Evaluating the Slope‐Area Method to Accurately Identify Stream Channel Heads in Three Physiographic Regions |
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| Authors: | Burak Avcioglu Christopher J Anderson Latif Kalin |
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| Affiliation: | 1. Republic of Turkey Ministry of Forestry and Water Affairs, Ankara, Turkey;2. School of Forestry and Wildlife Sciences, Auburn University, Auburn, Alabama |
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| Abstract: | Estimation of stream channel heads is an important task since ephemeral channels play a significant role in the transport of sediment and materials to perennial streams. The slope‐area method utilizes digital elevation model (DEM) and related information to develop slope‐area threshold relationships used to estimate the position of channel heads in the watershed. A total of 162 stream channel heads were mapped across the three physiographic regions of Alabama, including the Southwestern Appalachians (51), Piedmont/Ridge and Valley (61), and Coastal Plains (51). Using Geographic Information System and DEM, the local slope and drainage area for each mapped channel head was calculated and region‐specific models were developed and evaluated. Results demonstrated the local slope and drainage area had an inverse and strong correlation in the Piedmont/Ridge and Valley region (r2 = 0.71) and the Southwestern Appalachian region (r2 = 0.61). Among three physiographic regions, the weakest correlation was observed in the Coastal Plain region (r2 = 0.45). By comparing the locations of modeled channel heads to those located in the field, calculated reliability and sensitivity indices indicated model accuracy and reliance were weak to moderate. However, the slope‐area method helped define the upstream boundaries of a more detailed channel network than that derived from the 1:24,000‐scale National Hydrography Dataset, which is commonly used for planning and regulatory purposes. |
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| Keywords: | headwaters river networks Geographic Information Systems stream channel head slope‐area model channel initiation Alabama |
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