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HomeMy WebLinkAboutDrainage Report Drainage Report for CHERRY STREET APARTMENTS COLLEGE STATION, TEXAS February 2015 Owner: CS Second Street Apartments II, LLC 16800 Westgrove Drive, Suite 600 Addison, Texas 75001 Developer: Seneca Investments 16800 Westgrove Drive, Suite 100 Addison, Texas 75001 Prepared By: Schultz Engineering, LLC TBPE Firm No. 12327 P.O. Box 11995 College Station, TX 77842 2730 Longmire Drive, Suite A College Station, Texas 77845 (979) 764-3900 Drainage Report—Executive Summary Cherry Street Apartments College Station,Texas ENGINEER Schultz Engineering, LLC P.O.Box 11995 College Station,Texas 77842 Phone: (979)764—3900 OWNER CS Second Street Apartments II,LLC 16800 Westgrove Drive, Suite 600 Addison,Texas 75001 DEVELOPER Seneca Investments 16800 Westgrove Drive, Suite 100 Addison,Texas 75001 Phone: (214)265-8686 GENERAL DESCRIPTION AND LOCATION This project consists of the redevelopment of Lots 1-8,Block 20 of the W.C.Boyett Estate Partition in College Station,Texas. This NG-3 zoned site project will include the construction of a multi-family building,parking garage,sitework,utilities and other infrastructure. This project is at the corner of Second Street and Cherry Street,as well as,the corner of Cherry Street and Boyett Street. Site Area: 0.901 Existing Land Use:NG-3 Proposed Land Use:NG-3 Number of Lots: 8 Drainage Basin:Burton Creek Watershed FEMA FIRM:#48041C0305F,Dated April 2,2014 Floodplain:None of the development lies within the floodplain. HYDROLOGIC CHARACTERISTICS The pre-development condition of the land was developed with single family and duplex housing and driveways.Exhibit A shows the pre-development and post development drainage areas and the runoff flow direction.The existing flow patterns show that a majority of the property drains southwest toward the Cherry Street/Boyett Street corner,eventually entering the right-of-way being conveyed as surface flow down Boyett Street to a tributary of Burton Creek. Page 1 of 6 Drainage Report—Executive Summary Cherry Street Apartments College Station,Texas GENERAL STORMWATER PLAN The drainage plan for this development will involve the installation of an onsite underground detention facility. The vault will be located under the first level parking garage on the Boyett Street side of the project. The storm water runoff from roof,building and parking garages will be collected and conveyed through the detention facility,refer to the Building Construction Drawings for details on stormwater collection system within the building. The detention facility will have outfall structure on the outside of the structure and discharge into a proposed storm sewer system to be installed in Boyett Street to the Burton Creek Tributary outfall. The proposed detention facility will capture the proposed storm runoff and discharge at a rate equal to or less than the existing design flows. A small portion of the area from the building to the back of curb will bypass the detention facility and discharge directly into the surrounding streets similar to existing flow patterns. The combination of area bypassing the detention facility and the detention facility outflow will be less than or equal to the pre-developed condition for the site. Exhibit B shows the post-development topography and the runoff flow direction. COORDINATION & STORMWATER PERMITTING This site will require a small construction site notice. No other permits are anticipated for this project. DRAINAGE DESIGN General Information: Stormwater runoff from the development will be collected and routed through the detention facility and then discharged into the proposed storm sewer system to be installed in Boyett Street.A portion of the lot,the area between the building and back of curb will bypass the detention facility and discharge directly into the surrounding streets similar to existing flow patterns. The combination of area bypassing the detention facility and the detention facility outflow will be less than or equal to the pre-developed condition for the site. The runoff enters the detention facility from a series of storm sewer pipes and building drain pipes. Detention Facility Analysis Tc Methodology: TR 55 T',Minimum: 10 minutes Design Storm Events: 2-year, 10-year,25-year, 50-year and 100-year detention facility 10-year design& 100-year analysis for public storm sewer system Pond Discharge Pipe &Public Storm Sewer Materials: Class III RCP,Profile Gasket in accordance with ASTM C443,ASTM C76 Manning's n Value: 0.013 Runoff Coefficients: 0.55 for existing conditions,0.92 for developed conditions contributing to detention facility&0.72 for developed conditions contributing directly offsite. Design Constraints: Max.water depth in the parking lot=6 in. or 0.5 ft.for 100 year storm event. Min. flow velocity=2.5 fps Page 2 of 6 Drainage Report—Executive Summary Cherry Street Apartments College Station,Texas Max. flow velocity= 15 fps Post-Development peak runoff less than or equal to existing storm water runoff from the site. Rational Equation: The rational equation is utilized to determine peak storm water runoff rates for the Detention Facility design. Q=CIA Q=Flow(cfs) A=Area(acres) C=Runoff Coefficient I=Rainfall Intensity(in/hr) Design Software: Excel spreadsheets,AutoCAD Hydraflow Express,AutoCAD Hydraflow Hydrographs Extension The software was used to compute the pond storage and discharge data and the pre and post-development peak runoffs and the routing of the flow through the detention facility. The requirement for a 25%reduction in cross sectional area of pipes 24"in diameter or less is achieved by using internal pipe diameters that are less than the standard diameter. The 18"diameter pipe areas were reduced by 25%and a 15.6"diameter pipe was used in the analysis. Design Results: The data presented in the Appendices and in the following tables indicates the detention facility sizing and discharges are in accordance with the requirements of the design guidelines. Refer to Appendix B for design calculations for the storm sewer pipes. Applicable Exhibits: Exhibit A—Pre-development Drainage Area Map Exhibit B—Post-development Drainage Area Map Appendix A—Drainage Area Summary—Detention Facility Appendix B—Pipe Design Summary Appendix C—Detention Facility Data and Hydrographs Design Analysis: The post-development drainage areas are shown on Exhibit B. The design data and descriptions of the detention facility outlet structures,discharge pipes and overflow spillways are found in Appendix C. A portion of site between the building and back of curb will bypass the detention facility and discharge directly into the surrounding streets similar to existing flow patterns. The combination of area bypassing the detention facility and the detention facility outflow will be less than or equal to the pre-developed condition. Sedimentation in the detention facility is not likely due to the small drainage areas that are mostly paved areas and the use of underground detention in storm sewer pipes. However,the design storage capacity of the detention facility was increased by 10%in the event that sediment does build up. The peak flow out of the detention facility was determined by a Storage Routing Analysis based on the Continuity Equation as follows: (I1+I2)+((2s1/dt)- 01)=((2s2/dt)=O2). The time interval,dt,used was 1 minute. The calculations Page 3 of 6 Drainage Report-Executive Summary Cherry Street Apartments College Station, Texas and results of the Storage Routing Analysis were used to generate hydrograph peak flows and graphs for the pre and post development conditions. A summary of the pre and post development runoff information from the site is shown in Table 2. The flow out of the detention facility is controlled by an 8"x 8"orifice and a 3' wide rectangular overflow weir located in the detention facility outlet structure. The rim of the outlet structure grate inlet is 343.94'. The detention facility discharges into a proposed storm sewer system to be installed in Boyett Street. TABLE 1-Pre-&Post-Development Runoff Input Information Tc Area# Area (Acres) C (Min.) Pre 101 1.05 0.55 15 Post 201 0.83 0.92 10 Post 202 0.22 0.72 10 TABLE 2-Pre-&Post-Development Runoff Comparison-Detention Analysis Q2 Q10 Q25 Q50 Q100 Location cfs cfs cfs cfs cfs Pre-Development 3.00 4.15 4.76 5.39 5.62 (Area 101) Post Development with Detention Post-Development 4.83 6.59 7.53 8.51 8.89 (Area 201) Post-Development 1.00 1.37 1.56 1.77 1.84 (Area 202) Detention Facility Outfall 1.94 2.25 2.40 2.55 2.61 (Area 201 Routed Through Facility) Combined Outflow 2.61 3.13 3.40 3.68 3.79 (Compare to Area 101) Decrease in Peak Flow 0.39 1.02 1.36 1.71 1.83 Page 4 of 6 Drainage Report—Executive Summary Cherry Street Apartments College Station,Texas As shown in Table 2,the post-development peak outflow from the project site is less than the allowable peak outflow for each design storm event. Additionally, Tables 3 presents the maximum water surface and the amount of freeboard for the Detention Facility. The peak flow out of the detention facility and the maximum water surface was determined by the Storage Routing Analysis. The proposed 18"diameter storm sewer pipe to be constructed in Boyett Street has a capacity greater than the maximum detention facility discharge rate of 2.61 cfs,as shown in Appendix B. TABLE 3—Summary of Detention Facility Maximum Water Surface Levels Storm Event Peak Flow out of Water Surface Freeboard Facility,(cfs) Elevation,ft. ft. 2-year 1.94 341.22 341.22 10-year 2.25 341.67 341.67 25-year 2.40 341.92 341.92 50-year 2.55 342.19 342.19 100-year 2.61 342.29 342.29 100-year plugged 3.49 342.80 342.80 The 100 year water surface is below the rim elevation of the outfall structure. If the pond outlet orifice clogs,the water will discharge through the 3' wide rectangular overflow weir. If both the orifice and rectangular weir clog the water will discharge through the grate inlet on top of the outlet structure and discharge into the public right of way. CONCLUSION The onsite detention facility for the development will function within the requirements and restrictions of the BCS Drainage Design Guidelines. Page 5 of 6 Drainage Report—Executive Summary Cherry Street Apartments College Station,Texas CERTIFICATION "This report for the drainage design of the Cherry Street Apartments was prepared by me in accordance with the provisions of the Bryan/College Station Unified Drainage Design Guidelines for the owners of the property. All licenses and permits required by any and all state and federal regulatory agencies for the proposed drainage improvements have been issued." /o/IIIIe_- e �-►. L. 1 OF r . Deven L. Doyen,P.E. #r.al �. .* • DEVEN L. DOYEN 109835ew _40..011S 2.1 a I FIRM # 12327 SCHULTZ ENGINEERING, LLC Page 6 of 6 EXHIBIT A Pre-Development Drainage Area Map 1 mi. mow 0 20 40 SCALE IN FEET I I I 1 I l L ` 1 I � a / 1 1 / I r / M / / 4 / / \ / // i ) / L. / / / N.>>b N.0 / A < t �► n_ -1 r 341 J42 • � I Schultz Er SCALE ,�,•; L OP�IE1 X17' EXHIBIT STRONG DLD .4 PA-74 I.r , f-. Week M_4.1 EXHIBIT B Post-Development Drainage Area Map • \ 14'GRATE INLET- 24-5724 © 11111111.1111111 3419!' T MOE , TICK CONORE E EIIEII WALL •CIWICE 1 15.Alm ear •..''�— - ' "ti0 ' .342.30• MII NMI 0 20 40 •��•��4f���41 11 SCALE IN FEET STORM sin ,.._ A41H��4+ �At.