OCEAN CITY NORTH END STORMWATER PUMP STATION
LOCATION: OCEAN CITY, NJ
CLIENT: CITY OF OCEAN CITY
MARKET SECTOR: PUBLIC
In November 2009, a Northeaster named Nor’Ida caused rainwater flooding and tidal water surging in the summer vacation spot of Ocean City, New Jersey, damaging homes and businesses. In 2014, FEMA Hazard Mitigation Grant Program (HMGP) funds became available to help prevent rain-induced flooding in the North End section of Ocean City.
PS&S staff evaluated the City’s North End 273-acre drainage basin for a 10- year storm event. Enormous rainstorm-generated flows of stormwater were calculated, requiring deeper and larger drainage pipes, and thus demanding a large pumping solution. In addition to the larger, steeper-sloped drainage pipes, with the FEMA HMGP funding, water quality measures needed to be utilized for floatable and sediment removal during 2-year or less storm event flows.
THE PS&S SOLUTION
A 166,000 -gallon-per-minute (gpm) below-grade stormwater pump station was designed to handle a 10-year storm event. The station itself consists of six 280 horsepower mixed-flow, high-volume, low-head “can-type” submersible pumps, each capable of pumping 33,200 gpm apiece. All six pumps alternate in a programmed alternating sequence; however, only five pumps are needed to handle the design flow. For water tightness, all electrical equipment was designed in an elevated building two feet above the 100- year storm base flood elevation (BFE). This new building was blended in with an existing recreation building owned by the City. Specific to water quality, manufactured treatment devices (MTDs) were designed in the upper reaches of the North End drainage basin in order to intercept storm waters and remove upwards to 50% of suspended solids. A 1,750 kW emergency generator was designed to supply around-the-clock power availability in the new electrical building. Lastly, six existing outfall pipes were eliminated and collapsed to a single outfall location which receives the discharge waters from the pump station.