Park Volunteers Manage The Bends In The River

Sunday marked the first cold morning of the year, with rain, and at the Edgewood Farmer’s Market, people hurried from stall to stall. But another group of people gathered at the gazebo and soon headed farther into the park, unharried by the weather. The occasion was a walk of the New Haven Bioregional Group, into a part of the city where trees and moving water had something to do with preparing the Elm City, and the region, for the future.

The walk had a dual purpose, as Nicole Davis of the West River Watershed Coalition and Save the Sound explained. The first was to draw attention to the work the Friends of Edgewood Park has been doing in the past few years in maintaining trails, taking the vines off young trees to allow them to grow, and planting new trees. The second was to talk about the beginning of a new project in the park, conceived under the auspices of the West River Watershed Coalition, to shore up the banks of the West River at certain points in the park while also maintaining it as a sponge for floodwaters. 

“So we’re looking at two legs of the park,” Davis said, ​“the land in the park, and the people side of it — what people see and use all the time — and also the river, thinking about what we’re doing in the city of New Haven and in the park itself to impact the watershed that we live in.”

In the course of the walk, these two purposes converged to give participants a glimpse into the history of the park and into a few key ways in which — whether by design or accident — New Haven managed to get the balance of development and conservation in the area right.

Frank Cochran, of Friends of Edgewood Park, began by talking about the organization’s Green Team, which started eight or nine years ago, according to Cochran, and meets every Tuesday morning throughout the year to do ​“guerrilla park maintenance.” The park ​“needed a lot of work that wasn’t getting done by anybody,” he said. ​“But it also needed some trails to be created,” and it was necessary ​“to keep a good eye out for issues as they come up in the park.” Its main activities include trail maintenance, planting trees, and ​“de-vining,” Cochran said, ​“which is really the most interesting civic activity I know of.” Young trees, he continued, ​“are really beset by vines,” and by setting them free, they can grow into healthy adult specimens.

As the walk began, Cochran explained that the river’s course had been straightened during the park’s development by the building of a berm on its bank, which created dry land to the east and wetlands to the west. That dry land encompasses the skate park and the paved north-south path running the length of the park. On the other side of the berm, ​“there are a lot of places where it’s old swamp, and that’s good,” Cochran said. ​“This is a floodplain, and it works very well as a floodplain, so this is not something we’re trying to change. But we are trying to adjust human stuff so we all can enjoy the river.”

Thanks to the berm, with rare exceptions (such as a flood in 1982 that turned the entire park briefly into a lake), the dry land actually stays dry, as the berm diverts floodwater into the swamp, which has a lot of capacity to receive it. The berm, in turn, is secure thanks in part to the trees and their root systems growing in it. So keeping vines from choking the young trees on the berm isn’t just about the health of the trees; it’s about helping keep floods at bay.

There are seemingly ​“millions of vines, and millions of trees,” Cochran said. Cutting vines is ​“an endless process, but it seems to be pretty positive … it’s a big project and it’s working” — particularly on the trail along the berm the Green Team has created, which grants walkers access to the water’s edge for much of the length of the park. (About the creation of that trail, Cochran deadpanned, ​“nobody said no,” and ​“we wouldn’t have listened if they had.”)

The walk reached the end of the berm, where another bridge (soon to be replaced) spanned the river. Cochran pointed out that the Green Team has shored up the riverbank there by planting willow trees, which have proven to do well in the park — so much so that a volunteer has sprouted in a pile of logs in the middle of the river near the bridge in the middle of the park. ​“You can plant a willow just by putting a stick in the ground,” Cochran said. ​“It doesn’t always work, but it does sometimes.” Red oaks and dogwoods have also succeeded, if the vines are kept off in their adolescence. 

But, as Cochran pointed out, there are places where the river is eroding its banks anyway, undercutting tree roots, on both sides of the bank. A river moving its banks is perfectly natural; during large floods, rivers have been known to dig new channels and create entirely new flow patterns.

In a particular part of the park, however, the river’s erosion is creating a problem — though perhaps one with a solution, explained Elsa Loehmann, an engineer with Fuss & O’Neil, a civil and environmental engineering consulting firm working with the West River Watershed Coalition. Analyzing the problem begins with looking at the entire West River watershed, which encompasses seven towns from its source in northern Hamden, pulling in far more water than it might first appear. ​“That’s why this storage area” — for floodwaters — ​“that we have over here in these wetlands is so important. That’s also why we’re starting to see all this widening trying to happen in the channel. The widening itself is not necessarily a bad thing. We’re going through this period of time where we have increased precipitation, so there’s more water in the rivers.”

The problem to solve, as Loehmann saw it, was in the time scale of the river’s change in adjusting to the wetter enviroment. ​“Rivers are used to adjusting on geologic time” — that is, very, very slowly — ​“and we’re telling our rivers that they need to adjust in 20 years. And these systems are just not built to adjust that way, so it looks kind of messy.”

The mess is evident in the river’s eroding bank, which is slowly encroaching on a section of the paved trail that runs the length of the park near Edgewood Avenue. That erosion was hastened by the recent deaths of ash trees along the riverbank due to disease. When the city removed the dead ash trees, it took out the root balls of those trees as well, leaving the remaining bank even more vulnerable to erosion from the river. ​“It just left these big gaping wounds on the side of the channel, that’s already trying to widen, and it just took advantage,” Loehmann said.

The solution, however, may lie in understanding that the ash trees’ roots were holding the bank together before they were removed. Loehmann also knows that this solution will have to be implemented by volunteers. So she’s turning to a method known as branch packing. ​“It’s very low intensity,” involving putting down soil and live plant matter, then a carpet and seeds, held down by stakes. The idea is that eventually plant life will take root and hold the bank in place. The Greater New Haven Green Fund has supported the first phase of the plan’s development. Loehmann estimates that actual construction will require between $10,000 and $20,000 for materials and machinery to install it.

Meanwhile, gazing along the entirety of the bank, Loehmann asked, ​“what can we do to keep this from happening in the future? Really, the vegetation is so important here,” ranging from planting shrubs to leaving the root balls of any other dying trees.

Looming over the questions about managing the river’s flow — and tying back to Cochran’s comments earlier — is the prospect of the park absorbing another 100-year flood, as in 1982. In some sense good news lay there. ​“For a 100-year flood, this entire park is underwater,” Loehmann said. ​“And that’s as it should be. These areas were meant to be our city’s sponges.” As a few participants pointed out, whether by accident or by design, New Haven managed to leave the river floodplains of the West River and Mill Rivers largely unbuilt, leaving them as parks. In the face of rising tides, sea levels, and precipitation in the future, both East Rock Park and Edgewood Park are helping New Haven be ready.