design projects.Joining Bentley Systems in March 2006, Robert wrote specifications & documentation for software development. Duties included testing, customer feedback and ensuring the products met the needs of the civil engineering user base. He also developed training material for education both internally to Bentley and for outside organizations. He served as Product Manager for Utilities Products, including the new OpenRoads Subsurface Utilities Design and Analysis software. Robert also provided guidance and implementation services for new technologies.He is a frequent presenter and trainer at user conferences.

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