+.401 3JY.66' 19.5' imaniiii SECTION B-B HEIGHTVARIER (SEEEMI PLAN FOR SPOT ELEVATIONS) SECTION A-A in WELL "?. 4, 111 PPE 8MM HEIGHT VARIES ' 1�., (SEE PUN FOR SPOT ELEVATIONS)SLOPE . 11111111111111111111111111111111111 1' (SEE 15TRUC URAL PUNS) Y IMP 1wEa 1111111111111111111111111111111111 w � STORY SE1ER SECTION B-R w�_� PA L-6'BUILDING STORM DITNNLdNC STORM DRAIN 8'BUILDING STORM DRAT TO OUTLET SIF ���� A mom. mow DETENTION FACILITY F �w wwE�w..w TOP OF PAVE 01/111111111111111111111111111w BUILDING STORM DRAIN w11111111111wwlw -A 18'STORM SEI wrlIIIIw■Irrllrw TO OUTLET STRUCTI 24•PLATE NET `DETEN110N FAOUTY FLOOR.341.00' I ,0ETENT N FAOUTY FLOOR-; V-6724-1 TOP OF PAVEMENT.344.25' 148.5' MANHI 19.5 TEL 19.5' B L PLAN VIEW L /F DETENTION VAULT PLAN .A 'E'BUILDING I �B'BUILDING STORM GRAIN VIEW DETENTION FAQUTY I TOP OF PAN 2a'PLATE NET TPN FAauTY FLOOR-341.00' V-5724-I TOP OF PAVEMENT.344.25' B I ( v'. i e.Txlac tbNCRETE 1111111111111161.1111111 i��� 'IP. "' ram Cis•ORIFICE SERER r RCP M / STORM SERER I. / a■u . i� / / \ / / \ I.__B PEE WELL DRAW ) / / SECTION A-A. ' -330.55' I / / / DEENTION FACIUTY (..-, / / / UNDERGROUND STRUCTURE E DETAIL / / WI'S. OUTFALL / / / HEADWALL, PIPE 100 1._ ,,• ' ,18" RCP W-1 ' a -! 0 0.40% SLOPE - ' R ST PROPOSED — ST -ST ....... ST �- ST\2 y\'� JUNCTION BOX — -- a y _ ---342,.... --- I I I I I I , Schu-It Ert� SCALE EXHIBIT ...,__ 'L OPMENT VERTICAL SURVEYED DESCRIED 810.7, %r`-- MARK X150! ay DATE STRONG/- --1-- .4REA Ali P APPENDIX A Drainage Area Summary—Detention Facility 9 s w '0 00 0 78 N „ a N M 4 T V 8 1 2 O, .... ..: N Frio 8 77, D` t- :n ao C g 0 4.J, vi oc '» N r.. r.a a > e y II II II ° c a _ .. , -1 - L. rn o0 0 n ? y II II II O 0) R�F 0 M n '^ o aA ^w `D M1 'Oen O O E CI V 1-- N M C r 2 O . y Oe 00 O L y C II II II n .0 .0 a) N ?1:`, O r 'I N °,:, h 00 Q '�°'�" w ,7-; M N r Q O� 7 .O .-+ N M ,i- '..",1.14,,,j' p!r O vl O O, h n .. h 00 00 O .. II II II L b 4, o - h a1 ' ' N .. N 00 00 d f O, 00 O 7, M et .-» ry M L p0 O V1 n _ " 00 00 O II II II a a g .G .v N 'i , O., M M 59 M M b . r urt ,,J' v 1Q 0 o 0 o 8 � .Y ge o 0 i I o b tb a C V 'O 0 V 000 O 44 $ . >.< . 3 ti 00 O p , " N a 7 w II II II C j O i t. O ? L 'O d C U h N N Q y °, : +,�+ g N It 0 0 0 •9 ) F u II it e 4 s 1 d 8 • d � M N N � .o O o0 N a. A 0 a 0 0 fi, $ a d u ro it b ; d 8 2 U y d' Q d �°O 3 v 3 0 a g U .5 [8[� N 0 0 9 0 52 Ii ] !CC a o ;110 N N6 ".9 ¢ 30 0 I v d y 6 �' II it II II II � da. a ` S APPENDIX B Pipe Design Summary 1111111111111111111111111111111111111111111111111111111111111111111111 • or r r r $ I N N- ti 0 0 0 0 N to ,- Lr) LD In M M M M O• 4 co 70 cD co a v. N N N N to U) in U) (D— (D (o co O O O O wMM M M M ... co M M di f N N N La N N N N N C, C i7 N 7 CO N r a o0 0 00 B. r X o 0 v z w w as = m co cd a C) y = = > > Q a e 0 0 0 0 0 c �° Q c c c c cis a a a a°. 0 c • v . v N 0O 0 0 o, 0) v `n C L M (O (D J r 0 CO c cc CO 00 c0 0 • r r r N- 0.a Et: c 0 Z, ,a a E Q r co a)o C ab ,C1 N d `" 0 G C M N r 0 0) d a z 0 0 • 0 O r a O a APPENDIX C Detention Facility Data & Hydrographs t • , Detention Facility Appendix C Detention Facility Summary Detention Facility Design Storm Inflow Outflow W.S. Elevation (yr) (cfs) (cfs) (ft) 2 4.83 1.94 341.22 10 6.59 2.25 341.67 25 7.53 2.40 341.92 50 8.51 2.55 342.19 100 8.89 2.61 342.29 100 Plugged 8.89 3.49 342.80 *Top of outfall structure(overflow grate)=343.94', Weir Crest Elevation=342.30' Detention Facility Appendix C Detention Facility Area-Capacity Data Detention Facility Storage 90% Elevation Depth Volume Cumulative Cumulative Volume Volume (ft) (ft) (ft3) (ft3) (ft3) 339.55 0.00 0 0 0 339.75 0.20 6 5.753 5 340.00 0.45 70 75.79 69 340.25 0.70 203 278.3 253 340.50 0.95 347 624.8 568 340.75 1.20 491 1115.4 1,014 341.00 1.45 635 1750.1 1,591 341.25 1.70 707 2457.4 2,234 341.50 1.95 707 3164.7 2,877 341.75 2.20 , 707 3872 3,520 342.00 2.45 707 4579.3 4,163 342.25 2.70 707 5286.6 4,806 342.50 2.95 707 5993.9 5,449 342.75 3.20 708 6702.3 6,093 343.00 3.45 707 7409.6 6,736 343.25 3.70 708 8118 7,380 Detention Facility Appendix C Elevation-Discharge Data Depth-Discharge Data 8" x 8" 3' Rectangular Facility Orifice Weir Total Design Elevation Depth Flow Spillway Flow (ft) (ft) (cfs) (cfs) (cfs) 339.55 0.0 0.00 0.00 0.00 339.75 0.2 0.04 0.00 0.04 340.00 0.4 0.10 0.00 0.10 340.25 0.7 0.43 0.00 0.43 340.50 0.9 1.21 0.00 1.21 340.75 1.2 1.57 0.00 1.57 341.00 1.4 1.78 0.00 1.78 341.25 1.7 1.97 0.00 1.97 341.50 1.9 2.14 0.00 2.14 341.75 2.2 2.30 0.00 2.30 342.00 2.4 2.45 0.00 2.45 342.25 2.7 2.59 0.00 2.59 342.50 2.9 2.72 0.89 3.61 342.75 3.2 2.85 3.02 5.87 343.00 3.4 2.97 5.85 8.82 343.25 3.7 3.08 9.25 12.33 Notes: 1. The Outlet Structure is a junction box with a 8" x 8" Orifice and a 3'Wide Rectangular Weir 2. The rectangular spillway will serve as the overflow spillway and the outlet structure will have a grate on top for overflow. Detention Facility Plugged Condition The 100 year water surface is below the rim elevations of the outlet structure. If the facility outlet orifice clogs,the water will discharge through the 3'wide rectangular weir. If both the orifice and rectangular weir clog the water will discharge through the grate inlet on top of the outlet structure and discharge into the public right of way. Detention Facility Appendix C Storage Routing Analysis Parameters t=60s Detention Facility Elevation Depth Discharge Storage 2 s/t 2 s/t+O (ft) (ft) (0, cfs) (s, cf) 339.55 0.0 0.00 0.0 0.0 0.00 339.75 0.2 0.04 5.2 0.2 0.21 340.00 0.4 0.10 68.9 2.3 2.40 340.25 0.7 0.43 253.0 8.4 8.86 340.50 0.9 1.21 568.0 18.9 20.14 340.75 1.2 1.57 1014.0 33.8 35.37 341.00 1.4 1.78 1591.0 53.0 54.81 341.25 1.7 1.97 2234.0 74.5 76.44 341.50 1.9 2.14 2877.0 95.9 98.04 341.75 2.2 2.30 3520.0 117.3 119.63 342.00 2.4 2.45 4163.0 138.8 141.22 342.25 2.7 2.59 4806.0 160.2 162.79 342.50 2.9 3.61 5449.0 181.6 185.24 342.75 3.2 5.87 6093.0 203.1 208.97 343.00 3.4 8.82 6736.0 224.5 233.35 343.25 3.7 12.33 7380.0 246.0 258.33 * The flow control structure for the smaller storms is an 8"x8" orifice with a 3'wide rectangular overflow weir. Detention Facility Inflow&Outflow Hydrographs Appendix C Inflow Outflow Inflow Outflow Inflow Outflow Inflow Outflow Inflow Outflow 2yr 2yr l0yr l0yr 25yr 25yr 50yr 50yr 100yr 100yr Time(rain) Q(cfs) Q(cfs) Q(cfs) Q(cfs) Q(cfs) Q(cfs) Q(cfs) Q(cfs) Q(cfs) Q(cfs) 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 1 0.48 0.04 0.66 0.05 0.75 0.05 0.85 0.05 0.89 0.06 2 0.97 0.09 1.32 0.10 1.51 0.11 1.70 0.11 1.78 0.11 3 1.45 0.12 1.98 0.13 2.26 0.14 2.55 0.14 2.67 0.19 4 1.93 0.14 2.64 0.56 3.01 0.68 3.40 0.80 3.56 0.84 5 2.42 0.67 3.30 0.92 3.77 1.04 4.26 1.15 4.44 1.19 6 2.90 0.95 3.96 1.21 4.52 1.30 5.11 1.39 5.33 1.43 7 3.38 1.18 4.62 1.40 5.27 1.49 5.96 1.55 6.22 1.57 8 3.86 1.35 5.27 1.54 6.02 1.60 6.81 1.66 7.11 1.68 9 4.35 1.48 5.93 1.64 6.78 1.71 7.66 1.78 8.00 1.80 10 4.83 1.57 <:6.5'. = 1.73 7.53,-;'=; 1.81 < $.51f-r 1.898.8�°°."= 1.92 11 4.59 1.65 6.26 1.83 7.15 1.91 8.09 2.00 8.44 2.03 12 4.35 1.71 5.93 1.90 6.78 2.00 7.66 2.09 8.00 2.13 13 4.11 1.76 5.60 1.97 6.40 2.07 7.24 2.18 7.55 2.21 14 3.86 1.80 5.27 2.02 6.02 2.13 6.81 2.25 7.11 2.29 15 3.62 1.84 4.94 2.07 5.65 2.19 6.38 2.31 6.67 2.35 16 3.38 1.87 4.62 2.11 5.27 2.24 5.96 2.36 6.22 2.41 17 3.14 1.89 4.29 2.15 4.89 2.28 5.53 2.41 5.78 2.46 18 2.90 1.91 3.96 2.18 4.52 2.31 5.11 2.45 5.33 2.50 19 2.66 1.92 3.63 2.20 4.14 2.34 4.68 2.48 4.89 2.53 20 '1 2.42 1.93 3.30 2.22 3.77 2.36 4.26 2.51 4.44 2.56 21 2.17 1.94 2.97 2.24 3.39 2.38 3.83 2.53 4.00 2.58 22 1.93 1.94 2.64 2.24 3.01 2.39 3.40 2.54 3.56 2.60 23 1.69 a 2.31 _ 2.25y J. 2.64 2.4c<< 2.98 2.55 3.11 2.61: 24 1.45 1.93 1.98 2.25 2.26 2.40 2.55 2.55 2.67 2.61 25 4 1.21 1.92 1.65 2.24 1.88 2.39 2.13 2.55 2.22 2.61 26 0.97 1.91 1.32 2.23 1.51 2.39 1.70 2.54 1.78 2.60 27 4 0.72 1.89 0.99 2.21 1.13 2.37 1.28 2.53 1.33 2.59 28 4 0.48 1.87 0.66 2.19 0.75 2.35 0.85 2.51 0.89 2.57 29 0.24 1.84 0.33 2.17 0.38 2.33 0.43 2.48 0.44 2.54 30 0.00 1.81 0.00 2.14 0.00 2.30 0.00 2.45 0.00 2.51 31 0.00 1.78 0.00 2.10 0.00 2.26 0.00 2.42 0.00 2.48 32 0.00 1.74 0.00 2.07 0.00 2.23 0.00 2.39 0.00 2.45 33 0.00 1.71 0.00 2.04 0.00 2.20 0.00 2.36 0.00 2.41 34 0.00 1.67 0.00 2.00 0.00 2.16 0.00 2.32 0.00 2.38 35 0.00 1.63 0.00 1.97 0.00 2.13 0.00 2.29 0.00 2.35 36 0.00 1.60 0.00 1.94 0.00 2.10 0.00 2.26 0.00 2.32 37 0.00 1.56 0.00 1.91 0.00 2.06 0.00 2.22 0.00 2.28 38 0.00 1.51 0.00 1.87 0.00 2.03 0.00 2.19 0.00 2.25 39 0.00 1.46 0.00 1.84 0.00 2.00 0.00 2.16 0.00 2.22 40 0.00 1.39 0.00 1.81 0.00 1.97 0.00 2.13 0.00 2.18 41 0.00 1.30 0.00 1.77 0.00 1.93 0.00 2.09 0.00 2.15 42 0.00 1.22 0.00 1.74 0.00 1.90 0.00 2.06 0.00 2.12 43 0.00 1.10 0.00 1.70 0.00 1.87 0.00 2.03 0.00 2.08 44 0.00 0.98 0.00 1.66 0.00 1.83 0.00 1.99 0.00 2.05 45 0.00 0.86 0.00 1.63 0.00 1.80 0.00 1.96 0.00 2.02 46 0.00 0.74 0.00 1.59 0.00 1.77 0.00 1.93 0.00 1.99 47 0.00 0.62 0.00 1.55 0.00 1.73 0.00 1.89 0.00 1.95 48 0.00 0.50 0.00 1.50 0.00 1.69 0.00 1.86 0.00 1.92 490.00 0.34 0.00 1.45 0.00 1.66 0.00 1.83 0.00 1.89 'y 50 0.00 0.21 0.00 1.37 0.00 1.62 0.00 1.80 0.00 1.85 51 0.00 0.14 0.00 1.29 0.00 1.58 0.00 1.76 0.00 1.82 52 0.00 0.14 0.00 1.20 0.00 1.54 0.00 1.72 0.00 1.79 53 0.00 0.14 0.00 1.08 0.00 1.49 0.00 1.69 0.00 1.75 54 . 0.00 0.14 0.00 0.96 0.00 1.44 0.00 1.65 0.00 1.72 55 0.00 0.14 0.00 0.84 0.00 1.36 0.00 1.61 0.00 1.68 56 0.00 0.13 0.00 0.72 0.00 1.27 0.00 1.58 0.00 1.64 57 0.00 0.13 0.00 0.60 0.00 1.18 0.00 1.53 0.00 1.61 Inflow Outflow Inflow Outflow Inflow Outflow Inflow Outflow Inflow Outflow 2yr 2yr I0yr IOyr 25yr 25yr 50yr 50yr 100yr 100yr 58 0.00 0.13 0.00 0.48 0.00 1.06 0.00 1.49 0.00 1.57 59 0.00 0.13 0.00 0.31 0.00 0.94 0.00 1.43 0.00 1.52 60 0.00 0.13 0.00 0.19 0.00 0.82 0.00 1.34 0.00 1.48 61 0.00 0.12 0.00 0.14 0.00 0.70 0.00 1.26 0.00 1.41 62 0.00 0.12 0.00 0.14 0.00 0.58 0.00 1.16 0.00 1.32 63 0.00 0.12 0,00 0.14 0.00 0.46 0.00 1.04 0.00 1.24 64 0.00 0.12 0.00 0.14 0.00 0.28 0.00 0.92 0.00 1.13 65 0.00 0.12 0.00 0.14 0.00 0.18 0.00 0.80 0.00 1.01 66 0.00 0.11 0.00 0.13 0.00 0.14 0.00 0.68 0.00 0.89 67 0.00 0.11 0.00 0.13 0.00 0.14 0.00 0.56 0.00 0.77 68 0.00 0.11 0.00 0.13 0.00 0.14 0.00 0.44 0.00 0.65 69 0.00 0.11 0.00 0.13 0.00 0.14 0.00 0.25 0.00 0.53 70 0.00 0.10 0.00 0.13 0.00 0.14 0.00 0.17 0.00 0.40 71 0.00 0.10 0.00 0.12 0.00 0.13 0.00 0.14 0.00 0.23 72 0.00 0.10 0.00 0.12 0.00 0.13 0.00 0.14 0.00 0.16 73 0.00 0.09 0.00 0.12 0.00 0.13 0.00 0.14 0.00 0.14 74 7 0.00 0.08 0.00 0.12 0.00 0.13 0.00 0.14 0.00 0.14 75 0.00 0.08 0.00 0.11 0.00 0.13 0.00 0.14 0.00 0.14 76 0.00 0.07 0.00 0.11 0.00 0.12 0.00 0.13 0.00 0.14 77 0.00 0.07 0.00 0.11 0.00 0.12 0.00 0.13 0.00 0.13 78 0.00 0.07 0.00 0.11 0.00 0.12 0.00 0.13 0.00 0.13 79 0.00 0.06 0.00 0.11 0.00 0.12 0.00 0.13 0.00 0.13 80 0.00 0.06 0.00 0.10 0.00 0.11 0.00 0.13 0.00 0.13 81 0.00 0.05 0.00 0.10 0.00 0.11 0.00 0.12 0.00 0.13 82 ? 0.00 0.05 0.00 0.09 0.00 0.11 0.00 0.12 0.00 0.12 83 0.00 0.05 0.00 0.09 0.00 0.11 0.00 0.12 0.00 0.12 84 . 