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VERIFICATION OF URBAN RUNOFF MODELS
Citation:
Hackett, D., J. Schenk, D. B. Crawford, S. Rangarajan, AND M K. Stinson*. VERIFICATION OF URBAN RUNOFF MODELS. Presented at National TMDL 2002 Science & Policy Conference, Phoenix, AZ, 11/13-16/2002.
Description:
Wet Weather Flow Models are used throughout the United States for evaluation of the sanitary, storm and combined sewer systems. Models are used for planning new systems or upgrading of existing systems to accommodate growth or to control undersirable overflows and associated water quality impacts. Models are also used for design of wet weather facilities including sizing of conveyance, storage facilities, pump stations and treatment plants. The challenges in selecting a model to perform evaluations include: 1) understanding the objective(s) to be accomplished 2) knowing the real world system being modeled (e.g., collections system representation, rainfall data, basin characteristics, etc.) and 3) having a working knowledge of a model's capabilities and features. Often the model is chosed with little available information related to the background processes involved in producing rainfall-runoff responses or conveyance through a collection system. A third party evaluation of the capabilities and performance of wet weather models would therefore provide a level of confidence in the model's background methods and processes that are not currently available to the majority of model users and permitters. Providing this performance data in an unbiased manner would facilitate the model selection and application process. A framework for generating this third party data is afforded by the Wet Weather Flow (WWF) Pilot, currently part of the Water Quality Protection Center, of the Environmental Technology Verification (ETV) Program. A brief overview of the verification program developed for urban runoff models will be presented. The focus for the remainder of this paper will be on the verification of a specific vendor's software, the XP-SWMM modeling system produced by XP-Software. This testing has been completed; the results are being reviewed, and may be added to the conclusions later.