Pennsylvania Stormwater Best Management Practices Manual

1
Pennsylvania Stormwater Best Management Practices
Manual
Presented by the Pennsylvania Department of
Environmental Protection Bureau of Watershed
Protection
In cooperation with
2
Table of Contents

• Section 1 Intro and Purpose
• Section 2 Stormwater PAs Natural Systems
• Section 3 Stormwater Principles, Goals and a
  Management Model
• Section 4 Comprehensive Stormwater Management
• Section 5 Non Structural BMPs
• Section 6 Structural BMPs

3
Table of Contents

• Section 7 Urban Areas
• Section 8 Highways and Roads
• Section 9 Calculations and Methodology
• Section 10 Case Studies
• Appendix A Water Quality
• Appendix B PA Native Plant List
• Appendix D Calculations Case Study
• Appendix E Manufactured Products

4
Chapter 1Introduction Purpose

• To Improve Stormwater Management throughout
  Pennsylvania
• Over 2,550 municipalities 350 designated
  watersheds
• New Development, Re-development, Infill
• Part of PaDEP Stormwater Program

5
Courtesy of PADEP
6
Stormwater Management

• Federal Clean Water Act 1972
• Pennsylvania Clean Streams Law - 1937
• PA Stormwater Management Act 1978 (Act 167)
• NPDES Post-Construction Stormwater Management
  Plans
• Municipal Zoning and Ordinances

7
67 Counties Over 2,550 Municipalities
8
Stormwater Management

• Relationship Land Use and Water
• Integrated Approach
• Manage Stormwater
• Volume
• Water Quality
• Peak Rate
• Groundwater Recharge
• Stream Impacts

9
Chapter 2 Stormwater and Pennsylvanias Natural
Systems

• Hydrologic Cycle
• Pennsylvania Rainfall
• Impacts of Development and Impervious Surfaces
• Water Quality
• Pennsylvania Watersheds, Soils, Geology

10
Average Annual Rainfall in Pennsylvania
11
0.1 - 1
Average Rainfall Distribution Harrisburg
12
PRE-DEVELOPMENT
13
Rainfall to Groundwater to Streams
14
POST DEVELOPMENT
15
Impacts from Impervious Surface

• ADDS 30 to 36 INCHES OF RUNOFF VOLUME PER YEAR

16
(No Transcript)
17
Stormwater Impacts

• Increased Runoff Volume
• Decreased Evapotranspiration and Groundwater
  Recharge
• Compacted Soils
• Increased Frequency of Runoff Events
• Faster Conveyance of Water
• Erosion and Stream Channel Changes
• Decreased Baseflow
• Impacted Aquatic Life
• Pollutants and Temperature Impacts

18
(No Transcript)
19
Groundwater Recharge Maintains Stream Flow
20
(No Transcript)
21
Dry Channels
Eroded Streambanks
22
(No Transcript)
23
(No Transcript)
24
Responses to increasing urban in basin

EPT richness number of mayfly, stonefly,
caddisfly taxa
Pesticide Toxicity Index Sum of pesticide
concentrations detected after weighting each by
its potential toxicity to invertebrates (or
fish). Munn Gilliom 2001
From Riemann, Riva-Murray, Fischer, Murdoch.
Assessing forest fragmentation/ urbanization and
stream ecosystem responses
25
(No Transcript)
26
Common Bulk Density Measurements
Undisturbed Lands Forests Woodlands 1.03g/cc Residential Neighborhoods 1.69 to 1.97g/cc
Golf Courses - Parks Athletic Fields 1.69 to 1.97g/cc CONCRETE 2.2g/cc
David B. Friedman, District Director Ocean
County Soil Conservation District
27
(No Transcript)
28
(No Transcript)
29
Pennsylvania Watersheds, Soils, Geology
30
(No Transcript)
31
(No Transcript)
32
(No Transcript)
33
GEOLOGIC MAP OF PENNSYLVANIA
34
Chapter 3 Stormwater Management Principles and
Goals
35
Stormwater Forum

• Villanova Stormwater Urban Partnership
• Provided Technical Input and Guidance
• Calculations and Methodology

36
Primary Control Guidance
Stormwater Forum

• Match the existing condition runoff hydrograph
  volume the 2 year storm.
• Peak Rates held to existing levels for the 1
  100 year storm.
• Notes existing Condition is defined as those
  that occurred predevelopment, i.e. the current
  land cover (including impervious area). Existing
  nonforested pervious areas are classified as
  meadow or its equivalent.

