Estimation of Urban Growth Impact on River Ecosystems through Remote Sensing and GIS Techniques: A Case Study of the Cahaba Watershed Area

Landscape transformations are the most widespread and potential threat to watershed ecosystems. Different land transformations such as urbanization, deforestation, and expansion of agricultural areas impact land cover, hydrology, and terrestrial and aquatic linkages in the watershed. The Cahaba River, located in Alabama, is among the most biologically diverse rivers in North America, and supplies water to 20% of Alabama residents. The largest metropolitan area in Alabama, the city of Birmingham, is found within the upper sub-watersheds of the Cahaba River watershed. As the city and its population grow there has also been an increase in environmental concern over the recent declines of aquatic species, a rise in endangered wildlife, and issues of water quality, in particular surface runoff and sedimentation. The main objective of this research is to assess the land use and land cover changes and their impacts on the biodiversity and different aquatic habitat species on the Cahaba Watershed. To investigate the land cover changes, LandSAT 5 TM scenes from 2001, 2006 and 2010 were used to derive vegetation cover changes and apply spatio-temporal analyses. The second objective of the study is to establish a GIS model to integrate the social and physical factors impacting the biodiversity with remotely sensed data. The final objective is to apply statistical analyses to investigate the habitat degradation with results of the GIS model. Findings and end products will be vital to policy makers for the Cahaba River Society, City of Birmingham, and Alabama Department of Environmental Management in development of conservation strategies and new land-use plans pertaining to the Cahaba River watershed.