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HomeMy WebLinkAbout68 Development Permit 410 Lone Star PavillionW .. CITY OF COLLEGE STATION ~ hat om-a. 9110 1101 T~• AVWtue CoJl .. c ltacton, Tau ??Ml-IHO . CoDece StltimJAB.JLimitld Pmtnenhlp A Delawsre Lum.d Pmnerthip Attn: Mt. Chui• W. Shean 1325 La Cindw Houstm, T ... '77054 ·(Mt) 76'-HOO It is mdemcod and nnmlll]y lo-i that CcUJe11 S~A.B./Limiied Parmenhip, • Delaware Limited Pannersbip, will particip& in the consuuction of & stonn drain !om ibe curb inlet b:aed ar 1be in1e1SC1ian af'Uncola Awnue aacl Posw A~ 1a 1be STorm drain system loc:aied wilhin 1he Teas Avenue riabt-af'-way . The Limited Pannenhip qrais 1D financially partigpate in m amount the equall lt\y pttc:em (SO%) of the total CCDIU'\l=lcin cost up 10 I mmamum af'ten thousand dollUJ (Sl0,000). kL KmrM.Lua~ City Enamecr j A Date of' Sipiature: / 4 / f ,, r i College Station/ AB./Limrtcd Partnership~ a Delaware linDted pannenhip. By: A.B . Open.tions, Inc .~ a Delaware Corporation . ::JZ~ Name : }<-.~.l lJ1V\'f Z? Its: 5r . V. f Date of SipatUre: P--21/ -9 6 Home of T••• A'M Unlvet1lty i'.'0 0 ~ SJAS .L N3:JM 013A3G +-+-+-MD ~N iddOHS S:V TSO T 6 96 !IOi'.'D, 6i'.': GT 96 /ti'.'/i'.'t ----------- Basic Outlet Structures E Orifices • Opening perpendicular to water surface • Opening parallel to water surface H H Orifice Area\ Submerged Outfall ~ Flow., 1---------;;;~;·c;~;~l-'¥-Z... :c ~\_Centroid of Orifice E Orifice Rating Curve 11hele: 10-3 Equation Flow, Q H /Orifice Area I _l_ I o.s c • Conlnidion l Engergy Loss Coe!f. a= CA(2gH) A·ElediveOriceAnla rr7:~"7TTTTTT7"TTY"T7'..,..,..,.,..,...,...,...,.~ ~~~~~ Free Outfall (Reprinted from Pond-2 Manual) Haestad Methods , Inc. 10 -3 g. kalleration clle kl~ H • Orifice Head 1-800-727-6555 t c • LONE STAR PAVILION FINAL DRAINAGE ENGINEERING REPORT COLLEGE STATION, TEXAS WILSON\ZETTY/ASSOCIATES 3100 WILCREST DR. SUITE 325 HOUSTON, TEXAS 77042 (713) 952-8600 APPROV D FOR :r ' . -• I " ... PURPOSE: FINAL DRAINAGE ENGINEERING REPORT LONE STAR PAVILION SHOPPING CENTER COLLEGE STATION, TEXAS 01/20/96 The purpose of this engineering report is to outline and discuss the development and drainage proposed for the Lone Star Pavilion, College Station. GENERAL LOCATION: 1. The Lone Star Pavilion will be located at the Northerly corner of the intersection of Lincoln Ave. and Texas Ave., wrapping around the existing Red Lobster Restaurant located on the corner proper. 2. According to FIGURE II-1 in the City of College Station's Drainage Policy and Design Standard Manual, the drainage from this property is in Basin 2 with primary drainage way being Wolfpin Creek and the secondary drainage way being Wolfpin Creek Tributary C. The route of the secondary drainage way was received from the Texas Highway Department, 3 . The Existing 707 Center facing on Texas Ave. adjoins the proposed development on it's northwesterly property line. The property adjacent to the subject project on the northeasterly property line is undeveloped at the present time. Across Lincoln Ave. is an apartment project. PROPERTY DESCRIPTION: 1. The Lone Star Pavilion Shopping Center will consist of the construction of a retail shopping center and parking lot on a 9.270 acre tract of land. 2. 1.0812 acres are covered by existing pavement northeast of the Red Lobster Inn, which will remain and be incorporated into the proposed parking lot. Two e x isting buildings with parking facilities on 0.7719 acres of land that fronts Tex as Ave. will be removed and rebuilt as part of the proposed parking lot. The remaining 7.4169 acres of undeveloped raw land will be used for parking lot, retail shopping center building, and detention pond. 3. The owner is Charlie Shears, Shears Interests, 13 2 5 La Concha, Houston, Texas 77054 . 4. The subject property is properly zoned for the commercial use for which this project is proposed. 1 . r ·, .' ·. PRIMARY DRAINAGE BASIN DESCRIPTION: 1. Basin 2 is gently sloping to Wolfpin Creek, which flows easterly, with a variety of land uses. 2. No related previous drainage studies exist, drainage maps for Texas Ave. prepared by the Department. except for the Texas Highway 3. The proposed development is located on Flood Insurance Map No. 48041C0144 c, effective date July 2, 1992, and is shown to be in zone X, which is outside the 500-year flood plain. SECONDARY DRAINAGE BASIN DESCRIPTION: The general off-site drainage crosses the subject property from the 707 Center on the northwest and the undeveloped land on the northeast. This runoff is presently being carried by an existing swale running from the northwest property line to an existing storm drainage inlet on Lincoln Avenue which appears to be satisfactorily handling the existing runoff. There is an existing 24" diameter pipe leaving this inlet, which connects to an existing inlet on the northeasterly side of Texas Avenue. According to the survey by Municipal Development Group, the slope on this pipe is 0.62 %. The capacity of this pipe, using an n factor of 0.013, without head, is 17.8 cfs., with 0.76 feet of head the flow is 20.6 cfs. At this elevation the water will flow into the street, which it presently does. The flow l·ine of the pipe at the inlet on Lincoln is 317.80 and the street elevation at the inlet is 320.56. The runoff from the 707 Center (area A) will be piped across the subject property using a 24" RCP@ 0.646 %, which is capable of handling 18.18 cfs without head (approx. 5 year storm). To achieve the 10 year storm run-off, the 24" will require 0.85 feet of head. The restrictions of the out fall elevation and the pipe cover in the north end of this pipe will not allow the slope to be increased. The flows using a minimum Tc of 10 min. are as follow; FLOW FROM AREA A CiA = Q Flood c i A (ac) Q (cf s) 2 year 0.65 6.3 3.71 15.19 5 0.65 7.7 3.71 18.57 10 0.65 8.3 3.71 22.02 25 0.65 9.8 3.71 23.63 50 0.65 11.1 3.71 26.77 100 0.65 12.6 3.71 30.38 2 : . ._ .. The 10 year storm runoff from the undeveloped land on the northeast (area E) will be intercepted by a back-slope trench and delivered by an 12 11 pipe to the pond outfall .structure and a 24" pipe to the existing inlet. The back-slope trench inlet is designed to allow the runoff above the 10 year storm to enter Lincoln Ave. and be carried down the pavement, as it normally does at the present. The flows for this undeveloped area using a min. of 10 min. Tc are as followi FLOW FROM AREA E Ci A = Q Flood c i A (ac) Q (cf s) 2 year 0.35 6.3 2.95 6.51 5 0.35 7.7 2.95 7.95 10 0.35 8 .3 2.95 8.57 25 0.35 9.8 2.95 10.12 50 0.35 11.1 2.95 11.46 100 0 .35 12.6 2.95 13.01 Back-slope Trench side slopes = 2:1, bottom 2', slope = 0.25%, n = 0.02 Q = 13 .98 cfs at depth of 1.15' DEVELOPMENT CRITERIA REFERENCE AND CONSTRAINTS 1. Regulations -The drainage system for the proposed development was simplified and standard criteria was met by diverting the runoff from off-site property from consideration in the development runoff calculations . Thus, the pre-development and the post development runoff discharges remain unchanged. 2. Development Criteria Reference and Constraints a. There were no previous drainage studies for the property under consideration. b . By achieving parity between the pre-development and post development runoffs, the impact of this project on existing street and drainage systems is held to a minimum. 3 •• 3. Hydrological Criteria 4. a. The Intensity-Duration-Frequency ( IDF) Curves were prepared using the constants obtained from the Texas Highway Department, based on Technical Paper No. 40, for Brazos County, Texas. Design rainfall 100-year~ 24 hour. b. Runoff calculation method used was the Soil Conservation Service, TR-55, which coincides with the data contained in the City of College Station Designs Standards. c. The Triangular and Computed Flood Hydrographs were used in conjunction with reservoir routing stage-storage-discharge relationship as found in the scs routing coefficient method. The computer software is manufactured by Eagle Point. d. The design storm recurrence intervals are 2, 5, 10, 25, SO and 100 years with 24 hour duration. e. Standard calculations were used in this design. Hydraulic Criteria: a. The capacities of the piping in the front parking lot were determined using graphs based on Manning's formulas (n=0.013), for Reinforced Concrete Pipe. Dia. Slope Q (full) 18 II 0.7% 8.79 cfs 24 11 0.31% 12.59 cf s 24" 0.646% 18.18 cf s 36 II 0.35% 39.58 cf s 3 0 II 1.50% 50.19 cf s Capacities for piping at the rear of the buildings. Dia. Slope Q (full) 30 II 0.95% 39.95 cf s 12" 4.72% 9.22 cfs b. Detention Pond at the Rear of Buildings: The detention at the rear of the buildings uses a grass bottomed pond with side slopes of 3:1 and a lateral slope at O. 5%. The entire pond will be reinforced with "Pee-Mat" 11 Greenstreak 11 as manufactured by American Excelsior Company. This product has passed Tex DOT tests and is on their approved materials list. At an elevation of 326.5, the maximum depth at the southerly end of the pond, the capacity of the pond is 65209 cubic feet. The out-fall facility shall consist of a 1.00' high by 0.694' .wide opening flow line at elevation 321.2 i with a ~.45-2a-' wide Cipolletti weir crest elevation at 3 24 .4'4 . I c./{qf 4 : RUNOFFS FOR AREAS c & D EVENT Q CPRE Q DPRE TOTAL PRE Q C po sT Q Dpos T TOTAL POST 2 YEAR 8.12 9.47 17.59 14.07 17.58 31.65 5 9.93 11.57 21.50 17.20 19.83 37.03 10 10.70 12.47 23.17 18.54 21.38 39.92 25 12.64 14.72 27.36 21.89 25.24 47.13 50 14.31 16.58 30.89 24 :r9 28.59 53.38 100 16.25 18.93 35.18 28.14 32.45 60.59 PROPOSED DISCHARGES EVENT PARKING LOT DETENTION POND TOTALS 2 YEAR 10.90 6.69 17.59 5 13.32 8.18 21.50 10 14.36 8.81 23.17 25 16.95 10.41 27.36 50 19.14 11.75 30.89 100 21.80 13.38 35.18 The Detention Pond was lengthen 18. 