37
Secondary Control Guidance

• Baseflow
• Infiltrate Runoff from the first 1/2 of
  Rainfall Calculated as 0.5 x Impervious Area
• Water Quality
• Infiltrate or Capture Runoff from the next 1 of
  Rainfall
• Capture is defined as permanent removal from
  runoff volume. Volume Credits will be added to
  promote green practices.
• Channel Protection
• Control the 1 year peak discharge to the
  equivalent flow achieved by 24 hr extended
  detention of 1 year, 24 hour storm.
• Flood Protection
• Peak Rates held to existing levels for the 1
  100 year storm.

38
(No Transcript)
39
Recommended Control Guidelines for Volume
40
Recommended Control Guidelines for Peak Rate and
Extended Detention
41
Recommended Control Guidelines for Water Quality
42
(No Transcript)
43
Chapter 4 Integrating Site Design

• Provide a design process
• Emphasize non-structural BMP value
• Stormwater not an afterthought

44
SITE PLANNING AND DESIGN PROCEDURES
Lot Configuration Clustering
Vegetated Swales, Filter Strips
Background Factors
Minimum Disturbance, Minimum Maintenance
Site Factors Inventory
Recharge Gardens, Berms
Factors Analysis Constraints vs. Opportunities
Infiltration Structures
Impervious Coverage
Water Quality BMPs
SITE ANALYSIS
Disconnect, Distribute, Decentralize
Design Phase 1 PREVENTIVE BMPs
Design Phase 2 MITIGATIVE BMPs
APPLICANT OBJECTIVES
STORMWATER MANAGEMENT PLAN
BUILDING PROGRAM ISSUES
STORMWATER CALCULATIONS
Township Comprehensive Plan
Zoning Guidance
SLDO Guidance
45
Chapter 5 Non-Structural BMPs

• Each Technique presented as a BMP
• Incentives and Values for Non-Structural BMPs
• Emphasis on preventing/reducing stormwater
• Soils
• Vegetation
• Reduced Impervious

46
Section 5 Non-Structural BMP Categories with
Specific Non-Structural BMPs1.0 Protect
Sensitive and Special Value Resources BMP
1.1 Protect sensitive/special value features BMP
1.2 Protect/conserve/enhance utilize riparian
areas BMP 1.3 Protect/utilize natural flow
pathways in overall stormwater planning and
design2.0 Cluster and Concentrate BMP
2.1 Cluster uses at each site Build on the
smallest area possible BMP 2.2 Concentrate uses
areawide through Smart Growth practices3.0
Minimize Disturbance and Minimize
Maintenance BMP 3.1 Minimize total disturbed
area grading BMP 3.2 Minimize soil compaction
in disturbed areas BMP 3.3 Re-vegetate and
re-forest disturbed areas, using native
species4.0 Reduce Impervious Cover BMP
4.1 Reduce street imperviousness BMP 4.2 Reduce
parking imperviousness5.0 Disconnect/Distribute
/Decentralize BMP 5.1 Rooftop disconnection BMP
5.2 Disconnection from storm sewers6.0 Source
Control BMP 6.1 Street Sweeping
47
1.0 Protect Sensitive and Special Value
Resources
SITE ANALYSIS
48
Protect Sensitive and Special Value Resources
BMP 1.1 Protect sensitive/special value
featuresBMP 1.2 Protect/conserve/enhance
utilize riparian areasBMP 1.3 Protect/utilize
natural flow pathways in overall stormwater
planning and design
49
(No Transcript)
50
(No Transcript)
51
2.0 Cluster and ConcentrateBMP 2.1 Cluster
uses at each site build on the smallest area
possibleBMP 2.2 Concentrate uses areawide
through Smart Growth practices
52
(No Transcript)
53
3.0 Minimize Disturbance and Minimize
Maintenance BMP 3.1 Minimize total disturbed
area grading BMP 3.2 Minimize soil
compaction in disturbed areasBMP
3.3 Re-vegetate and re-forest disturbed
areas, using native species
54
Lot Configuration Clustering
Minimum Disturbance, Minimum Maintenance
Impervious Coverage
Disconnect, Distribute, Decentralize
Design Phase 1 PREVENTIVE BMPs
55
(No Transcript)
56
(No Transcript)
57
(No Transcript)
58
Images courtesy of Rolf Sauer and Partners
Lawn to Sustainable Meadows
Lawn to Sustainable Meadows
59
4.0 Reduce Impervious Cover BMP 4.1 Reduce
street imperviousness BMP 4.2 Reduce parking
imperviousness
60
(No Transcript)
61
(No Transcript)
62
(No Transcript)
63
5.0 Disconnect/Distribute/Decentralize BMP
5.1 Rooftop disconnection BMP 5.2 Disconnection
from storm sewers
64
(No Transcript)
65
(No Transcript)
66
(No Transcript)
67
What Have Other States/Cities Done?

