We abuse the land because we regard it as a commodity belonging to us'

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We abuse the land because we regard it as a
commodity belonging to us.

• When we see land as a community to which we
  belong, we may begin to use it with love and
  respect.

Aldo Leopold 1886-1948
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MAKING IT HAPPENSUSTAINABLE WATERSHED
MANAGEMENT
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Stewardship Area
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Stewardship Area
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Stewardship Area
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Stewardship Area
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Stewardship Area
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Stewardship Area
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An Overnight Success Story 14 years in the making
Beginning in 1994, GVAs Sustainable Water
Management Program worked with all the 9 member
municipalities of the Federation of Northern
Chester County Communities. These municipalities
have adopted the principles of our program and
its Model Stormwater Ordinance. Starting in 2005,
GVA partnered with Clean Water Action and the
Delaware Riverkeeper. This new partnership began
working with municipalities that are outside of
GVAs adopted 155 square mile stewardship area
and are offering them the 5th generation of our
Model Stormwater Ordinance along with our
Well-Head Protection Ordinance. These ordinances
surpass the minimum standards of both state and
county models.
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SUSTAINABLE WATERSHED MANAGEMENTTOP-DOWN/BOTTOM
-UP PROGRAM LINKING LAND AND WATER MANAGEMENT
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Sustainable Watershed Management
Central PrincipleThe right
amount of development in the right places using
the right stormwater and wastewater and water
conservation practices can achieve rigorous
sustainable water resources standards, if fully
implemented through municipal comprehensive
planning, zoning, and subdivision/land
development regulations.
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Goals-Maintain stream baseflow-Maintain
groundwater table-Protect existing and future
wells-Minimize flooding-Minimize impacts on
natural stream system morphology-Prevent
groundwater contamination-Minimize nonpoint
source pollution in streams, lakes, and
reservoirs-Maintain natural stream temperature
regimes-Maintain aquatic communities and their
habitat, including wetlands
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The Problem
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WATER RESOURCE IMPACTS OF LAND DEVELOPMENT
Water Quantity
Stormwater Reduced infiltration Lowered
water table Reduced stream baseflow Worsened
cumulative peaking, flooding Streambank, stream
morphology Wastewater Ground and
Surface Water Supply Ground and Surface
Water Quality
Stormwater Nonpoint runoff Temperature Wastewat
er Treatment plant discharges Onsite septics
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Natural Hydrologic Cycle
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Impact of Development on Q7-10 Drought Baseflow
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Infiltration
Surface Runoff
Surface Runoff
Surface Runoff
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Impact of Drought on Groundwater Table and Stream
Baseflow
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First Order Streams

• Smallest, permanently flowing stream in
  sub-basin
• 108 first order streams in Northern Chester
  County watersheds (Horton classification)
• Most vulnerable to drought
• Essential for water quality

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The Problem Water Quality Phosphorus Nitrogen
Sediment Hydrocarbons Pathogenic
bacteria Metals/toxics
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Water quality problems
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Land Development Impacts on Stream Morphology

• Channel widening, downcutting, scouring
• Stream bank erosion
• Imbedded stream substrate with benthic impacts
• Loss of pools, riffles

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Dry Channels
Eroded Streambanks
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Bank scouring
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Unstable habitat
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Temperature changes
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Land Development Impacts

• Peak Discharge is higher for small storms
• Bankfull Flow increases in
• Magnitude
• Frequency
• Duration
• More Frequent Bankfull is more important than
  large floods in shaping channel.

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Land Development Impacts on Stream Ecology

• Reduced diversity of aquatic insects
• Reduced diversity of fish
• Decline of amphibians
• Degraded wetlands, riparian zones

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Consumptive Impacts of Stream Discharge
Wastewater Treatment Systems
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Onsite Septic System Water Quality Impacts
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The Solution GVAs Sustainable Watershed
Management Program Targeting
Stormwater Water Use Wastewater
Management
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The SWM Planning ProcessPhase I Planning
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GIS Inventory Files

• Municipal Boundaries
• Hydrologic Units (Gages, First Order Streams)
• Geology
• Soils (by phase)
• Land use (1990 1993)
• Zoning (by municipal classification)
• Vacant Land (Residential Agricultural)
• Woodlands
• Public Lands
• Contours (50)

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The Technical Program Water Quantity
Modeling Water Quality Modeling
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SUSTAINABLE WATERSHED MANAGEMENTWater Balance
Model/Low Flow Maintenance Model Stormwater
Impacts Water Use Impacts Wastewater Impacts
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Low Flow Maintenance Model

• Calculation of Q 7-10
• Calculation of Low Flow Margin Factor (10)
• Translation of Low Flow Margin Factor into
  Development

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Water Model Database Standard Data

• Watershed sub-basins
• Existing land use
• Developable parcels
• Zoning and sub-basin union
• Landscapes plan and sub-basin union

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The Technical Program Water Quantity Standards
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SUSTAINABLE WATERSHED MANAGEMENTDRY YEAR
NITRATE MODEL
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Nitrate
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Run the Models -Existing Conditions -Future
Build-out Under Current Zoning -Alternative
Development Scenarios
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Base View Sub-Basin Theme
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Base View Existing Land Use
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Base View Developable Tax Parcels Overlayed
with Current Zoning
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Result Tables
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Results Automated View and Layout Display
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75 Build-out withoutSWM Model Ordinance
75 Build-out with SWM Model Ordinance
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SUSTAINABLE WATERSHED MANAGEMENTIMPLEMENTATION
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Phase II Implementation
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Sustainable Watershed Management
Implementation Top-Down Through DRBC and
the IRP Bottom-Up Through Municipal Action
Through Projects on the Ground
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IMPLEMENTATION OF SWM Through Municipal
Action
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Sustainable Watershed ManagementCritical
Municipal Actions How Much? Of What? Goes
Where? Comprehensive Plan Zoning
Ordinance In What Ways? Subdivision
Regulations Stormwater Wastewater Water
Supply
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Municipal Ordinance Provisions

• Stormwater Quality, Quantity-Volume, Quantity-P
  eaking
• Riparian Buffer Zones
• Floodplains
• Special Aquifer Protection
• Wetlands
• Steep Slopes
• Vegetation Protection
• Chemical Application/Fertilization
• Soil Disturbance/Grading

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GVA Stormwater Ordinance

• Volume Control
• Peak Rate control
• Water Quality (NPS) control
• Consistent with PA DEP BMP Manual
• Includes other water resource issues

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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
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Municipal Example IMPLEMENTATION OF SWM
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Comp Zoning SLDO Plan
NorthCoventry Adopted Adopted Adopted
CommentsNorth Coventry prepared and adopted a
comprehensive plan which integrates SWM
extensive modeling was undertaken in this process
with significant changes being made to visioning
for the future. Type of development and
densities were modified substantially. The most
difficult task of adopting changes into zoning
have now been completed, with the new zoning
ordinance adopted in December 2002. A first,
Stormwater and related SLDO needs were completed
earlier. Recently, North Coventry adopted our
model Well Head Protection Ordinance
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Regional Resource Protection Plan
Created by Federation of Northern Chester County
Communities With technical assistance from the
Chester County Planning Commission
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A Table of Existing Natural Resource Protection
Standards
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Buffers 100 Beside every good stream is a good
forest
Pennsylvania Campaign for Clean
Water www.pacleanwatercampaign.org
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CONTACT INFORMATION
John Hoekstra Director of Watershed
Advocacy Green Valleys Association (610)
469-2596 jhoekstra_at_greenvalleys.org