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HomeMy WebLinkAboutFolderFOR OFFICE USE ONLY P&Z Case No.: --'f)""'--3_--_,_,/ 53-=----- Date Submitted: ( O .., ~O -0 ~ FINAL PLAT APPLICATION 7)P4f-03_;6/ (Check one) 0 Amending ($300.00) 0' Final ($400.00) 0 Vacating ($400.00) 0 Replat ($600.00)* *Includes public hearing fee The following items must be submitted by an established filing deadline date for P&Z Commission consideration. MINIMUM SUBMITTAL REQUIREMENTS: ~ Filing Fee (see above) NOTE: Multiple Sheets -$55.00 per additional sheet Variance Request to Subdivision Regulations -$100 (if applicable) B Development Permit Application Fee of $200.00 (if applicable). g--Infrastructure Inspection Fee of $600.00 (applicable if any public infrastructure is being constructed) G" Application completed in full. 8'". Thirteen (13) folded copies of plat. (A signed mylar original must be submitted after staff review.) 0 One (1) copy of the approved Preliminary Plat and/or one (1) Master Plan (if applicable). B Paid tax certificates from City of College Station, Brazos County and College Station l.S.D. B" A copy of the attached checklist with all items checked off or a brief explanation as to why they are not. 0" Two (2) copies of public infrastructure plans associated with this plat (if applicable). Parkland Dedication requirement approved by the Parks & Recreation Board, please provide proof of approval (if applicable). NAME OF SUBDIVISION -Ste--h'iJYI / 2 SPECIFIED LOCATION OF PRO PO ED SUBDIVISION (Lot & Block) v..x:st o( S,t./. fa on 6-em-s f@irTL Re APPLICANT/PROJECT MANAGER'S INFORMATION (Primary Contact for the Project): Name 6rem5 {ralrie ~l/C;sfo(~ LtJ-~ hhlia.aPiuLLlp5 Street Address LflfL[O (0.sfugciU fr1V~ _ City U lfl1J '[tah tm State TX Zip Code _J_,_1--'--'<tll~S'------ Phone Number (C/71) ftf!O -]7J5D Fax Number (C/?l) 010-/o4{ CURRENT PROPERTY OWNER'S INFORMATION: (6!! owners must be identified. Please attach an additional sheet, if necessary) Name &eevis Pralrfe, In vtsfvys Lid . Street Address 44}0 Gl"t>1l()~aii Qr( Vu City CoU f fi ~th/\ state 'JR. Zip code 17B'ts= Phone Numier Jjjf) lftO -]?hD Fax Number _....{c-+-1_._7q.._,,)L->mh'--"ft ...... ~_-_._9-+-7_.._q_._] __ _ ARCHITECT OR ~N<(INEER'S INFORMATION: Name Joe ~ulf-t>.B~. -1ek.cr>n E·Mai1 joe.schuJke-b.cen-nif Street Address )JD] tlr-aba.wi Road City (o(le~ $fad:i~ state _____.tK-+-'>o~)--Zip Code :r1't:ffj- Phone Numoer . Ji]i)Jdij{)-11 l ( -Fax Number _.C....,_f_:._7..L..,f ......... ) &;~fil~--+CC-1-74-1-4-] __ _ 1-Aug-02 1of5 Acreage Total Property jJ, 353 Total# Of Lots JtD R-0-W Acreage {-7l2 ~ · Existing Use: Vac_d.flf Proposed Use: '&1¥ --fWruJ rf5tdLf1i/~ __ f Number Of Lots By Zoning District l1il_ I J?QU_-t--J __ I __ I __ Average Acreage Of Each Residential Lot By Zoning District: o.r~21 rurJ _,_ _,_ / __ Floodplain Acreage 7, 0 5 CJ..£re-S A Statement Addressing Any Differences Between The Final Plat And Approved Master Development Plan And/Or Preliminary Plat (If Applicable): /J, Requested Variances To Subdivision Regulations & Reason For Same: _p..._....71t_D_-~tf~_1:l;>~n_~{~...___...,,__ ___ _ RequestedOversizeParticipation: __ n_n~n_e_L~--------------------~ Total Linear Footage of Parkland Dedication due prior to filing the Final Plat: Proposed Public: ·Ati,.,.f I TIV Streets ACREAGE: {rreViDUS (.y dedieated) __ # of acres to be dedidted + $__ development fee ~1c....' -::7 -./ Sidewalks 3(1-' 3£o' ?!Co' Sanitary Sewer Lines Water Lines Channels -Flu.me/~ Storm Sewers Bike Lanes I Paths __ # of acres in floodplain # of acres in detention __ # of acres in greenways OR FEE IN LIEU OF LAND: #of Single-Family Dwelling Units X $556 = $ __ __ (date) Approved by Parks & Recreation Board NOTE: DIGITAL COPY OF PLAT MUST BE SUBMITTED PRIOR TO FILING. The applicant has prepared this application and certifies that the facts stated herein and exhibits attached hereto are true, correct and complete. The undersigned hereby requests approval by the City of College Station of the above-identified final plat and attests that this request does not amend any covenants or restrictions associated with this plat . .dd4t@ ~ Signature and~ ~ -F" /?-o3 1-Aug-02 2 of 5 SUPPLEMENTAL DEVELOPMENT PERMIT INFORMATION Application is~ hereby made for the ~ecific site/waterway alterations: ACKNOWLEDGMENTS: (Aj().//a?e Pful/t/S I, __ , design engineer/9wner, hereby acknowledge or affirm that: The information and conclusions 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 1: of the College Station City Code. M.t&a ~4-.-'.WA.<.LNA Property Owner($) ~-' Contractor CERTIFICATIONS: (for proposed alterations within designated flood hazard areas.) A. I, certify that any nonresidential structure on or proposed to be on this site as part of this applicatior is designated to prevent damage to the structure or its contents as a result of flooding from the 100 yea ~orm. · Engineer Date B. I, certify that the finished floor elevation of the lowest floor, including any basement, of an: res idential structure, proposed as part of this application is at or above the base flood elevation established ir the latest Federal Insurance Administration Flood Hazard Study and maps, as amended. Engineer ~~~ Date J '1 p ~-'~\, C. I, D5£f , c~rt!!fll'tJl·i~W~s or development covered by this permit shall not diminish the fiood carrying capacit sf.-ihe rw~ ii\ioining or crossing this permitted site and that such alterations a development ar * • ·6ta ·th.m'1Jjjr,~ents of the City of College Station City Code, Chapter 13 concernin~ encroachments s. .. J.~Jg~way fringes. ~~~~!.!...:::~~~~~···~~~~~~'~ ~~h_·_l_1_~_o~~~~~~~~~~ \~toN;~··~~~-Date °'\.~-- D. I, , 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 Hazard Study. Engineer Da.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 b1 taken to insure that debris from construction, erosion, and sedimentation shall not be deposited in city street~ or existing drainage facilities. All development shall be in accordance with the plans and specification submitted to and approved by the City Engineer for the above named project. All of the applicable codes ani ordinances of the City of College Station shall apply. 