Steep Slope Protection
The rolling hillsides of Chester County offer a significant environmental function of providing wind breaks and stormwater management. Slope management allows a municipality to protect areas of steep and moderate slopes from indiscriminate disturbance. Uncontrolled disturbance of steep slopes and vegetation on slopes can result in:
- Increased stormwater runoff, erosion, sedimentation and siltation of nearby streams;
- increased downstream flooding and siltation; and
- decreased stability of the slope which can lead to slope collapses and increased municipal liability for allowing the development that caused such collapses.
A variety of approaches to steep slope management are available to local governments. Applicable to all of Chester County's landscapes, municipalities with undeveloped slope areas within their boundaries should consider developing slope protection regulations. Such regulations are generally located in both zoning and subdivision and land development ordinances.
Steep slope preservation tools are associated with the following advantages:
- Conserves energy by avoiding unnecessary slope stabilization and construction activities;
- Reduces the possible loss of life and property related to development on steep slopes;
- Reduces erosion, sedimentation of nearby streams, and related downstream flooding; and
- Reduces the chance of slope collapse and associated municipal liability.
Steep slope preservation tools can be associated with the following limitations:
- Increased administrative and enforcement responsibilities;
- Potential for excessive regulations: Some applicants may find regulations that prohibit disturbance to steep slopes to be excessive, because development in areas of steep slope in other parts of the country is sometimes permitted through the use of engineering solutions.
How to Use This Tool
Provisions for slope management are typically included in both the municipal zoning ordinance and the subdivision and land development ordinance. Before such provisions are drafted, a policy basis for slope management should be established in the comprehensive plan and/or open space plan. Ideally, sloped areas within the municipality should be inventoried (with appropriate mapping), but such inventory may not be necessary if zoning and subdivision ordinance definitions are clear. Most municipalities distinguish between "moderate slopes" of 15% or greater and "severe slopes" of greater than 25% slope. The applicant will be required to identify steep slope areas in the site plan and demonstrate how such areas will be protected from disturbance or where disturbed, how such disturbance will be mitigated.
After a policy basis is established, a municipality should amend its zoning ordinance to include steep slope land use and maximum disturbance provisions. The subdivision and land development ordinance should also be amended to ensure that slopes are identified and mapped during the plan review process and that disturbance of slopes during the construction process is managed to minimize erosion and sedimentation.
Most Chester County municipalities currently regulate slopes. The following examples illustrate the approached taken by municipalities:
- East Bradford, London Britain & London Grove Townships have established a Steep Slope Conservation districts, which are an overlay to all other zoning districts.
- Kennett and North Coventry Townships regulate steep slopes in a comprehensive Natural Resource Protection article in their zoning ordinances.
The Pennsylvania Municipalities Planning Code (Act 247) specifically allows for protection of slopes. Section 603(b)(5) indicates that "zoning ordinances may permit, prohibit, regulate, restrict and determine...protection and preservation of natural resources". Section 605(2)(iii) is more specific, stating that zoning ordinances may regulate, restrict, or prohibit "uses and structures at, along, or near...places of relatively steep slope or grade, or other areas of hazardous geological or topographical features."
The Pennsylvania Code, Title 25 Environmental Protection, also addresses steep slope protection.
- Riparian Buffers
- Site Analysis Plan
- Natural Resource Protection Ordinance
- Stormwater Management: Best Management Practices
Steep slope protection supports the Natural Resource Protection policies, specifically the Land, Biotic and Water Resource policies established in Landscapes2. Landscapes2 also recommends that local and multi-municipal plans and ordinances include provisions to reduce the cumulative impacts of development and redevelopment on land and water-based natural resources.
Steep slope protection can help reduce damage from erosion or slope collapse and can reduce the energy expended in clean up activity. Because this tool promotes energy conservation, it is consistent with one of the primary objectives of Landscapes2, as expressed in Objective EC 1: Reducing Demand and Consumption, seeks to "Promote energy conservation that reduces demand by individual consumers, the county, and other public and private entities".