AUGUST 31, 2023 - the U.S. Army Corps of Engineers has announced the release of a draft report for the Eastwick Flood Risk Management Study. The draft report outlines a ‘Tentatively Selected Plan,’ which includes an approximately 1400-foot levee along the left bank of Cobbs Creek within the Eastwick Regional Park and Clearview Landfill. The levee plan is designed to reduce the risk of flood damages to homes, property, and public infrastructure. The Draft Integrated Feasibility Report and Environmental Assessment details extensive engineering, economic, and environmental analyses conducted to date as part of the study.The public is invited to comment on the report by November 1, 2023. Comments can be submitted by mail or by email. It’s important to note that the levee outlined in the Tentatively Selected Plan would require consensus/support from a non-federal sponsor, real estate easements, and multiple years of design for potential implementation.
The U.S. Army Corps of Engineers and the Office of Sustainability, along with other partners, will be hosting an Open House on Wednesday, Oct. 4 from 5-7 p.m. at the Eastwick Recreation Center. The Open House will be an opportunity to learn more about the study and ask questions with USACE representatives and partners. There will also be information about other types of flood resilience measures, including home retrofits, short-term flood barriers, and an alert and early warning system.
The Eastwick study area is in southwest Philadelphia along the confluence of Darby and Cobbs Creeks, west of the Schuylkill River, and north of the Delaware River and Philadelphia International Airport. Eastwick is primarily composed of residential and commercial establishments while the adjacent area to the south and east is explicitly comprised of industrial and commercial establishments. Eastwick has experienced increases in the frequency, duration, and intensity of riverine and marsh flooding during storm events including hurricanes and major nor'easters.
The authority for this project is Section 205 of the Flood Control Act of 1948 (Public Law 80-858), as amended. Under this authority, the U.S. Army Corps of Engineers is authorized to plan, design, and construct small flood risk management projects. Each project is limited to a Federal cost of not more than $10 million, including all project related costs for feasibility studies, planning, engineering, design, and construction. The feasibility study will evaluate an array of alternatives to reduce flood risk in the area.
A U.S. Army Corps of Engineers feasibility study involves assessing problems and opportunities related to water resources issues, coming up with alternative solutions to address those problems, comparing those solutions and, ultimately developing a recommendation. Some studies result in a "no federal action" recommendation. Others result in a recommendation for implementation.
Throughout the study, the team conducts environmental, economic, and engineering analyses to compare alternatives. The Army Corps compares the cost to implement specific alternatives with the benefits (in the case of flood risk management, this means reduced flood damages) if the alternative is implemented. Additionally, the team evaluates if the alternatives are technically feasible from an engineering, environmental, and social standpoint. The final product, a feasibility study report, presents science-based decisions and the reasons that led to those decisions.
The U.S. Army Corps of Engineers signed a Feasibility Cost Sharing Agreement with the Philadelphia Water Department in May of 2019. Study work conducted includes documenting existing conditions and flooding-related problems, analyzing, modeling, and comparing various flood risk management measures. Economic, engineering, and environmental analyses have been ongoing. Several measures were ruled out earlier in the study including structure elevation, acquisition, and floodwalls.
A draft report (to be released in late August 2023) will outline a recommended plan for a levee in the Eastwick Park area near Saturn Place. It's important to note that a recommended plan in a feasibility study remains an option and would not necessarily move forward. It would ultimately be up to the non-federal sponsor (City of Philadelphia) if this option were to move forward for design and ultimate implementation.
USACE team members continue to conduct engineering analyses, with a focus on analyzing the potential for increasing water elevations outside of the study area and studying any complementary measures that may be necessary to mitigate those impacts.
Several related efforts conducted by the Philadelphia Water Department and USACE have informed and led to the current ongoing study:
- Based on historical floods and in direct response to flooding caused by Tropical Storm Lee on September 7, 2011, Philadelphia Water Department (PWD) sent a questionnaire to Eastwick residents requesting information such as source and depth of flooding. This survey was also made available to the public. Based on the responses, PWD developed a geospatial shapefile with attribute data about the properties affected from September 1999 to September 2011.
- In December 2014, USACE completed the Eastwick Stream Modeling and Technical Evaluation report. The study was conducted under the USACE Planning Assistance to States program. The purpose of the study was to preliminarily evaluate whether a levee would provide flood risk management for the Eastwick neighborhood during extreme rainfall events without adversely impacting other properties and residents along Darby and Cobbs Creeks. This study was preliminary in nature and involved various assumptions. The final report recommended to City of Philadelphia that additional study may be warranted.
- In September 2016, USACE completed the Darby and Cobbs Watersheds Hydrologic Study. The purpose of the investigation was to determine more accurate flow-frequency relationships in the lower Darby-Cobbs watershed in the vicinity of southwest Philadelphia, PA. Recent studies, including the Eastwick Stream Modeling and Technical Evaluation described above, had revealed that the hydrologic information for the area was outdated, stream gage information may be inaccurate, and supporting data was lacking. The study reviewed existing flow-frequency estimates in the watershed, investigated discrepancies between the existing estimates, and suggested other methods to provide the best estimates for use in related studies.
A levee is an earthen (soil) embankment built to keep water from a creek or river from flowing out of its bank and flooding a given area. It does not eliminate flooding from all sources.