Simulations of watershed response to land use and climate change in the Saugahatchee Creek Watershed using the WARMF model

Abstract

During recent years, land surfaces have been markedly transformed with artificial land cover limiting natural forests, accompanied by urbanization. The atmospheric concentration of greenhouse gases is believed to be increasing, thereby leading to anthropogenic climate change. It is very important, from watershed management point of view, to know how these alterations would affect water resources. In this study, we have tested the ability of a watershed model WARMF to simulate flow and water quality in the Saugahatchee Creek Watershed in Alabama and applied the developed model to assess the impact due to historical land use change and potential future climate change. Surface water temperature, dissolved oxygen, total phosphorus, total nitrogen, and chlorophyll-a concentrations were simulated along with flow at the watershed outlet. Based on model simulation, historical land use changes from 1991 to 2008 show rising pattern in nutrient levels and algal mass depleting water quality in the Saugahatchee Creek. Future climate for the 21st century, derived from HadCM3 A2 and B2 emission scenarios, were downscaled to local watershed scale for impact analysis. Surface water temperature is projected to increase, mostly in summer and dissolved oxygen concentration is projected to decrease. Both HadCM3 scenarios’ output predicted decrease in flow in the 21st century. Nutrient concentration increased corresponding to low flow. These results under different land use and climate change scenarios can be useful information for watershed planning and management decision.