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Home My WebLink AboutDrainage ReportPRELIMINARY DRAINAGE REPORT HOME 2 SUITES HOTEL DEVELOPMENT Prepared for: City of College Station College Station Brazos County, Texas JC Job No.: C0120-001 OCTOBER 9, 2012 Prepared by: 1 JONES&CARTE R,ixc. ENGINEERS -PLANNERS -SURVEYORS TemsBa de.Rgkamt ,,Na F4" 1716 Briarcrest Dr., Suite 160 Bryan, TX 77802-2776 979-731-8000 ♦ 979-846-2893 (fax) ww Jonescarier.00m TIES DOCUMENT IS RELEASED FOR THE PURPOSE OF: REVIEW 10/09/2012 UNDER THE AUTHORITY OF STEVE E. DUNCAN, P.E. 83252 IT IS NOT TO BE USED FOR CONSTRUCTION, BIDDING, OR PERNRTTINGPRUPOSES.^^'' by j a -A I -"I 10 1Oria m, if) 1.0 EXECUTIVE SUMMARY 1.1 Engineer Contact Information Steve E. Duncan, P.E. Jones & Carter hrc. 1716 Briarcrest Drive, Suite 160 Bryan, Texas 77802 (979) 731-8000 sduncan@ionescarter.com 1.2 Project Information The Home 2 Suites (112S) development is located at 300 South Texas Avenue, College Station, Texas, on the following combination of properties totaling 1.97 acres: a. 1.41 Acre tract, Lot 2, Lodgeco Subdivision b. 0.20 Acre tract, Lot 2, North Park Section It c. 0.18 Acre tract, Lot 3, North Park Section II d. 0.18 Acre tract, Lot 4, North Park Section H These four (4) lots for an "L" shaped property with frontage on Texas Avenue and Meadowland. Additionally, the H2S development is located north of the existing Hampton but property and south and west of the existing Applebee's and south of a vacant lot located on the northwest corner of the H2S property. Please refer to Exhibit A —Overall Man for additional information. 1.3 Watershed Information The H2S property is located within in the Burton Creek Watershed Area as shown in Exhibit B — Burton Creek Watershed Area. Per the Bryan/College Station Unified Stormwater Design Guidelines (UDG) dated August 2012, this site is located in a zone that requires additional evaluation to determine the need for stormwater detention. 1.4 FEMA Information The entire property site is situated within the city its of College Station. According to community panel no. 48041CO205C of the Federal E ter ncy Management Agency's flood insurance rate maps for Brazos County, Texas, effective date Ju 1992, a subject tract is situated within unshaded zone "X", defined as areas determined to be outside the 500-year flood plain (Exhibit C —FEMA Flood Plain Map). 2.0 EXISTING CONDITIONS 2.1 Location and Topography The 112S property is located with frontage on two parallel streets, Meadowland Drive to the west and Texas Avenue to the East. The existing 4-plex lots generally slope towards Meadowland Drive with very little topographical relief resulting in small slopes. The long section of the property spanning Meadowland Drive to Texas Avenue gently slopes from elevation 330' at Meadowland to elevation 324' at Texas Avenue. 2.2 Land Use This project consists of four (4) different tracts being combined via a future replat into one (1) single 1.97 acre property. The lots remaining from the North Park subdivision currently are fully developed multi- family residential 4-plex units and concrete parking lot. The section of the property remaining from the Lodgeco Subdivision adjacent to Meadowland Drive consists of concrete parking lot for the first 100' towards Texas Avenue, transistioning to overgrown grasses with a few trees in the middle, then the concrete remains of a former building and parking lot for the 80' prior to and adjacent to Texas Avenue. 2.3. Drainage Patterns Three (3) of the existing properties are fully developed 4-plex properties including the 4-plex structure and concrete pavement for parking and access. The runoff from the existing 4-plex properties sheet flows towards Meadowland Drive. These properties include lots 2, 3, and 4 of the North Park Section II subdivision. The stormwater runoff that enters Meadowland Drive gutter flows south along Meadowland then East along Spence towards Texas Avenue discharging into Burton Creek Tributary C. Additionally, the remaining 1.41 acre lot 2 of the Lodgco Subdivision includes a concrete parking lot located along Meadowland Drive between the 4-plex properties and the Hampton Inn property, overgrown grass area, and the remaining pavement from a former development adjacent to Texas Avenue. The stormwater runoff from the 1.41 acre tract sheet flows onto Texas Avenue to an inlet and 4'x6' box culvert located east of the Applebee's property north of the subject tract. The 4'x6' box culvert then conveys the stormwater to Burton Creek Tributary C.3. 2.4 Existing Condition HEC-HMS 100-Year Storm Event Analysis O Summary Results for Sub basin "Pre -Developed Lot" Project: Home2 Suites Simulation Run: Pre too Subbasin: Pre -Developed Lot Start of Run: 09)ul2009, 12:00 Basin Model: H25 Pre Development End of Run: 10]u12009, 14:30 Meteorologic Model: 24hr - 100 yr Compute Time: 090ct2012, 09:42:13 Control Specifications: Control 1 Volume Units: 4 IN AC -FT Computed Results Peak Discharge : 10.5 (CFS) Date/Time of Peak Discharge : 10]ul2009, 00:30 Total Precipitation : (1N) Total Direct Runoff : 10.99 (IN) Total Loss : 0.36 (IN) Total Baseflon : 0.00 (IN) Total Excess : 10.99 (IN) Discharge : 10.99 (IN) 100-Year Storm Event Peak Discharge = 10.5 efs 3.0 PROPOSED IMPROVEMENTS 3.1 Proposed Hotel Site Improvements The proposed H2S development includes the removal of the entire existing pavement and structures located on the 1.97 acre 142S site. The proposed construction includes a 12,950 sf footprint 5-level hotel, outdoor swimming pool, and 1 I 1 space concrete parking lot. The proposed development will meet the requirements of the Bryan / College Station Unified Stormwater Design Guidelines by means of a private on -site storm sewer collection system and achieve the required detention through an on -site underground detention system. The post -development flow from the project site will be conveyed via storm conduit into the existing 4'x6' box culvert east of the Applebee's property in TxDOT right-of-way. There were no available studies or plans to determine the design capacity of the 4"x6" box culvert, but based on a rational method analysis and conduit capacity analysis, it has been that the box culvert has adequate capacity to convey the runoff from the 100-year storm event from the H2S site without stormwater detentioning. 