Designing Lawrence village’s flood mitigation project

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An $8.776 million drainage improvement project for the Village of Lawrence is expected to have a shovel hitting dirt in the summer of 2020, according to Nassau County officials and the engineers from the firm LKMA.

The Brookhaven hamlet-based engineering firm is designing what will be done in an effort to reduce flooding in the 287-acre watershed area that extends from the Lawrence Long Island Rail Road station to Bannister Bay.

County Deputy Planning Commissioner Sean Sallie, LKMA Senior Project Director Gilbert Anderson and LKMA designer Bob Steele discussed the proposed project at the village board meeting at the Lawrence Yacht & Country Club on Feb. 14.

Specific streets in Lawrence village are well known for flooding during rainstorms and the homes on those are severely impacted after heavy rains and hurricanes. Barrett and Marbridge roads, Harrison and North streets and Meadow Lane were highlighted in the Five Towns Drainage study that was conducted nearly four years ago.

“In the drainage study, we identified high priority flood projects,” Sallie said. In addition, those streets were surveyed during a rainstorm on Jan. 24 and during high tide the following day. Photographs illustrated the extent of flooding on both days. Collecting survey data began in November 2018.

Anderson said that through the 20th century — the 1920s, the 1940s and the 1960s especially — the most development occurred in that Lawrence watershed, literally placing more pressure on the existing system. “As the area has developed the system was more and more hard-pressed to transport the water,” he said.

By installing a 60-inch pipe, a series of new pipes and constructing a box culvert — a large rectangular pipe — to run parallel with the new large pipe, the goal is to increase the water storage collection points — catch basins — and the speed of water drainage.

“We are going to design the system for the highest intensity rainfall we can,” Steele said, adding that the design could include the “best place for tidal gates,” in response to a question from a village resident. “We are looking to have enough opening to capture the water coming down.“

The work, which is in the design phase, is expected to begin on Meadow Lane, south of Broadway, and stretch to the end of Causeway, south of Rock Hall Road, by the Lawrence Yacht & Country Club, officials said. The design phase is anticipated to be completed by November. “We choose one [plan] that would have the most cost benefit,” Anderson said.

When the work does start, it will involve pulling up manhole covers, ripping up the roadways and, according to Anderson, it will be “intrusive” but they plan on being “in and out as soon as possible.”

The process is design, fabrication and installation. The county, which is in charge of overseeing the project and money will bid out the project and select the lowest responsible contractor and the best-qualified company to do the work. “We will inspect the work,” Anderson said.

Sallie said that cost overruns are the county’s responsibility and a contract will be drawn up to dedicate the system to the village and which entity is responsibility for maintenance of the pipes.