February 26, 2025, Planning Board Special Meeting Transcript - WEHI

03/03/2025 06:36:47 AM Page 101 to 104 of 115 26 of 46 sheets 101 and findings some of the design calculations, they were1 not passing that.2 THE PUBLIC: So they didn't pass 2021,3 forget about 2024?4 THE WITNESS: Yeah, no.5 THE PUBLIC: Okay.6 Can I ask you to go to, I don't know if it's7 9 or 10.8 THE WITNESS: Can you explain to me --9 THE PUBLIC: You were talking about time of10 concentration. You were talking about it. It's a map.11 THE WITNESS: It's here.12 THE PUBLIC: I guess what I was trying to13 understand is, you were talking about that they14 artificially increased the time of concentration?15 THE WITNESS: They decreased.16 THE PUBLIC: Decreased it. Okay.17 Tell me what that really -- I am trying to18 understand, get my head around this. If they decreased19 the time of concentration, you know, when they take all20 the trees down the water can rush and it won't look like21 a big deal, right? I'm just saying.22 THE WITNESS: That's -- I'm not saying like23 that could happened. But like, yeah, generally it's24 higher so then when they change the landscape where it's25 102 going to generate more runoff it's easier to come down.1 THE PUBLIC: So I'm just trying to get this2 straight. If you artificially reduce the time of3 concentration --4 THE WITNESS: Yes.5 THE PUBLIC: -- and you see the water rushing6 down a slope and now there's not even anything to slow7 the water down because the trees are gone, it's going to8 look like fast time of concentration. I'll say fast.9 The water rushes fast. And then in your proposed10 conditions it wouldn't be such a shock when there's no11 buildings and no trees. It will just be a little bit,12 maybe a little bit faster, but we're going to put basins13 in that will hold and contain some of that water?14 THE WITNESS: Yes.15 THE PUBLIC: And so was your final thing16 where you showed that table and you said their time --17 was that time of concentration --18 THE WITNESS: That was peak flow rates.19 THE PUBLIC: Okay.20 And they were, you said increased or21 decreased over and above what the, what the site started22 out as? I hope I'm not confusing you, I'm confused, so.23 THE WITNESS: I gave very technical24 testimony, I appreciate everyone's patience for that.25 103 THE PUBLIC: I don't know where --1 THE WITNESS: This is the table.2 THE PUBLIC: That was their table from their3 storm management report?4 THE WITNESS: Yeah.

eciate everyone's patience for that.25 103 THE PUBLIC: I don't know where --1 THE WITNESS: This is the table.2 THE PUBLIC: That was their table from their3 storm management report?4 THE WITNESS: Yeah. So what we're saying, I5 was talking about the two-year storm and 100-year storm.6 Where they did the 100-year storm they calculated a peak7 flow runoff of 83.8 THE PUBLIC: Is that 83 --9 THE WITNESS: It's cubic feet per second.10 THE PUBLIC: Thank you.11 THE WITNESS: It's a big area. We12 calculated the peak flow rate of 37 cubic feet per13 second, so a lot lower than this. And what's really14 interesting to note is there was that their proposed15 peak flow runoff rate was actually higher.16 THE PUBLIC: Higher than?17 THE WITNESS: It was higher than what was18 calculated as existing. So it was actually almost two19 to three feet per second.20 THE PUBLIC: So that when the changes occur21 on the site it wouldn't show as a change, it will just22 be like, oh, we're keeping everything -- well, they're23 saying they're improving?24 THE WITNESS: They're saying they're25 104 improving, but we're saying in reality you're actually1 going to see it get worse.2 THE PUBLIC: Okay. Thank you very much.3 CHAIRMAN BAGOFF: Any other members of the4 public have any questions for Mr. Walsh? Please come5 up.6 THE PUBLIC: Seth Weisleder.7 We are focusing a lot on flow rates coming8 down and where they go, but I think at the beginning of9 your testimony you were talking about the storage.10 Storing of the water and basins. So if I am correct11 from what I understood, the basins, because of more --12 well, higher flow rates I guess, depending on where they13 fill up, they're going to be filled up to almost14 capacity based on potential mottling issues and not15 having the correct table, so potentially what I think16 you're trying to say is that their basins need to be17 deeper or recalculated, is that correct?18 THE WITNESS: Yeah. I wouldn't say deeper,19 have to be wider because the problem was they were going20 to deep. They were running into seasonal high, so it21 was eating away their storage. So you have to make it22 shallower and wider. You can't go deeper, you have to23 go wider.24 THE PUBLIC: And in your opinion, based on25