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SC-Lee E2-CS 901016 ALLEN PROPERTY CORPORATION 12770 COlT ROAD · SUITE 121S · DALLAS, TEXAS 752~1 Telephone 214-233-$771 / Fax 214-233-$881 October 16, M~. Buddy Echols Mr. Joe Fitch S~dnte~nt ~ Chu~ of Chr~t ~ lSD ~ ~uth ~11 Rd. P.O. ~x ~ ~11, Texas 75019 ~, Tex~ 75019 Re: Drainage Plan - Properly North of Sandy Lake and West of Samuel Blvd. Genlbmen: This letter is for the purpose of confirming our conceptual approval of a method to partioipate in resolving, in a co-operative effort as affected property owners, a currently existing drainage problem in the City of Coppell, Texas, which is occuring in the southwest comer of the Meadow Ridge Townhome Development. This problem is occurring downstream from our respective properties. Your execution of this letter is being requested in order to 1.) facilitate lhe completion of the platting of the property herein referred to as the Church Tract as well as other plat requests forth coming from what is herein referred to as the Corner Tract, and 2.) to evidence our agreement to pursue the solution based on the preliminary Drainage Plan attached, so that the final engineering for the facilities envisioned cain be authorized to be completed. The engineering solution to this problem was preliminarily endorsed, subject to review of final engineering, by the city staff of Coppell in a meeting on September 10,1990. The city staff attending the meeting were Gary Sleb, Director of Planning, Steve Goram, Director of Public Works, and Shohre Danashmand, acting City Engineer. THE PROBLEM The Meadow Ridge Townhome project is located on the west side of Samuel and can be Identified on the location Inset map on the attached Drainage Plan. It was constructed in the mid 80's and has been mmpleted for some time. As part of the Meadow Ridge development, a drainage Inlet (the "Exisltng Inlet") was construcled in the southwest corner of the development which conveys surface runoff into an underground 60" slorm drainage system. These facilitlas have been constructed and dedicated to the City of Coppell. Richard E. Lee elementary school (the "School Tract") lies adjacent to the south side of Meadow Ridge, being the next properly upstream Irom the Meadow Ridge development. Surface drainage water currently sheet flows across the School Tract, following the relatively rial natural drainage course into the Existing Inlet. Currently no storm drainage system is constructed across the School Tract. Sandy Lake Corners Joint Venture ('SLCJV") and the Coppall Church of Christ respectively own 9.2 acres (the 'Corner Tract') and 1.57 acres (the" Church Tract') at the northwest comer of Samuels and Sandy Lake on the south side of the School Tract, being the next upstream properties adjacent Io the School Tract, and essentially the top of the overall dr,inage area. Currenlly surface drainage is sheet flowing generally to the northwest from these properties and across the School Tract and ultimately into the Existing Inlet. The City has advised all of the parties hereto that a drainage problem is occuring at the Existing Inlet; basically being a backup of water during Peak runoff Periods which is causing flooding within the Meadow Ridge development. SLCJV retained its civil engineer, Dan Dowdoy and Associates (the "Engineer") to study this problem to determine the cause and lo suggest an appropriate solution. Pursuant to the study conducted by the Engineer it was determined that the Existing Inlet is undersized, even for the current level of development and more so for a fully doveioPed runoff in the drainage area. The backup at the Existing Inlet occurs partly due to the drainage across the Comer Tract, the Church Tract and the School Tract, and also partly because of drainage that is reaching the Existing Inlet from a separate drainage area lo the west and southwest of these properties. This runoff is coming to the Existing Inlet across that certain propady known locally as the Austin Tract. The drainage coming across the Austin Tract is isolated by the natural topography into a different drainage pattern until it reaches the north boundary of the Austin Tract and the School Tract. THE SOLUTION The solution proposed by the Drainage Plan is designed to 1.) appropriately resolve the problem to the extent caused by storm runoff coming across the Corner Tract, the Church TrW mtcl the School TrW and 2.) to provide a facility Io which a future connection can be made to handle a portion of the separate drainage area from the southwest coming across the Austin Tract to the extent the City later deems it appropriate. Attached to this letter Is a copy of the preliminary drainage plan prepared by the Engineer (the "Drainage Plan"). The basic elements to the Drainage Plan which are conceptually approved by the parties to this letter are as follows: 1. Extension of the existing 60" storm pipe from the Meadow Ridge development into the northwest corner of Ihe School Tract, and construction at that location of a properly sized wye inlet (the "New Inlet") to accept the fully developed amount of storm water from the School Tract, the Church Tract and the Comer Tract. 