The Ponds

We are approaching the end of a long journey.  We are in the second round of NYSDEC questions about our project plan and are optimistic about having the approval of our project plan in the coming months.  The project has been made possible by the work of many, the contributions you have made, and the intervention of an extraordinary violent storm in August of 2014.

In 2005, the park board committed to reversing the deterioration of the ponds as our number one priority.  The problem, simply expressed, was that in the warm weather the ponds were choked with green stuff, algae we thought.  Each July and August was worse than the last.  To any observer, the ponds, a key architectural feature of our community, were headed toward becoming bogs.  We had no idea how difficult that would be.

We imagined, as many folks do, that this was simply a matter of high nitrogen levels caused by fertilizer runoff.  We thought aeration, circulation, chemicals, magic machines, and herbicides would solve the problem.  How hard could this be?  We were blessed with talent, and, under the guidance of Chuck Hamilton, former Regional Enforcement Office of DEC, with the help of Margaret Conover, botanist, and environmentalist, and with a pro bono contribution of effort from Marian Wypyski, an engineer from Lockwood, Kessler, and Bartlett, we began root cause analysis.

We studied the tributaries to the pond and discovered their scope was well beyond what we had imagined, ranging from 25A to the east to Quaker Path on the west, and well out into the contours of the St George’s Golf and Country Club to the south.  We did turbidity studies using volunteer observers to track the mud that flowed into the pond in heavy rains.  We also retained H2M to conduct sediment studies, expecting to find nitrogen and, given the amount of road runoff, heavy metals.  No significant trace of pesticides.

What we found was that the problem is essentially mechanical.  We do not have high nitrogen levels.  We do not have heavy metals in any significant concentration.  What we have is a shallow pond that has filled in well beyond its design and historical depth.

That green stuff we are looking at, choking the ponds in the warm weather is not algae; it is Elodia, an invasive plant that is firmly rooted in the bottom.   Elodia, once introduced, will grow in freshwater ponds shallow enough that the sun reaches the bottom.  So harvest it, kill it, poison it, wish it away with magic, it will grow and overwhelm the ponds, so long as the bottom is shallow enough to provide it with a place in the sun.

The solution:  return the ponds to their design depth.  These ponds were man-made in the late 1930s.  Without that design, what we have is a narrow wandering stream and a mud flat.  Without restoration, what we have is a bog.

Historically, before environmental regulation, the Melvilles used to drop the gates, drain the ponds, let them dry out, and run heavy machinery around to clear out the dead vegetation.  If you did that today, there would be guys in helicopters rappelling down in black suits to cart you away.

So, easy enough, the solution is to dredge.  Float a small barge out on the pond, and begin at the upper (southern) end.  Take out the excess material that has filled in the ponds.  Restore the historical depths.  This is proven technology.  Put out a small barge.  Work a dredge line back to a dewatering point, and suck up a slurry of sand, organic material, and water.  Design it so that fish, turtles, birds and benthic life will not be heavily impacted.  This is a well-navigated territory with established methods and contractors.

And yes, since you ask, we will adapt to the fact that our ponds have become a stopping over the place for migratory birds and that the restoration has to allow for resting and feeding places not contemplated in the original design.

But, before we do that, we have to identify the root cause.  We understood that DEC would never let us undertake a high-impact project that would have to be repeated 10 years later.

Why do the ponds fill-in?  Where did enough material to fill in ponds with a design depth of 8 feet to, in many places to 18 inches come from?  Back to the turbidity studies and the walking surveys and lots of volunteers walking around in the rain.

The bottom line, the culprit is road runoff.  Some contributions from the farm, but mostly the sand put down on the roads to keep us safe in winter washing into the ponds.  So, before we can do anything, we need to reduce the impact of this runoff.  Working with Brookhaven Town, cascade systems were installed to filter the runoff from Main Street, Old Field Road, Mud Road, Christian Avenue, and Ridgeway.  Suffolk County mitigated the runoff from the farm, installing two recharge basins.

So, all good, but for a mechanical problem, we have a mechanical obstacle.  The volume of material, a mixture of sand, dirt, and decomposed organic material as well as some dumping that has taken place,  to be removed from the pond is in the tens of thousands of cubic yards.  This is where we hit the wall.  Where do you put it?  You can’t put it in trucks when it’s wet.  It’s too heavy.  It has to be pumped out and allowed to dry out. Dewatering they call it before it can be trucked.  And then when you truck it, where do you dump it?

We evaluated options.

First, we looked to see if there was any area of the park where we could put this material or stage it for dewatering.  Not so much.  Pretty much everything north of Mill House is sensitive salt-water wetlands.  And the trees beyond the community gardens were magnificent elms that could not withstand the dumping.

Could we borrow the school field and pump it up there?  Pump it into the recharge basin up by 25A across from Stop and Shop?  Assuming the cooperation of the Community Trust, clear-cut the Norway Maples behind Patriot Rock and use that as a staging area, ultimately restoring that area to a William Sidney Mount depicted meadow.  A major project with a high impact on the community.  Our best option was to build an island in front of the Neighborhood House and dewater it there. Machinery running 24 hours a day, traffic disruption.  Disruption of the Neighborhood House party and cultural schedule?  End of the day, we were stymied.

Any of these options was high impact, involved crossing a major roadway, disrupting traffic, and represented engineering challenges.   Then came the mesocyclone or microburst of August 4, 2015, which destroyed our beloved elms and left us with invasive and low-value trees on the east side of the park.  From lemons we make lemonade.  Now we have enough room to dredge and contain and dewater most of the material on site.

And we will be able to re-contour the site, when all is done, in a way consistent with the designer’s architectural vision and historical norms.

Our application is in with DEC.  We are in the second round of comments.  They are concerned, appropriately, that the dredging reaches the design bottom or that we identify what the bottom will be if we don’t go deep enough.  They are concerned that the water draining back into the bond will be properly filtered.  And on and on.

After this round, we will begin to present our plan to the community, uniquely rich in expertise, for comment.

Sincerely,

Tim Glynn
Chairman Pond Restoration Committee