Special Bd. of Aldermen — 10/26/15 Page 18
Last one Mr. President, yes and the abatement | can understand that. Again, I’m thinking more nature erosion
time, five years down the road, ten years down the road.
Mr. Millan-Ramos On top of what we described already, there is also in consideration putting some sort of
wrip wrap in the existing edge of the river. We may or may not have figures showing that. We do? Do we?
Ms. Taylor And just to add on that, anytime EPA does an action where we are leaving waste in place, there
has to be an operation and maintenance plan, which would be in perpetuity. That is part of the negotiations
where we are going to figure out who would be responsible for that in the future. But there will be operation
and maintenance plan that needs to be implemented that will both check for whether or not there is any
degradation of the cap or any exposure of any materials or any further groundwater contamination that we
weren't expecting.
Mr. Millan-Ramos | just want to quickly show a depiction of what that wrip wrap and liner protection would look
like at the edge of the river. This was provided us graciously by Darrin Santos. And Darrin correct me if I’m
wrong, but the picture here below is an example of a retaining wall?
Mr. Santos That’s the panel retaining wall, we have shifted to do a full poured wall instead so we don’t have to
worry about the seams. But that is reinforced concrete so that would be above the secant wall.
Ms. Taylor And that material that is on the top, that is not like a containment unit, there is going to be grass
and other wetland species that grow through that. But that’s just to really solidify and keep erosion from
happening on the riverbank so you will have even less of an opportunity that a flood would wash that away.
Mr. Santos And | just wanted to add on the asbestos just so we have, well it is off the map here, but the City
property there is also asbestos in the southern parcel here of the Mohawk site that needs to be cleaned up at
the surface. The conceptual plan is to put it an containment rectangle behind that secant wall. So the
backside of the secant wall would form one side of the containment structure for asbestos. | shouldn’t have
said structure, it is going to be an excavation with a cap over it similar to how any site in Nashua is capped.
Further, the air monitoring — if Geolnsight works with the developer, we will have to have an air monitoring plan
written and approved by EPA and DES before we proceed and that would cover asbestos and any hydrogen
sulfide from the lagoon.
Mayor Donchess
One thing that | haven’t mentioned yet is that we did meet with the neighbors on the 13" which was several
weeks ago or so. There was some skepticism expressed regarding the capping solution and the request was
made that we, the City, engage someone to review the EPA’s findings as well as the cost estimates. We
fortunately have Sanborn Head.
Ms. Taylor Sanborn Head, we are very familiar with them, they do a lot of work for us too.
Mayor Donchess
Who does a lot of work for us at the landfill and they agreed and they have worked at this site before for some
reason. | think Ms. Belknap said that they did the work back in the 80’s or at some point. And anyway they
have agreed to review and they think they can do it quickly. So | think we have scheduled a meeting for
October 16" for them to meet with the Board of Aldermen and just present their conclusion.
