December 3, 2025 Regular Meeting - WEHI Transcript

01/05/2026 02:58:16 PM Page 5 to 8 of 68 2 of 17 sheets 5 recommend that they include an elevated water surface1 elevation in their stability analyses. It's my2 understanding that Langan had included a case with an3 elevated water level in their original submittal but4 they didn't include the output drawings showing that5 summary of the calculations and we asked them to send6 them to us. They sent them to us about a week ago. I7 got home from vacation on Monday and took a look at the8 information and we noted that the water level that -- we9 felt that the water level they assumed wasn't high10 enough and that we recommended that they consider a11 water level at the surface with seepage parallel to the12 slope. This is an extreme condition, it's not certain13 that this could ever occur and I believe it's Langan's14 position that the condition cannot occur. But it's a15 worst case scenario and it's a, what if, question.16 There's a rather simple calculation that can17 be done to determine what the slope stability for a18 shallow slope failure under a condition with groundwater19 is flowing the groundwater level is at the top of the20 slope and that the seepage is parallel to the slope, so21 there are hydraulic, additional hydraulic measures which22 lead to a reduced stability. Using, we gave them an23 example of some simplistic calculations that showed that24 if a condition could develop and would develop that kind25 6 of flow that the stability would become marginal for1 shallow and localized slope failures. That's assuming2 the soil properties that were assumed for the, by both3 engineering firms, the opposers engineer and the4 applicants engineer, that assumes there is no cohesion5 in the soil, kind of sticky property that would be in6 certain types of soils compared to a plain sand. All7 the analyses done to date have been done for plain sand8 materials over lining the bedrock and additional type of9 cohesion and Langan's discussion, back and forth10 discussion on what we were recommending, Langan11 indicated, and we agree, that there are procedures for12 taking credit for the root action of the vegetation on13 the slope. And that, and that it can be shown to apply14 a significant amount of additional resistance equivalent15 to soil cohesion. And so we recommended to the, I think16 it was to Mark Seel, Langan's engineer who worked on17 the, their stability

apply14 a significant amount of additional resistance equivalent15 to soil cohesion. And so we recommended to the, I think16 it was to Mark Seel, Langan's engineer who worked on17 the, their stability study, that they do the engineering18 analyses showing what the additional credit could be19 taken for the vegetation and make a formal submittal to20 confirm that.21 In addition, the other outstanding22 item that we had was that we noted that the stormwater,23 the best management practice is a stormwater management24 system will be inducing the groundwater infiltration at25 7 the building, on the west side of the building, which is1 further away from the ridge line, but that would, we2 recommended that the applicants engineer confirm that3 the stormwater infiltration would not introduce or under4 sever rainfall system situations rather that that would5 not introduce any flow towards the slope that would6 impact the stability. And so we left them with those7 two recommendations in a conversation yesterday on the8 phone.9 MR. AFRAN: Is there any10 writing that reflects that discussion?11 THE WITNESS: I have my comments on e-mails.12 I can leave that with the board.13 MR. AFRAN: Well, I am a little concerned of14 the idea if you're producing a report outlining what15 needs to be done and now we are told that you made a16 request and phone call and none of us were privy. So we17 need to have some written record to show what was18 discussed and what was agreed with that. I need to know19 that. I can't cross-examine without seeing that20 material. Do we have that here?21 THE WITNESS: Yes.22 MR. AFRAN: Okay. Well, let's perhaps we23 break and take a look at that. I want know if it24 exists.25 8 THE WITNESS: It exists. It's here.1 MR. AFRAN: I can take it now?2 THE WITNESS: Sure.3 MR. AFRAN: Thank you.4 MS. McGOVERN: Okay.5 MR. KLEIN: Wait a minute.6 MR. AFRAN: Is there a problem?7 MS. McGOVERN: I would like to see it8 because I wasn't a part of it.9 MR. AFRAN: Well, yeah. Here's the thing,10 it's kind of long.11 MS. McGOVERN: I think what we need to do is12 make a copy and mark it for identification. So is there13 a copy machine close by?14 You can write the number on it and mark it.15 MR. AFRAN: Mr. Kleinberg, other than what16 you gave us, is there any other writing that references17 that discussion?18 THE WITNESS: No.19 MR. AFRAN: You also mentioned that

mber on it and mark it.15 MR. AFRAN: Mr. Kleinberg, other than what16 you gave us, is there any other writing that references17 that discussion?18 THE WITNESS: No.19 MR. AFRAN: You also mentioned that there20 was a discussion with Mark Seel dealing with an21 engineering analyses for the additional credit for the22 vegetation, is that discussion referenced in that23 e-mail?24 THE WITNESS: Yes, it is.25