1-Aug-02 3 or 5 SUBMIT APPLICATION ANO THIS LIST CHECKED OFF WITH 13 FOLDED COPIES OF PLAT FOR REVIEW FINAL PLAT MINIMUM REQUIREMENTS (ALL CITY ORDINANCES MUST BE MET) INCLUDING BUT NOT LIMITED TO THE FOLLOWING: (Requirements based on field survey and marked by monuments and markers.) G-1. Drawn on 24" x 36" sheet to scale of 100' per inch or larger. G 2. Vicinity map wh ich includes enough of surrounding area to show general location of subject property in relationship to College Station and its City Limits. No scale required but include north arrow. 0 1-Aug-02 3. 4. 5. 6. 7. Title Block with the following information: [3 er Name and address of subdivider, recorded owner, planner, engineer and surveyor. Proposed name of subdivision . (Subdivision name & street names will be approved through Brazos County 911 .) (Replats need to retain original subdivision name.) C( Date of preparation. G Engineer's scale in feet. G Total area intended to be developed. North Arrow. Subdivision boundary indicated by heavy lines. If more than 1 sheet, an index sheet showing entire subdivision at a scale of 500 feet per inch or larger. All applicable certifications based on the type of final plat. IT Ownership and Dedication [f Surveyor and/or Engineer Gr City Engineer (and City Planner, if a minor plat) ~ Planning and Zoning Commission (delete if minor plat) U Brazos County Clerk .{) Brazos County Commissioners Court Approval (ET J Plats only) 8. Paid tax certificates. 9. If submitting a replat where there are existing improvements, submit a survey of the subjecl property showing the improvements to ensure that no encroachments will be created. 10. If using private septic systems, add a general note on the plat that no private sewage facility ma) be installed on any lot in this subdivision without the issuance of a license by the Brazos Count) Health Unit under the provisions of the private facility regulations adopted by the Commissioner'l: Court of Brazos County, pursuant to the provisions of Section 21 .004 of the Texas Water Code. 11 . Location of the 100 Year Floodplain and floodway, if applicable, according to the most receff available data. 12. Lot corner markers and survey monuments (by symbol) and clearly tied to basic survey data. 13. Matches the approved preliminary plat and/or master development plan. 4 of 5 14. The location and description with accurate dimensions, bearings or deflection angles and radii area, center angle, degree of curvature, tangent distance and length of all curves for all of th~ following: (Show existing items that are intersecting or contiguous with the boundary of or forming a boundary with the subdivision, as well as, those within the subdivision). Existing ProROSed cf Streets. Continuous or end in a cul-de-sac, stubbed out streets must end into a temp turn around unless they are shorter than 100 feet. c1 d Public and private R.O .W. locations and widths. (All existing and proposed R.O.W.'s sufficient to meet Thoroughfare Plan.) Street offsets and/or intersection angles meet ordinance. Alleys . Easements. A number or letter to identify each lot or site and each block. Greenbelt area/park linkages/parkland dedication ( All proposed dedications must be reviewed by the Parks and Recreation Board prior to P & Z Commission consideration.) c( 15. Construction documents for all public infrastructure drawn on 24" x 36" sheets and properly sealed by a Licensed Texas Professional Engineer that include the following: G Street, alley and sidewalk plans, profiles and sections. One sheet must show the overall rr street, alley and/or sidewalk layout of the subdivision. (may be combined with other utilities). Sanitary sewer plan and profile showing depth and grades. One sheet must show the overall sewer layout of the subdivision. (Utilities of sufficient size/depth to meet the utility master plan and any future growth areas.) Water line plan showing fire hydrants, valves, etc. with plan and profile lines showing depth and grades. One sheet must show the overall water layout of ·the subdivision. (Utilities of sufficient size/depth to meet the utility master plan and any future growth areas.) B" Storm drainage system plan with contours, street profile, inlets, storm sewer and drainage channels, with profiles and sections. Drainage and runoff areas, and runoff based on 5, 10, 25, 50 and 100 year rain intensity. Detailed drainage structure design, ,· cjlannel lining design & detention if used. One sheet must show the overall drainage .$u~'~yout of the subdivision. ~~o' Detailed cost estimates for all public infrastructure listed above sealed by Texas P.E. tfA! B' Drainage Report. 0' 16. m 17. . 6 18. NOTE: 1. 2. 1-Aug-02 ~ Erosion Control Plan (must be included in construction plans). All off-site easements necessary for infrastructure construction must be shown on the final plat with a volume and page listed to indicate where the separate instrument easements were filed . Separate instrument easements must be filed prior or concurrently with Final Plat. Are there impact fees associated with this development? r(Yes D No Impact fees for R-1, R-2, & R-3 zoned final plats, must be paid prior to filing . Will any construction occur in TexDOT rights-of-way? D Yes 01\Jo If yes, TexDOT permit must be submitted along with the construction documents. We will be requesting the corrected Final Plat to be submitted in digital form if available prior to filing the plat at the Courthouse. If the construction area is greater than 5 acres, EPA Notice of Intent (NOi) must be submitted prior to issuance of a development permit. 