Water And Soil Challenges At Wildwood And Fort River Sites Similar And Solvable
Preliminary concept for a three story school at the Fort River site, one of two sites being considered for a new elementary school. Photo: amherstma.gov
Wildwood and Fort River sites present similar challenges when it comes to constructing a school — but all are solvable, according to comments made by Geotechnical Engineer Mike Talbot of O’Reilly, Talbot & Okun, and Civil Engineer Janet Bernardo of the Horsley Witten Group at the Elementary School Building Committee (ESBC) meeting on April 22.
High groundwater and poorly draining soils are features of both sites, said Talbot, in a presentation to the committee on the geotechnical aspects of the project. The Fort River site is composed primarily of river valley clay, while Wildwood is predominantly glacial till, both soil types that do not permit infiltration of water. The high groundwater and impermeable soils cause water to run along the surface, making the conditions wet and muddy, Talbot said. With groundwater just ~1’ to 4 feet below the surface at Fort River and ~2’ to 5 feet at Wildwood, Talbot outlined approaches that would ensure any future construction would be protected from moisture infiltration, which included installing sub-slab drainage as well as air and vapor barriers. He also proposed sub-drainage for playing fields. For new construction at Fort River, Talbot recommended raising the grade by about two feet. “Raising the building solves a lot of your problems,” he said.
“In no way is the Fort River site unusual in the Connecticut River Valley,” Talbot said, sharing that all the playing fields at UMass have similar soil conditions. Referring to the Easthampton High School project completed in 2013, Talbot said, “that site had many of the same issues and concerns and the school has been around for 10 years and has operated without any problems.” Built in a swampy area, the high school building was raised four feet to mitigate moisture concerns.
To manage stormwater runoff from the roof and paved surfaces at either site, Bernardo said they would divert the flow away from the building and utilize constructed wetlands and bioswales with plants and vegetation, to detain the runoff and provide water quality treatment before it flows to the Tan Brook (Wildwood) or the Fort River. Existing culverts would be videoed to check they are structurally sound. At Wildwood, the culvert runs underground from a pond across from the entrance on Strong Street, under the driveway and parking lot, and toward the Middle School. At Fort River, they would propose “daylighting” the culvert, that is, opening up buried sections and making it an educational and site feature.
One of the issues at Wildwood, Talbot said, is that the hilly site was leveled when the current school was built, and up to 10 feet of fill was placed below the foundation and playing field. “[This fill] is highly variable and loose in some areas, and is not a suitable bearing material for a new building, so you would have to treat that soil,” Talbot said. He outlined two options for soil improvements: 1) excavating the existing soil and recompacting it in layers, or 2) driving in aggregate piers to densify the soil, analogous to a pin cushion that stiffens when pins are inserted. “Both solutions are reasonable and viable. It’s a matter of cost,” Talbot said. Rammed aggregate piers were also suggested for improving the load-bearing capacity of soil at Fort River. To address settlement, Talbot said they can preload and compress the soil before starting construction, an approach that worked well in Easthampton and other places.
In addition to groundwater, soils, and stormwater, another factor related to the site is where a ground source heat pump (‘geothermal’) well field could be located. The 31.5 acre Fort River site offers ample room on which to locate a wellfield; however, finding room on the smaller (14.3 acre) Wildwood site, particularly in a new construction scenario, is more challenging. For this reason, the design team has been looking into using the middle school field below, which would require a legal agreement with the Regional School District which owns the property. The designers have also considered using that field for play space for Wildwood students as level playing fields are minimal on the Wildwood site, but the ~15-20 foot slope and the length of ramp that would be required to make it accessible [stretching from the Head Start traffic circle to the middle school tennis courts] make it very challenging, Rick Rice of DiNisco said.
Due to topographic limitations on the site, the footprint of a new school at Wildwood would need to be located in the southeast corner of the site, requiring excavation into the treed hillside below Hills Road, and the construction of a retaining wall and additional drainage. Against that backdrop, and noting the likely costs cutting into the hill would entail, Committee Chair Cathy Schoen observed that, at Wildwood, “the addition/renovation option is a nice fit,” taking advantage of the flatter part of the property. “You don’t have to go into the hill, you have room for the wells, and it looks like you get daylight,” Schoen said. At Fort River, Schoen thought new construction was a stronger solution since it allowed for raising the building to mitigate high groundwater.
