1. Pennsylvania Stormwater Best Management Practices
  2. Manual
  3. Chapter 1
  4. Introduction and Purpose
  5. Chapter 1 Introduction and Purpose
    1. 1.1 Purpose of this Manual………………………………………………………………1
    2. 1.2 How to Use this Manual…………………………………..………………………….1
    3. 1.3 Overview of Pennsylvania’s Existing Stormwater Management Program….3

Pennsylvania Stormwater
Best Management Practices

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Manual

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Chapter 1

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Introduction and Purpose

Pennsylvania Stormwater Best Management Practices Manual
Chapter 1

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Chapter 1
Introduction and Purpose
1.1
Purpose of this Manual………………………………………………………………1
1.2
How to Use this Manual…………………………………..………………………….1
1.3
Overview of Pennsylvania’s Existing Stormwater Management Program….3

Pennsylvania Stormwater Best Management Practices Manual
Chapter 1

Pennsylvania Stormwater Best Management Practices Manual
Chapter 1
363-0300-002 / December 30, 2006
Page 1 of 3
1.1 Purpose of this Manual
The purpose of the Pennsylvania Stormwater Best Management Practices (BMP) Manual is to provide
guidance, options and tools that can be used to protect water quality, enhance water availability and
reduce flooding potential through effective stormwater management. This manual presents design
standards and planning concepts for use by local authorities, planners, land developers, engineers,
contractors, and others involved with planning, designing, reviewing, approving, and constructing land
development projects.
This manual describes a stormwater management approach to the land development process that
strives to:
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.
Manual users are strongly encouraged to follow the progression of prevention first and mitigation
second. Throughout the chapters of this manual the concept of an integrated stormwater management
program, based on a broad understanding of the natural land and water systems, is a key and recurring
theme. Such a thorough understanding of the natural systems demands an integrated approach to
stormwater management, so critical to “doing it better, doing it smarter.”
This manual provides guidance on managing all aspects of stormwater: rate, volume, quality, and
groundwater recharge. Controlling the peak rate of flow during extreme rainfall events is important, but
it is not sufficient to protect the quality and integrity of Pennsylvania streams. Reducing the overall
volume of runoff during large and small rainfall events, improving water quality, and maintaining
groundwater recharge for wells and stream flow are all vital elements of protecting and improving the
quality of Pennsylvania’s streams and waterways.
It is important to note that The Pennsylvania Stormwater Best Management Practice Manual has no
independent regulatory authority. The strategies, practices, recommendations and control guidelines
presented in the manual can become binding requirements only through the following means:
1. Ordinances and rules established by local municipalities, or
2. Permits and other authorizations issued by local, state, and federal agencies.
1.2 How to Use this Manual
The following provides a guide to the various chapters of the Manual.
Chapter 1
– Introduction and Purpose
Chapter 2
– Stormwater and the Impacts of Development and Impervious Surfaces
This section provides an overview of the impacts of development on Pennsylvania’s natural
systems and natural resources, including discussions about the effect of increased runoff
volumes, water quality, stream channel erosion, flooding, and lost groundwater recharge and
stream baseflow.

