Using NEXRAD and Rain Gauge Precipitation Data for Hydrologic Simulation in a Catskill Mountain Watershed.

Spatially distributed precipitation data is a prerequisite for distributed hydrology and water quality modeling. This is often limited by the availability of sufficient number of precipitation gauges within a watershed that provide the desired spatial and temporal coverage. In the case of forested watersheds with dense tree cover this is further constrained by the availability of suitable sites for gauge installation and data collection. In this context next generation radar (NEXRAD) estimates of precipitation present a viable alternative with the necessary spatial and temporal resolution. In this study we use the Multisensor Precipitation Estimator (MPE) NEXRAD data developed by the National Weather Service (NWS) along with rain gauge data for hydrologic simulation in a Catskill watershed that is part of the New York City water supply system. Preliminary results indicate that incorporating NEXRAD data improved the total volume of stream flow simulated by the SWAT model during the study period (2006-2010). We also evaluated the impact of combining NEXRAD data with varying combinations of available rain gauge data within the study watershed.