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Home My WebLink About63 Development Permit 422 Post Oak Square Parking Lot ExpansionNICIPAL DEVELOPMENT GROUP 203 Holleman Drive East• College Station, Texas 77840 • 409-693-5359 •FAX: 409-693-4,24-3 August 8 , 1994 Veronica Morgan City of College Station P. 0. Box 9960 Engineering, Surveying, Planning and Environmental Consultants College Station, TX 77842 Re: Parking Lot Expansion for Post Oak Square Dear Veronica: '• A parking lot expansion is proposed for Post Oak Square, Lot 2R, Block 1, Morgan Rector League, Abstract 46, College Station, Brazos County, Texas (VOL 1202, PAGE 323). This expansion includes 20 parking spaces and two islands. A 1.5 foot wide space is proposed to be left behind the islands to allow flow along the curb. Grading is proposed to direct runoff to the southernmost comer where it drops into an inlet grate. Open area for the grate was calculated to require 298 si. A grate with 326 si is proposed for non-restrictive flow. A 1 O" RCP then routes the runoff from the inlet box at a slope of 12.73o/c1he ditch is protected from erosion by a rip- rap section and "Mirarnat" erosion control. Appro imately ten feet south of this pipe, an eroded area is to be filled and protected with "Mirarnat". J.j ib ~ ~ · ~ ~ ~ As shown on the following page, the tributary is 0.63 acres. The proposed JJ:; adds 0 .09 acres of impervious area. The flow for 10 and 100-year storms were increased 0.43 and 0 .62 cfs , respectively. These additional flows would raise the 10-year storm ditch elevation 0 .036 inches and the 100-year storm 0.048 inches. An increased flow of this magnitude should have an insignificant impact. Sincerely, Alan Gibbs /kim 000577-C.1 2-07 (21 85) MUNICIPAL DEVELOPMENT GROUP P.O. Box 9249 203 Holleman Drive East College Station, Texas 77840-9249 (409) 693-5359 TO ~IZl-tl VolX- Cdn C2£' c~ ~E ARE SENDING YOU ~ched O Under separate cover via ________ the following items: 0 Prints 0 Plans 0 Samples 0 Specifications O Shop drawings O Copy of letter 0 Change order o ___________________ _ DATE NO. DESCRIPTION ;{ J',.'P Jl THESE ARE TRANSMITTED os chooked bel"' 0 ~~<;(' ;;((b ~For approval 0 Appn. ~ § O For your use 0 Approved .. ~ O As requested 0 Returned for cc,. .s O Resubmit __ copies for approval O Submit __ copies for distribution O Return __ corrected prints O For review and comment 0 ________________ ___. ___ _ O FOR BIDS DUE ________ l9 ___ 0 PRINTS RETURNED AFTER LOAN TO US REMARKS------------------------------------ COPY TO__________________ ~ It encloeMtn are llOt H Mtad •• ~:::= ue:t=. TOO® ~r 'bb}_ Municipal Development G 203 E. Holleman Dr. College Station, TX. 77840 (409) 693-5359 Fax: (409) 693-4243 FAX TRANSMISSION COVER SHEET Date: April 10, 1995 To: Veronica Morgan Fax: Ciry of College Station Re: Post Oak Square Culvert Sender: Charlie Hastings YOU SHOULD REC"EIVE 5 PAGE(S), INCLUDING THIS COVER SrIEET. IF YOU DO NOT RECEIVE ALL THE PAGES, PLEASE CALL (409) 693-5359. CtGt C69 60t xv~ gc:91 S6 /01 /t0 ZOO® MUNICIPAL DEVELOPMENT GROUP 203 Hollemofl [)rl.;e Ea.~t • CoDege Slalion, T~os 77840 • 409-693-5359 •FAX.