5 or 5 TAX CERTIFICATE Certificate # 30635 This certificate issued by for the taxing entities: Brazos County (Gl) College Station City <C2> Through 2002 Tax Vear College Station ISO <S2> Property ID: R107719 Owner ID: 160865 Recount Num: 005401-0002-0020 A005401 R STEVENSON (ICL>, TRACT 2.2, ACRES 196.2521 GREENS PRAIRIE INVESTORS LTD 4490 CASTLEGATE DR COLLEGE STATION, TX 77845-3388 Assessed Value: 743,800 No exemptions This document is to certify that after a careful check of the tax records of this office, the following current or delinquent taxes, penalties, and interest are due on the property for the taxing entities described above: Entity Vear State1ent C2 Gl S2 03 RB394 03 RB394 03 RB394 Total \\\\\\1111111////// '!<.,,,, cou. 11111. ~'\; ~\J Ecr, :t~ ~ n..~ ••••••••• o~ ~ ~ '"'~ • •, ~r ~ ~LJ.J: ""T '·--''E. =C/)• ·':P= fi ..... ~l-•• •• ~~ -(f)· •><-~4::, r-~ :l:Js % ·.. s ... i ~ ·. .· ~ Due Tax Due 1,460.54 1,341.22 5, 718. 54 on All Bills Disc./P&I Att. Fee 0.00 0.00 0.00 0.00 0.00 0.00 if Paid By 06/30/2003: C2 Taxes Paid for 2002: Gl Taxes Paid for 2002: S2 Taxes Paid for 2002: Total Due 1,460.54 1, 341. 22 5,718.54 $8,520.30 u 1, 933. 60 $10,968.75 $46,702.17 ~ <9. •• •• -1 §. ~ ~1 ........ ~,-<...'~ ~,,,,, .?os co\}'~,,,~ ~,,,,,,,, 1111111'''' SPECIAL CONDITIONS EXIST ON THIS ACCOUNT, SEE BELOW This certificate is issued on real estate only. It does not include minerals and/or personal property. *** End of Tax Certificate *** If applicable, the above described property is rece1v1ng special valuation based on its use. Additional rollback taxes which may become due based on the provisions of the special valuation are not indicated in this document. This certificate does not clear abuse of granted exe1ptions as defined in Section 11.43, Paragraph Ci) of the Texas Property Tax Code. ~ek. Signature of Authorized Officer of Date of Issue: 06/16/03 Tax Off ice Requested by GREENS PRAIRIE INVESTORS LTD Fee of $10.00 Paid on 06/16/03 by GREENS PRAIRIE INVESTORS LTD Page 1 DEVELOPMENT PERMIT PERMIT NO. 03-51 ~-v Project: Castlegate Subdivision Section 12 COlllGl STATION FOR AREAS INSIDE THE SPECIAL FLOOD HAZARD AREA RE: CHAPTER 13 OF THE COLLEGE STATION CITY CODE SITE LEGAL DESCRIPTION: CASTELGATE SECTION 12 ALL LOTS DATE OF ISSUE: 8/6/03 OWNER: GREENS PRAIRIE INVESTORS LTD 4490 CASTLE GA TE DR COLLEGE STATION, TX 77845 SITE ADDRESS: CASTELGATE SUBDIVISION DRAINAGE BASIN: Spring Creek VALID FOR 12 MONTHS CONTRACTOR: TEXCON GENERAL CONTRACTORS 1707 GRAHAM ROAD COLLEGE STATION, TX 77845 TYPE OF DEVELOPMENT: Full Development Permit SPECIAL CONDITIONS: All construction must be in compliance with the approved construction plans All trees must be barricaded, as shown on plans , prior to any construction . Any trees not barricaded will not count towards landscaping points . Barricades must be 1' per caliper inch of the tree diameter. Erosion control per the approved plans must be in place for duration of the project. The Contractor shall take all necessary precautions to prevent silt and debris from leaving the immediate construction site in accordance with the approved erosion control plan as well as the City of College Station Drainage Policy and Design Criteria. If it is determined the prescribed erosion control measures are ineffective to retain all sediment onsite, it is the contractors responsibility to implement measures that will meet City, State and Federal requirements. The Owner and/or Contractor shall assure that all disturbed areas are sodden and establishment of vegetation occurs prior to removal of any silt fencing or hay bales used for temporary erosion control. The Owner and/or Contractor shall also insure that any disturbed vegetation be returned to its original condition, placement and state. The Owner and/or Contractor shall be responsible for any damage to adjacent properties, city streets or infrastructure due to heavy machinery and/or equipment as well as erosion, siltation or sedimentation resulting from the permitted work. Any trees required to be protected by ordinance or as part of the landscape plan must be completely fenced before any operations of this permit can begin. In accordance with Chapter 13 of the Code of Ordinances of the City of College Station, measures sha ll 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 inside 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 of the codes and ordinances of the City of Colle e Station that apply. Date D j1-o/--W Date TEXCON GENERAL CONTRACTORS 03-Jul-03 CONSTRUCTION COST ESTIMATE CASTLEGATE SUBDIVISION COLLEGE STATION, TEXAS SECTION 12 -40 LOTS Item Estimated Unit Estimated No. Description Quantity Price Cost Sitework Mobilization/Layout 1.0 LS $10,000.00 $10,000 2 Site Preparation 1.7 AC $3,000.00 $5,100 3 Topsoil Stripping & Replacement 750 CY $4 .50 $3,375 4 Sediment & Erosion Control 1 LS $5,000.00 $5,000 5 Excavation 2,000 CY $3.50 $7,000 6 Lime Stabilized Subgrade 5,140 SY $3.25 -$16,705 7 Concrete Curb & Gutter 2,775 LF $8.00 $22,200 8 Base Material -6" depth 4,140 SY $6.00 $24,840 9 Asphalt Paving -1 1 /2" depth 4,140 SY $5.00 $20,700 10 Concrete Apron 1,100 SF $5.50 $6,050 11 ADA Ramp -corner 2 EA $450.00 $900 12 Concrete Sidewalk -4' wide 2,290 SF $3.00 $6,870 13 Seeding & Hydromulch 8,000 SY $0.50 $4.000 Subtotal $132,740 Storm Drainage 14 Drainage Pipe -24" RCP -structural 107 LF $45.00 $4,815 15 Drainage Pipe -36" RCP -structural 30 LF $63.00 $1 ,890 16 Drainage Pipe -36" RCP -non-structural 242 LF $55.00 $13,310 17 Headwall -36" RCP 1 EA $3,000.00 $3,000 18 Inlets 5' wide I Junction boxes 2 EA $2,400.00 $4,800 19 Inlets 10' wide EA $3,200.00 $3,200 20 Rock riprap 40 TN $50.00 $2,000 21 Concrete drainage flume 844 SF $5.00 $4,220 Subtotal $37,235 Water Lines 22 6" Water PVC CL200 (C900) structural 185 LF $26.00 $4,810 23 6" Water PVC CL200 (C900) non-structural 565 LF $20.00 $11,300 24 8" Water PVC CL200 (C900) structural 525 LF $30.00 $15,750 25 8" Water PVC CL200 (C900) non-structural 90 LF $25.00 $2,250 26 Gate Valves -6" 2 EA $500.00 $1,000 27 Gate Valves -8" 2 EA $600.00 $1,200 28 M.J. Tees -6" 2 EA $350.00 $700 29 M.J. Tees -8" 2 EA $400.00 $800 30 M.J. Reducer -8" x 6" 2 EA $300.00 $600 31 M.J. Bend -6" 11.25 deg. 3 EA $300.00 $900 32 M.J. Bend -8" 11.25 deg. 4 EA $350.00 $1,400 33 Water Services 21 EA $750.00 $15,750 34 2" Blow off Assembly 2 EA $450.00 $900 35 Fire Hydrant Assembly 2 EA $2,200.00 $4,400 36 Connect to existing line 2 EA $350.00 $700 Subtotal $62,460 Sanitary Sewer Lines 37 6" SOR 26 Pipe -structural 80 LF $30.00 $2,400 38 6" SOR 26 Pipe -non-structural 240 LF $20.00 $4,800 39 Services -connect to existing stack pipe 17 EA $350.00 $5,950 40 Sewer Services 7 EA $750.00 $5,250 41 Manholes -average deg,,U!..