By DAVID NAHAN/Sentinel staff
OCEAN CITY – Ocean City officials presented an “ambitious” but “achievable” $25 million, five-year plan of flood-mitigation projects across the island.
In a virtual Zoom presentation Saturday morning from City Hall, city business administrator and engineer George Savastano reported on what has been done over recent years to deal with flooding and what is planned for the next five.
He followed Carol Beske of ACT Engineers, Inc., the private firm that has handled most of the flood projects on the island in recent years. Her part of the presentation was about the factors that go into deciding how and where flooding is occurring on the island and how to mitigate that.
“Overall, what we’ve prepared is a plan to address the bulk of the major flood-mitigation projects over the next five years,” Savastano said. “We’ve done much already, I’d venture to say more than any other barrier island. To get to this point has involved the expenditure of thousands of hours of work.” He said the work to come will involve thousands of hours more “and a considerable expenditure of funds.”
He expects the upcoming work to cost in the neighborhood of $25 million.
He added that work will be blended into the overall capital plan so that it won’t compromise other projects, including the planned public safety facility that will house the police and fire departments where the fire department headquarters is located at Sixth Street and Asbury Avenue.
Savastano said the scope of the projects is “ambitious” but “achievable” from a funding and engineering standpoint.
Savastano noted public and private efforts so far to make the island more flood resistant have allowed property owners to get 30 percent discounts on the flood insurance because of the improved National Flood Insurance Rating.
“We want to have programs and infrastructure in place to ensure the best quality of life,” he said.
The aim is to manage and control flood water, prevent flooding “to an achievable point,” make sure new homes are built we’ll above severe flood levels, ensure systems can handle minor and moderate events and to let citizens know “where and when we’re vulnerable.”
Savastano said in the northern half of the island, Ocean City’s most vulnerable low-lying areas are centered on the Haven and Simpson avenue corridors along with west 17th Street, which suffers from chronic flooding.
Two major areas that have been addressed with pump stations and piping are in the corridor at First to Eighth streets and 26th to 34th streets. Three pump stations were installed in the first area and four in the other.
Conditions related to chronic flooding in those areas have been “greatly improved,” he said.
The areas to be addressed in the next several years with piping and pump stations are west 17th Street, Ninth to 18th streets and 18th to 26th streets.
A project is currently under design in the Ninth to 18th streets area. Construction is expected to take place between the fall of 2021 and spring of 2022.
The city is coordinating with New Jersey American Water to address west 17th St. because the water company has plans to relocate its sanitary water pumping station, along with replacing sewer and water lines throughout the neighborhood. That work is planned for construction from fall 2021 through spring 2022.
The city, he said, will follow that with its own stormwater pumping project anticipated to go to construction in fall 2022.
From 18th to 26th streets, work to install new pump stations is expected in fall of 2023.
The South End
Savastano said from 34th Street to the southern end of the island there are three distinct zones most impacted by flooding – Merion Park, the corridor along West Avenue from 34th to 55th streets and the Ocean City Homes neighborhood at the southwest end of the island.
The city already did work in Merion Park with three pumping stations and drainage and raised roads on west 55th Street and 52nd Street. The city also did some work along West Avenue to deal with drainage and flooding including elevation of the roadway and installing check valves.
In “the next several years,” Savastano said, the city plans to have a second phase at Merion Park, West Avenue and Ocean City Homes.
The time frame for Merion Park is design in 2021 and construction in 2022.
For the West Avenue corridor, studies have ruled out using the old railroad berm. “Quite frankly, simply filling in the existing breeches will not mitigate flooding,” Savastano said. Instead, the conceptual plan is for road elevation, retention walls and stormwater infrastructure. The work will require coordination with Cape May County because part of West Avenue is a county road. Because of the complications involved, that work isn’t expect until 2023 to 2025.
There is a conceptual plan for the Ocean City Homes for raising roads, berms, retention walls, replacing piping and check valves and is expected to be done in the 2022-24 time frame, he said.
Understanding the flooding factors
ACT Engineering’s Beske, the company’s founder and director of public involvement, started the morning presentation, offering some statistics from the New Jersey 2019 Science and Technical Advisory Panel (released by Rutgers University). It set the following benchmarks for flood-mitigation planning:
– Sea level has risen 17.6 inches along the New Jersey coast since 1911.
– Sea level along the coastline rose 8.2 inches since 1979.
– Sea level predicted to rise 0.2 to 0.5 inches per year over next 30 years for a total of 6 to 15 more inches.
Beske said among the tools used in the city is high-definition LiDAR topographic mapping that can mark elevation of all surfaces in the resort.
It can measure all topographic surfaces from roads to buildings to get accurate elevations. It can help track flooding.
She said a “significant factor” to evaluate flooding is the tidal influence on the shallow groundwater table, along with the impact of precipitation and the efficiency of the stormwater system.
“Many of you have commented about water coming up through the ground around your house, in your yard, on your streets,” Beske said. “This impact needs to be quantified.”
She also talked about rainfall’s effect.
“On a low-lying barrier island, precipitation adds to the complexity of flood-mitigation planning,” she said. Because storms appear to be getting more frequent and more intense, the study has to include the impact of different types of storms, such as dealing with one inch of rain over six hours versus one inch of rain over 12 hours. That, she said, affects the drainage in the neighborhoods.
Planning has to consider the condition of pipes and their capacity to see if they can handle tidal flooding and storm flooding.
She talked about how nine piezometers have been installed in the Merion Park neighborhood to monitor groundwater level and that piezometers are being considered for other areas of the city.
Beske offered a chart showing how the combined impacts of precipitation and tidal events raise shallow groundwater levels to contribute to the surface stormwater flooding.
“Tidal impact alone,” she said, “can elevate groundwater levels to cause sunny day flooding in multiple areas of the island.”
Another important factor on flood-mitigation planning on the island is land subsidence – the gradual settling or sudden sinking of land. She said if residents see a manhole cover that once was level with the roadway but is now sticking up, that is an example of subsidence.
All told, she said, multiple factors help determine what strategies are needed, such as replacing drainage pipes, adding new pump stations or increasing their capacity, supplemental drainage inlets, raising sidewalks and roads, bulkhead repair and raising elevations. She said the comprehensive plan the city has established sets benchmarks to deal with the challenges of addressing flooding in the city.