• Portland, OR Tree credits, worksheets
• Maryland credit system
• Disconnect Roof Leaders
• Vegetated Swales

68

• Portland Example
• BMPs that receive direct credit
• Deciduous Trees 100 SF
• 6 Trees 600 SF Impervious Area that is managed

69
Pennsylvania Example Stormwater Credits for
Non-Structural BMPs
70
(No Transcript)
71
Chapter 6 Structural BMPs

• Volume/Peak Rate by Infiltration
• Porous Pavement
• Infiltration Basin
• Infiltration Bed
• Infiltration Trench
• Rain Garden/Bioretention
• Dry Well / Seepage Pit
• Constructed Filter
• Vegetated Swale
• Vegetated Filter Strip
• Berm

72
Structural BMPs Contd.

• Volume/Peak Rate
• Vegetated Roof
• Capture and Re-use
• Quality Peak Rate
• Constructed Wetlands
• Wet Pond / Retention Basin
• Dry Extended Detention Basin
• Water Quality Filters

• Restoration
• Riparian Buffer Restoration
• Landscape Restoration / Reforestation
• Soil Amendment
• Other
• Level Spreader
• Special Storage Areas

73
BMP Elements

• One- page Overview
• Description and Pictures
• AutoCAD Details
• Variations
• Applications (examples)
• Design Considerations
• Detailed Stormwater Functions
• Construction Sequence
• Maintenance Issues
• Cost Information
• Specifications
• 10 to 15 pages per BMP

74
Porous Pavement
75
Infiltration Basins
76
Vegetated Infiltration Beds
Distributing Water in Sub-surface Bed
77
Infiltration Trenches and Rain Gardens
Rainwater can support the landscape and soils,
reducing pipes and basins.
78
Dry Well / Seepage Pit
79
Constructed Filter With Infiltration
80
Vegetated Swale
81
Vegetated Filter Strip
82
Infiltration Berms
83
Vegetated Roof
84
Roof Capture / Reuse
85
Constructed Wetlands
86
Wet Pond / Retention Basin
87
Dry Extended Detention Basin
88
Water Quality Filters
89
Riparian Buffer Restoration and Reforestation
90
Landscape Restoration
Seeding
1st year
Lawn to Sustainable Meadows
2nd year
3rd year
Images courtesy of Rolf Sauer and Partners
91
Soil Amendment / Restoration
92
Chapter 7 Stormwater Management for Urban Areas
93
(No Transcript)
94
(No Transcript)
95
Stormwater BMP Challenges in Urban Areas

• High densities of imperviousness (50 to 100).
• High property values, limited physical space, or
  lot-line to lot-line development.
• Compacted soils, contamination.
• Underground utilities gas, steam, sanitary,
  building foundations.
• Severely impacted streams, original streams
  enclosed/buried in culverts.
• Elimination of much of the original floodplain
  through placement of fill and structures.
• .