5', and re-sloped the parking lot which increases the volumes that were used in the December 26, 1996 report. INCREMENTAL VOLUMES OF THE DETENTION POND ELEVATION VOLUME 321.50 437.5 CF 322.00 2541.5 322.50 5401.6 323.00 9161.9 323.50 13797.8 324.00 19527.5 324.50 26484.6 325.00 34607.5 325.50 43820.5 326.00 54046.4 326.5 65209.0 5 . ' ·. VOL. = EVENT 2 5 10 25 50 100 2 YEAR REQUIRED DETENTION POND 1/2 x 2TP X 60 x ( QPOST -QDISCH.) QPOST -DISCH. = DIFF. x TP X 60 REQUIRED VOL. ELEV. 17.58 6.69 10.89 37.20 24306 C.F. 324.34 19.83 8.18 11.65 48.52 33915 324.96 21.38 8.81 12.57 55.32 41722 325.39 25.24 10.41 14.83 57.15 50852 325.69 28.59 11.75 16.84 56.92 57512 326.16 32.45 13.38 19.07 56.98 65196 326.50 (ACTUAL 65209) DETENTION POND OUT FALL CALCULATIONS Q = 6.86; ELEV. = 324.36; FL ELEV. = 321.21 1.0' HIGH X 0.694' WIDE RESTRICTER OPENING FL ELEV. = 321.21 TOP ELEV.= 322.21 h = 324.36 -322.21 = 2.15' Q Ca (2gh)iiz = 0.82 X .694 X 11.76 6.69 OK 100 YEAR Q = 13.66; ELEV. 326.50 h 1 = 326.50 -322 .21 = 4.29' Q1 Ca (2gh)112 = 0.82 X .694 X 16.59 = 9.44 326.50 -324.64 = i.86' Q2 3 . 3 6 7 X B ( h) 312 = 3 . 3 6 7 X . 4 61' X ( 1. 8 6) 312 = 3 . 94 QTOTP..L = 9.44 + 3.94 = 13.66 OK 6 FLOW OVER WEIR PLUS FLOW THROUGH RESTRICTER OPENING EVENT ELEVATION QTOTAL QMAXIMUM 5 YEAR 324.95 7.91 < 8.18 10 325.38 9.21 > 8.81 25 50 VOL = EVENT 2 5 10 25 50 10 0 325.83 10.25 < 10.41 326.14 12.06 > 11.75 If the water level goes higher than 326.5, the over-flow will discharge back through the curb cuts into the back parking lot and into Lincoln Ave. c. Detention in Front Parking Lot: The front parking lot is divided into nine areas plus 242.00 lf of 36" and 260.00 lf of 24" RCP connecting the inlets in these areas. which will also be used as detention. The volumes were calculated with 10'' of water standing over the inlets tapering out to the base of the proposed curbs. Therefore, automobiles will be parking in less than 3" of standing water. The flow from the front parking lot will be restricted in the junction box near the existing inlet on Lincoln Avenue. DETENTION OUT-FALL FACILITIES FOR PARKING LOT The out-fall facilities shall consist of an 12" pipe set at elevation 318.04 and a Cipolletti weir with its 5.97' crest at elevation 323.36, in the junction box near the existing inlet on Lincoln Ave. The ma x imum water level will be 324.00 . REQUIRED PARKING LOT DETENTION 1/2 x 2 TP x 60 x ( QPO ST -QDISCH . ) QE'OST -DISCH. = DIFF. X TP X 60 = REQUIRED VOL. ELEV. 14.07 10.90 3.17 35.19 6693.1 C.F. 323.36 17 .2 0 13.32 3.88 41.44 9647.2 323.53 18.54 14.36 4.18 46.78 11732.4 323 .65 21.89 16.95 4 .94 47.86 14185 .7 323.79 24.79 19.14 5 .65 47. 41 16043 .5 323.90 28.14 21.80 6.34 47 .30 17992.9 324.00 (ACTUAL 18003.13) 7 -. ·. 2 YEAR 100 YEAR WEIR PARKING LOT OUT FALL CALCULATJONS Q = 10.73; ELEV. = 323.36; FL ELEV. = 318.04 12" RESTRICTER PIPE -FL ELEV . = 318 .04 TOP ELEV. = 319.04 h = 323 .36 -319.04 = 4.32' Q =Ca (2gh)1 12 = 0.82 X .785 X 16.67 = 10 .73 OK Q = 21.52; ELEV. 324.00 h 1 324 . 00 -319 . 04 = 4. 96' Ca ( 2 g h) 112 = 0 . 8 2 X . 7 8 5 X 1 7 . 8 6 = 11.50 h 2 = 324.00 -323.36 = 0.6 4 ' Q2 = 3 .367 X B (h)312 = 3.367 X 5.97' X (0 .5 1 2)312 = 10.29 Q ":'OT.".L = 11. 50 + 10 . 02 = 21. 79 OK FLOW OVER WEIR PLUS FLOW THROUGH RESTRICTER PIPE ELEVATION Q '!'OTP<.L 323 .5 11.95 323.6 13 .39 323 .7 15.13 323 .8 17.13 323 .9 19 .36 8 FLOW FROM AREAS THAT CONTINUE TO DRAIN AS THEY DO AT PRESENT Year C i A (to Texas) A (to Lincoln) Q (Tex.) Q (Linc.) 2 5 10 25 50 100 0.75 6.3 7.7 8.3 9.8 11.1 12.6 0.8781 ac. 0.8861 ac. 4.15 cfs 5 .. 07 5.47 6.45 7.31 8 .30 FLOW FROM AREAS THAT WILL BE REROUTED TO PROJECT 4.19 cfs 5.12 5.52 6.51 7.38 8.37 Year C i A (from Linc.) Q (C 1 ) 2 0.75 6.3 0.1710 ac 5 7.7 10 8 .3 25 9.8 50 11.1 100 12.6 0.81 cfs 0.99 1. 06 1. 26 1.42 1. 62 The proposed parking lot in front of the shopping center will have nine separate detention ponds, all with the same low point elevation at inlets and will be drained by pipes to the existing inlet on Lincoln Avenue. All the runoff on the proposed buildings and behind the buildings will be subject to a detention pond to be constructed adjacent to the northeasterly property line. b. The off-site runoff from the undeveloped property to the northeast, will remain the same. The total discharge from the front parking lot and the discharge from the detention pond will be equal to the runoff which occurs at the present time, plus the drainage that has been rerouted from the existing paved area being repaved. The runoff from the off-site properties that flow across this project at the present time have been rerouted through the subject property so as not to affect the drainage system of the proposed development. c. The development is broken into five areas . Pre- development consists of Area A (the 707 Center) . Area B (the property being developed) ,and E (the undeveloped land on the northeast) . Area B is further divided into Area c and Area D. Area C is the raw land in front of the proposed shopping center buildings that does not have existing pavement on it. Area D is the raw land that has the proposed buildings, the rear parking lot and pond on it. 10 ·. The post development consists of Area c (same as above), Area C1 (that portion of the pavement that is in the parking lot behind Red Lobster which has been rerouted to the front parking lot system, and C2 (0.0955 acres that has been rerouted to drains to Red Lobster driveway) and Area D (the same above) . These areas are marked on tne accompanying maps. Unit Hydrographs and Flood Completed Hydrographs were prepared for each analysis area and combined where appropriate. The various storms were routed through the detention ponds. PRE-DEVELOPMENT RUNOFF -UNDEVELOPED AREA C Year c i A Q 2 0.40 6.3 2.9024 ac 7.31 cfs 5 7.7 8.94 10 8.3 9.64 25 9.8 11.38 50 11.1 12.89 100 12.6 14.63 PRE-DEVELOPMENT RUNOFF -UNDEVELOPED AREA D Year c i A Q 2 0.35 6.3 4.2927 ac 9.47 cf s 5 7.7 11.57 10 8.3 12.47 25 9.8 14.72 50 11.1 16.58 100 12.6 18.93 PRE-DEVELOPMENT -PRE-DEVELOPMENT RUNOFF -AREA C TOTAL Year Area c AREA C1 AREA TOTAL AREA c 2 7.31 cfs 0.81 cf s 8.12 cf s 5 8.94 0.99 9.93 10 9.64 1. 06 10.70 25 11.38 1.26 12.64 50 12.89 1.42 14.31 100 14.63 1.62 16.25 11 Soil Conservation Service, Technical Release no. 55 Q (inches) = (P -0.2 S)2 I (P + 0.8 S) s (1,000 I CN) -10 PRE-DEVELOPMENT VOLUME FOR AREA c Year p CN Q (inches) Area 43560/12 Volume 2 4.5 75 2.05 x 2.9024 x 3630 = 21598 cf 5 6.2 3.46 36454 10 7.4 4.51 47516 25 8.8 5.77 60791 50 9.8 6.69 70484 100 11. 0 7.82 82389 PRE-DEVELOPMENT VOLUME FOR AREA D Year p CN Q Area Volume 2 4.5 75 2.05 4.2927 31944 cf 5 6.2 3.46 53915 10 7.4 4.51 70277 25 8.8 5.77 89911 50 9.8 6.69 104246 100 11.0 7.82 121377 POST-DEVELOPMENT RUNOFF -DEVELOPED AREA c + C1 -C2 Year c i A Q (cfs) 2 0.75 6.3 2.9779 ac 14.07 cf s 5 7.7 17.20 10 8.3 18.54 25 9.8 21.89 50 11.1 24.79 100 12.6 28.14 Soil Conservation Service, Technical Release no. 55 Q (inches) = (P -0.2 S)2 I (P + 0.8 S) s = ( 1, 0 0 0 I CN) 10 12 ' POST-DEVELOPMENT VOLUME FOR AREA c TOTAL Year p CN Q (INCHES) Area 43560/12 Volume 2 4.5 94 3.82 x 2.9779 x 3630 = 41293 cf 5 6.2 5.50 59454 10 7.4 6.69 72317 25 8.8 8.08 87343 50 9.8 9.07 98045 100 il. 0 10.27 111016 POST-DEVELOPMENT TIME TO PEAK FOR AREA C TOTAL Year Vol Q (cf s) Vol/(1.39 x Q x 6 0) = Tp (min) 2 41293 14.07 35.19 5 59454 17.20 41.44 10 72317 18.54 46.78 25 87343 21.89 47.86 50 98045 24.79 47.41 100 111016 28.14 47.30 POST-DEVELOPMENT RUNOFF -DEVELOPED AREA D Year c i A (ac) Q (cf s) 2 0.65 6.3 4.2927 ac 17.58 cf s 5 7.7 19.83 10 8.3 21.38 25 9.8 25.24 50 11.1 28.59 100 12.6 32.45 Post-DEVELOPMENT VOLUME FOR AREA D Year p CN Q Area Volume 2 4.5 91 3.50 4.2927 54538 cf 5 6.2 5.15 80249 10 7.4 6.33 98637 25 8.8 7.72 120296 50 9.8 8.71 135723 100 11.0 9.90 154266 13 POST-DEVELOPMENT TIME TO PEAK FOR AREA D Year Vol Q (cfs) Vol/(1.39 x Q x 60) = Tp (min) 2 54538 17.58 37.20 5 80249 19.83 48.52 10 98637 21.38 55.32 25 120296 25.24 57 .. 