Regional Greenspace Priorities of Southeastern Pennsylvania

The GreenSpace Alliance

The GreenSpace Alliance (the Alliance) was founded in 1992 as a project of the Pennsylvania Environmental Council (PEC). It is a coalition of organizations and concerned individuals that promotes and advocates for the preservation and enhancement of natural, agricultural and recreational open spaces to preserve the quality of life in southeastern Pennsylvania.

The Alliance is guided by a growing board of leading land conservation, smart growth, environmental and civic organizations, including PEC, Brandywine Conservancy, Natural Lands Trust, Montgomery County Lands Trust, Heritage Conservancy, Chester County 2020, Chester County Open Space Preservation Office, the Pennsylvania Horticultural Society and the Philadelphia Chamber of Commerce. The Delaware Valley Regional Planning Commission (DVRPC) participates in an advisory capacity.

The Alliance seeks to promote and implement a regional vision and practical mechanisms for creating an integrated system of open spaces in southeastern Pennsylvania. Simultaneously, the Alliance aims to help show the linkage between revitalizing urban communities and preserving open space in suburban and rural areas.

The Region

For the purposes of this Plan (and the Alliance's work in general), the southeastern Pennsylvania region(SEPA) is defined as Bucks, Chester, Delaware, Montgomery, and Philadelphia Counties. Some facts follow:

The population as of July 2005 was 3,890,181, growing at about 3% per decade but, more significantly, redistributing itself from Philadelphia and the inner-ring suburbs to the middle and more rural parts of the four suburban counties.
The region contains 238 local municipalities.
The total area is 1,409,000 acres. ¹
Developed land as of 2000 totaled 626,000 acres. ²
Undeveloped land as of 2000 totaled 783,000 acres.
As of 2004, approximately 166,000 undeveloped acres were protected (see Map 1: Protected Land), leaving 617,000 acres undeveloped and unprotected. ³

Challenges in the region include the following:

Between 1990 and 2000, land was consumed by development in SEPA at nearly six times the rate of population growth. ⁴
Viability of agriculture is threatened: Acreage in agriculture declined by 28% between 1970 and 2000.
Sprawl contributes to stream pollution due to increased impervious surface areas causing surface runoff, contaminants, and soil erosion.
Development is impinging on scenic and historic landscapes.

Why Set Regional Open Space Priorities?

Sprawl development in southeastern Pennsylvania is severely impacting the region's ecological resources and green spaces. A 2003 report by the Brookings Institution⁵ noted that in the region over the 15 years from 1982 to1997:

131,000 acres of land were converted to urban uses.
Nearly 55,000 acres of prime farmland were lost.
122,300 new households were built.

Recent years have also seen the following:

Migration of employment opportunities to suburban locations.
Extensive highway construction to accommodate increased traffic loads, which in itself consumes open space and facilitates highway-dependent commercial development.
Scattered development leads to fragmentation of large areas of undeveloped land into smaller, less ecologically valuable parcels.
Threats to water supply, both qualitative and quantitative.
A growing demand for outdoor recreational opportunities such as biking, hiking, fishing, and boating.
The decline of older communities, many of which were built in an era when green space was given little thought and therefore today lack the open spaces and trails that are basic infrastructure for attracting and retaining residents and jobs in an information-based economy.
Rapidly escalating costs of acquiring or otherwise protecting open lands and of converting vacant land to new green space in urban communities.

Complicating factors in addressing this situation include:

Division of the southeastern Pennsylvania suburbs into 238 local municipalities, many of which do not yet participate in multi-municipal planning or have open space funding initiatives within their boundaries.
Differences between political boundaries and watershed boundaries, and a lack of consistent approach to managing watersheds.
Limited availability of funds for open space protection and compatible recreational development.
The Commonwealth's governance structure, which gives authority for land use decisions to local municipalities and limits regional and county-level comprehensive planning to an advisory role-and the absence of a requirement that municipal land use ordinances conform to municipal plans.
Lack of consensus on regional open space priorities to guide funding and related decisions. This is needed urgently, before priceless landscapes, historical sites, contiguous ecological areas, and recreational opportunities are lost.

At current growth rates, DVRPC predicts that 250,000 more acres will be taken for development by 2030. However, with planning for smart growth and smart conservation, this figure can be reduced to 109,000 acres-saving 141,000 acres and generating economic, environmental and cultural benefits (DVRPC Destination 2030 estimates).

