Scientific Investigations Report 2009–5233
1 U.S. Geological Survey.
2 U.S. Environmental Protection Agency.
3 Consultant, Woodville, VA.
4 Hughes Corporation, Sioux Falls, SD.
5 Horizon Systems Corporation, Herndon, VA.
6 University of Texas at Austin.
Different methods for determining catchments (incremental drainage areas) for stream segments of the medium-resolution (1:100,000-scale) National Hydrography Dataset (NHD) were evaluated by the U.S. Geological Survey (USGS), in cooperation with the U.S. Environmental Protection Agency (USEPA). The NHD is a comprehensive set of digital spatial data that contains information about surface-water features (such as lakes, ponds, streams, and rivers) of the United States. The need for NHD catchments was driven primarily by the goal to estimate NHD streamflow and velocity to support water-quality modeling. The application of catchments for this purpose also demonstrates the broader value of NHD catchments for supporting landscape characterization and analysis.
Five catchment delineation methods were evaluated. Four of the methods use topographic information for the delineation of the NHD catchments. These methods include the Raster Seeding Method; two variants of a method first used in a USGS New England study—one used the Watershed Boundary Dataset (WBD) and the other did not—termed the “New England Methods”; and the Outlet Matching Method. For these topographically based methods, the elevation data source was the 30-meter (m) resolution National Elevation Dataset (NED), as this was the highest resolution available for the conterminous United States and Hawaii. The fifth method evaluated, the Thiessen Polygon Method, uses distance to the nearest NHD stream segments to determine catchment boundaries.
Catchments were generated using each method for NHD stream segments within six hydrologically and geographically distinct Subbasins to evaluate the applicability of the method across the United States. The five methods were evaluated by comparing the resulting catchments with the boundaries and the computed area measurements available from several verification datasets that were developed independently using manual methods.
The results of the evaluation indicated that the two New England Methods provided the most accurate catchment boundaries. The New England Method with the WBD provided the most accurate results. The time and cost to implement and apply these automated methods were also considered in ultimately selecting the methods used to produce NHD catchments for the conterminous United States and Hawaii.
This study was conducted by a joint USGS–USEPA team during the 2-year period that ended in September 2004. During the following 2-year period ending in the fall of 2006, the New England Methods were used to produce NHD catchments as part of a multiagency effort to generate the NHD streamflow and velocity estimates for a suite of integrated geospatial products known as “NHDPlus.”
First posted January 2010
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Johnston, C.M., Dewald, T.G., Bondelid, T.R., Worstell, B.B., McKay, L.D., Rea, Alan, Moore, R.B., and Goodall, J.L., 2009, Evaluation of catchment delineation methods for the medium-resolution National Hydrography Dataset: U.S. Geological Survey Scientific Investigations Report 2009–5233, 88 p. (Also available at http://pubs.usgs.gov/sir/2009/5233/.)
National Hydrography Dataset
Concept of National Hydrography Dataset Catchments
National Elevation Dataset
Elevation Derivatives for National Applications
Watershed Boundary Dataset
Catchment Delineation Methods
Raster Seeding Method
New England Method with Watershed Boundary Dataset
New England Method without Watershed Boundary Dataset
Outlet Matching Method
Thiessen Polygon Method
Testing the Catchment Delineation Methods
Basis for Comparison
Datasets Obtained for Verification in the Comparison Analysis
Boundaries from the Watershed Boundary Dataset
Coefficient of Areal Correspondence
Normalizing Coefficient of Areal Correspondence
Polygon-Area Percent Error
Cumulative Drainage-Area Analysis
Evaluation of Catchment Delineation Methods
Appendix. Detailed Discussion for each Study Subbasin