The Maryland Legislature enacted the Stormwater Management Act of 2007 which established stringent requirements to implement Environmental Site Design (ESD) to the Maximum Extent Practicable (MEP). The Maryland Department of Environment (MDE) subsequently released regulations and design guidance that local stormwater authorities are required to implement through local ordinance by May 4, 2010.
A major implementation issue is how will designers demonstrate (and plan reviewers verify) that a stormwater plan actually achieves the ESD to MEP criterion. This is an important issue since ESD compliance at each development or redevelopment site requires progressive and incremental accounting of the effect of better site design, alternative surfaces, disconnection credits and micro ESD practices on post development hydrology. This spreadsheet tool and users guide was created to fill the gap and provide a common and unified basis for effective local ESD design and plan review.