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PC Minutes 2-7-06 CHANHASSEN PLANNING COMMISSION REGULAR MEETING FEBRUARY 7, 2006 Acting Chair McDonald called the meeting to order at 7:00 p.m. MEMBERS PRESENT: Jerry McDonald, Kurt Papke, Deborah Zorn, Dan Keefe, Debbie Larson and Mark Undestad MEMBERS ABSENT: Uli Sacchet STAFF PRESENT: Bob Generous, Senior Planner; Sharmeen Al-Jaff, Senior Planner; and Alyson Fauske, Assistant City Engineer PUBLIC PRESENT FOR ALL ITEMS: Janet & Jerry Paulsen 7305 Laredo Drive PUBLIC HEARING: MINNETONKA MIDDLE SCHOOL WEST: REQUEST FOR AN INTERIM USE PERMIT TO PERMIT OVER 1,000 CUBIC YARDS OF GRADING ON PROPERTY ZONED OFFICE & INSTITUTIONAL DISTRICT LOCATED AT 6421 HAZELTINE BOULEVARD (HIGHWAY 41), PLANNING CASE NO. 06-03. Public Present: Name Address Dennis Clark 6651 Hazeltine Blvd. Bob Generous presented the staff report on this item. McDonald: Kurt, you want to go first? Papke: Are there going to be any issues, I mean kids, water, playing in the water? Any fencing? Any barrier? Any concerns? What’s the plan there? Generous: There’s nothing proposed as part of this development. Fencing generally we don’t put around storm water ponds. There’s over 3,000 in the community. We need to start setting that precedent to go on. This is on the back side of the school. It’s not a heavy use area for the school district. So and again this is intended to be a dry pond so there will only be water in storm events. Papke: In a storm event, how deep does it get? Planning Commission Meeting – February 7, 2006 Fauske: The plans indicate for a 100 year event 4.4 feet. Which is quite typically in your typical design for a pond in a development you will typically have between 3 and 10 feet all the time with another 3 feet of bounce on top of that. Zorn: Bob, is there any type of recommendation for timing of construction? Perhaps at the end of the school year that we can recommend to help alleviate children being near this area. Generous: That didn’t come up as part of our discussion. I wonder if the applicant might be able to answer that. Zorn: Okay. Mike Murphy: I’m Mike Murphy, Larson Engineering. I prepared the plans and I’m th representing the applicant tonight since he’s on vacation. It’s scheduled for June 15 when th school’s out through August 15. The construction on this project. Zorn: Thank you. Mike Murphy: Anything else? McDonald: No? The only question I have for staff is that you had placed in the report about there may be the need to take some of this fill and put it someplace else within the city of Chanhassen and you were unaware of what those plans were. Has that been resolved? Generous: No, and as part of any grading permit they would, if they’re going to export it to the location in the community, they need to notify us and we have to verify they have a grading permit for that site. If they’re taking it out of the city, then they just have to notify us as to the haul routes. McDonald: Okay, but at this point they have not made you aware of what their plans are? Generous: No, I’m not sure. They could know that details. McDonald: Okay. Then in that case we’ll ask the applicant to come forward and present their case. Mike Murphy: Well Bob mentioned, described it very well. Basically we’re adding a 3,400 cubic yard infiltration basin at the request basically of the Department of Transportation and the DNR. They’re requiring a maximum of 5 to 6 cubic feet per second runoff. We’ve met that requirement. It’s currently under review from the Department of Transportation. There’s a permit application for right-of-way from MnDot and also a drainage permit that they’re reviewing currently and the DNR has provided the school with a cease and desist order to remove the erosion across Dennis Clark’s driveway and that will be done in May. Before May th 30. McDonald: Any questions for the applicant? 2 Planning Commission Meeting – February 7, 2006 Keefe: I’ve got a quick question. In terms of the fill requirements, are you anticipating that you’ll be removing a lot and then back filling or how does, what is the process for this particular site? Mike Murphy: Well it’s entirely, almost entirely removal. It’s currently I believe 600 to 700 cubic yards on site from a previous project is how it was brought in, fill in. Which was a road is calculated at 600 and 700 cubic yards. Last year before we knew of this issue with MnDot so now it’s, they’re removing yet another 3,400 cubic yards to come up with this plan. Keefe: Okay. McDonald: Thank you very much. At this time I’ll open the meeting to the public. Anyone wishes to make comment, please come forward. State your name and address and we will hear your comments. Dennis Clark: I’m Dennis Clark and my property is south of, south of the, it sits on the bottom of the hill. It’s about 7 acres so the wash, the 600 or 700 yards that has washed that’s gone now into the pond has kind of been an issue so they’re, everyone’s doing their best to clean that up. It’s a pretty big canyon actually of what is washed. 