A community forum has been scheduled for May 5 to review school options with the public. A preferred solution is expected to be picked by the ESBC in June, which will include site selection (Fort River or Wildwood), the choice of addition/renovation vs all new construction, ground source or air source heat pumps for heating and cooling, and a decision of whether a 1&2-story, 2-story, or 3-story school would be built.
Geologically they seem quite similar, but I notice (1) space of the sites and (2) traffic around the sites, were not mentioned, which seems to me makes a significant difference in the two sites.
Space is self-evident — the Wildwood campus is much smaller than Fort River, for a lot more kids (and a lot more parking).
And traffic — I’m often at Wildwood in the morning waiting for numerous buses to head in / out the fairly small street intersection at Strong. And, I recently was on High Street in the afternoon, stuck waiting for bus after bus through this small residential street, heading to/from the middle school. It seems evident that a larger Wildwood will create many more buses in and out these very small neighborhood streets / intersections, with very little room for expansion of the roads. And the larger parking needs will take away playspace from an already small site.
You’re correct, Laura. There are many other differences between the two sites, including size and traffic.
At the next building committee meeting on May 6, there will be further discussion of the traffic flow on and off both sites. The traffic report (https://www.amherstma.gov/DocumentCenter/View/60474/Fort-River–Wildwood-Traffic-Existing-Conditions-Report) recommended that if Wildwood were selected as the site, they look at creating a second driveway to mitigate vehicle queuing. The design team has made comments indicating this might not be viable due to the cost and so they are exploring the viability of “a very small roundabout” at the current Wildwood entrance and whether that might help with traffic flow. There may also be a need for improvements at the intersection with East Pleasant Street and Strong Street where backups were noted in the report and would likely be exacerbated by the larger school population. Currently, Wildwood is typically served by seven buses and five vans. Once another 225 kids are added, there will be far more buses and vans, creating a need for a longer drop-off zone and longer driveways.
The green space per student at each site post-construction has not yet been shared. I imagine there will be a significant difference there as Fort River has literally acres of flat, green space while Wildwood has relatively little flat space that won’t be built on or paved over.
Fort River School seems the logical choice given it has so many more acres of land-flat land. This means more places for more kids to run and play, room to park cars and the town owns an adjoining field so that could be used . The Fort River itself can be used to learn about river ecology. Geothermal heat will be easier and cheaper at Fort River School. The school also is on a bus line for guardians without cars and has a separate entrance and exit for vehicle traffic. So this seems an easy decision.
On a related front, I hope the school building committee favors re-use/ re-build to save resources and money and reduce carbon dioxide emissions. We need to walk our talk on the environment, finally.
too bad the sites were chosen. The Hatch Act forbids use of our wet lands for building and its been around since 1965. No supprises here. Even the contractors/land lords geta pass such as 70 U Drive seems to indicate. Where will we loose our aquifer next? Only those who plan with other priorities in mind know that answer.
Chad Fuller
Related to Laura Quilter’s comments above, a new Traffic Study was published last week and can be found here:
https://www.amherstma.gov/DocumentCenter/View/61499/22_0505_Draft-Traffic-Study
At Fort River, to mitigate the impact of increased traffic, the traffic engineers have suggested widening a section of South East Street between College and Main to allow for a longer left turn lane heading northbound. This mitigation would likely be needed regardless of which site is chosen for the school since almost half of Fort River students live south/southeast of the school and would still travel up South East Street through the intersections at College and Main if the new school were at Wildwood, unless of course Amherst Woods or other southeastern neighborhoods are redistricted to Crocker Farm. They also suggest allowing southbound traffic leaving the school to exit via the southern driveway.
At Wildwood, to slow down traffic on Strong Street they are exploring a roundabout at the entrance, and improvements at the intersection of Strong and East Pleasant Street including adding turn lanes at one or multiple intersections approaches and signalization of the intersection. They have all but ruled out the viability of a second driveway at Wildwood (to help with traffic flow and queueing on the site) because of the steep hill it would have to descend from Strong Street (would be prohibitively expensive) and the inadequacy of sight distance due to the vertical and horizontal curvature when looking to the east from the site.