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Coppell Greens-CS150107Date: January 7, 2015 Dear Ms. Perriton, In response to your e-mail, we believe that the French drain which was installed is unfortunately not satisfactory and has not adequately resolved the drainage problem behind 851 and 854 Applecross Court. I walked around your development and the north end of our property a few days ago and I would like to address a number of issues. Flooding Behind 851 & 854 Applecross Court Prior to the development of your property, there was a swale which ran along the south boundary from Denton Tap and fed water into the large ravine on your property and down our spillway. Now that the detention pond and the retaining wall on the south side of your lots 38 to 42wall has been built, water is supposed to sheet drain off those lots northward to the street, into curb inlets and then be collected in the detention pond. Some portion of the water, however, is flowing to the south over the retaining wall and into the area behind 851 to 854 Applecross Court. The above photos were taken two days after there was rain and there is still standing water. I would suggest that the way to resolve the flooding problem would be to construct a swale and berm as indicated below. The berm would prevent water from flowing into 854 Applecross Court and then under the fence onto 851 Applecross Court as it now does. On your preliminary grading plans issued on 7/8/13, lots 38 to 42 were changed to type D lots draining north to the street. There was a drainage line shown on the south side of those lots which drained water to the detention pond. When those plans were revised, however, on 9/4/13, that drainage line was eliminated. Now during a rain, water sheet drains south to the edge of the wall, ponds and then flows down it. You should also note that the lateral wall shown in the photo below has cracks which I assume are from the retaining wall settling which is made worse by the water pressure against it and the fact that none of the weep holes at the bottom of the south wall appear to be draining. I would suggest that you install a French drain or v-ditch along the north edge of the wall to collect the water similar to the drainage line which was eliminated. Runoff Into The Greenbelt Between 850 Applecross Court and 845 Fallkirk Court When we met initially with Gehan Homes to discuss the development of the site, we were told that the east end of your new retaining wall along your south boundary would tie into our retaining wall in the greenbelt between 850 Applecross Court and 845 Fallkirk Court. It was a surprise to see that you terminated the east end of your wall with a turn north at the manhole rather than connecting the wall into our wall. Now water is flowing off the southeast portion of your property onto ours. The silt fence is not in place and is in violation of the SWPPP. Crack in Wall Ponding water • Why was the wall not connected into ours? • Why was there no inlet installed and connected to the manhole to tranport water in that area to your retention pond rather than down into our greenbelt? • What actions are you going to take to rectify this? West Detention Pond While we appreciate the effort that was made to grade the greenbelt behind 832 to 844 Kilbridge to prevent ponding from the increased flow of water coming from your site, there still is ponding water as shown in the photo below behind 856 Kilbridge. Additional grading work needs to be done to form a swale so that water coming from your west detention pond does not pool and become stagnant. We have had mosquitos with West Nile virus found in our neighborhood by the City of Coppell and it poses a significant health hazard. We need to prevent areas like this with standing water in the future. Also, I question why rip-rap was placed only in the notched portion of the detention pond wall while the entire south side of the wall, which has the same top of wall elevation of 530.0, has no rip-rap. Remove course of stone to creat e weir Rather than placing rip-rap along the south portion of the wall which is on our property, I would suggest that you simply remove a portion of the top course of stone in the notch wall as indicated above to create a weir. The water would then spill across the rip-rap in the notch area and along the swale which you would grade. This would prevent pooling of water and eliminate the problem. This correspondence has been reviewed by the Coppell Greens HOA Board as well as our property manager. We would be happy to discuss this with you further at your earliest convenience. Sincerely, Philip LaBerge Coppell Greens HOA Rip -ra p in this area but not along south wall of pond.