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

11 of 46 sheets Page 41 to 44 of 115 03/03/2025 06:36:47 AM 41 that the peak flow runoff rate was 7.52, I'm going to go1 -- one second, I'm going to go to the report the2 applicant submitted.3 What was that figure you just said?4 Q. 7.52.5 A. All right. We're looking at Page 11 of the6 applicants stormwater drainage report, it summarizes the7 discharge rates they calculate for the proposed and8 existing conditions and I just want to compare them to9 our findings.10 So the existing, the two-year storm they have the11 existing flow rate of 17.5. Now, we calculated it as12 7.52, which is 10.2 feet per second more than what we13 have. So, again, this demonstrates how much higher it14 is.15 Now, if you're looking at this same table, it's16 stormwater, that means the storm size. This EX is17 existing. PER is permitted. So remember, I discussed18 the two-year storm, you have to reduce peek flow by 5019 percent. And then for the ten-year storm you have to20 reduce it by 25 percent. 100-year storm you have to21 reduce it by 20 percent, that's what's permitted. It's22 taking the existing flow they calculated and shows what23 they're allowed to permit.24 And this is shown from the applicants Page 11?25 Q. 42 This is applicants Page 11, yes.1 A. All right. Now, the T, the total, this is the2 last column. It totals all the other flows in this to3 give you the total flows. This is the target flow they4 need to meet. So they show the peak flow rate for a5 two-year storm is 7.24. Now, they meet it under their6 terms but if you take, remember we calculated the7 existing two-year storm as 7.5. You have to have that,8 which is about 3.76. So right now their peak flow is9 twice what it should be. So once again, they need to go10 back, look at their basins, look at their models, make11 everything bigger to hold more water back because12 they're discharging to much water right now. And I want13 to point out that on top -- this is on top of some of14 the other things we found where some of the basins are15 getting impacted by mounding, they're not going to hold16 as much and they're also impacted by the seasonal high17 water table. So we already know from earlier18 discussions that these peak, the peak flow rates that19 they're giving are artificially low and now we know20 that, you know, their bar is to high. Their bar needs21 to be lower. The sites going to generate more

that these peak, the peak flow rates that19 they're giving are artificially low and now we know20 that, you know, their bar is to high. Their bar needs21 to be lower. The sites going to generate more runoff22 than we think it is.23 So I also want to go through the 100-year storm24 as well for one more point.25 43 So their peak flow runoff rate for the existing1 condition is 83.4. We calculated it at 37.6. The point2 I'm trying to point out here is for the 100-year storm3 what they're predicting their flow rate will be is4 38.99. That's what their, after they build the entire5 development that's going to come out.6 That's what they said?7 Q. That's what they said. That's higher than what8 A. we're calculating right now. So that means in the9 100-year storm this sites going to generate more runoff10 than is does now today, which definitely exacerbates any11 flooding problem they're having downstream. Because12 existing conditions based on our measurements are 37.713 and they're at 38.99. I know these are a lot of14 numbers, I do appreciate your patience with it all.15 All right. I'm going to go back to one thing we16 want to bring up about POA-2. We're still in the17 stormwater drainage report that the applicant provided,18 this is DA-2. So POA-2 is right here. This is the19 final point of analysis. It's the point where all the20 water leaves the site. It's the point of analysis for21 the stormwater analysis to make sure you're not22 discharging more water. What's strange about this is23 that that's not where all the water goes. The water has24 two discharges locations. It comes from basin 2 and25 44 discharges at Kuzik Street and it also comes from basin1 7 and it goes to Warner Street. But for some reason2 this report treats them as two -- as not two distinct3 locations but as one. They're simply combined. But4 it's ignoring the flow from Kuzik, what the flow from5 Kuzik would be. What you're supposed to do is you're6 supposed to analyze both points so you don't have a7 situation where you're discharging more water coming8 into the one stream as opposed to other. For example,9 we don't really know how the flow is diverted based on10 the land development.11 Now, the drainage area that normally goes to12 Kuzik is much larger and they need to have to design to13 take that into effect or is it larger over here. You14 lose that in the detail.15 I'm going to

Now, the drainage area that normally goes to12 Kuzik is much larger and they need to have to design to13 take that into effect or is it larger over here. You14 lose that in the detail.15 I'm going to scroll to DA-1 again.16 Is it your testimony that we have a single figure17 Q. of discharge from the detention basin as for both18 instead of separate figures for each?19 Yes, the model treats those discharges as20 A. combined when they don't combine, they're two distinct21 flow rates. I would imagine what should happen is this22 larger drainage area should be split into two different23 drainage areas so these individual points can be24 analyzed individually. So they can be certain that the25