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National Stormwater Calculator: Low Impact Development Stormwater Control Cost Estimation
Citation:
Berner, J. National Stormwater Calculator: Low Impact Development Stormwater Control Cost Estimation. Building Blocks Green & Complete Streets, Central Falls, RI, May 10 - 11, 2017.
Impact/Purpose:
The National Stormwater Calculator is a planning level tool for assessing stormwater runoff reductions resulting from modeling the use of green infrastructure and low impact development practices for small urban sites throughout the USA. This presentation is intended to inform community stakeholders of Central Falls, RI about how to generally use the cost estimation module of the calculator.
Description:
Stormwater discharges continue to cause impairment of our Nation’s waterbodies. EPA has developed the National Stormwater Calculator (SWC) to help support local, state, and national stormwater management objectives to reduce runoff through infiltration and retention using green infrastructure practices as low impact development (LID) controls. The primary focus of the SWC is to inform site developers on how well they can meet a desired stormwater retention target with and without the use of green infrastructure. It can also be used by landscapers and homeowners. Platform. The SWC is a Windows-based desktop program that requires an internet connection. A mobile web application version that will be compatible with all operating systems is currently being developed and is expected to be released in the fall of 2017.Cost Module. An LID cost estimation module within the application allows planners and managers to evaluate LID controls based on comparison of regional and national project planning level cost estimates (capital and average annual maintenance) and predicted LID control performance. Cost estimation is accomplished based on user-identified size configuration of the LID control infrastructure and other key project and site-specific variables. This includes whether the project is being applied as part of new development or redevelopment and if there are existing site constraints.Climate Scenarios. The SWC allows users to consider how runoff may vary based both on historical weather and potential future climate. To better inform decisions, it is recommended that the user develop a range of SWC results with various assumptions about model inputs such as percent of impervious surface, soil type, sizing of green infrastructure, as well as historical weather and future climate scenarios. This presentation is intended to inform community stakeholders of Central Falls, RI about how to generally use the cost estimation module of the calculator.