Philadelphia, Pennsylvania

Implementing a Multi-Faceted Approach to Stormwater Management

Community Playground at People's Emergency Center (Source: People's Emergency Center)

For more than a century, the City of Philadelphia has been working to protect water resources through environmental planning and natural area set-asides. The greater Philadelphia area is heavily urbanized and older parts of the city are drained by an aging combined sewer infrastructure. The City has faced a number of water quality challenges in the last few decades as they have addressed various requirements of the Clean Water Act.

In 1996, staff at the Philadelphia Water Department (PWD) undertook an effort, led by Howard Neukrug, to evaluate the infrastructure needs associated with controlling 16 billion gallons of combined sewer flows per year. Costs were expected to run into the billions of dollars. PWD questioned whether, after expending the time and money necessary to implement conventional solutions, local waterways and streams would be healthy. The answer was no: they would still have eroded banks, exposed infrastructure, poor aquatic life, impaired fish passage, and poor aquatic habitat.

PWD decided to integrate their stormwater program with other water resource protection and regulatory programs to improve synergy and develop a holistic approach. The idea was to simultaneously address a number of regulations, including combined sewer overflows, a Phase I NPDES stormwater permit, and Clean Drinking Water Act requirements, while preserving and maintaining the health of the watershed. This was the birth of the Office of Watersheds.

The Office started out with five staff (each focusing on a different water quality regulatory program) and an annual budget of $500,000. From 1996 to 2000, the team worked on developing a comprehensive strategy for stormwater management, while still working toward implementing existing regulatory programs and meeting requirements. Within ten years, the Office grew to 29 positions and a $10 million budget. Now PWD can readily address TMDLs, new permit requirements, and new drinking water requirements within a framework of holistic watershed management. The flexibility of the program to address new concerns allows for a truly proactive approach. Their strategy targets the sources of urban runoff and water quality problems rather than just treating the symptoms.

PDW's approach to water management has evolved as the regulatory landscape has evolved. Chris Crockett of the PWD Office of Watersheds credits much of their success to Philadelphia's Commissioners and Deputy Commissioners openness to new, progressive ideas. This high-level support has been an essential part of transforming the Water Department from a quiet utility into a highly visible department that improves parks, fixes streams, and provides recreational access to water resources, in addition to its traditional role of maintaining infrastructure.

Also, in the past three years there have been a number of storms and 100-year flood events that have helped raise awareness with the public and at the political level that something must be done to prevent catastrophic flooding. This has allowed the City to continue moving forward with water-related initiatives with a broad base of support.

Philadelphia is focusing on three main efforts:
  • Implementing regulations through a performance-based stormwater ordinance to create incentives for BMP use,
  • Building BMPs for research and education
  • Initiating a rate reallocation study to migrate to an impervious-area-based formula for the stormwater utility, which has been in place since 1968

Performance-Based Stormwater Ordinance

New state requirements in Philadelphia's NPDES Phase I stormwater permit dictate the need for increased scrutiny of new development and redevelopment plans. This has led to the development of a revised stormwater ordinance that goes beyond traditional stormwater management and encourages a return to pre-development conditions. In an area as highly developed as Philadelphia, the conventional approach did little to mitigate the adverse hydrologic and water quality effects of hundreds of years of urban development. The new ordinance focuses on a performance-based approach, requiring developers to manage the first inch of stormwater on-site. The ordinance does not dictate how to achieve this level of protection, though it does provide guidance on a variety of innovative BMPs that can be used to meet the requirement.

City managers knew that stormwater management was necessary because it was required in the NPDES permit. Other agencies involved in planning and development, however, did not have the resources, particularly staff time and money, to implement required program components right away. PWD formed partnerships with other City departments and put forth the resources needed to set up a new development review process. They worked with a variety of organizations within the City, including the City Planning Commission and the Department of Licenses and Inspections, to set up the process (including the establishment of online applications) and provided resources, such as staff time and money.

At one time PWD was the last to see development plans and provide input on stormwater and water quality concerns. Now, due to their increased involvement in the process, they are among the first to see plans, even before zoning permit review. As a result, PWD can request changes in designs to accommodate water quality goals before the plans are finalized.