~~~~~\\ EA $2,200.00 $2,200 42 Connect to existing~"\ E. OF /~ \~\ EA $250.00 $250 ~" .. * .. .r.., 1, Subtotal $20,850 ;" •• •• •• •• tS' t ".. .. · ... ,, Total Sitework $132,740 ~*: ···~ ~·············--····················'I., Total Storm Drainage $37,235 1. JOSEPH P. CHU Tl it. Total Water $62,460 I':······ .. ···"· .......... ~1>\ 5 .' Total Sanitary Sewer 20 850 . . TOTAL CONSTRUCTION $253,285 ••• ST •• •• '~ ; Engineering and Survey @ 6% $15,197 .s ........ ..,;.0 .,, \~ONAL E. ___ Contingency @ 5% $12,664 "'~-TOTALj $281,146J 7--3 ~o3 Page 1 ol 1 Drainage Report for Castlegate Subdivision -Section 12 College Station, Texas June 2003 Developer: Greens Prairie Investors, Ltd. By Greens Prairie Associates, LLC 4490 Castlegate Drive College Station, Texas 77845 (979) 690-7250 Prepared By: TEXCON General Contractors 1 707 Graham Road Coll ege Station, Texas 77845 (979) 690-77 1 1 EV I EWE "'nl.I"' JUL 0 2 2003~ COu.cu~ : TION ENGINEERING CERTIFICATION I, Joseph P. Schultz, Li censed Professional Engineer No. 65889, State o f Texas, certi fy that thi s report for th e drainage desi gn for th e Castlegate Subdivision -Section 12, was prepared by me in accordance with the provi sions of th e C ity of Coll ege S tati on Drainage Policy and Design Standards fo r th e owners hereof. ~~Ur&?= ~o ,P .E. TABLE O F CO NTENTS DRAINAGE RE PORT CASTLEGATE SUBDIVISION -SECTION 12 C ERTIFICATIO TABLE OF CONT ENTS ....................................................................................................................................................... 2 LIST 0 FT ABLES .................................................................................................................................................................. 2 INTRODUCTION .................................................................................................................................................................. 3 GE ERAL LOCATION AND DESCRIPTION ................................................................................................................. 3 FLOOD HAZARD INFORJVIATION ................................................................................................................................... 3 DEVE LOPMENT DRAINAGE PATTERNS ...................................................................................................................... 3 DRAINAGE DESIGN C RITERIA ....................................................................................................................................... 4 STORM "YATER RUN O FF DETERMINATION .............................................................................................................. 4 DETE TION FACILITY DESIG ..................................................................................................................................... 5 STORM SE \VER & FLUME DESIGN ................................................................................................................................ 5 CONCLUSIONS ..................................................................................................................................................................... 6 APPENDIX A ......................................................................................................................................................................... 7 Storm Sewer Inlet Desig 11 Calculatio11s APPE DIX B ........................................................................................................................................................................ 10 Storm Sewer Pipe Design Calculations APPE NDIX C ....................................................................................................................................................................... 17 Drai11age Flume Calc11latio11s EXHIBIT A ........................................................................................................................................................................... 20 Post-Development Drai11age A rea Map LIST O F TABLES TABLE 1 -Rain fa ll In tensity Calculations .......................................................................................... 4 TABLE 2 -Post-Development Runoff Information -Storm Sewer Des ign ..................................... 5 INTROD UCTION DRAINAGE REPORT CASTLEGATE SUBDIVISION -SECTION 12 The purpose of thi s report is to provid e the hydrological effects of the construction of the Castlegate Subdivision -S ection 12, and to veri fy that the proposed stonn drainage system meets the requirements set forth by the City of Coll ege Station Drainage Poli cy and Design Standards. GENERAL LOCATION AND DESCRIPTION The project is located on a portion of a 111 .46 acre tract located west of State Highway 6 along the north side of Greens Prairie Road in College Station, Texas. This report addresses Section 12 of this subdi vision, which is made up of 17.353 acres. Section 12 is located east of Victoria Avenue and Castlegate Section 11 . The site is predominantly pastureland w ith approximately 10% of the area wooded. The ex isti ng ground elevations range from elevation 292 to e levation 310. The general location of the project site is shown on the vicinity map in Exhibit A. FLOOD HAZARD INFORMATION The project site is located in the Spring Creek branch of the Lick Creek Drainage Basin. Most of the proposed developed area of the site is located in a Zone X Area according to the Flood