3.2 HEC-HMS Proposed Development Basin Model Inlet DA 3 (Vane Drain) 3.2 HEC-HMS Proposed Development Drainage Area Summary 100-Year Storm Event M Global Summary Results for Run "Post 100 @ Clw 5min ti" Project: Home2 Suites Simulation Run: Post 100 0 CI w Smin ti Start of Run: 09302009, 12:00 Basin Model: H25 Post Development End of Run: IOJu12009, 14:30 Meteorologic Model: 24hr - 100 yr Compute Time: 090ct2012, 09:39:56 Control Specifications: Control 1 Volume Units: i , IN ( AC -FT Hydrologic Element Drainage Area (MI2) Peak Discharge (CFS) Time of Peak Volume (IN) Inlet DA 1 .00077149 4.7 10302009, 00:05 10.29 Inlet DA 2 .00080984 4.8 10302009, 00:05 10.93 Inlet DA 3 (... .00070043 3.8 IDJu12009, 00:05 10.77 Roof Downs... .00046452 2.5 10Ju12009, 00:05 11.24 3.3 HEC-HMS 100-Year Storm Event Combined Stormwater Release Rates M Summary Results for Reservoir "Underground Detention" Project: Home2 Suites Simulation Run: Post 100 @ Cl w Smin ti Reservoir: Underground Detention Start of Run: 09302009, 12:00 Basin Model: H25 Post Development End of Run: 103u12009, 14:30 Meteorologic Model: 24hr - 100 yr Compute Time: 09Oct2012, 09:49:19 Control Specifications: Control 1 Volume Units: <a• IN i S AC -FT Computed Results Peak Inflow : 12.1 (CFS) Date/Time of Peak Inflow: 10302009, 00:05 Peak Outflow : 6.5 (CFS) Date/Time of Peak Outflow : 10Jul2009, 00:15 Total inflow : 10.76 (IN) Peak Storage : 0.2 (AC -FT) Total Outflow: 10.75(IN) Peak Elevation: 321.0(FT) 1OSummary Results forJunction"Outfall" I oI 1D £3 Project: Home2 Suites Simulation Run: Post 100 @ CI •w 5min ti ]unction: Outfall Start of Run: 09Jul2009, 12:00 Basin Model: H2S Post Development End of Run: 10102009, 14:30 Meteorologic Model: 24hr - 100 yr Compute Time: 090ct2012, 09:49:19 Control Specifications: Control 1 Volume Units:.p; IN t i AC -FT Computed Results Peak Outflow: 9.9 (CFS) DatelTime of Peak Outflow : 107u12009, 00:10 Total Outflow : 10.76 (IN) i I �I 0' P 40ASSISI I II 1 I r I I I I I I I I I , DRAINAGE EI—s1N—sTM—sTM AREA 1 "— I 138FT I I; 21,508SF '" , It I I� w I 1 I � Q I i ICI [11i I— Q II Q rR II ,. 1 - 'E.,�l_ �� RAIN �� - - PROPERTY INFORMATION: I � I RAIN IGE ..I 11 j • 295 Ft , t x x 1.41 ACRE TRACT, LODGPARK O SECTION ISION LOT 2 NORTH PARK SECTION II I �I� 'H' �i x 0.18 ACRES = LOT 4 -I � DRAINAGE — 19,527 w 0.20 ACRES = LOT 3 AREA ROOF z — �° �F I - o.zo ACRES = LOT 2 _ { SIEVEL `n TOTAL 1.97 ACRES 1zoW sF L 358FT ji1 Ix.-� 3 II _ -, ��— ZONED: Poo I , 300 SOUTH TEXAS AVENUE i{ —� l , COLLEGE STATION, TEXAS 77845 �I .12,9505E OWNER�DEVELOPER: �I• I — f I {{{ VASU DEMLA LLC. 3525 SANDY TRAIL LANE e PLANO, TEXAS 75023 {lo>�..._____�..._.._... i EXHIBIT A OVERALL MAP I� DRAINAGE AREA 2 ® Jr ENGINEERS-PdL'ANNERSS-SURVEYORS 312FT a a { 31,3005EAS NOTED DCR. DAM' AS 0".eY. er: /JOB NO. — � sueNlTrmcoiEo-om xmv. or. y TmR oocuRExt IN RELEASED FOR THE PURPOSE oE: REVIEW a 10/09/2012 UNDER THEAUFxomry OF R I 6iEVEE DUNCPN, P.E. SURL E„fET NO. KRN TODEU EDFDR CONSTRUOTmN,RIDDIM. EX A 8 J PERMRIMGPURPo9ES. | / p..........-�--- / R ��2#! ( gj7 | !!! .�| k } / ■ f §:|| ;}|\ LL. '�GeM�!>«y R# \ \ ; ( DRAINAGE REPORT HOME 2 SUITES HOTEL DEVELOPMENT Prepared for: City of College Station College Station Brazos County, Texas JC Job No.: C0120-001 February 8, 2013 � STEVE E. DUNCAN Prepared by. r�lt g�., 8 3 2 5 2 ; Q 1 JON ES&CARTE R,ixc. ENGINEERS -PLANNERS -SURVEYORS Texas Hoard rfPIf swnal Englrreerm Reglsnntlw Na F-439 1716 Briarcrest Dr., Suite 160 Bryan, TX 77802-2776 979-731-8000 ♦ 979-846-2893 (fax) www,ionescarterm DRAINAGE REPORT HOME 2 SUITES HOTEL DEVELOPMENT FOR CITY OF COLLEGE STATION SCOTT & WHITE LIFT STATION BRAZOS COUNTY, TEXAS JC Job No.: C0120-001 CS File No.: 12-00500217 TABLE OF CONTENTS 1.0 EXECUTIVE SUMMARY.............................................................................................................2 1.1Engineer Contact Information 1.2 Project Site Information 1.3 Watershed Information 1.4 FEMA Information 2.0 EXISTING CONDITIONS..............................................................................................................1 2.1 Location and Topography 2.2 Land Use 2.3 Drainage Patterns 2.4 Existing Conditon HEC-HMS Multi -Year Peak Flow Analysis 3.0 PROPOSED IMPROVEMENTS.....................................................................................................4 3.1 Proposed Hotel Site Improvements 3.2 Proposed Site Drainage Area Data 3.3 Composite Curve Number Calculations 3.3 HEC-HMS Proposed Development Basin Model 3.4 HEC-HMS Input Summary 3.5 Propoed HEC-HMS Multi -Year Storm Event Peak Flow Analysis 3.6 Existing 4'x6' Box Culvert Capacity Analysis 4.0 CONCLUSION...............................................................................................................................6 Exhibit A — Overall Map Exhibit B — Burton Creek Watershed Exhibit C - FEMA Flood Map Table 1 — Time of Concentration Calculation EXHIBITS TABLES 1 1.0 EXECUTIVE SUMMARY 1.1 Engineer Contact Information Steve E. Duncan, P.E. Jones & Carter Inc. 1716 Briarcrest Drive, Suite 160 Bryan, Texas 77802 (979)731-8000 sduncan@jonescarter.com jonescarter.com 1.2 Project Information The Home 2 Suites (H2S) development is located at 300 South Texas Avenue, College Station, Texas, on the following combination of properties totaling 1.97 acres: a. 1.41 Acre tract, Lot 2, Lodgeco Subdivision b. 0.20 Acre tract, Lot 2, North Park Section II c. 0.18 Acre tract, Lot 3, North Park Section II d. 0.18 Acre tract, Lot 4, North Park Section II These four (4) lots form an "L" shaped property with frontage on Texas Avenue and Meadowland. Additionally, the 112S development is located north of the existing Hampton Inn property and south and west of the existing Applebee's and south of a vacant lot located on the northwest corner of the H2S property. Please refer to Exhibit A — Overall Man for additional information. 