INTRODUCTION

Sediment is the single most important water quality problem and the largest contributor by volume of non-point source pollution in the United States (Neary et al. 1988). About 17% of the water bodies in the United States are listed for sediment problem (Sediment TMDL technical advisory group, 2002). Section 303(d) of the 1972 Clean Water Act (CWA) requires states to identify water bodies that do not meet the federal standards for their designated uses. However, even after thirty years of pollution control efforts, the best way to identify the source of sediment in streams and managing it is still a topic for discussion. Monitoring the streams for turbidity is a laborious task and there is every possibility of missing a critical sediment source area as sampling of streams is usually done from random locations. Moreover synoptic sampling is not always possible when the size of the watershed under study is large. The North Fork Broad River, one of the last free flowing rivers in Georgia is one of the streams with high sediment loads.

Remote sensing technology offers an effective tool in identifying the critical sediment source areas in an impaired stream or river segment and helps prioritize sediment control measures. Satellite remote sensing has limitations when the size of the stream is small. However, aerial photography can cater such needs by its possibility of manipulating the image resolution by controlling the flying height of the aircraft and obtain images of sub-meter resolution. Also remote sensing has the advantage of acquiring information from areas or sections of stream/river that are normally difficult to access.

For details click "Estimating Suspended Sediment Concentration in Streams Using High Resolution Aerial Photography"