700 yards of dirt would probably be as big a hole as this room and there’s also been some fairly mature trees that have come down in this. I would say maybe 8 that are 100 foot trees. Pretty big in diameter. They’re talking about reforesting that. I haven’t really seen the, any particular plan on that or what they’re trying to do. I’m sure they’re going to try to, or we’d like to see something replace. You’re not going to be able to put back 100 foot trees so I do got some concern on that. The amount of water that comes down in the spring, and where this started was from the reconstruction up on the top of the school when they re-graded and blacktopped all of that and there was some question then from the folks south where’s all this water going to go? We pretty reassured them that this was under control. I don’t understand what 5 to 6 cubic feet of water a second are, but this stuff is a river that’s coming off and the holding pond on the top, I don’t quite get it. It’s, you know I mean I’m sure the engineers have studied the water but I don’t know if they know how much water, what created this canyon now or what the existing shore was for years that was fined so there must have been enough, being able to be dispersed but then when they added all that blacktop on the top, that water I think surprised everybody, and this has really been going on for 2 years. And finally the trees started falling down and that’s when the alert was. So 3 questions are, even the trick of getting this stuff out of the pond is going to take more equipment and there’s a lot of mature trees all over this property that I’m thinking they’re going to get affected so I’m kind of concerned because that’s my berm to the highway, to the school. The frontage. I’ve got a pretty long driveway. 100 yards there probably. So I sit, and I don’t know, can we put the map up on how big that piece of property is. It’s kind of hidden so nobody knows, it was the only one on that pond. It’s been there 20 years. Okay so this, there’s actually two sections. That little sliver right up here is where the erosion is and that’s the forestation that’s taken out. It actually goes in and has a slot there but I’m just trying to make sure that it’s on record that we’re looking for some serious reforestation there. And I don’t know how they used to do the equivalent to that when they’re, I know when they’re cutting trees down it’s so many inches bigger. You know if you take, there’s probably some formula there. If you take a 24 inch tree 3 Planning Commission Meeting – February 7, 2006 you get 24, you know you might end up with 2 more trees or bigger pine trees. I believe there’s some formula there. I would like to see that applied in this case. And maybe that’s in the plan. I didn’t look at the plan. I’ve been out of town and. And then it’s the part that’s going also down to the pond so there’s the hill where the big canyon is where the trees are coming down, the power company’s probably got a little concern in there too because their big power poles, they’re now within 10 feet would you say. Have you been up there? 10 feet of the hole. That will shut down the whole west metro so I think they want to get on this thing. If those things, you know that’s that big power trunk line that goes through there. But that doesn’t show up on the map. So urgency, you’ve got spring water coming. I don’t know if there’s any contingencies. I think the original dirt was just even, we thought we’d probably patch it up and maybe we just had a sewer that was plugged but, so it’s back to these how big is this sewer. My concern is, I don’t understand the 4 foot water holding pond. When this water comes, it’s a river folks. It’s not just a trickle so I don’t know how big that thing is. If it’s a swimming pool? Two swimming pools? It doesn’t mean anything to me. I just question that and how fast. If you have two rain storms in a row or 3 in a row, this thing’s coming over and now when it comes over and breaks that dike, now you’ve got this whole western, or the whole southern slope which, this whole property line right here, that’s all hill. They don’t show the contours. See it back up here. That’s all, the school sits, I don’t know what the height of that hill is. 100 feet higher. So DNR got involved and they wanted this water to go north. What ever happened to that, I mean they wanted to divert this water north and everything naturally. That pond is a runoff holding pond and then that goes under the road, over to Minnewashta and my first discussion was why don’t we shoot it right under the road now into Minnewashta Park because that’s all swamp down there on the other side. And the other thing I’d like in consideration here, one more note and then I’m done, is Carver Park is going to start a project on the other side of the road and I think they’re going to make an egress into the park there for a dog park, and I don’t know what happened to that plan, if that’s going down, but this whole driveway area that’s going to have what, bulldozers or going down into this thing and pulling the silt out. You ain’t going to do it with shovels. They made a beach. 