15 50 135723 28.59 56.92 100 154266 32.45 56.98 d. The drainage patterns are as follows; 1) the off-site runoff has been rerouted to remove them from the design consideration for this project, 2) portions of existing pavement runoff will be allowed to flow to Tex as Ave. and Lincoln Ave . as it does at present, which removes it from the design considerations for this project, with the remainder being included in the front parking lot system, 3) the 225' adjacent to Texas Ave. that is being redeveloped as part of the parking for this project will be allowed to sheet flow to Texas Ave. which is the direction of its runoff at the present time . 4) the runoff from the front parking lot will be detained in nine separate ponds on the pavement and piped to a junction box in front of the existing inlet on Lincoln Avenue, 5) the building and back parking lot runoffs will be detained in a detention pond located adjacent to the northeast property line, and 6) the off-site runoff from the adjoining undeveloped property on the northeast side of the project will be intercepted by a back-slope trench and taken into the system by use of an open sided inlet which will allow a portion of the flow to enter Lincoln Ave. without causing a strain on the drainage capacity of the existing pavement. 14 2. Specific Details: a. The drainage problems encountered in the drainage design of this project were: 1) incorporating the existing paving into the proposed new front parking lot. The existing pavement determined the elevations in the new parking lot and the elevations of all the other items in the developments. 2) determining the best method of handling the runoff from the off-site properties. To simplify the design consideration, these runoffs were rerouted around the internal drainage systems. 3) To prevent a system overload by including all of the runoff that may occur during a 100 year storm, the inlet at the end of the back-slope trench is designed to allow a portion of the runoff to pass around the open sided inlet and flow into the gutter of Lincoln Ave. which will not adversely affect the street drainage characteristics. b. Detention solution encountered the following problems; 1) The location and arrangement of the back-slope trench caused a problem in the layout of the detention pond. To allow enough room to place the back-slope trench on the proposed project property, the width of the rear parking lot was reduced. 2) The use of a detention area in the front parking lot was used, because of the restrictions imposed on the rear detention pond, mentioned above. The use of detention ponds on the front parking lot required the removal of a portion of the existing pavement to provide an adequate amount of storage. c. The arrangement of the inlets and junction boxe s in the system will facilitate easy access for maintenance. The only problem that may occur is the size of the pipe that leaves the existing inlet on Lincoln. CONCLUSIONS: 1. It is our opinion that all of the Standards of the City of College Station Drainage Policy and Design Standards have been met. 2. The effectiveness of the proposed drainage design will not allow any additional damage from storm water flows that do not exist at the present time . 15 ; 3. The proposed drainage system was designed using the 100-year storm information furnished by the City of College Station. Therefore, the development of this project will not change the runoff in the secondary system from what is experienced at present. REFERENCES: All criteria and technical information followed the guide lines of the City of College Station Drainage Policy and Design Standards and prepared using the Eagle Point software. APPENDICES: 1. Hydrologic Computations a. Land use for the 707 Center was Business/Commercial and the land use for the undeveloped property to the northeast of the project was Natural Grasslands . b. Storm water runoff (peak 100-year discharge) for; 1) the 707 Center was determined to be 30.38 cfs 2) the pre-development raw land portion runoff of the project was determined to be 35.18 cfs 3) the undeveloped off-site property to the northeast was determined to 13.01 cfs 4) post development run-off for the front parking lot was determined to be 28.14 cfs 5) detention pond maximum discharge 13.38 cfs 6) detention in parking lot max. discharge 21.80 cfs . c. The pre-developed 100 year runoff for Area c and D is 35.18 cfs and the post development discharge for Area c and Area Dis 35.18 cfs. Therefore, the project does not increase the total amount of runoff that presently occurs. 2. Hydraulic Computations: a. There are no culverts in this project. 16 ·- b. Storm Sewer Capacities 1) Pipes in front parking lot a) 18 II capacity 8.79 cfs b) 24 11 capacity 12.59 cfs c) 3 0 II capacity = 50.19 cfs d) 36 II outfall = 39.58 cfs: e) 24 11 from 707 Center; cap. = 18.18 cf s 2) Pipes from the detention pond and back-slope trench a) 12 11 capacity = 9.22 cfs; will carry 9.0 cfs the remaining 4.01 cfs (for 100-yr storm) will be discharged to Lincoln Ave. b) 30" capacity = 39.95 cfs c. Street Capacity: Lincoln Ave.; Yo= 7", Sp= 19', slope= 1.33% Q (half section) = 20.0 cfs capacity from City of College Station topo. map, the area being drained by this reach of Lincoln Ave. is 3.75 Acres Time of concentration= 300 ft. at 1 fps = 5 min + 900 ft. at 2 fps= 7.5 min Total Tc= 13.5 min. Intensity for (25-yr storm) = 8.3 in/hr Runoff coefficient; Medium density residential c = 0.55 Runoff for Lincoln Ave. = 0.55 x 8 .3 x 3.75 = 17.12 cfs d. Storm Inlet Capacity: 1) Inlets in front parking lot are all 2 foot square grate top inlet. Open Area is 75% of 4 s.f. = 3 s.f. Ag= 2.4 -25% (3) 2.25 s.f.; aver. Q = 3.17 cfs Q/Ag = 3 .1 7 I 2. 25 = 1. 41: from Fig. V-2 y = 10" 2) Inlet for back-slope trench is a box with three side open and a 4" X 3' X 3' reinforced concrete lid. Length of openings = 3 x 2' = 6' Q (@ height = 8 11 ) = 6' x 1.5 cfs/ft. = 9 .0 cfs The remaining 5.71 cfs (for 100-yr runoff) will be discharged to Lincoln Ave. gutter. 17 e. Open Channel design: Back-slope trench Q (100-yr runoff) = 13.01 cfs Trapezoidal earthen trench with 2:1 . side slopes Bottom= 2.0' Height = 1.12' p = 2 + 2(2.50') = 7.00' A 2(1.12) + 2(2.24 X 1.12)/2 4.75 s.f . R = A/P = 0. 6785; R 213 = 0. 771 n = 0.02 s = 0.25%: S 112 = 0.05 v = 1. 486/n X R 213 X s 1 1 2 v = 74.3 x 0.771 x 0.05 = 2.86 fps Q = 4.75 x 2.86 = 13.59 cfs > 13.01 cfs Therefore the height will be somewhat less than 1.15' FINAL DRAINAGE REPORT DRAWING CONTENTS: 1 . Sheet #1 -General Location Map 2 . Sheet #2 -Floodplain Information 3. Sheet #3 -Drainage Plan Map I hereby certify that this report for the drainage design of the Lonestar Pavilion Shopping Center development was prepared by me or under my supervision in accordance with the provisions of the City of College Station Drainage Policy and Design Standards for the owners thereof. ~ik:?fl li49z Registered Professional Engineer State of Texas No. 26383 ' . -~ :, .. ; . 18 FAX : Date : 1/20/96 TO: Steve Homeyer City of College Station, Texas FROM: Tom Eikel , P.E. Subject: Tele. No . (713) 988-9889 Fax No . (713) 952-8610 Corrections to the Final Drainage Report for Lonestar Pavilion All changes to the 1/10/97 Report are marked with an * The area for Post-Development Runoff for C total was an area that was carried over from a previous report that was not updated . The new calculations have required the enlargement of the parking lot detention and the detention pond at the rear . We have made changes to the construction drawings and hard copies of this report will over-nighted to your office for final review. Please look over this faxed copy of the report and give me call before we send the corrected drawings and report . Thank you for your help in this matter . Yours trul/-), _ ~ ;J I Tom Eikef' / ..,.__ ~ lo+1t I PURPOSE : FINAL DRAINAGE ENGINEERING REPORT LONE STAR PAVILION SHOPPING CENTER COLLEGE STATION, TEXAS 01/20/96 The purpose of this engineering report is to outline and discuss the development and drainage proposed for the Lone Star Pavilion, College Station. GENERAL LOCATION: 1. The Lone Star Pavilion will be located at the Northerly corner of the intersection of Lincoln Ave. and Texas Ave., wrapping around the existing Red Lobster Restaurant located on the corner proper. 2. According to FIGURE II-1 in the City of College Station's Drainage Policy and Design Standard Manual, the drainage from this property is in Basin 2 with primary drainage way being Wolfpin Creek and the secondary drainage way being Wolfpin Creek Tributary C. The route of the secondary drainage way was received from the Texas Highway Department, 3 . The Existing 707 Center facing on Texas Ave. adjoins the proposed development on it's northwesterly property line . The property adjacent to the subject project on the northeasterly property line is undeveloped at the present time. Across Lincoln Ave . is an apartment project. PROPERTY DESCRIPTION: 1. The Lone Star Pavilion Shopping center will consist of the construction of a retail shopping center and parking lot on a 9 .270 acre tract of land. 2 . 