Insurance Rate Map prepared by the Federal Emergency Management Agency (FEMA) for Brazos County, Texas and incorporated areas dated February 9, 2000, panel number 48041 C0205-D. Some of the proposed residential lots are partially in Special Flood Hazard Area, Zone AE, as shown on the panel. This area is shown on Exhibit A as the 100-year floodplain limit. Also shown on this exhibit are the floodplain limits as determined by the Castlegate Floodplain Analysis Report which was previously submitted. The rear portions of some of the residential lots in Section 12 are within the 100-year flo odplai n limits. However, the floodplain limit detennined by the Castlegate Floodplain Analysis results in less of the lot area being in the F lood Hazard Area. The majority of the F lood Hazard Area has been designated as Common Area, which will have no development and it will be left in its current condition. DEVELOPMENT DRAINAGE PATTERNS Prior to development, the storm water runoff for Section 12 flows in an easterly direction until it enters a tributary of Sprin g Creek. Stom1 water runoff from Castl egate Section 11 and Victoria Avenue is captured by the Section 11 storm system and ro uted through Section 12. Ultimately, the runoff flows into Sprin g Creek and th en north to the proposed regional detention faci lity. Refer to th e vici nity map in Ex hibi t A fo r the location of thi s regional detention fac ili ty. DRAlNAGE DESIGN CRITERIA The design parameters fo r the storm sewer are as follows: • The Rational Method is utilized to determine peak storm water runoff rates for the storm sewer design. • Design Storn1 Frequenc y Storn1 Sewer system • Runoff Coefficients Pre-development 10 and 100-year sto 1111 events Post-development (single family residential) c = 0.30 c = 0.55 • Rainfall Intensity values for Brazos County for a minimum time of concentration of l 0 minutes can be found in Table 1. Where a longer time of concentration was necessary, it is noted in the respective table, and the intensities are calculated with the hi gher val ues where required. • Time of Concentration, tc -Due to th e small sizes of the drainage areas, most of the calcul ated times of concentration, tc, are less than l 0 minutes. Therefore, a minimum tc of 10 minutes is used in most cases to detern1ine the rainfall intensity values. Where a longer time of concentration was necessary, it is noted and used accordingly. STORM WATER RUNOFF DETERMINATION The peak runoff values were determined in accordance with the criteria presented in the previous section for the 5, 10, 25, 50, and l 00-year storn1 events. The runoff coefficients are based on the future development of this tract. The drainage areas for post-development are shown on Exhibit A. Post-development runoff conditions for the storn1 sewer design are summarized in Table 2. The runoff data for existing Pipe 3 can be found in the Drainage Report for Castl egate Section 11. TABLE 1 -Rainfall Intensity Calcul ations Rainfall Intensity Values {in/hr) Storm t = c Event 10 min Is 7.693 110 8.635 125 9.861 lso 11 .148 1100 11 .639 Brazos County: 5 'i_ear storm 10 'i_ear storm b = 76 b = 80 d = 8.5 d = 8.5 e = 0.785 e = 0.763 I = b I (tc+d)0 I = Rainfall Intensity (in/hr) tc = L/(V*60) tc =Time of concentration (IT)in) L = Length {ft) V = Velocity (ft/sec) 25 'i_ear storm 50 'i_ear storm 100 'i_ear storm b = 89 b = 98 b = 96 d = 8.5 d = 8.5 d = 8.0 e = 0.754 e = 0.745 e = 0.730 (Data taken from State Department of Highwa'i_S and Public Transportation H'i_draulic Manual , pag e 2-16) TABLE 2 -Post-Development Runoff Information -Storm Sewer Des ign Area c 5 year storm 10 year storm 25 year storm 50 year storm 100 year stor le lso Oso 1100 Area# (acres) Is Os 110 0 10 l2s 0 2s C1 C2 Crotal (in/hr) (cfs) (in/hr) A1 A2 Total (min) (in/hr) (cfs) (in/hr) (cfs) (in/hr) (cfs) Section 11 (Refer lo Section 11 Drainage Report) 37.19 ---------------------12-1 0.72 0 0.72 0.55 0.3 0.55 10 7.693 3 05 8.635 3.42 9.861 3.91 11 .148 4.41 11 .639 -----------------·--------------12-2 0.14 0 0.14 0.55 0.3 0.55 10 7.693 0.59 8.635 0.66 9.861 0.76 11 .148 0.86 11 .639 12-3 1.87 0 1.87 0.55 0.3 0.55 10 7.693 7.91 8.635 8.88 9.861 10.14 11.148 11.47 11 .639 -f---------------12-4 0.57 0 0.57 0.55 0.3 0.55 10 7.693 2.4 1 8.635 2.71 9.861 3.09 11 .148 3.49 11 .639 ------------------12-5 1.79 0 1.79 0.55 0.3 0.55 10 7.693 7.57 8.635 8.50 9.861 9.71 11 .148 10.97 11 .639 --12-6 0.34 0 0.34 0.55 0.3 0.55 10 7.693 1.44 8.635 1.61 9.861 1.84 11 .148 2.08 11 .639 The Rational Method: Q=CIA I = b I (tc+d)" Q =Flow (cfs) A= Area (acre s) C = Runoff Coeff. le = Time of concentration (min) tc = L/(V*60) L = Length (ft V =Velocity (ft/sec) I = Rainfall Intensity (in/hr) Brazos County: 5 year storm b = 76 d = 8.5 e = 0.79 10 year storm b = 80 d = 8.5 e = 0.76 DETENTION FACILITY DESIGN 25 year storm 50 yea r storm 100 year storm b = 89 b = 98 b = 96 d = 8.5 d = 8.5 d = 8.0 e = 0.75 e = 0.745 e = 0.730 The detention facility handling the runoff from thi s site is a regional facility designed by LIA Engin eering & Surveying, Inc. Also, a detention pond was constructed upstream of Cast legate Dri ve to reduce the peak tlow resulting from the Castlegate development. Refer to the vicinity map in Exhibit A for the locations of the regional detention faci lity and the detention pond upstream of Castlegate Drive. The runoff from this project flows into existing drainages and then into Spring Creek. The detention facility is located adjacent to Sp1ing Creek prior to Spring Creek entering the State Highway 6 ri ght-of-way. STORM SE\VER & FLUME DESIGN The stonn sewer piping for this project has been se lected to be Reinforced Concrete Pipe (RCP) meeting th e requirements of ASTM C-76, Class III pipe meetin g the requirements of ASTM C-789. Th e curb inl ets and junction bo xes wi ll be cast-i n-pl ace concrete. Appendix A presents a summary of th e storm sewer inl et des ign parameters and calculations. Th e inl ets were des igned based on a I 0-year design storm . As per Coll ege Stati on guid eli nes, th e capaciti es of inlets in sump were reduced by I 0% to allow for clogging. Inl ets for the residenti al streets were located to maintain a gutter fl ow depth of 5" or less. Thi s design depth wi 11 prevent th e spread of water from reaching the crown of the roa d for th e I 0- year storm event. Refer to Appendix A for a summ ary of the gutter flow depth s. The runoff intercepted by th e proposed storm sewer inl ets was ca lcul ated using th e fo llowing eq uation s. The depth of fl ow in the gut ter was determined by using the Straight Crow n Flow eq uat ion . The flo w intercepted by Inl ets 11 04 & I I 05 was calcul ated by using the Capa cit y of Inl ets On 0 10 (cf~ 50.1 ,___ 4.6 --0.9' 11 .