With summer approaching, Oak Bluffs officials are reacting to questions about the quality of the dredge spoils used to nourish Inkwell and Pay beaches over the winter in an effort to replace sand lost to erosion. The spoils — mostly black, compact sand — came from the dredging being done in conjunction with the construction of the new Lagoon Pond drawbridge.
State officials and executives from Middlesex construction company, the general contractors for the bridge project, agreed to take action “in the next few weeks,” Melinda Loberg of Tisbury, chairman of the Lagoon Pond Bridge committee, told The Times.
Ms. Loberg made a site visit to the beaches early last week with Oak Bluffs selectman Walter Vail and Oak Bluffs conservation agent Elizabeth Durkee. Ms. Loberg took samples of the suspect soil to the bi-weekly meeting of the Lagoon Pond committee last Wednesday.
The sand substitute has been a topic of discussion since it was deposited at the beaches in February. At the time, town officials said that the dredged material would bleach out by summer. However at a meeting of the selectmen on April 22, seasonal Oak Bluffs resident Richard Seelig presented town officials with a sample of the soil that was black in color and clay-like in texture and also contained various rusted metal objects. “This will never bleach out,” Mr. Seelig said, holding up a rusted welding rod.
Initially the dredge spoils from Lagoon Pond bridge were destined to be landfill. On February 24, after testing the material for heavy metals, Ph levels and grain size compatibility, the Department of Environmental Protection (DEP) amended the permit to allow the dredged soil to be used for “beach nourishment material” in Oak Bluffs.
“The reason the material was originally going to be placed in a lined landfill is due to the conductivity levels,” Ms. Durkee wrote in an email to The Times. “Ken Chin at the DEP explained to me that the high conductivity has to do with high salt content, which would be a bad thing to leave in an unlined landfill because the salt could leach into the groundwater, but on a beach — it’s salt, same as in the ocean — it’s not relevant. These are tests required in order to get permits to use dredge material for beach nourishment. I was vigilant about making sure it met the [DEP] criteria before a spoonful of sand was placed on the beach.”
“It’s not a perfect fit,” Mr. Chin said in a phone interview with The Times. “But the town was desperate for beach nourishment material and the sediment passed all the necessary tests. If there are metal objects, that’s the responsibility of the contractor.”
Rock and a hard place
“The stuff contains more clay than we were led to believe by the bridge contractor,” highway department superintendent Richard Combra said. “It’s not what we had hoped we were getting. If we get down to June 1 and it hasn’t bleached down we’d consider moving it.”
Mr. Combra said dredge spoils that have been used for beach nourishment in the past have always bleached out. He added that a large amount of ocean sand will be deposited on the beaches after Little Bridge is dredged in early June.
“The Lagoon Pond sand has been underwater for a long time — longer than, say, sand dredged from the Sengekontacket Pond inlets,” Ms. Durkee said in an email to The Times. “Thus it contains more organic matter and takes longer to break down.”
Ms. Durkee and town officials currently have limited options in the battle against beach erosion. “The Division of Marine Fisheries prohibits mining sand from the ocean, which is permitted in most states.” she said. “There’s an active movement afoot to change that.”
Ms. Durkee said there are plans to replenish town beaches down to the mean high tide mark, but they too face a gauntlet of federal, state and local regulations. “The permits we are pursuing will allow the sand to be placed below high tide — out into the water — this will widen the beach, making it bigger for better recreational use and for better protecting the road and houses behind the beach from storm damage and flooding,” she said.
Another fix Ms. Durkee is working on for Inkwell and Pay beaches is to lengthen the jetties to allow sand to naturally build up. “Years ago the groins were put in place to protect the beaches. They protect one beach but starve the beach to the south. We’d like to lengthen the groine at the Inkwell, which will keep more sand there naturally.” Ms. Durkee noted that an extended groin at the Inkwell would also help reduce the buildup at the Farm Pond culvert. The town currently spends $15,000 a year to dredge the Farm Pond culvert.