Cary, Richard Holland
MetadataShow full item record
Investigating storm runoff generation in watersheds is an area of ongoing hydrologic research. Geochemical tracer studies, such as static end-member mixing analysis (EMMA) and hysteresis loop analysis, have been used to evaluate these processes. We propose a new method called “Dynamic EMMA” (DEMMA) that incorporates both hysteresis loops and geochemical tracer studies to quantify runoff contributions from watershed flow pathways during a storm. This approach involves estimating relative tracer concentrations of four end-members, along with estimating the percentage of total stream discharge from each end-member. The method has been applied to storms from a 22 year dataset from Panola Mountain Research Watershed (PMRW), Georgia. Using DEMMA, two distinct watershed responses to rain events have been identified at PMRW, one where hysteresis rotation is clockwise, and another where the rotation is counter-clockwise. These responses appear to be related to a threshold of approximately 50 mm of total rain per storm.