1.0812 acres are covered by existing pavement northeast of the Red Lobster Inn, which will remain and be incorporated into the proposed parking lot . Two existing buildings with parking facilities on 0.7719 acres of land that fronts Texas Ave. will be removed and rebuilt as part of the proposed parking lot. The remaining 7 .4169 acres of undeveloped raw land will be used for parking lot, retail shopping center building, and detention pond. 3. The owner is Charlie Shears, Shears Interests, 1325 La Concha, Houston, Texas 77054. 4. The subject property is properly zoned for the commercial use for which this project is proposed. 1 PRIMARY DRAINAGE BASIN DESCRIPTION: 1 . Basin 2 is gently sloping to Wolf pin Creek, which flows easterly, with a variety of land uses . 2. No related previous drainage studies exist, drainage maps for Texas Ave. prepared by the Department. except for the Texas Highway 3. The proposed development is located on Flood Insurance Map No . 48041C0144 c, effective date July 2, 1992, and is shown to be in zone X, which is outside the 500-year flood plain . SECONDARY DRAINAGE BASIN DESCRIPTION: The general off-site drainage crosses the subject property from the 707 center on the northwest and the undeveloped land on the northeast. This runoff is presently being carried by an existing swale running from the northwest property line to an existing storm drainage inlet on Lincoln Avenue which appears to be satisfactorily handling the existing runoff. There is an existing 24" diameter pipe leaving this inlet, which connects to an existing inlet on the northeasterly side of Texas Avenue. According to the survey by Municipal Development Group, the slope on this pipe is 0.62 %. The capacity of this pipe, using an n factor of 0.013, without head, is 17.8 cfs., with 0.76 feet of head the flow is 20 .6 cfs. At this elevation the water will flow into the street, which it presently does. The flow line of the pipe at the inlet on Lincoln is 317.80 and the street elevation at the inlet is 320.56. The runoff from the 707 Center (area Al will be piped across the subject property using a 24" RCP@ 0.646 %, which is capable of handling 18.18 cfs without head (approx. s year storm). To achieve the 10 year storm run-off, the 24" will require 0 .85 feet of head. The restrictions of the out fall elevation and the pipe cover in the north end of this pipe will not allow the slope to be increased. The flows using a minimum Tc of 10 min. are as follow; FLOW FROM AREA A Ci A = Q Flood c i A (ac) Q (cf s ) 2 year 0 .65 6.3 3.71 15.19 5 0.65 7 .7 3 .71 18.57 10 0.65 8 .3 3.71 22 .02 25 0.65 9 .8 3 .71 23.63 50 0.65 11.1 3.71 26.77 100 0 .65 12.6 3 ~71 30 .38 2 The 10 year storm runoff from the undeveloped land on the northeast (area E) will be intercepted by a back-slope trench and delivered by an 12" pipe to the pond outfall · structure and a 24 11 pipe t o the existing inlet . The back-slope trench inlet is designed to allow the runoff above the 10 year storm to enter Lincoln Ave. and be carried down the pavement, as it normally does at the present. The flows for this undeveloped area using a min. of 10 min. Tc are as follow; FLOW FROM AREA E Ci A = Q Flood c i A (ac) Q (c fs) 2 year 0 .35 6 .3 2 .95 6.51 5 0.35 7,7 2.95 7.95 10 0.35 8.3 2.95 8.57 25 0.35 9.8 2 .95 10.12 50 0.35 11.1 2.95 11.46 100 0. 3 5 12.6 2.95 13.01 Back-slope Trench side slopes= 2:1, bottom·2 1 , slope= 0 .25%, n = 0.02 Q = 13.98 cfs at depth of 1.15' DEVELOPMENT CRITERIA REFERENCE AND CONSTRAINTS 1. Regulations -The drainage system f o r the proposed development was simplified and standard criteria was met by diverting the runoff from off-site property from consideration in the development runoff calculations. Thus, the pre-development and the post development runoff discharges remain unchanged. 2. Development Criteria Reference and Constraints a. There were no previous drainage studies for the property under consideration. b. By achieving parity between the pre-development and post d evelopment runoffs, the impact of this project on existing street and drainage systems is held to a minimum. 3 3. Hydrological Criteria a. The Intensity-Duration-Frequency (IDF) Curves were prepared using the constants obtained from the Texas Highway Department, based on Technical Paper No. 40, for Brazos County, Texas. Design rainfall 100-yea~, 24 hour . b. Runoff calculation method used was the soil Conservation Service, TR-55, which coincides with the data contained in the City of College Station Designs Standards. c . The Triangular and Computed Flood Hydrographs were used in conjunction with reservoir routing stage-storage -discharge relationship as found in the scs routing coefficient method . The computer software is manufactured by Eagle Point. d. The design storm recurrence intervals are 2, 5, 10, 25, 50 and 100 years with 24 hour duration . e. Standard calculations were used in this design . 4 . Hydraulic Criteria : a. The capacities of the piping in the front parking lot were determined using graphs based on Manning's formulas (n=0 .013), for Reinforced Concrete Pipe . Dia. Slope Q (full) 18 II 0.7% 8.79 cf s 24" 0.31% 12 .59 cf s ~ 24 11 0.646%-18.18 cf s 36 II 0.35% 39 .58 cf s 30" 1 .50% 50 .19 cf s Capacities for piping at the rear of the buildings . Dia. Slope Q (full) 3 0 II 0.95% 39 .95 cf s 12" 4 .72% 9 .22 cf s b. Detention Pond at the Rear of Buildings: The detention at the rear of the buildings uses a grass bottomed pond with side slopes of 3:1 and a latera l slope at 0 .5%. The entire pond will be reinforced with "Pee-Mat" 11 Greenstreak 11 as manufactured by American Excelsior Company . This product has passed Tex DOT tests and is on their approved materials list. At an elevation of 326 .5, the maximum depth at the southerly end of the pond, the capacity of the pond is )f: --/65209 cubic feet. The out-fall facility shall consist of a "1. O Sl\igh by O --9-.4'/.wide opening flow line at elevation r-~2 . ~.k ith a . 0 M w\e Cipolletti we i r crest elevation at ~ 4~ Ov"-~ ""-' ~i? RUNOFFS FOR AREAS C & D EVENT Q CPRE Q D PR E TOTAL PRE Q Cpo sr Q Dpo sr TOTAL posT 2 YEAR 8 .12 9.47 17 .59 ';f 14 .0 7 17 .58 '31. 65 5 9.93 11.57 21 .50 it 17 .20 19 .83 * 3 7 . 03 10 10.70 12.47 23.17 / ;t 18 . 54 v-21. 38 * 39. 92 25 12.64 14 .72 27.36 ~ 21. 89 2S .24 )f47 .13 so 14.31 16.58 30 .89 * 24 .1 9 28.59 t 53. 3 8 100 16.25 18 .93 35.18 ":4r 28 .1 4 32.45 )1;60.59 PROPOSED DISCHARGES EVENT PARKING LOT DETENTION POND TOTALS 2 YEAR j 10 . 90 '*6.69 17 .59 5 )'13.32 ;f.8 .18 21.SO / 10 ';¥ 14.36 Xe-8 . 81 2 3 .17 25 1'16.95 1 10. 41 27.36 so .*19.14 111.7S 30.89 100 ~·21 .80 * 13. 38 3S.18 The Det e ntion Pond was lengthen ~ and ~ the parking lot which increases the volu ~ we ~ the December 26, 1996 report. INCREMENTAL VOLUMES OF THE DETENTION POND ELEVATION VOLUME 321.SO )t. 437.S CF 322 . 00' ): 2541.S 322.5 0 -* 54 0 1. 6 323.00 )f' 9161 .9 323 .50 )f 13797.8 324 .00 ... 19S27 .5 ~ 324.SO x 26484 .6 325.00 # 34607 . 5 325 .SO *43820 .S 326.0 0 # S4046 .4 326.5 't65209.0 5 REQUIRED DETENTION POND VOL. = 1/2 X 2TP X 60 X (O eos r -Oor sCH.) ...::.> ~'° EVENT Q?osr -DISCH . = DIFF . X TP X 6 0 = REQUIRED VOL. ELEV . ~ ~ . tr 2 17 .58 ~6. 69 *10 .89 37.20 ' 24306 C .F. 324.34 ¥~ 5 10 25 50 100 2 YEAR 19 .83 * 8 .18 i 11. 65 48 .52 ~33915 * 324.96 21. 38 i< 8. 81 ~ 12. 57 55 .32 t 41 722 '* 325.39 25 .24 JFl0 .41 * 14. 83 57 .15 * 50852 # 325.69 28 .59 #11.75 'lf16 .84 56 .92 # 57512 ~· 326.16 32 .45 ~13.38 f 19.07 56.98 * 65196 (ACTUAL 6 Sj 0 9 ) DETENTION POND OUT FALL CALCULATIONS Q = 6 .86; 1. 0' HIGH X ~ ELEV . = 324 .36; ,;. FL ELEV. = 321.21 -* 0.694' WIDE RESTRICTER OPENING/ FL ELEV . = 3 2 1 . 2 1 /¥-I// TOP ELEV. = 3 2 2 . 21 >r V t * ,it .J' 324 .36 -322 .21 = 2.15'.../-.~ ..>LJ ~V t x *~ Q =Ca (2gh)'~~ .694 X 11 .76 = 6 .69 OK ~ h 100 YEAR ~¥ "':(.,/ ~().,,,~~ Q = 13 .66; ELEV . 326.50 * ~ 326 .so -322 .21 = 4.29 ' 4-.S ·~ i Q ~ =Ca (2g j "12 = 0.82 X .694 -X 16 .59 WEIR h 2 = 326 .50 -324~64 /= 1 .8~,J ) = \I \\ ·\ G3 ~ Ill N W\ *~ \ ~ Q2 = 3 .367 X B (h )312 = 3 .3 6 7 X x (1 .86 )312 = 3 .9 4 * ,. .r Orc r>: = 9.44 + 3 .94 = 13 .66 0 7 , ./$ 6 '- FLOW OVER WEIR PLUS F ~W THROUGH RESTRICTER OPENING EVENT ELEVATION Q TOT AL Q MAXI MUM 5 YEAR 324. 95· j 7. 91'. '< 8. 18 * & *_9_. _21_._> _s ~ * ~c,~ ~ 10 25 50 325.38 · 10. 41 * 326 .14 . *12. 06 • > 11. 75¥ ffaJJ}l. ---------=--- '* 10 . 25 < 325.83 , o~ If the water level goes higher than 326 .5, the over-flow will discharge back through the curb cuts into the back parking lot and into Lincoln Ave. c. Detention in Front Parking Lot: The front parking lot is divided into nine areas plus 242 .00 lf of 36" and 260.00 lf of 24" RCP connecting the inlets in these areas. which will also be used as detention. The volumes were calculated with 10" of water standing over the inlets tapering out to the base of the proposed curbs . Therefore, automobiles will be parking in less than 3 11 of standing water. The flow from the front parking lot will be . restricted in the junction box near the existing inlet on Lincoln Avenue. DETENTION OUT-FALL FACILITIES FOR PARKING LOT ~ The out-fall facilities shall consist of an 12 11 pi~ set at elevation 318 .04 and a Cipolletti weir with its 5.97' crest at elevation 323.36, in the junction box near the existing inlet on Lincoln Ave . The maximum water level will be 324 .00. REQUIRED PARKING LOT DETENTION VOL = 1/2 X 2 TP X 60 X (O rosr -Oorscn .) EVENT O rosr -DISCH. = DIFF. X TP X 60 = REQUIRED VOL. ELEV. 2 *' 14. 