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Home My WebLink AboutDrainage Report Regarding South Forl of Lick CreekDRAINAGE REPORT REGARDING EFFECTS ON THE SOUTH FORK OF LICK CREEK RESULTING FROM FULL DEVELOPMENT OF DOVE CROSSING SUBDIVISION COLLEGE STATION, TEXAS April 13, 2009 Prepared by: Civil Development, Ltd 2033 Harvey Mitchell Parkway South College Station, Texas 77840 (979) 764-7743 .. General Information and Background The Dove Crossing Subdivision encompasses an area of I 07 .76 acres on the south side of Graham Road west of SH 6 in College Station, Texas. It is bordered on the north by Graham Road, on the south by the South Fork of Lick Creek, on the west by two schools, and on the east by undeveloped property. At the present time, the site has been partially developed as single-family residential lots. Phase I of the subdivision began in 2005. Since that time Phases 2, 3, 4 and 8 have been built. These phases comprise approximately two- thirds of the entire site. Still remaining to be developed are Phases 5, 6, 7 and 9. Except for a small section of Phase 1 that drains to Graham Road, stormwater runoff from the Dove Crossing Subdivision site drains generally southward to the South Fork of Lick Creek. This natural channel is one of the regulated watercourses in College Station that is described in the B/CS Drainage Design Guidelines. It is the receiving stream for several major subdivisions in southern portions of the city and has been studied extensively over the last 10 years as development occurred. These previous studies were used in this analysis and will be referenced later in the report. The most recent Preliminary Plat of the Dove Crossing Subdivision was prepared in August, 2005 (Exhibit A Sheets 1 & 2). On that preliminary plat there is a note that states the following: 12. The storm water detention facilities for Phases JA , JB, JC, 2, 3, and 4 of this subdivision will be temporary detention ponds located within the limits of Phases 5, 6, 7, & 9 of the subdivision. The existing ponds on the property will be modified and utilized as temporary detention ponds. The temporary detention facilities will remain under the control of and be maintained by the developer until the permanent detention ponds are constructed. The permanent storm water detention facilities for the entire subdivision will be located in the 9.8-acre tract shown on this plat. The permanent detention facilities will be designed to meet the requirements of the City of College Station Drainage Policy and Design Standards. A Drainage Study will also be provided with the permanent facility design to show that the JOO-year flood elevations for the South Fork of Lick Creek are not increased by this development. As indicated in the note, the existing phases of the subdivision have been developed using temporary detention facilities. These facilities were designed to mitigate adverse stormwater impacts from the developed phases, and they are currently functioning as intended. The report that follows was prepared to address the development of all subsequent phases in the subdivision so that appropriate planning can be made regarding storm drain sizes and roadway locations. The need for this report has taken on a greater sense of urgency as a result of recent agreements between the developer and the City of College Station regarding the construction of Eagle Avenue through the site. This roadway lies on the southern end of the planned residential land use area, and it serves as a border between the residential lots and the natural vegetation found along the South Fork of Lick Creek. Construction of Eagle A venue is currently underway and, when completed, will provide improved traffic circulation for the new elementary school on the adjoining tract that is planned to open in August, 2009. Flood Hazard Information The South Fork of Lick Creek is not a FEMA regulated stream according to FEMA Panel No. 48041 C020 I- D. As a result, no property in the subdivision or in the adjoining subdivisions falls within the 100-year floodplain as defined by FEMA. The current version of the BCS Unified Stormwater Design Guidelines, as well as the previous controlling document referred to as the College Station Drainage Policy and Design Standards, both list the South Fork of Lick Creek as a regulated stream. These documents require that the finished floor of houses adjacent to the channel be raised to 3 feet above the base flood elevation associated with the ultimate basin development condition. In the absence of FEMA requirements, this local regulation was implemented to account for anticipated rises in water surface elevation as development in the drainage basin occurred. Generally, it appears that the regulation has been followed, although it is not clear what model was used to generate the flood elevations associated with the ultimate basin development condition. At this time, there are no known flooding issues within the basin. Development in the Drainage Basin of the South Fork of Lick Creek Over the past I 0 to 12 years, the drainage basin of the South Fork of Lick Creek has experienced some of the most intense development of any basin in College Station. Large subdivisions including Edelweiss Gartens, Alexandria, Westfield, Westfield Village, Cypress Meadow, and a portion of Shenandoah Subdivisions all fall within this drainage basin. Several smaller subdivisions also lie within the basin boundaries. It is estimated that approximately 90% of the basin has been or is currently under development. Exhibits B & C show the Pre-Development and Post-Development Drainage Area Maps that reflect the amount of development in the drainage basin. Hydrologic and Hydraulic Analysis As part of the stormwater analysis for this development, HEC-HMS and HEC-RAS computer models were prepared to study the effects on water surface elevation in the South Fork of Lick Creek. These models were built upon previous work by other engineers (McClure & Browne, Mitchell & Morgan), which begin at the upper reaches of the stream in the Edelweiss Gartens Subdivision near SH 40 and extended downstream to the confluence with the North Fork of Lick Creek. The models were adjusted to incorporate effects from the known detention ponds in these recently developed parts of the drainage basin. Additional survey data of stream cross-sections was added to more closely represent the actual field conditions through the stream segment affected by the Dove Crossing outfall. Table 1 provides a listing of the hydrologic modeling data, runoff coefficients and lag times used to determine runoff and flowrates in the HEC-HMS model, which was in turn used as input for the HEC-RAS model. Table 1 HEC HMS Modeling Data Used in the Dove Crossing Analysis Pre-and Post-Development Conditions i i : ! ······· -~!:~~---.J_~~ ml % Impervious Draina e Area (see Exhibits B & C) Acres Pre-Development Conditions IA 78.99 18 IC ID IE 3.1 3.2 4.1 4.2 4a 5 5a 5b 6 6a 6b 7 7a 8 8a Total 19.67 93.09 23.28 6.74 70.24 21.00 67.33 33.71 20.00 31 .63 21.52 12.12 37.63 41.73 61.80 11.54 81 .23 37.03 81.09 854.98 S . Miles 0.1234 0.0307 0.1455 0.0364 0.0 105 0.1098 0.0328 0.1052 0.0527 0.03 13 0.0494 0.0336 0.0189 0.0629 0.0652 0.0996 0.0180 0.1239 0.0579 0.1267 1.3359 86 86 85 85 82 82 82 77 84 84 82 84 75 75 84 75 84 80 75 84 49 48 42 45 29 29 21 10 38 38 30 38 0 0 38 52 38 20 0 38 Post-Development Conditions (onl)' the areas noted below changed from those above) L ours 0.6 1 0.34 0.59 0.46 0.2 1 0.64 0.10 0.70 0.4 1 0.40 0.40 0.40 0.40 0.78 0.38 0.50 0.40 0.39 0.87 0.31 3.2 * I 22.35 I 0.0349 1. 