1.1 Applicability Factors

This Section contains guidance on the project characteristics that determine which portions of the Philadelphia Water Department (PWD) Stormwater Regulations (Stormwater Regulations) apply to an applicant’s project. PWD requires submissions for all projects in the City of Philadelphia that generate earth disturbance of 5,000 square feet or more, yet not all projects will need to comply with all requirements of the Stormwater Regulations. There are three main factors that determine which requirements of the Stormwater Regulations apply to a project:

• Development Type (Section 1.1.1),
• Watershed (Section 1.1.2), and
• Earth Disturbance (Section 1.1.3).

These three project characteristics play an important role in determining how the Stormwater Regulations discussed in Section 1.2 are applied to a project. The applicant will use this Section to identify the project’s development type, watershed, and earth disturbance area. This information, in conjunction with the requirement-specific exemptions in Section 1.2 and clarifications provided for Stormwater Retrofits in Section 1.3, is necessary for determining applicability and the project’s Review Path in Chapter 2.

Of the three key applicability factors, one – earth disturbance – can change during the course of design and construction. If the earth disturbance threshold changes, the applicant must return to Section 1.1.3 to verify whether the project’s applicability determinations have changed.

1.1.1 Development Type

Development type plays a key role in determining if and how Post‑Construction Stormwater Management (PCSM) Requirements (Section 1.2.1) will apply to a project.

Development is defined in the Stormwater Regulations as any human-induced change to a tract of land, whether public or private. Development encompasses, but is not limited to, New Development, Redevelopment, Demolition, and Stormwater Retrofit. It includes the entire Development Site, even when the project is performed in phases. The development types listed below are types that PWD recognizes, and the applicant can only select one development type when completing the ERSA Application (Section 2.1).

New Development

New Development is defined in the Stormwater Regulations as a Development project on a tract of land where structures or impervious surfaces never existed or were removed before January 1, 1970. The improved tract of land refers to the area of on-site earth disturbance.

Redevelopment

Redevelopment is defined in the Stormwater Regulations as Development on a tract of land that includes, but is not limited to, the demolition or removal of existing structures or impervious surfaces and replacement with new impervious surfaces. This includes replacement of impervious surfaces that have been removed on or after January 1, 1970. The improved tract of land refers to the area of on-site earth disturbance.

Demolition

Demolition is defined in the Stormwater Regulations as a project that is limited to the razing, or destruction, whether entirely or in significant part, of a building, structure, site, or object; including the removal of a building, structure, site, or object from its site or the removal or destruction of the façade or surface.

Phased Projects with Demolition then Subsequent Development and/or Retrofit Construction

Many development or retrofit projects begin with a demolition/site clearing phase. In most circumstances, the review of the demolition can occur within the review of the development/retrofit. In these circumstances, the applicant would select “New Development,” “Redevelopment”, or “Stormwater Retrofit” on their ERSA Application and follow the appropriate Development Compliance or Stormwater Retrofit Review Path. If the demolition must occur prior to completion of the review, then the applicant will need to submit a separate ERSA Application using the “Demolition” development type and follow the Demolition Review Path.

Redevelopment of an Earlier Development or Retrofit Project

Property is constantly being redeveloped in Philadelphia, whether the result of new ownership or when an existing owner wishes to make improvements to their own site. Before undertaking a development or retrofit project, it is important to determine whether the land where the improvement is proposed was previously subject to Stormwater Regulations or managed stormwater through a voluntarily installed SMP. Most properties that fall into this category will have an Operations and Maintenance (O&M) Agreement recorded against the deed (Section 6.1) and are also identified on the Green Stormwater Infrastructure Projects Map. If the land was previously subject to Stormwater Regulations or has an existing SMP on-site, the applicant must contact PWD prior to submitting their ERSA Application. This can have a significant impact on the project’s Review Path and whether a new ERSA Application is required or if the improvement should be submitted as a PCSMP Field Change under an existing project tracking number.