Pennsylvania Stormwater Best Management Practices Manual
Chapter 1
363-0300-002 / December 30, 2006
Page 2 of 3
Chapter 3
– Stormwater Management Principles and Recommended Control Guidelines
This section discusses stormwater management principles to protect water resources and
provides recommended control guidelines for stormwater management. This chapter also
discusses how the recommended guidelines relate to diverse conditions, such as urban areas
rural settings, brownfield sites and karst topography.
Chapter 4
–Integrating Site Design and Stormwater Management
This section discusses the
process
of comprehensive stormwater management, which begins
with better site design and protection of important natural features first, and the use of structural
Best Management Practices to manage stormwater second. An approach to site design and
stormwater management for Pennsylvania is outlined in flowchart and checklist formats.
Chapter 5
– Non-Structural BMPs
This section describes in detail 13 design and development techniques (non-structural BMPs)
that reduce the impact of stormwater. It includes both specific design practices and
recommendations that may be required or encouraged by municipal officials within the context
of zoning and land development ordinances. Use of these “non-structural” BMPs is considered
to be the primary means of stormwater management.
Chapter 6
– Structural BMPs
This section describes in detail 21 specific engineering measures that reduce and mitigate the
impacts of development. The use of the “structural BMPs” is considered the second step in
stormwater design. Chapter 6 includes recommendations (protocols) for the design of
infiltration systems and for soil investigation for infiltration systems.
Chapter 7
– Special Management Areas
This chapter discusses issues and stormwater management implications unique to some
special management areas such as brownfields, highways and roads, karst areas, mined lands,
water supply well areas, surface water supplies, special protection waters, and highly urbanized
areas.
Chapter 8
– Stormwater Calculations and Methodology
This chapter discusses engineering techniques and methods used to perform stormwater
calculations. Improved sources for rainfall estimates (NOAA Atlas 14, 2004) are suggested.
This chapter also provides guidance on developing stormwater calculations based on the
recommended control guidelines in Chapter 3 of the manual. In addition, this chapter includes
optional flowcharts and worksheets to assist stormwater designers and reviewers organize and
conduct their calculations.
Chapter 9
- Case Studies
This chapter presents case studies of projects that have been implemented throughout
Pennsylvania that incorporate innovative techniques and approaches to stormwater
management. This chapter identifies sites in various regions of the state that users of the
manual may visit to observe innovative stormwater management techniques in a range of
development settings.

Pennsylvania Stormwater Best Management Practices Manual
Chapter 1
363-0300-002 / December 30, 2006
Page 3 of 3
Appendix A
– Water Quality
Appendix B
– Pennsylvania Native Plant List
Appendix C
– Protocols for Structural BMPs
Protocol 1 – Site Evaluation and Soil Infiltration Testing
Protocol 2 – Infiltration Systems Design and Construction Guideline
Appendix D
– Storm water Calculations and Methodology – Case Study
Glossary
1.3 Overview of Pennsylvania’s Existing Stormwater Management Program
The Clean Stream Law of 1937 provides the legal foundation for water quality protection and
restoration, and water resources management in Pennsylvania. The Department of Environmental
Protection is primarily responsible for administering the provisions of the act. The Clean Streams Law
has been affected by passage of a series of federal laws, such as the Clean Water Act (CWA) of 1972,
which has also been amended over time. Local government implements specific regulations for land
development and stormwater management. Pennsylvania has 2566 municipalities and 376 designated
stormwater management watersheds, with diverse natural, social, and cultural features. The
Pennsylvania Municipalities Planning Code (MPC) law enables, but does not require, comprehensive
planning, zoning, and subdivision/land development regulation on the municipal, county, and regional
levels. To achieve regulatory status, the recommendations and guidelines in this manual must be
implemented by ordinances and zoning at the municipal level.
The Pennsylvania Storm Water Management Act of 1978 (Act 167) provides the legislative basis for
statewide stormwater management. The Act 167 stormwater management program is mandated,
administered, and funded at a 75 percent level by the state. However, stormwater management plans
must be developed by the respective counties in a given watershed, and be implemented by the
effected municipalities through the adoption of stormwater ordinances. This is a rather uniquely
structured “sharing” of authority and powers by all levels of Pennsylvania government.
In addition to the requirements under local zoning and ordinances, federal regulations require individual
land development projects to obtain National Pollutant Discharge Elimination System (NPDES) permits.
These permits are required for all land development projects that disturb one acre or more. The
permits authorize discharges from erosion and sediment control facilities and approve post-construction
stormwater management plans. The 1999 update to the federal stormwater regulations also required
923 small municipalities and numerous institutions throughout Pennsylvania to obtain NPDES permits
for their stormwater discharges. Each permit holder must implement and enforce a stormwater
management program that reduces the discharge of pollutants to the maximum extent practicable.
More detailed discussions of individual and municipal NPDES construction and stormwater
management permits can be found on the DEP web site under the keyword “Stormwater Management”.

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