- Associated Press - Sunday, December 20, 2015

CAPE MAY, N.J. (AP) - Cape May has found an engineering solution to make its replenished beaches safer, but it won’t come cheap.

An innovative study by the city’s engineering firm, Hatch Mott MacDonald, considered one of the first of its kind in the nation, came up with a number of potential solutions to combat a series of injuries since beach replenishment began in 1990. The firm looked into the grain size of the sand, the length and elevation of the rock groins and the slope of the beach.

The engineers recommend mechanically changing the slope of the beach, but it would cost about $1 million and may only last for one beach season, if that.

“There is no assurance on the length of duration of any improvement or change to the slope of the beach,” Mayor Ed Mahaney told The Press of Atlantic City (http://bit.ly/1OgKL1q ).

Robert Gates, of Wilmington, Delaware, who was fishing on the Second Avenue Beach on Friday morning, said he won’t go more than knee-deep into the water when he’s fishing because it can be so dangerous.

“You don’t want to wade too far into the surf because it’s at a steep angle,” he said. “The wash will drag you back in there.”

Trenton Avenue resident Dennis DeSatnick, whose son Chad suffered a severe spinal cord injury on Poverty Beach, urged City Council to continue studying the issue. DeSatnick said there have been more than 500 injuries on the beaches since 2005.

“I worked at Howard Street (beach) in the 1970s, and there was a gentle slope from the seawall to as far as you could go out in the ocean,” DeSatnick said.

Mahaney said most of the injuries have been minor, though a few have been severe, and there is no evidence spinal injuries have risen. Due to medical privacy laws, the city does not have good data. Once the injured are taken to the hospital, the city does not get a follow-up report. He said the city is trying to document the number of injuries through reports from the local Beach Patrol, Fire Department and police.

The beaches now generally drop vertically one foot every 10 feet out into the ocean. The engineers are recommending a drop of one every 25 feet.

Engineer Doug Gaffney said four types of ocean waves come ashore, and a more gradually sloping beach would eliminate the most dangerous one, a “plunging wave” that curls and breaks with a lot of energy, while ensuring mostly a “spilling wave” that merely pushes water ashore like a quickly rising tide.

“A one in 21 slope is the difference between a plunging and spilling wave,” Gaffney said.

But doing this on some of the city’s most popular beaches, from Grant Street to Queen Street along 3,700 linear feet of beach, would cost $850,000. Expanding the project another block in either direction would bring the cost to more than $1 million.

Gaffney recommended doing the work in the spring, as beaches tend to grow in the summer. The winter is when they erode.

The engineer said modifications may even be required during the summer. The good news is slope changes would provide extra sand to use in building up dunes.

Mahaney said both the U.S. Army Corps of Engineers and the state Department of Environmental Protection have told him the city is the first to conduct a detailed study on the issue. The city was the first town on the Jersey Shore to receive federal beach-replenishment funds and the first to register more beach injuries, but Mahaney said it is a landmark study because other towns with beach-replenishment programs are starting to notice similar problems.

The city reacted in recent years with a public-education campaign including brochures, warning signs on the strand and programs in the schools. Mahaney said another public-education push is planned before next summer.

“We’re on the forefront of this,” Mahaney said.

Residents have argued for several years that beach replenishment has increased the drop-off of the beaches. The engineers found no evidence beach replenishment was at fault, but they did present some profiles showing dramatic differences over the years. In 1986, the beach at Baltimore Avenue dropped off one foot every 40.7 feet. Today it drops one foot every 7.6 feet. This changed the waves from spilling to plunging.

Another chart showed a much steeper profile on the Howard Street Beach since 1987. A 1983 design for the beaches called for a vertical drop of one foot every 25 horizontal feet, but the current template is one foot every 10 feet.

There could be ramifications in changing the template since the beaches were designed to protect property from flooding and not for recreation.

“If you change the Army Corps template, you reduce the ability to protect property,” Gaffney said.

Courser sand from replenishment has been blamed for more erosion and the formation of cliffs. The engineers found historic data on sand-grain size. In 1954, it ranged from .13 to .35 millimeters. In 1983, the range was .13 to .18 millimeters. Today it is .35 to .47 millimeters.

Gaffney said part of the reason is one particular sand-pumping project in 2006 hit coarser grain sand at an offshore burrow area. He said the native sand is finer, but altering the grain size “probably will not work” in solving the problem.

Shortening and lowering rock groins was listed as a potential solution, but an expensive one. This would produce gentler slopes but might reduce beach widths. Gaffney said it is not a simple case of removing rocks. The groins would have to be rebuilt from the ground up. The city asked the firm to come up with cost estimates.

The engineers believe the natural slope was likely a one foot drop for each 10 feet horizontal, as it is now, but they did not have data going back to the turn of the 20th century, when jetties were constructed to create Cold Spring Inlet. The jetties blocked sand drifting south, widening Wildwood’s beaches and starving Cape May’s.

Longtime resident Herb Pharo said he has some data from that era and will give it to the city.

“You have to look at views from 1900, before that inlet was put in, and compare that to today. In 1900, we had a gradual slope,” said Pharo, arguing a large jetty off Cape May Point may be the answer.

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Information from: The Press of Atlantic City (N.J.), http://www.pressofatlanticcity.com

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