DelDOT builds barrier to protect IR bridge

A project to protect Route 1 near the Indian River Inlet bridge from wind-driven waves may slow down erosion and overwash, but state transportation officials say the highway could still be compromised during a major storm.

A Delaware Department of Transportation contractor is starting work to shore up the beach and provide more protection from storms to the north section of Route 1 leading up to the bridge.

A series of steel girders will be buried from 30 to 50 feet below grade along an 800-foot stretch of Route 1 on the ocean side, said Doug Robb, DelDOT bridge design engineer.

The work is in reaction to what occurred at the bridge during Superstorm Sandy. Storm surge and sand overwashed Route 1 north of the bridge forcing DelDOT officials to close the bridge from Oct. 28 to Nov. 4 as crews removed sand piled several feet high from the roadway.

Robb is quick to point out that the project – estimated to cost more than $1 million – is not the total solution to potential flooding problems in the area. “This is not to prevent flooding but to help maintain the integrity of the roadway. The sheeting work will provide a last level of protection for the road to make sure it's not undermined during an extreme storm in the future,” he said.

Robb explained that during a storm where the dune system would be breached, sand erosion would slowly expose the wall as a bulkhead of sorts and theoretically keep most water from reaching the roadway. “But this is a short term solution,” he said. “We are more reliant on a long-term plan by the Delaware Department of Natural Resources and Environmental Control for beach replenishment as the first level of protection.”

Until that replenishment occurs, the area continues to be vulnerable to storm surge and overwash, Robb said. It's still possible the road could be closed due to flooding under extreme circumstances, he said.

Flooding in the area has happened before; during Hurricane Irene the same section of roadway was closed. Robb said at that point DelDOT officials discussed a project to better protect Route 1. “At the time, we thought we had more time to take the next step. Now we realize we can't wait any longer,” he said. He said beach replenishment north of the bridge did not occur as anticipated.

In order to install the steel wall, asphalt from a road leading to the old bridge must be removed. Robb said the asphalt is being trucked to another site where it will be recycled.

DNREC is in the process of providing data to the U.S. Army Corps of Engineers to be added to the corps' request for supplemental disaster aid funding from Congress, said Tony Pratt, administration of DNREC's shoreline and waterway management section. It's the corps that is responsible for beach restoration work near the inlet.

Pratt said DNREC wants the corps to widen the beach along Route 1 north of the bridge to establish a dune system similar to Rehoboth Beach: a 100-foot wide dune and 200-foot beach. He said then the existing sand bypass system that pumps sand from the south side of the inlet to the sand-starved north side could maintain the beach.