Employing land-use schemes as a mitigation strategy for the water quality impacts of global climate change.

摘要

Currently, relatively little information is known about the use of land management options as a tool to adapt to the water quality impacts of global climate change. The goal of this dissertation is to investigate the combined impacts of land-use and climate changes on water quality in the Little Miami River (LMR) watershed. This project uses current and future land-use development plans from the counties comprising the LMR watershed to form a future land-use scenario for the watershed. Climate change is simulated using results from two prominent Global Circulation Models to develop four hypothetical climate scenarios. These scenarios simulate “worst-case” scenarios which depict the warm-dry and warm-wet events which can affect the hydrological cycle. The hydrological impacts of these climate scenarios, along with those of the future land-use changes, are modeled using the Soil and Water Assessment Tool (SWAT). Through this methodology, individual and combined impacts of the land-use and climate changes on water quality can be examined. This results indicate that the changes in runoff, nutrient, and sediment loads under future climate changes are large enough to require a significant planning response. In addition, low-density residential developments can result in higher water quality than agricultural land, when both soil type and land-use type are taken into consideration. Modeling results indicate that the nutrient enrichment problem in the watershed is due to an overabundance of phosphorus; sedimentation is also a problem. When land-use changes are implemented in light of the impending climate change, both phosphorus loads and sediment loads can be drastically decreased. Therefore, the use of land management schemes can be a powerful, flexible, and adaptive tool to mitigate the adverse water quality impacts of global climate change.