1.1.2 Watershed

The watershed in which a project site is located plays an important role in determining how PCSM Requirements (Section 1.2.1) are applied to a project. For example, ongoing watershed-wide Pennsylvania Stormwater Management Act (Act 167) planning studies determine Flood Management Districts for controlling peak rates of runoff; watershed locations are also used to determine the applicability of the Channel Protection requirement for Redevelopment projects. For this reason, it is important that the applicant identify the correct watershed early in the design process. Watershed Maps in Appendix D provide a basic guide, but the applicant can also contact PWD to verify a site’s watershed location.

There are seven major watersheds in Philadelphia:

• Darby and Cobbs Creeks,
• Delaware Direct,
• Lower Schuylkill River,
• Pennypack Creek,
• Poquessing Creek,
• Tookany/Tacony-Frankford, and
• Wissahickon Creek.

Watershed-based regulations are evolving to address stormwater challenges within Philadelphia. While the Stormwater Regulations apply to all New Development and Redevelopment projects that result in earth disturbance totals of 15,000 square feet or more (Section 1.1.3), watershed-specific regulations trigger the Stormwater Regulations at a lower disturbance threshold. Project sites located in the Darby and Cobbs Creeks Watershed and in the Wissahickon Creek Watershed are subject to additional watershed-specific stormwater management requirements. The latest information about watershed-specific regulations can be found on the PWD Stormwater Plan Review website.

Darby and Cobbs Creeks Watershed

Projects located in the Darby and Cobbs Creeks Watershed are subject to the provisions of the Darby and Cobbs Creeks Watershed Act 167 Stormwater Management Plan. Because the Stormwater Regulations were developed to comply with the plan for the Darby and Cobbs Creeks Watershed, all projects that propose 5,000 square feet or more of earth disturbance in the Darby and Cobbs Creeks Watershed are subject to the Stormwater Regulations and their associated PCSM Requirements (Section 1.2.1).

1.1.3 Earth Disturbance

Earth disturbance is the primary factor that determines whether a project is subject to the Stormwater Regulations. It is also a primary factor in determining the applicability of PCSM Requirements (Section 1.2.1) and the E&S requirement (Section 1.2.2). As such, applicants must properly and accurately assess the limits of earth disturbance associated with development projects to determine applicable requirements and the Review Path required.

While earth disturbance of 15,000 square feet or more triggers the PCSM Requirements for New Development or Redevelopment projects in most areas of the City, earth disturbance of 5,000 square feet or more triggers the PCSM Requirements for these project types in the Darby and Cobbs Creek Watershed. Some projects located in the Wissahickon Creek Watershed may also be required to comply with PCSM Requirements at even lower earth disturbance totals. The applicant is referred to Section 1.1.2 above for specific requirements regarding projects located within the Wissahickon Creek Watershed or the Darby and Cobbs Creeks Watershed.

Earth disturbance is defined in the Stormwater Regulations as any construction or other activity that disturbs the surface of land. Examples of activities that consist of, or can commonly involve, earth disturbance include, but are not limited to, the following:

• Excavation;
• Embankments;
• Land development;
• Subdivision development;
• Moving, depositing, stockpiling, or storing of soil, rock, or earth materials, except as excluded below;
• Demolition activity that results in the disturbance of the land beneath or surrounding a structure, including foundation or building slab removal;
• Concrete slab removal;
• Development above subsurface structures where earth, such as gravel or dirt, is exposed;
• Stormwater Retrofits that include ground-level SMP installation;
• Utility connections, including work in the public rights-of-way;
• Installation of new Streets;
• Street Maintenance Activities;
• New paving and full depth pavement replacement;
• Installation of E&S controls and construction-related disturbance located over existing pervious areas, such as establishment of rock construction entrances, stockpiles, silt fencing, construction vehicle paths, staging, and fill areas;
• Grading;
• Clearing and grubbing; and
• Landscaping.