07 ~10. 90 '* 3. 1 7 s * 17.20 *'13.32 t3.88 1.0 * 18. 54 *' 14. 3 6 * 4. 18 25 * 21..89 ~1.6.95 ~ 4.94 50 >r 24 .79 'fl9.1.4 * 5.65 lOO ~ 2s .14 f.21.so * 6 .34 35 .19 ~ 6693 .1 C .F . 323.36 41.44 * 9647.2 323.53 46.78 t 11732.4 323 .65 47.86 ~ 14185.7 323.79 47.41 ~ 1.6043 .5 3 2 3 .90 47.30 * 17992 .9 324 .00 (ACTUAL 18003.13) 7 )f 2 YEAR 100 YEAR WEIR PARKING LOT OUT FALL CALCULATIONS Q = 10.73; ELEV . = 323 .36; FL ELEV. = 318 .04 ~ 12 11 RESTRICTER PIPE -FL ELEV. = 318. 04 V/ TOP ELEV. = 319 .04 V h = 323.36 -319.04 = 4.32' ·[!! J,~£~ Q =Ca (2gh)112 = 0.8 ~X .785 X 16., = 10.73 OK Q = 21.52; ELEV. 324.00 h 1 = 324.00 -319 .04 = 4 .96' Q1 =Ca (2gh)1 ;;: = 0.82 X .785 X 17.86 :;; 11. 50 h , = 324.00 -323.36 = 0 .64' t i " 0 2 = 3.367 x B (h) ,,. " = 3.367 x 5.97' x (~))/2 = ' . to<J-' Ornv.L = 11.50 + 10. = 21.79 OK i q ~ FLOW OVER WEIR PLUS FLOW THROUGH RE STRICTER PIPE · ELEVATION Q ~C':·.;:, 323.5 ; 11.95 ~ 323.6 ~ 13.39 323.7 j 15.13 323.8 " 17.13 323.9 * 19 .36 3ic1 t;L1t\ 8 * o\:--10 .29 STAGE STORAGE FOR PARKING LOT Elevation Storage (cf) 318. 04 O (min. elev .) 318.54 56.49 319.04 267 .72 319 .54 663.80 320 .04 1213 .39 320 .54 1897.45 321 .04 2066.91 321.54 2681.86 322 .04 2739.27 (max . storage in pipes) 323 .17 (rim of inlets) ~ 323.67 + 3188 .77=12077 .39~1 ~~~ 324 .00 3188 .77 ~ 18003.13 ... ) ~~ If the water level rises above 324.00, the flow will travel nA>~ down the section of existing pavement that will remain f" undisturbed to Lincoln Ave. as it does at the present time. d. The criteria and calculation methods used agree with the City of College Station Standards. DRAINAGE FACILITY DESIGN: 1 . General Concept a. The portion of the existing pavement behind Red Lobster that is .not to be removed, will sheet flow as it presently ~ does to Lincoln Avenue . The original pavement has an area of \/" 1. 0571 acres . The final design will allow o. 8861 acres to flow as it does at the present time, while rerouting 0 .171 acres into the front parking lot drainage system, by removing the existing pavement and repaving this area. There is a o. 8781 acre tract that fronts on Tex as Avenue, / which is presently paved and sheet flows to Tex as Avenue. This area will be repaved. This tract has a depth of 225 feet back from the Texa.s Avenue R . 0 . w. will be allowed to continue to sheet flow to Texas Avenue. 9 Year 2 5 10 25 50 100 Year 2 5 10 25 50 100 FLOW FROM AREAS THAT CONTINUE TO DRAIN AS THEY DO AT PRESENT c i A (to Texas) A (to Lincoln) Q (Tex.) Q (Linc.) 0 .75 6 .3 0.8781 ac. 0.8 861 ac. 4.15 cfs 4 .19 cf s 7.7 5 -. 07 5.12 8.3 5.47 5 .52 / 9 .8 6 .45 6.51 11.1 7 .31 7.38 12.6 8.30 8 .37 FLOW FROM AREAS THAT WILL BE REROUTED TO PROJECT c i A (from Linc.) Q (Ci) 0.75 6.3 0.1710 ac 0.81 cf s 7.7 0.99 8.3 1 .06 9.8 1. 26 11.1 1.42 12.6 1 .62 The proposed parking lot in front o f the shopping center will have nine separate detention ponds, all with the same low point elevati o n at inlets and wi_ll b e drained by pipes to the existing inlet on Lincoln Avenue. All the runoff on the proposed buildings and behind the b uildings will be subject to a detention p o nd to be constructed adjacent to the northeasterly property line . b. The off-site runoff from the undeveloped property to the northeast , will remain the same. Th e total discharge from the front parking lot and the discharg e from the detention pond will be equal to the runoff which occurs at the present time, plus the drainage that has been rerouted from the existing paved area being repaved . The runoff from the off-site properties that flow across this project at the present time have been rerouted through the subject property so as not to affect the drainage system of the proposed development . c. The development is broken into five areas. Pre- d eveloprnent con s ists of Area A (the 707 Center). Area B (the property being developed),and E (the undeve l oped land on the northeast) . Area B is further divided into Area C and Area D . Area C is the raw land in front o f the proposed shopping center buildings that does not have existing pavement on it . Area D is the raw land that has the proposed buildings, the rear parking lot and pond on it . 10 I n.lL. Qi, ~~ *~~-~~-;a 7 The post development consists of rea C (same as above), Area ~· C1 (that portion of the pavemen that is in the parking lot '1 behind Red Lobster which has een rerouted to the front parking lot system, and C2 (0.0955 acres that has been ~If~ rerouted to drains to Red Lobster driveway) and Area D (the o~ same above). These areas are marked on the accompanying maps . ~ Unit Hydrographs and Flood Completed Hydrographs were prepared for each analysis area and combined where appropriate. The various storms were routed through the detention ponds. ~ PRE-DEVELOPMENT RUNOFF -UNDEVELOPED AREA C ~C,z_ Year c i A Q t~ .\u 2 0 .40 6.3 2 .9024 ac 7 . 31 cf s 5 7.7 8.94 ~ 10 8.3 9 .64 25 9.8 11. 38 50 11.1 12.89 100 12.6 14.63 PRE-DEVELOPMENT RUNOFF -UNDEVELOPED AREA D Year c i A Q 2 0.35 6.3 4.2927 ac 9.47 cf s 5 7.7 11.57 10 8.3 12.47 25 9.8 14.72 50 11.1 16.58 100 12 .6 18.93 PRE-DEVELOPMENT -PRE-DEVELOPMENT RUNOFF -AREA C TOTAL Year Area c AREA C1 AREA TOTAL AREA c 2 7.31 cf s 0 .81 cf s 8.12 cf s 5 8 .94 0.99 9 .93 10 9.64 1. 06 10.70 25 11.38 1.26 12.64 50 12.89 1.42 14.31 100 14 .63 1. 62 16.25 11 Soil Conservation Service, Technical Release no. 55 Q (inches) = (P -0.2 8)2 I (P + 0.8 S) s = (1,000 I CN) -10 PRE-DEVELOPMENT VOLUME FOR AREA c Year p CN Q(inches) Area 43560/12 Volume 2 4.5 75 2.05 x 2.9024 x 3630 = 21598 cf 5 6.2 3.46 36454 10 7.4 4.51 47516 / 25 8.8 S.77 60791 so 9.8 6.69 70484 100 11. 0 7 .82 82389 PRE-DEVELOPMENT VOLUME FOR AREA D Year p CN Q Area Volume 2 4.5 75 2.05 4.2927 31944 cf 5 6.2 3.46 S3915 10 7.4 4.Sl 70277 25 8.8 5.77 89911 so 9.8 6 .69 1.04246 100 11. 0 7.82 l21377 POST-DEVELOPMENT RUNOFF -DEVELOPED AREA Year i A Q (cf s) ~ 2.9 * ac 2 6 .3 * 14. 07 cf s 5 7 .7 ~. 01'?'-/-o-.c, it 17.20 10 8.3 --;f 18.54 11 2S 9 .8 #' 21.89 50 11.1 ;¥24.79 100 12 .6 Jt28.14 Soil Conservation Service, Technical Release no . SS Q (inches) (P -0.2 8)2 I (P + 0.8 S) s = (1,000 I CN) 10 12 POST-DEVELOPMENT VOLUME FOR AREA C TOTAL Year P CN Q(INCHES) Area 4356D/12 3.82 x ~ 3630 5.50 ~ 2 4.5 5 6.2 94 10 7.4 6.69 25 8.8 8.08 50 9.8 9.07 100 11.0 10 .27 POST-DEVELOPMENT TIME Year 2 5 ~ 59454 10 * 7231 7 25 .f 87343 50 '# 98045 10 / 111016 ..;. 14. 0 '117.20 f 18. 54 A 21. 89 t 24 . 79 i 28 .1 47 .41 47.30 POST-DEVELOPMENT RUNOFF DEVELOPED AREA A (ac) Q (cfs ) 2 6.3 4.2927 ac 17.58 cf s 5 7 .7 19.83 - 10 8.3 21.38 25 9.8 25.24 50 11 .1 28.59 100 12.6 32.45 Post-DEVELOPMENT VOLUME FOR AREA D Year p CN Q Area Volume 2 4.5 91 3 .50 4.2927 54538 cf 5 6.2 5.15 80249 10 7 .4 6 .33 98637 25 8.8 7.72 120296 so 9.8 8 .71 135723 100 11 .0 9 .90 154f2 6 6 13 \J \ D ':f. 41293 )I 59454 'JF 72317 I 87343 ~ 98045 t 111016 /_r ~ ) J 11 ~<J / POST-DEVELOPMENT TIME TO PEAK FOR AREA D Year Vol Q (cfs) Vol/(1 .39 x Q x 6 0) = Tp (min) 2 54538 17.58 37.20 5 80249 19 .83 48.52 10 98637 21.38 55 .32 25 120296 25.24 57 .. 15 50 135723 28.59 56 .92 iOO 154266 32.45 56.98 d . The drainage patterns are as follows ; 1) the off-site runoff has been rerouted to remove them from the design consideration for this project, 2) portions of existing pavement runoff will be allowed to flow to Texas Ave . and Lincoln Ave . as it does at present, which removes it from the design considerations for this project, with the remainder being included in the front parking lot system, 3) the 225' adjacent to Texas Ave. that is being redeveloped as part of the parking for this project will be allowed to sheet flow to Texas Ave. which is the direction of its runoff at the present time . 4) the runoff from the front parking lo t will be detained in nine separate ponds on the pavement and piped to a junction box in front of the e x isting inlet on Lincoln Avenue, 5) the building and back parking lot runoffs will be detained in a detention pond located adjacent to the northeast property line, and 6) the off-site runoff from the adjoining undeveloped property on the northeast side of the project will be intercepted by a back-slope trench and taken into the system by use of an open sided inlet which will allow a portion of the flow to enter Lincoln Ave. without causing a strain on the drainage capacity of the existing pavement. 14 2. Specific Details : a. The drainage problems encountered in the drainage design of this project were: 1) incorporating the existing paving into the proposed new front parking lot. The existing pavement determined the elevations in the new parking lot and the elevations of all the other items in the developments . 