82 1. 21 I 0.10 5 * 34.14 0.0533 82 ' 30 0.40 5b* 12 .18 0.0190 15 I o 0.40 6 37.63 0.0588 75 52 0.50 6b 68.46 0.0652 84 38 0.38 7 * 9.43 0.0147 84 38 0.40 *Note: These drainage areas involve minor changes in area resulting from grading patterns in the vicinity of the Dove Crossing Subdivision. No other parameters in the model were changed in these drainage areas. A number of scenarios were analyzed using steady-state modeling techniques to determine the appropriate size and location of detention ponds that could offset the increase in water surface elevations resulting from the Dove Crossing Subdivision. None of these scenarios were successful in reducing water surface elevations to pre-development conditions. In all cases there were small increases in surface elevations, even with the use of very large ponds. To address this issue, the engineering firm of Mitchell and Morgan Engineers and Constructors were retained to analyze the system using the unsteady flow option in HEC-RAS. Following several iterations, a solution was found using the pond shown in Exhibit D. This design is referred to as a side-channel weir detention pond and it is used to control the maximum water surface elevation in larger channels. Under this design, water from the development outfalls directly into the stream and the pond stays mostly empty until such a time that the water surface elevation in the stream reaches the weir height and it begins to flow into the pond. The pond is designed to hold sufficient volume so that the maximum water surface elevation in the stream does not exceed the desired level. Once peak flows in the stream pass and the surface level begins to recede, water inside the pond drains out slowly through a small outlet pipe (see note). The full report on this pond by Mitchell and Morgan is provided in Appendix 1. Their report includes an exhibit showing locations of all cross-sections in the HEC-RAS model. It is referred to as Exhibit 2 in the Mitchell and Morgan report, but it is included as Exhibit E in this document. A comparison of Pre-and Post-development water surface elevations at each cross-section are shown in Table 2. Note that this is a partial listing of cross sections included in the HEC-RAS model beginning a short distance upstream of the Dove Crossing Subdivision . A full listing of all output from the HEC-RAS model is shown in Exhibit F. Note : Th e outlet pipe allows a controlled amount of water to flow into the pond any time that the water surface levels in the stream exceed itsjlowline elevation. During highflow situations, some amount of water will be in the pond before it begins to fill via the weir. This loss of storage is accounted for in the models and the pond is sized to provide sufficient storage volume in addition to this amount. Multi-Use Design The developer recognizes that the proposed detention pond will remove a large part of the natural vegetation along the stream bank through the site. The pond will also be physically separated from the rest of the subdivision when construction of Eagle Avenue is completed. As a result, there is a high potential that the pond will not receive the attention or maintenance that it should. If left alone without proper maintenance, the pond will eventually become overgrown with undesirable vegetation and potentially loose its effectiveness as a flood control device. It an attempt to address this scenario, the proposed detention pond has been designed slightly larger than what is needed to meet the city's drainage requirements. Its size and shape have been laid out such that it can accommodate three practice soccer fields as shown in Exhibit D. These are youth size fields that are intended to supplement those being planned in the nearby city park adjacent to Creekview Elementary School. These fields will provide an amenity to the residential neighborhoods in the area much like those in Edelweiss Park along Victoria Avenue. As a result, it is likely that they will be maintained properly, thus allowing the pond to provide its intended level of flood protection. Conclusions and Recommendations The detention pond shown in Exhibit D provides sufficient storage capabilities to prevent 100-yr water surface elevations in the South Fork of Lick Creek from increasing following full development of the Dove Crossing Subdivision. Since the development is located adjacent to a Primary Stream as identified by the BCS Drainage Design Guidelines, it does not have to be designed to regulate flows from lower frequency storms. Therefore, we conclude that it is in compliance with the detention requirements for the City of College Station. It is recommended that the detention pond shown in Exhibit D be constructed as part the next phase of the Dove Crossing Subdivision and fulfill the requirements of the Preliminary Plat for all remaining phases. Reach Table 2 Comparison of Pre-Development and Post-Development Runoff Rates River Sta Profile • :9±.~i;cr~~~~glt~x•••:-_ -~~9i~J.!.!~i~~~~$.~~~~y - , cfs) l (ft) (cfs) I (ft) Change in WSEL Upper Reach I 7237.50 i Max WS 1,210 286.99 1,211 I 286.99 0.00 Upper Reach I 7053.31 ! Max WS 1,211 286.78 1,212 l,: 286.77 -0.01 Upper Reach ! 6949.65 ' Max WS 1,212 286.67 1 213 286.67 0.00 Upper Reach I 6829.90 I Max WS 1,213 286.54 1 :213 ,1 286.53 -0.01 Upper Reach I 6784.00 1 1 Max WS 1,212 286.39 1,211 ! 286.38 -0 01 Upper Reach ! 6752.00 Max WS 1, 158 283.39 915 I 283.24 -0.15 --u:i~~~ORu~f~i?---1---?6696d:6-oQ ____ I--~:: ~~---l---------\-: ... l.::::~·4··0: .. 4···:····--·-··-i-----------=~-~::-:-·-:.: •.. ~.: ... ~~: _____________ j ____ !!lF---l -~~H~-----------~6:~~-- Alex-Outfall ! 688.47 I Max WS 110 284.84 62 i 284.65 -0.19 Alex-Outfall I 609.29 1 Max WS 110 284.82 -159 ! 284.53 -0.29 Alex-Outfall ! ~99:99_ _ __ 1 ! Max WS 102 284.73 _ ~-1-~7-___ ] }~~:?.~ __ :9:~9 ___ _ ~~~~:: :~~-~ --r--~~ ~ ~: ~~ I --~::~~ -t----------~----:···;···:··---~-------------+------------~----~---·:··--:-· ;--~-----------------t ~ : ~:~ I ~~:: ~~ :~: ~ ~ Across Pond I 6409.00 MaxWS 1,346 284.05 ~·,;;~ !_i 283.95 -0.10 Across Pond i 6222.00 Max WS 1,346 283.56 1 283.47 -0.09 Across Pond I 6161 .00 MaxWS 1,346 283.45 1 275 ' 283.35 -0.10 Across Pond i 6160.00 MaxWS 1,346 283.45 1:275 _,!I 283.35 -0.10 Across Pond l 6040.00 Max WS 1,340 283.00 1,267 282.88 -0.12 Across Pond __________ ,! _________________ 6 ____ 0 _____ 3 _____ 6 _____ -__ o ____ o ___________________ -+---------------M ________ a ____ x __ w _______ s __________________ +-----------1 ___ :' .. 3 ____ 4 _____ 0 ______________ , ____________ 2 ___ 8 _____ 2 _____ -__ 9 ____ 8 ____ --------------1--~~--?..?..7-.. L --.?..~?..:.~_!?._______________ -~9: ~?.- DoveXi ngOutfa 11 210.00 Max WS 11 283.30 132 i 282.87 -0.43 DoveXingOutfall 208.39 Max WS 11 283.30 132 I 282.87 -0.43 DoveXingOutfall 126.62 Max WS 174 282.99 132 i 282.85 -0.14 ___ D __ o ___ v ____ e _____ x ______ i __ n ____ g ____ o ______ u ____ t __ f __ a _____ l __ I _____ •---------------------7 _____ 8 _____ -___ 1 ____ 6 ______________________ , _________________ M _______ a ____ x ______ w _______ s _______________ ... ____________ 1 ____ 7 _____ 4 __________ ,_ _____ 2 ___ 8 _____ 3 ____ -__ 0 _____ 1 __________________ , ________ !