Roadway drainage project alleviates highway flooding with duckbill check valves
Route 73 is a major artery connecting numerous southern New Jersey communities to Philadelphia via the Tacony Bridge over the Delaware River. In order to alleviate congestion along this critical artery, the New Jersey Department of Transportation (NJDOT) embarked on a road improvement project to streamline traffic flow along the busy Route 73 corridor by adding lanes and widening shoulders.
One particularly challenging aspect of this project was addressing road drainage issues. Southern New Jersey’s flat terrain is crisscrossed by a lacework of tidal streams, like Pennsauken Creek, which runs parallel to Route 73, with just a few feet of vertical separation between the normal water level and roadway.
For decades, motorists accepted periodic road flooding as inevitable during rain squalls and high tide periods. Civil engineers were caught in a vicious cycle: Installing ever bigger drainage pipe helped remove water from the highway during the initial part of a rainstorm, but after a time lag, streams and creeks become rain-swollen, especially during a high tide, when the Delaware River flows back into the feeder streams and tributaries. Water would reverse direction, flowing backward through the large pipe, gushing from storm drains and flooding roadways to the point where they become virtually impassable. Homeowners and business adjacent to the right-of-way complained repeatedly to NJDOT officials about property damage caused by flooding attributed to improper drainage from the highway.
NJDOT realized that widening access ramps and bridges was counterproductive if road flooding brought traffic to a halt during a high tide or severe rain event, so it needed a better solution.
The solution was to install Onyx duckbill check valves at drainpipe outlets. The valves are specifically designed to discharge lartge volumes of rainwater with virtually negligible head loss, and then reliably close to prevent reverse flow during high water events. They will not corrode, jam, freeze or clog on debris. They operate silently, are unaffected by road trash such as plastic bottles, and are immune to damage caused by dirt and oil runoff from road surfaces.
Since completing the highway and drainage improvements in 2010, including the duckbill check valves, NJDOT reports that traffic along the Route 73 corridor traffic has flowed unimpeded and complaints from private property owners adjacent to the highway right-of-way about flooding have ceased.