~ 3.6 >---11.£ 2.1 Grade equation. These equations and the resulting data are also summarized in Appendix A. There are no inl ets in sump proposed for thi s phase of development. Appendix B presents a summary of the stom1 sewer pipe desi gn parameters and calc ul ations. A ll pipes are 18" in di ameter or larger. For pipes with 18" a nd 24" diameters, the cross- sectional area is reduced by 25%, as per Coll ege Station requirements. A summary of how thi s was achi eved is shown in Appendi x Bas well. The pipes for th e storm sewer system were designed based on the 10-year storm event, and they will a lso pass the 100-year stom1 event without th e headwater exceeding the top of the road. Based on the depth of flow in the street determined for the 100-year stom1 event, this runoff will be contained within the street ri ght-of- way until it enters the stom1 sewer system. As required by College Station, the velocity of flow in the storm sewer pipe system is not lo wer than 2.5 feet per second , and it does not exceed 15 feet per second. As the data shows, even during low flow conditions, the velocity in the pipes will exceed 2.5 feet per second and prevent sediment build-up in the pipes. The maximum flow in the stonn sewer pipe system will occur in Pipe No. I. The maximum velocity for th e pipe system in this development will be 8.5 feet per second and w ill occur in Pipe No. 2. Appendi x B contains a s ummary of the pipe calcul ations as well as fl ow diagrams mapping the fl ows through the storm sewer system for the 10 and 100-year events. There are two drainage flumes proposed for this development. Refer to Exhibit A for the lo cations of F lume Nos. 1 & 2. Flume No. I will have a bottom width of 4', and it w ill be 8" in depth. Flu me No. 2 will have a bottom width of 5', and it will also be 8" in depth. The slope of both flumes wi ll be 2.5%. The resulting velociti es for Flume No. I will be 5.3 fps for the I 0-year storm and 5.9 fps for the 100-year storm. The resulting velociti es for Flume No. 2 will be 7.6 fps for the 10-year stom1 and 8.8 fps fo r the 100-year stom1 . Rock riprap will be placed at the end of the flumes to dissipate the energy and control erosion. Appendix C presents a summary of the flume design parameters and calculations. The flumes were designed based on a 10-year design storm, and they pass the 100-year stom1 event as well. CONCLUSIONS The construction of this project will increase the storm water runoff from this site. The proposed storm sewer system should adequately control th e runoff and release it into existing drainages. As shown in the Castlegate Floodplain Analysis, the Castlegate Subdivision does not have a significant effect on the 100-year floodplain water surface elevations or the floodplain limits. Also, the regional detention faci lity should adequately control the peak post- development runoff so that it will not have any impact on th e properties downstream of the Crowley Tract. APPENDIX A Storm Sewer Inlet Design Calculations 7 Castlegate Subdivision Section 12 Inlet Length Calculations Inlets On Grade 10 year storm Inlet# 1104 1105 Flowlrom y,, Length I Area# (ft) (in) 10' 12-3 041q_I 4.92 5' 12-4 0.243 2.92 Transverse (Crown) slope (ftlftl for residential streets= 0.033 O pertoot Oupaclt Obyp.1ss (ft) (els) (els) 0.70 7.03 1.71 ---0.54 2.71 -0.76 Straight Crow n Flow (Solved to find actual depth of flow, yl: a= o.56 • (z/n) • s 112 • y8" Q y =(Qt [0.56 • (z/n) • s 112n"' n = Roughness Coefficient= 0.018 S = StreeVGutter Slope (fVft) y = Depth of flow at inlet (ft) Capacity of Inlets on grade: Oc = 0.7 • [1/(H, -H2)]" [H,"2-H2512] Oc = Flow capacity of inlet (els) H1 =a + y H2 = a =gutter depression (2" Standard; 4" Recessed) y = Depth of flow in approach gutter (ft) O uptUfed (els) 7.03 1.95 Ocarryover Obyp-tota O u1p1-to«1 010.Totat Y100 apet ,oot (els) I from inlet# (els) (els) (els) (ft) I (in) (ft) I 1.71 7.03 8.74 0.458 _1* 0.75 I 0.00 1.95 1.95 0.272 3.27 0.57 z = Reciprocal of crown slope for residential streets = 30 Inlets in sumps, Weir Flow: L =QI (3 • y312) Q y = (QI 3L)213 L = Length of inlet opening (ft) Q = Flow at inlet (els) y = total depth of flow on inlet (ft) max y for inlet in sump = 7" = 0. 583' 100 year storm Oup.1dty Obyp.1u Oc•ptured O coutyover Obyp.tot•• Oup1.tot1 Q100·Total 5 LKhhll (els) (els) (els) ( cfs) I from inlet 1 (els) (els) (els) (ftlft) (ft) 7.53 4.25 7.53 I 4.25 7.53 11.78 0.0100 10 --I-------------2.84 -0.22 2.62 0.00 2.62 2.62 0.0080 5 Castlegate Subdivision -Section 12 Depth of Flow in Street Gutter & Drainage Flumes Depth of Flow -Street Gutter 10-year storm 100-year storm Gutter A c Slope a,. Y10-aclual a, •• Y1 00 Location (acres) (ftlft) (els) (ft) (in) (els) (ft) E1 0.64 0.55 0.008 3.04 0.288 3.45 4.10 0.322 E2 1.84 0.55 0.010 8.74 0.410 4.92 11 .78 0.458 ·E3 1.49 0.55 0.010 8.78 0.411 4.93 13.79 0.486 F1 0.12 0.55 0.008 0.57 0.154 1.84 0 77 0.172 --------- F2 0.41 0.55 0.008 1.95 0.243 2.92 2.62 0.272 --------------------- F3 0.17 0.55 0.010 0.81 0.168 2.01 1.09 0.188 • Includes bypass fiow from Inlet 11 04 Transverse (Crown) slope (ft/ft) for residential streets = 0.0330 Straight Crown Flow (Solved to find actual depth of flow in gutter, y): Q = 0.56 * (z/n) * 5112 * y813 <=:> y ={Q I [0.56 * (z/n) * 5112]}318 n = Roughness Coefficient 0.018 S = Street/Gutter Slope (ft/ft) y = Depth of flow at inlet (ft) z = Reciprocal of crown slope: for residential streets = 30 Note: For the residential streets, laydown curb is used, therefore, th e maximum allowable depth of flow in the gutter for th e 10-year storm event is 5". Depth of Flow -Drainage Flumes 10-year storm (in) 3.86 5.50 5.84 2 06 3.27 -- 2.25 Location Area# Total A c 0 10 Ocarry over 0 10.Total Y10.