~.?. __ j_ ___ ?.~?.:~_?.__ _ _________________ :9.: __ ~ __ f?. ______________ _ Lower Reach 5929.00 Max WS 1,514 282.98 1,414 I 282.86 -0.12 Lower Reach 5813.00 Max WS 1,514 282.27 1,413 I 282.14 -0.13 Lower Reach 5602.00 Max WS 1,532 281 .82 1,429 _I 281 .68 -0.14 Lower Reach 5306.00 Max WS 1,601 281 .54 1,490 281.41 -0.13 j LowerReach 5186.00 MaxWS 1,600 281 .33 1,489 ! 281 .20 -0.13 Lower Reach 5036.00 Max WS 1,599 280.76 1,488 I 280.62 -0.14 LowerReach 4916.00 MaxWS 1,614 280.19 1,498 ! 280.04 -0.15 Lower Reach 4796.00 Max WS 1,630 280.04 1,496 i 279.90 -0.14 Lower Reach 4566.00 Max WS 1,646 279.62 1,535 I 279.47 -0.15 Lower Reach 4296.00 Max WS 1,663 278.82 1,561 I 278.65 -0.17 LowerReach 3846.00 MaxWS 1,697 277.28 1,619 ! 277.07 -0.21 Lower Reach 3651 .00 Max WS 1,704 277.08 1,632 I 276.85 -0.23 Lower Reach 3596.00 Max WS 1,703 277.00 1,631 I 276.71 -0.29 Lower Reach 3582.00 Max WS 1,703 276.66 1,631 ! 276.40 -0.26 Lower Reach 3524.00 Max WS 1,703 275.58 1,631 ; 275.56 -0.02 Lower Reach 3506.00 Max WS 1,703 275.95 1,630 I 275.90 -0.05 Lower Reach 3453.00 Max WS 1,703 276.00 1,630 I 275.94 -0.06 Lower Reach 3396.00 Max WS 1,712 275.95 1,640 i 275.90 -0.05 Lower Reach 3186.00 Max WS 1,746 275.58 1,676 I 275.55 -0.03 Lower Reach 2866.00 Max WS 1,793 275.26 1,733 1 275.24 -0.02 Lower Reach 2546.00 Max WS 1,789 275.05 1,731 ! 275.05 0.00 To the City Engineer for the City of College Station, Texas: Re: Dove Crossing Subdivision, Phases 1-9 Certification Statement I have conducted a topographic review and field investigation of the existing and proposed flow patterns for stormwater runoff from the Dove Crossing Subdivision to the main stem of the South Fork of Lick Creek. At build-out conditions allowable by zoning, restrictive covenant, or plat note, the stormwater flows from the subject subdivision or site project will not cause any increase in flooding conditions to the interior of existing building structures, including basement areas, for storms of magnitude up through the 100-yr event. IDS-12..3 Tx License No. Seal Exhibit A Dove Crossing Subdivision Preliminary Plat (2 sheets) Exhibit B Dove Crossing Drainage Study Drainage Area Map Pre-Development Conditions Exhibit C Dove Crossing Drainage Study Drainage Area Map Post-Development Conditions Exhibit D Dove Crossing Drainage Study Proposed Detention Pond Exhibit E Dove Crossing Drainage Study Cross-Section Location Map (Exhibit 2 from Mitchell & Morgan Report Exhibit F Dove Crossing Drainage Study HEC-RAS Unsteady Flow Analysis Output Data Report Reach River Sta Profile Plan Upper Reach 10682.81 MaxWS Exist_IOO Upper Reach 10682.81 MaxWS Prop_IOO Upper Reach 10662.22 MaxWS Exist 100 Upper Reach 10662.22 MaxWS Prop_IOO Upper Reach 10514.04 MaxWS Exist_IOO Upper Reach 10514.04 MaxWS Prop_IOO Upper Reach 10381.4 MaxWS Exist_IOO Upper Reach 10381.4 MaxWS Prop_IOO Upper Reach 10242.58 MaxWS Exist_lOO Upper Reach 10242.58 MaxWS Prop_lOO Upper Reach 10136.51 MaxWS Exist 100 Upper Reach 10 136.51 MaxWS Prop_IOO Upper Reach 10054.43 MaxWS Exist 100 Upper Reach 10054.43 MaxWS Prop_lOO Upper Reach 9917.48 MaxWS Exist_lOO Upper Reach 9917.48 MaxWS Prop_lOO Upper Reach 9885.62 MaxWS Exist 100 Upper Reach 9885.62 MaxWS Prop_IOO Upper Reach 9844.46 Creek Crossing Upper Reach 9815.97 MaxWS Exist_lOO Upper Reach 9815.97 MaxWS Prop_lOO Upper Reach 9768.67 MaxWS Exist 100 Upper Reach 9768.67 MaxWS Prop_lOO Upper Reach 9715.89 MaxWS Exist_IOO Upper Reach 9715.89 MaxWS Prop_lOO Upper Reach 9629.97 MaxWS Exist_lOO Upper Reach 9629.-97 Max WS Prop_IOO Upper Reach 9557.98 Max WS Exist_lOO Upper Reach 9557.98 Max WS Prop_IOO Ex it F Results from HEC-RAS Unsteady Flow Analysis April-09 QTotal Min Ch El W.S. Elev CritW.S. E.G. Elev E.G. Slope (cfs) (ft) (ft) (ft) (ft) (ft/ft) 661 .68 290.65 296.35 296.44 0.001163 662.99 290.65 296.35 296.44 0.001165 661.43 290.63 296.12 296.42 0.004227 662.76 290.63 296.13 296.42 0.004229 686.78 289.64 295.9 296.02 0.00106 688.1 289.64 295.9 296.02 0.001058 710.31 288.09 295.61 295.8 0.002767 711.64 288.09 295.61 295.8 0.002767 728.14 288.63 295.2 295.44 0.004283 729.52 288.63 295.2 295.44 0.004284 744.75 288.19 294.8 295.07 0.003656 746.13 288.19 294.8 295.07 0.003659 758.68 287.95 294.75 294.81 0.000515 760.07 287.95 294.75 294.81 0.000516 787.19 287.8 293.97 294.42 0.007224 788.67 287.8 293.97 294.43 0.00725 1 793.31 286.09 293.96 294.18 0.0024Q2 794.8 286.09 293.96 294.18 0.0024 12 Culvert 793 .31 286.09 293.94 294.06 0.001244 794.8 286.09 293.95 294.06 0.001245 799.83 286.77 293.4 1 294.03 0.009895 801.33 286.77 293.41 294.04 0.009895 810.82 286.03 293 .34 293.43 0.00181 812.34 286.03 293.34 293.44 0.001811 823.58 285 .92 293.06 293.29 0.003691 825.12 285.92 293.07 293.29 0.003692 834.16 286.02 292.97 293.06 0.001563 835.72 286.02 292.97 293.06 0.001564 Page 1 Ve! Chnl Flow Area Top Width Froude # (ft/s) (sq ft) (ft) Chi 2.5 279.24 95.48 0.22 2.51 279.53 95.52 0.22 4.56 174.9 108.92 0.41 4.56 175.23 109.05 0.41 2.15 272.12 171.21 0.2 2.15 272.69 171.29 0.2 4.57 339.65 171.81 0.34 4.57 340.22 172.1 0.34 5.2 295.44 124.91 0.41 5.21 295.86 124.95 0.41 5.03 283.87 132.65 0.38 5.03 284.26 132.74 0.38 2.13 445.01 148.03 0.16 2.13 445.45 148.15 0.16 6.15 190.97 175.72 0.54 6.16 190.97 175.72 0.54 3.95 242.83 96.17 0.31 3.96 242.77 96.09 0.31 3.02 316.84 119.62 0.22 3.02 317.25 119.75 0.22 7.54 19 1.98 97.23 0.62 7.54 192.31 97.3 l 0.62 3.47 478.37 176.67 0.28 3.47 478.97 176.75 0.28 5.04 366.62 165.55 0.39 5.04 367.19 165.61 0.39 3.36 529.14 191.33 0.26 3.36 529.8 l 191.43 0.26 Reach River Sta Profile Plan Upper Reach 9414.57 MaxWS Exist_ LOO Upper Reach 9414.57 MaxWS Prop_lOO Upper Reach 9312.99 MaxWS Exist_lOO Upper Reach 9312.99 MaxWS Prop_lOO Upper Reach 9144.64 MaxWS Exist_lOO Upper Reach 9144.64 MaxWS Prop_lOO Upper Reach 9023.13 MaxWS Exist LOO Upper Reach 9023.13 MaxWS Prop_LOO Upper Reach 8927.77 MaxWS Exist 100 Upper Reach 8927.77 MaxWS Prop_IOO Upper Reach 8871.44 MaxWS Exist_lOO Upper Reach 8871.44 MaxWS Prop_lOO Upper Reach 8782.86 MaxWS Exist LOO Upper Reach 8782.86 MaxWS Prop_lOO Upper Reach 8697.49 MaxWS Exist 100 Upper Reach 8697.49 MaxWS Prop_lOO Upper Reach 8553.03 MaxWS Exist_lOO Upper Reach 8553.03 MaxWS Prop_l OO Upper Reach 8496.27 MaxWS Exist_ LOO Upper Reach 8496.27 MaxWS Prop_LOO Upper Reach 848l.13 Max ws · Exist_ LOO Upper Reach 8481.13 MaxWS Prop_lOO Upper Reach 8449.57 Proposed Eagle A Upper Reach 841 l.52 MaxWS Exist_lOO Upper Reach 841 l.52 MaxWS Prop_lOO Upper Reach 8351. 7 MaxWS Exist 100 Upper Reach 8351. 