-409-693~24.3 Engineering, Sur.oa)ing, PIBmling md En:viron.msntal C1n11rult11us April 10, 1995 Veronica Morgan Assistant City Engineer City of College Station 1101 Texas Avenue College Station, TX 77842 Re: Post Oak Square Culvert Dear Veronica, Please review our proposal for a 4 1 x21 RCB culvert to be placed approximately 91 1 from the end of the existing 4211 RCP culvert running under Harvey Road. If this absolutely will not work please notify us as soon as possi'ble. The existing 4211 RCP culvert which runs under H~ 30 (Harvey Road) has a theoretical maximum discharge of SO cfs (at a slope of0.54%), while the proposed 41 x 21 RCB culvert has a theoretical maximum discharge of99 cfs (at a slope of l.0%). We have based our design on the theoretical maximum discharge of the existing 42" RCP, the natural slope of the ditch, and the depth of the ditch (3.2'). Please notice that the depth of the ditch places an upper limit on the size of the culvert. If you have any questions please feel free to contact me at 693-5359 or fax at 693-4243 . Your timeliness in this situation is greatly appreciated. Sincerely, d-L(!~_:; Charlie Hastings CtZt C69 60t XV3 8C =91 S6 /01 /tO Project Descrii:>tion Project File Worksheet Flow Element Me1hod Solve For Input Data Mannings Coefficient Chamel Slope Diameter Results Depth Discharge Flcwkea Wetted Perimeter Top WidU'l Critical Depth Flercent Ful Critical Slope Velocity Velocity Head Specific Energy Froude Number MUimum Discharge FUii Flow Capacity Fut Flow Sl~e FULL FLOW CAPACITY 42" Worksheet for Circular Channel b :\proj\400\2512fm .fm2 POST OAK SQUA~E CircLdar Channel Maming's FormlJa FIJI Flow caeac:i!X 0.013 0.5449% 42.00 in 3 .50 ft 74.26 cfs 9 .62 ~ 11 .00 ft 0.00 ft 2.70 ft 100.00 0.006158 ft/ft 7 .72 ftls 0.93 ft FULL ft FULL 79.BB cfs "4 74 .26 c;fs 0.005449 ft/ft Municipal Development Group ~ 1 0~:11 AM Halllltad Methods, lne. 37 Brook&ide Road Waterbury, CT 06708 (2C3) 755-1 ee6 FlgwMastcr v5 .0 7 P age 1 cf 1 coo~ ct z t C69 60 t XV d 8C =91 S6 /01 /t0 4' x 2' RCB Cuhtert Worksheet for Irregular Channel Project Description Project File Worksheet Flow Element Method Solve For Input Data Chamel Slope c:'tlaestad\fmw\postoak.fm2 POST OAK SQUARE RCB lrregLiar Chamel Maming's FormLia Discharge Water SLl'face Elevation Elevation range: 0.00 ft to 2.00 ft. 1.0000 % 2.00 ft Station (ft) elevation (ft) 0 .00 0 .00 S1art Station 0.00 4.00 0.00 ReSIJts 4 .00 0.00 0 .00 Wtd. Martings Coefficient Oischarge Flow Area Wetted Perimeter Top Width Height Critical Depth Critical Slope Velocity Velocity Head Specific Energy Froude Number Ful Flow Capacity flow is sueeraitical. 2.00 2 .00 0.00 0.012 99.06 8.00 B.00 4 .00 2.00 2..00 cfs • ft2 ft ft ft ft 0.010000 ft/ft 12.38 ft/s 2 .38 ft 4.38 ft 1.54 75.60 cfs l\llunlelp:il Oeveiopmerit Group End Station 0.00 ~ 10:C3:21 AM 1-!aestad Methoda. Inc. 37 Brook11 ide Road Waterbury, CT 06708 (203) 755-161S8 Roughness 0 .012 FlowMa9tl!!r "'5.07 Page 1 of1 t oo 121 Ct~t C69 60t XV 3 SC =91 S6 /0T /t 0 ~ ·t . . .. . 'Ii' .. ~· . . § N r a 0 c., -f ~ ..... 'i 'o ,... 1(1 ~ '-'Pl .... 0 -1 '-cc • (JI ·x '! .... 0) ~I .. c.> QO ..., > ~ • ~ •19" Wv749.BJ' f: 0 cc 0) cc c.> ... ~ --~r~~--+-~~..._~~~ £ "" ~ ~"''"· l/""' c.> ~. •r Q'lllt!7 __ •-__ _ . ------c t;i:: t1 c;) \ 0 i CJ) ; ~ i§l 0 -t-~i 0 ~ (JI -~---~-~~-------------- MUNICIPAL DEVELOPMENT GROUP 203 Holleman D rive E ast• Colleg e Station, Tex as 77840 • 409-693-5359 •FAX: 409-693-4243 August 16 , 1994 Veronica Morgan City of College Station P . 