PWD also worked with representatives of the building industry to incorporate their needs and concerns and to further streamline the development review process. Even though the industry would have to face more requirements with the new regulations, the City knew that the changes were not so different from what developers face in neighboring suburban communities with greenfield development.

The performance requirement (and the absence of a prescriptive approach) meant that the development community could be creative and use any combination of management practices (including both "green" and conventional), as long as they met the minimum requirements for water quality, CSO abatement, and flood control. The infill aspect of Philadelphia's new development requirements is part of the key to their success. There are so many requirements associated with conversion of green space to developed land that infill development in Philadelphia is actually easier than in surburban areas.

The first three months after the new ordinance and development requirements were implemented were somewhat chaotic. There was pushback from both the development community and the city agencies involved in building projects. Waivers were requested, though none were granted. The City has found that only a small fraction of projects undergoing review under the new requirements have had to resort to in-kind trades to implement BMPs offsite but within the same sewershed.

One year and approximately 500 development plans later, the City has seen a significant change in the regulated community. Now both private and public developers have learned which engineering firms have adapted to the new requirements and can sail through the review process. To aid the engineers and developers in adapting to the new policies, the City does not charge for plan reviews. They brought in on-site contractors, in addition to regular staff, to review and suggest revisions to submissions. Over time, there has been a substantial decrease in resubmissions.

The green development "buzz" has spread through the development community, too. More and more developers have realized that these BMPs offer benefits beyond stormwater control, and they are trying innovative approaches on their own. The new stormwater requirements fit nicely within the trend to build more energy-efficient and sustainable (e.g., LEED-certified) buildings. Recently, a public housing authority chose to install porous pavement because they had heard that it was comparably priced and would allow for a reduction in the size of on-site drainage pipes. Infill developers can use these new regulations to help garner support for a project by highlighting the potential to reduce neighborhood flooding, as the new requirements "turn back the clock" and improve on predevelopment conditions.

Demonstrating the Benefits of BMPs

Watersheds staff also decided that their land-based program needed to be improved to incorporate a more diverse arsenal of BMPs than what the early Phase I regulations dictated. They wanted to experiment with innovative practices, such as green roofs, tree trenches, and porous pavement, to show developers and other City departments that these ideas are practical. Each proposed BMP was initially met with skepticism.

Some people asked how these practices related directly to bonds and whether they benefited rate payers. The staff in the Office of Watersheds were able to identify metrics and show quantitatively how the approaches help maintain streams and support more conventional infrastructure. They compared costs between infrastructure solutions and land-based solutions, which clearly demonstrated cost benefits of the land-based, sustainable practices. Office of Watersheds staff were also able to show that each dollar spent on such green practices resulted in a tangible, obvious improvement. Specifically, staff showed that the stormwater rate reallocation was estimated to alleviate the need for tanks that control 40 million gallons of stormwater, offering a direct financial benefit to the City.

PWD staff emphasized that BMPs are just one tool to address water quality and flooding. They installed demonstration facilities to let people experience the practices directly. Ideas and information were presented as education, not as a required approach. The staff also linked successes in other communities to what was happening locally (as in, "did you know that a leading green roof firm is located right here in Philadelphia?") and a substantial amount of time was devoted to educating managers and peers about these new technologies.

All of these efforts gradually changed the conventional image of an institution that historically has been more comfortable with more engineered solutions. Now city officials come to PWD with green ideas of their own.

One example of an innovative, urban-oriented program is the Pennsylvania Horticultural Society's Neighborhood Transformation Initiative, established to convert areas of vacant land covered with trash and debris into valuable assets to the communities where they are located. By creating attractive spaces, communities are better able to retain existing residents and business and attract new ones. Also, the converted spaces offer stormwater management benefits because the park-like spaces are outfitted with berms and swales that collect and infiltrate rainfall and runoff, and natural vegetation promotes evapotranspiration. PWD is one of the partners in this endeavor, as well as the Pennsylvania Horticultural Society's larger Philadelphia Green Initiative.

