The Urban Drainage and Flood Control District (UDFCD) maintains an ALERT gauging network, for real-time monitoring of rainfall, and operates a Flash Flood Prediction (FFP) Program, to forecast rainfall events up to 24 hours in advance, within the Denver metropolitan area. The Program Meteorologists communicate directly with area emergency management and public works agencies to prepare for and assess flash flood events. Spatially comprehensive rainfall estimates that are both timely and accurate are critical in this mission, to determine the level of threat in real-time. UDFCD is contracting with Leonard Rice Engineers, Inc to evaluate the use of rainfall data in real-time runoff models, simplified versions of the UDFCD master plan models.

Weather Decision Technologies (WDT) Inc. provides UDFCD rainfall estimates that are automatically derived from NEXRAD Level II mosaicked radar data and adjusted using the ALERT rain gauge data. These data are provided in Geographic Information System (GIS) format in real-time on a high-resolution 1 km grid. Traditionally FFP Program Meteorologists have used NWS single site radar data in conjunction with point ALERT data to estimate basin rainfall and communicate the potential flash flood threat with local agencies. During the 2007 FFP Program, WDT integrated the ALERT rain gauge data into their high resolution gridded radar rainfall mosaics, updated every 15 minutes. Both the radar-only Quantitative Precipitation Estimates (QPE) using multiple radars and the gauge-adjusted QPE products were provided. In 2008, WDT introduced a basin averaged product using delineated basins provided by the UDFCD

Leonard Rice Engineers, Inc hosts real-time runoff models for select basins within the UDFCD area. In the past, these models were completely driven by ALERT rainfall data. During 2008, the models were also tested using the WDT basin averaged QPE products. The output of the models included web-based tables and graphs.

This paper will be to discuss the gauge-adjusted radar QPE and basin averaged rainfall techniques, the integration of QPE products in local flash flood prediction and basin modeling and future plans to make this information more widely accessible via a web-based application.