0.00 0.04 0.00 0.08 0.00 0.11 0.00 0.12 0.00 0.12 85 0.00 0.04 0.00 0.08 0.00 0.10 0.00 0.11 0.00 0.12 86 0.00 0.04 0.00 0.07 0.00 0.10 0.00 0.11 0.00 0.12 87 0.00 0.04 0.00 0.07 0.00 0.09 0.00 0.11 0.00 0.11 88 0.00 0.03 0.00 0.06 0.00 0.09 0.00 0.11 0.00 0.11 89 ,,;; 0.00 0.02 0.00 0.06 0.00 0.08 0.00 0.11 0.00 0.11 90 4 0.00 0.01 0.00 0.06 0.00 0.08 0.00 0.10 0.00 0.11 91 0.00 0.01 0.00 0.05 0.00 0.07 0.00 0.10 0.00 0.10 92 0.00 0.01 0.00 0.05 0.00 0.07 0.00 0.09 0.00 0.10 93 Z4 0.00 0.00 0.00 0.05 0.00 0.06 0.00 0.09 0.00 0.10 _ 94 " 0.00 0.00 0.00 0.04 0.00 0.06 0.00 0.08 0.00 0.09 95 k 0.00 0.00 0.00 0.04 0.00 0.06 0.00 0.08 0.00 0.09 96 0.00 0.00 0.00 0.04 0.00 0.05 0.00 0.07 0.00 0.08 97 0.00 0.00 0.00 0.04 0.00 0.05 0.00 0.07 0.00 0.08 98 0.00 0.00 0.00 0.03 0.00 0.05 0.00 0.06 0.00 0.07 99 0.00 0.00 0.00 0.02 0.00 0.04 0.00 0.06 0.00 0.07 100 0.00 0.00 0.00 0.01 0.00 0.04 0.00 0.06 0.00 0.06 101 0.00 0.00 0.00 0.01 0.00 0.04 0.00 0.05 0.00 0.06 102 Baa 0.00 0.00 0.00 0.00 0.00 0.04 0.00 0.05 0.00 0.05 103 0.00 0.00 0.00 0.00 0.00 0.03 0.00 0.05 0.00 0.05 104 0.00 0.00 0.00 0.00 0.00 0.02 0.00 0.04 0.00 0.05 105 0.00 0.00 0.00 0.00 0.00 0.01 0.00 0.04 0.00 0.05 106 0.00 0.00 0.00 0.00 0.00 0.01 0.00 0.04 0.00 0.04 107 '' 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.04 0.00 0.04 108 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.02 0.00 0.04 109 ' 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.01 0.00 0.03 110 °'`< 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.01 0.00 0.02 111 '' 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.01 0.00 0.01 112 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.01 113 .;; 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.01 114 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 115 10.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 116- v1 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 r- ti L � T N N 3 a O � O u v (0 ro LL. 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L 1 0 - i. 1a 0 +.0U me o^ 7 C o. 0 0. a a, v o i= co Is CO L I / to m c.i I N • • _ O • +u I I II 0 O 0 0 0 O O O 00 lD V N O (sp)a2aeLpsIa L ‘5-.T O O O r( 0 O C O T T U U CO CO u_ LL O '-1 O O '-I r H 0. 1 co '. 0 >, o = 00 0 I kj0 k / N off 3 a, 0 a a 0 ca / - `° c co oE LL L } / O 1 0 'I m N O N cn 00 W O • 111 / 1111 1111 1111 111 O 0 O 0 0 0 O 00 tD [t N O '-1 (sp)a8JeLps!a Pre-Development VS.Post Development Hydrographs Appendix C Pre Post Pre Post Pre Post Pre Post Pre Post 2yr 2yr 1 yr 10yr 25yr 25yr 50yr 50yr 100yr 100yr Time(min) Q(cfs) Q(cfs) Q(cfs) Q(cfs) Q(cfs) Q(cfs) Q(cfs) Q(cfs) Q(cfs) Q(cfs)" 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 1 0.20 0.14 0.28 0.19 0.32 0.21 0.36 0.23 0.38 0.24 2 0.40 0.29 0.56 0.38 0.64 0.42 0.73 0.46 0.76 0.48 3 0.61 0.42 0.84 0.54 0.96 0.61 1.09 0.67 1.13 0.74 4 0.81 0.54 1.12 1.10 1.28 1.31 1.45 1.51 1.51 1.57 5 1.01 1.17 1.40 1.60 1.60 1.82 1.81 2.04 1.89 2.11 6 1.21 1.55 1.68 2.03 1.92 2.24 2.18 2.45 2.27 2.53 7 1.41 1.88 1.96 2.36 2.24 2.58 2.54 2.79 2.65 2.86 8 1.61 2.15 2.24 2.63 2.56 2.85 2.90 3.07 3.03 3.16 9 1.82 2.38 2.52 2.87 2.88 3.11 3.26 3.37 3.40 3.46 10 2.02 2.58 2.80 3.10 3.20 3.38 3.63 3.66 3.78 3.76 11 2.22 2.60 3.08 3.12 3.52 3.40 3.99 3.68 4.16 3.78 12 2.42 2.61 3.36 - 3.84 3.4Qti 4.35 368 ` 4.54 3.79( 13 2.62 2.61 3.63 3.13 4.16 3.40 4.71 3.68 4.92 3.78 14 2.83 2.60 3.91 3.12 4.48 3.38 5.08 3.66 5.30 3.76 15 3.03 2.59 4.19 3.10 4.s0 .. 3.36 5.44 3.63 5.61,% 3.74 16 2.93 2.57 4.05 3.07 4.64 3.33 5.26 3.60 5.48 3.70 17 2.83 2.54 3.91 3.04 4.48 3.29 5.08 3.56 5.30 3.66 18 2.72 2.51 3.77 3.00 4.32 3.25 4.89 3.51 5.11 3.60 19 2.62 2.48 3.63 2.96 4.16 3.20 4.71 3.45 4.92 3.55 20 2.52 2.44 3.50 2.91 4.00 3.15 4.53 3.39 4.73 3.48 21 2.42 2.39 3.36 2.85 3.84 3.08 4.35 3.32 4.54 3.41 22 2.32 2.34 3.22 2.79 3.68 3.02 4.17 3.25 4.35 3.33 23 2.22 2.29 3.08 2.73 3.52 2.95 3.99 3.17 4.16 3.25 24 2.12 2.24 2.94 2.66 3.36 2.87 3.81 3.08 3.97 3.16 25 2.02 2.17 2.80 2.58 3.20 2.79 3.63 2.99 3.78 3.07 26 1.92 2.11 2.66 2.50 3.04 2.70 3.44 2.89 3.59 2.97 27 i 1.82 2.04 2.52 2.42 2.88 2.60 3.26 2.79 3.40 2.86 28 e, 1.72 1.97 2.38 2.33 2.72 2.51 3.08 2.69 3.22 2.75 29 4 1.61 1.89 2.24 2.23 2.56 2.40 2.90 2.57 3.03 2.64 30 1.51 1.81 2.10 2.14 2.40 2.30 2.72 2.45 2.84 2.51 31 1.41 1.78 1.96 2.10 2.24 2.26 2.54 2.42 2.65 2.48 32 1.31 1.74 1.82 2.07 2.08 2.23 2.36 2.39 2.46 2.45 33 1.21 1.71 1.68 2.04 1.92 2.20 2.18 2.36 2.27 2.41 34 1.11 1.67 1.54 2.00 1.76 2.16 1.99 2.32 2.08 2.38 35 ! 1.01 1.63 1.40 1.97 1.60 2.13 1.81 2.29 1.89 2.35 36 ' 0.91 1.60 1.26 1.94 1.44 2.10 1.63 2.26 1.70 2.32 37 0.81 1.56 1.12 1.91 1.28 2.06 1.45 2.22 1.51 2.28 38 i 0.71 1.51 0.98 1.87 1.12 2.03 1.27 2.19 1.32 2.25 39 0.61 1.46 0.84 1.84 0.96 2.00 1.09 2.16 1.13 2.22 40 0.50 1.39 0.70 1.81 0.80 1.97 0.91 2.13 0.95 2.18 41 0.40 1.30 0.56 1.77 0.64 1.93 0.73 2.09 0.76 2.15 42 3 0.30 1.22 0.42 1.74 0.48 1.90 0.54 2.06 0.57 2.12 43 0.20 1.10 0.28 1.70 0.32 1.87 0.36 2.03 0.38 2.08 44 0.10 0.98 0.14 1.66 0.16 1.83 0.18 1.99 0.19 2.05 45 0.00 0.86 0.00 1.63 0.00 1.80 0.00 1.96 0.00 2.02 46 0.00 0.74 0.00 1.59 _ 0.00 1.77 0.00 1.93 0.00 1.99 47 0.00 0.62 0.00 1.55 0.00 1.73 0.00 1.89 0.00 1.95 48 0.00 0.50 0.00 1.50 0.00 1.69 0.00 1.86 0.00 1.92 49 0.00 0.34 0.00 1.45 0.00 1.66 0.00 1.83 0.00 1.89 50 0.00 0.21 0.00 1.37 0.00 1.62 0.00 1.80 0.00 1.85 51 0.00 0.14 0.00 1.29 0.00 1.58 0.00 1.76 0.00 1.82 52 0.00 0.14 0.00 1.20 0.00 1.54 0.00 1.72 0.00 1.79 53 0.00 0.14 0.00 1.08 0.00 1.49 0.00 1.69 0.00 1.75 54 0.00 0.14 0.00 0.96 0.00 1.44 0.00 1.65 0.00 1.72 55 0.00 0.14 0.00 0.84 0.00 1.36 0.00 1.61 0.00 1.68 56 0.00 0.13 0.00 0.72 0.00 1.27 0.00 1.58 0.00 1.64 57 0.00 0.13 0.00 0.60 0.00 1.18 0.00 1.53 0.00 1.61 L I r Pre Post Pre Post Pre Post Pre Post Pre Post 2yr 2yr l0yr l0yr 25yr 25yr 50yr 50yr 100yr 100yr 58 0.00 0.13 0.00 0.48 0.00 1.06 0.00 1.49 0.00 1.57 59 0.00 0.13 0.00 0.31 0.00 0.94 0.00 1.43 0.00 1.52 60 0.00 0.13 0.00 0.19 0.00 0.82 0.00 1.34 0.00 1.48 61 0.00 0.12 0.00 0.14 0.00 0.70 0.00 1.26 0.00 1.41 62 0.00 0.12 0.00 0.14 0.00 0.58 0.00 1.16 0.00 1.32 63 0.00 0.12 0.00 0.14 0.00 0.46 0.00 1.04 0.00 1.24 64 0.00 0.12 0.00 0.14 0.00 0.28 0.00 0.92 0.00 1.13 65 0.00 0.12 0.00 0.14 0.00 0.18 0.00 0.80 0.00 1.01 66 0.00 0.11 0.00 0.13 0.00 0.14 0.00 0.68 0.00 0.89 67 0.00 0.11 0.00 0.13 0.00 0.14 0.00 0.56 0.00 0.77 68 0.00 0.11 0.00 0.13 0.00 0.14 0.00 0.44 0.00 0.65 69 0.00 0.11 0.00 0.13 0.00 0.14 0.00 0.25 0.00 0.53 70 0.00 0.10 0.00 0.13 0.00 0.14 0.00 0.17 0.00 0.40 71 0.00 0.10 0.00 0.12 0.00 0.13 0.00 0.14 0.00 0.23 72 0.00 0.10 0.00 0.12 0.00 0.13 0.00 0.14 0.00 0.16 73 0.00 0.09 0.00 0.12 0.00 0.13 0.00 0.14 0.00 0.14 74 0.00 0.08 0.00 0.12 0.00 0.13 0.00 0.14 0.00 0.14 75 0.00 0.08 0.00 0.11 0.00 0.13 0.00 0.14 0.00 0.14 76 0.00 0.07 0.00 0.11 0.00 0.12 0.00 0.13 0.00 0.14 77 0.00 0.07 0.00 0.11 0.00 0.12 0.00 0.13 0.00 0.13 78 r 0.00 0.07 0.00 0.11 0.00 0.12 0.00 0.13 0.00 0.13 79 0.00 0.06 0.00 0.11 0.00 0.12 0.00 0.13 0.00 0.13 80 0.00 0.06 0.00 0.10 0.00 0.11 0.00 0.13 0.00 0.13 81 0.00 0.05 0.00 0.10 0.00 0.11 0.00 0.12 0.00 0.13 82 0.00 0.05 0.00 0.09 0.00 0.11 0.00 0.12 0.00 0.12 83 0.00 0.05 0.00 0.09 0.00 0.11 0.00 0.12 0.00 0.12 84 0.00 0.04 0.00 0.08 0.00 0.11 0.00 0.12 0.00 0.12 85 0.00 0.04 0.00 0.08 0.00 0.10 0.00 0.11 0.00 0.12 86 0.00 0.04 0.00 0.07 0.00 0.10 0.00 0.11 0.00 0.12 87 0.00 0.04 0.00 0.07 0.00 0.09 0.00 0.11 0.00 0.11 88 r 0.00 0.03 0.00 0.06 0.00 0.09 0.00 0.11 0.00 0.11 89 0.00 0.02 0.00 0.06 0.00 0.08 0.00 0.11 0.00 0.11 90 0.00 0.01 0.00 0.06 0.00 0.08 0.00 0.10 0.00 0.11 91 0.00 0.01 0.00 0.05 0.00 0.07 0.00 0.10 0.00 0.10 92 0.00 0.01 0.00 0.05 0.00 0.07 0.00 0.09 0.00 0.10 93 0.00 0.00 0.00 0.05 0.00 0.06 0.00 0.09 0.00 0.10 94 0.00 0.00 0.00 0.04 0.00 0.06 0.00 0.08 0.00 0.09 95 0.00 0.00 0.00 0.04 0.00 0.06 0.00 0.08 0.00 0.09 96 0.00 0.00 0.00 0.04 0.00 0.05 0.00 0.07 0.00 0.08 97 0.00 0.00 0.00 0.04 0.00 0.05 0.00 0.07 0.00 0.08 98 0.00 0.00 0.00 0.03 0.00 0.05 0.00 0.06 0.00 0.07 99 0.00 0.00 0.00 0.02 0.00 0.04 0.00 0.06 0.00 0.07 100 0.00 0.00 0.00 0.01 0.00 0.04 0.00 0.06 0.00 0.06 101 0.00 0.00 0.00 0.01 0.00 0.04 0.00 0.05 0.00 0.06 102 0.00 0.00 0.00 0.00 0.00 0.04 0.00 0.05 0.00 0.05 103 0.00 0.00 0.00 0.00 0.00 0.03 0.00 0.05 0.00 0.05 104 0.00 0.00 0.00 0.00 0.00 0.02 0.00 0.04 0.00 0.05 105 0.00 0.00 0.00 0.00 0.00 0.01 0.00 0.04 0.00 0.05 106 0.00 0.00 0.00 0.00 0.00 0.01 0.00 0.04 0.00 0.04 107 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.04 0.00 0.04 108 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.02 0.00 0.04 109 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.01 0.00 0.03 110 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.01 0.00 0.02 111 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.01 0.00 0.01 112 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.01 113 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.01 114 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 115 ` -`,'° 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 116 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 N• N C• CU 0. 0 O O 41 > a)aJ 0 CL a I I I0 0 - Q1 L a. 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E ai i r £ ii r = o Ls) Lfl cn O O O O O Lei N o (sp)a2JegDsia CL\ Drainage Report for SECOND STREET APARTMENTS COLLEGE STATION, TEXAS January 2015 Owner: CS Second Street Apartments II, LLC 16800 Westgrove Drive, Suite 600 Addison, Texas 75001 Developer: Seneca Investments 16800 Westgrove Drive, Suite 100 Addison, Texas 75001 Prepared By: Schultz Engineering, LLC TBPE Firm No. 12327 P.O. Box 11995 College Station, TX 77842* ' "" ( " loc)-`1(dotO 2730 Longmire Drive, Suite 1�E ? ` \re, S�Otnlc� College Station, Texas 7784 (o`, _c e0,0evrck oe+fie (979) 764-3900 44(Q- CkoorA oleAs g, 414)2 *ApAN-5i5 s- i Drainage Report—Executive Summary Second Street Apartments College Station,Texas ENGINEER Schultz Engineering,LLC P.O.Box 11995 College Station,Texas 77842 Phone: (979)764—3900 OWNER CS Second Street Apartments II,LLC 16800 Westgrove Drive,Suite 600 Addison,Texas 75001 DEVELOPER Seneca Investments 16800 Westgrove Drive,Suite 100 Addison,Texas 75001 Phone: (214)265-8686 GENERAL DESCRIPTION AND LOCATION This project consists of the redevelopment of Lots 1-8,Block 20 of the W.C.Boyett Estate Partition in College Station,Texas. This NG-3 zoned site project will include the construction of a multi-family building,parking garage,sitework,utilities and other infrastructure. This project is at the corner of Second Street and Cherry Street,as well as,the corner of Cherry Street and Boyett Street. Site Area:0.901 Existing Land Use:NG-3 Proposed Land Use:NG-3 Number of Lots: 8 Drainage Basin:Burton Creek Watershed FEMA FIRM: #48041C0305F,Dated April 2,2014 Floodplain:None of the development lies within the floodplain. HYDROLOGIC CHARACTERISTICS The pre-development condition of the land was developed with single family and duplex housing and driveways.Exhibit A shows the pre-development and post development drainage areas and the runoff flow direction.The existing flow patterns show that a majority of the property drains southwest toward the Cherry Street/Boyett Street corner,eventually entering the right-of-way being conveyed as surface flow down Boyett Street to a tributary of Burton Creek. GENERAL STORMWATER PLAN The drainage plan for this development will involve the installation of an onsite underground detention facility. The vault will be located under the first level parking garage on the Boyett Street side of the Page 1 of 5 Drainage Report—Executive Summary Second Street Apartments College Station,Texas project. The storm water runoff from roof,building and parking garages will be collected and conveyed through the detention facility. The detention