County and multi-municipal comprehensive plans are addressing the impacts of sprawl and diminishing open space, and they are strategic blueprints for protecting open space at the local level. Still, in local entities where effective comprehensive planning is lacking, the historic tendency is to respond to development pressures in a reactive way that often leads to developments with negative impacts.

In the face of these immediate pressures, challenges and opportunities, funders, both governmental and private, have difficulty choosing among preservation projects and question whether their resources are being expended as effectively as they might be. While county and multi-municipal plans address the impact of sprawl and diminishing open space in a strategic manner, it is also important to think regionally. This Plan puts a particular focus on thinking regionally; i.e., on a multi-county basis, comparing and prioritizing unprotected open space across the region. The Plan also urges development of a consensus on the balance between open space protection and future growth. While the situation is serious, there are opportunities to slow the tide of sprawl in the years just ahead-if the necessary commitments can be obtained.

The Plan

This Plan was developed by the Alliance, with funding from the Pennsylvania Department of Conservation and Natural Resources (DCNR) and the William Penn Foundation. It is a study of the five-county southeastern Pennsylvania region using Geographic Information System (GIS) technology and expert advisory input to determine and display the value of undeveloped lands for agriculture, ecological conservation, and natural resource-based recreation and to recommend priority areas for protection.

The ecological component of the report was developed by the Natural Lands Trust and is based on their "Smart Conservation" model. The Brandywine Conservancy developed the Plan's agricultural component and the Delaware Valley Regional Planning Commission (DVRPC) developed the recreational component. The original Plan was prepared in 2003 by the GreenSpace Alliance and published in January 2004. In the fall of 2005, DVRPC created an updated version of the recreational component, based on work performed for their long-range plan, and it is presented herein. DVRPC also obtained updated versions of NLT's Smart Conservation model and the Brandywine Conservancy's agricultural model, both of which are included in this updated version of this Plan.

Purpose

Establishing regional priorities has become important, as levels of investment necessary to acquire or otherwise protect land have increased dramatically. Setting priorities is intended to:

Present a well-reasoned and strategic approach to land preservation on a regional scale.
Leverage resources and funding among state and local government, private conservation groups, and others.
Help the region identify the most critical resources and protect them before the pressures of urbanization and sprawl become overwhelming.

Protecting open space on a multi-county regional basis has significant benefits that extend beyond the boundaries of the place protected, impacting the entire region. These include:

Protection of the water supply
Provision of flood control
Enhancement of the quality of life and provision of recreational opportunities
Maintenance of wildlife and natural diversity
Preservation of scenic, historic, and rural character of the region's landscape
Encouragement of new and retention of existing high-quality economic enterprises via provision of nearby open space and recreational amenities

The purposes of the Plan are to:

Foster partnerships and dialogue among state, federal and local government, private conservation groups, and other parties to balance economic growth and protection of open space in the region.
Identify and prioritize open space lands for preservation through a GIS-based analysis.
Establish a linked network of protected open space lands that will improve health and quality of life by:
- Conserving large, unfragmented tracts of open land that protect ecological resources and agricultural lands.
- Linking larger open space nodes with linear open space corridors.
- Encouraging the revitalization of previously developed land.
- Increasing and improving recreational opportunities.
Obtain commitment to the Plan and its recommendations in the form of organizational endorsements.

Methodology

With the aid of advisory groups, the Alliance identified three primary uses for open space-agriculture, ecological function, and recreation-and assembled multiple data layers to determine how valuable the region's land is for each use. Each data layer contains a measurable criterion, such as soil quality (for agriculture), land use and land cover (for ecological resources), and proximity to existing parks (for recreation). A full description of all the data layers used to prioritize land for each open space use is provided in the following chapters.

A raster-based technique is used where each data layer is composed of a grid of 30 by 30 meter cells. In all, there are slightly over 6 million cells in the region. Each of the cells in each layer is assigned a numerical score based on the value of resources in that cell. After cell scores for individual layers are determined, all the layers making up each of the three sub-components are weighted and combined. The process for establishing layer values and weights will be described later in each section.

