Correlating Sub-Basin Sediment Fingerprints to Land Use in the.

Suspended sediment is the most common cause of stream impairment in the United States.  In an effort to reduce sediment loading, Total Maximum Daily Loads (TMDLS) have been developed for sediment and runoff control.  In order to implement a TMDL, a source assessment must be performed to identify sediment origin. Source assessments generally measure erosion in a basin as a method of identifying sediment provenance. This provides a misleading picture of sediment origin in that it does not account for sediment storage within the system. This study seeks to further our ability to directly determine sediment provenance by utilizing the sediment fingerprinting technique. Several sub basins of the North Fork Broad River (NFBR) are being sampled for suspended sediment and the sediment fingerprinting technique will be utilized in an  effort to determine hotspots of anthropogenic inputs of sediment within the basin. Potential sources fall into three categories 1: surface (pastures and forests) 2: stream banks 3: upland subsurface (dirt roads, construction sites). Three tracers are being used in the study, two proven and one experimental.  ¹³⁷C and ¹⁵N are utilized to discriminate between the three input categories listed. While these tracers have proven capable at discrimination between the three primary source categories, they are unable to discriminate between upland sub surface soils.  Fatty Acid Methyl Esters (FAME) will be utilized in an attempt to discriminate between different upland subsurface inputs (dirt roads and construction sites).  The End Member Mixing Model will be used to determine relative contributions. Currently, ¹⁵N and ¹³⁷CS data on 13 runoff events in two sub-basins indicate a two end member model with banks contributing 70% and pastures 30%.