facility will have outfall structure on the outside of the structure and discharge into a proposed storm sewer system to be installed in Boyett Street to the Burton Creek Tributary outfall. The proposed detention facility will capture the proposed storm runoff and discharge at a rate equal to or less than the existing design flows. A small portion of the area from the building to the back of curb will bypass the detention facility and discharge directly into the surrounding streets similar to existing flow patterns. The combination of area bypassing the detention facility and the detention facility outflow will be less than or equal to the pre-developed condition for the site. Exhibit B shows the post-development topography and the runoff flow direction. COORDINATION& STORMWATER PERMITTING The project will not require a permit to be prepared to comply with the Texas Commission for Environmental Quality storm water permitting for the construction site,because the site is less than 1 acre. No other permits are anticipated for this project. DRAINAGE DESIGN General Information: Stormwater runoff from the development will be collected and routed through the detention facility and then discharged into the proposed storm sewer system to be installed in Boyett Street.A portion of the lot,the area between the building and back of curb will bypass the detention facility and discharge directly into the surrounding streets similar to existing flow patterns. The combination of area bypassing the detention facility and the detention facility outflow will be less than or equal to the pre-developed condition for the site. The runoff enters the detention facility from a series of storm sewer pipes. Detention Facility Analysis TT Methodology: TR 55 T,Minimum: 10 minutes Design Storm Events: 2-year, 10-year,25-year,50-year and 100-year detention facility 10-year design& 100-year analysis for public storm sewer system Pond Discharge Pipe &Public Storm Sewer Materials: Class III RCP,Profile Gasket in accordance with ASTM C443,ASTM C76 Manning's n Value: 0.013 Runoff Coefficients: 0.55 for existing conditions,0.92 for developed conditions contributing to detention facility&0.72 for developed conditions contributing directly offsite. Design Constraints: Max.water depth in the parking lot=6 in.or 0.5 ft.for 100 year storm event. Min.flow velocity=2.5 fps Max.flow velocity= 15 fps Post-Development peak runoff less than or equal to existing storm water runoff from the site. Page 2 of 5 Drainage Report—Executive Summary Second Street Apartments College Station,Texas Rational Equation: The rational equation is utilized to determine peak storm water runoff rates for the Detention Facility design. Q=CIA Q=Flow(cfs) A=Area(acres) C=Runoff Coefficient I=Rainfall Intensity(in/hr) Design Software: Excel spreadsheets,AutoCAD Hydraflow Express,AutoCAD Hydraflow Hydrographs Extension The software was used to compute the pond storage and discharge data and the pre and post-development peak runoffs and the routing of the flow through the detention facility. The requirement for a 25%reduction in cross sectional area of pipes 24"in diameter or less is achieved by using internal pipe diameters that are less than the standard diameter. The 18"diameter pipe areas were reduced by 25%and a 15.6"diameter pipe was used in the analysis. Design Results: The data presented in the Appendices and in the following tables indicates the detention facility sizing and discharges are in accordance with the requirements of the design guidelines. Refer to Appendix B for design calculations for the storm sewer pipes. Applicable Exhibits: Exhibit A—Pre-development Drainage Area Map Exhibit B—Post-development Drainage Area Map Appendix A—Drainage Area Summary—Detention Facility Appendix B—Pipe Design Summary Appendix C—Detention Facility Data and Hydrographs Design Analysis: The post-development drainage areas are shown on Exhibit B. The design data and descriptions of the detention facility outlet structures,discharge pipes and overflow spillways are found in Appendix C. A portion of site between the building and back of curb will bypass the detention facility and discharge directly into the surrounding streets similar to existing flow patterns. The combination of area bypassing the detention facility and the detention facility outflow will be less than or equal to the pre-developed condition. Sedimentation in the detention facility is not likely due to the small drainage areas that are mostly paved areas and the use of underground detention in storm sewer pipes.However,the design storage capacity of the detention facility was increased by 10%in the event that sediment does build up. The peak flow out of the detention facility was determined by a Storage Routing Analysis based on the Continuity Equation as follows: (I1+I2)+((2s1/dt)- 01)=((2s2/dt)=O2). The time interval,dt,used was 1 minute. The calculations and results of the Storage Routing Analysis were used to generate hydrograph peak flows and graphs for the pre and post development conditions. A summary of the pre and post development runoff information from the site is shown in Table 2. Page 3 of 5 Drainage Report-Executive Summary Second Street Apartments College Station,Texas The flow out of the detention facility is controlled by an 8"x 8"orifice and a 3' wide rectangular weir located in the detention facility outlet structure. The rim of the outlet structure is 343.94'. The detention facility discharges into a proposed storm sewer system to be installed in Boyett Street. TABLE 1-Pre-&Post-Development Runoff Input Information Tc Area# Area (Acres) C (Min.) Pre 101 1.05 0.55 15 Post 201 0.83 0.92 10 Post 202 0.22 0.72 10 TABLE 2-Pre-&Post-Development Runoff Comparison-Detention Analysis Q2 Q10 Q25 Q50 Q100 Location cfs cfs cfs cfs cfs Pre-Development 3.00 4.15 4.76 5.39 5.62 (Area 101) Post Development with Detention Post-Development 4.83 6.59 7.53 8.51 8.89 (Area 201) Post-Development 1.00 1.37 1.56 1.77 1.84 (Area 202) Detention Facility Outfall 2.19 2.57 2.78 2.95 3.16 (Area 201 Routed Through Facility) Combined Outflow 2.85 3.42 3.72 4.03 4.14 (Compare to Area 101) Decrease in Peak Flow 0.15 0.73 1.04 1.36 1.48 As shown in Table 2,the post-development peak outflow from the project site is less than the allowable peak outflow for each design storm event. Additionally, Tables 3 presents the maximum water surface and the amount of freeboard for the Detention Facility. The peak flow out of the detention facility and the maximum water surface was determined by the Storage Routing Analysis. Page 4 of 5 Drainage Report—1xecutive Summary Second Street Apartments College Station,Texas The proposed 18"diameter storm sewer pipe to be constructed in Boyett Street has a capacity greater than the maximum detention facility discharge rate of 3.16 cfs,as shown in Appendix B. TABLE 3—Summary of Detention Facility Maximum Water Surface Levels Storm Event Peak Flow out of Water Surface Freeboard Facility,(cfs) Elevation,ft. ft. 2-year 2.19 341.53 2.47 10-year 2.57 342.17 1.83 25-year 2.78 342.53 1.47 50-year 2.95 342.91 1.09 100-year 3.16 343.05 0.95 The 100 year water surface is below the rim elevation of the outfall structure. If the pond outlet orifice clogs,the water will discharge through the 3' wide rectangular weir. CONCLUSION The onsite detention facility for the development will function within the requirements and restrictions of the BCS Drainage Design Guidelines. CERTIFICATION "This report for the drainage design of the Second Street Apartments was prepared by me in accordance with the provisions of the Bryan/College Station Unified Drainage Design Guidelines for the owners of the property. All licenses and permits required by any and all state and federal regulatory agencies for the proposed drainage improvements have been issued." sl� ' �. : Deven L.Doyen,P.E. 1 *.�. it '.* ♦ DEVEN L. DOYEN ill 109835+ . , •4,04,10 ‘15116 FIRM # 12327 Page 5 of 5 SCHULT2 ENGINEERING, LLC EXHIBIT A Pre-Development Drainage Area Map ° ^ 40 0 20 SCALE IN FEET L \ � \ . ` / \ ` . / \ \ / . . / \ ' / / ' \ / ` \ / / \ �-��~~� ~~ 42~~ )1 - -' \ T \ \ ^^ \ \ | / \ SCALE EXHIBIT EXHIBIT B Post-Development Drainage Area Map J ,, • • STANDARD STOR INLET RING: COVER NM - 20 3'ME wE:ll- y /'i/.._ ' 343.94' SCALE IN FEET '` 0•45' 1.THICK CONCRETE F ''' /P , . 343.00' ---�NRN 8'x8.ORIFICE �ai � ►i�i��iiiiit � r viii♦iiil 1e. .,. �iiiiiiiiiiii 35 STORM SERER i 4...i�iiii 1 ..4. ..CIFi a . 339.50' ! ! I +t SECTION 8-6 4•TREE%ELL STORMDRAIN PIPEI 4' I 8•RCP STORM SEWER 111. . IL, I 1 :TANDARD STOR L 1 -ET RING: COVER I 'TREE WELL p STORM DRAIN W PIPE 1 ,'I T\\'IP\\ 1 STANDARD STOP R II INLET RING: COVE �y I 11 al / <CONCRETE� i/� i ' . 343.94' / x8.OPoFlCE . 343.00' I \ /el ilk I / R 1.25' ..S' 8 RCP I _ STORM SERER mmimiiii II TREE MhLL / // // \ SECTION A-A DRAIN 339.50' v' UNDERGROUND DETENTION VAl'I'I' r"1 / OUTLET STRUCrI RL DL:'I.AII. OUTFALL / HEADWALL% i PIPE 100 ,'. i 18" RCP b, ` e '' o _-........ 0 0.409; SLOPE N. ST — ST — ST — ST ---..-§T -K_I PROPOSED ,4 JUNCTION 80X -- • I _ —341 u ---342 - 1 _ __ _ Y 1 1 Schultz En, SCALE EXHIBIT ' __ �LOPMENT _ DESNNDLD 979.7E /J-�'7/jy� HAP {]J� © © N STRONGD EoAl YL1� /�/,/�/ .NOIPII0111/u= APPENDIX A Drainage Area Summary—Detention Facility N P V — C a .fir V1 xi M 7 L. O L R oT p L M V O se .. _ ›. O F M V1 N O'. O N 6 a 00 .. �i .4 .a 1-1i o moo` II II II ° o .X ... > , a o0 0 - $_ H II .n 'C N O T.:. M r "' O .g a M • O N ,0 M \O! 00 N ^C V 7 1--. N t•-; C V1 O o n y oo CO C II II II T .;'-` ..0 b 7) O N .r.. t N 000 0g0 h •zi00 O, O N I-- N VV M n R kn 8 a 7 '�O N ri .. 7 y`O. O h l� 00 00 0 :a C II II II T s:' D b N O b s N ., C r- 06 06 C M O c V O 00 O 00 6 M 7 ••; N ,-,i fi M d 0 o O n _ ., 00 00 0 ` tt II II II _ ? .n b N N O' m M 111O = M M r C 00 •.. C 0 .0 O bJ A .0c 0. o oo 0a o C ra C .0 4 E , °. y -d o o °y 00 0` - 9R x w 3 0 + OO a O N y C A 'IIC I)I at p ON N O` O O O C . Hd • omIC3 �.C 0aQ 2 0) 2toh _C > L a OYC R d omE5 E N0 tl LE ,ti. o cj 47 o z C Y N O y ca w b 7 a°) U L L 0 O O L A - � 0 b 74 4W rI'j U .C. O 1111 1 O O O D ^ huh,.,, N N '� E 5; O o 0 R a y L U II I I I 11 v� QaA ,f:,41E.. aa ¢ U APPENDIX B Pipe Design Summary L S cco co co co 0 0 co co a (.00 co co co.2 M M M M N O CD ,_ c0 F., r u' 0 M M M M O co O O r.- 6 N N- N O O O O o.. co to co co . M M M M N. N- N- d V co to to co N N N (Ni CO C 3H M N °'Q„ 0 0 0 CO ,— r E X 0 0 U Z To Tri a = d Q a c y 0 00 0 0 00 c 0 0 00 U a_ d d a. co C '�_. O co O O N L P") co d $ M N CO J N coNN_ N C CO CO CO CO y �.• r r r ‘- O.a 'a N a+ II 30 p co N r O O Z O O O co � a a o . 