-actual Nos. (acres) (els) (els) I from inlet # (els) (ft) (in) 12-1 0 -Flume No. 1 --0.86 0.55 4.08 4.08 0.192 2.30 12-2 0 - Flume No. 12-5 1.71 Inlet 1104 2 ---1.95 0.55 9.26 10.97 0.358 4.30 12-6 0.00 Inlet 1105 100-year storm a, •• Ocarry over 0100-Tolal Y100 (els) (els) I from inlet# (els) (ft) (in) 0 I 5.51 5.51 0.233 2.80 0 4.25 I Inlet 1104 12.48 16.73 0.475 5.70 0.00 I Inlet 11 05 APPENDIXB Storm Sewer Pipe Design Calculations 10 Castlegate Subdivision S f 12 p· C I I f ec ion -1:>e a cu a ions Inlet Outlet 10 year storm 100 year storm Pipe/Box# Size Length Slope Invert Elev Invert Elev *Actual Flow Design Flow V 10 % Full Travel Time, tno *Actual Flow Design Flow V 100 (in) (ft) (%) (ft) (ft) (cfs) (cfs) (fps) (sec) (min) (cfs) (cfs) (fps) .. 1 36 241.4 0.65 292.40 290.83 46.17 8.0 76.0 30 0.50 60.27 ------·-.. 2 36 30.0 0.60 292.68 292.50 44.22 7.7 75.7 4 0.06 57.65 .. 6 24 106.4 0.80 295.75 294.90 7.03 11 .35 6.3 56.1 17 0.28 7.53 12.16 "These values reflect the actual flow for the 18" & 24" pipes. The design flow for these pipe sizes reflects a 25 % reduction 1n pipe area. (Refer to attached calculation for specific information .) ··Pipe 1 Headwater (for 0 100) = 297.46, Top of curb= 299.39 Pipe 2 Headwater (for 0 100) = 298.96, Top of curb= 299.33 Pipe 6 Headwater (for 0 100) = 299.59, Top of curb= 300.00 8.5 -- 8.2 3.9 % Full - - - Travel Time, tT1oo (sec) (min) 28 0.47 ---4 0.06 27 0.45 City of College Station requirement to Reduce Cross-Sectional Area of 18" & 24" Pipes by 25% Using Mannings Equation from page 48 of the College Station Drainage Policy & Design Standards Manual: Q = 1.49/n *A* R213 * S112 Q = Flow Capacity (cfs) 18" Pipe: Pipe size (inches) = 18 Wetted Perimeter WP, (ft) = 4.71 Cross-Sectional Area A, (ft2) = 1.766 Reduced Area AR, (ft2) = 1 .325 Hydraulic Radius R =A/WP, (ft) = 0.375 Reduced Hydr Radius RR= ARNVp. (ft) = 0.281 Roughness Coefficient n = 0.014 Friction Slope of Conduit S1, (ft/ft) = 0.01 Example Calculation: Slope Flow Capacity Reduced Flow Capacity % Difference s Q Oreduced OreduceiO 0.005 6.91 4.28 0.619 -0.006 7.57 4.69 0.619 -·---0.007 8.18 5.06 0.619 24" Pipe: Pipe size (inches) = 24 Wetted Perimeter WP, (ft) = 6.28 Cross-Sectional Area A, (ft2) = 3.14 Reduced Area AR, (ft2) = 2.355 Hydraulic Radius R =A/WP, (ft) = 0.5 Reduced Hydr Radius RR = ARNVp. (ft) = 0.375 Roughness Coefficient n = 0.014 Friction Slope of Conduit S1, (ft/ft) = 0.01 Example Calculation: Slope Flow Capacity Reduced Flow Capacity % Difference s Q Oreduced OreduceiO 0.005 14.89 9.22 0.619 --·---0.006 16.31 10.1 0.619 -----0.007 17.61 10.9 0.619 Conclusion: Multiply actual Qin 18" & 24" pipes by 1.615 to reflect a 25% reduction in the cross-sectional area called for on page 47, paragraph 5 of the College Station Drainage Policy & Design Standards manual. Castlegate Subdivision Section 12 -Pipe Flow Diagrams 0 10 (cfs) From Sect. 11 ' I 37.19 J, Inlet 1104 7.03 Junction Box 3 J, J, Pipe 6 I 7.03 I I Pipe 2 I 44.22 J, Inlet 1105 I 1.95 J, Pipe 1 46 .17 J, II into Spring Crk I 46.2 II 0 100 (cfs) From Sect. 11 I 50 .12 J, Inlet 1104 1 7.53 Junction Box 3 J, J, Pipe 6 I 7.53 Pipe 2 57.65 J, In let 1105 , 2.62 J, Pipe 1 I 60.27 ' J, IJ 1nto Spring Crk 60.3 JI Pipe 1 -10 Year Storm Manning Pipe Ca l c u lator Given Input Data: Shape ........ . Solving for . Diameter Flowrate ........... . Slope .................. . Ma nning's n ............ . Computed Results: Depth ...... . Area ......... . Wetted Area ........ . Wetted Perimeter ....... . Perimeter . . . . . . . . . . . . . . . . ..... . Ve l ocity .............. . Hydraulic Radius .. . Percent Ful l ...... . Full flow Flowrate ........ . Fu ll flow vel ocity ............. . Circular Depth of Flow 36.0000 in 46.2000 cfs 0.0065 ft/ft 0.0140 27.3448 in 7 .0686 ft2 5.7608 ft2 76.1998 in 113.0973 in 8.0197 fps 10.8867 in 75.9578 % 49.9330 cfs 7.0641 fps Pipe 1 -100 Year Storm Culvert Calculator Entered Data: Shape .................. . Number of Barrels ...... . Sol ving for . . . . . . . . . . . . . . ..... . Chart Number ................... . Scale Number ................... . Chart Description .............. . Scale Descri ption .............. . Overtopping .................... . Flowrate . . . . . . . . . . . . . . . ...... . Manning's n ............ . Roadway Elevation ..... . Inlet Elevation ....... . Outlet Elevation ...... . Diameter .............. . Length ................ . Entrance Loss . Tailwater ..... Computed Results: Headwater ... . Slope ........ . Velocity ........... . Cas tlega t e Subdiv i sion -Section 12 College Stat ion , Texas Circular 1 Headwat er 1 1 CONCRETE PIPE CULVERT; NO BEVELED RING ENTRANCE SQUARE EDGE ENTRANCE WITH HEADWALL Off 60 .3000 cfs 0.0140 299.3900 ft 292.4000 ft 290.8300 ft 36.0000 in 241.4000 ft 0.2000 3.0000 ft 297.4644 ft Outlet Control 0.0065 ft /ft 8 .5307 fp s Pipe 2 -10 Year Storm Manning Pipe Calculator Given Input Data: Shape ...... . Solving for . Diameter Flowrate ................. . Slope . . . . . . . ............ . Manning's n . Computed Results: Depth .......................... · Area ............ . Wetted Area .... . Wetted Perimeter ..... . Perimeter ................. . Velocity .................. . Hydraulic Radius ............ . Percent Full ................... . Full flow Flowrate ............. . Full flow velocity ............. . Circular Depth of Flow 36.0000 in 44.2200 cfs 0 .0060 ft/ft 0.0140 27.2539 in 7.0686 ft2 5.7414 ft2 75.9873 in 113 . 