December Construction Update
The Library Planning and Building Committee met Monday December 2 and approved several change orders, which were brought to the Select Board for approval.
The construction team met Tuesday December 3, 10, and 17, with CTA Construction, OPM, Clerk of the Works, and DRA Architects.
The stackbox was demolitioned at the end of December; photos are online at https://business.facebook.com/pg/GraftonPublicLibraryMA/photos/?tab=album&album_id=2702108553178920.
A significant part of December was spent with soil and groundwater testing. We’ve known from the beginning that there was a high likelihood for environmental cleanup – between the oil tank that was used by the Library and local lore that there was a gas station on the site, we’ve been expecting to find something. During the initial excavation following demolition, it was noted near the building that there was a petroleum odor. Because of this, we stopped the work and quickly brought in a Licensed Site Professional (LSP) who is experienced in remediation projects and could lead us through the necessary steps.
Working with the site contractor (who has their own LSP), the design team and construction team, we pulled together a draft plan to keep the project moving. Ten locations across the site (2 in the detention pond and 8 in the building footprint) were identified for testing and 10 soil samples were taken in each of those 10 locations. A quick groundwater monitoring station was also created and water samples were taken.
It was determined that petroleum was present in some locations at varying amounts – not in large amounts (in fact just over the level designated as “recordable”) but just the same, present.
The team has carefully gone through the steps to notify the DEP and EPA and created/submitted the appropriate paperwork based on the soil tests that were performed.
By January, we identified three different landfills (lined, unlined and no contaminants) that will receive the different types of dirt to be exported from our site and have completed the required paperwork.
Steps for end of January and into February are to complete a groundwater management plan which includes regular testing of groundwater on site as well as a system to clean groundwater that will be removed from the site and discharged into the storm drain system. This groundwater management plan is based on water sampling done on site and will be submitted to the DEP per regulations.
We expect the DEP review process to take 2-3 weeks once submitted; the team is ready to file their plan in the next 1-2 weeks. Then excavation can re-start.
We don’t have a good estimate yet on the additional cost to send the dirt to the three landfills but are hoping to have that shortly. The team performed due diligence and look at a potential ‘Plan B’ to see if we could find another path that could mitigate cost. The proposal was to:
- Change the foundation system from spread footings to aggregate piers
- Increase the thickness of the vapor barrier below the foundation
- Install a below-slab ventilation system similar to a radon system
The benefit to this is that there is very little excavation as the piers don’t require mass removal of soil, so the cost to excavate and truck away the material would not be incurred. The biggest downside is more political/optics than practical – impacted soil would remain under the building and while every measure would be taken to mitigate any risk and to meet all State and Federal requirements, the fact would remain that the building was constructed on top of contaminated soil.
After talking with both Tim McInerney, Beth and Mark Sullivan we all agree that continuing with the original plan to remove and replace the impacted soil is the best course of action.
Other activities related to construction have been continuing at a good pace – submittals are being reviewed and approved, RFI’s are being asked and answered and in general the team is doing everything possible to be ready to run as soon as we have gotten over these early hurdles.
Building Committee Minutes
December 2, 2019