January 29, 2025 Planning Board Special Meeting Transcript - WEHI

02/13/2025 11:25:53 AM Page 53 to 56 of 143 14 of 57 sheets 53 THE WITNESS: That is and also didn't1 represent the majority of the slope.2 THE PUBLIC: Okay.3 My question for you, do you have any4 experience having sort of done a postmortem, when5 there's been a collapse, like is that part of your6 expertise?7 THE WITNESS: Yes.8 THE PUBLIC: Okay.9 And is it usually the main part of the slope10 that is the thing that causes the precipitating of the11 collapse or is it the aberration points, as they break12 off they then fall down and then the whole thing gathers13 steam and causes, you know, an avalanche?14 THE WITNESS: Well, triggering events vary15 by their nature, often caused by water as the main16 triggering of most slides.17 THE PUBLIC: Okay.18 So what are causes of most rock slides and19 avalanches, those kinds of things?20 THE WITNESS: That's a major precipitation21 event, yes.22 THE PUBLIC: Okay.23 And you said you found a water table on one24 of your test points. Can you tell us which one and25 54 point at with a laser where you found the water?1 THE WITNESS: Could you scroll to the test2 pit logs. I believe it was TP-1 or TP-8.3 THE PUBLIC: Could you just show us TP-1 and4 TP-8 and then we can come back.5 THE WITNESS: TP --6 THE PUBLIC: They're both right there at the7 absolute top of the slope.8 THE WITNESS: Right.9 THE PUBLIC: Okay.10 So the one place that you found the water11 table is at the absolute top of the slope, is that12 correct?13 THE WITNESS: Well, we're going to -- I14 wouldn't say it was a water table. Might have been a15 wet sample.16 THE PUBLIC: Okay. A possible water table?17 THE WITNESS: I would say localized water.18 THE PUBLIC: Maybe a water table?19 THE WITNESS: If there was a water table it20 would be continuous throughout the borings and test pits21 and we did not see that.22 THE PUBLIC: Okay.23 Unless it, you know, flows somewhere into24 that unexplored 375 foot by 700 foot area that you did25 55 not do any testing, is that correct? Couldn't that be1 possible, that there was water in that area that you2 don't know about?3 THE WITNESS: If there's water there it4 could be water pockets of water.5 THE PUBLIC: I'm sorry, could you say that6 again, I can't hear you.7 THE WITNESS: If there's pockets of water,8 purged condition, they could be. So test pit 1 had9 water, that had water.10 THE PUBLIC: Test pit 1. Okay.11 And can we

u say that6 again, I can't hear you.7 THE WITNESS: If there's pockets of water,8 purged condition, they could be. So test pit 1 had9 water, that had water.10 THE PUBLIC: Test pit 1. Okay.11 And can we zoom in a little bit to test pit12 1. No, you got to go to the left. Okay.13 So test pit 1, which is right smack in the14 middle of Building D or top third really where line A15 is, correct?16 THE WITNESS: Test pit 1 shows some seeping17 water, decomposed rock, so it could be a part of a,18 could be part of water, it could be water got into the19 rock and it's seeping, it was trapped in the rock and it20 just seeped in.21 THE PUBLIC: Okay.22 What date was that sample taken?23 THE WITNESS: This was dated November 15.24 THE PUBLIC: November 15, is that correct?25 56 THE WITNESS: Correct.1 THE PUBLIC: Are you aware that it had2 rained, less rain in the history of New Jersey for two3 months almost immediately prior to that date?4 THE WITNESS: I'm aware of that.5 THE PUBLIC: Could that have any impact on6 where you found water or not?7 THE WITNESS: That is possible, yes.8 THE PUBLIC: So it could be possible given9 that you tested these things after we have had the10 largest, longest drought that this entire area has ever11 seen in -- are you confident that if we had a normal12 amount of rain you would have gotten exactly the same13 results?14 THE WITNESS: No, which is exactly why our15 analysis we did sensitivity on different water levels16 within the entire slope. We treated the entire slope as17 it was saturated.18 THE PUBLIC: You stated earlier that your19 analysis is not necessarily an algorithm, it is based on20 opinions, right?21 THE WITNESS: A stability analysis. A22 stability analysis is done using a computer program.23 THE PUBLIC: I'm sorry.24 THE WITNESS: Using a computer program.25