At the rear of the Sylvester Manor property, behind the manor house and near the creek, there is a small land bridge that leads to an area the Sylvesters called the North Peninsula. It’s a protected spit of land graced with fresh water springs where the Manhansetts once fished and farmed.
The land bridge is defined by a stone wall that, according to Sara Gordon, Sylvester Manor’s planning and conservation consultant, was reconstructed around 1909 on the site of a former 17th-century tide-powered sawmill spanning a neck of Gardiners Creek.
“We suspect it was a finger inlet, and the land bridge was built as an alternative way to get goods to the harbor,” said Sara Gordon in a recent phone interview. “But that’s a guess.”
One thing that isn’t a mystery is the fact that the land bridge is in trouble. Ms. Gordon explained that, according to Gunnar Wissemann, house and grounds manager of the property, the bridge has historically washed over about once a decade.
“High tide fills the creek and the water can’t exit. As far as we know, there’s a single carved square culvert, that’s the best Gunnar has been able to discern,” Ms. Gordon said. “There is flow, but it’s not a full flushing. The culvert is sound, but the super structure around it is not, and it’s too small to allow a healthy flow. The ebb tide from the lagoon is about two hours behind normal because of the volume of water.”
With sea level rise and storm intensity increasing, the land bridge is over washing far more frequently than it has historically, which is weakening the structure as well.
Enter the civil engineering students of Stony Brook University. As part of their senior design capstone project, all undergraduate students are required to design and engineer a real life solution to a real world problem.
“It’s about project-based learning,” explained Harold Walker, professor and chair of Stony Brook’s civil engineering department, by phone. “The big part for us and our students is they get to work on a real world project, like the one at Sylvester Manor.
“In addition to applying all the different things they’ve learned technically, we really try to highlight the professional skills,” he said. “Civil engineering is technical, but it’s also a lot about people and designing things for those who are using roads, bridges and buildings.”
For that reason, Mr. Walker notes, civil engineers don’t typically sit in cubicles. Instead, they are out in the field talking to stakeholders — people in the community who will ultimately use the structures they build.
“It’s a great opportunity for the students. I told the team, Sylvester Manor is the client and we want to exceed their expectations. They have constraints and a vision for the project, as engineers, our goal is to translate their needs and vision for this to project plans,” he said. “The students should be able to manage a project and communicate and take care of all the details.
“We’ll present it to Sylvester Manor, hopefully they’ll be excited and take what the students do to a professional engineer, and see what’s possible.”
Senior civil engineering student Donovan Li is project leader of the group working on the land bridge project at Sylvester Manor. On a recent Friday, Mr. Li and his peers traveled to Shelter Island to get their first look at the problem they will be working to solve throughout this school year. By May, they will have a design in place.
“Right now, the land bridge is sinking due to floods and the flow is not doing too well. We’re putting together the master plan which deals with design, costs, permits and stuff like that,” explained Mr. Li in a phone interview. “We’re going through a couple different designs, a lot of them centered on feasibility and aesthetics. We’re thinking to dig it up, replace the culvert with one or two larger culverts, bury it and keep the walking bridge the same.”
The primary challenge for the students is to fix the problem now and for the future, but do so in a way that is sensitive to the historic nature of Sylvester Manor. That means they need to plan for 1,000 year storm events capable of bringing in a few feet of tidal surge, yet retain the turn of last century look of the bridge.
“For the most part, there are two main designs we are putting forward — a slightly arched bridge, we have to follow the laws for handicapped vehicles, and another being a wooden bridge that is slightly elevated and can withstand the elements,” said Mr. Li.
While the plans for this project are purely theoretical at this point — these are undergraduate students, after all — if their final design passes muster with professional engineers, permitting agencies, and grant money can be found, there is a strong possibility that their design might ultimately be implemented as the fix for the land bridge problem at Sylvester Manor.
“It’s honestly pretty cool,” said Mr. Li who added that he recently read a book about the construction of the Brooklyn Bridge. “I love history and that’s one of the cool things about engineering. We saw older pictures of the culvert when it was bigger and nicer. For us to be working on something like this and able to be there and implement something new that’s a realistic possibility is exciting.”
The collaboration between Stony Brook University and Sylvester Manor came about when Mr. Walker met Ms. Gordon while working on the recent installation of new clean water technology at the Manor.
“We’ve gotten to know Sara and last time I saw her, I asked if anything at Sylvester Manor might need engineering,” said Mr. Walker. “She said, ‘All kinds of things.’”
“As an educational farm, the broadest definition of that term is our goal,” Ms. Gordon said. “We want this place to be available for study of all kinds, including collaboration at every level of education, from ages three years and up.”
After touring the property and learning more about the needs and potential projects that could be undertaken, Mr. Walker settled on the land bridge project as an ideal one for his students.
“The great thing about this project is the cultural side of it. There’s obviously a lot of history at the farm and it incorporates technology with social historic context,” said Mr. Walker. “The big challenge from a technology side is figuring out the hydraulics, both short- and long-term.”
In the end, this project will be a win/win both for the students who will gain valuable experience and Sylvester Manor which will get a set of plans that can be used to fix the land bridge for now and generations to come.
“It’s our first project at Sylvester Manor,” said Mr. Walker, “and we hope to have many more in the future.”