0 a APPENDIX C Detention Facility Data & Hydrographs Detention Facility Appendix C Detention Facility Summary Detention Facility Design Storm Inflow Outflow W.S.Elevation (yr) (cfs) (cfs) (ft) 2 4.83 2.19 341.53 10 6.59 2.57 342.17 25 7.53 2.78 342.53 50 8.51 2.95 342.91 100 8.89 3.16 343.05 *Top of outfall structure=343.94',Weir Crest Elevation= 343.00' Detention Facility Appendix C Detention Facility Area-Capacity Data Detention Facility Storage 90% Elevation Depth Volume Cumulative Cumulative Volume Volume (ft) (ft) (ft3) (ft3) (ft3) 339.50 0.00 0 0 0 340.0 0.50 77 77.33 70 341.0 1.50 1,083 1160.5 1,055 342.0 2.50 1,856 3016.2 2,742 343.0 3.50 1,856 4871.9 4,429 344.0 4.50 1,857 6728.7 6,117 Detention Facility Appendix C Elevation-Discharge Data Depth-Discharge Data 8" x 8" 3' Rectangular Facility Orifice Weir Total Design Elevation Depth Flow Spillway Flow (ft) (ft) (cfs) (cfs) (cfs) 339.5 0.0 0.00 0.00 0.00 340.0 0.5 0.33 0.00 0.33 341.0 1.5 1.82 0.00 1.82 342.0 2.5 2.47 0.00 2.47 343.0 3.5 2.99 0.00 2.99 344.0 4.5 3.43 9.99 13.42 Notes: 1. The Outlet Structure is a junction box with a 8" x 8" Orifice and a 3'Wide Rectangular Weir 2. The rectangular spillway will serve as the overflow spillway. Detention Facility Plugged Condition The 100 year water surface is below the rim elevations of the outlet structure. If the facility outlet orifice clogs,the water will discharge through the 3'wide rectangular weir. Detention Facility Appendix C Storage Routing Analysis Parameters t=60s Detention Facility Elevation Depth Discharge Storage 2 s/t 2 s/t+0 (ft) (ft) (0, cfs) (s, cf) 339.50 0.0 0.00 0.0 0.0 0.00 340.00 0.5 0.33 70.3 2.3 2.67 341.00 1.5 1.82 1055.0 35.2 36.98 342.00 2.5 2.47 2742.0 91.4 93.87 343.00 3.5 2.99 4429.0 147.6 150.62 344.00 4.5 13.42 6117.0 203.9 217.32 *The flow control structure for the smaller storms is an 8"x8" orifice and a 3'wide rectangular weir. i Detention Facility Inflow&Outflow Hydrographs Appendix C Inflow Outflow Inflow Outflow Inflow Outflow Inflow Outflow Inflow Outflow 2yr 2yr 10yr 10yr 25yr 25yr 50yr 50yr IOOyr IOOyr Time(min) Q(cfs) Q(cfs) Q(cfs) Q(cfs) Q(cfs) Q(cfs) Q(cfs) Q(cfs) Q(cfs) Q(cfs) 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0,00 0.00 0.00 1 0.48 0.03 0.66 0.05 0.75 0.06 0.85 0.07 0.89 0.07 2 0.97 0.22 1.32 0.31 1.51 0.33 1.70 0.34 1.78 0.34 3 1.45 0.35 1.98 0.37 2.26 0.39 2.55 0.42 2.67 0.44 4 1.93 0.41 2.64 0.52 3.01 0.62 3.40 0.73 3.56 0.78 5 2.42 0.58 3.30 0.88 3.77 1.00 4.26 1.11 4.44 1.15 6 2.90 0.89 3.96 1.17 4.52 1.30 5.11 1.42 5.33 1.47 7 3.38 1.14 4.62 1.44 5.27 1.58 5.96 1.72 6.22 1.76 8 3.86 1.36 5.27 1.69 6.02 1.82 6.81 1.89 7.11 1.92 9 4.35 1.57 5.93 1.86 6.78 1.94 7.66 2.03 8.00 2.06 10 4.83 1.77 6.59 1.98 7.53 2.07 8.51 2.17 8.89 2.21 11 4.59 1.87 6.26 2.09 7.15 2.20 8.09 2.31 8.44 2.35 12 4.35 1.94 5.93 2.18 6.78 2.30 7.66 2.42 8.00 2.47 13 4.11 2.00 5.60 2.26 6.40 2.39 7.24 2.53 7.55 2.57 14 3.86 2.04 5.27 2.33 6.02 2.47 6.81 2.61 7.11 2.67 15 3.62 2.09 4.94 2.39 5.65 2.54 6.38 2.69 6.67 2.74 16 3.38 2.12 4.62 2.44 5.27 2.59 5.96 2.75 6.22 2.81 17 3.14 2.15 4.29 2.48 4.89 2.64 5.53 2.80 5.78 2.87 18 2.90 2.17 3.96 2.51 4.52 2.68 5.11 2.85 5.33 2.91 19 2.66 2.18 3.63 2.53 4.14 2.71 4.68 2.88 4.89 2.95 20 2.42 2.19 3.30 2.55 3.77 2.73 4.26 2.91 4.44 2.98 21 2.17 2.19 2.97 2.56 3.39 2.75 3.83 2.93 4.00 3.05 22 1.93 2.19 2.64 `2.57 3.01 2.76 3.40 2.94 3.56 3.14 23 1.69 2.18 2.31 2.57 2.64 2.76 2.98 2.95 3.11 3.16 24 1.45 2.16 1.98 2.56 2.26 2.75 2.55 2.94 2.67 3.13 25 1.21 2.15 1.65 2.54 1.88 2.74 2.13 2.93 2.22 3.05 26 0.97 2.12 1.32 2.52 1.51 2.72 1.70 2.92 1.78 2.98 27 0.72 2.09 0.99 2.50 1.13 2.69 1.28 2.89 1.33 2.96 28 0.48 2.06 0.66 2.46 0.75 2.66 0.85 2.86 0.89 2.93 29 0.24 2.01 0.33 2.42 0.38 2.62 0.43 2.82 0.44 2.89 30 0.00 1.97 0.00 2.38 0.00 2.58 0.00 2.77 0.00 2.84 31 0.00 1.92 0.00 2.33 0.00 2.53 0.00 2.72 0.00 2.79 32 0.00 1.87 0.00 2.28 0.00 2.48 0.00 2.67 0.00 2.74 33 0.00 1.82 0.00 2.23 0.00 2.43 0.00 2.62 0.00 2.69 34 0.00 1.72 0.00 2.18 0.00 2.38 0.00 2.57 0.00 2.64 35 0.00 1.60 0.00 2.12 0.00 2.32 0.00 2.52 0.00 2.59 36 0.00 1.48 0.00 2.07 0.00 2.27 0.00 2.47 0.00 2.54 37 0.00 1.37 0.00 2.02 0.00 2.22 0.00 2.42 0.00 2.49 38 0.00 1.25 0.00 1.97 0.00 2.17 0.00 2.37 0.00 2.44 39 0.00 1.13 0.00 1.92 0.00 2.12 0.00 2.32 0.00 2.39 40 0.00 1.02 0.00 1.87 0.00 2.07 0.00 2.27 0.00 2.34 41 0.00 0.89 0.00 1.82 0.00 2.02 0.00 2.22 0.00 2.29 42 0.00 0.78 0.00 1.73 0.00 1.97 0.00 2.17 0.00 2.24 43 0.00 0.65 0.00 1.62 0.00 1.92 0.00 2.12 0.00 2.19 44 0.00 0.55 0.00 1.50 0.00 1.87 0.00 2.07 0.00 2.14 45 0.00 0.50 0.00 1.38 0.00 1.82 0.00 2.02 0.00 2.09 46 0.00 0.45 0.00 1.27 0.00 1.73 0.00 1.97 0.00 2.04 47 0.00 0.41 0.00 1.15 0.00 1.62 0.00 1.92 0.00 1.99 48 0.00 0.38 0.00 1.03 0.00 1.50 0.00 1.87 0.00 1.94 49 0.00 0.37 0.00 0.91 0.00 1.38 0.00 1.82 0.00 1.89 50 0.00 0.36 0.00 0.80 0.00 1.26 0.00 1.73 0.00 1.84 51 0.00 0.35 0.00 0.67 0.00 1.15 0.00 1.61 0.00 1.76 52 0.00 0.33 0.00 0.56 0.00 1.03 0.00 1.49 0.00 1.65 53 0.00 0.27 0.00 0.50 0.00 0.91 0.00 1.38 0.00 1.53 54 0.00 0.19 0.00 0.46 0.00 0.80 0.00 1.26 0.00 1.41 55 0.00 0.13 0.00 0.42 0.00 0.67 0.00 1.14 0.00 1.30 56 0.00 0.10 0.00 0.39 0.00 0.56 0.00 1.03 0.00 1.18 57 0.00 0.07 0.00 0.37 0.00 0.50 0.00 0.91 0.00 1.06 Inflow Outflow Inflow Outflow Inflow Outflow Inflow Outflow Inflow Outflow 2yr 2yr IOyr 10yr 25yr 25yr 50yr 50yr 100yr 100yr 58 0.00 0.05 0.00 0.36 0.00 0.46 0.00 0.79 0.00 0.94 59 0.00 0.04 0.00 0.35 0.00 0.42 0.00 0.66 0.00 0.83 60 0.00 0.03 0.00 0.34 0.00 0.39 0.00 0.56 0.00 0.70 61 0.00 0.03 0.00 0.28 0.00 0.37 0.00 0.50 0.00 0.59 62 0.00 0.02 0.00 0.20 0.00 0.36 0.00 0.46 0.00 0.51 63 0.00 0.02 0.00 0.14 0.00 0.35 0.00 0.42 0.00 0.47 64 0.00 0.02 0.00 0.10 0.00 0.34 0.00 0.39 0.00 0.43 65 0.00 0.01 0.00 0.07 0.00 0.28 0.00 0.37 0.00 0.39 66 0.00 0.01 0.00 0.06 0.00 0.20 0.00 0.36 0.00 0.38 67 0.00 0.01 0.00 0.04 0.00 0.14 0.00 0.35 0.00 0.36 68 0.00 0.01 0.00 0.03 0.00 0.10 0.00 0.33 0.00 0.35 69 0.00 0.01 0.00 0.03 0.00 0.07 0.00 0.28 0.00 0.34 70 0.00 0.01 0.00 0.02 0.00 0.05 0.00 0.19 0.00 0.30 71 0.00 0.01 0.00 0.02 0.00 0.04 0.00 0.14 0.00 0.22 72 0.00 0.01 0.00 0.02 0.00 0.03 0.00 0.10 0.00 0.15 73 0.00 0.01 0.00 0.01 0.00 0.03 0.00 0.07 0.00 0.11 74 0.00 0.01 0.00 0.01 0.00 0.02 0.00 0.05 0.00 0.08 75 0.00 0.00 0.00 0.01 0.00 0.02 0.00 0.04 0.00 0.06 76 0.00 0.00 0.00 0.01 0.00 0.02 0.00 0.03 0.00 0.05 77 0.00 0.00 0.00 0.01 0.00 0.01 0.00 0.03 0.00 0.04 78 0.00 0.00 0.00 0.01 0.00 0.01 0.00 0.02 0.00 0.03 79 0.00 0.00 0.00 0.01 0.00 0.01 0.00 0.02 0.00 0.02 80 0.00 0.00 0.00 0.01 0.00 0.01 0.00 0.02 0.00 0.02 81 0.00 0.00 0.00 0.01 0.00 0.01 0.00 0.01 0.00 0.02 82 0.00 0.00 0.00 0.01 0.00 0.01 0.00 0.01 0.00 0.01 83 0.00 0.00 0.00 0.00 0.00 0.01 0.00 0.01 0.00 0.01 84 0.00 0.00 0.00 0.00 0.00 0.01 0.00 0.01 0.00 0.01 85 0.00 0.00 0.00 0.00 0.00 0.01 0.00 0.01 0.00 0.01 86 0.00 0.00 0.00 0.00 0.00 0.01 0.00 0.01 0.00 0.01 87 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.01 0.00 0.01 88 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.01 0.00 0.01 89 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.01 0.00 0.01 90 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.01 0.00 0.01 91 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.01 92 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 93 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 94 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 95 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 96 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 97 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 98 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 99 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 100 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 101 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 102 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 103 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 104 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 105 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 106 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 107 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 108 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 109 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 110 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 111 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 112 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 113 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 114 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 115 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 116 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 ‘5. T T N N ?� 0 o C T T Y �+ u 'u to CO U- I I O _ C{ i-1 0 --- O '-i 0 01 N a � LhaLo , O - 0 00 L 4-1 �• V r 3 X O --a- • c aC 3 a F 3 o• a d 0 0N do I / 0 rn N O N 144 00 00 _ 0 4414" • 0 0 0 0 tp N O (sp)a2ietpsip '5. O 0 i 0 O 95 C O ? T U U CO (0 U.. LL 1 O '--I -1 0 O '-1 O 01 Q co L O 0 L 00 0 U 3 X Oa C O 0. co co` / CU O ei o / ' O lf1 • • O O O O O pp N O (sp)a2ieLpsia � N N ?� 0 o C O T T 'u U fo Co W LL Ir r 0 0 0 0 N Q) Z a ca 0 L O 0 T 0 0 7 K O •- o2S c 0 a c Q / E ' E / o CO / U, L / CO v ' o N N ` _ O N m 1 n y► o .-1 0 0 0 0 op tD ct N O (sp)a2.ieLpsia � O O U) 0 o w � c O > T i+ Y UU f6 (0 LL LL I 1 0 - '-i 0 O I 11 V) 0 s CL co 0 1 o / 0 r9 x J oif c d o a = a i E E o COW L C o � o cNi rn ` O t!1 00 O 1 � � 1 ` 1 - O O O O O O O O ai t0 (NI O (sp)a2.ieipsia i O O• O O 0 o • O Y Y u u co co U LL 0 .--i 0 H s 0 a O1 ca o L O _ ` CO 3 � 1 +' U / O 3 N 0 x ! w c C 3 a, C a / O a T• Q � / LO CV LL t o 0 0 j l 0 co / m m _ O oorn 00 L 0 0 0 0 0 0 0 oo t; N O (s;p)alieLPS!a i Pre-Development VS.Post Development Hydrographs Appendix C Pre Post Pre Post Pre Post Pre Post Pre Post 2yr 2yr 10yr 10yr 25yr 25yr 50yr 50yr 100yr IOOyr Time(min) Q(cfs) Q(cfs) Q(cfs) Q(cfs) Q(cfs) Q(cfs) Q(cfs) Q(cfs) Q(cfs) Q(cfs) 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 1 0.20 0.13 0.28 0.18 0.32 0.21 0.36 0.25 0.38 0.26 2 0.40 0.42 0.56 0.59 0.64 0.65 0.73 0.69 0.76 0.71 3 0.61 0.65 0.84 0.78 0.96 0.86 1.09 0.95 1.13 0.99 4 0.81 0.81 1.12 1.07 1.28 1.24 1.45 1.44 1.51 1.52 5 1.01 1.09 1.40 1.56 1.60 1.78 1.81 1.99 1.89 2.07 6 1.21 1.49 1.68 2.00 1.92 2.24 2.18 2.48 2.27 2.58 7 1.41 1.84 1.96 2.40 2.24 2.68 2.54 2.96 2.65 3.05 8 1.61 2.16 2.24 2.79 2.56 3.07 2.90 3.31 3.03 3.39 9 1.82 2.47 2.52 3.09 2.88 3.35 3.26 3.62 3.40 3.72 10 2.02 2.77 2.80 3.34 3.20 3.64 3.63 3.94 3.78 4.05 11 2.22 2.82 3.08 3.38 3.52 3.68 3.99 3.99 4.16 4.10 12 2.42 2.84 3.36 3.41 3.84 3.71 4.35 4.01 4.54 4.13 13 2.62 2.85, 3.63 3.42 4.16 3.72 4.71 4.03 4.92 4.14 14 2.83 2.85 3.91 3.42 4.48 3.72 5.08 4.02 5.30 4.14 15 3.03 2.84 4.19 3.41 4.80 3.71 5.44 4.01 5.67 4.13 16 2.93 2.82 4.05 3.39 4.64 3.69 5.26 3.99 5.48 4.10 17 2.83 2.80 3.91 3.37 4.48 3.66 5.08 3.95 5.30 4.06 18 2.72 2.77 3.77 3.33 4.32 3.62 4.89 3.91 5.11 4.02 19 2.62 2.73 3.63 3.29 4.16 3.57 4.71 3.86 4.92 3.96 20 2.52 2.69 3.50 3.24 4.00 3.51 4.53 3.79 4.73 3.90 21 2.42 2.64 3.36 3.18 3.84 3.45 4.35 3.73 4.54 3.88 22 2.32 2.59 3.22 3.12 3.68 3.38 4.17 3.65 4.35 3.87 23 2.22 2.53 3.08 3.05 3.52 3.30 3.99 3.56 4.16 3.81 24 2.12 2.47 2.94 2.97 3.36 3.22 3.81 3.47 3.97 3.68 25 2.02 2.40 2.80 2.89 3.20 3.13 3.63 3.38 3.78 3.51 26 1.92 2.32 2.66 2.80 3.04 3.03 3.44 3.27 3.59 3.35 27 1.82 2.24 2.52 2.70 2.88 2.93 3.26 3.16 3.40 3.23 28 1.72 2.16 2.38 2.60 2.72 2.82 3.08 3.04 3.22 3.11 29 1.61 2.06 2.24 2.49 2.56 2.70 2.90 2.91 3.03 2.98 30 1.51 1.97 2.10 2.38 2.40 2.58 2.72 2.77 2.84 2.84 31 1.41 1.92 1.96 2.33 2.24 2.53 2.54 2.72 2.65 2.79 32 1.31 1.87 1.82 2.28 2.08 2.48 2.36 2.67 2.46 2.74 33 1.21 1.82 1.68 2.23 1.92 2.43 2.18 2.62 2.27 2.69 34 1.11 1.72 1.54 2.18 1.76 2.38 1.99 2.57 2.08 2.64 35 1.01 1.60 1.40 2.12 1.60 2.32 1.81 2.52 1.89 2.59 36 0.91 1.48 1.26 2.07 1.44 2.27 1.63 2.47 1.70 2.54 37 0.81 1.37 1.12 2.02 1.28 2.22 1.45 2.42 1.51 2.49 38 0.71 1.25 0.98 1.97 1.12 2.17 1.27 2.37 1.32 2.44 39 0.61 1.13 0.84 1.92 0.96 2.12 1.09 2.32 1.13 2.39 40 0.50 1.02 0.70 1.87 0.80 2.07 0.91 2.27 0.95 2.34 41 0.40 0.89 