Just like scrunchies, mullets, and record players, what’s old is new again in the City of Philadelphia.
Since 2019, RK&K’s Water/Wastewater team has held an open-end contract with the City of Philadelphia Water Department (PWD) to provide multi-disciplinary services aimed at repairing and rehabbing the City’s aging water and sewer systems.
The team has provided general engineering services for the water main, sewer, and stormwater infrastructure capital replacement program to supplement PWD’s in-house engineering staff and provide expertise when and where needed. As part of this contract, they assisted the PWD towards meeting their goal of replacing 20 miles of water mains and seven miles of sewers annually. As the capital program has evolved, there has been discussion to possibly increase the annual replacement goal to 32 miles of water mains.
“Our work is primarily in public right-of-way and city streets where we provide replacement of existing water mains, including distribution and transmission systems. We provide reconstruction of the existing combined and separate sewer systems,” explained Project Delivery Leader Nikunj (Nik) Karumsi, PE.
Over the past four years, the team has worked on 19 rehab and replacement projects, which Karumsi said were badly needed simply due to age of infrastructure where it’s not uncommon to replace a 100+ year old water/sewer piping. The city will eventually have to replenish and/or rehab its entire water and sewer system, over 3,000 miles within the city limits, at some point, since a utility usually has a 100-year lifespan. This means the city should be replenishing 30 miles of water/sewer every single year to meet that life cycle.
Existing water main conditions include rusting inside of the pipeline, or “tuberculation” which reduces inner pipe diameter causing flow restriction, and degradation of water quality. As part of project prioritization, the city collects this information in addition to customer complaints about dirty or brown water, insufficient water pressure, along with water main breaks. Based on these datasets, the City performs condition assessments in-house and groups a few blocks of water main replacements into a single project, which may be delegated to a consultant for development of design plans and to prepare a bid package.
RK&K is responsible for addressing these issues and providing designs that meet current industry and PWD standards.
“A lot of our work is up-front, it’s the base plan stage where we perform utility investigation services to locate, identify, and label the existing underground utility network. This is the most important part of these projects in an urban area full of utilities because it provides the prospective bidding contractors with a good idea of what is below ground. That information is so crucial to guaranteeing the success of a water and sewer project,” said Karumsi.
On the sewer side, approximately 70% of the City has combined sewer systems, which means a single pipe carries both stormwater and sanitary flow from properties into one flow stream. The remaining portion of the city has separate sewers where flow streams are directed to separate stormwater conduit and a sanitary sewer, typically constructed in a piggy-back arrangement. As part of the City’s condition assessment for the sewer systems, they keep score of various data including damaged service laterals, size restrictions in the network, stormwater ponding on street surfaces, and capacity enhancement requirements due to proposed land development and/or flood modeling. Based on the scoring, they group a few blocks of sewer reconstruction into a project that may or may not include water main replacement. The projects are then delegated to a consultant for development of design plans and to prepare a bid package.
In many instances, if the existing sewer condition is satisfactory and meets the capacity requirements, they may opt to rehabilitate the system with sewer lining instead of open-cut sewer reconstruction. These rehab projects are less intrusive and result in a better quality of life for adjacent property owners during construction.
The projects are typically unit price-based, and our fees are determined using how many linear feet of water and/or sewer are replaced as part of any given project. The team has strategic subcontractors on that provide support services such as topographic surveying, base plan preparation, green stormwater infrastructure design, and more.
Once the base plans are complete and approved, they begin the design stage of the project by laying out the locations of proposed water and/or sewer lines while considering future water and sewer reconstruction.
“The intent isn’t just to put in another pipe, it’s to think through the best ways to set up that pipe for a future extension.”
While most of their work follows the same process and procedures, each project is unique and has its own “quirks”. Some projects may also include incidental services such as Green Stormwater Infrastructure design which is a critical component of the City’s Long Term Control Plan (LTCP) with the Pennsylvania Department of Environmental Protection. These projects are designed to direct surface stormwater flows into underground and surface storage systems which may provide infiltration and/or detain flow for a period of time to free up sewer capacity during rain events. This greatly improves the City’s objectives of reducing combined sewer overflows, one of the key requirements of the LTCP.
Karumsi contributes the success of these task orders to this adaptability and knowing the client and their preferences and standards when it comes to drafting, design, and layout. He spent more than a decade with PWD prior to arriving at RK&K.
The team was recently re-selected for the next contract cycle, meaning they will continue working on the City of Philadelphia’s water and sewer system for at least the next four years.