Activities that are not typically classified as earth disturbance include the following:

• Interior building renovations;
• Temporary stockpiles or rock construction entrances located over existing impervious surfaces;
• Restriping of paved areas; and
• Milling and repaving of existing paved areas, as long as the pavement subbase is not exposed during the milling process. The pavement subbase is defined as the layer of aggregate material laid on the subgrade, on which the base course layer is laid.

Some earth disturbance activities and their associated areas count toward the regulatory disturbance threshold for triggering PCSM Requirements, but are not required to be managed in the post-development condition. Such activities include the following:​

• Demolition, provided the surface of the land is returned to a pervious condition;
• Waterway encroachment activities occurring within streambanks, rivers, or other waterways for the purpose of repairing the waterway. This can include streambank stabilization, dam removal, bridge abutment repairs, dredging, stream restoration, and erosion stabilization activities;
• Artificial turf areas specifically reserved for dog use;
• Certain water features, as determined by PWD, such as spraygrounds, swimming pools, and fountains that will be chlorinated; and
• Earth disturbance located beneath an undisturbed existing impervious superstructure, such as a highway overpass.

There are other earth disturbance areas that do not count toward the regulatory disturbance threshold for triggering PCSM Requirements and are not required to be managed in the post-development condition. When calculating the total limit of earth disturbance for a development project, the earth disturbance area associated with the following activities should not be counted toward the total disturbance value triggering the PCSM Requirements. These areas include:

• Street Maintenance Activities within an existing Street that do not result in increased impervious areas. Examples include sidewalk replacement, asphalt repaving, utility trenching, curb cuts, street tree planting, and installation of associated street features such as ADA ramps, light poles, signs, benches, decorative planters, and Green Stormwater Infrastructure (GSI);
• New sidewalk installation along an existing paved Street; and
• Area disturbed for Stormwater Retrofit installation (Section 1.3).

Applicants who wish to claim exemption from PCSM Requirements as a result of these earth disturbance areas should delineate them separately on E&S Plans submitted to PWD as part of the Conceptual Review Phase.

Earth disturbance activities that are exempt from PCSM Requirements are still required to comply with all appropriate E&S submission and review requirements, which may include PWD approval of an E&S Plan. Submission of an ERSA application is required for all projects that propose more than 5,000 square feet of earth disturbance. The applicant is referred to Chapter 2 for more information on submission requirements. Exemption of a project from PWD’s PCSM Requirements does not necessarily imply that the project is also exempt from PCSM Requirements from other City and State agencies. The applicant is referred to Section 2.6 and Section 2.7 for more information.

Phased Projects, Common Plans of Development, and Contiguous Areas of Earth Disturbance

It is not uncommon for large real estate projects to be developed and permitted in phases. When phasing is proposed, PWD will look at the earth disturbance associated with the entire Development Site to determine applicable requirements under the Stormwater Regulations. The Development Site is defined in the Stormwater Regulations as the land area where any Development activities are planned, conducted, or maintained, regardless of individual parcel ownership. It includes contiguous areas of disturbance across Streets and other rights of way, or private streets and alleys, during any stage of or on any portion of a larger common plan of development or sale.

A project may be considered a “common plan of development” if it is associated with any announcement or piece of documentation (including a sign, public notice, hearing, sales pitch, advertisement, website, drawing, zoning request, etc.) or physical demarcation (including boundary signs, lot stakes, surveyor marking, etc.) indicating construction activities may occur on a specific plot. As an example, a redevelopment of a former industrial site that lays out streets, public parks, schools, areas of commercial development, and residential lots that may be sold to another developer are all considered part of the same development site.

Disturbance along multiple parcels separated by an existing street will not be considered contiguous in cases where the linking disturbance activity is limited to sidewalk replacement and/or improvements to PWD infrastructure such a Private Cost water or sewer extension or GSI installation.