Feb. 22, 2012:  The Bronxville Board of Education, at its regular meeting on February 16, heard the good news that assistance with flood relief might be on the horizon.  Village Administrator Harold Porr reported to the board that the Federal Emergency Management Agency (FEMA) has recommended funding approval for planning and design work on a project designed to mitigate flooding in the Bronxville School area.

With a goal of significantly reducing flood damage, the project analysis began after the April 2007 storm and involved hydrologic studies, flood impact studies, and topographical analyses.  "We looked at four alternatives," said Paul Pelusio of J. Robert Folchetti & Associates, consultant to the village.  "Each one included storing water runoff to reduce the amount of flooding.  Some of the alternatives also included a pumping system."  He stated that pumping on its own would not provide a viable mitigation measure because it would adversely affect communities downstream.  "We have developed an alternative that includes both pumping and storage," he said.

The objective, Pelusio explained, is to have the ability to store excess runoff and maximize the window of time between the beginning of a storm and the peak storm-generated river flow to pump the stored water back into the Bronx River, thereby emptying the tanks to receive more runoff.

Pelusio reported that the Bronxville School campus and surrounding properties, while located in the approximately 417-acre Midland Valley Drainage Basin, are not actually located in the direct flood plain of the Bronx River.  A conveyance system of pipes with check valves runs under the landmass between the school and the river and connects the two.

"We analyzed what would happen under various storm-event conditions," Pelusio said, and found that there is a significant window of time--approximately seven hours--between the time the Bronx River reaches its peak during a hundred-year storm and when the Midland Valley Drainage Basin reaches its runoff peak.  During that seven hours we would be pumping the storm water that has accumulated."

Based on results of studies, engineers found that the existing storm-water conveyance system begins to exceed its capacity between the five- and ten-year storms when between 4.3 and 5 inches of rain fall within a 24-hour period.   "During higher storm events, as we experienced in April 2007, water can actually accumulate at the same elevation on the school campus as it does in the river," Pelusio said.  He explained that the current conveyance system's check valves create problems when storm water runs down into the Midland Valley Drainage System and has nowhere to go.  "It begins to accumulate in the school area," he said.

The proposed storage facility, a system of underground tanks, would most likely be located in the natural turf grass area on the school property between the parking lot and the athletic field.  A small pumping station, whose location can be flexible, will be required to reduce the impact of a hundred-year storm.  During a hundred-year storm, 7.2 inches of rain fall within a 24-hour period.  The village received 7.8 inches in April of 2007 and 5.3 inches during Tropical Storm Irene in September of 2011.

"We began this study before we thought another hundred-year flood would come in three years," Harry Porr said.  "I'm very happy to say that we're close to getting funding for phase I of this project."

Porr described the grant application process begun in December of 2010.  The village submitted its application to FEMA for funding under the Unified Hazard Mitigation Assistance (HMA) Grant Program.  FEMA administers the program in cooperation with the New York State Office of Emergency Management (OEM).  In June of 2011, FEMA completed a technical review and a detailed cost/benefit review of the application and deemed it eligible for funding.  The village submitted updated cost information in December of 2011.  "It's our understanding there has been a final recommendation by FEMA for phase I funding approval," Porr said.  "What's truly exciting is that as much as 75 percent of that funding will be paid for by the federal government."

The total cost approved by FEMA and OEM is $7.2 million and includes phase I planning and design for $626,000; construction for $6.2 million; and construction administration and inspection for $313,000.

"We look at the village and Bronxville School as one," Porr said, "and whatever it takes to make this work, we'll work up those protocols.  If everything works well, it may be an opportunity for us to alleviate the terrible kind of flooding we've experienced."

Pictured here:  Bronxville Board of Education member Denise Tormey with Dr. David Quattrone, superintendent of the Bronxville schools, at the February 16 board meeting.

Photo by Carol P. Bartold