Comparison of Headwater Stream Origin Determination Methods

Abstract

Abstract Carr, John David. Master of Natural Resources Spatial Information Systems Technical Option. Comparison of Headwater Stream Origin Determination Methods.

Water Quality in North Carolina is being negatively impacted by sedimentation pollution and nutrient loading. Riparian Buffer Rules (RBRs) have been adopted in many watersheds to abate these impacts. USGS 1:24,000 topographic maps and USDA County Soil Survey maps are the planning tools used to deploy RBR regulations to the regulated community. Errors in the approximate depiction of streams are known to exist on the USGS 1:24,000 topographic maps. Thirty-two stream origins were delineated using N.C. Division of Water Quality Stream Classification Method on the 514-hectare Harris Research Tract (HRT) located in southwest Wake County, North Carolina. The most recent USGS 1:24,000 topographic map of this area approximately depicts ten streams on the HRT. Geographic Information System (GIS) analysis techniques were used to extract stream origin predictions form Aerial Photography, Digital Raster Graphic, Digital Line Graphic, Digital Elevation Model, and Light Detection and Ranging (LIDAR) data for the Harris Research Tract. The stream origin predictions extracted from each data layer were compared to the thirty-two stream origins located in the field. Difference in Euclidean distance was used to evaluate how well the predicted stream origins matched the thirty-two stream origins located in the field. The stream origin data generated using LIDAR more closely matched actual findings in the field than all other data layers tested. Technological advances in high resolution digital elevation data and terrain analysis software could potentially be used to improve the approximate depiction of streams on the USGS 1:24,000 topographic map.