0973 in 7.7020 fps 10.8802 in 75.7051 % 47.9740 cfs 6.7869 fps Pipe 2 -100 Year Storm Culvert Calculator Entered Data: Shape ...................... . Number of Barrels .......... . Solving for ................ . Chart Number ................... . Scale Number ................ . Chart Descri ption .............. . Scale Description .............. . Overtopping .................... . Flowrate ................... . Manning's n ..... . Roadway Elevation Inlet Elevation .. Outlet Elevation . Diameter ...... . Length .......... . Entrance Loss .............. . Tailwater .................. . Computed Results: Headwater Slope .... Velocity . Cas legate Subd iv i sion -Se ction J 2 College Station , Texas Circular 1 Headwater 1 1 CONCRETE PIPE CULVERT; NO BEVELED RING ENTRANCE SQUARE EDGE ENTRANCE WITH HEADWALL Off 57.7000 cfs 0.0140 299.3300 ft 292 .6800 ft 292.5000 ft 36.0000 in 30 .0000 ft 0 .2000 4.9600 ft 298 .9617 ft Outlet Control 0 .006 0 ft/ft 8.1629 fps Pipe 6 -10 Year Storm Manning Pipe Calculator Given Input Data: Shape ..... . Solving for Diameter Flowrate ......... . Slope ..... . Manning's n . Computed Results: Depth ...... . Area ........ . Wetted Area .. Wetted Perimeter ............... . Perimeter ...................... . Velocity ....................... . Hydraulic Radius . . . .... . Percent Full . . . . . . . .... . Full flow Flowrate ...... . Full flow velocity ............. . Circular Depth of Flow 24.0000 in 11.3500 cfs 0.0080 ft/ft 0.0140 13. 4556 in 3.1416 ft2 1.8128 ft2 40.6174 in 75 .3982 in 6.2611 fps 6.4269 in 56.0649 % 18.7888 cfs 5.9807 fps Pipe 6 -100 Yea~ Storm Culvert Calculator Entered Data: Shape ....... . Number of Barrels Circular 1 Solving for . . . . . . . . . . . . . . . . . . . . . Headwater Chart Number . . . . . . . . . . . . . . . . . . . . 1 Scale Number ..... Chart Description .... Scale Description . Overtopping .. Flowrate ......... . Manning's n ...... . Roadway Elevation . Inlet Elevation .. . Outlet Elevation ............... . Diameter .... . Length ...... . Entrance Loss Tailwater ... Computed Results : Headwater . Slope ... Velocity .. Castlegate Subdivision -Section 12 College Station , Texas 1 CONCRETE PIPE CULVERT; NO BEVELED RING ENTRANCE SQUARE EDGE ENTRANCE WITH HEADWALL Off 12.1600 cfs 0. 0140 300.0000 ft 295.5000 ft 294.6500 ft 24.0000 in 106.4000 ft 0.2000 4.3100 ft 299.5942 ft Outlet Control 0.0080 ft/ft 3.8706 fps APPENDIX C Drainage Flume Calculations 17 Flume 1 -10 Year Storm Channel Calculator Given Input Data: Shape .......................... . Solving for .................... . Flowrate ....................... . Slope .......................... . Manning' s n .................... . Height ......................... . Bottom width ................... . Computed Results: Depth .......................... . Velocity ....................... . Full Flowrate .................. . Flow area ...................... . Flow perimeter ................. . Hydraulic radius ............... . Top width ...................... . Area ........................... . Perimeter ...................... . Percent full ................... . Rectangular Depth of Flow 4.0800 cfs 0.0250 ft/ft 0.0140 8.0000 in 48.0000 in 2.3198 in 5.2763 fps 28.1931 cfs 0.7733 ft2 52.6396 in 2.1153 in 48.0000 in 2.6667 ft2 64.0000 in 28 .9977 % Flume 1 -100 Year Storm Channel Calculator Given Input Data: Shape .......................... . Sol ving for .................... . Flowrate ....................... . Slope .......................... . Manning' s n .................... . Height ......................... . Bottom width ................... . Computed Results: Depth .......................... . Velocity ....................... . Full Flowrate .................. . Flow area ...................... . Flow perimeter ................. . Hydraulic radius ............... . Top width ...................... . Area ................... . Perimeter ...................... . Percent full ................... . Cas tle gate Subdiv i sion -Sec t ion 12 College Station, Texas Rectangular Depth of Flow 5.5100 cfs 0.0250 ft/ft 0.0140 8.0000 in 48.0000 in 2 .7982 in 5.9074 fps 28.1931 cfs 0.9327 ft2 53.5964 in 2.5060 in 48.0000 in 2.6667 ft2 64.0000 in 34.9774 % Flume 2 -10 Year Storm Channe l Calculator Given Input Data : Shape .......................... . Solving f o r .................... . Flowrate ....................... . Slope .......................... . Manning's n .................... . Height ......................... . Bottom width ................... . Computed Results : Depth .......................... . Ve locity ....................... . Full Flowrate .................. . Flow area ...................... . Flow perimeter ................. . Hydraulic radius ............... . Top width ...................... . Area ........................... . Perimeter ...................... . Percent full ................... . Rectangular Depth of Flow 10 .9700 cfs 0.0250 ft/ft 0.0140 8 .0000 in 48.0000 in 4.3245 in 7.6102 fps 28.1931 cfs 1.4415 ft2 56 .6489 in 3.6642 in 48.0000 in 2.6667 ft2 64 .0000 in 54 .0559 % Flume 2 -100 Year Storm Channel Calculator Given Input Data : Shape .......................... . Sol ving for .................... . Flowrate ....................... . Slope .......................... . Manning's n .................... . He ight ......................... . Bottom width ................... . Computed Results : Depth .......................... . Velocity ....................... . Full Flowrate .................. . Flow area ...................... . Flow perimeter ................. . Hydraulic radius ............... . Top width ...................... . Area ........................... . Pe rimeter ...................... . Pe rcent full ................... . Castlegate Subdi vision -Section 12 Col lege Stat ion , Te x as Rectangular Depth of Flow 16.7300 cfs 0.0250 ft /ft 0.0140 8 .0000 in 48.0000 in 5 .6755 in 8.8433 fps 28.193 1 cfs 1. 8918 ft2 59.3509 in 4.5900 in 48.0000 in 2.6667 ft2 64.0000 in 70.9432 % EXHIBIT A Post-Development Drainage Area Map 20