Stormwater Reuse Opportunities and Effects on Urban Infrastructure Management; Review of Practices and Proposal of WinSLAMM Modeling

This presentation summarizes a Water Environment Research Foundation (WERF)/EPA funded project which aims to show how currently available models and other tools can be interactively used to calculate the benefits of stormwater beneficial uses. This project summarizes the lessons learned, including successes, from a wide variety of international stormwater beneficial use projects. Our goal was to identify features that can be applied to U.S. conditions. The report includes summaries of case studies from developing countries in both arid and wet climates, case studies from developed countries in areas where future water conservation is necessary to support continued growth, and from developed countries where sustainable use of natural resources is of high priority. Also reviewed are typical water quality conditions from different stormwater sources in urban areas and desirable (or regulated) water quality requirements for the use of this water for different applications. Water quality degradation associated with different storage options is also examined along with different water treatment options to meet the needed “finished” water quality before use. Guidance is provided on how to determine the amount of supplemental landscape irrigation needed from stored stormwater, and how to calculate needed tankage volumes for many locations in the U.S.The project calculates the beneficial use opportunities of stormwater, especially landscaping irrigation, in different areas of the country, using continuous stormwater models for the development of production functions for tankage volume alternatives. The project presents a method to evaluate or size water tanks needed to optimize the beneficial uses of stormwater. Irrigation of land on the homeowner's property was considered the beneficial use of most interest. Irrigation calculations rely on good evapotranspiration (ET) data, which is rare for urban settings. Guidance on plants that withstand a wide range of moisture conditions is also provided in order to maximize the use of the runoff water. Extensive appendices present monthly ET values for several hundred locations near urban areas in the U.S.