November 10, 2025 Planning Board Special Meeting - WEHI Transcript

01/05/2026 03:19:18 PM Page 29 to 32 of 112 8 of 28 sheets 29 One question regarding the slope disability1 analysis. You mentioned that at times that heavy rain2 falls somethings accounted for in the analysis. How,3 how does that change the analysis or how do you go4 about --5 THE WITNESS: What -- the way the6 groundwater works, if you, you assume what's called a7 phreatic surface, that's where most atmospheric pressure8 occurs and down below, then below that you start to9 develop pressures that would get into the rock joints,10 or that they lower the frictional resistance of the11 soil. In other words, friction is kind of weight times12 sandpaper or whichever. If I reduce the amount of13 contact pressure on a given surface, I do that by making14 the soil buoyant. And in some cases you can build up15 excess pressures. For instance, if that particular16 location is connected by a rock joint the groundwater17 level which is 60 feet higher, you're going to build up18 a very high pressure there that could, it could even19 liquify the soil if that occurred. We don't know that20 that those joints exist, but it's always a potential to21 be considered. There's nothing yet indicated in the22 record that they exist. The, when and if the building23 is excavated they should have experts to characterize24 the bedrock that's exposed in the slopes and to check25 30 for jointing systems that could lead to a problem and1 grout them or do something to mitigate the, the2 possibility that water generated by the infiltration3 system or otherwise would create one of those4 situations.5 MS. KAPFERER: Thank you.6 And one question about the soil mottling.7 How is it determined or how does one determine when that8 is present? You know, when you're out in the field.9 THE WITNESS: I think it's explained in the10 Princeton Hydro report pretty much in detail, but you11 get blotches on the, when you look at the soil on the12 sides, you dig with a -- where the backhoe digs in and13 leaves a smooth surface a lot times on the edge and you14 could see patches of gray in certain areas concentrated15 within the range of a couple of feet and the people who16 are sent out to do these things frequently visit17 training courses that are given to identify the cut and18 there's a pretty rigorous method for describing the soil19 colors. The Langan borings -- the Langan test pits just20 used what are

tly visit17 training courses that are given to identify the cut and18 there's a pretty rigorous method for describing the soil19 colors. The Langan borings -- the Langan test pits just20 used what are more, much less rigorous engineering cut21 color. In other words, brown, gray and did not notice22 any particular secretions or blotches of materials in23 the test pits. So, and I think in the rebuttal report24 they contended that they were not noted and that they25 31 were not noted because there's not a groundwater1 condition on the slope.2 MS. KAPFERER: Does the DEP require a3 certain analysis or, I know there was a color chart that4 was referenced?5 THE WITNESS: Yeah, the Munsell Color Chart.6 MS. KAPFERER: Is that what the DEP requires7 when analyzing a soil boring or mottling?8 THE WITNESS: That's a standard that they9 apply and it's mostly, I think DEP is for the, for the10 mitigation of -- for the best management practices, you11 know, in order to assure that ground is, infiltration of12 groundwater models the current condition before13 development. But they reference that system in their14 standards.15 MS. KAPFERER: Okay. Thank you so much.16 CHAIRMAN BAGOFF: Vice Chairman Guarino, do17 you have any questions for Mr. Kleinberg on his18 testimony?19 VICE CHAIRMAN GUARINO: Thank you, Mr.20 Chairman.21 So thank you for being here tonight and your22 explanation. Is there anything out there, anything that23 you haven't received, anything that warrants test pits,24 site evaluations, is there any information that you do25 32 not have that would have a significant impact in your1 evaluation?2 THE WITNESS: Langan indicates that they are3 going to be providing analysis for the, assuming that4 this groundwater level rises near the surface and they5 say that's forthcoming. So we should have that to6 review and they should provide an analysis as to whether7 the installation of an infiltration system at the top of8 the slope assess the impact of those, of those systems9 on the potential for influencing the stability of the10 slope.11 VICE CHAIRMAN GUARINO: Thank you.12 CHAIRMAN BAGOFF: Mr. Alper, do you have any13 questions for Mr. Kleinberg on his testimony?14 MR. ALPER: I do.15 In your recommendation Mr. Kleinberg, Page16 19, you're number 6 is that the applicants engineer17 should propose stability evaluations and conservative18 the service reflect the response

PER: I do.15 In your recommendation Mr. Kleinberg, Page16 19, you're number 6 is that the applicants engineer17 should propose stability evaluations and conservative18 the service reflect the response of groundwater and19 heavy storm rainfall. So is that something you need to20 see?21 THE WITNESS: That's what I -- and Langan22 indicates that they have done that. We just haven't23 seen the actual output of the results and they say24 that's forthcoming.25