700 yards of dirt like this just went down onto that sand and it’s made a beach and you know I don’t know if there’s going to be more construction going on there but that whole spot out on the highway there is probably going to be coned up and you know I don’t know if there’s projects, you know just don’t know if they’re going to make that wider. Put a new culvert in. I don’t know the engineering part of this thing that’s coming down. That’s all a wash now. Everything’s, it’s even taken out my driveway underneath. So the school has come back in and has re-packed underneath my driveway to hold some of that dirt, and that will be gone in the spring. So there’s, you know just trying to say it’s, I don’t know what the dates are but spring is coming and water’s going to be flowing there pretty soon and it’s going to be another 500 cubic yards of dirt down in that pond. McDonald: Okay. Thank you very much. Does anyone else wish to come forward and make comment? Seeing no one else coming forward, I now close the public meeting and I bring it back up to the commissioners for discussion and review. Keefe: Yeah, I just have a question. Maybe, can you speak at all to any of you speak to the adjacent properties in terms of the water flow that the gentleman was speaking about. I mean is it, is the water really flowing? Is this going to slow down the water that goes onto that adjacent property or what can you tell us? 4 Planning Commission Meeting – February 7, 2006 Fauske: I can speak in generalities on the storm sewer pipe design shows that it will discharge into that basin and the intent of the basin is to slow the water down. Provide it an area where it can pond and then slowly outflow through the outlet pipe. They do have some drain tile showing at the bottom of the pond which will go into the pipe just to slowly bleed that water down the slope, so to decrease the discharge rate. I don’t have the pre and post conditions to be able to speak to how much they are reducing that. I think that’s something their engineer might be able to answer, but that’s the intent of the system is just to slow that water down and then pipe it down. I believe they have it piped it all the way down the slope there which we were glad to minimize the amount of water going down that slope because they’ll have to actually eliminate the water going down the slope for a 100 year event. Keefe: How about in terms of reforestation on the adjacent properties? Is that contemplated as a part of this project? Generous: There’s nothing shown in this plans. I wonder if the applicant may have more information on that. I know that’s a separate DNR thing. Mike Murphy: We met with the Carver County Soil and Water Conservation District to help to deal with the wetland restoration. They have told us, me personally that we could remove small trees. That that erosion would be replaced or it could be removed with a, like a mini-excavator and a skid loader and trucks. We work within the right-of-way. MnDot right-of-way so we’re working with them right now to find out what their requirements are for traffic control, you know what times of day, if it has to be at night or what not. As far as the I guess canyon in this, as we’re calling it today, we’re not planning to add any trees in there. Again a majority of it’s within MnDot right-of-way. It’s kind of their call. They’ve seen it. They’ve seen it for over a month now. We’re waiting, anxiously awaiting comments from them. If that’s part of their plan, we’ll definitely put that stuff in. I guess I’d like to comment also on the discharge rate. We are at, we currently have an 8 inch, or 18 inch PVC pipe leading into this area currently. It drains directly over about 3:1 slope. Very steep slope causing the erosion. We’re going to replace that with this infiltration basin and an 8 inch outlet. That’s all there is to this pond. The high water level, the difference between the high water level and emergency overflow for the pond would be over a foot. So in a 100 year storm it should never overflow. You mentioned back to back storm events. This isn’t designed for back to back 100 year storms. It needs infiltration time. Keefe: Just sound, as the Planning Commission, I mean is it typical that when we look at restoration of adjacent properties? Kurt you brought it in. I’m trying to. McDonald: I guess the thing I would have for