HYDROLOGIC MODELING OF LAND PROCESSES IN PUERTO-RICO USING REMOTELY-SENSED DATA

An integrated, multi-disciplinary effort to model land processes affec ting Mayaguez Bay in western Puerto Rico is described. A modeling stra tegy was developed to take advantage of remotely sensed data. The spat ial, interannual, and seasonal variability of sediment discharges to t he bay were also evaluated. Classified images of remotely sensed data revealed the spatial distribution and quantities of land use classes i n the region and aided in the discretization of the watershed into hom ogeneous regions. These regions were modeled using a geomorphic modeli ng technique based upon spatially averaged parameters. Simulation resu lts from the modeling effort compared favorably with observations at t wo locations within the watershed. Results showed that runoff and sedi ment loads from the area exhibit a marked seasonal trend and that defo rested areas located in the foothill regions of the watershed contribu te a disproportionate share of the sediment load to the bay. In years when rainfall distributions are uniformly distributed over the area, t he sediment yields may be up to 100 percent higher than years when the rainfall is concentrated in the heavily forested mountainous regions.