1.3 Watershed Information The H2S property is located within in the Burton Creek Watershed Area as shown in Exhibit B — Burton Creek Watershed. Per the Bryan/College Station Unified Stormwater Design Guidelines (UDG) dated August 2012, this site is located in a zone that requires additional evaluation to determine the need for stormwater detention. 1.4 FEMA Information The entire property site is situated within the city limits of College Station. According to community panel no. 48041CO21 SE of the Federal Emergency Management Agency's flood insurance rate maps for Brazos County, Texas, effective date May 16, 2012, the subject tract is situated within unshaded zone "X", defined as areas determined to be outside the 500-year flood plain (Exhibit C — FEMA Flood Man). 2.1 Location and Topography (77 QtiJQ 5K'ee The H2S property is located with frontage on two parallel streets, Meadowland Drive to the west and Texas Avenue to the east. The existing 4-plex lots generally slope towards Meadowland Drive with very little topographical relief, resulting in small slopes less than 2%. Additionally, the portion of the subject tract between Meadowland and Texas Avenue can be described as small slopes (less than 2%) towards Texas Avenue with the exception of a steeply sloped 5-foot change in grade with slopes approaching 20% before returning to small slopes (less than 2%) for the remaining 85-feet prior to Texas Avenue. 2.2 Land Use This project consists of four (4) different tracts being combined via a future re -plat into one (1) single 1.97 acre property. The lots remaining from the North Park subdivision currently are fully developed multi -family residential 4-plex units and concrete parking lot. The section of the property remaining from the Lodgeco Subdivision adjacent to Meadowland Drive consists of concrete parking lot for the first 100' towards Texas Avenue, transitioning to overgrown grasses with a few trees in the middle, then the concrete remains of a former building and parking lot for the 80' prior to and adjacent to Texas Avenue. 2.3. Drainage Patterns Three (3) of the existing properties are fully developed 4-plex properties including the 4-plex structure and concrete pavement for parking and access. The runoff from the existing 4-plex properties sheet flows towards Meadowland Drive. These properties include lots 2, 3, and 4 of the North Park Section Il subdivision. The stormwater runoff that enters Meadowland Drive gutter flows south along Meadowland then East along Spence towards Texas Avenue, discharging into Burton Creek Tributary C. Additionally, the remaining 1.41 acre lot 2 of the Lodgeo Subdivision includes a concrete parking lot located along Meadowland Drive between the 4-plex properties and the Hampton Inn property, overgrown grass area, and the remaining pavement from a former development adjacent to Texas Avenue. The stormwater runoff from the 1.41 acre tract sheet flows into Texas Avenue to an inlet and a 4'x6' box culvert located east of the Applebee's property north of the subject tract. The 4'x6' box culvert then conveys the stormwater to Burton Creek Tributary C.3. 2.4 Existing Condition AEC -HMS Multi -Year Peak Flow Analysis Storm Event Peak Flow ds 2 3.90 10 6.80 25 8.10 50 9.60 100 10.50 3.0 PROPOSED IMPROVEMENTS 3.1 Proposed Hotel Site Improvements The proposed H2S development includes the removal of the entire existing pavement and structures located on the 1.97 acre H2S site. The proposed construction includes a 12,950 sf footprint 5-level hotel, outdoor swimming pool, and 111 space concrete parking lot. The proposed development will meet the requirements of the Bryan / College Station Unified Stormwater Design Guidelines by means of a private on -site stonn sewer collection system and underground detention pond, resulting in reduced post -development runoff from pre -developed. The post -development flow from the project site will be conveyed via 24-inch storm conduit into the existing 4'x6' box culvert east of the Applebee's property in TxDOT right-of-way. 3.2 Proposed Site Drainage Area Data 11) 12) 13) 14) m en Area Hydraulic Land Use v length ° 4 Z Developed Grass (sq. Wooded a ft2 Acre mi (ft.) (sq. ft.) ft.) (sq. ft.) DA-1 21,508.0 0.49376 0.0007715 540.00 17,764.00 3,744.00 - DA-2 31,439.0 0.72174 0.0011277 312.00 26,068.00 5,371.00 - DA-3 19,527.0 0.44828 0.00070041 295.00 13,173.00 6,354.00 - DA-4 12,950.0 0.29729 0.0004645 1 358.00 12,950.00 1 - I- Notes: (1) Refer to Exhibit A- Drainage Area Map for Drainage Area location. (2) Square footages were taken from CAD drawings. (3) Slope and velocities of various flow lines were compared in order to determine the most hydraulically remote point. (4) Land use was based on Chart C-3 from the BCS Unified Stormwater Design Guidelines. Ell 3.2 Composite Curve Number Calculations 0) (2) (3) (4) (2) (3) (4) (2) l3) (5) 16) M Pasture -Fair Soil Group C Woods -Good Soil Group C Developed Soil Group C HMS input Drainage Area Area CN %Imp Area CN %Imp Area CN %Imp Total % Impervious Weighted g CN Acres Acres Acres DA 1 3,744.00 79 0 - 76 0 17,764.00 94 85 70.20 70.48 57.34 85.00 91.39 91.44 89.12 94.00 DA 2 5,371.00 79 0 - 76 0 26,068.00 94 85 DA3 6,354.00 79 0 - 76 0 13,173.00 94 85 DA 4 - 79 0 1 - 76 0 12,950.00 94 85 Notes: (1) Refer to Exhibit A- Drainage Area Map for Drainage Area location. (2) Area in acres were taken from CAD drawings. (3) Curve numbers based on the B/CS Stonnwater Design Guidelines, Table C-7 Curve Numbers (SCS). (4) Percent impervious does not apply to undeveloped pastures or wooded areas. (5) Percent impervious is based on B/CS Stonnwater Design Guidelines, Table C-7 Percent hnnervious Area. (6) Total Percent hpervious; [Al x %I, + A2 s %12 + A3 x %I3] / ATOTAr (7) Weighted CN = [CNI x A, + CN2 x A2 + CN3 x A3] / ATOTAL 3.3 HEC-HMS Proposed Development Basin Model Inlet DA 2 1,$." Inlet DA 4 Downspouts DA1 DA 3 (Vane Drain) Pond Junction Underground Detention Outfall 6i Exhibit A —Overall Map Exhibit B — Burton Creek Watershed Exhibit B - Burton Creek Watershed SECTION IX APPENDIX B — REGION'S WATERSHEDS I I I I IFeet 0 1500 3b00 7200 Figure B-6: Burton Creek Watershed Area STORMWATER DESIGN GUIDELINES Page 9 of 24 APPENDIX B: REGION'S WATERSHEDS Effective February 2007 As Revised August 2012 Exhibit C — FEMA Flood Map U E c c F` u u U C ?