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HomeMy WebLinkAboutDrainage LetterKLING ENGINEERING & SURVEYING Consulting Engineers • Land Surveyors 4101 S. Texas Avenue, Suite A Bryan, Texas 77802 S.M. Kling, R.P.L.S. Fred Paine, P.E., CFM Memo: Telephone 979/846 -6212 Fax 979/846 -8252 To: City of College Station, Engineering c/o Josh Norton From: Fred Paine, P.E. Re: Panera Bread Site Plan - Case file #11 00500095 Drainage Letter Post Office Box 4234 Bryan, Texas 77805 July 18, 2011 Purpose: To address the Tributary to Burton Creek Culvert Crossing & existing structures with respect to proposed fringe fill. I. The Culvert Crossing was designed, permitted & approved through the City & FEMA accounting for a fully filled floodway fringe for both sides of the Tributary (Ref.: FEMA LOMR Case No. 07- 06- 1928P). As indicated in the LOMR study, a fully filled floodway fringe creates a calculated water surface elevation of 275.5 just upstream of the culvert structure. The top of the roadway over this structure is at approximate elevation 282.5. No adverse impacts or increase in water surface elevation above the calculated amounts are anticipated from the proposed fringe fill & retaining wall. II. The adjacent structures on April Bloom appear to range in finished floor elevation from 283 to 285 according to the City of College Station digital topography. As indicated in the above referenced LOMR, a fully filled floodway fringe will not impact the April Bloom structures. Floodway elevations in this reach range from 282.5 to 280.6. Attached are the results of a modified floodway HEC -RAS run in which the proposed fill and wall were modeled by modifying sections 11 +60 through 15 +04 (right side fill only) with the remaining downstream floodway fringe fully filled. The results were only slight increases in water surface elevation (none exceeding the established floodway elevations) and a slight water spread at station 11 +60. The water spread did remain on Block "Y ". No adverse impacts are anticipated from the proposed fringe fill & retaining wall to the existing structures on April Bloom. "or. ALFRED A. PAINE � f o • • 7221 . F- 07100« SOW Sta W.S. Rgt 1 1 (u) 287.601 280.00 1 Z 1."0LE 00 '69£ IEC9LE 264.001 289.48 100'06Z 1141.3E 00'LZE 277.221 100"9£3 6£'38Z 275.001 388.87 00'89£ 1 L 1.'ELE L_ 373.001 90'L91. 03"£91. 289.651 11.0'683 1-_ 421.61 18E "1317 Enc Sta R 1 1 (u) 280.001 359.001 264.001 100'06Z 1001 7.E 236.00 275.00 00'88£ 1 00'ELE a MS 40 1 (u) 280.001 280.001 100'69£ 359.001 264.00 264.00 100 "063 100 "063 100 ".Z£ 1001.3E 00"9£3 236.001 250.00', 250.00 00'88E 00 00'89£ 368.00 00 "901. 00 '901. 00'38 1 00'38 00'LL1. 001L1. Ch Sta L 1 (u)_ 108'361. 108'361. oo'Esz 1 oo E83 231.001 231.00 230.00 230.00 00'913 215.001 174.00 00 235.00 00'9£3 1 352.00 00'Z9£ 1 001E 1 347.00 00'68 00'68 00'99 00'99 00'Z8 00'38 1 Enc Sta (u) 100' OL 245.001 100'981 100'0£3 100"91.3 00 '0L 1 210.00 345.00 00'00E 00'39 00 "8V 1 08'38 Sta W.S. Lft LO '3E 100'OLi. 169 '38 100'943 8'178 100'98 L 139'E81. - 230.0)0 215.00 146.471 00'OLL 84'0.2 210.001 1 248.701 r 345.00 246.66 300.00 00'39 91 99'9Z 00'84 3E' L8 1 08 "38 1 14681 0 80'L 19'17 39 "96 6L"617 176 •91.1. 1717'091. ZO'0 91."8 £3 99'981. 81.144 EL'1.£9 1 635.74 60'89 1119 Q Channel 1 (Sjo) 475.261 199'11.8 464.841 727.241 479.881 163'L39 00'1476 00'1.1 941.00 941.00 850.75 617'836 38'939 L9 "999 89 "6317 6 1.'8LL 1 429.94 1.6'E8E 86 "999 17£ Z6'E9L 8.'991. 1.6 •OLE 63' LL£ 1 lief 0 458.661 11,E'6Z1 471.541 19L'£1.3 365.511 1 LEE LE 917'017 1.931. E3'861. 1 224.89 1.E'9E17 1.8'L8 1.6'L317 98'6917 L17'EZ1. 817'914 96'0. L17'179 00'0 1 1N 41PM dal Z9'993 100'013 287.431 100'4.4 100 100'174 00'44 1717 00'41' 91'0£1. 00'99 1.33. 00 "99 L L"OV 1. 00 917"931. 00'EL 90'914 17.'044 66t93 1.0'1.173 9L'E91 09'1.91. 1 "TM 110 270.731 V1.143 196' LIZ 272.221 272.071 1 L0'ZLZ 91 "3L3 91.'ZLZ 0£'083 33 "083 1 1 06'08Z 1 06'08Z Prof Delta WS 1 1 £17"0 88"0 1E6'0 - Z6'0 8 "0 EL'0 L9 "0 69 "0 98'0 80'0 Z0'0 1.0'0 W.S. Elev 1 1EL "OLZ LI: La LV"ELZ 274.341 10Z1LZ 3 1.'9LZ 274.381 275.301 1 laninO 274.711 275.54 Z6'4LZ 275.651 LZ'9LZ 275.94 ZZ"LLZ 1.8'LLZ 277.37 £Z'8LZ OE '083 ZZ'08Z 281.86 281.84 170'Z8Z 30'Z8Z GI9ad Z dd 3 dd 1. dd add L dd 3 dd 1. dd add LAd add 1. Ad Zdd'. . dd 3 dd 1.dd1 add Ldd 3 dd add LAd 1. dd 3 dd 1. dd Zdd River Sta 1 0 0 91.3 1 912 1 L9E LSE 1 E61: 661 1 31.9 1 ZE9 369 �I 1799 1799 3£9 369 1.361 L361 0661 066 0914 0911 179£1.1 178£1 I 170911 17091. 4oeea 1.-43eea 1 1-4oe% 1 t.-yoeea 1 1.-4oeea 1. 1.-4neab 1. 1 1. - 4aeea 1 L-4oeaa 1 1.-4oeaa I . . I. 1 -4oeea 1 1 Reach -1 .-4oeea 1 1 Reach -1 1 - 4oeea 1 1. 1. 1. L 1. 1 RReach-1 1 1 -4oeea 3 3