Sediment discharge due to rainfall-induced red clay erosion is a perennial problem in coastal environments. Conveyance of turbid waters to receiving coastal waters cause coral reefs to suffer intense environmental stress due to heavy sediment accumulation. Thus, there is a need to accurately quantify the amount of sediment delivered by given watershed system to adjacent coastal reef areas.
A rainfall event-based distributed hydrologic model for Todoroki watershed was developed utilizing data from remote sensing techniques implemented under a GIS-ready computational environment. In the formulation of the methods to physically describe the erosional process, emphasis was placed on role of vegetation and soil cover conditions on the overall spatial pattern of soil loss.
Field surveys are conducted in the study area in June to August 2000 to obtain vegetation and soil measurements necessary to support data parameterization in the remote sensing data analysis and to install instruments which gather continuous hydrologic data such as precipitation and sediment runoff intensities at the catchment scale.

This study provides a valuable visualization tool to assess the impact of anthropogenic activities to the overall status of overland erosion and quantitatively link potential stressor like sediments with decline of coral reefs at finer time scales during episodic, high discharge events.