staff is, what’s our input? If this is on MnDot right-of-way and it’s probably more their call than anything but what input do we have into that as far as getting it put back to the way it was? Generous: As he said, it will never be put back the way it is because of the age of the trees. We can make recommendations to MnDot however it is their jurisdiction and they can say they don’t want them in their right-of-way or they do. 5 Planning Commission Meeting – February 7, 2006 Papke: Just one other point you know from a Planning Commission perspective, the only thing we’re looking at tonight is the pond. Okay, that’s the only thing we have any say over at this point. McDonald: Right, and that’s all the plan addresses too. That’s why all this other stuff isn’t in there. Mark. Larson: Yeah, I’ve got one. Sorry. Dennis mentioned that the blacktop was put in what, 2 years ago? At the middle school. The blacktop that you mentioned. When they expanded the blacktop at the school. Generous: For parking on the north side. Larson: So is that what’s causing the problem? I mean we’ve had incredible high rain amounts this last, well last year anyway. I mean I’ve had water problems in my home personally that has never happened in 20 years so what I’m trying to determine is it because they added the additional hard surface area and it sounds to me like you know, is the hard surface area then going to drain towards this pond? It kind of looks that way from what I’m seeing but it’s a little difficult to read. Generous: Yeah, this is on the south side of the building so this isn’t picking up the parking lot. Larson: Oh it’s not? Generous: As a part of that project they put in a separate storm water pond north of the school. Larson: It’s little isn’t it? Generous: I don’t know. Larson: Well I don’t know, I was just, it’s really hard to read this. Generous: …yeah and this shows that southwest corner, the entire site so you have all the field to the east of it. Larson: So where is it draining from? To this pond. Generous: I assume it’s coming down to this pond it would be the south side of the building and down into the right-of-way it would be on the west side of the building. Mike Murphy: Yeah, we prepared a drainage area map indicating, just based upon the existing contours out there, what is all draining toward this area of the site and it’s quite a bit of impervious surface from the building and there’s a large parking lot. There’s a track up there… Larson: But he just said the parking lot’s not going to drain this way so that’s not going to be… 6 Planning Commission Meeting – February 7, 2006 Mike Murphy: Well there’s service drives around the building. There’s a parking lot on the side of the site draining to the west so it’s, I don’t have the numbers right in front of me but I had submit a drainage calculations and I believe it was somewhere between like 3 or 4 or 5 acres or something like that that drains to the southeast corner. Larson: That’s not up to me to call. Dennis Clark: If I can address the Chair one more time? There’s an issue with, that needs to be solved. McDonald: Well at this point the open meeting session has been closed. I think what I’m going to have to do is defer that. The opportunity was earlier to bring that up. As has been stated, the only real issue before us that we can look at is the pond itself. Anything else that would deal with that is probably beyond the scope of this particular meeting. So I apologize for that but that’s what we have to do. We’ve got quite a few things to get through today. Mark, you were skipped. Do you want to? Undestad: No. McDonald: Well I guess I really don’t have too much to add to all this. I think that staff you know does need to stay in touch as far as where all this is going to go. Any input we can provide to alleviate some of these other problems I think we should go ahead and do. Having said that, can I have a motion before the commission. Keefe: Yeah I’ll make a motion. Planning Commission recommends approval of Interim Use Permit #06-03 to permit grading of approximately 3,400 cubic yards for an infiltration basin and drainage swale, plans prepared by Larson Engineering of Minnesota dated December 19, 2005 subject to the following conditions, number 1 through 23. McDonald: Okay. Do I have a second? Zorn: I second. Keefe moved, Zorn seconded that the Planning Commission recommends approval of Interim Use Permit #06-03 to permit the grading of approximately 3,400 cubic yards for a infiltration basin and drainage swales, plans prepared by Larson Engineering of Minnesota, dated December 19, 2005 subject to the following conditions: 1.The applicant shall provide the City with a cash escrow or letter of credit in the amount of $5,600.00 to guarantee erosion control measures and site restoration and compliance with the interim use permit. 