2) determining the best method of handling the runoff from the off-site prope_rties. To simplify the design consideration, these runoffs were rerouted around the internal drainage systems . 3) To prevent a system overload by including all of the runoff that may occur during a 100 year storm, the inlet at the end of the back-slope trench i s designed to allow a portion of the runoff to pass around the open sided inlet and flow into the gutter of Lincoln Ave. which will not adversely affect the street drainage characteristics . b . Detention solution encountered the following problems ; 1} The location and arrangement of the back -slope trench caused a problem in the layout of the detention pond. To allow enough room to place the back-slope trench on the proposed project property, the width of the rear parking lot was reduced. 2) The use of a detention area in the front parking lot was used, because of the restrict i ons imposed on the rear detention pond, mentioned above. The use of detention ponds on the front parking lot required the removal of a portion of the existing pavement to provide an adequate amount of storage. c. The arrangement of the inlets and junction box es in the system will facilitate easy access for maintenance . The only problem that may occur is the size of the pipe that leaves the existing inlet on Lincoln . CONCLUSIONS : 1 . It is our opinion that all of the Standards of the City of College Station Drainage Policy and Design Standards have been me t. 2. The effectiveness of the proposed drainage design will not allow any additional damage from storm water flows that do not exist at the present time .. 15 3. The proposed drainage system was designed using the 100-year storm information furnished by the City of College Station . Therefore, the development of this project will not change the runoff in the secondary system from what is experienced at present . REFERENCES : All criteria and technical information followed the guide lines of the City of College Station Drainage Policy and Design Standards and prepared using the Eagle Point software. APPENDICES: 1. Hydrologic Computations 2. a. Land use for the 707 Center was Business/Commercial and the land use for the undeveloped property to the northeast of the project was Natural Grasslands. b. Storm water runoff (peak 100-year discharge) for; 1) the 707 Center was determined to be 30 .38 cfs 2) the pre-development raw land portion runoff of the project was determined to be 35.18 cfs 3) the undeveloped off-site property to the northeast was determined to 13.01 cfs cf s 4) post developm .nt run-off for the front parking lot was determined to b ~ 28.14 · fs 5) detention pon ~ m:x.crnum discharge ;f:' 6) detention in parking lot max. disch~e 21.80 cfs. ------- c. The ~-veloped 100 year runoff for Area c and D is 35.18 cfs and th post development discharge for Area C and Area Dis 35.18 cf . Therefore, the project does not increase the total runoff that presently occurs . -1::1-l.ic a. There are no culverts in this project. 16 b. Storm Sewer Capacities 1) 2) Pipes in front parking lot a) 18 11 capacity = 8.79 cf s b) 24 11 capacity = 12.59 cfs c) 30" capacity = 50.19 cf s d) 36" outfall = 39 .58 cfs : e) 24 II from 707 Center; cap . = 18.18 cf s Pipes from the detention pond and back-slope trench a) 12" capacity = 9 .22 cfs; will carry 9.0 cfs the remaining 4 . 01 cfs (for 100-yr storm) wi ll be discharged to Lincoln Ave . b) 30" capacity= 39 .95 cfs c. Street Capacity: Lincoln Ave.; Yo= 7", Sp= 19', slope= 1.33% Q (half section) = 20.0 cfs capacity from City of College Station topo . map, the area being drained by this reach of Lincoln Ave. is 3.75 Acres Time of concentration = 300 ft. at 1 fps = 5 min + 900 ft . at 2 fps= 7.5 min Total Tc = 13 .5 mi n . Intensity for (25-yr storm) = 8.3 in/hr Runoff coefficient; Medium density residential c = 0.55 Runoff for Lincoln Ave .= 0.55 x 8.3 x 3.75 = 17.12 cfs d . Storm Inlet Capacity: 1) Inlets in front parking lot are all 2 foot square grate top inlet. Open Area is 75% of 4 s .f. = 3 s.f. Ag= 2.4 -25i (3) 2 .25 s.£.; aver . Q = 3 .1 7 cfs Q/Ag = 3.17 I 2.25 = 1.41: from Fig . V-2 y = 10" 2) Inlet for back-slope trench is a box with three side open and a 4" X 3' X 3' reinforced concrete lid. Length of openings = 3 x 2' = 6' Q (@height = 8") = 6' x 1.5 cfs/ft. = 9 .0 cfs The remaining 5.71 cfs (for 10 0 -yr runoff ) will be discharged to Lincoln Ave. gutter. 17 e . Open Channel design : Back-slope trench Q (100-yr runoff) = 13.01 cfs Trapezoidal earthen trench with 2: 1 . side slopes Bottom= 2 .0' Height = 1 .12' p = 2 + 2(2 .50') = 7 .00' A= 2(1 .12) + 2(2 .24 X 1 .12)/2 = 4 .75 s.f . R = A/ P = 0 . 6 7 8 5 ; R 213 = 0 . 7 71 n ::: o . 02 s = 0.25%: sU2 = 0.05 v = 1. 486/n X R213 X S 1 1 2 v = 74 .3 X 0.771 x 0.05 = 2.86 fps Q = 4 .75 X 2 .86 = 13.59 cfs > 13.01 cfs Therefore the height will be somewhat less than 1 .15 ' FINAL DRAINAGE REPORT DRAWING CONTENTS: 1. Sheet #1 -General Location Map 2. Sheet #2 -Floodplain Information 3 . Sheet #3 -Drainage Plan Map I hereby certify that this report for the drainage design of the Lonestar Pavilion Shopping Center development was prepared by me or under my supervision in accordance with the provisions of the City of Co l lege Station Drai n age Po l icy and Design Standards for the owners thereof . Q.r;ikW (kl9z Registered Professional Engineer State of Texas No. 26383 18 101 CENTER EXISTING 1R-Rl'P / ~,,.,,.r :: / -----· 1 .~·/ TCJ29..70 GJ28.20 -.... .. )./ WAI()< ELEV. ":i) ,...1C.J29 2l CJ2&.7) '"'-.... -. _,, ... ~y .. / q ~~~ ~ __ ,.-..... --t-~--~ _ ~'·!E..• ~ ·~ ... w"' 120.02·•_1._02;...•_,. __ .. 1 _§ .l?lll.n l;L_ : 11: I ) I~ J2&•8 ( • '° N ' ~ ~(;' - --~~~-g~...._ l/__ • ,...~ f ,J 2'22 j;J I ./ JOIO •' .. '•'"-----<'"-1J4.12"•2.l7• IM.ET-2 1 ""S.•o ·~--12'e UO:ll llll--.....i'°9-11'-5~ :...------------.,. ---: ~lo) :.. •·-~ J6 211"• i"4h1 :; I -.... 21 7• 328 JO n · ,:,;:;:.: I cJ2s.:io I 326 .l! i.o ;;; 326 60..._ -~. '-I/ .... \ , l.;;.O'.:.:.~ __ ..,,. ... ---------.---------"'_,tt------,------tll""' ~ t ,~ I~ · --· re 27 .81 TCJ2• JO'L ..... LJ ~3l~~.:-)1 J3l!'oo'O I .... ~m~ b1~;~~ o , l'"-----i---c 1 Ja 0 0321.83 .. . I .... • I ~ ~,,,... \ i-+ -~ TYPE B INLET (TYP) ~ I -... ~ I ' ~... •5.3.,9. • •.oo>; • .,,,.,, n )606' • 0_., · .. fl..,;!_____ ~[....__ _ -:-i J .l0.•1 ·• 2.09 .s ~1.11·• J.?o .. 1--4--~JJ2•.101 I ~ ~ -------r . 31719 ~--=-~~ IBJ'e rns J S~>9 ·ce1.•09< ~ ~~~ ,..... 00 ::t :;u n. 320.IS I o ::I ~cJJ2~• ..... , I ; c'c3J2'•'.oo-~ g lC.lH .~ TCJ2~~ ~ I .. /~ ~~~~~er ~ 11 G324 .oo cJ2~ ... o '° ~ 8 ~ '\ 0 .. If !\ +-1!>3.19'. I.~ ----- 198 00 -----. ····-·--·------· I :!J I 8 1CJ2&.70 CJ26.20 l27.2• TC3:H .&J CJ21.lJ ... ---·-,.------~--.. :....i ~3~!'oo~ 0 ••so•~oos l N ----~ •,.!.l.02 "---' .. 1'Cl24.'0 (1)2 .. 00 I 40.lt'92.07~ ---,it ~ 0 • ... =·-9_ .• ,.2· .. ·-·-~-~_:_;_'°~(1~1 NET-I R1w JZJ.17 n. 31 8.66 n M VT C) b Q. ~.s,. ..,_ ________________ ..,."-¢ RED L065TE~ PAVEMENT PARKING ISLANDS :D PAVED TO iG PAVEMENT I l?t.J Gt I r = ~ l!o J2~.79 s I "' 5 :g ~s !i a~ ~ ,.3 11.~cr 11.DO' I). n:zo•• ~.oox :g .-J2S..1t ~ "' TP J26,10 -12/20/1996 15:30 713-796-0623 ~19,1"6 Collep Stdcm/A.B./Limited hrenmp A Delaware Limited Pftm]Dp Attn: Mr. Charles W. Shem 1325 La Ccncha lbla1m, Taat 1705~ SHEARS COMPANIES PAGE 04 Jt is undarstcod and nnnually t.greed that Calles• Sfldorl!AB./Limited Pumenhip. a DclaWlll I.mted Pannership, wW pwcipue in me conswcdon cf a. StDmi chin from me aub inlet Jo;1ted ai 1be inte:section ctUneem Awnue aad Fosm Awnua 10 die storm drain system 1«ued within me Texas Avenue riJiu-cf-way . The Limited Partnership agrees 10 Snaneially paftigpate ift an amount mt equals !ft>' percent (SO'/o) of the total ccmtnl~ eo&t up 10 a maximum often tho~and dollus (Sl0,000). ~L KcuM.Lm~ Collogc Station/ A B./Limitcd Partnership, a Delaware limited partnership . By: A.B . Operations. Inc ., a Delaware Corporation . lts~e7 Br_)ft;}_~ Name : J<l~~ · W1 nq 0 Its: S'r . V. t/ Datt: ofSisziarure:y-2 1/-96 FAX TRANSMISSION WILSON/ZETIY/ASSOCIATES 3100 W il crest , Suite 325 Houston , Texas 77042 713/952-8600 FAX 713/952-8610 /) No . of Pages Inc l. This Page : Z ProjectNo .: 9~9 , Project Name~~ , %u, ~ Com p any: Attn : Fax Number: From : Date : t/12 9/11t tj_-~ t.f_V, i)au<.s ff.; ~°'--/'/llu/zA-:a./ 12-d-1/J-9 ~ I -1'21)011,96 15 : 30 713-796-0623 CoDep Stdcm/A.B.II.Jmited Parcnership A Delawan Limitld PntnlDp Attn: Mr. CharlM W. Sbcml 132' I.