° TABLES Home 2 Suites - Drainage Report Time of Concentration Calculations Drainage Area 1 Total Flow Length ................................................. 540 Total Shallow Concentrated Flow Length .......... 0 Total Channel Flow Length ................................... 402 Sheet Flow.(aoolicable to Tc oniv) 1 Segment ID 2 Surface Description (table 3-1) ............................ 3 Manning's Roughness Coefficient, n (table 3-1) 4 Flow Length, L (total L < 300 ft) ............................. 5 Two-year 24-hour rainfall, P2 (BCS Table C-6)... 6 Land Slope, s............................................................ 7 Tt = (0.007*(nL)")/(P2 0 .5s 0.4) ............ DA 1 Paved 0.011 ft 138 in 4.5 ft/ft 0.0177 hr 0.0231 Shallow Concentrated Flow 8 Segment ID DA 1- none 9 Surface Description 0 10 Flow Length, L........................................................... ft 0 11 Watercourse Slope, s............................................... ft/ft 0 12 Average Velocity, V (figure 3-1) ............................. ft/s 0 13 Tt=(L/3600*V)........................................................... hr 0 I Channel Flow 14 Segment ID 24" PVC 15 Cross Section Flow Area, a .................................... 16 Wetted Perimeter, pw.............................................. 16 Hydraulic Radius, r=a/pw......................................... 17 Channel slope, s...................................................... 18 Manning's Roughness Coefficient, n ................... 19 V=(1.49r2/3s1/2)/n.................................................... 20 Flow Length, L.......................................... 21 Tt=(L/3600*V).......................................... ft2 ft 3.14159 6.283188 ft 0.5 ft/ft 0.005 0.011 —� ft/s 6.03 ft 402 hr 0.0185 Drainage Area Tc hr 1 0.0416 Drainage Area TL hr 1 0.0250 Page 1 of 4 Home 2 Suites - Drainage Report Time of Concentration Calculations Drainage Area 2 Total Flow Length ................................................. Total Shallow Concentrated Flow Length .......... Total Channel Flow Length ................................... Sheet Flow (applicable to Tc only) 1 Segment ID 2 Surface Description (table 3-1) ............................ 3 Manning's Roughness Coefficient, n (table 3-1) 4 Flow Length, L (total L < 300 ft) ............................. 5 Two-year 24-hour rainfall, P2 (BCS Table C-6)... 6 Land Slope, s............................................................ 7 Tt = (0.007*(nL)")/(P2O.ss .4) ............ IShallow,Concentrated Flow 8 Segment ID 9 Surface Description 10 Flow Length, L........................................................... 11 Watercourse Slope, s............................................... 12 Average Velocity, V (figure 3-1) ............................. 13 Tt=(L/3600*V)........................................................... (Channel Flow 14 Segment ID 15 Cross Section Flow Area, a ..................................... 16 Wetted Perimeter, pw.............................................. 16 Hydraulic Radius, r=a/pw......................................... 17 Channel slope, s....................................................... 18 Manning's Roughness Coefficient, n ..................... 19 V=(1.49r2/3s1/2)/n .................................................... 20 Flow Length, L........................................................... 21 Tt=(L/3600*V)........................................................... 312 0 0 DA 1 Paved 0.011 -� ft 312 in 4.5 ft/ft 0.0149 hr 0.0476 I DA 1 none I 0� ft 0 ft/ft 0 —� ft/s 0 hr 0 one ft2 0 ft I 0 — ft 0� ft/ft 0 0 ft/s 0.00 ft 0 hr 0.0000 Drainage Area Tc hr 1 0.0476 Drainage AreaTL hr 1 0.0286 Page 2 of 4 Home 2 Suites - Drainage Report Time of Concentration Calculations Drainage Area 3 Total Flow Length ................................................. 295 Total Shallow Concentrated Flow Length .......... 0 Total Channel Flow Length ................................... 0 Sheet Flow (applicable to Tc only) 1 Segment ID 2 Surface Description (table 3-1) ............................ 3 Manning's Roughness Coefficient, n (table 3-1) 4 Flow Length, L (total L < 300 ft) ............................. 5 Two-year 24-hour rainfall, P2 (BCS Table C-6)... 6 Land Slope, s............................................................ 7 Tt = (0.007*(nL)0.$)/(Pz .ss .4) ............ DA 1 Paved —� �0.011 ft 1295 in 4.5 —� ft/ft —0.005 hr 0.0704 Shallow Concentrated Flow 8 Segment ID DA 1 - none 9 Surface Description t�— 00 — 10 Flow Length, L........................................................... ft I 0 11 Watercourse Slope, s............................................... ft/ft-0 12 Average Velocity, V (figure 3-1) ............................. ft/s 0 13 Tt=(L/3600*V)........................................................... hr �— 0 Channel Flow 14 Segment ID L none 15 Cross Section Flow Area, a ..................................... ft2 0�� 16 Wetted Perimeter, pw.............................................. ft 0 16 Hydraulic Radius, r=a/pw......................................... ft 0 17 Channel slope, s....................................................... ft/ft 0 --� 18 Manning's Roughness Coefficient, n ..................... —0� 19 V=(1.49r2/3s1/2)/n ft/s 0.000 20 Flow Length, L........................................................... ft (� I 0 21 Tt=(L/3600*V)........................................................... hr 0.0000 Drainage AreaTc hr 1 0.0704 Drainage Area TL hr 1 0.0423 Page 3 of 4 Home 2 Suites - Drainage Report Time of Concentration Calculations Drainage Area 4 Total Flow Length ................................................. Total Shallow Concentrated Flow Length .......... Total Channel Flow Length ................................... Sheet Flow (applicable to Tconly) 1 Segment ID 2 Surface Description (table 3-1) ............................ 