Tuesday, November 14, 2006

Spatial Variability in Sediment Yields: Influence of Basin Parameters.

Rajith Mukundan, David Radcliffe, and Karin Lichtenstein. Univ of Georgia, 3111 Miller Plant Sciences, Athens, GA 30602

The North Fork Broad River in Georgia was included in section 303(d) list of impaired waters for impacted biota and habitat. Sediment was determined to be the pollutant of concern. A research project has been initiated to study sediment sources and to model and evaluate the effect of best management practices (BMPs) on sediment loading. Flow and total suspended solids (TSS) data collected from the watershed outlet during the period from January 2005 to August 2006 were used for making rating curves for sediment load estimation. The rate of export of suspended sediment from the watershed was estimated to be 1555 kg ha-1 yr-1. Preliminary estimation of sediment loads in three sub-basins within the watershed shows variation among the sub-basins in terms of the sediment yields per unit land area. A closer look at the possible reasons for this discrepancy was attempted by considering the influence of basin parameters such as land use, soils, mean slope, mean elevation, basin relief, and precipitation. Spatially distributed basin parameter data can be extracted in a geographic information system (GIS) framework and statistically analyzed to estimate the degree of influence by each parameter. The influence of each basin parameter on sediment yield will be discussed.