0.56 1.82 0.64 2.02 0.73 2.22 0.76 2.29 42 0.30 0.78 0.42 1.73 0.48 1.97 0.54 2.17 0.57 2.24 43 0.20 0.65 0.28 1.62 0.32 1.92 0.36 2.12 0.38 2.19 44 0.10 0.55 0.14 1.50 0.16 1.87 0.18 2.07 0.19 2.14 45 0.00 0.50 0.00 1.38 0.00 1.82 0.00 2.02 0.00 2.09 46 0.00 0.45 0.00 1.27 0.00 1.73 0.00 1.97 0.00 2.04 47 0.00 0.41 0.00 1.15 0.00 1.62 0.00 1.92 0.00 1.99 48 0.00 0.38 0.00 1.03 0.00 1.50 0.00 1.87 0.00 1.94 49 0.00 0.37 0.00 0.91 0.00 1.38 0.00 1.82 0.00 1.89 50 0.00 0.36 0.00 0.80 0.00 1.26 0.00 1.73 0.00 1.84 51 0.00 0.35 0.00 0.67 0.00 1.15 0.00 1.61 0.00 1.76 52 0.00 0.33 0.00 0.56 0.00 1.03 0.00 1.49 0.00 1.65 53 0.00 0.27 0.00 0.50 0.00 0.91 0.00 1.38 0.00 1.53 54 0.00 0.19 0.00 0.46 0.00 0.80 0.00 1.26 0.00 1.41 55 0.00 0.13 0.00 0.42 0.00 0.67 0.00 1.14 0.00 1.30 56 0.00 0.10 0.00 0.39 0.00 0.56 0.00 1.03 0.00 1.18 57 0.00 0.07 0.00 0.37 0.00 0.50 0.00 0.91 0.00 1.06 Pre Post Pre Post Pre Post Pre Post Pre Post 2yr 2yr 10yr 10yr 25yr 25yr 50yr 50yr 100yr 100yr 58 0.00 0.05 0.00 0.36 0.00 0.46 0.00 0.79 0.00 0.94 59 0.00 0.04 0.00 0.35 0.00 0.42 0.00 0.66 0.00 0.83 60 0.00 0.03 0.00 0.34 0.00 0.39 0.00 0.56 0.00 0.70 61 0.00 0.03 0.00 0.28 0.00 0.37 0.00 0.50 0.00 0.59 62 0.00 0.02 0.00 0.20 0.00 0.36 0.00 0.46 0.00 0.51 63 0.00 0.02 0.00 0.14 0.00 0.35 0.00 0.42 0.00 0.47 64 0.00 0.02 0.00 0.10 0.00 0.34 0.00 0.39 0.00 0.43 65 0.00 0.01 0.00 0.07 0.00 0.28 0.00 0.37 0.00 0.39 66 0.00 0.01 0.00 0.06 0.00 0.20 0.00 0.36 0.00 0.38 67 0.00 0.01 0.00 0.04 0.00 0.14 0.00 0.35 0.00 0.36 68 0.00 0.01 0.00 0.03 0.00 0.10 0.00 0.33 0.00 0.35 69 0.00 0.01 0.00 0.03 0.00 0.07 0.00 0.28 0.00 0.34 70 0.00 0.01 0.00 0.02 0.00 0.05 0.00 0.19 0.00 0.30 71 0.00 0.01 0.00 0.02 0.00 0.04 0.00 0.14 0.00 0.22 72 0.00 0.01 0.00 0.02 0.00 0.03 0.00 0.10 0.00 0.15 73 0.00 0.01 0.00 0.01 0.00 0.03 0.00 0.07 0.00 0.11 74 0.00 0.01 0.00 0.01 0.00 0.02 0.00 0.05 0.00 0.08 75 0.00 0.00 0.00 0.01 0.00 0.02 0.00 0.04 0.00 0.06 76 0.00 0.00 0.00 0.01 0.00 0.02 0.00 0.03 0.00 0.05 77 0.00 0.00 0.00 0.01 0.00 0.01 0.00 0.03 0.00 0.04 78 0.00 0.00 0.00 0.01 0.00 0.01 0.00 0.02 0.00 0.03 79 0.00 0.00 0.00 0.01 0.00 0.01 0.00 0.02 0.00 0.02 80 0.00 0.00 0.00 0.01 0.00 0.01 0.00 0.02 0.00 0.02 81 0.00 0.00 0.00 0.01 0.00 0.01 0.00 0.01 0.00 0.02 82 0.00 0.00 0.00 0.01 0.00 0.01 0.00 0.01 0.00 0.01 83 0.00 0.00 0.00 0.00 0.00 0.01 0.00 0.01 0.00 0.01 84 0.00 0.00 0.00 0.00 0.00 0.01 0.00 0.01 0.00 0.01 85 0.00 0.00 0.00 0.00 0.00 0.01 0.00 0.01 0.00 0.01 86 0.00 0.00 0.00 0.00 0.00 0.01 0.00 0.01 0.00 0.01 87 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.01 0.00 0.01 88 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.01 0.00 0.01 89 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.01 0.00 0.01 90 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.01 0.00 0.01 91 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.01 92 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 93 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 94 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 95 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 96 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 97 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 98 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 99 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 100 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 101 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 102 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 103 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 104 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 105 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 106 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 107 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 108 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 109 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 110 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 111 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 112 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 113 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 114 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 115 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 116 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 T> • N N +,,, ++ C C a� E Q • 0 O a) > > a) a) 0 c, a a 0 0 — o T Ci t Q. f0 0.0 O o 13 DO 2 4 C QJ V o E 0. x o L 7u co a 1 cu Ln L 1 . 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Q ®, ••• ! o o a - E a - °0 E L / a F= `ca / r 0 / o m 0 r 0 / N Lf1 +/ 0 Maw 3 O O 0 00 00 O O ip N (sp)aaie1psia Drainage Report for SECOND STREET APARTMENTS COLLEGE STATION, TEXAS January 2015 Owner: CS Second Street Apartments II, LLC 16800 Westgrove Drive, Suite 600 Addison, Texas 75001 Developer: Seneca Investments 16800 Westgrove Drive, Suite 100 Addison, Texas 75001 Prepared BY: Schultz Engineering, LLC TBPE Firm No. 12327 P.O. Box 11995 College Station, TX 77842 2730 Longmire Drive, Suite A College Station, Texas 77845 (979) 764-3900 Drainage Report—Executive Summary Second Street Apartments College Station,Texas ENGINEER Schultz Engineering,LLC P.O.Box 11995 College Station,Texas 77842 Phone:(979)764—3900 OWNER CS Second Street Apartments II,LLC 16800 Westgrove Drive,Suite 600 Addison,Texas 75001 DEVELOPER Seneca Investments 16800 Westgrove Drive,Suite 100 Addison,Texas 75001 Phone:(214)265-8686 GENERAL DESCRIPTION AND LOCATION This project consists of the redevelopment of Lots 1-8,Block 20 of the W.C.Boyett Estate Partition in College Station,Texas. This NG-3 zoned site project will include the construction of a multi-family building,parking garage,sitework,utilities and other infrastructure. This project is at the corner of Second Street and Cherry Street,as well as,the corner of Cherry Street and Boyett Street. Site Area:0.901 Existing Land Use:NG-3 Proposed Land Use:NG-3 Number of Lots: 8 Drainage Basin:Burton Creek Watershed FEMA FIRM:#48041C0305F,Dated April 2,2014 Floodplain:None of the development lies within the floodplain. HYDROLOGIC CHARACTERISTICS The pre-development condition of the land was developed with single family and duplex housing and driveways.Exhibit A shows the pre-development and post development drainage areas and the runoff flow direction.The existing flow patterns show that a majority of the property drains southwest toward the Cherry Street/Boyett Street corner,eventually entering the right-of-way being conveyed as surface flow down Boyett Street to a tributary of Burton Creek. GENERAL STORMWATER PLAN The drainage plan for this development will involve the installation of an onsite underground detention facility. The vault will be located under the first level parking garage on the Boyett Street side of the Page 1 of 5 Drainage Report—Executive Summary Second Street Apartments College Station,Texas project. The storm water runoff from roof,building and parking garages will be collected and conveyed through the detention facility. The detention facility will have outfall structure on the outside of the structure and discharge into a proposed storm sewer system to be installed in Boyett Street to the Burton Creek Tributary outfall. The proposed detention facility will capture the proposed storm runoff and discharge at a rate equal to or less than the existing design flows. A small portion of the area from the building to the back of curb will bypass the detention facility and discharge directly into the surrounding streets similar to existing flow patterns. The combination of area bypassing the detention facility and the detention facility outflow will be less than or equal to the pre-developed condition for the site. Exhibit B shows the post-development topography and the runoff flow direction. COORDINATION&STORMWATER PERMITTING The project will not require a permit to be prepared to comply with the Texas Commission for Environmental Quality storm water permitting for the construction site,because the site is less than 1 acre. No other permits are anticipated for this project. DRAINAGE DESIGN General Information: Stormwater runoff from the development will be collected and routed through the detention facility and then discharged into the proposed storm sewer system to be installed in Boyett Street.A portion of the lot,the area between the building and back of curb will bypass the detention facility and discharge directly into the surrounding streets similar to existing flow patterns. The combination of area bypassing the detention facility and the detention facility outflow will be less than or equal to the pre-developed condition for the site. The runoff enters the detention facility from a series of storm sewer pipes. Detention Facility Analysis T,Methodology: TR 55 TT Minimum: 10 minutes Design Storm Events: 2-year, 10-year,25-year,50-year and 100-year detention facility 10-year design& 100-year analysis for public storm sewer system Pond Discharge Pipe &Public Storm Sewer Materials: Class III RCP,Profile Gasket in accordance with ASTM C443,ASTM C76 Manning's n Value: 0.013 Runoff Coefficients: 0.55 for existing conditions,0.92 for developed conditions contributing to detention facility&0.72 for developed conditions contributing directly offsite. Design Constraints: Max.water depth in the parking lot=6 in.or 0.5 ft.for 100 year storm event. Min.flow velocity=2.5 fps Max.flow velocity= 15 fps Post-Development peak runoff less than or equal to existing storm water runoff from the site. Page 2 of 5 Drainage Report—Executive Summary Second Street Apartments College Station,Texas Rational Equation: The rational equation is utilized to determine peak storm water runoff rates for the Detention Facility design. Q=CIA Q=Flow(cfs) A=Area(acres) C=Runoff Coefficient I=Rainfall Intensity(in/hr) Design Software: Excel spreadsheets,AutoCAD Hydraflow Express,AutoCAD Hydraflow Hydrographs Extension The software was used to compute the pond storage and discharge data and the pre and post-development peak runoffs and the routing of the flow through the detention facility. The requirement for a 25%reduction in cross sectional area of pipes 24"in diameter or less is achieved by using internal pipe diameters that are less than the standard diameter. The 18"diameter pipe areas were reduced by 25%and a 15.6"diameter pipe was used in the analysis. Design Results: The data presented in the Appendices and in the following tables indicates the detention facility sizing and discharges are in accordance with the requirements of the design guidelines. Refer to Appendix B for design calculations for the storm sewer pipes. Applicable Exhibits: Exhibit A—Pre-development Drainage Area Map Exhibit B—Post-development Drainage Area Map Appendix A—Drainage Area Summary—Detention Facility Appendix B—Pipe Design Summary Appendix C—Detention Facility Data and Hydrographs Design Analysis: The post-development drainage areas are shown on Exhibit B. The design data and descriptions of the detention facility outlet structures,discharge pipes and overflow spillways are found in Appendix C. A portion of site between the building and back of curb will bypass the detention facility and discharge directly into the surrounding streets similar to existing flow patterns. The combination of area bypassing the detention facility and the detention facility outflow will be less