7 MaxWS Prop_lOO Upper Reach 8160.12 MaxWS Exist_IOO Upper Reach 8160.12 MaxWS Prop_LOO Exl t F Results from HEC-RAS Unsteady Flow Analysis April-09 QTotal Min Ch El W.S. Elev Crit W.S. E.G. Elev E.G. Slope (cfs) (ft) (ft) (ft) (ft) (ft/ft) 855.29 285.26 292.78 292.87 0.001415 856.89 285.26 292.78 292.87 0.00141 872.54 284.96 291.79 292.58 0.011325 874.17 284.96 291.79 292.59 0.011333 868.38 282.82 290.83 29l.l 0.005314 869.74 282.82 290.84 29l.l 0.005315 867.38 283.26 290.34 290.51 0.004067 868.77 283.26 290.3 4 290.52 0.004066 866.35 283.05 290.04 290.22 0.003057 867.75 283.05 290.04 290.23 0.003058 865.54 282.09 289.85 290.03 0.002776 866.94 282.09 289.86 290.03 0.002778 864.25 283.46 289.72 289.8 0.001869 865.64 283.46 289.72 289.8 0.00187 862.72 283.52 289.52 289.69 0.001978 864.08 283.52 289.53 289.69 0.001979 898.44 282.9 289.4 289.5 0.000123 899.71 282.9 289.41 289.5 0.000123 958.94 282.64 289.4 289.47 0.000088 960.15 282.64 289.4 289.48 0.000088 958.7 282.28 289.38 289.47 0.000083 959.91 282.28 289.38 289.47 0.000083 Culvert 958.7 28 l.78 288.87 288.99 0.000121 959.91 28 l.78 288.88 288.99 0.000121 957.85 282.22 288.73 288.92 0.003083 959.08 282.22 288.73 288.92 0.003087 948.5 282.31 288.52 288.58 0.000594 949.71 282.31 288.52 288.58 0.000595 Page 2 Vel Chnl Flow Area Top Width Froude # (ft/s) (sq ft) (ft) Chi 3.37 452.46 229.47 0.25 3.37 453.38 229.65 0.25 8.47 188.89 84.l 0.67 8.47 189.16 84.16 0.67 5.4 315.12 143.75 0.43 5.4 315.52 143.85 0.43 5.21 425.24 190.79 0.39 5.21 425.82 190.91 0.39 4.74 430.86 186.26 0.35 4.74 431.4 186.35 0.35 4.54 389.32 146.46 0.32 4.55 389.72 146.54 0.32 3.47 587.04 242.16 0.28 3.47 587.69 242.26 0.28 4.61 514.26 219.52 0.36 4.61 514.83 219.59 0.36 2.63 619.8 219.91 0.19 2.63 620.35 220.13 0.19 2.28 521.77 224.8 0.16 2.28 522.36 225.11 0.16 2.39 406.5 l 192.5 0.16 2.39 406.84 193.83 0.16 2.77 391.96 186.7 0.19 2.77 392.05 186.75 0.19 4.55 373.26 193.52 0.36 4.55 373.45 193.59 0.36 2.3 709.3 217.23 0.17 2.31 709.5 217.29 0.17 Reach River Sta Profile Plan Upper Reach 7974.76 Ma.x.WS Exist 100 Upper Reach 7974.76 Ma.x.WS Prop_IOO Upper Reach 7782.43 Ma.x.WS Exist_ JOO Upper Reach 7782.43 Ma.x.WS Prop_IOO Upper Reach 7623.63 Ma.x.WS Exist_ JOO Upper Reach 7623.63 Ma.x.WS Prop_lOO Upper Reach 7424.84 Ma.x.WS Exist_ JOO Upper Reach 7424.84 Ma.x.WS Prop_IOO Upper Reach 7237.5 Ma.x.WS Exist_ JOO Upper Reach 7237.5 Ma.x.WS Prop_IOO Upper Reach 7053.3 1 Ma.x.WS Exist_lOO Upper Reach 7053.3 1 Ma.x.WS Prop_lOO Upper Reach 6949.65 Ma.x.WS Exist_lOO Upper Reach 6949.65 Ma.x.WS Prop_lOO Upper Reach 6829.9 Ma.x.WS Exist_ JOO Upper Reach 6829.9 Ma.x.WS Prop_lOO Upper Reach 6784 Ma.x.WS Exist_lOO Upper Reach 6784 Ma.x.WS Prop_lOO Upper Reach 6752 Ma.x.WS Exist_lOO Upper Reach 6752 Ma.x.WS Prop_lOO Upper Reach 6661 Ma.x.WS Exist_lOO Upper Reach 6661 Ma.x.WS Prop_lOO Alex-Outfall 690 Ma.x.WS Exist 100 Alex-Outfall 690 Ma.x.WS Prop_IOO Alex-Outfall 688.47 Ma.x.WS Exist_lOO Alex-Outfall 688.47 Ma.x.WS Prop_lOO Alex-Outfall 609.29 Ma.x.WS Exist_lOO Alex-Outfall 609.29 Ma.x.WS Prop_lOO Alex-Outfall 400 Ma.x.WS Exist_lOO Alex-Outfall 400 Ma.x.WS Prop_lOO Exl t F Results from HEC-RAS Unsteady Flow Analysis April-09 Q Total Min Ch El W.S. Elev Crit W.S. E.G. Elev E.G. Slope (cfs) (ft) (ft) (ft) (ft) (ft/ft) 947.54 282.31 288.26 288.38 0.002514 948.74 282.31 288.26 288.39 0.00252 1214.34 282.31 287.88 288 0.002827 1215.53 282.31 287.88 288 0.002836 1214.55 281 .87 287.61 287.68 0.002013 1215.74 281.87 287.61 287.68 0.002021 1206.8 280.05 287.29 287.42 0.002042 1207.88 280.05 287.29 287.42 0.002051 1209.64 280.21 286.99 287.08 0.002036 1210.65 280.21 286.99 287.08 0.002051 1211.06 280.21 286.78 286.87 0.001363 1211.96 280.21 286.77 286.87 0.001374 1212.48 280.21 286.67 286.73 0.000892 1213.23 280.21 286.67 286.73 0.000898 1212.68 280.21 286.54 286.77 0.002283 1212.66 280.21 286.53 286.76 0.002304 1211.56 280.21 286.39 286.58 0.001598 1211.11 280.21 286.38 286.56 0.00161 1158.44 277.06 283.39 283.32 286.47 0.006884 915.15 277.06 283.24 285.25 0.004675 1244.2 277.06 284.73 284.89 0.000876 1234.95 277.06 284.63 284.8 0.000952 109.87 281 284.84 284.87 0.000184 61.89 281 284.65 284.66 0.000072 109.87 281 284.84 284.87 0.000184 61.89 281 284.65 284.66 0.000072 109.83 281 284.82 284.85 0.000228 -158.96 281 284.53 284.62 0.000641 101.83 279 284.73 284.78 0.000404 -187.03 279 284.63 284.8 0.001485 Page 3 Vel Chnl Flow Area Top Width Froude # (ft/s) (sq ft) (ft) Chi 3.98 550.17 373.09 0.33 3.98 550.24 373.12 0.33 4.09 668.7 431.48 0.35 4.1 668.34 431.45 0.35 3.2 777.72 352.21 0.29 3.2 777.08 352.18 0.29 4.01 611.71 237.03 0.3 4.01 610.97 236.5 0.31 3.45 745.66 333.73 0.29 3.47 743.99 332.87 0.29 3.23 717.84 310.36 0.25 3.24 715.8 309.91 0.25 2.51 795.75 313.07 0.2 2.52 793.49 312.37 0.2 3.84 328.33 342.85 0.32 3.85 327.18 337.46 0.32 3.42 367.77 268.24 0.27 3.43 366.67 266.4 0.27 14.07 82.34 170.71 0.99 11.4 80.28 161.08 0.81 3.41 541.92 226.03 0.31 3.5 520.28 215.66 0.33 l.56 79.99 27.5 0.15 0.94 74.83 27.5 0.09 1.56 79.98 27.5 0.15 0.94 74.83 27.5 0.09 1.57 74 .97 24.75 0.15 -2.52 67.81 24.75 0.24 l.49 59.92 17 0.13 -2.82 58.26 17 0.24 Reach River Sta Profile Plan Across Pond 6618 MaxWS Exist_IOO Across Pond 6618 MaxWS Prop_IOO Across Pond 6615 MaxWS Exist_lOO Across Pond 6615 MaxWS Prop_lOO Across Pond 6409 MaxWS Exist_lOO Across Pond 6409 MaxWS Prop_lOO Across Pond 6222 MaxWS Exist_lOO Across Pond 6222 MaxWS Prop_100 Across Pond 6161 MaxWS Exist_IOO Across Pond 6161 MaxWS Prop_lOO Across Pond 6160 MaxWS Exist_IOO Across Pond 6160 MaxWS Prop_IOO Across Pond 6040 MaxWS Exist 100 Across Pond 6040 MaxWS Prop_IOO Across Pond 6036 MaxWS Exist_100 Across Pond 6036 MaxWS Prop_IOO DoveXingOutfall 210 MaxWS Exist 100 DoveXingOutfall 210 MaxWS Prop_lOO DoveXingOutfall 208.39 MaxWS Exist_lOO DoveXingOutfall 208.39 MaxWS Prop_100 DoveXingOutfaU 126.62 MaxWS Exist_lOO DoveXingOutfall 126.62 MaxWS Prop_lOO DoveXingOutfall 78.16 MaxWS Exist_IOO DoveXingOutfall 78.16 MaxWS Prop_lOO DoveXingOutfall 23.3 MaxWS Prop_lOO DoveXingOutfall 12.24 MaxWS Prop_lOO DoveXingOutfall 0 MaxWS Exist_IOO Lower Reach 5929 MaxWS Exist_lOO Lower Reach 5929 MaxWS Prop_lOO Exl t F Results from HEC-RAS Unsteady Flow Analysis April-09 QTotal Min Ch El W.S. Elev CritW.S. E.G. Elev E.G. Slope (cfs) (ft) (ft) (ft) (ft) (ft/ft) 1346.03 277.26 284.73 285.14 0.004076 1047.91 277.26 284.63 284.91 0.002785 1346.02 277.26 284.72 285.13 0.004164 1047.91 277.26 284.62 284.91 0.002818 1345.82 275.24 284.05 284.3 0.004189 1275.17 275.24 283.95 284.18 0.004011 1345.62 275.92 283.56 283.7 0.002461 1274.66 275.92 283.47 283.6 0.002426 1345.6 275.91 283.45 283.57 0.001933 1274.52 275.91 283.35 283.47 0.001932 1345.6 275.91 283.45 283.57 0.001937 1274.52 275.91 283.35 283.47 0.001936 1340.41 275.63 283 283.21 0.00449 1267.38 275.63 282.88 283.09 0.004699 1340.38 275.63 282.98 283.19 0.004618 1267.34 275.63 282.86 283.07 0.004848 10.63 281 283.3 283.31 0.000004 132.4 279 282.87 282.91 0.000323 10.63 28 1 283.3 283.31 0.000004 132.4 279 282.87 282.91 0.000323 174.08 28 1 282.99 283.1 0.001544 132.3 278 282.85 282.88 0.000242 174.04 279 283.01 283.06 0.000339 132.21 278 282.85 282.87 0.00023 132.l 275.5 282.86 282.86 0.00003 146.48 275.5 282.86 282.86 0.000015 174 278 282.98 283.03 0.000277 1514.37 276.1 282.98 283.22 0.006422 1413.82 276.1 282.86 283.l 0.006612 Page4 Vet Chnl Flow Area Top Width Froude # (ft/s) (sq ft) (ft) Chi 6.66 479 321.56 0.64 5.46 451.49 271.22 0.53 6.72 474.1 291.66 0.65 5.49 448.81 270.3 0.53 4.19 433.87 274.01 0.4 4.02 409.98 208.76 0.39 3.5 557.77 215.2 0.32 3.42 537.12 208.88 0.31 3.68 678.47 261.58 0.29 3.63 652.66 261.11 0.29 3.68 677.92 261.57 0.29 3.63 652.11 261.l 0.29 4.04 465.93 256.51 0.41 4.04 436.01 249.75 0.42 4.08 460.45 255.29 0.42 4.09 430.25 248.43 0.43 0.15 72.05 40.44 0.02 1.52 86.99 37.96 0.18 0.15 72.05 40.44 0.02 1.52 86.97 37.95 0.18 2.66 65.44 40.48 0.37 1.37 96.92 39.9 0.15 1.66 104.89 41.75 0.18 1.27 104.33 46.53 0.15 0.62 214.26 56.4 0.06 0.52 280.91 55.5 0.04 1.85 93.91 19.71 0.15 5.25 518.06 276.08 0.5 5.2 485.35 269.62 0.5 Reach River Sta Profile Plan Lower Reach 5813 MaxWS Exist_lOO Lower Reach 5813 MaxWS Prop_IOO Lower Reach 5602 MaxWS Exist_IOO Lower Reach 5602 MaxWS Prop_lOO Lower Reach 5306 MaxWS Exist_IOO Lower Reach 5306 MaxWS Prop_IOO Lower Reach 5186 MaxWS Exist_lOO Lower Reach 5186 MaxWS