& Ccncha ~T..u'7'10!.C SHEARS COMPANIES PAGE 0 4 lt is undamaod md nnmW1y -.reed that Collea• S~AB./Limited Parm«lhip, a DclaWll'I Limited Pannership, will pvticipue in !he cor.suuciion of a. smnn chin ~m me ~ inlct loc:ated ai 1he i:tteMCtion o!Lineom Awnue and Fosm Avemia 10 the storm dlain s)'ltem kxued Vw'iihin me Texas Aw.ai.e riJbt~f-way. the Limitad Parmership agrees to Snaneially parti;;ipate in an amount me equals My percent (SO%) of 1be total ~en COit up to a maximwn of ten thouslZSd dollars ($10,000). !J:L KmrM.Lua~ City &peer Ji A Date ci Signature: / .4 I 'I '-' rr College Station/ AB./Limitcd Partnership, a Delaware limited partnership . By : A.B. Operations. Inc., a Delaware Corporation . Its~7 Br~4o Name: R~~~ · W1 V\'1 Q Its:~. rf Date of Siprure: fl -2 1l -9 6 - February 28, 1997 Dear Operator: Your Notice of Intent (NOI) for the facility noted below has been processed by the U.S. Environmental Protection Agency. This facility is authorized to discharge storm water associated with construction activity under the terms and conditions imposed by EPA's NPDES storm water baseline construction general permit issued for use in the state of Texas. Your facility's NPDES baseline construction storm water general permit number is TXR10Y734. EPA's storm water baseline construction general permit requires certain storm water pollution prevention arid control measures. Among the conditions and requirements of this permit, you must prepare and implement a pollution prevention plan (PPP) that is tailored to your construction site . Enclosed is an insert explaining how you may obtain a summary: guidance document designed to assist you in the development and implementation of your PPP. The summary is organized according to the phases of the pollution prevention planning process and contains a set of worksheets and an example of a pollution prevention plan .. As a facility authorized to discharge under this storm water baseline construction general permit, all terms and co\lditions must be ~omplied with to maintain coverage and avoid possible penalties. ~". ~·· FACILITY: Lo~e Star Pavilion 715 S Texas Ave College Station, TX 77840- OPERATOR: Tribble & Stephens Co 10610 Haddington Dr Houston TX 77043- ·' • [ ] 1061 O Haddington Houston, TX 77043 (713) 465-8550 [ J [ ] [ ] m Tribble & Stephens Co . • Transmittal Letter Mail 4-Hour ROUTING ------2-Hour _____ _ 1-Hour ------ P ick-Up ------ Spec ial p J4-,,A/ Jd To: c 1t=i1 ofl ea/111 <'/e :5t?tt10,,U DAT E: /p -6 -7 7 I I , --<o-----"---'----------- 1/ 0 I 'TZ:Xif-5' ft;J~A/t/-C JOB: ~ 5 ~/'~ Co//-ec1 < <~t?.,,u Y-J< I 7 7/2 '/Z- ATTENTION: f;T-<' vr: ,tfi:! fflt'J'C'eL- We are sending you: Herewith(~ Under separate cover( ) Copies These are: Remarks: I Description ' =3 acJ 1=/f Cd//.e y -e ,::;r1tDaAJ ( ) for approval. Please return _copies/prints. ( ) returned approved. ( ) returned approved as noted . ( ) returned disapproved , resubmit. ( ) for files and use on job. (~tation only. /.', ( ;/!-!'n<. yo v I( J I-< 5 L,x . ------------------------------ Copies to: :::t-V';-4e> A) S/I e_// ~ yYJ 6 /(_!) uJ ,,u f; )L- TRIBB L ~CO. . By: ~ Slro'94 z: 4 09 776 6699 MCC LU RE E NGR INC p. 0 1 McCLURE ENGINEEF October 3, 1996 + t L ~ .' Lo-"1€ -S!"f're_ '""?A\.( IL I o A.f "'bc-V ~/Y\ /i Mr. Thomas Eikel . P .E . EIK.EL ENGINEERING 3100 Wilcrest, Suite 325 Houston, TX 77042 RE: PROPOSED SEWER LINES LONE STAR PAVILION PROJECT Dear Mr . Eike!: I have reviewed the proposed sewer alignments for the Lone Star Pavilion with respect to the planned lines for City of College Station Eastgate Sewer Rehabilitation project and I submit the following for your information and design : 1. A 12-inch sewer line with a minimum 15 ' wide public utility easement placed approximately parallel to and 72 .6' southwest oft he northeast property line of the Lone Star Pavilion is satisfactory . The sewer line should be terminated with a manhole placed IO' from your northwest property line and with a Flowline (out) = 316 .25 . (Please see attached sketch and Benchmark reference .) 2. New 15' and 20' wide public utility easements along the northwest property line are also needed to accommodate another future sewer line . Should you have any questions or need additional information, please advise . Very tru ly yours , JJM/mlm attachment 1722 Broadmoor, Suite 210 • Bryan , Texas 77802 • (409) 776-6700 • FAX (409) 776-6699 -i ~ x 0 "' ~ c · e>o ~ o_, <'o C> 10 /03/9 6 1 6 :2 0 Live Oak ~o. «+ ~· o_, <o .,., C> z 409 77 6 6699 IL I I J ------------------------------------=il o I .. :, ... ·: ''''''f '''_,,,f ' .. , ' .····• .· .. ~. ~ .. Lincoln Dr. \ ri o'? I 0 ·1: ~ Ch ~ ::> C =tO .... 0 :J • 3 [ zO VI. .... ~-?>· 0 ~Co~ :J'"---~ Ash ~--­., r 0 ::> (b (/) ~ ,... 0 o., ""\ 0 -u (/) 0 (b $.a. 0 ::> MCC LU RE ENGR I NC P.02 TO: Accounting Department City of College Station P.O . Box 9960 Colle e Station , Texas 77842 Statement Joe Orr, Inc. Surveyors & E ngineers 2167 Post Oak Circle College Station, TX 77845 < (409) 690-3378 ~ \;\J ~ JY fjj \~ ATTN: eronica Morgan Engineering Departmemt eti:!nlii::1ii¥!1t:P:r:12ng::m1:1i.xin2n.::1t91~m.::;;;:: ::::::::me12,te.J1!2ni.!:;gnij!uigrl::::rn:~m::::::::::m::::::1::1:::::::::::=::::::i1i:rn::::;::::: .~cour~T ING Sales Tax Total Due 7-Jan-97 WILSON/ZETTY /FOSTER/TIPPS ARCIDTECTS/PLANNERS/INTERIOR DESIGNERS, L.L.C. 3100 WILCREST, SUITE 325 HOUSTON, TEXAS 77042 (713)952-8600 PROJECT: Lol-4fi S 7A R.. Pl\ Vi );~ Ct:>\\ etJJ <1-S "lt::t -f 1 CM, T ;x SHIP TO: c;, T r;;Vf5 N 0 lM 112.'G= c 1 /11 'f) i-Co t ( E'f1 ('° s -f .?t°h CW) t Jot -re~S Me . Cb u e'?P s+~ -4t l04r T )(. { 7 gq L TELEPHONE: WE HEREBY TRANSMIT THE FOLLOWING: ()DRAWINGS DATED: I /w {CJ ] ()BID SET(S) () w/ INSTRUCTIONS TO BIDDERS ()REVISED DWGS. FOR YOUR: ARCHITECT'S PROJECT NO: q /:,-6 S"') DA TE: 1// <j- VIA: () * () () REGULAR MAIL OVERNIGHT DELIVERY HAND DELIVERED COURIER SERVICE ( ) RUSH ( ) REGULAR HOLD FOR PICK UP H enclosures are not as noted please inform us immediately ()~~~~~~~~~~~ ()~----------() __________ _ ~APPROVAL () FOR SIGNATURE ()INFORMATION ()RECORD ()FORWARD AS NOTED () REVIEW AND COMMENT ()OTHER ____________ ~ ME SSAGE/COMMENTS: -------------------- \::;\l\.C\&->$ e J a. vr :tl1 re t"" C'e>:ft<95 a-f ~~-f: ruc ftcth Dva.w 1 vi121 s s 1cg_..e. f: ~ -1 • c -'-. c-3 c_ -r:, . c. -7 c -B I i I , 7 I a.A so r wo Ce;>\'?' es o--J-~ V-ev1 s~d_ F 1ttu1< ( D va 1t11 t1 i?( e f2.e__ f O t:f COPIES TO : (WITH ENCLOSURES) () () () () ORD E RED BY : () OWNER/CLIENT () ----------- () CONTRACTOR () __________ _ PACKAGE PREPARED BY: --Z-:£ · NU MBER OF PRINTS: () BILLABLE TO CLIENT () INVOICE E NCLOSED () OFFICE EXP EN SE () ------- T RAN S2.SA.M WILSON/ZETTY/ASSOCIATES, INC. ARCHITECTS • ----• PLANNERS December 30, 1996 City of College Station Engineering Division 1101 Texas Ave. College Station, Texas 77842-0960 ATTENTION: Mr . Steve Homeyer RE : Lonestar Pavilion De ar Mr. Ho me y ~~; Included here wi t h , are the copies of the revised construction pl ans .and two copie s of t h e Fina l Drainage Engineering Repo r t . We chang ed the size of the deten t ion pond and the detention area in the front parking lot. We added cross- sections for the front parking lot and a storm water pol lution prevention plan for the ·Lonestar Pavilion project . Yours truly, /CH~P.E. 3100 WILCREST, SUITE 325 • HOUSTON, TEXAS 77042 (713) 952-8600 FAX TRANSMISSION WILSON/ZETTY/ASSOCIATES ,1, ~~~VJ; 3100 W1lcrest , Suite 325 ~~ "~tr -~ , Houston, Texas 77042 ~ ~ 1 7131952-8600 \~:lo v ' FAX 713/952-8610 ~ -Gv , -~ Project No .: q 665q Project Name: LoH<E 51~~ ~'-'lL-16~ SC. 0 f?~GA?c o.eec:r 1"3 w~de\/t::re ,~ J<e\ue~\('{Ct. IJZE.'lt~t:') C1'-'tL, ~cs. o .. HitLG ~'H:. +\. \~ 6d\ .... Company : Attn : Fax Number: From : Date : CrrLt df ~LW:1e 5-rAT\ON SH\~ \l~t..'t< LONE STAR PAVILION, COLLEGE STAION -DRAINAGE CALCULATION RUNOFFS FOR AREAS C & D EVENT Q CPR £ Q DPRE TOTAL PRE Q CPOS'!' Q Dposr TOTAL POS T 2 YEAR 8 .12 9.47 17.59 13 .62 17 .58 31.20 5 9 .93 11 .57 21.50 16.65 19.83 36.48 10 10.70 12.47 23.17 17 .94 21 .38 39.32 25 12.64 14 .72 27.36 21.18 25.24 46 .42 50 14.31 16.58 30 .89 24.00 28 .59 52.59 100 16.25 18.93 35.18 27.24 32.45 59.69 PROPOSED DISCHARGES EVENT PARKING LOT DETENTION POND TOTALS 2 YEAR 10.73 6.86 17.59 5 13.11 8.39 21.50 10 14.13 9 .04 23.17 25 16.69 10.67 27.36 50 18.84 12 .05 30.89 100 21.52 13.66 35 .18 REQUIRED PARKING LOT DETENTION VOL = 1/2 X 2 TP X 60 X (Q posr -OorsCH.) EVENT Owsr -DISCH . = DIFF. X TP X 60 = REQUIRED VOL. ELEV. 2 13 .62 10 .73 2.89 35.19 6101 .9 C .F. 323.36 5 16 .65 13.11 3.54 41.44 8801 .8 323.53 10 17 .94 14 .13 3.81 46.78 10693 .9 323.65 25 21 .1 8 16.69 4.49 47.86 12893.5 323 .79 50 24 .00 18.84 5 .16 47.41 14678.1 323.90 100 37.24 21 .52 5.72 47.30 16233 .3 32 4.00 (ACTUAL 16251.22) ( 1) 2 YEAR 100 YEAR PARKING LOT OUT FALL CALCULATIONS Q = 10.73; ELEV . = 323.36; FL ELEV . = 318 .04 12 11 RESTRICTER PIPE -FL ELEV. = 318 .04 TOP ELEV. = 319.04 h = 323.36 -319.04 = 4 .32' 0 = Ca (2gh) 1 12 = 0. 82 X . 785 X 16. 67 Q = 21.52; ELEV. 324 .00 h 1 = 324 .00 -319.04 = 4.96' 0 1 =Ca (2gh)112 = 0.82 X .785 X 17 .86 10 .73 OK 11 .50 WEIR h 2 = 324.00 -323.36 = 0.64' 0 2 = 3.367 X B (h)312 = 3.367 X 5.81' X (0 .64)312 10.02 OToT AL = 11 . 5 0 + 10 . 0 2 = 21 . 5 2 0 K FLOW OVER WEIR PLUS FLOW THROUGH RESTRICTER PIPE ELEVATION O roTAL t ·-~c~r 324,lJO 323.5 11.94 W'ElR.. ----···v ~ i3, 3G • ~ s.&\• ->I 323.6 13.33 323.7 15 .02 323.8 16.97 e :~ __ : .... l!~.