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Wellington Place-CS 951116 Mort:son Hydrology/Eng eering, Inc. 210 Arnold · Arlington, Texas 76010 · Metro (817) 461-0321 November 16, 1995 Monsignor Broderick St. Martin de Porrea, Inc. 3725 Blackburn 4th Floor -~'~ .... Dallas, Texas 75219 Summary of Recommendations to Reduce Flooding at the Wellington Place Apartments, Coppell Texas - Dear Monsignor Broderick: As you know, we are in the process of completing a study to identify a feasible approach to reduce the flooding at the Wellington Place Apartments. Mr. Joe Dingman asked that we provide a short summary of the results of our study. The study report will be provided after we have met with Mr. Ken Griffin of the City of Coppell staff. The following is a short summary of our findings thus far. Summary of Approaches to Reduce Flooding at the Wellington Place Apartments 1. Improve the existing wall along the north side of the apartments. This includes the following: a. Obtain structural verification that the wall will withstand up to three feet of stormwater or provide details of needed structural improvements. b. Waterproof a portion of the wall by coating it with hydraulic mortar or other coating and fill in the open portion at the bottom of the wall. 2. The property to the south of the apartments is to be filled as part of a proposed development. This will block the floodplain from that portion. Page -2- 3. An interior pump system is to be constructed that includes~ a. Submersible waste/storm water pump capable of pumping 1 cubic foot per second. b. Electrical wiring for automatic pump operation during stormwater conditions. c. Pump housing including an in-ground six foot diameter reinforced concrete pipe. Modify the area at the west end entrance of the apartment complex to ...~\~-'~ ~_' . reduce stormwater flow coming from MacArthur Blvd. This modification would be an earthen berm along the front of the complex and a speed bump across the entrance drive. 5. A proposed development to the south has planned a channel to carry the stormwater overflow from south of our project. This channel must be extended north and along the east side of the apartment complex. This will require purchase of additional property and grading of a channel. 6. Purchase an additional.area on the east end of the apartment complex and construct a detention area. This area would generally be slightly less than one acre. The detention area would be a graselined area with a berm along the sides at an elevation higher than the 100 year floodplain. The above improvements would reduce flooding so that there would be no damage to the apartments. The construction cost of these improvements is very difficult to determine at this preliminary stage. We believe it would be roughly as shown belows 1. Wall improvement (no structural) $12,000.00 2. South property fill by adjacent developer No cost 3. Pump 7,500.00 4. Entrance modification 3,000.00 5. Channel modification (Does not include purchase price of the property) 10,000.00 6. Detention Area (does not include purchase price of the property) 13,000.00 Total $45,500.00 In addition, there would be engineering and surveying fees for a final study of these improvements. Page -3- We also recommend a survey of the site to determine if there are any low areas that may need special consideration. The cost for these unknown improvements are not included in this summary. Mr. Lew Lebowitz at 214-369-9362 may be contacted to determine the cost of purchasing the property east of the apartment. We can provide details of the size requirements which could be adjusted to keep the purchase at a minimum. We will contact Mr. Ken Griffin today to arrange a meeting to make sure the c£ty has no problems with these concepts. Sincerely, MORR?SON HYDROLOGY/ENGINEERING, INC. Ronald W. ~orr~on, ~. ~. Sen~or Hydrologist