3 Manning's Roughness Coefficient, n (table 3-1) 4 Flow Length, L (total L < 300 ft) ............................. 5 Two-year 24-hour rainfall, P2 (BCS Table C-6)... 6 Land Slope, s............................................................ 7 Tt = (0.007*(nL)0.8)/(P2 0 .55 .4) ............ 358 0 358 DA 1 L none �— 0 ft 0 in4.5 ft/ft 0 hr 0.0000 Shallow Concentrated' Flow 8 Segment ID DA 1 - none 9 Surface Description 0 10 Flow Length, L........................................................... ft �� I 0 11 Watercourse Slope, s................... I........................... ft/ft 1 0 -� 12 Average Velocity, V (figure 3-1) ............................. ft/s L 0 13 Tt=(L/3600*V)........................................................... hr 1 v Channel Flow 14 Segment ID 15 Cross Section Flow Area, a ..................................... 16 Wetted Perimeter, pw.............................................. 16 Hydraulic Radius, r=a/pw......................................... 17 Channel slope, s....................................................... 18 Manning's Roughness Coefficient, n ..................... 19 V=(1.49r2/3s1/2)/n .................................................... 20 Flow Length, L........................................................... 21 Tt=(L/3600*V)........................................................... — L 18" PVC ft2 L 1.767144375 ft 4.712385 ft 0.375 ft/ft 0.005 0.011 ft/s 4.98 ft 358 hr 0.0200 Drainage Area Tc hr 0.0200 Drainage Area TL hr 0.0120 Page 4 of 4 SECTION IX APPENDIX D - TECHNICAL DESIGN SUMMARY Part 2 — Project Administration Start (Page 2.1) Engineering and Design Professionals Information Engineering Firm Name and Address: Jurisdiction Jones & Carter, Inc. City: Bryan 1716 Briarerest Drive, Suite 160 x College Station Bryan, Texas 77802 Date of Submittal: Lead Engineer's Name and Contact Info.(phone, e-mail, fax Other: Steve E. Duncan, P.E. sduncan@jonescarter.com (979) 731-8000 (office) (979) 846-2893 (fax) Supporting Engineering / Consulting Firm(s): Other contacts: N/A N/A Developer / Owner / Applicant Information` Developer / Applicant Name and Address: Phone and e-mail: Vasu Demla- LLC surajdemla@yahoo.com Suraj Demla (214) 284-6492 3525 Sandy Trail Lane Plano Texas 75023 Property Owner(s) if not Developer / Applicant (& address): Phone and e-mail: Project Identification Development Name: Home2 Suites Hotel Is subject property a site project, a single-phase subdivision, or part of a multi -phase subdivision? Site If multi -phase, subject property is phase of Legal description of subject property (phase) or Project Area: (see Section II, Paragraph B-3a) 1.41 acre tract, Lodgeco Subdivision lot 2 0.18 acre tract, North Park Section II, Lot 2 0.18 acre tract, North Park Section II, Lot 3 0.20 acre tract, North Park Seciton II, Lot 4 If subject property (phase) is second or later phase of a project, describe general status of all earlier phases. For most recent earlier phase Include submittal and review dates. NA General Location of Project Area, or subject property (phase): Located on Texas Avenue, North of University Drive and south of the College Station city limits. In City Limits? Extraterritorial Jurisdiction (acreage): Bryan: acres. Bryan: College Station: College Station: 1.97 acres. Acreage Outside ETJ: STORMWATER DESIGN GUIDELINES Page 3 of 26 APPENDIX. D: TECH. DESIGN SUMMARY Effective February 2007 As Revised Auoust 2012 SECTION IX APPENDIX D - TECHNICAL DESIGN SUMMARY Part 2 — Project Administration Continued (page 2.2) Project Identification (continued) Roadways abutting or within Project Area or Abutting tracts, platted land, or built subject property: developments: Texas Avenue to the Bast Hampton Inn to the south Applebees to the north Meadowland St to the West Vacant lot, part of Northpoint Crossing Subdivision to northwest Named Regulatory Watercourse(s) & Watershed(s): Tributary Basin(s): Burton Creek Watershed Plat Information For Project or Subject Property (or Phase) Preliminary Plat File #: Final Plat File #: Date: Name: Status and Vol/Pg: Final plat is in progress If two plats, second name: File #: Status: Date: Zoning Information For Project or Subject Property (or Phase) Zoning Type: pdd Existin r Proposed? Case Code: Case Date Status: Zoning Type: Existing or Proposed? Case Code: Case Date Status: Stormwater Management Planning For Project or Subject Property (or Phase) Planning Conference(s) & Date(s): Participants: 08/17/2011 Jason Schubert Lauren Hovde Raymond Olson Gilbert Martinez Joe Guerra Preliminary Report Required? NA Submittal Date Review Date Review Comments Addressed? Yes _ No _ In Writing? When? Compliance With Preliminary Drainage Report. Briefly describe (or attach documentation explaining) any deviation(s) from provisions of Preliminary Drainage Report, if any. NA STORMWATER DESIGN GUIDELINES Page 4 of 26 APPENDIX. D: TECH. DESIGN SUMMARY Effective February 2007 As Revised August 2012 SECTION IX APPENDIX D - TECHNICAL DESIGN SUMMARY Part 2 — Project Administration Continued (page 2.3) Coordination For Project or Subject Property (or Phase) Note: For any Coordination of stormwater matters indicated below, attach documentation describing and substantiating any