than or equal to the pre-developed condition. Sedimentation in the detention facility is not likely due to the small drainage areas that are mostly paved areas and the use of underground detention in storm sewer pipes.However,the design storage capacity of the detention facility was increased by 10%in the event that sediment does build up. The peak flow out of the detention facility was determined by a Storage Routing Analysis based on the Continuity Equation as follows:(I1+I2)+((2s1/dt)- 01)=((2s2/dt)=O2). The time interval,dt,used was 1 minute. The calculations and results of the Storage Routing Analysis were used to generate hydrograph peak flows and graphs for the pre and post development conditions. A summary of the pre and post development runoff information from the site is shown in Table 2. Page 3 of 5 Drainage Report-Executive Summary Second Street Apartments College Station,Texas The flow out of the detention facility is controlled by an 8"x 8"orifice and a 3' wide rectangular weir located in the detention facility outlet structure. The rim of the outlet structure is 343.94'. The detention facility discharges into a proposed storm sewer system to be installed in Boyett Street. TABLE 1-Pre-&Post-Development Runoff Input Information Tc Area# Area (Acres) C (Min.) Pre 101 1.05 0.55 15 Post 201 0.83 0.92 10 Post 202 0.22 0.72 10 TABLE 2-Pre-&Post-Development Runoff Comparison-Detention Analysis Q2 Q10 Q25 Q50 Q100 Location cfs cfs cfs cfs cfs Pre-Development 3.00 4.15 4.76 5.39 5.62 (Area 101) Post Development with Detention Post-Development 4.83 6.59 7.53 8.51 8.89 (Area 201) Post-Development 1.00 1.37 1.56 1.77 1.84 (Area 202) Detention Facility Outfall 2.19 2.57 2.78 2.95 3.16 (Area 201 Routed Through Facility) Combined Outflow 2.85 3.42 3.72 4.03 4.14 (Compare to Area 101) Decrease in Peak Flow 0.15 0.73 1.04 1.36 1.48 As shown in Table 2,the post-development peak outflow from the project site is less than the allowable peak outflow for each design storm event. Additionally, Tables 3 presents the maximum water surface and the amount of freeboard for the Detention Facility. The peak flow out of the detention facility and the maximum water surface was determined by the Storage Routing Analysis. Page 4 of 5 Drainage Report—Executive Summary Second Street Apartments College Station,Texas The proposed 18"diameter storm sewer pipe to be constructed in Boyett Street has a capacity greater than the maximum detention facility discharge rate of 3.16 cfs,as shown in Appendix B. TABLE 3—Summary of Detention Facility Maximum Water Surface Levels Peak Flow out of Water Surface Freeboard Storm Event Facility,(cfs) Elevation,ft. ft. 2-year 2.19 341.53 2.47 10-year 2.57 342.17 1.83 25-year 2.78 342.53 1.47 50-year 2.95 342.91 1.09 100-year 3.16 343.05 0.95 The 100 year water surface is below the rim elevation of the outfall structure. If the pond outlet orifice clogs,the water will discharge through the 3' wide rectangular weir. CONCLUSION The onsite detention facility for the development will function within the requirements and restrictions of the BCS Drainage Design Guidelines. CERTIFICATION "This report for the drainage design of the Second Street Apartments was prepared by me in accordance with the provisions of the Bryan/College Station Unified Drainage Design Guidelines for the owners of the property. All licenses and permits required by any and all state and federal regulatory agencies for the proposed drainage improvements have been issued." I'���P� OF � •. ' Deven L.Doyen,P.E. 1 �— DEVEN L. DOYEN 109835 / �FSSi � Nfat- , FIRM # 1232 7 Page 5 of 5 SCHULTZ ENGINEERING, LLC EXHIBIT A Pre-Development Drainage Area Map 111111. 0 20 40 SCALE IN FEET I I I 1 I 1 1 i I � L 1 1 'w 1 I / > > / I 1 / I \ / t ti / \ / f ) / / \ L / f / / / s / „--- '71 { i Schultz En! SCALE EXHIBIT LOENT vERT1cAL ® © STRONG surR D m 4REA A 4 p HORIZ01� � EXHIBIT B Post-Development Drainage Area Map • • STANDARD STOR INLET RING: COVER M IN= NMI 0 20 40 3'WADE WI- ' ////f////% • 343.91' SCALE IN FEET 0.45' �1111111111111111111 ► . 343.00' e1NTn9aOPOROPGy"" 1D14 N �1t1 � 1I4 ♦11♦*1111 18•R.* ��1:1:1�11�11J.5 STORM SEVER ,1�14,1.1� 40 I 1' � '► 111 Y.�:----i#!i . 339.50' ISECTION 13-8 4'TREE NELL STORM DRAIN PIPE /' I I I 1 8•RCP STORM SEWER i 1 %I In A I , L 1 TS TET RING \I PoNC: COVER ..? I 'TREE NELL STORM DR"\ IN I1 1'1.1\171:1\ I , , STANDARD S*- / INLET RING: COVER -8 ``t P. 1 // A I ELEV: 343.94' GDNGRETE 1 / x8 OFBFlCE _ant 313.00' 1 \ // / 1 1 R- _0.5' 1.25' 0.5' 1.25' 0.5'� 8 RCP /L \\ _ "STORM SEVER 0 / j_ ... / // \\ L r a' 81 ) // / \ SURES VOL / / SECTION A-A , 339.50' / / / / UNDERGROUND DETENTION VAUl T ,AOUTLET STRI JenIRE DETAIL / / N.I.S. OUTFALL / / / HEADWALL/PIPE 100 / 18" RCP -., , , 0 0.40% SLOPE ~ - ST - ST - ST - ST ---§T � -,. PROPOSED JUNCTION BOX --.. _ , __._. 34/-_ 342-•" - I I I I I i ,LOPMEN SCALE EXHIBITIVERTICAL979 L_____4_____Hchultz I P PA Li A n HZ°�'� `=�01 fl APPENDIX A Drainage Area Summary—Detention Facility i S N a — a oo M nor 0 W Y V -o8 el' nor N VQ O Q\ .: 'r a.) cn * 0 8 a V on 00 r N C r.a .a > 0 y If y m O S ♦.. .a > y 0, oo C el - y H II II 'itL b nta 00 M on O 599 cn M - ^` 00 M no 00 N C'' a 5 N Y ° 00 �, N rn o06 `n - O II II II >. _ 'A .0 b 0 N L M no 000 P N 00 00 on Gl 00 O0 0' Coh h N W ^ Y r V a a 7 ^ N M 1 O Qh N. N 00 00 O ce Q II H H >, "4 .0 b ai o SD ,0 N N 06 00 7, o On co on no E a V en M v oo. O N N r N s` s o on - oo � o t' Q II II II d ? Jo b a) N1 ci M M 0' M M to 00 C 0 O .. 0 0 0 0 0 .. F. o ', o a A 5L tin y E o C ', '. ❑ y ,p 00 O Wo Z W Q II Q b p N + 0 0 .0 b a) L Vi N N5 0 43 m .`'.' E N aC+ v 0 0 0 .. 0 Lo E--h A u .. .rl S 5 a. 3 ea .0 0 0 O S yE Q W 4 O 00 N N �p '�' L N a os b0 7 C - o o . O U o O. co cip a y'' y i v .. a"i 2 U y Q A d a0 0 Q" U 4 o cip _e fl u a _ 3 3 e ,« tl L. 'O q N b o oN N 'Z 9 ii a .II II II II II cip Q 6. G F O' d Q U — APPENDIX B Pipe Design Summary E o o 00 o 0 0 0 0 8 iii a co ccoo ccoo co > ri ri ri ri N (O CO (0 Co 4- 0 O 0 ri r) ri ('Si O - 0 0 0 0 N- O 0 O O t CO Co ri CO N N- N N Ci ULn L1) Lo L1) N N N N o) C 7▪ N o a d 0 0 a o X 0 U Z Lu co w m m Q a c d 0 0 0 0 ▪ _6 Q -o D c c C c c O 0 0 0 0 0 U a_ a_ a. d m o O O O O N COt M C = cri O N d N J N N N C CO CO co a) n 'a N c C co t a6 `°a E a m co m c u) N N 0 M N O c C3 Q o O O O O o u a a z cn a APPENDIX C Detention Facility Data& Hydrographs Detention Facility Appendix C Detention Facility Summary Detention Facility Design Storm Inflow Outflow W.S.Elevation (yr) (cfs) (cfs) (ft) 2 4.83 2.19 _ ___ 341.53 __ 10 __ 6.59 2.57 342.17 __ 25 __ 7.53____ . -_2.78 __ 342.53 __ 50 __ 8.51__ __ _2.95 _ _ _ _ 342.91 __ 100 8.89 3.16 343.05 *Top of outfall structure=343.94',Weir Crest Elevation=343.00' Detention Facility Appendix C Detention Facility Area-Capacity Data Detention Facility Storage 90% Elevation Depth Volume Cumulative Cumulative Volume Volume (ft) (ft) (ft3) (ft3) (ft3) 339.50 _ _ 0.00 0 0__ - 0 - 340.0 __ 0.50__ __ 77 _ ___77.33 _____ 70 _ _ 341.0 _ _ 1.50__ __1,083_ ___1160.5 _____1,055_ _ 342.0 __ 2.50__ __1,856_ __ 71.3016.2 2,742_ _ 343.0 _ _ 3.501,856 __489 _________4,429_ _ 344.0 4.50_ _ __1,857 6728.7 6,117 Detention Facility Appendix C Elevation-Discharge Data Depth-Discharge Data 8" x 8" 3' Rectangular Facility Orifice Weir Total Design Elevation Depth Flow Spillway Flow (ft) (ft) (cfs) (cfs) (cfs) 339.5 0.0 0.00 0.00 0.00 340.0 0.5 0.33 0.00 0.33 341.0 1.5 1.82 0.00 1.82 342.0 2.5 2.47 0.00 2.47 343.0 3.5 2.99 0.00 2.99 344.0 4.5 3.43 9.99 13.42 Notes: 1. The Outlet Structure is a junction box with a 8"x 8" Orifice and a 3'Wide Rectangular Weir 2. The rectangular spillway will serve as the overflow spillway. Detention Facility Plugged Condition The 100 year water surface is below the rim elevations of the outlet structure.If the facility outlet orifice clogs,the water will discharge through the 3'wide rectangular weir. Detention Facility Appendix C Storage Routing Analysis Parameters t=60s Detention Facility Elevation Depth Discharge Storage 2 s/t 2 s/t+0 (ft) (ft) (O,cfs) (s,cf) 339.50 0.0 0.00 0.0 0.0 0.00 340.00 0.5 0.33 70.3 2.3 2.67 341.00 1.5 1.82 1055.0 35.2 36.98 342.00 2.5 2.47 2742.0 91.4 93.87 343.00 3.5 2.99 4429.0 147.6 150.62 344.00 4.5 13.42 6117.0 203.9 217.32 * The flow control structure for the smaller storms is an 8"x8" orifice and a 3'wide rectangular weir. Detention Facility Inflow&Outflow Hydrographs Appendix C Inflow Outflow Inflow Outflow Inflow Outflow Inflow Outflow Inflow Outflow 2yr 2yr 10yr , 10yr 25yr 25yr 50yr 50yr 100yr 100yr Time(min) Q(cfs) Q(cfs) Q(cfs) Q(cfs) Q(cfs) Q(cfs) Q(cfs) Q(cfs) Q(cfs) Q(cfs) 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 I 0.48 0.03 0.66 0.05 0.75 0.06 0.85 0.07 0.89 0.07 2 0.97 0.22 1.32 0.31 1.51 0.33 1.70 0.34 1.78 0.34 3 1.45 0.35 1.98 0.37 2.26 0.39 2.55 0.42 2.67 0.44 4 1.93 0.41 2.64 0.52 3.01 0.62 3.40 0.73 3.56 0.78 5 2.42 0.58 3.30 0.88 3.77 1.00 4.26 1.11 4.44 1.15 6 2.90 0.89 3.96 1.17 4.52 1.30 5.11 1.42 5.33 1.47 7 3.38 1.14 4.62 1.44 5.27 1.58 5.96 1.72 6.22 1.76 8 3.86 1.36 5.27 1.69 6.02 1.82 6.81 1.89 7.11 1.92 9 4.35 1.57 5.93 1.86 6.78 1.94 7.66 2.03 8.00 2.06 10 4.83 1.77 6.59 1.98 7.53 ,;. 2.07 8.51 2.17 8.89 2.21 11 4.59 1.87 6.26 2.09 7.15 2.20 8.09 2.31 8.44 2.35 12 4.35 1.94 5.93 2.18 6.78 2.30 7.66 2.42 8.00 2.47 13 4.11 2.00 5.60 2.26 6.40 2.39 7.24 2.53 7.55 2.57 14 3.86 2.04 5.27 2.33 6.02 2.47 6.81 2.61 7.11 2.67 15 3.62 2.09 4.94 2.39 5.65 2.54 6.38 2.69 6.67 2.74 16 3.38 2.12 4.62 2.44 5.27 2.59 5.96 2.75 6.22 2.81 17 3.14 2.15 4.29 2.48 4.89 2.64 5.53 2.80 5.78 2.87 18 2.90 2.17 3.96 2.51 4.52 2.68 5.11 2.85 5.33 2.91 19 2.66 2.18 3.63 2.53 4.14 2.71 4.68 2.88 4.89 2.95 20 2.42 2.19 3.30 2.55 3.77 2.73 4.26 2.91 4.44 2.98 21 2.17 2.19 2.97 2.56 3.39 2.75 3.83 2.93 4.00 3.05 22 1.93 2.11 2.64 2.57 3.01 2.76 3.40 2.94 3.56 3.14 23 1.69 2.18 2.31 2.57 2.64 2.76 2.98 2.95 3.11 3.16 24 1.45 2.16 1.98 2.56 2.26 2.75 2.55 2.94 2.67 3.13 25 1.21 2.15 1.65 2.54 1.88 2.74 2.13 2.93 2.22 3.05 26 0.97 2.12 1.32 2.52 1.51 2.72 1.70 2.92 1.78 2.98 27 0.72 2.09 0.99 2.50 1.13 2.69 1.28 2.89 1.33 2.96 28 0.48 2.06 0.66 2.46 0.75 2.66 0.85 2.86 0.89 2.93 29 0.24 2.01 0.33 2.42 0.38 2.62 0.43 2.82 0.44 2.89 30 0.00 1.97 0.00 2.38 0.00 2.58 0.00 2.77 0.00 2.84 31 0.00 1.92 0.00 2.33 0.00 2.53 0.00 2.72 0.00 2.79 32 0.00 1.87 0.00 2.28 0.00 2.48 0.00 2.67 0.00 2.74 33 0.00 1.82 0.00 2.23 0.00 2.43 0.00 2.62 0.00 2.69 34 0.00 1.72 0.00 2.18 0.00 2.38 0.00 2.57 0.00 2.64 35 0.00 1.60 0.00 2.12 0.00 2.32 0.00 2.52 0.00 2.59 36 0.00 1.48 0.00 2.07 0.00 2.27 0.00 2.47 0.00 2.54 37 0.00 1.37 0.00 2.02 0.00 2.22 0.00 2.42 0.00 2.49 38 0.00 1.25 0.00 1.97 0.00 2.17 0.00 2.37 0.00 2.44 39 0.00 1.13 0.00 1.92 0.00 2.12 0.00 2.32 0.00 2.39 40 0.00 1.02 0.00 1.87 0.00 2.07 0.00 2.27 0.00 2.34 41 0.00 0.89 0.00 1.82 0.00 2.02 0.00 2.22 0.00 2.29 42 0.00 0.78 0.00 1.73 0.00 1.97 0.00 2.17 0.00 2.24 43 0.00 0.65 0.00 1.62 0.00 1.92 0.00 2.12 0.00 2.19 44 0.00 0.55 0.00 1.50 0.00 1.87 0.00 2.07 0.00 2.14 45 0.00 0.50 0.00 1.38 0.00 1.82 0.00 2.02 0.00 2.09 46 0.00 0.45 0.00 1.27 0.00 1.73 0.00 1.97 0.00 2.04 47 0.00 0.41 0.00 1.15 0.00 1.62 0.00 1.92 0.00 1.99 48 0.00 0.38 0.00 1.03 0.00 1.50 0.00 1.87 0.00 1.94 49 0.00 0.37 0.00 0.91 0.00 1.38 0.00 1.82 0.00 1.89 50 0.00 0.36 0.00 0.80 0.00 1.26 0.00 1.73 0.00 1.84 51 0.00 0.35 0.00 0.67 0.00 1.15 0.00 1.61 