Watersheds--Florida

Watershed delineations in low topographic relief landscapes with canal networks require hydrography. This hypothesis was tested by utilizing digital elevation models (DEMs). Seven DEMs were processed using two automated delineation methods. Both methods include filling of localized sinks, but an enhanced method incorporated incremental "tipping" to provide flow direction. In two watersheds studied, DEMs with only topography delineated watersheds within 24% and 84% of the manual delineation. With the addition of hydrography, including canals, both watersheds were delineated to within 85% and 92% of the manual delineation. Contrary to the assumption that tipping would improve delineation, tipping decreased the delineated area by removing a water flow path. Based on this research, DEM input data and delineation method strongly influence automated watershed delineations in low relief conditions.

Like so many natural areas in south Florida, the Dupuis Reserves' landscape has gone through extreme alteration due to numerous cultural activities. Activities including drainage, cattle ranching, and citrus farming have altered the reserves natural hydrology causing the formation of several watersheds. This hydrologic alteration has caused the once homogenous ecosystem to fragment into two separate landscapes: one dominated by drainage and human impact while the other remains in a relatively natural state. This study will attempt to determine, with the use of remote sensing, geographic information systems and digital image classifications if culturally derived watersheds cause significant change in the spectral signatures of vegetation. Results indicate that when the study site is sectioned along culturally derived watersheds, classification accuracy is significantly improved.