Prop_IOO Lower Reach 5036 MaxWS Exist_lOO Lower Reach 5036 MaxWS Prop_lOO Lower Reach 4916 MaxWS Exist_lOO Lower Reach 4916 MaxWS Prop_IOO Lower Reach 4796 MaxWS Exist_IOO Lower Reach 4796 MaxWS Prop_IOO Lower Reach 4566 MaxWS Exist_IOO Lower Reach 4566 MaxWS Prop_IOO Lower Reach 4296 MaxWS Exist_lOO Lower Reach 4296 MaxWS Prop_lOO Lower Reach 3846 MaxWS Exist_lOO Lower Reach 3846 MaxWS Prop_lOO Lower Reach 3651 MaxWS Exist_IOO Lower Reach 3651 MaxWS Prop_IOO Lower Reach 3596 MaxWS Exist_IOO Lower Reach 3596 MaxWS Prop_IOO Lower Reach 3582 MaxWS Exist_IOO Lower Reach 3582 MaxWS Prop_IOO Lower Reach 3553 Lower Reach 3524 MaxWS Exist_lOO Lower Reach 3524 MaxWS Prop_lOO Exl(., )t F Results from HEC-RAS Unsteady Flow Analysis April-09 Q Total Min Ch El W.S. Elev CritW.S. E.G. Elev E.G. Slope (cfs) (ft) (ft) (ft) (ft) (ft/ft) 1513.52 275.61 282.27 282.61 0.004442 1412.94 275.61 282.14 282.48 0.004491 1532.35 275 281.82 281.91 0.001371 1429.33 275 281.68 281.77 0.001378 1600.57 275 281.54 281.63 0.001318 1489.52 275 281.41 281.49 0.001285 1599.92 273 281.33 281.47 0.001542 1488.96 273 281.2 281.34 0.001483 1598.88 273.37 280.76 280.96 0.005489 1488.44 273.37 280.62 280.82 0.00561 1614.02 273.64 280.19 280.29 0.001047 1498.37 273.64 280.04 280.14 0.001034 1629.86 271.81 280.04 280.09 0.000862 1496.25 271.81 279.9 279.94 0.000817 1645.55 271.5 279.62 279.74 0.002392 1534.56 271.5 279.47 279.59 0.002468 1663.09 271.28 278.82 278.99 0.004202 1560.73 271.28 278.65 278.82 0.004288 1696.61 268.93 277.28 277.51 0.002523 1619 268.93 277.07 277.3 0.00264 1704.33 268.7 277.08 277.21 0.00208 1632.01 268.7 276.85 276.99 0.002352 1703.38 267.97 277 277.07 0.000081 1630.94 267.97 276.71 276.92 0.00017 1703.06 267.6 276.66 277.21 0.000425 1630.62 267.6 276.4 276.94 0.000428 Culvert 1703.06 267.48 275.58 276.27 0.000616 1630.62 267.48 275.56 276.2 0.000569 Page 5 Ve! Chnl Flow Area Top Width Froude # (ft/s) (sq ft) (ft) Chi 5.15 443.7 265.7 0.44 5.07 409.26 251.44 0.44 3.38 900.58 331.5 0.25 3.33 854.5 328.78 0.25 2.88 859.87 284.13 0.24 2.81 821.76 280.03 0.24 3.65 715.82 248.38 0.27 3.52 684.92 242.84 0.26 6.03 609.53 277.63 0.42 6.01 571.66 270.47 0.42 2.96 895.05 347.8 0.22 2.89 843.15 341.45 0.22 2.89 1213.35 375.17 0.19 2.77 1159.81 362.27 0.19 4.51 872.48 371.8 0.3 4.51 816.22 362.66 0.31 5.74 697.29 300.31 0.42 5.68 647.26 279.1 0.42 5.13 698.1 271.94 0.34 5.14 643.49 247.07 0.35 4.47 826.2 275.89 0.28 4.66 762.18 269.18 0.29 3.22 1090.96 285.1 0.19 4.57 483.79 276.88 0.27 5.97 285.27 270.97 0.35 5.88 277.25 257.3 0.35 6.67 255.27 228.56 0.41 6.4 254.66 227.77 0.4 Reach River Sta Profile Plan Lower Reach 3506 MaxWS Exist_IOO Lower Reach 3506 MaxWS Prop_lOO Lower Reach 3453 MaxWS Exist 100 Lower Reach 3453 MaxWS Prop_IOO Lower Reach 3396 MaxWS Exist 100 Lower Reach 3396 MaxWS Prop_lOO Lower Reach 3186 MaxWS Exist_lOO Lower Reach 3186 MaxWS Prop_lOO Lower Reach 2866 MaxWS Exist_lOO Lower Reach 2866 MaxWS Prop_lOO Lower Reach 2546 MaxWS Exist_lOO Lower Reach 2546 MaxWS Prop_lOO Lower Reach 2526 MaxWS Exist_lOO Lower Reach 2526 MaxWS Prop_lOO Lower Reach 2361 Lower Reach 2196 MaxWS Exist 100 Lower Reach 2196 MaxWS Prop_IOO Lower Reach 2036 MaxWS Exist 100 Lower Reach 2036 MaxWS Prop_lOO Exl t F Results from HEC-RAS Unsteady Flow Analysis April-09 Q Total Min Ch El W.S. Elev CritW.S. E.G. Elev E.G. Slope (cfs) (ft) (ft) (ft) (ft) (ft/ft) 1703.03 267.36 275.95 276.17 0.000193 1630.47 267.36 275 .9 276.l 0.000183 1702.86 267.03 276 276.09 0.000856 1629.96 267.03 275.94 276.03 0.000817 1711.98 266.68 275.95 276.02 0.001309 1639.72 266.68 275 .9 275.97 0.001258 1745.81 265.63 275.58 275.77 0.001514 1675.79 265.63 275.55 275.73 0.001428 1792.81 264.95 275.26 275.31 0.000923 1733 264.95 275.24 275.29 0.000873 1789.36 263.78 275.05 275.08 0.000331 1730.54 263.78 275.05 275.08 0.00031 1902.5 260.64 274.89 275.17 0.000095 1898.23 260.64 274.89 275.17 0.000095 Culvert 108.76 260.64 274 274 0 108.49 260.64 274 274 0 108.76 262.65 274 263.74 274 0.000001 108.49 262.65 274 263.74 274 0.000001 Page 6 Vel Chnl Flow Area Top Width Froude # (ft/s) (sq ft) (ft) Chi 4.76 683.9 218.52 0.29 4.62 673.14 216.25 0.28 2.97 986.91 310.74 0.21 2.89 970.73 309.52 0.2 3.63 1048.22 339.73 0.23 3.55 1031.05 338.87 0.22 4.28 785.51 303.32 0.27 4.14 775.88 300.5 0.26 3.25 1353.6 455.08 0.19 3.15 1347.41 454.11 0.18 2.25 2020.52 637.92 0.13 2.17 20 19.25 637.69 0.12 4.25 447.95 32 0.2 4.24 447.82 32 0.2 0.26 419.42 32 0.01 0.26 419.42 32 0.01 0.12 2109.67 650 0.01 0.12 2109.67 650 0.01 Appendix 1 Dove Crossing Drainage Study Detention Pond Analysis Mitchell & Morgan Engineers & Constructors DOVE CROSSING SUBDIVISION DETENTION POND ANALYSIS February 2009 Prepared for: CIVIL DEVELOPMENT, LTD 2033 HARVEY MITCHELL PARKWAY SOUTH COLLEGE STATION, TX 77840 (979) 764-7743 By MITCHELL MM MORGAN ENG INEERS & CONSTRUCTORS 511 UNIVERSITY DRIVE, SUITE 204 COLLEGE STATION, TX 77840 OFFICE (979) 260-6963 FAX (979) 260-3564 CERTIFICATION This report for the detention pond analysis for the Dove Crossing Subdivision was prepared under my supervision in accordance with provisions of the Bryan/College Station Unified Drainage Design Guidelines for the owners of the property. All licenses and permits required by any and al l state and federal regulatory agencies for the proposed drainage improvements have been issued. Dove Crossing Subdivision The purpose of this report is to state findings on the Dove Crossing detention pond analysis. The pond is located near the South Fork of Lick Creek and south of the Dove Cross ing Subdivision in College Station . The objective of the proposed detention pond is to attenuate fl ow in Lick Creek so that development would have no adverse effects downstream (River Station 5929 and under). A dynamic model for Lick Creek was used to analyze the results of the proposed detention pond design on the Lower Lick Creek reach. The proposed detention pond was designed based on 100 year flood event conditions as provided by the Unified Stormwater Design Gu idelines which states that detention ponds adjacent to the primary system need only be designed for a 100 year return period. The proposed detention pond was graded as shown in Exhibit 1. The pond has a bottom elevation of 276.5 and top elevation of 285.0 feet. Table 1 contains the elevation-area- volume for the detention pond. Tabl e 1: Detention Pond Storage Volume Elevation Area (sf) (Ac-ft) 276.5 3168 0.00 277 26077.15 0.10 278 57006.68 1.03 .279 84550.39 2.65 . 