FYI… Clay Barnett, P.E. Town Engineer Town of Addison 16801 Westgrove Drive Addison, TX 75001-2818 Office: (972) 450-2857 From: Lawrence A. Cates [mailto:lcates@lca-dallas.com] Sent: Wednesday, September 01, 2010 11:03 AM To: Clay Barnett Subject: FW: Addison Drainage Clay, thanks for the review. We have made all the revision you asked for and will resubmit this week. I did take a look at the drainage pattern you commented on. The existing roof drainage at the old building is rather strange. I’ve done a lot of retail, but haven’t seen this pattern. All the drainage is accommodate by several small internal downspouts located around the entire perimeter of the site. You can also see the scuppers around all sides of the building. The downspouts on the east side discharge 3-4 feet above the sidewalk. I have tried to show a comparison of pre vs. post redevelopment on the attached drawing. Based upon the location and number of existing downspouts, I have made a best guess of the actual roof drainage pattern. Since the downspouts are all the same size and actually discharge through the curb on the west and north sides, I have shown the areas at the front of the building that discharge flow to the front parking area. The actual difference in flow to the inlet at the northeast corner is less than 0.5 cfs ( 100 year). There will be some effect on the upstream hydraulics of the system, but the off-site or downstream should not be affected. Also the positive overflow at the northeast inlet is minimal. Take a look at the attached drawing and call me to discuss prior to our resubmittal. Lawrence A. Cates, P.E., R.P.L.S. Lawrence A. Cates & Assoc., LLP TBPE, Firm Registration #3751 14800 Quorum Dr., Ste. 200 Dallas, Texas 75254 (972) 385-2272 (972) 980-1627 Fax From: Mallory Luttrell [mailto:mluttrell@lca-dallas.com] Sent: Wednesday, September 01, 2010 10:55 AM To: 'Lawrence A. Cates' Subject: Addison Drainage Mallory Luttrell Lawrence A. Cates & Associates, LLP 14800 Quorum Drive, Suite 200 Dallas, Texas 75254 (972) 385-2272, Fax (972) 980-1627