96
Stormwater BMP Challenges in Urban Areas (cont)

• Direct connection of impervious surfaces  
• Combined sanitary-storm sewers.
• High levels of trash, debris and pet waste.
• Stormwater hot spots industrial areas,
  vehicle service areas, public works storage
  areas, dumpsters, etc.
• Regulations and ordinances that may conflict with
  current BMP design strategies.
• Limited economic resources, and the need to
  encourage not discourage- redevelopment.
• .
• .

97
In Urban Areas Stormwater must be Part of Built
Environment

• Parking Areas
• Sidewalks
• Planting Beds
• Green Conveyance Elements
• Roofs
• Physical Space and Economics

98
(No Transcript)
99
Rain Barrels

• 60-gallon Rain Barrel holds 8 cf
• 2 Rain Barrels 16 cf

100
Infiltration Beneath Walkways
101
Chapter 8 Stormwater Management for Highways and
Roads
102
Highway and Road Stormwater Issues

• High Levels Total Suspended Solids
• High Levels pollutants
• Use of Vegetative, linear BMPs
• Spills
• Deicing
• Temperature
• Physical Space Constraints

103
(No Transcript)
104
(No Transcript)
105
Chapter 9 Stormwater Calculations and
Methodology

• Guidelines for Volume, Peak Rate, and Extended
  Detention Calculations
• Flowcharts
• Worksheets
• Integration of Volume and Peak Rate
• BMPs provide volume and peak rate control

106
(No Transcript)
107
No Weighted CN Use in Volume Calculation
108
(No Transcript)
109
Peak Rate Calculations

• Detailed Routing
• Composite Stage-Storage-Discharge
• Adjusted Tc for BMPs - DURMM

110
Chapter 10 Case Studies

• Built projects around the state
• Locations, information, contacts

111
How we Manage Stormwater on a Site-by-Site Basis
affects entire Watershed
112
WHERE ARE WE HEADED

• Initial Focus Group Meeting
• January 19 Wilkes Barre
• January 21 Williamsport
• January 25 Meadville
• January 26 Greensburg
• January 27 Harrisburg
• January 28 Norristown

113
MISSION

• Review Manual
• Does It Work For You
• Good Points
• Uncertainties
• Clarifications

114
Second Meeting Dates

• February 28 Wilkes Barre
• March 2 Meadville
• March 3 Greensburg
• March 7 Norristown
• March 10 Williamsport
• March 11 - Harrisburg

115
Beyond The Focus Groups

• Comments will be recorded from the second Focus
  Group meeting
• Comments will be taken to the Stormwater
  Management Oversight Committee for discussion
• Manual will be revised
• Public Review and Comment Period
• A Final Manual will prepared and distributed
• Training!!!!!

116
Stormwater Information

• Stormwater information (manual revisions,
  meetings, training, etc.) will be posted on the
  DEP Stormwater page
• www.dep.state.pa.us
• Keyword stormwater
• General information
• Stormwater Oversight Committee

117
(No Transcript)
118
Site Navigation

• Stormwater Oversight Committee    
• Erosion and Sediment Control Manual
• Permit Guidelines for Phased NPDES Stormwater
  Construction Permits
• Comprehensive Stormwater Policy Comment and
  Response(Sept. 28, 2002)(PDF)
• Comprehensive Stormwater Management Policy (Sept.
  28, 2002)(PDF)
• Acceptable BMP's in Pennsylvania for Post
  Construction Stormwater Management    
• Stormwater Videoconference (October 3,2002)
• Stormwater Management Act (53K PDF file)
• Stormwater Management Guidelines and Model
  Ordinances (Final Technical Guidance 392-0300-001
  - PDF file)
• Stormwater Management Program (15K PDF  file)
• Factsheet NPDES Permits for Stormwater
  Discharges Associated with Construction
  Activities (PAG-2)

119
Questions ?