195-11 Potential Impact of Climate Change On Soil Erosion and Sediment Yield In a New York City Water Supply Watershed.



Tuesday, October 18, 2011: 10:50 AM
Henry Gonzalez Convention Center, Room 007B, River Level

Rajith Mukundan1, Soni Pradhanang1, Elliot Schneiderman2, Donald Pierson2, Aavudai Anandhi1, Mark Zion2, Adao Matonse1 and Tammo Steenhuis3, (1)City University of New York, Kingston, NY
(2)New York City DEP, Kingston, NY
(3)Biological and Environmental Engineering, Cornell University, Ithaca, NY
High suspended sediment loads and the resulting turbidity exert an important control on the use of surface waters for water supply and other designated uses. Changes in fluvial sediment loads influence material fluxes, aquatic geochemistry, water quality, channel morphology, and aquatic habitats. Therefore, quantifying spatial and temporal patterns in sediment loads is important both for understanding and predicting soil erosion and sediment transport processes as well as watershed-scale management of sediment and associated pollutants. A case study from the 891 km2 Cannonsville watershed, one of the major watersheds in the New York City water supply system is presented. The objective of this study was to apply SWAT-WB, a physically based semi-distributed model to identify suspended sediment generating source areas under current conditions and to simulate potential climate change impacts on soil erosion and suspended sediment yield in the study watershed for a set of future climate scenarios representative of the period 2081-2100. Future scenarios developed using nine global climate model (GCM) simulations indicate a sharp increase in the annual rates of soil erosion although a similar result in sediment yield at the watershed outlet was not evident. Future climate related changes in soil erosion and sediment yield appeared more significant in the winter due to a shift in the timing of snowmelt and also due to a decrease in the proportion of precipitation received as snow. Although an increase in future summer precipitation was predicted, soil erosion and sediment yield appeared to decrease owing to an increase in soil moisture deficit and a decrease in water yield due to increased evapotranspiration.
See more from this Division: ASA Section: Climatology & Modeling
See more from this Session: Modeling Processes of Plant and Soil Systems Under Current and Future Climate: I