Climate change vulnerability assessment and adaptation strategies through best management practices

Abstract

There is a growing scientific consensus on climate change and its impact on catchment scale hydrologic and water quality processes. Therefore, it is not only important to understand the impact of climate change but also necessary to formulate adaptation strategies to negate the effect of climate change. To this end, we have developed a hydrologic modeling framework (Soil and Water Assessment Tool) concomitant with Analytical Hierarchical Process (AHP) to develop individual as well as composite climate vulnerability index in a Southern New Jersey Watershed. Three agricultural BMPs including cover crop, filter strip, and no till were examined to determine their ability to negate the climate change impact on water fluxes and water quality in the watershed. Downscaled projected temperature and precipitation from six General Circulation Models (GCMs) for moderate and high emission scenarios (RCP-4.5 and 8.5, respectively) from the latest suite of Coupled Model Intercomparison Project Phase 5 (CMIP5) were incorporated in to the hydrologic model.Overall, results suggested an increase in temperature and precipitation under climate change scenarios leading to rise in surface runoff, streamflow, sediment and TP load relative to baseline scenario. Highly vulnerable areas to flooding, sedimentation and eutrophication under climate change using AHP framework were standout from other types of vulnerable areas in the watershed due to presence of excess impervious surface, higher percentage of agricultural lands, and increased sediment and organic phosphorus, respectively. When agricultural BMPs were implemented in corn and soybean fields located inside critical source areas (CSAs) under climate change scenarios, BMPs showed little to no effect towards reduction of water fluxes while they reduced maximum 2% and 12% of sediment and TP, respectively, compared to no BMP under climate change scenario. Further, as the BMP were incorporated in all corn and soybean fields in the watershed, the maximum sediment and TP reduction increased to 8% and 44%, respectively. The study outcomes suggests that climate change will increase the water fluxes as well as pollution load in the watershed, however, BMPs can be used to negate the water quality impact due to climate change.