November 10, 2025 Planning Board Special Meeting - WEHI Transcript

01/05/2026 03:19:18 PM Page 13 to 16 of 112 4 of 28 sheets 13 evaluate the potential for the infiltration at that1 particular location to be detrimental to the stability2 of the eastern, the eastern slope.3 There was a good deal of discussion in the4 reports as to the impact of the construction on the5 stability. In other words, everything that was included6 in the -- well, no, I have to correct myself. There7 were factors at least for the bedrock where they have8 disturbance factors, where you're supposed to assume a9 certain disturbance influence, let's say if blasting is10 required, that that would change the character of the11 bedrock, the joint might introduce more fractures and12 create a different situation that was included in the13 analysis.14 So there are two affects, there's the affect of15 the construction for the building which involves16 excavations of up to 23 feet and removal of bedrock to17 that depth. And then there's the, the stormwater18 infiltration. These are affects that should be19 evaluated.20 We included at the conclusion of the report some,21 that if the application is approved to move forward that22 any approval should include a number of provisions that23 should be made to ensure that the stability of the24 slopes are monitored during the construction and we made25 14 specific recommendations. I can go through each of1 them.2 CHAIRMAN BAGOFF: Go right ahead.3 The, the clearing of the site should be4 A. controlled and maintained within the limits that are5 indicated on the site plan and should not be done6 carelessly so that it impacts the, the wooded area that7 is required to be maintained on the entire east slope.8 That there's no effects on that.9 There should be requirements for long-term10 maintenance of the health of the wooded area on the11 slope. It's our understanding there's a mandated12 requirement to maintain the woods on the sloping,13 sloping, on the eastern slope and even long after14 development we have, where I live we have a number of15 species that are endangered now by parasites and that16 sort of thing. So there should be some provision for17 maintenance of the forest.18 The Soil Erosion and Sediment Control Plan should19 provide specific details for protection of the ridge and20 slope. That's, in particular discharge of the watering21 from the excavation should be -- should not be, not be22 discharged over

an should19 provide specific details for protection of the ridge and20 slope. That's, in particular discharge of the watering21 from the excavation should be -- should not be, not be22 discharged over the slope and should be discharged with23 all the requirements that are ordinarily included in a24 Soil Erosion and Sediment Control Plan.25 15 Surcharges resulting from the excavation. In1 other words, piles of earth. Very heavy equipment2 operating on the slope, they should not operate3 immediately on the slope to the east of where the4 building is situated on the slope side of the site.5 There should be provisions to keep all equipment and6 stock piles away from the top of the slope.7 What we ordinarily do when we're specifying8 projects for capital improvement plans for towns, we9 require that the, before any excavation begins that the,10 that the contractor provide an excavation and dewatering11 work plan. That, describing in detail the methods that12 they are going to employ, what the limits are and they13 should be reviewed, usually we require that to be done14 by an engineer retained by the earthwork contractor and15 this engineer would look at criteria for blasting in16 particular and heavy rock excavation.17 We recommend, there's going to be excavation18 between, I guess 10 or 12 feet to about 25 feet in the19 Building D area. The excavation, ordinarily if there is20 not, if there is not a need to protect structures21 alongside the excavation the developer will -- I mean22 the contractor would cut the slope back so it falls23 back, but if they do that in this particular case on the24 eastern side of the building that would disturb the rock25 16 on the, at the top of slope and that shouldn't be1 permitted. Support of excavation systems that might2 even include rock bolting or tieback systems should be3 employed for excavation for the building because of its4 proximity to the top of the slope. And as we had5 mentioned they shouldn't allow, in other words, if there6 are layover times and there's rainfall and water7 collection at the bottom of the excavation that would8 infiltrate, could infiltrate into the bedrock and reduce9 -- and have stability impacts on the lower slopes. So10 the excavation has to be dewatered at all times.11 We recommend, because there are concerns from the12 residents that, that, there would be slope movement, so13 we recommend

on the lower slopes. So10 the excavation has to be dewatered at all times.11 We recommend, because there are concerns from the12 residents that, that, there would be slope movement, so13 we recommend that the, that the monitoring program14 include the installation of what's called, slope15 indicators. These are tools that will, that if the16 slope moves the tubes go through a curvature and you17 could tell if the slope, if and when the slope is18 beginning to move or it has moved and it would be a19 benefit, I think, to the applicant if he has a long-term20 record during the construction as to whether there is or21 never was any slope movement. It would be to his22 benefit to consider doing that.23 We think that groundwater monitoring wells should24 be installed because it's very difficult to determine25