Tookany Creek Flood Reduction Feasibility Study

Begun in 2012, the feasibility study analyzed possible flood-mitigation projects throughout the entire Tookany Creek Watershed.  The original draft plan favored constructing nine dry detention basins functioning as a system – six in Cheltenham Township and three in Abington Township – as the most cost-effective option to reduce flood damage in Cheltenham.  The estimated cost to construct all nine basins was approximately $9.2 million.  After reviewing input from significant public comment, the ACOE revised the plan to feature just six basins, all in Cheltenham Township, at a projected cost of $6.7 million.  The ACOE would cover 65% and the township would pay the remaining 35%.

U.S. Army Corps of Engineers Tookany Creek Flood Damage Reduction Feasibility Study


2015 Tookany Creek Flood Damage Reduction Feasibility Study Updates
Begun in 2012, the United States Army Corps of Engineers (ACOE)'s Tookany Creek Flood Reduction Feasibility Study has analyzed possible flood-mitigation projects throughout the Tookany Creek Watershed.  Preliminary analysis favored constructing nine dry detention basins – six in Cheltenham Township and three in Abington Township – as the most cost-effective option to reduce flood damage in Cheltenham. This is referred to as the "Nine Basin Plan."

The U.S. Army Corps of Engineers (ACOE) has nearly completed the Tookany Creek Flood Damage Reduction Study begun in 2012. Its preliminary analysis favors nine dry detention basins – six in Cheltenham Township and three in Abington Township – as the most cost-effective option to reduce flood damage in Cheltenham.

The study analyzed five alternatives, some with multiple configurations, as well as no action at all, and the ACOE calculated the cost-benefit ratio for each. Although the nine-basin plan was the costliest at about $6,481,000, it also netted the highest annual benefit to the Township.

Dry detention basins are low-lying, open-space areas that would hold back the peak flow of rushing rain water during heavy storm events. They would slow the release of stormwater into streams to minimize downstream flooding. The basins would require minimal excavation and construction to store excess stormwater. That not only reduces costs but also helps minimize environmental impacts.

Instead of large-scale excavation, an earthen embankment would be constructed on the downstream end of the detention basin to capture and control water flows. The embankment would include interlocked gabion baskets and earthen material that would allow flows at non-damaging levels to pass. If the stormwater inflow rate increases above that level, water flowing through the gabion basket structure would be “choked,” so a pool would form in the basin behind the embankment. If the ponding water exceeded the basin’s storage capacity, the embankment could be safely overtopped without failing. After the downstream levels normalize, the water in the basin would be slowly released through the gabion-basket conduit and everything would return back to normal.

The proposed basin locations, which are subject to revision during a detailed design phase, are:

• Doe Lane
• West Waverly Road
• Church Road (Arcadia University)
• Limekiln Pike
• Grove Park
• Highland West (Abington)
• Highland East (Abington)
• Baeder Road (Abington)
• Washington Lane (lower level of Curtis Arboretum).
  

• May 2015
• November 2015 

2013 Tookany Creek Flood Damage Reduction Feasibility Study Updates

The Tookany Creek Flood Damage Reduction Feasibility Study conducted by the U.S. Army Corps of Engineers (USACE) was authorized by the Board of Commissioners in April 2012. The two-phase study encompasses the entire Tookany Creek Watershed because flows from Abington, Jenkintown, Rockledge and Springfield in Montgomery County contribute to portions of flooding issues in Cheltenham.  The study achieved some major milestones in 2013.

At a January 2013 public meeting, USACE presented a hydrologic and hydraulic model that accurately represents existing conditions within the study area. The model was created and validated by extensive research into past rainfall events, stormwater management systems and water runoff patterns, including surveys from recent flood victims. It represents a vital achievement because it enables USACE to predict the impact potential solutions would have in areas affected by flooding, a crucial tool for evaluating options.

Formulating those flood mitigation options is the next phase of the study. That process began in February when Township Commissioners, officials and residents along with experts from numerous federal, state and local agencies joined the USACE in a workshop at Glenside Hall. The participants combined their expertise to brainstorm all reasonable solutions to address the complex flooding issue. The USACE team has provided a report on the plan formulation results.

Options could include structural measures like raising or building levees and floodwalls, bridge modifications, bio-swales and bio-retention basins. Non-structural solutions might entail property acquisitions and floodplain land-use controls. Because many factors contribute to flooding, multiple approaches in combination may be needed to effectively combat it. A detailed screening of alternative plans is anticipated for this July.          

Federal funds are covering approximately $472,500 for the study. The Township’s contributions will total approximately $330,000 in funds and in-kind contributions, such as Township Staff support for the study. Federal funding is also available for the design and construction of structural remedies that could be implemented as a result of the study, which is scheduled for completion in mid 2014.

The study agreement and project management plan are available online.