New London — The Connecticut Port Authority has agreed to a set of conditions requiring it to document and showcase a nearly 150-year-old, granite-lined pier being covered over as part of a $235.5 million construction project on New London’s waterfront.

The 1,100-foot long Central Vermont Railroad Pier, built in 1876, is being connected to the more modern adjacent pier as part of a plan to convert the two piers into one central wharf that initially will be used as a staging and assembly area for the offshore wind industry's turbines. The entire facility was designated in 1997 as the Adm. Harold E. Shear State Pier.

With a state permit approved, the port authority this week approved a memorandum of agreement with the U.S. Army Corps of Engineers and Connecticut State Historic Preservation Office that they believe helps clear a path for the federal permit.

One stipulation in the agreement includes a $100,000 donation to the nonprofit Ledge Light Foundation for repairs to New London Ledge Light. The port authority, as per the agreement, additionally will document with photographs and text all aspects of the pier, including any significant findings, as work gets underway and portions of the substructure are exposed.

The CPA, “if necessitated by the project,” will also develop a historic materials treatment plan “for the removal, dismantling, storing, repair and reconstruction of the granite block bulkhead walls and associated historic materials.” That stipulation is contingent on whether or not work is needed on the western side of the pier, a portion of which collapsed in 2014. All work and documentation are to be reviewed by CSHPO.

CVRR Pier was listed on the National Register of Historic Places in 2005 and believed to be the only remaining large 19th-century pier of its kind. The pier was constructed with earthen fill between granite retaining walls at a cost of $225,000 — $45,000 for a coal-handling facility and $175,000 for the pier.

“The coal facilities, finished in 1877, included a steam-powered hoist that could unload more than 100 tons of coal an hour from the Reading Railroad freighters in the slips in Central Vermont’s rail cars and coal bunkers,” according to the narrative in the application for the National Register of Historic Places.

By 1904, the pier was reconfigured to serve as a freight and express service to New York City, operated by the Central Vermont Transportation Company. Freight carried by rail to New London was shipped overnight to New York City. A rail line that once ran down the center of the pier was removed in the 1940s.

The state bought the CVRR Pier for $2.9 million in 2001 and recently transferred ownership over to the Connecticut Port Authority.

Historians still wonder about the source of the granite, one of the several questions about the pier that might be answered during the construction process.

“There are not many masonry piers from this time period on the East Coast,” said Catherine Labadia, a staff archaeologist with the CSHPO, the entity that helped craft the agreement with input from New London Landmarks.

Labadia said the loss of the structure will be mitigated by the plan for documentation, though the upcoming construction project may shed light on details about how the pier was constructed. She said engineers who worked on construction plans have done a good job in trying to retain as “as much of its historic fabric as possible,” which includes keeping some of the brownstone facade.

“When this project was initially proposed, CVRR Pier would have been unrecognizable,” she said.

In addition to taking photographs of the pier during construction, the port authority has agreed to develop a booklet with information about the pier that also will be posted on a website for the public.

The agreement fulfills a requirement of the National Preservation Act of 1966, which mandates federal authorities take into consideration how its actions will impact historic properties, Labadia said. The state's Environmental Policy Act has similar provisions.

The $100,000 to Ledge Light was added as a stipulation because of what she said was the need for something more tangible for the community. That money will be used for repairs to a boarding platform, masonry repointing, repair or replacement of glass in the lantern room and painting.

A spokesperson for the Ledge Light Foundation could not be reached for comment. Susan Tamulevich, executive director of the New London Maritime Society, which owns Ledge Light, said the funds will help preserve the historic and iconic treasure.

g.smith@theday.com