Ultimately, each cell in the region receives a cumulative score for agriculture, ecology, and recreation.⁶ The cumulative numerical scores are then reclassed into "quantile" format. A quantile denotes groups of equal numbers of cells. For example, separating 100 cells into 10 quantiles would result in 10 groups of 10 cells. Separating 100 cells into 5 quantiles would result in 5 groups of 20 cells, and so on.

For agriculture, ecology and recreation, cells are divided into 10 quantiles. All cells in the highest quantile are reassigned a score of 10. Cells in the next highest quantile are reassigned a score of 9, all the way down to the lowest quantile, which is assigned a score of 1. Using this classification technique, the three major components of this report were assembled: the agricultural priorities map, the ecological priorities map, and the recreational priorities map.

Finally, the three components were used to create two composite maps. In the first composite map, high priority values, i.e., values of 8, 9 and 10, from each component map were overlaid onto one another. These lands represent the top agricultural, ecological, and recreational priorities in the region. Taken together, they total 466,300 acres. In the second map, the values from each component were combined and reclassified to produce one set of open space priority values for the region.

Results

The results of the prioritization model were compared to rural areas-large, contiguous, primarily undeveloped landscapes-and urban and suburban areas-lands that are more heavily developed and located within the region's core. These two types of lands were delineated using DVRPC's Rural Conservation Lands layer and the Urban/Suburban Lands layer from Destination 2030, the region's long-range plan.

Protecting Rural Conservation Lands should be a top priority of regional open space preservation efforts. Within the region's Urban/Suburban Lands, open space conservation should focus on stream valleys and their associated riparian habitats. These areas represent most of the few remaining opportunities for protecting a connected network of natural lands within the region's developed core. They are also a tremendous potential recreational asset.

By overlaying development data on Rural Conservation Lands, it is apparent that they are already experiencing the pressures of development. As of 2000, 175,000 acres were identified as developed-some 22% of the total area of 807,000 acres. Of the remaining 632,000 undeveloped acres, approximately 125,000 acres are protected, leaving 507,000 acres undeveloped and unprotected. Of these 507,000 acres, 401,100 or 79 percent are high-resource-value lands. Development in these rural areas is occurring in a fragmented way, with development sites scattered throughout these lands, threatening their contiguity and connectedness.

The balance of the five-county region contains most of its residential, commercial, and industrial uses. Within this 602,000-acre area, 451,000 acres are developed and 41,000 protected, leaving 111,000 acres undeveloped and unprotected. Of these 111,000 acres, 68,700 or 62 percent are high-resource-value lands.

Advisory Process

GreenSpace Alliance relied on expert advice throughout the development of the Plan and database. Some 135 persons gave input in the course of the Plan's development, and an estimated 330 persons viewed and commented on it during 21 presentations in PowerPoint format between June and December of 2003. In addition, the Alliance's Executive Committee received briefings and provided guidance on a monthly basis throughout the development process.

During Fall 2005 and Winter 2006 the Plan was updated by DVRPC. DVRPC created a new recreational open space prioritization model, and obtained updated versions of the agriculture and ecological models from the Brandywine Conservancy and NLT respectively. DVRPC also updated the Plan with the most recently available population and land use data. Finally, DVRPC replaced the Open Space Priority Areas and Suburban/Urban Priority Areas with the Rural Conservation Lands and Urban/Suburban Lands layers from its long-range plan, Destination 2030.

¹ Region-wide acreage figures are rounded to the nearest 1,000 acres throughout the Report.
² 2000 was the last year for which these data were available.
³ DVRPC's protected open space inventory shows that 176,000 acres of land were protected as of 2004. However, 10,000 of these protected acres were "developed" according to DVRPC's 2000 Land Use file. An example of "developed" protected land would include municipally-owned land used for civic purposes, such as a town hall or fire station, or a large parking area within a park.
⁴ DVRPC, Data Bulletin No. 78: 2000 Land Use by Minor Civil Division, March 2004.
⁵ Back to Prosperity: A Competitive Agenda for Renewing Pennsylvania, Philadelphia Area Profile, Brookings Institution, Washington, DC, 2003.
⁶ Only the ecological model prioritized all land (i.e., all six million plus cells) within the region. The agricultural model prioritized all of the region's land with the exception of Philadelphia. The recreation model prioritized a chosen subset of lands particularly valuable for natural resource-based recreation. The methodology for each section is explained in detail in the subcomponent descriptions.