280 90362.07 4.65 281 96274.86 6.79 '282 102287.61 9.07 283 108401.17 11.49 284 114250.17 14.05 .. •, 285 11 9828.34 16.73 Based on the pond location, a portion of the pea k flow from Dove Crossing Subdivision through t he channel parallel to Alexandria Avenue and a portion of the peak flow from Lick Cree k South Fo rk will be diverted into the pond. Weirs were placed along the pond on the upstream side to redirect flow into the pond and reduce maximum water surface elevation downstre am so as not to exceed the existing conditions. A culvert was placed on the downstream side of the pond mainly for draining purposes after flood events have past. The proposed culvert will be a 21" RCP pipe. The wei r will be constructed on two sides of the detention pond, be in g parallel and perpendicular to Lick Creek. The weir will span a length of 175 feet and have a graded top elevation of 283.5'. During a 100 year flood event, flow w ill be diverted into the pond from drainage conveyed from Dove Crossing Subdivision (parallel to Alexandria Avenue) and pa rtial flow from Lick Creek South Fork. The maximum water surface elevation above the weir will be approximately 1.2 foot. Weir dimensions can be seen below in Table 2. Table 2: Weir Dimensions " Weir Dimensions ' Description . Lenqth (ft) W idth (ft) Top Elev (ft) Weir Type 1 Perpendicular to Lick Creek South Fork Broad-Crested 100 5 283.5 2 Parallel to Lick Creek South Fork B road -Crested 75 5 283.5 **Both weirs location on upstream side of detention pond Dove Crossing Subdivision Based on the res ults found from the analysis of Lick Creek South Fork, including the proposed detention pond, downstream conditions for the 100 yea r flood event were reduced below the ex isting conditions. As mentioned, flow will not be detained until the water surface elevation in Lick Creek at the proposed weir exceeds 283.5'. However, capacity will be used due to backflow through the proposed drainage culvert from Lick Creek. The base water surface elevation within the pond due to only f low in from the drainage culvert will be approximately 280'. Desp ite the capacity at lower elevations bein g consumed, sufficient storage will be ava ilable to detain flow from the 100 yea r flood event. By viewing Table 3, the maximum water surface elevation in the detention pond is 284.57', leaving approximately 0.5' of freeboard. Results contained in Appendix A show the output for cross sections located just upstream, adjacent, and just downstream of the proposed pond; as well as the most downstream location . The output contains the water surface elevations for existing and proposed conditions for the specified cross sections located just upstream, adjacent and downstream of the proposed detention pond. Exhibit 2 illustrates a cross section map of Lick Creek South Fork. Additionally, located in Appendix A is a profile illustrating the WSEL for the proposed and existing conditions 100 year flood event for Lower Lick Creek. Also attached to this report, via cd, w ill be the HEC-RAS and HEC-HMS models used in analyzing the proposed detention pond. Table 3: Detention Pond Results Storaqe Area Profile Storm Event Max WSEL · Min Pond EL SA Area ·SA Vol (ft) (ft) (ac) (ac-ft) Pond B Max WS 100 yr 284.55 276.50 2.86 15.51 In conclusion, we feel that the dynamic model used to illustrate Lick Creek creates a good representation of the effects of the proposed detention pond on the 100 year flood event. The proposed detention pond provides sufficient storage to attenuate flow from development and reduce downstream conditions to meet existing water surface elevations. S:\Proj\0804-DoveCrossDetention\docs\0804-Design_letter Dove Crossing Subdivision ----... ~p-...:.-:.~.:.:=---- 1. M -• -~ ------- ____ ....... ____ _ _ ,_...,._.,.. ____ •vr•-. =--~:-:..:..::~-.... --·----·--... --___ _,.. ....... -.. -.... -:5-s:"~-::.._:.ri:.-:.-:.=-. :.!:,.~....:.:="..::".:-.: = ':"'::::: ~-=~ o..u.-~-•·---N-•n .. ~~:c--==:u.~..:.:: ~~=--=:..~~---t,ill,j,"" ____ ,.. _______ _ -----•-.cD•'""•"-"' ----~-·------.. - _____ -::.':.-=------=:,-,,;::.:::::.:::::.:~::::€:-:~~~~~~~~~;~~~~~~f::==~=~:::~1 tt= _;:::~----------~~::::::::::::::~~-===-~~~~-:--~: LEGEND £XISTINC CONTOLlt -----2ecr---- PAOPOSCD POMO CONTOUR ROCk RtP RAP COHCRClE SPIUWAY PROPOSCD PIPE WAlLS i:mm~ - -:::.:. ----_--..,.- 1 285 275 g c -~ ~ w 270 Lick Creek -Explore Options Plan: 1) Exist_100 2/16/2009 2) Prop100 3/31/2009 Uck Creek Lower Reach Main Channel Distance (ft) Legend ws Mu: ws -ExisL 1 oo ws Max ws -Prop100 Ground HEC-RAS OUTPUT River Reach River Sta Profile Plan QTolal · Min Ch El W.S. Elev CritW.S. E.G. Elev E.G Slope Vel Chnl Flow Area Too Width Froude #Chi (cfsl (ft) (ft) (ft) (ft) (fVft) (ft/s) lsaftl (ft) Lick Creek Up1>er Reach 7053.31 MaxWS Exist 100 1211 .06 280.21 286.78 286.87 0.001363 3.23 717.84 310.36 0.25 Lick Creek Upper Reach 7053.31 MaxWS Proo100 1211 .71 280.21 286.77 286.87 0.001374 3.24 715.8 309.91 0.25 Lick Creek · Across Pond 6161 MaxWS Exist 100 1345.6 275.91 283.45 283.57 0.001933 3.68 678.47 261.58 0.29 Lick Creek Across Pond 61q1 MaxWS Prop100 1276.64 275.91 283.36 283.48 0.001922 3.62 654.69 261 .15 0.29 Lick Creek Lower Reach 5813 MaxWS Exist 100 1513.52 275.61 282.27 282.61 0.004442 5.15 443.7 265.7 0.44 Lick Creek Lower Reach 5813 MaxWS · Prop100 1421 .93 275.61 282.15 282.49 0.004478 5.08 412.79 252.94 0.44 Lick Creek Lower Reach " 2526 MaxWS . Exist 100 1902.5 260.64 274.89 275.17 0.000095 4.25 447.95 32 0.2 Lick Creek · Lower ~each 2526 MaxWS · Prop100 1901 .97 260.64 274.89 275.17 0.000095 4.25 447.94 32 0.2 284 282 g 280 c t w 278 276 274 Lick Creek -Explore Options Plan: 1) Exist_100 313112009 2) Prop100 3/31/2009 River= Lick Creek Reach= Upper Reach RS= 7053.31 -----.01 .1-+.05+-.1+.oe-J 0 j<wj Legend ws Max l/\IS -Exist_ 1 OD ws Max ws -Prop100 Ground • Bank Sta 200 300 400 500 600 700 Station (ft) Lick Creek -Explore Options Plan: 1) Exist_100 3/3112009 2) Prop100 313112009 River= Uck Creek Reach= lower Reach RS= 5813 ><------.oa----="'!'<--.o5--~-----.o8-----='1 0 100 200 Station (ft) 300 400 Legend VVS Max WS -E.ldst_ 100 WS Max WS-Prop100 Ground • Bank Sta 286 284 282 g c 0 280 ~ m ~ w 278 276 274 0 Lick Creek -Explore Options Plan: 1) Exisl_ 100 3131/2009 2) Prop100 313112009 River= lick Creek Reach = Across Pond RS= 6161 100 200 300 400 station (ft) 500 Legend Vl/S Max Vl/S -Exist_ 100 WS Max WS -Prop100 Ground • Bank Sta Lick Creek -Explore Options Plan: 1) Exist_100 3/3112009 2) Prop100 3/3112009 River"" Uck Creek Reach= Lower Reach RS z 2526 This is a REPEATED sedlon. ------==1<.D1J,.._------.o8------='1 1200 1300 1400 Station (ft) Legend ws Mu ws -Exist_ 100 WS Max \NS -Prop1 OD Ground 1500 lneff • Bank Sta Water System Report for Dove Crossing Subdivision, Phases 1-9 College Station, Texas Original Report dated September 2004 Revised A ugust 200 7 Prepared By: • Civil Development, Ltd. 2033 Harvey Mitchell Parkway College Station, Texas 77840 (979) 764-7743 GENERAL INFORMATION location: Dove Crossing Subdivision, Phases 1-9 is located on the south side of Graham Road near Victoria Avenue. Currently, Phases 1-4 have been developed. Phase 8 is now being proposed for development. General Note: According to the latest Preliminary Plat of the subdivision, there will be a total of 460 lots once the development is completed At the request of the City of College Station, the water system is being reanalyzed to verify capacity of the entire system to serve these lots. land Use: Single Family Residential WATER SYSTEM ANALYSIS Design Criteria Primary Water Supply: Domestic Demand: Avg. Pop Density: Existing 12" line along Graham Road 2.67 people per lot Average Flow: Peaking Factor: 100 gpd/cap or 267 gpd per lot = 0.18 gpm per lot 4 Peak Flow: Design Flow: Fire Demand: 0.74 gpm per lot 1.50 gpm per lot Fire Flow: 1000 gpm Hydrant Number: 81-31 in Phase 8 Pipe: PVC DR-14 C909 Roughness Coeff: 150 (Hazen Williams) Hydraulic Software: Haestad Methods WaterCAD v.6.0 Existing City System Pressure Tests Flow Hydrant #: Q-036 Flowrate: 1500 gpm Static Hydrant #: S-023 Static Pressure: 91 psi (210 ft water) Residual Pressure: 89 psi (206 ft water) Applicable Exhibits: Exhibit A -Water System Schematic Exhibit B -Flow Test Report Water System Summary As Criteria I Required I i ! Designed Min. Pressure -fire (psi) Max. Velocity (fps) Max. Length of 6" pipe (ft) (connected to~ 8 "on both ends) Max Length of 6 "pipe (ft) (not connected on both ends) Max. Length of 3 "pipe (ft) 20 12 1500 800 500 Applicable Exhibits: Conclusion Exhibit C -Junction Summary for Fire Flows Exhibit D -Pipe Summary for Fire Flows 87.06 4.82 853 160 169 l ocation lJ-6 l P-30 8P-34 4P-72 I P-73 The proposed water system for Dove Crossing Subdivision, Phases 1-9 has been designed to meet all criteria from the B/CS Design Standards. The system pressure in th e city lin es along Graham Road are very high due to the proximity of the nearby water tower and the large lines running from it. The analysis above indicates the Dove Crossing system will fa r exceed the minimum perfonnance requirements ofTCEQ and the City of College Stati on. I I II , --- I M ·-· -.. , Graham Road L ' ':;-_ u -<"> " 's-5> "U I ~ " ~ (.. ! / TP-'29·;: w -4 Whitcwing La& 3 ; I ...... J "'Q , -, ~v i~ ; \-:>6' " 's-v, 'V> / x .,,. .J id. ,,. ' /, ;.. < ;: _§ ~ ric tJ \ E U' -" '/ ! ·~ " IP-7 !P-8 v/ ;: IP-76 ' > 'U v, ~ i ).