PENNSYLVANIA STORMWATER BEST MANAGEMENT PRACTICES MANUAL INTRODUCTION CHAPTERS 1, 2 Bureau of Watershed Management DEP

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.

Manual Principles 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. 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;

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

Stormwater Management Program COMPREHENSIVE SW POLICY BMP Technical Manual NPDES Construction Permits Phase II MS4 Permits ACT 167 Planning Program Courtesy of PADEP

Acknowledgements SMOC-Stormwater experts. Interested stakeholders. 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