2. Construction of a drainage swale running north and south across the west side of the School Tract, to direct the sheet flow from the School Tract and the upstream properties into the New Intel. The parties agree thai the drainage swale is an appropriate facility at this Ioca~n because it is across the western most side of the school playground area which is 425 feet in width. The swale will be construcled wilh a 10 to one side slope on the playground side to provide for easy maintenance of the swale and an gradual transition to the pl~/ground ama. 3. A permanent easement and dedication of Ihe New Inlet to the City for its maintenance puq3osas. 4. A drainage easement from the school district to the Corner Tract and the Church Tract along the location of the swale. The swale will be maintained by the school districl. -2- 5. Agreement of the Comer Tract and the Church Tract to co-ordinate an onsite drainage plan for. their respective properties designed to deliver storm drainage in an underground system from those properties to the south end of the swale. This co-ordinated plan will be reflected in the plaiting and engineering of the Comer Tract and the Church Tract. The parties hereto acknowledge that their approval of the Drainage Plan is at this time conceptuai in nature, and that they are by this letter expressing their willingness to cause or permit constru~ion of the various applicable elements in the Drainage Plan on their respective properties. The parties hereto acknowledge that their agreement to participate in the Drainage Plan is subject to 1.) approval of the final engineering design of the Drainage Plan by the city, and by each party to the extent the facilities are located on its property, and 2.) agreement among the parties es to how the cost of Implementing the Drainage Plan will be allocated among the parties. If this letter correctly reflects your position, please execute il in the space provided below and relum one copy to the undersigned. For convenience, this letter may be executed in multiple counterparts. Upon receipt of all signatures end whiten city endorsement of the Drainage Plan, SLCJV will cause a cesl estimate for the Drainage Plan lo be prepared by the Engineer and submitted lo the parties with suggesled allocation of the cost. Upon approval thereof, SLCJV will cause the final engineering to be prepared and submitted to the pm'ties for their approval. Please call if you have any questions. Yours very Iruly, Sandy lake Corne~ Joint Venture by its Manager, Allen Property Corporation Michael R. Allen, President APPFIOVED IN ~: Coppell Independent School District Buddy Echols, Superintendent Date hu~ of Christ -- Date Enclosure dr&inag®/be,j f/10.16.90 -3- DRA,,,,~GE COST COMPARISON - LEE ELEMEN, ~RY ..... .. i J 0CT I 81990 I COST OF ENCLOSED ST'ORM DRAINAGE SY81"EM - LEE ELEMENTARY FROM NORTH BOUNDARY OF FOOD UON SITE TO SoLrrH BOUNDARY OF MEADOWRIDGE TOWNHOMES ITEM QUANTITY UNIT TOTAL ENCLOSED STORM DRAINAC~ ~ PRICE COST LF 48" RCP 584.00 $70.00 $40,880.00 LS Connect to exiting 60' RCP 1.00 $1,500.00 $1,500.00 EA 4' x 4' Wye Inlet 1.00 $2,200.00 $2,200.00 EA Type B Headwa]l 1.00 $1,200.00 $1,200.00 CY Excavation for Swale 570.00 $1.50 $855.00 SY Hydromulch 1,947.00 $1.10 $2,141.70 LS Erosion Control (Hay bale or fabric) 1.00 $500.00 $500.00 LF Remove & replace wood/brick fence 20.00 $50.00 $1,000.00 SUBTOTAL $50,276.70 PLUS ENGINEERING,STAKING, FEES, SUPERVISION $9,948.80 ESTIMATED TOTAL COST $60,225.50 2 COST OF DRAINAGE SWALE & ENLARGED INLET - LEE ELEMENTARY FROM NORTH BOUNDARY OF FOOD LION SiTE TO SOUTH BOUNDARY OF MEADOWRIDGE TOWNHOMES ITEM QUANTITY UNIT TOTAL SWALE/ENLARGED INLET SYSTEM FEQLIFED PRICE COST LF 60" RCP 37.00 $95.00 $3,515.00 LS Connect to exiting 60' RCP 1.00 $1,500.00 $1 500.00 EA 8' x 8' Wye Inlet 1.00 $6,000.00 $6 000.00 CY Excavation for Swale 1,350.00 $1.50 $2 025.00 SY Hydromulch 3,245.00 $1.10 $3 569.50 LS Erosion Control (Hay bale or fabric) 1.00 $1,000.00 $1 000.00 LF Remove & replace wood/brick fence 20.00 $50.00 $1 000.00 SUBTOTAL $18 609.50 PLUS ENGINEERING,STAKING, FEES, SUPERVISION $3 581.25 ESTIMATED TOTAL COST $22,190.75 offsite cost compare/slcjv - 10/17/90 - PAGE I