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Pennsylvania’s Stormwater Best Management Practices Manual aims to improve water quality and resources through effective stormwater management techniques. It emphasizes prevention and mitigation strategies, integration into site design, and maintenance of BMPs.
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PENNSYLVANIA STORMWATERBEST MANAGEMENT PRACTICES MANUAL Bureau of Watershed Management DEP INTRODUCTION CHAPTERS 1, 2
Pennsylvania’s Stormwater Best Management Practices Manual • The manual includes: • Performance guidelines & standards. • An inventory of proven BMPs and a process for planning and implementation. • Technical references of planning concepts and design standards that will satisfy Pennsylvania’s regulatory requirements and stormwater management policies when properly tailored and applied to local site conditions.
Introduction The manual is intended to be a tool to achieve the regulatory standard to protect, maintain, and improve the Commonwealth’s water resources through comprehensive site planning and BMP design guidance, while allowing for the continued growth and development of Pennsylvania.
Purpose • To Improve Stormwater Management throughout Pennsylvania. • Emphasis on Water Quality and Water Resources. • Describes a “new” Stormwater Management approach of prevention first and then mitigation.
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; Inspecting and maintaining all BMPs. Manual Principles
Stormwater Management • Relationship Land Use and Water • Integrated Approach • Comprehensive stormwater management planning. • Emphasizes reduction of impacts from development and other activities. • Manage Stormwater: • Volume • Water Quality • Peak Rate • Groundwater Recharge • Stream Impacts
Stormwater Management Standard • Post construction stormwater runoff volume, rate and quality should mimic pre-construction stormwater runoff volume, rate and quality to the maximum extent possible. • In Special Protection Waters – There should be no measurable change in post construction stormwater runoff volume, rate and quality. • In Waters other than Special Protection –Any change in post construction stormwater runoff volume, rate and quality shall not impair designated uses.
Stormwater Management Approach • First, prevent or minimize stormwater problems through comprehensive planning and development techniques, and • Second, to mitigate any remaining potential problems by employing structural and non-structural BMPs.
Stormwater Management • Federal Clean Water Act – 1972 • Pennsylvania Clean Streams Law - 1937 • PA Stormwater Management Act – 1978 (Act 167) • State and Federal Regulations • NPDES Post-Construction Stormwater Management Plans • Municipal Zoning and Ordinances
ACT 167 Planning Program COMPREHENSIVE SW POLICY NPDES Phase II MS4 Permits NPDES Construction Permits BMP Technical Manual Stormwater Management Program Courtesy of PADEP
Acknowledgements • SMOC-Stormwater experts. • Represent federal, state, and local government agencies, environmental groups, planners, land developers, and academia. • Interested stakeholders. • Public focus group meetings. • Public comment period.
Chapter 2 • Making the Case for Stormwater Management • Stormwater Problems • Hydrologic Cycle
Stormwater Problems • Large vs. Small Storm Events • Afterthought vs. Forethought • Generic Site Design vs. Customized Design
Land and Water Relationship • Hydrologic Cycle. • Pennsylvania Rainfall: Avg. 36” to 44”. • Impacts of Development and Impervious Surfaces. • Water and Environmental Quality. • Pennsylvania Watersheds, Soils, Geology.
Success Begins With Planning • Site Analysis • Evaluate Soils • Topography • Hydrology • Receiving water, wetlands • Know/Evaluate Constraints and Opportunities • Carbonate • Mining • Glaciated soils • Locate Stormwater “in the right place”
Additional Site Planning Considerations • T&E,Critical Habitat,Sensitive Species • Riparian Buffers, Natural Drainage • Historical/Archaeological • Aesthetics/Scenic • Other Special Value Areas
How stormwater is managed on a site-by-site basis affects entire Watershed