agreements, understandings, contracts, or approvals. Dept. Contact: Date: Subject: Coordination NA With Other Departments of Jurisdiction City (Bryan or College Station) Coordination With Summarize need(s) & actions taken (include contacts & dates): Non jurisdiction City Needed? Yes _ No x Coordination with Summarize need(s) & actions taken (include contacts & dates): Brazos County Needed? Yes _ No x Summarize need(s) & actions taken (include contacts & dates): Coordination with Tie into curb inlet located in TxDOT ROW. TxDOT per nit has been submitted through TxDOT Needed? City of College Station. Yes x No _ Summarize need(s) & actions taken (include contacts & dates): Coordination with TAMUS Needed? Yes No x Permits For Project or Subject Property (or Phase) —of As to stormwater management, are permits required for the proposed work from my the entities listed below? If so, summarize status of efforts toward that objective ins aces below. EntityPermitted or Status of Actions (include dates) Approved ? US Army Crops of Engineers No x Yes _ US Environmental Protection Agency No x Yes Texas Commission on Environmental Quality No x Yes Brazos River Authority No x Yes STORMWATER DESIGN GUIDELINES Page 5 of 26 APPENDIX. D: TECH. DESIGN SUMMARY Effective February 2007 As Revised August 2012 SECTION IX APPENDIX D - TECHNICAL DESIGN SUMMARY Part 3 — Property Characteristics Start (Page 3.1) Nature and Scope of Proposed Work Existina: Land proposed for development currently used, including extent of impervious cover? Site contains 3 existing 4-plex with concrete parking and access drive, ashpalt overflow parking for the former Plaza hotel development, and various pavement along Texas Avenue from previous developments. 0.81 acres of existing impervious surfaces, x Redevelopment of one platted lot, or two or more adjoining Platted lots. la la Site Development Building on a single platted lot of undeveloped land. Project Building on two or more platted adjoining lots of undeveloped land. (select all Building on a single lot, or adjoining lots, where proposed plat will not form applicable) a new street (but may include ROW dedication to existing streets). Other (explain): Subdivision Construction of streets and utilities to serve one or more platted lots. Development Construction of streets and utilities to serve one or more proposed lots on Project _ lands represented by pending plats. Site proiects: building use(s), approximate floor space, impervious cover ratio. Subdivisions: number of lots by general type of use, linear feet of streets and Describe Natand Nature re drainage easements or ROW. Proposed 60,000 sf (5-level) hotel with swimming pool and 110 space parking lot. 1.59 acres of Size ofproposed impervious. Proposed Project Is any work planned on land that is not platted If yes, explain: or on land for which platting is not pending? x No Yes FEMA Floodplains Is any part of subject property abutting a Named Regulatory Watercourse No x Yes (Section II, Paragraph B1) or a tributary thereof? Is any part of subject property in floodplain No x Yes Rate Map area of a FEMA-regulated watercourse? Encroachment(s) Encroachment purpose(s): Building site(s) Road crossing(s) into Floodplain areas planned? Utility crossing(s) —Other (explain): No Yes If floodplain areas not shown on Rate Maps, has work been done toward amending the FEMA- approved Flood Study to define allowable encroachments in proposed areas? Explain. STORMWATER DESIGN GUIDELINES Page 6 of 26 APPENDIX. D: TECH. DESIGN SUMMARY Effective February 2007 As Revised August 2012 SECTION IX APPENDIX D - TECHNICAL DESIGN SUMMARY Part 3 —Property Characteristics Continued (Page 3.2) Hydrologic Attributes of Subject Property (or Phase) Has an earlier hydrologic analysis been done for larger area including subject property? Reference the study (& date) here, and attach copy if not already in City files. Yes Is the stormwater management plan for the property in substantial conformance with the earlier study? Yes No If not, explain how it differs. If subject property is not part of multi -phase project, describe stormwater management No plan for the property In Part 4. rise of underground detention system If property is part of multi -phase project, provide overview of stormwater management plan for Project Area here. In Part 4 describe how plan for subject property will comply therewith. NA Do existing topographic features on subject property store or detain runoff? x No Yes Describe them (include approximate size, volume, outfall, model, etc). Any known drainage or flooding problems in areas near subject property? x No Yes Identify: Based on location of study property in a watershed, is Type 1 Detention (flood control) needed? (see Table B-1 in Appendix B) Detention is required. x Need must be evaluated. _ Detention not required. What decision has been reached? By whom? Detention is required. Per Erika Bridges If the need for How was determination made? Type 1 Detention NA must be evaluated: STORMWATER DESIGN GUIDELINES Page 7 of 26 APPENDIX, D: TECH. DESIGN SUMMARY Effective February 2007 As Revised August 2012 SECTION IX APPENDIX D - TECHNICAL DESIGN SUMMARY Part 3 —Property Characteristics Continued (Page 3.3) Hydrologic Attributes of Subject Property (or Phase) (continued) Does subject property straddle a Watershed or Basin divide? x No _ Yes If yes, describesplits below. In Part 4 describe design conce t for an in this. Watershed or Basin Larger acreage Lesser acreage Above -Project Areas(Section ll, Paragraph B3-a) Does Project Area (project or phase) receive runoff from upland areas? x No —Yes Size(s) of area(s) in acres: 1) 2) 3) 4) Flow Characteristics (each instance) (overland sheet, shallow concentrated, recognizable concentrated section(s), small creek (non -regulatory), regulatory Watercourse or tributary); Flow determination: Outline hydrologic methods and assumptions: Does storm runoff drain from public easements or