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

03/03/2025 06:36:47 AM Page 29 to 32 of 115 8 of 46 sheets 29 existing conditions. So in other words, the contour1 lines reflect where the water will move and Mr. Walsh2 has created the two drainage areas that he has discerned3 based on the contour lines on the site as they exist4 today.5 Is that correct?6 THE WITNESS: Yes.7 MAYOR McCARTNEY: Did he change anything?8 MR. AFRAN: He hasn't change any existing9 contour lines. Simply identified where on the document10 the two drainage areas exist.11 Correct. Let me, I think I -- so, no, let me12 A. explain. What they show on this map is the drainage13 area of the disturbed area. So what I did was I used14 the coloring to show what would feed the entire wetland.15 That's it. That's the difference.16 MR. KLEIN: Yours is existing, their's is17 proposed?18 THE WITNESS: This is existing.19 MR. AFRAN: I think I understand. What's20 happening is on the original version the drainage areas21 showed by the applicant was reflecting the area of22 disturbance and drainage from that area. Mr. Walsh has23 shown drainage areas more broadly as they exist on the24 site. So he's showed -- he's showing other drainage25 30 areas not just drainage from the area of proposed1 disturbance.2 Is that a fair summary or am I incorrect?3 Q. Yeah, that, I wanted to show you the original4 A. one, the original DA that they had here. They point5 out, they had this disturbed point. They're only6 concerned -- they show the drainage area in the7 disturbed area. I was showing what's in the entire8 wetland, that's why I had the color. That's why I used9 colorization.10 COUNCIL PERSON SCARPA: Is that because11 there's other wetlands to be affected, so he's showing12 all different --13 THE WITNESS: I want to show everything, not14 just what was disturbed.15 COUNCIL PERSON SCARPA: And how it would16 affect each other?17 THE WITNESS: Yeah, and how that interacts.18 Sorry for the confusion.19 MR. AFRAN: Let me note, I was attempting to20 answer the question but obviously Mr. Walsh's opinion is21 authoritative, not mine. So his description obviously22 governs. To the extent I differ, Mr. Walsh is correct.23 Now, the area on the left is about 32 acres and24 A. the area on right about 48.4 acres. Now, I'm going to25 31 show you one more figure for this.1 MR. AFRAN: What's on the screen now is a2 colorized version of DA-2 and Mr. Walsh will explain.3 All

4 A. the area on right about 48.4 acres. Now, I'm going to25 31 show you one more figure for this.1 MR. AFRAN: What's on the screen now is a2 colorized version of DA-2 and Mr. Walsh will explain.3 All right. Can you see here, now we're looking4 A. at a proposed drawing and what I did was I, once again,5 drew the drainage areas that would feed the wetlands and6 what is shown is how that would change. You can see how7 it's through the developed area, because those no longer8 contribute to wetlands over here, over here or down9 these areas, the flows being routed to basins at the10 bottom of the site. And what we wanted to show was that11 there was a reduction in the drainage area and the12 wetlands. On this side the drainage area was reduced by13 about 9 acres, a 20 percent reduction.14 You mean the left side, the darker green?15 Q. Left side, darker green. And on the right side,16 A. the lighter green, that was a reduction of 16 acres,17 which is a 33 percent reduction. Just wanted to point18 that out and there would be an impact to the wetlands.19 MS. MCGOVERN: Okay. This is another new20 exhibit. This is going to be O-9 and we'll have to get21 that one submitted.22 So it's colorized DA-2.23 All right. Next I would like to talk about time24 A. of concentration. Time of concentration is a bit of a25 32 technical term but a very important term. So time of1 concentration is the time it takes for a piece -- for2 water to go from say the highest point on the watershed3 down to the discharge point. It's the time -- and that4 time is very important. That time helps dictate the5 peak flow runoff, especially in existing conditions6 modeling. Once again, that's restraining. When we7 develop existing conditions we know what's flowing off8 the site in existing conditions and DEP will require you9 to meet reduction rates so you're not causing flooding10 further down stream.11 This is an old document, this is, this DA-1 from12 the report submitted by the applicant.13 So this is not a colorized version, this is the14 Q. original DA-1, is that correct?15 So the only difference is I put two scaled16 A. measurements on here just to show the difference, that I17 will get to in maybe ten minutes.18 MR. AFRAN: So since it's on the screen, Ms.19 McGovern, I think we probably should make it O-10, which20 is DA-1 with colorized red arrows. Would that be a fair21 description?22 MS.

ybe ten minutes.18 MR. AFRAN: So since it's on the screen, Ms.19 McGovern, I think we probably should make it O-10, which20 is DA-1 with colorized red arrows. Would that be a fair21 description?22 MS. MCGOVERN: Yeah. Just the red arrows?23 THE WITNESS: Just those are all I added and24 you'll see why in like maybe five minutes or something25