Submitted to: Annual International SWAT Conference
Publication Type: Proceedings
Publication Acceptance Date: 5/22/2009
Publication Date: 8/5/2009
Citation: Sexton, A.M., Sadeghi, A.M., Srinivasan, R., Shirmohammadi, A., Zhang, Z. 2009. Comparison of flow calibration using NEXRAD and surface rain gauge data in ArcSWAT. In: Proceedings of the 2009 International Soil and Water Assessment Tool (SWAT) Conference, August 5-7, 2009, Boulder, Colorado. 2009 CDROM. Interpretive Summary:
Technical Abstract: The value of watershed-scale, water quality models to ecosystem management is increasingly evident as more programs adopt these tools to help assess the effectiveness of different management scenarios on the environment. The USDA-Conservation Effects Assessment Project (CEAP) is one such program which was established to quantify the environmental benefits from conservation practices implemented under USDA conservation programs. The Choptank River watershed, located in Maryland on the Eastern Shore of the Chesapeake Bay, is a special emphasis watershed under the CEAP program. Several of its tributaries have been identified as “impaired waters” under Section 303(d) of the Federal Clean Water Act due to high levels of nutrients and sediments. The Soil and Water Assessment Tool (SWAT) was utilized to build a model for the German Branch (GB) watershed (~50 km2), a non-tidal tributary basin of the Choptank River. The overall goal of the project is to determine the effectiveness of cover crop programs to reduce nutrient loadings to the Choptank River; however, the initial steps to build the GB model are discussed here. Climate is the driving force of any water quality model; therefore effort was put into assessing the effects of alternative sources of climate data. Both surface rain gauge measurements and Next Generation Weather Radar (NEXRAD) precipitation data were used to determine any significant differences in model performance. Sensitivity, calibration, and validation analyses were conducted on the hydrology component of the GB model. The optimal water balance obtained in this study is an essential precursor to acquiring realistic sediment and nutrient results in forthcoming GB modeling efforts.