ROW onto or across subject property? No _ Yes If yes, describe facilities in easement or ROW: Are changes in runoff characteristics subject to change in future? Explain Conveyance Pathways (Section II, Paragraph C2) Must runoff from study property drain across lower properties before reaching a Regulatory Watercourse or tributary? No x Yes Describe length and characteristics of each conveyance pathway(s). Include ownership of property(ies). The runoff will be conveyed approximately 80' by an existing TxDOT culvert crossing Texas Avenue. Then the underground TxDOT box culvert continues for approximately 2001f further before daylighting into Burton Creek Tributary C.3. STORMWATER DESIGN GUIDELINES Page 8 of 26 APPENDIX. D: TECH. DESIGN SUMMARY Effective February 2007 As Revised August 2012 SECTION IX APPENDIX D - TECHNICAL DESIGN SUMMARY Part 3 — Property Characteristics Continued (Page 3.4) Hydrologic Attributes of Subject Property (or Phase)(continued) Conveyance Pathways (continued) Do drainage If yes, for what part of length? % Created by? _ plat, or easements instrument. If instrument(s), describe their provisions. exist for any part of NA pathway(s)? x No Yes Where runoff must cross lower properties, describe characteristics of abutting lower property(ies). (Existing watercourses? Easement or Consent aquired?) Pathway NA -- the lower property is Texas Areas Avenue. Describe any built or improved drainage facilities existing near the property (culverts, bridges, lined channels, buried conduit, swales, detention ponds, etc). Curb Inlet 100' downstream on subject properties side of Texas Avenue, subsequent Box Culvert crossing Texas Avene and extending under the Fairfield Inn parking lot before discharging into Burton Creek Tributary C3 Nearby Drainage Do any of these have hydrologic or hydraulic influence on proposed stormwater Facilities design? No x Yes If yes, explain: Yes, the existing storm conveyance facilities currently conveys the stormwater flow from the subject tract. There are no know issues existing with the stormwater conveyance through these facilities. The exismig 4' x 6' box culvert was constructed with additional capacity which is currently unused. STORMWATER DESIGN GUIDELINES Page 9 of 26 APPENDIX. D: TECH. DESIGN SUMMARY Effective February 2007 As Revised August 2012 SECTION IX APPENDIX D - TECHNICAL DESIGN SUMMARY Part 4 — Drainage Concept and Design Parameters Start (Page 4.1) Stormwater Management Concept Discharge(s) From Upland Area(s) If runoff is to be received from upland areas, what design drainage features will be used to accommodate it and insure it is not blocked by future development? Describe for each area, flow section, or discharge point. NA Discharge(s) To Lower Property(ies) (Section II, Paragraph E1) Does project include drainage features (existing or future) proposed to become public via platting? x No Yes Separate Instrument? x No Yes Per Guidelines reference above, how will Establishing Easements (Scenario 1) runoff be discharged to neighboring x Pre -development Release (Scenario 2) property(ies)? Combination of the two Scenarios Scenario 1: If easements are proposed, describe where needed, and provide status of actions on each. (Attached Exhibit # ) NA Scenario 2: Provide general description of how release(s) will be managed to pre -development conditions (detention, sheet flow, partially concentrated, etc.). (Attached Exhibit # ) Stormwater releases to lower properties will be managed via an underground detention pond. Please refer to Drainage report for additional information. Combination: If combination is proposed, explain how discharge will differ from pre - development conditions at the property line for each area (or point) of release. NA If Scenario 2, or Combination are to be used, has proposed design been coordinated with owner(s) of receiving property(ies)? No x Yes Explain and provide documentation. Communictation with Jay Page with TxDOT. They are comfortable taking 100% of the post development flow through their facilities as long as their existing facilities have capacity. Capacity analysis is attached. We are only proposing to release the predevelopment flows from our property. STORMWATER DESIGN GUIDELINES Page 10 of 26 APPENDIX. D: TECH. DESIGN SUMMARY Effective February 2007 As Revised August 2012 SECTION IX APPENDIX D - TECHNICAL DESIGN SUMMARY Part 4 — Drainage Concept and Design Parameters Continued (Page 4.2) Stormwater Management Concept(continued) Within Project Area Of Multi -Phase Project Identify gaining Basins or Watersheds and acres shifting: Will project result NA in shifting runoff between Basins or What design and mitigation is used to compensate for increased runoff between Watersheds? from gaining basin or watershed? x No NA Yes How will runoff from Project 1. — With facility(ies) involving other development projects. Area be mitigated to pre- 2 Establishing features to serve overall Project Area. development conditions? Select any or all of 1, 2, 3. On phase (or site) project basis within Project Area. and/or 3, and explain below. 