--.... 0 " 0 I \\! Crystal Dove Avenue v'.<i ~ v, "' 6'_, <D ~ 3 15= 00 <. "' <" -/ -2P-ll 2P-10 -~ " " · ~rtlc uo~.-T o1<1 ..!.. Turtle Dove Trail ~ v, u , " '.s> ~.,,. 'v, w ~ ~ 6' v, I:> 6' / s; <D A w "U "U "' "U :i ~ 6' I ::; ..!.. -0 ii> SP-70 v, "' "' S'6' "' " A ..) "U > v, V1 I i 4P-20 3bg 1 3P-15 3P-16 3P-17 8P-18 "' <D u -; Dc:Wc,Landing Avenue> "S! "'v Dove Landing Avenu'e' v, ..) ·rn Dove Landing Avenue Iv ..) _J "U -~ y v. v> _§ '.;> "s-/6' I -"' < w ~ ' -Ul "U 2 I I -;;c .,,. IV Mki w Alk") ~ 0 ,,.v, 1 0 i' <".;i '.,, S' 6' "' ~ A v, v, ~ 4P-7> A 4P-23 0 ·~ "U SP-31 S'._,, <".s; 8P-34 v: I ~En en\!'ct-Dove A venue ~ "' Emerald Dove A VP'"''" ~6' w Emerald Dove Avenue o>v, b m "' "' 0 .<;" >. 12 0 I ... A ~ ~ ~ < >< "U "U )> I I I "1 -, -i m ~ A ~ ~ m 0 i <D I -~ 3 ::i::i ::i::i I " 0 i ii 6P-50 S'-4 SP-47 SP-46 9P-45 9P-44 u (/) ~ . >. . "'.I -< (/) " OW.£ Run Trail .f v, u ove Kun I ra11 -v,, v,, Dove Run Trilll v,, ~ /' (/) (/) " ~ ..)<" -i --.2 "' '>§ v _,, -O' m z 0 "' "' ~ ~ $ G) OJ :r: "U ,_ "U " I < I ~ ~ (/) (/) > Ul .!:! Ul c 0 "' 6: -g "' > f\ 0 -6'v 0 .s> OJ v, v I 0 -1 6' .,,..,,. "' 6P-54 6~ "' 7P-63 > V!i ~ 'V> )'& P-75 m < "U "U 9P-40 .s>, v s:: -, .s> - .,,.v ~ Dove Chase Lane y' Ul uove LJ1ase Lane .j>S' ... Dove Chase Lane "'.,,. ~ v, )> (/) . Ul '::::l -i "U ''U 6'_, 0 0 )> I I z I Ul I I 6P-7 ~ " 6P-58 Ul 7P-60 7P-61 9P-64 '°-• 9p_?j I v, ~ v V's-" 6' 6' Eal(le A venue's-. ~ v v .,,._ . - 1601 GRAHAM ROAD COLLEGE STATION TEXAS 77845 Date: 6 AUGUST 2004 Number pages including cover sheet -I Fax to: 764-7759 Attention: JOE SCHULTZ Company: TEXCON From: Butch Willis Water Wastewater Division Phone: 979-764-3435 Fax: 979-764-3452 FLOW TEST REPORT Nozzle size: 2.5 inch Location: GRAHAM RD Flow hydrant number: Q-036 Pl.tot reading: 80 (GPM): 1500 Static hydrant number: S-023 Static PSI: 91 Residual PSI: 89 NOTE: This is the one you handed us this morning Exhibit 8 Exhibit C Dove Crossing Subdivision , Phases 1-9 Water System Analysis Junction Summary Label Elevation Demand Hydr~uli~ . I Pressure Grade I ·---i (ft) (gpm) (ft) (psi) 1 J-1 302 0.0 508.55 I 89.49 1 J-11 305 27.0 509.05 88.24 1 J-12 305 0.0 508.99 88.26 1J-2 302 6.0 508.53 89.53 1J-24 303 15.0 508.98 89.12 1J-25 304 27.0 509.06 88.72 1J-26 307 3.0 510.08 87.78 1 J-27 306 0.0 511.36 88.85 1J-3 300 6.0 508.79 90.29 1J-4 307 33.0 509.57 87.55 1J-5 308 30.0 510.43 87.58 1J-59 297 4.5 508.77 91.54 1J-6 308 0.0 509.68 87.06 1J-61 300 0.0 508.53 90.26 1J-7 308 25.5 509.65 87.07 1J-8 307 33.0 509.00 87.57 2J-10 303 30.0 508.43 88.88 2J-9 298 7.5 507.99 90.81 3J-13 300 21 .0 508.62 90.22 3J-14 300 18.0 507.80 90.12 3J-15 297 16.5 507.19 9Q.94 3J-16 291 22.5 507.16 93.52 3J-18 301 0.0 508.62 90.04 3J-53 292 0.0 507.21 93.33 4J-19 299 22.5 508.62 90.78 4J-20 295 0.0 508.34 92.52 4J-21 294 39.0 508.32 92.77 4J-22 293 18.0 508.32 93.07 4J-23 296 4.5 508.45 92.13 4J-58 294 0.0 508.32 92.64 5J-28 294 42.0 507.15 92.44 5J-29 294 0.0 507.15 92.22 5J-37 290 21.0 507.16 93.82 5J-39 290 18.0 507.57 94.05 5J-40 291 21.0 508.16 94.13 5J-41 290 0.0 508.16 94.26 6J-42 292 21 .0 508.16 93.74 6J-43 292 15.0 508.08 93.53 6J-44 292 7.5 508.08 93.66 6J-45 286 19.5 508.08 96.08 6J-46 290 0.0 508.08 94.35 6J-47 290 12.0 508.06 94.56 6J-48 284 9.5 508.06 96.94 6J-60 290 0 .0 508.06 94.26 Page 1 of 2 Exhibit C Dove Crossing Subdivision, Phases 1-9 Water System Analysis Junction Summary Label Elevation Demand Hydraulic Pressure Grade (ft) (gpm) (ft) (psi) 7J-35 288 30.0 507.24 94.90 7J-36 288 0.0 507.23 94.81 7J-50 287 9.0 507.68 95.57 7J-51 287 7.5 507.37 95.34 8J-17 298 6.0 505.37 89.93 8J-30 295 9.0 504.50 90.81 8J-31 295 1,001 .5 I 504.42 90.65 8J-54 300 0.0 505.37 89.05 8J-55 300 4.5 505.37 89.07 8J-56 300 0.0 505.37 88.85 9J-32 291 6.0 505.05 92.69 9J-33 287 0.0 505.19 94.49 9J-34 287 3.0 505.21 94.62 9J-38 289 21 .0 505.91 93.76 9J-52 286 6.0 507.37 95.78 9J-57 286 0.0 507.37 95.99 9J-61 287 0.0 505.21 94.32 Lowest Pressure in Phase 8 = 88.85 psi Lowest Pressure in System = 87.06 psi Page 2 of 2 Exhibit D Water System Analysis Pipe Summary Dove Cross ing Subdivision , Phases 1-9 Length Diameter Material Hazen-Discharge Velocity Label ' (ft) (in) Williams C (gpm} (ftls) 1 P-1 18 8 PVC 150 251.97 1.61 1 P-13 41 12 PVC 150 898.61 2.55 1 P-2 221 8 PVC 150 -251 .97 1.61 1 P-27 59 6 PVC 150 -136.64 I 1.55 1 P-28 511 6 PVC 150 -163.64 1.86 1 P-29 173 6 PVC 150 -166.64 1.89 1 P-3 663 8 PVC 150 -262.47 I 1.68 1P-30 179 12 PVC 150 -1,699.50 I 4.82 1P-4 592 8 PVC 150 -295.47 1.89 1 P-5 274 12 PVC 150 1,207.39 3.43 1P-6 11 12 PVC 150 1,207.39 3.43 1 P-67 375 6 PVC 150 17.88 0.20 1P-7 505 6 PVC 150 128.79 1.46 1P-73 169 3 PVC 150 4.50 0.20 1P-76 161 8 PVC 150 0.00 0.00 1 P-8 646 6 PVC 150 95.79 1.09 2P-10 575 6 PVC 150 -97.50 1 .11 2P-11 499 6 PVC 150 -127.50 1.45 2P-12 278 12 PVC 150 -1 ,053.10 2.99 2P-66 262 8 PVC 150 I -431.75 I 2.76 2P-9 280 8 PVC 150 341.75 2.18 3P-14 239 12 PVC 150 880.72 2.50 3P-15 389 6 PVC 150 169.33 1.92 3P-16 354 6 PVC 150 151.33 1.72 3P-17 333 8 PVC 150 59.40 0.38 3P-19 70 6 PVC 150 -3.51 0.04 3P-21 287 12 PVC 150 693.91 1.97 3P-33 287 8 PVC 150 -75.43 0.48 3P-65 18 8 PVC 150 -431.75 2.76 4P-20 304 6 PVC 150 -3.51 0.04 4P-22 18 12 PVC 150 693.91 1.97 4P-23 376 6 PVC 150 -6.97 0.08 4P-24 133 6 PVC 150 -109.01 1.24 4P-25 173 6 PVC 150 -113.51 1.29 4P-26 239 6 PVC 150 -139.53 1.58 4P-48 280 12 PVC 150 -517.86 1.4 7 4P-51 280 6 PVC 150 -84.04 0.95 4P-72 160 6 PVC 150 0.00 0.00 5P-31 744 6 PVC 150 144.02 1.63 5P-32 18 8 PVC 150 -75.43 0.48 5P-42 263 8 PVC 150 122.31 0.78 5P-43 279 8 PVC 150 30.56 0.20 5P-46 354 6 PVC 150 -122.93 1.39 Page 1 of 2 Exhibit D Water System Analysis Pipe Summary Dove Crossing Subdivision, Phases 1-9 --,--------~a~eria~ T Hazen-Discharge Velocity Label L_~gth , . _Dia~_:t:_r _ Williams C , ____ - (ft) (in) (gpm) (fUs) 5P-47 389 6 PVC 150 -140.93 1.60 5P-49 70 6 PVC 150 -4 .01 0.05 6P-50 304 6 PVC 150 -4 .01 0.05 6P-52 262 6 PVC 150 59.03 0.67 6P-53 18 6 PVC 150 44.03 0.50 6P-54 375 6 PVC 150 3.83 0.04 6P-55 18 12 PVC 150 -359.94 1.02 6P-56 262 12 PVC 150 -359.94 1.02 6P-57 166 6 PVC 150 32.70 0.37 6P-58 376 8 PVC 150 20.70 0.13 6P-59 165 12 PVC 150 -223.8 1 0.63 6P-74 160 8 PVC 150 0.00 0.00 7P-41 18 8 PVC 150 122.31 0.78 7P-60 389 8 PVC 150 235.01 1.50 7P-61 354 8 PVC 150 226.01 1.44 7P-62 165 8 PVC 150 212.51 1.36 7P-63 744 6 PVC 150 120.46 1.37 8P-18 521 8 PVC 150 468.65 2.99 8P-34 853 6 PVC 150 