2.Verify the existing 24-inch culvert has sufficient capacity before replacing the private drive entrance. 7 Planning Commission Meeting – February 7, 2006 3.The applicant must provide a proposed haul route for review and approval. 4.If fill is coming from and/or going to another site in Chanhassen, a separate grading permit will be required for the other property. 5.All disturbed areas as a result of construction are required to be reseeded and mulched within two weeks of site grading. 6.An erosion control blanket must be installed on all sides around the infiltration basin. All disturbed areas as a result of construction are required to be sodded or reseeded and mulched within two weeks of site grading. 7.Submit a full size drainage area map. 8.Add City Detail Plates Nos. 3101, 3102, 3103, 5300, 5301 and 5302. 9.Show rock construction entrance per Detail Plate No. 5301. The applicant shall construct and maintain a rock construction access to the site. Access to the site shall be restricted to this access point only. 10.The applicant shall obtain and comply with all permit requirements of the Watershed District and MnDOT. 11.Revise the existing storm sewer flow direction in all plans to match. 12.The applicant shall supply the City with a mylar as-built survey prepared by a professional engineer upon completion of filling and/or excavation to verify the grading plan has been performed in compliance with the proposed plan. 13.A plumbing permit must be obtained before installing the storm sewer piping. 14.The applicant shall provide a cross section for the filtration area showing the elevation of the drain tile and the trenches, as well as a cross section of the trench and details of the material used. The drain tile trenches shall be lined with drainage fabric (4% to 6% open space) and filled with pea rock at a depth of at least 18 inches and 3 feet wide. The bottom of the entire filtration basin shall be backfilled with a mixture of 50% coarse clean sand, 25% compost, 25% loamy topsoil for a minimum depth of 6 inches (from approximately 1034.5 to 1035.0). The rest of the area shall be top-dressed with native topsoil. CB-1 shall be revised to be an open beehive inlet at an approximate elevation of 1037 for handling large storm event runoff if the calculations for rate control work out to avoid overwhelming the filtration area and having long periods (greater than 72 hours) of ponding. 15.Erosion control blanket/turf reinforcement mat (MnDOT Category 5) shall be used for restoration of the exposed slope from the emergency overflow to the ditch along Highway 41 within 7 days of final grade. The blanket shall be specified and a detail provided. Erosion 8 Planning Commission Meeting – February 7, 2006 control blanket shall be installed on any exposed soils south of the private drive within 24 hours of final grade. 16.A seed mix for shaded, wooded areas shall be specified in the plan, along with the proposed rate of application. A seed mix for the filtration area and slopes shall also be specified. 17.The rip rap at the flared-end section at the south end of the 24-inch pipe south of the private drive shall be replaced. 18.Runoff from the storm sewer system from the school shall be controlled during construction. The water shall be conveyed through a non-erosive means to the Highway 41 ditch through the job site. 19.Erosion control blanket category 2 or 3 shall be installed within the filtration area within 24 hours of connecting the 18-inch PVC to the basin. The blanket shall be applied following a seeding. Remaining exposed soils on site shall be mulched and seeded or sodded within 14 days of final grade. 20.The silt fence used shall be a City of Chanhassen type 1 silt fence; monofilament silt fence with metal T-posts, 6 foot maximum spacing and 3 plastic zip ties in the top 8 inches of the fabric. The silt fence specified for the filtration area shall be labeled as “Installed after drain tile installation.” 21.A rock construction exit pad shall be installed from the bituminous edge 40 to 50 feet long into the job site. 22.Street sweeping shall be completed within 24 hours should soil be tracked upon paved surfaces. 23.Catch basin inlet control shall be provided for the catch basins adjacent to the school building if tracking of soil becomes a problem on the paved surfaces.” All voted in favor and the motion carried unanimously with a vote of 6 to 0. PUBLIC HEARING: PINEHURST REPLAT:REQUEST FOR PRELIMINARY AND FINAL PLAT APPROVAL TO SUBDIVIDE APPROXIMATELY 28 ACRES WITH VARIANCES ON PROPERTY ZONED SINGLE-FAMILY RESIDENTIAL (RSF) DISTRICT; AND THE VACATION OF DRAINAGE AND UTILITY EASEMENTS LOCATED AT PINEHURST DRIVE AND GALPIN BOULEVARD. APPLICANT: LENNAR CORPORATION (LUNDGREN BROS. CONSTRUCTION, INC.) – PLANNING CASE NO. 06-07. Public Present: Name Address Troy Bader 2244 Lake Lucy Road 9