Army Corps of Engineers Proposes Plan for New Haven Flooding

The area had damaging flooding from Superstorm Sandy and Tropical Storm Irene, and such storms are expected occur more often, said the report. Sea level over the next 50 years is expected to rise 0.4-3.2 feet in New Haven.

by Mary E. O'Leary, New Haven Register, Conn. / January 16, 2020
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(TNS) — The U.S. Army Corps of Engineers is recommending a system of flood walls, flood gates and pump stations be constructed along Interstate 95 in the Long Wharf area to reduce damage to businesses and railroad property from flooding over the next 50 years.

The recommendations are contained in the corps’ Coastal Storm Risk Management Feasibility Study that builds on the city’s Long Wharf Responsible Growth Plan adopted in 2018, as well as GZA’s Flood Protection Study undertaken in 2016.

Long Wharf is home to businesses that represent 5,000 jobs and, with protection, the area is expected to continue to provide future economic benefits to the city despite the threat of flooding and sea-level rise due to the low elevation compared to the rest of New Haven, according to the report.

The corps is inviting public comment on the risk management study by Jan. 20. Comments can be directed to Project Manager Byron R. Rupp at his email, Byron.R.Rupp@usace.army.mil or by phone at 978-318-8172.

Rupp has agreed to a webinar/phone meeting to answer questions from City Point/Oyster Point residents this week with the date and the time to be announced.

This is a single Army Corps of Engineers project being studied for feasibility and is not intended to represent a comprehensive flood protection strategy for New Haven, according to City Plan Director Aicha Woods. It is not a city of New Haven project.

It was chosen by the Army Corps based largely on its ability to protect critical infrastructure of national/regional significance such as the interstate transportation system (I-95 and the rail yards), Woods clarified.

In answer to the concern of the City Point residents, Woods said the corps did not find adverse effects to the neighborhood. If they had, they would have had to offer mitigation. They were concerned because it looked like the neighborhood is in front of the flood wall.

They also want more details on the height of the wall, estimated at 15 feet, as well as its appearance, and potential property acquisition.

The project has been under consideration throughout the initial Long Wharf Flood Protection study commissioned by City Plan in 2016 as well as the Long Wharf Responsible Growth Plan.

The protective measures would extend for 6,425 feet along the I-95 embankment at Long Wharf. The corps is predicting that there will be a less than one percent chance storm surge would breach the flood protection measures. The measures are expected to protect the property and businesses from storm surge up to 15 feet above average sea level.

The Project First Cost includes initial construction, a risk-based contingency, pre-construction engineering and design, construction management, and lands, easements, right of ways and relocation costs estimated at $164,612,000. Operation and maintenance costs would be around $1.65 million per year, with the federal government covering 65 percent of the total project.

The specifics of the recommendation include:

Road closure structures (one at Long Wharf Drive approximately 60 feet wide by 4 feet high; one at Canal Dock Road approximately 130 feet wide by 5 feet high; one at Brewery Street approximately 65 feet wide by 2 feet high; two at Exit 46, (approximately 50 feet wide and 6-8 feet high). The pumping stations would handle approximately 400-500 cubic feet of water per second (cfs); enhancement of the I-95 embankment with approximately 5,950 linear feet of “T-wall” type flood wall along with 475 feet of deployable closure structures; and potential floodproofing of commercial and residential structures seaward of the I-95 embankment.

The area had already experienced damaging flooding from SuperstormSandy and Tropical Storm Irene, and such storms are expected occur more often, according to the report. GZA’s Flood Protection Study found that sea level over the next half-century is expected to rise between 0.4 foot and 3.2 feet in New Haven.

“In 100 years, sea levels may be high enough that today’s Long Wharf would flood twice daily. However, these outcomes can be avoided. The Long Wharf Responsible Growth Plan proposes resiliency measures to protect flood-prone areas,” according to the corps.

The study area contains “more than 100 high value structures, the majority of which are classified as commercial. Key infrastructure includes the New Haven Rail Yard and Interstate 95, each of which dominates access in and around the city and surrounding region. The total value of New Haven’s existing industrial and commercial inventory analyzed within the Long Wharf study area is estimated to be worth over $780 million.”

Areas and structures, in addition to I-95 and the railyards, impacted by flooding include: Wooster Square; the Downtown Crossing; Union Station; Church Street Connector; the Hill neighborhood; Long Wharf Theatre; such companies as Assa Abloy and Jordan’s Furniture; the Long Wharf Pier; Long Wharf Nature Preserve; Sound School

Structures left out of the system would be eligible for alternate flood-proofing measures, but Woods said there are other more cost effective routes that do not involve the Army Corps. She said it is best at large infrastructure rather than residential scale modifications, especially in a historic district.

The Long Wharf Responsible Growth Plan creates five districts with new streets and a greenway designed to absorb storm water. Also part of this is an $8 million Living Shoreline project that improves park space, habitat for shellfish and shorebirds and restores marsh and dune habitat that will act as a natural barrier.

The hope is that if FEMA determines that flooding is no longer threatening the area, it would revise its flood insurance rate maps and cut the cost of owning property at Long Wharf.

Read the full report:

Draft Main Report EA 13DEC2019 by Helen Bennett on Scribd

mary.oleary@hearstmediact.com; 203-641-2577.

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