~4 323.9 19.14 ____ plJ~o~ ( 2) '. The Detention Pond was lengthen 14' which increases the volumes that were used in the December 26, 1996 report . INCREMENTAL VOLUMES OF THE DETENTION PO ND ELEVATION VOLUME 32 1. 50 322 .00 322.50 323.00 323 .50 324.00 324 .50 325 .00 325.50 326 .00 326 .5 425 CF 2479 5284 8983 13552 19208 26084 34119 43236 53358 64407 REQUIRED DETENTION POND VOL . = 1/2 X 2TP X 60 X (Q p0 sr -Oor scH.) EVENT Qf.'osr -DISCH . = DIFF . X TP X 6 0 = REQUIRED VOL . ELEV. 2 5 10 25 50 100 2 YEAR 17 .58 6 .86 10 .72 37 .20 23927 C .F . 324 .34 19 .83 8 .39 11.44 48.52 3330 4 324 .95 21. 38 9.04 12 .34 55.32 40958 325 .38 25 .24 10 .67 14.57 57 .15 49960 325 .83 28.59 12.05 16 .~4 56.92 56487 326.14 32 .45 13.66 18.79 56.98 64239 32 6.50 (ACTUAL 6 4 40) DETENTION POND OUT FALL CALCULATIONS Q = 6 .86 ; ELEV . = 325.34; FL ELEV . = 321 .23 1 .0' HIGH X 0 .716' WIDE RESTRICTER OPENING FL ELEV . = 321.23 TOP ELEV .= 322 .23 h = 325.34 -322.23 2 .11' Q = Ca ( 2 g h) 1 1 2 = 0 . 8 2 X . 716 X 11 . 6 5 = 6 . 8 4 0 K (3) ' . .. 100 YEAR Q = 13.66; ELEV. 326.50 h 1 = 326.50 -322 .23 = 4.27' 0 1 = Ca ( 2gh) 1 /2 = 0.82 x .716 x 16 .57 = 9 .73 WEIR h ; = 326 .50 -324.85 = 1.65' 3.367 X B (h)31 2 3.367 x .581' x (1.65)3 1 2 = 3.93 O r oTAL = 9 . 73 + 3. 93 = 13. 66 OK FLOW OVER WEIR PLUS FLOW THROUGH RESTRICTER OPENING EVENT ELEVATION 5 YEAR 324.95 7 .88 < 8.39 OK 10 325.38 9.07 > 9.04 OK 25 325.83 10.70 > 10.67 OK 50 326 .14 12.03 < 12.05 OK ,,,-.. W~ll'i. ~"2.C,, So Jtf . ·-., . .. . . '2,2.~·tS 158• £0 -l J, 'l / 'Z. 1. ;-i\1"1.] , ,, " ( 4) DEVELOPMENT PERMIT PERMIT NO . 410 LONE STAR PAVILION FOR AREAS OUTSIDE THE SPECIAL FLOOD HAZARD AREA RE: CHAPTER 13 OF THE COLLEGE STATION CITY CODE SITE LEGAL DESCRIPTION: Tracts 1, 2, 3, 4, C, D and E, D .A. Smith Subdivision SITE ADDRESS: Not Addressed OWNER: Shears Interests Attn: Charles Shears 1325 La Concha Houston, Texas 77054 (713)796-1005 DRAINAGE BASIN: Wolf Pen Creek Tributary "C" TYPE OF DEVELOPMENT: This permit is valid for site construction as shown on the approved plans. The Contractor SHALL NOT begin construction within the existing channel that bisects the subject property until all drainage issues are resolved as identified in the Letter of Agreement dated December 5, 1996. Contractor shall prevent silt and debris from leaving the site in accordance with the City of College Station Drainage Policy and Design Criteria Owner and/or contractor shall be responsible for any damage to existing city streets or infrastructure due to heavy machinery and/or equipment. In accordance with Chapter 13 of the Code of Ordinances of the City of College Station, measures shall be taken to insure that debris from construction, erosion, and sedimentation shall not be deposited in city streets, or existing drainage facilities. I hereby grant this permit for development of an area outside the special flood hazard area All development shall be in accordance with the plans and specifications submitted to and approved by the City Engineer in the development permit application for the above named project and all f the codes and ordinances of the City of College Station that apply . IZ-l,-4<, Date M-6 -&jb Date Contractor Date I , __ _.. Figure XII Development Permit City of College Station, Texas Site Legal Description : Tracts 1, 2, 3 , 4 C, D, E Site Owner : Shears Interest Architect/ Engineer : Thomas Ei kel Contractor : Tri bb 1 e & Stevens Date Application Filed : November 7, 1996. DA.Smith Subdivision Vol .49 Pg. 106 of Brazos County Address : 1325 La Concha Houston, Texas 77054 Jclephone: 713/ 796-1005 Address: 3100 Wi 1 crest #325 Houston, TX 77042 Telephone No : 713/ 952-8600 Address10610 Haddington Dr. Houston,Tx 77043 Telephone No :713 / 465, 8550 Application is hereby made for the following development specific waterway alterations : Site Drainage -Lone ~tar Pavillion 9 ,2705 Acre ~. 81 Application Fee &l Signed Certifications ~ Drainage and erosion control plan, with supporting Draina ge Report two (2) copies each . ii Site and Construction Plans, with supporting Drainage Report two (2) copies each . ~ Other : Architectural Shell Plans ACK N OWLEDGMENTS : I, _C_ha_r_l_e_s_S_h_ea_r_s ______ __, design engineer/owner, hereby acknowledge or affirm that : The information and conclu si ons contained in the above plans and supporting documents comply with the current requirements of the City of College Station, Texas City Code, Chapter 13 and its associated Drainage Policy and Design Standards . As a condition of approval of this permit application , I agree to construct the improvements proposed in this application according to these documents and the requirements of Chapter 13 of the College · 1 y C Charles Shears Shears Interest ~:::;-----, Contractor Jeff Roberts .. • Figure XII Continued CERTIFICATIONS : (for proposed alterations within designated flood hazard areas .) A. I, Thomas E i k el certify that any nonresidential structure on or proposed to be on this site as part of this application is designated to prevent damage to the structure or its contents as a result of floodi fro the 100 year storm. November 7,1996. E Date B . I, Thomas Eikel certify that the finished floor elevation ofthe lowest floor, includ.ing any basement, of any residential structme, proposed as part of this application is at or above ·the base flood elevation established in the .latest Federal Insurance Administration Flood Hazard ~~aj, as amended. !"\~A A ~ _N_o_v_e_m_b_er~7~'~1_99_6_·~~~~~~~~ t~ Date C. i I, Thomas Eike l certify that the alterations or development covered by this p J nnit shall not diminish the flood-carrying capacity of the waterway adjoining or crossing this pennitted site and that such alterations or development are consistent with requirements of the City .of College Station City Code, Chapter 13 concerning encroachments of flood ways and of ~---.---~~~~~~ November 7, 1996. floodway fringes . !141 Engineer Date I , Thomas Eike l do certify that the proposed alterations do not raise the level of the 100 year flood above elevation established in the latest Federal Insurance Administration Flood 1 HAaz:rd S~ ,/")/l/l-L-~ November 7,1996. ~ Enki11eef" -D-a-te~~~~~~~~~~~~~~~ Conditions or comments as part of approval: ~~~~~~~~~~~~~~~~~~~- In accordance with Chapter 13 of the Code of Ordinances of the City of College Station, measures shall be taken to insure that debris from construction, erosion, and sedimentation shall not be deposited in city streets, or existing drainage facilities . I hereby grant this permit for development. All development shall be in accordance with the plans and specifications submitted to and approved by the City Engineer for the above named project. All of the applicable codes and ordinances of the City of College Station shall apply . 381 145 (,' ---~-~-+---,-1--. 19 1 rye THANKYOU n 6870 ZETTY-WILSON DEVELOPMENT CORPORATION PAY TO THE 3100 WILCREST , SUITE 325 952 -8600 HOUSTON, TEXAS 77042 ~l=l~/7~/~9~6 ___ 19_ 88 -1295 / 1130 ORDER OF ____ _.c_,...,· ty'-l'-...._o ..... f___._.Co .......... l ....,] eg....._..P__._S ...... t ..... a ..... t .... i ....... o .... n _________________ $ 400. 00 00 2 7 7. 511• ·,i!~CITY OF COLLEGE STATION ~ ~ ENGil'EERING DIVISION Post O ffice Box 9960 1101 Texas Avenue C ollege Station, Texas 77842-0960 (409 ) 764-35 70 September 13 , 1996 To: Thomas Eikel , P .E . RE: Lone Star Pavilion Drainage Report Upon review of the submitted drainage report, we found the document to be lacking some critical information . The submitted report consisted only of numbers and did not indicate where the drainage area was or how it was being modified . The report must contain information outlined in the City's Drainage Policy and Design Standards Manual . This section is located toward the back of the manual in Section XI, Drainage Plan Submittal Requirements . We also require that the report be bound . This binding can consist of a staple or anything that will ensure that pages do not get separated from the document. I am returning the drainage report dated August 28, 1996 without a review . We encourage a Preliminary Drainage Conference if the design engineer is unfamiliar with our design criteria . If you choose to take advantage of this conference , call (409)764-3570 to schedule an appointment. You can also contact me at this number if you have any questions or comments . Steve Homeye r Graduate Engin ee r ---- ------ ' I • ~ 0/ \--. From: To: Date: Subject: Deborah Grace KLAZA, VMORGAN 1/20/97 4:15pm Lone Star Pavilion Project -Reply -Reply Veronica FYI to you!! >>>Kent Laza 01/20/97 04:12pm >>> No. As part of an agreement with the deveolper to resolve some of the drainage issues, we agreed to hire Mayo to do this. Pay for it out of professional services in our Engineering Budget. >>> Deborah Grace 01/20/97 03:50pm >>> I have a statement from Joe Orr for $520.00 for Drainage Review. Veronica said this might be something that we want to bill back to the Developer. Please let me know.