Before: Vacant lot at 2300 North 3rd Street before greening (Source for both: Pennsylvania Horticultural Society)After: Vacant lot at 2300 North 3rd Street was regraded to capture stormwater and planted with trees, shrubs, and grass

Watershed-Level Management

The new requirements set forth in the stormwater ordinance are a significant and very recent step forward, but the city has not limited their efforts to controlling stormwater during development. In the 1990s, Office of Watersheds staff began addressing stream and wetland restoration by building stormwater treatment wetlands and actively restoring degraded streams and wetlands to recreate and recolonize habitats. Staff recognized the need to increase baseflow and reduce scour to protect stream geomorphology and habitat. Their goal was to emulate 10 to 20 percent impervious cover using land-based BMPs, even though actual conditions are as high as 50 to 80 percent imperviousness.

PWD understands the value of meeting end-of-pipe TMDL requirements, but they do not consider the job to be complete if the stream or wetland doesn't support the bugs and other creatures that are meant to inhabit it. Their approach to stream restoration focuses on creating new habitat and recolonizing them with aquatic wildlife to bring them back to a healthy status. Another part of the City's watershed management approach is providing opportunities for recreation by improving access to streams and building stormwater treatment wetlands.

Stormwater Utility Improvements

Currently, the utility charges only metered customers, missing such properties as parking lots, which do not consume water, but which contribute to stormwater runoff. The new rate formula will be based on a combination of impervious area and gross area, and credit will be offered for reducing impervious area. Stormwater assistance loans will be offered for nonprofit organizations and churches to implement BMP projects. The City expects that charges to residential customers would remain the same or decrease, whereas charges to commercial customers would increase somewhat, as would be expected based on the relative amounts of impervious surface for the two types of land use. The City provides other financial incentives, as well, such as a new tax credit for green roofs.

Green Roof at the Fencing Academy of Philadelphia (Source: Pennsylvania Department of Environmental Protection)

Over the long term, the City expects that the financial impact of the stormwater fee will encourage more BMP implementation. They hope that businesses and institutions will consider the balance between initial capital costs for installing a BMP with the reduction over the long term in the rate charged for the stormwater utility.

Positive Feedback

PWD has had enormous success over the past decade, and it continues to revise and improve its procedures. For example, new stream restoration projects will be applied to larger segments to improve cost efficiency, and the process for designing and installing stormwater treatment wetlands will be modified to improve the bid process and facilitate start-up and improve operation and maintenance.

PWD's staff enjoy the praise they receive from members of the community on individual projects and from other cities who want to learn from their successes. They are pleased that the development community has embraced the new stormwater regulations and have started to take the initiative in implementing green solutions.

By restoring in-stream habitat, implementing land-based source controls, and maintaining infrastructure, Philadelphia has embraced a multi-faceted approach to stormwater management and watershed protection. The approach is a well-thought-out combination of engineering and green practices. Collaborative partnerships ensure that program efforts are complimentary and well-informed.

Advice to Other Communities

One of the lessons Philadelphia offers to other communities is that there is more than one solution to managing water resources. A combination of land-based BMPs, hardened infrastructure improvements, and restoration can be more effective. Sometimes a unilateral approach is the only one that seems to have political support, but it is well worth the time and effort to educate managers, officials, and other decision-makers about the importance of a holistic approach. PWD spent nearly 5 years researching and educating before doing any major implementation. They did not feel any pressure to jump out ahead of the curve because they realized the importance of discovery from the pilot process and of buy-in at the top. Ten years ago city officials took a risk—even today the commissioners could put an end to the program—so continuing education is essential.

To have success, communities have to demonstrate all the available BMPs and spend three to five years designing, building, monitoring, and testing each one to see how it works. It is not unusual to find out what does not work well, but it's amazing to see where and how BMPs excel. The City has taken what it has learned from pilot research and determined the design and implementation factors necessary to successfully applying BMPs on a city-wide scale.

To achieve success, Philadelphia recommends that communities should focus on turning the intangible benefits associated with green approaches into real numbers and quantified benefits to which people can relate. They should study the impacts of different alternatives on such important metrics as property values, access to recreation, aesthetics, decreased flooding—even improved interaction of utility crews with the community—and spread the word to both decision-makers and citizens.

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