Your tax-deductible donation helps protect our water and land.
Sign up for our e-news and stay up to date as we add new case studies, resources, and tools.
Stormwater Management: Non-structural BMPs
Non-structural BMPs focus on preserving open space, protecting natural systems, and incorporating existing landscape features such as wetlands and stream corridors into a site plan to manage stormwater at its source. Some focus on clustering and concentrating development, minimizing disturbed areas, and reducing the size of impervious areas. Those promoted in the PA DEP Stormwater BMP Manual reflect the ten “Principles”of comprehensive stormwater management:
- Managing stormwater as a resource;
- Preserving and utilizing existing natural features and systems;
- Managing stormwater as close to the source as possible;
- Sustaining the hydrologic balance of surface and ground water;
- Disconnecting, decentralizing and distributing sources and discharges;
- Slowing runoff down, and not speeding it up;
- Preventing potential water quality and quantity problems;
- Minimizing problems that cannot be avoided;
- Integrating stormwater management into the initial site design process; and
- Inspecting and maintaining all BMPs.
The Manual identifies several major categories of non-Structural BMPs, and outlines specific BMPs for each of these generalized areas to better define and improve their implementation. This list is intended to be refined and expanded as these types of stormwater management practices become more common throughout Pennsylvania.
A detailed discussion of Non-Structural BMPs can be found in Chapter 5 of the Stormwater BMP Manual.
5.4.1 Protect sensitive/special value features
To minimize stormwater impacts, land development should avoid affecting and encroaching upon areas with important natural stormwater functional values (floodplains, wetlands, riparian areas, drainageways, others) and with stormwater impact sensitivities (steep slopes, adjoining properties, others) wherever practicable. This avoidance should occur site-by-site and on an area wide basis. Development should not occur in areas where sensitive/special value resources exist so that their valuable natural functions are not lost, thereby doubling or tripling stormwater impacts. Resources may be weighted according to their functional values specific to their municipality and watershed context.