208.00 2.36 8P-35 18 8 PVC 150 543.35 3.47 8P-36 287 8 PVC 150 -458.15 2.92 8P-37 280 8 PVC 150 344.34 2.20 8P-68 140 8 PVC 150 4.50 0.03 8P-69 15 8 PVC 150 0.00 0.00 8P-70 156 8 PVC 150 0.00 0.00 9P-38 259 8 PVC 150 -177.66 1.13 9P-39 21 8 PVC 150 -177.66 1.13 9P-40 849 6 PVC 150 -180.66 2.05 9P-44 394 6 PVC 150 -1 72.68 1.96 9P-45 457 6 PVC 150 -193.68 2.20 9P-64 344 8 PVC 150 6.00 0.04 9P-71 188 8 PVC 150 0.00 0.00 9P-75 156 6 PVC 150 0.00 0.00 Highest Velocity = 4.82 fps Page 2 of 2 iA C1vIL DEVELOPMENT, Ltd. iA CIVIL ENGINEERING & DESIGN-BUILD SERVICES P.O. Box 11929 · College Station, Texas 77842 · Phone: 979-764-7743 · September 1 7, 2007 Carol Cotter Development Services City of College Station College Station, Texas RE: ADDENDUM TOW ATER REPORT DOVE CROSSING SUBDIVISION, PHASE 8 COLLEGE STATION, TEXAS Dear Carol: Fax: 979-764-7759 ·,~etcP (VO er~ In response to your concern regarding the flow characteristics of the Dove Crossing Water System, I revised the computer model of the system to include only the lines in Phases 1-4 and those proposed in Phase 8. Following is a summary of the results. Water System Summary Criteria i Required As Location Designed Min. Pressure -fire (psi) 20 86.60 81-56 Max. Velocity (fps) 12 4.82 2P-66 Max. Length of 6 "pipe (ft) 1500 853 8P-34 (connected to 2:. 8 "on both ends) Max Length of 6" pipe (ft) 800 160 4P-72 (not connected on both ends) Max. Length of 3 "pipe (ft) 500 169 lP-73 The minimum pressure in the revised model is only about 0.5 psi lower than th e minimum pressure in the entire Dove Crossing System will be once it is full y constructed. The maximum pipe velocity changed from 4.82 fps to 4.80 fps. While these new minimums are in different pipe and junction lo cations, the system responded to the fire demand in a very simil ar manner. This has been my experience on most other water systems in College Station, particularly since the new design guidelines have come into effect. Please feel free to contact me if you have questions. Kent Laza, P.E. Project Manager I ~ ..>'. 0 :i:; I 1, i_ I 1/ i~ Grah~m Road _L, " "" J'V'.si ~ ~ :> fl .< c!i j:;j -Whitewing La -~.j.: ' I~ 'V' v ':<i 0-./ ~ I I'\ !!:1-0 " 0 I v .. ---IP-7 IP 1 e b ) \\"1 cry .. 1 "'"' ,.,,,, 'o '." i,,-./v~~ ' .. ' -8 ru co .,~ ~I (" .~ '., _ 2P-11 , 2P-10 gjj ./ ) lr(\rtle uo11c-T1:2L<1 J: Turtle Dove Trail ~ v, u '.si v ... "'v, vu ..., ~ 'P glj ~ W I 1' ~1' dJ' n.> ,.... -(]' <1' ij ~ V> • > v ./v 0 @..., .n '" 00 I ...,..Vv_ ""U ~~ f P-70 t @v'.J<S 8P-18 _ 3~~1 3P-15 3P-16 3P-17 ~ _ <1' 00 4P-?O 3P· 3P-16 3P-17 " . ~ Do¥c;Landing Avenut?~ "'v Dove Landing Avenue v,; .;> vi~ Dove Landing Avenue ~.., : " -is, ".;> , v. ./ ~ ft'> 0 I -\5' cS 'B ~ <( ~ ~ 'I I I I ~( Jl' 1v Alky ~ A1ky (t. ~ .:.v'--.... ir , ., a '-----' ;~~Ji 8P-34 @vl 1 ' ,j[ Emorald ~"'""" l Dove Run I rad Dove Run Trail :?: v -"' ~ Emerafri,J2ove Avenue I("' RooTmil lj( ] [ ] "-------<( I<----; I I Dove Chase Lane uove Clli:i~c Lane Dove Chase Lane I----" ( )( J __ Eagle Avenue i~ / ; LJ"' 4~ '( .... . ·"' ~ 0 0 < m rn 0 :;;,;: ::u >< )> 0 --i (/) rn (/) I ::u z (/) G) -< (/) -(/) c OJ rri OJ s: g (/) :s -0 (/) -I I 0 rn s: _z I )> ""() )> --i :::T 0 __. .J,. Qo CXl Exhibit B Dove Crossing Subdivision, Phases 1,2,3,4,8 Water System Analysis Junction Summary Label Elevation Demand Hydraulic Pressure Grade - (ft) (gpm) (ft) (psi) 1 J-1 302 0.0 507 .69 89.12 1 J-11 305 27.0 510.55 88.88 1J-12 305 0.0 510 .53 88.92 1J-2 302 6.0 507.65 89.15 1J-24 303 15.0 510 .54 89.79 1 J-25 304 27.0 510 .57 89.37 1J-26 307 3.0 511 .10 88.22 1J-27 306 0.0 511.99 89 .1 2 1J-3 300 6.0 508.17 90.02 1J-4 307 33.0 509.69 87.61 1J-5 308 30.0 511.28 87.95 1J-59 297 4.5 508.16 91.27 1J-6 308 0.0 510.83 87.56 1J-61 300 0.0 507.65 89 .88 1J-7 308 25.5 510.81 87.57 1J-8 307 33.0 509.18 87.65 2J-10 303 30.0 508.37 88.86 2J-9 298 7.5 506.40 90 .12 3J-1 3 300 21 .0 510.44 91.01 3J-14 300 18.0 506.97 89.76 3J-15 297 16.5 504.08 89.59 3J-16 291 22.5 504.08 92.19 3J-18 301 0.0 510.45 90.83 3J-53 292 0.0 504.23 92.04 4J-19 299 22.5 510.46 91.57 4J-20 295 0.0 510.44 93 .43 4J-21 294 39.0 510.44 93.69 4J-22 293 18.0 510.44 93.99 4J-23 296 4.5 510.45 93 .00 4J-58 294 0.0 510.44 93.56 8FH-29 294 0.0 503 .51 90.65 8FH-31 295 1,001 .5 498.05 87.89 8J-17 298 6.0 500.16 87.68 8J-28 294 42.0 503.48 90.85 8J-30 295 9.0 498.08 88.04 8J-54 300 0.0 500.16 86.79 8J-55 300 4.5 500.16 86 .81 8J-56 300 0.0 500.16 86.60 Lowest Pressure in Phase 8 = 86.60 psi Lowest Pressure in System= 86.60 psi Page 1 of 1 Exhibit C Water System Analysis Pipe Summary Dove Crossing Subdivision, Phases 1,2,3,4,8 Label f Length I (ft) 1 P-1 18 1 P-13 41 1P-2 221 1 P-27 59 1P-28 511 1 P-29 173 1 P-3 663 1 P-30 179 1 P-4 592 1 P-5 274 1 P-6 11 1 P-67 375 1P-7 505 1 P-73 169 1P-76 161 1 P-8 646 2P-1 0 575 2P-11 499 2P-12 278 2P-66 262 2P-9 280 3P-14 239 3P-15 389 3P-16 354 3P-17 333 3P-19 70 3P-21 287 3P-33 287 3P-65 18 4P-20 304 4P-22 18 4P-23 376 4P-24 133 4P-25 173 4P-26 239 4P-72 160 8P-18 521 8P-32 18 8P-34 853 8P-35 18 SP-36 287 SP-68 140 8P-69 15 8P-70 156 Diameter (in) 8 12 8 6 6 6 8 12 8 12 12 6 6 3 8 6 6 6 12 8 8 12 6 6 8 6 12 8 8 6 12 6 6 6 6 6 8 8 6 8 8 8 8 8 Material PVC PVC PVC PVC PVC PVC PVC PVC PVC PVC PVC PVC PVC PVC PVC PVC PVC PVC PVC PVC PVC PVC PVC PVC PVC PVC PVC PVC PVC PVC PVC PVC PVC PVC PVC PVC PVC PVC PVC PVC PVC PVC PVC PVC Hazen- Williams C 150 150 150 150 150 150 150 150 150 150 150 150 150 150 150 150 150 150 150 150 150 150 150 150 150 150 150 150 150 150 150 150 150 150 150 150 150 150 150 150 150 150 150 150 Discharge Velocity -; (gpm) (fUs) 366.1 1 2.34 400.96 1.14 -366.11 2.34 -87 .17 0.99 -114.17 1.30 -117.17 1.33 -376.61 2.40 -1,472.50 4.18 -409.61 2.61 915.73 2.60 915.73 2.60 -9.31 0.11 212.57 2.41 4.50 0.20 0.00 0.00 179.57 2.04 -219. 70 2.49 -249.70 2.83 -677 .66 1.92 -751.88 4.80 539.68 3.44 410.26 1.16 368.12 4.18 350.12 3.97 -13.91 0.09 -17.63 0.20 38.77 0.11 -347.54 2.22 -751 .88 4.80 -17.63 0.20 38 .77 0.11 -0.23 0.00 -18.23 0.21 -22.73 0.26 -62.86 0.71 0.00 0.00 715.46 4.57 -347.54 2.22 305.54 3.47 296.54 1.89 -704 .96 4.50 4.50 0.03 0.00 0.00 0.00 0.00 Highest Velocity = 4.80 fps Page 1 of 1 Response to Staff Review Comments No. 2 Dove Cro ssin g Subdivision, Phase 8 Engineering comments dated 711712007 Engineering 1. I realize that the Fire Flow Report was previously approved with Phase 1; however, the flow requirements have changed to 1000 gpm per hydrant in residential subdivisions. As this is a health and safety issue, provide an addendum to the report showing that the system meets current flow requirements as thi s is what will be tested for in the field prior to acceptance. Response: A new water system analysis was pe1formed on the entire Dove Crossing Subdivision (Phases 1-9). It is included with this submittal. 2. As now phased, does the existing system with the addition of Phase 8 meet fire flow requirements? Response: The water system analysis indicates the fire flow requirements are easily met in Phase 8. 3. For the temporary turnaround as proposed on the construction plans, a temporary public access easement will need to be dedicated by separate instrument. Striping and or signage will also be required to prevent parking in turnaround . Response: A easement dedication application is included with this submittal for the area around the turnaround. Also, No-Parking Signs have been added to the plans (Sheet 3) to prohibit parking in that area.