0 . Box 9960 Engineering, Surveying, Planning and Environmental Consultants College Station, TX 77842 Re: Parking Lot Expansion for Post Oak Square J Dear Veronica: A parking lot expansion is proposed for Post Oak Square, Lot 2R, Block 1, Morgan Rector League, Abstract 46 , College Station, Brazos County, Texas (VOL 1202, PAGE 323). This expansion includes 20 parking spaces and two islands. A 1.5 foot wide space is proposed to be left behind the islands to allow flow along the curb. Grading is proposed to direct runoff to the southernmost comer where it drops into an inlet grate. Open area for the grate was calculated to require 298 si. A grate with 326 si is proposed for non-restrictive flow. A 10" PVC then routes the runoff from the inlet box at a slope of 12 . 73% and a velocity of 13 :ft/s. The ditch is protected from erosion by a rip-rap section and "Miramat" erosion control. Approximately ten feet south of this pipe, an eroded area is to be filled and protected with "Miramat". As shown on the following page, the tributary is 0 .63 acres. The proposed parking adds 0 .09 acres of impervious area. The flow for 10 and 100-year storms were increased 0.43 and 0.62 cfs , respectively . These additional flows would raise the 10-year storm ditch elevation 0.036 inches and the 100-year storm 0.048 inches. An increased flow ofthis magnitude should hav e an insignificant impact. ~c}Jd;A Alan Gibbs /kim 000577-C . l 2-07 (2185) Rational Method (Q = CIA) Pre-Development Area Description {acres) Q C{area) Landscaping 0 .10 0 .35 0.04 Impervious Area 0.53 0.90 0.48 0 .63 0 .51 Cavg = 0.51 I 0 .63 = 0 .81 Post-Development Area Description {acres) Q C{area) Landscaping 0.01 0.35 0.00 Impervious ··Area 0 .62 0.90 0.56 0.63 0.56 Cavg = 0.56 I 0 .63 = 0 .89 Runoff Frequency Intensity* Cpre Cpost Qpre Qpost {years) {in/in) {cfs) {cfs) 100 12 .6 0 .81 0 .89 6 .45 7.07 50 11 .1 0 .81 0 .89 5 .68 6 .23 25 9 .9 0.81 0 .89 5 .07 5 .56 10 8 .6 0 .81 0 .89 4.40 4 .83 5 7 .7 0 .81 0.89 3 .94 4 .32 MUNICIPAL DEVELOPMENT GROUP 203 H olleman Drive East • Co llege Station, Tex as 778 40 • 409-693-5359 • FAX: 409-693-4243 August 8, 1994 Veronica Morgan City of College Station P. 0. Box 9960 Engineering, Surveying, Planning and Environmental Con s ultants College Station, TX 77842 Re: Parking Lot Expansion for Post Oak Square Dear Veronica: r A parking lot expansion is proposed for Post Oak Square, Lot 2R, Block 1, Morgan Rector League, Abstract 46 , College Station, Brazos County, Texas (VOL 1202, PAGE 323). This expansion includes 20 parking spaces and two islands. A 1.5 foot wide space is proposed to be left behind the islands to allow flow along the curb. Grading is proposed to direct runoff to the southernmost comer where it drops into an inlet grate. Open area for the grate was calculated to require 298 si. A grate with 326 si is proposed for non-restrictive flow . A 1 O" RCP then routes the runoff from the inlet box at a slope of 12.73o/c The ditch is protected from erosion by a rip- rap section and "Miramat" erosion control. Appro imately ten feet south ofthis pipe, an eroded area is to be filled and protected with "Miramat". io ~ ~ · :i&o ~:: ,.,. As shown on the following page, 1he tributary is 0.63 acres. The proposed p~ adds 0.09 acres of impervious area. The flow for 10 and 100-year storms were increased 0.43 and 0.62 cfs , respectively. These additional flows would raise the 10-year storm ditch elevation 0.036 inches and the 100-year storm 0.048 inches. An increased flow ofthis magnitude should have an insignificant impact. Sincerely, Alan Gibbs /kim 0005 77-C.12-07 (2 185) ' '