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BMPS
In undisturbed landscapes, stormwater runoff is part of the natural hydrologic cycle. Vegetation, soils, and a wide range of organisms filter, absorb, and use rainfall in their living processes. Evaporation and transpiration takes place. Excess precipitation infiltrates into groundwater and flows into surface waters, recharging aquifers and supporting aquatic life. The entire system is affected when the landscape is changed.
Pennsylvania’s Stormwater Management Program, as described in the PA DEP Stormwater BMP Manual, emphasizes a comprehensive total site design approach. Whether referred to as “Low Impact Development”, “Conservation Design”, or “Green Design”, this environmentally sensitive approach to site development and stormwater management aims to minimize the effect of development on water, land, and air resources.
The Comprehensive Stormwater Management Site Planning and Design Procedure described in the Manual provides a roadmap to determining the most appropriate solution for managing stormwater on a specific site. It is critical to utilize this Procedure or a similar process to develop a stormwater management plan that meets local regulations and aligns with the Commonwealth’s water quality and quantity goals. Stormwater best management practices (BMPs) are integral to the site planning and design process.
Stormwater BMPs are a suite of planning processes, development methodologies, and specific “structural” techniques designed to be used in combination to:
- Prevent disturbances to natural systems and hydrologic functions; and,
- Minimize the impacts of disturbances where they do occur.
Non-structural BMPs are a combination of design and planning techniques that preserve natural systems and hydrologic functions on a site. Non-Structural BMPs encourage the treatment, infiltration, evaporation, and transpiration of precipitation close to where it falls, while helping to maintain a more natural and functional landscape. The key distinction between Non-Structural BMPs and Structural BMPs is that the former are intended to prevent stormwater generation, while the focus of the latter is on mitigating unavoidable stormwater-related impacts.