0.00 1.76 52 0.00 0.33 0.00 0.56 0.00 1.03 0.00 1.49 0.00 1.65 53 0.00 0.27 0.00 0.50 0.00 0.91 0.00 1.38 0.00 1.53 54 0.00 0.19 0.00 0.46 0.00 0.80 0.00 1.26 0.00 1.41 55 0.00 0.13 0.00 0.42 0.00 0.67 0.00 1.14 0.00 1.30 56 0.00 0.10 0.00 0.39 0.00 0.56 0.00 1.03 0.00 1.18 57 0.00 0.07 0.00 0.37 0.00 0.50 0.00 0.91 0.00 1.06 Inflow Outflow Inflow Outflow Inflow Outflow Inflow Outflow Inflow Outflow 2yr 2yr l0yr 10yr 25yr 25yr 50yr 50yr 100yr 100yr 58 0.00 0.05 0.00 0.36 0.00 0.46 0.00 0.79 0.00 0.94 59 0.00 0.04 0.00 0.35 0.00 0.42 0.00 0.66 0.00 0.83 60 0.00 0.03 0.00 0.34 0.00 0.39 0.00 0.56 0.00 0.70 61 0.00 0.03 0.00 0.28 0.00 0.37 0.00 0.50 0.00 0.59 62 0.00 0.02 0.00 0.20 0.00 0.36 0.00 0.46 0.00 0.51 63 0.00 0.02 0.00 0.14 0.00 0.35 0.00 0.42 0.00 0.47 64 0.00 0.02 0.00 0.10 0.00 0.34 0.00 0.39 0.00 0.43 65 0.00 0.01 0.00 0.07 0.00 0.28 0.00 0.37 0.00 0.39 66 0.00 0.01 0.00 0.06 0.00 0.20 0.00 0.36 0.00 0.38 67 0.00 0.01 0.00 0.04 0.00 0.14 0.00 0.35 0.00 0.36 68 0.00 0.01 0.00 0.03 0.00 0.10 0.00 0.33 0.00 0.35 69 0.00 0.01 0.00 0.03 0.00 0.07 0.00 0.28 0.00 0.34 70 0.00 0.01 0.00 0.02 0.00 0.05 0.00 0.19 0.00 0.30 71 0.00 0.01 0.00 0.02 0.00 0.04 0.00 0.14 0.00 0.22 72 0.00 0.01 0.00 0.02 0.00 0.03 0.00 0.10 0.00 0.15 73 0.00 0.01 0.00 0.01 0.00 0.03 0.00 0.07 0.00 0.11 74 0.00 0.01 0.00 0.01 0.00 0.02 0.00 0.05 0.00 0.08 75 0.00 0.00 0.00 0.01 0.00 0.02 0.00 0.04 0.00 0.06 76 0.00 0.00 0.00 0.01 0.00 0.02 0.00 0.03 0.00 0.05 77 0.00 0.00 0.00 0.01 0.00 0.01 0.00 0.03 0.00 0.04 78 0.00 0.00 0.00 0.01 0.00 0.01 0.00 0.02 0.00 0.03 79 0.00 0.00 0.00 0.01 0.00 0.01 0.00 0.02 0.00 0.02 80 0.00 0.00 0.00 0.01 0.00 0.01 0.00 0.02 0.00 0.02 81 0.00 0.00 0.00 0.01 0.00 0.01 0.00 0.01 0.00 0.02 82 0.00 0.00 0.00 0.01 0.00 0.01 0.00 0.01 0.00 0.01 83 0.00 0.00 0.00 0.00 0.00 0.01 0.00 0.01 0.00 0.01 84 0.00 0.00 0.00 0.00 0.00 0.01 0.00 0.01 0.00 0.01 85 0.00 0.00 0.00 0.00 0.00 0.01 0.00 0.01 0.00 0.01 86 0.00 0.00 0.00 0.00 0.00 0.01 0.00 0.01 0.00 0.01 87 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.01 0.00 0.01 88 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.01 0.00 0.01 89 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.01 0.00 0.01 90 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.01 0.00 0.01 91 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.01 92 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 93 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 94 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 95 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 96 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 97 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 98 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 99 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 100 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 101 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 102 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 103 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 104 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 105 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 106 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 107 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 108 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 109 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 110 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 111 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 112 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 113 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 114 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 115 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 116 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 L T N N 0 o c O ? T 'u u ca u- LL 0 <-1 e-1 - O O '-1 I. 0 Q1 .c C. ea L o - 00 2 oO N K O 'O W 5 3 �- o a c / o, 1 } o r N I' 7-41 / m N 0 N C co • o 0 0 0 0 (sp)aaie43s!a L 0 O -1 0 o 9 7 5 O T T u u CU CO LL LL O .--1 0 0 Oo1 Vf - 0. L O _ 0 000 r u j x = t. aO o a 1 _ iD o ra LL >- 0 o / - / o n tn N O t u1 ` �p • o •O O O CO (sp) ey3sia tr) N N 3 a O w- 7 c O T ? Y Y u u co co LL LL 0 O o ei H ` Oo1 .c a. Io a — o X 0 't (.1 o O x /, off c / - ai 3 a ' 0 a I tu 0 Lin CO N / / o m N _ O 1 N M , V1 ` n O _ - o 0 0 0 0 0 pp tri N O (sp)a2ieyxia 0 L- >`• '^ L^ 3 0 O , w- z c O > > u u fo tL LL I y� 0 — '-I 0 - 0 .-i 0 L O. f0 LO 0 00 2 0 / o Ox o�S c I CLO . / c c Q / E / E o ro U L / o I In / / o m m N - 1 ._ o a-i CO % _ o • 9111., .._..__....1_._._._y_._.._..1_...........t.._............_......1... - 0 O 0 0 0 0 0 0 00 u; v ni o (sp)a2ieipsia ` 5, 0 0 0 � 3 0 o 5 C O T T Y Y 'u 'u CO CO LL LL I ' I - 0 •--I 0 - 0 a-1 V, t O Ol V 2 00 o 1 o X j o otf -a - 3 / o a c Q / • `° c / E / a, / E LL o 4- // o rsi Oo • ao ` •0 0 0 0 0 0 0 00 l0 a N o '-I (sp)a8.JeLpsuc Pre-Development VS.Post Development Hydrographs Appendix C Pre Post Pre Post Pre Post Pre Post Pre Post 2yr 2yr l0yr 10yr 25yr 25yr 50yr 50yr 100yr 100yr Time(min) Q(cfs) Q(cfs) Q(cfs) Q(cfs) Q(cfs) Q(cfs) Q(cfs) Q(cfs) Q(cfs) Q(cfs) 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 I 0.20 0.13 0.28 0.18 0.32 0.21 0.36 0.25 0.38 0.26 2 0.40 0.42 0.56 0.59 0.64 0.65 0.73 0.69 0.76 0.71 3 0.61 0.65 0.84 0.78 0.96 0.86 1.09 0.95 1.13 0.99 4 0.81 0.81 1.12 1.07 1.28 1.24 1.45 1.44 1.51 1.52 5 1.01 1.09 1.40 1.56 1.60 1.78 1.81 1.99 1.89 2.07 6 1.21 1.49 1.68 2.00 1.92 2.24 2.18 2.48 2.27 2.58 7 1.41 1.84 1.96 2.40 2.24 2.68 2.54 2.96 2.65 3.05 8 1.61 2.16 2.24 2.79 2.56 3.07 2.90 3.31 3.03 3.39 9 1.82 2.47 2.52 3.09 2.88 3.35 3.26 3.62 3.40 3.72 10 2.02 2.77 2.80 3.34 3.20 3.64 3.63 3.94 3.78 4.05 11 2.22 2.82 3.08 3.38 3.52 3.68 3.99 3.99 4.16 4.10 12 2.42 2.84 3.36 3.41 3.84 3.71 4.35 4.01 4.54 4.13 13 2.62 2.85 3.63 3.42 4.16 3.72 4.71 4.03 4.92 4.14 14 2.83 2.85 3.91 3.42 4.48 3.72 5.08 4.02 5.30 4.14 15, 3.03 2.84 AA 3.41 4.80 3.71 544 4.01 5.67 4.13 16 2.93 2.82 4.05 3.39 4.64 3.69 5.26 3.99 5.48 4.10 17 2.83 2.80 3.91 3.37 4.48 3.66 5.08 3.95 5.30 4.06 18 2.72 2.77 3.77 3.33 4.32 3.62 4.89 3.91 5.11 4.02 19 2.62 2.73 3.63 3.29 4.16 3.57 4.71 3.86 4.92 3.96 20 2.52 2.69 3.50 3.24 4.00 3.51 4.53 3.79 4.73 3.90 21 2.42 2.64 3.36 3.18 3.84 3.45 4.35 3.73 4.54 3.88 22 2.32 2.59 3.22 3.12 3.68 3.38 4.17 3.65 4.35 3.87 23 2.22 2.53 3.08 3.05 3.52 3.30 3.99 3.56 4.16 3.81 24 2.12 2.47 2.94 2.97 3.36 3.22 3.81 3.47 3.97 3.68 25 2.02 2.40 2.80 2.89 3.20 3.13 3.63 3.38 3.78 3.51 26 1.92 2.32 2.66 2.80 3.04 3.03 3.44 3.27 3.59 3.35 27 1.82 2.24 2.52 2.70 2.88 2.93 3.26 3.16 3.40 3.23 28 1.72 2.16 2.38 2.60 2.72 2.82 3.08 3.04 3.22 3.11 29 1.61 2.06 2.24 2.49 2.56 2.70 2.90 2.91 3.03 2.98 30 1.51 1.97 2.10 2.38 2.40 2.58 2.72 2.77 2.84 2.84 31 1.41 1.92 1.96 2.33 2.24 2.53 2.54 2.72 2.65 2.79 32 1.31 1.87 1.82 2.28 2.08 2.48 2.36 2.67 2.46 2.74 33 1.21 1.82 1.68 2.23 1.92 2.43 2.18 2.62 2.27 2.69 34 1.11 1.72 1.54 2.18 1.76 2.38 1.99 2.57 2.08 2.64 35 1.01 1.60 1.40 2.12 1.60 2.32 1.81 2.52 1.89 2.59 36 0.91 1.48 1.26 2.07 1.44 2.27 1.63 2.47 1.70 2.54 37 0.81 1.37 1.12 2.02 1.28 2.22 1.45 2.42 1.51 2.49 38 0.71 1.25 0.98 1.97 1.12 2.17 1.27 2.37 1.32 2.44 39 0.61 1.13 0.84 1.92 0.96 2.12 1.09 2.32 1.13 2.39 40 0.50 1.02 0.70 1.87 0.80 2.07 0.91 2.27 0.95 2.34 41 0.40 0.89 0.56 1.82 0.64 2.02 0.73 2.22 0.76 2.29 42 0.30 0.78 0.42 1.73 0.48 1.97 0.54 2.17 0.57 2.24 43 0.20 0.65 _ 0.28 1.62 0.32 1.92 0.36 2.12 0.38 2.19 44 0.10 0.55 0.14 1.50 0.16 1.87 0.18 2.07 0.19 2.14 45 0.00 0.50 0.00 1.38 0.00 1.82 0.00 2.02 0.00 2.09 46 0.00 0.45 0.00 1.27 0.00 1.73 0.00 1.97 0.00 2.04 47 0.00 0.41 0.00 1.15 0.00 1.62 0.00 1.92 0.00 1.99 48 0.00 0.38 0.00 1.03 0.00 1.50 0.00 1.87 0.00 1.94 49 0.00 0.37 0.00 0.91 0.00 1.38 0.00 1.82 0.00 1.89 50 0.00 0.36 0.00 0.80 0.00 1.26 0.00 1.73 0.00 1.84 51 0.00 0.35 0.00 0.67 0.00 1.15 0.00 1.61 0.00 1.76 52 0.00 0.33 0.00 0.56 0.00 1.03 0.00 1.49 0.00 1.65 53 0.00 0.27 0.00 0.50 0.00 0.91 0.00 1.38 0.00 1.53 54 0.00 0.19 0.00 0.46 0.00 0.80 0.00 1.26 0.00 1.41 55 0.00 0.13 0.00 0.42 0.00 0.67 0.00 1.14 0.00 1.30 56 0.00 0.10 0.00 0.39 0.00 0.56 0.00 1.03 0.00 1.18 57 0.00 0.07 0.00 0.37 0.00 0.50 0.00 0.91 0.00 1.06 Pre Post Pre Post Pre Post Pre Post Pre Post 2yr 2yr 10yr 10yr 25yr 25yr 50yr 50yr 100yr I00yr 58 0.00 0.05 0.00 0.36 0.00 0.46 0.00 0.79 0.00 0.94 59 0.00 0.04 0.00 0.35 0.00 0.42 0.00 0.66 0.00 0.83 60 0.00 0.03 0.00 0.34 0.00 0.39 0.00 0.56 0.00 0.70 61 0.00 0.03 0.00 0.28 0.00 0.37 0.00 0.50 0.00 0.59 62 0.00 0.02 0.00 0.20 0.00 0.36 0.00 0.46 0.00 0.51 63 0.00 0.02 0.00 0.14 0.00 0.35 0.00 0.42 0.00 0.47 64 0.00 0.02 0.00 0.10 0.00 0.34 0.00 0.39 0.00 0.43 65 0.00 0.01 0.00 0.07 0.00 0.28 0.00 0.37 0.00 0.39 66 0.00 0.01 0.00 0.06 0.00 0.20 0.00 0.36 0.00 0.38 67 0.00 0.01 0.00 0.04 0.00 0.14 0.00 0.35 0.00 0.36 68 0.00 0.01 0.00 0.03 0.00 0.10 0.00 0.33 0.00 0.35 69 0.00 0.01 0.00 0.03 0.00 0.07 0.00 0.28 0.00 0.34 70 0.00 0.01 0.00 0.02 0.00 0.05 0.00 0.19 0.00 0.30 71 0.00 0.01 0.00 0.02 0.00 0.04 0.00 0.14 0.00 0.22 72 0.00 0.01 0.00 0.02 0.00 0.03 0.00 0.10 0.00 0.15 73 0.00 0.01 0.00 0.01 0.00 0.03 0.00 0.07 0.00 0.11 74 0.00 0.01 0.00 0.01 0.00 0.02 0.00 0.05 0.00 0.08 75 0.00 0.00 0.00 0.01 0.00 0.02 0.00 0.04 0.00 0.06 76 0.00 0.00 0.00 0.01 0.00 0.02 0.00 0.03 0.00 0.05 77 0.00 0.00 0.00 0.01 0.00 0.01 0.00 0.03 0.00 0.04 78 0.00 0.00 0.00 0.01 0.00 0.01 0.00 0.02 0.00 0.03 79 0.00 0.00 0.00 0.01 0.00 0.01 0.00 0.02 0.00 0.02 80 0.00 0.00 0.00 0.01 0.00 0.01 0.00 0.02 0.00 0.02 81 0.00 0.00 0.00 0.01 0.00 0.01 0.00 0.01 0.00 0.02 82 0.00 0.00 0.00 0.01 0.00 0.01 0.00 0.01 0.00 0.01 83 0.00 0.00 0.00 0.00 0.00 0.01 0.00 0.01 0.00 0.01 84 0.00 0.00 0.00 0.00 0.00 0.01 0.00 0.01 0.00 0.01 85 0.00 0.00 0.00 0.00 0.00 0.01 0.00 0.01 0.00 0.01 86 0.00 0.00 0.00 0.00 0.00 0.01 0.00 0.01 0.00 0.01 87 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.01 0.00 0.01 88 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.01 0.00 0.01 89 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.01 0.00 0.01 90 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.01 0.00 0.01 91 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.01 92 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 93 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 94 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 95 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 96 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 97 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 98 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 99 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 100 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 101 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 102 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 103 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 104 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 105 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 106 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 107 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 108 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 109 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 110 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 III 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 112 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 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