Case study: evaluation of streamflow partitioning methods

Understanding water flow and its relative quantities through different pathways is vital for watershed management. Like many problems in hydrology, numbers of methods have been proposed for streamflow partitioning. Five methods were identified as being the most relevant and least input intensive. This study tested performance of these methods against separately measured surface and subsurface flow data from the coastal plain physiographic region of the southeastern United States. Separately measured surface and subsurface flow were collected for 12 years (1970-1981) in a field scale watershed by the Southeast Watershed Research Laboratory of the USDA-Agricultural Research Service. Results of comparative analysis indicated that Method IV performed the best. Results also indicated that accuracy of this method is highly dependent upon the proper estimation of the 'fraction coefficient' that is based on many physical and hydrologic characteristics of the watershed. This study concluded that deterministic/empirical methods such as Boughton's Method IV, require proper parameter value for increased accuracy. DOI: 10.1061/(ASCE)IR.1943-4774.0000093 CE Database subject headings: Subsurface flow; Overland flow; Base flow; Streamflow; Case studies.