1. Shared facility (type & location of facility; design drainage area served; relationship to size of Project Area): (Attached Exhibit # ) 2. For Overall Project Area (type & location of facilities): (Attached Exhibit # ) 3. By phase (or site) proiect: Describe planned mitigation measures for phases (or sites) in subsequent questions of this Part. Are aquatic echosystems proposed? No Yes In which phase(s) or project(s)? a >- Are other Best Management Practices for reducing stormwater pollutants proposed? IL No Yes Summarize type of BMP and extent of use: N C m 0 N O 0 Z ca If design of any runoff -handling facilities deviate from provisions of B-CS Technical (D Specifications, check type facility(ies) and explain in later questions. U) m Detention elements Conduit elements Channel features — Swales Ditches Inlets Valley gutters _ Outfalls Culvert features Bridges Other STORMWATER DESIGN GUIDELINES Page 11 of 26 APPENDIX. D: TECH. DESIGN SUMMARY Effective February 2007 As Revised August 2012 SECTION IX APPENDIX D - TECHNICAL DESIGN SUMMARY Part 4 — Drainage Concept and Design Parameters Continued (Page 4.3) Stormwater Management Concept ,(continued) Within Project Area Of Multi -Phase Project (continued) Will Project Area include bridge(s) or culvert(s)? No _Yes Identify type and general size and In which phase(s). NA If detention/retention serves (will serve) overall Project Area, describe how it relates to subject phase or site project (physical location, conveyance pathway(s), construction sequence): NA Within Or Serving Subject Property (Phase, or Site) If property part of larger Project Area, is design in substantial conformance with earlier analysis and report for larger area? Yes R No, then summarize the difference(s): Identify whether each of the types of drainage features listed below are included, extent of use, and general characteristics. Typical shape? Surfaces? Steepest side slopes: Usual front slopes: Usual back slopes: N Flow line slopes: least Typical distance from travelway: (Attached Exhibit # ) typical greatest O N Z co 0 x Are longitudinal culvert ends in compliance with B-CS Standard Specifications? T Yes No, then explain: At intersections or otherwise, do valley gutters cross arterial or collector streets? m W No Yes If yes explain: U r y N� Are valley gutters proposed to cross any street away from an intersection? m0 No Explain: (number of locations?) w� _ _Yes � Mx ¢ STORMWATER DESIGN GUIDELINES Page 12 of 26 APPENDIX. D: TECH. DESIGN SUMMARY Effective February 2007 As Revised August 2012 SECTION IX APPENDIX D - TECHNICAL DESIGN SUMMARY Part 4 Drainage Concept and Continued (Page 4.4) Stormwater Macontinued) =Site) Within Or Serving Subject Property (Ped) Gutter line slopes: Least Greatest NA Are inlets recessed on arterial and collector streets? — Yes — No If "no", identify where and why. Will inlets capture 10-year design stormflow to prevent flooding of intersections (arterial with arterial or collector)? — Yes — No If no, explain where and why not. r. a 0 Will inlet size and placement prevent exceeding allowable water spread for 10-year a) design storm throughout site (or phase)? Yes — No If no, explain. m na) Sag curves: Are inlets placed at low points? _ Yes _ No Are inlets and conduit sized to prevent 100-year stormflow from pending at greater than 24 inches? Yes No Explain "no" answers. o — ,3 a� a� B Will 100-yr stormflow be contained in combination of ROW and buried conduit on Q whole length of all streets? —Yes — No If no, describe where and why. Do designs for curb, gutter, and inlets comply with B-CS Technical Specifications? Yes No If not, describe difference(s) and attach justification. Are any 12-inch laterals used? x No —Yes Identify length(s) and where used. C1. Pipe runs between system Typical 120 & snorter Longest 265LF M access points (feet): r aa) Are junction boxes used at each bend? x Yes No If not, explain where x N I and why. G O @Z a E ° Are downstream soffits at or below upstream soffits? Least amount that hydraulic N Yes x No If not, explain where and why: grade line is below gutter line — (system -wide): 4.5' STORMWATER DESIGN GUIDELINES Page 13 of 26 APPENDIX. D: TECH,As ReviseGN d AugustSUMMARY Effective February 2007 SECTION IX APPENDIX D - TECHNICAL DESIGN SUMMARY Part 4 — Drainage Concept and Design Parameters Continued (Page 4.5) Stormwater Management Concept (continued) Within Or Serving Subject Property (Phase, or Site) (continued) Describe watercourse(s), or system(s) receiving system discharge(s) below (include design discharge velocity, and angle between converging flow lines). m 1) Watercourse (or system), velocity, and angle? N PVC Storm Conduit, 5.17ft/s, 0.5% c d a) E 2) Watercourse (or system), velocity, and angle? � o c d U � aa) E v 3) Watercourse (or system), velocity, and angle? CO O 0 0 `o 0 ;_ For each outtall above, what measures are taken to prevent erosion or scour of o (D receiving and all facilities at juncture? 1) These outfall into underground detention pond. Ultimately outfalling into TxDOT storm n. m 2) 0 3) Are swale(s) situated along property lines between properties? No q Yes Number of instances: l For each instance answer the following questions. Surface treatments (including low -flow flumes if any): Entire channel is a gravel lined. at 6 } Flow line slopes (minimum and maximum): Average slope 0.7% 0 Wz Outfall characteristics for each (velocity, convergent angle, & end treatment). co <3 ft/s. Outfalls into a storm junction box which conveys to detention pond. 3 I m Q Will 100-year design storm runoff be contained within easement(s) or platted drainage ROW in all instances? x Yes No If "no" explain: STORMWATER DESIGN GUIDELINES Page 14 of 26 APPENDIX. D: TECH, DESIGN SUMMARY Effective February 2007 As Revised August2012 SECTION IX APPENDIX D - TECHNICAL DESIGN SUMMARY Part 4 — Drainage Concept and Design Parameters Continued (Page 4.6) Stormwater Management Concept (continued) Within Or Serving Subject Property (Phase, or Site) (continued) Are roadside ditches used? x No Yes If so, provide the following: W Is 25-year flow contained with 6 inches of freeboard throughout? —Yes —No Are top of banks separated from road shoulders 2 feet or more? Yes — No o — Are all ditch sections trapezoidal and at least 1.5 feet deep? Yes No N For any "no" answers provide location(s) and explain: a m 0 If conduit is beneath a swale, provide the following information (each instance). Instance 1 Describe general location, approximate length: N r Is 100-year design flow contained in conduit/swale combination? —Yes —No If "no" explain: N U o Space for 100-year storm flow? ROW Easement Width z c Swale Surface type, minimum Conduit Type and size, minimum and maximum x m and maximum slopes: slopes, design storm: c 0 u a � @ Inlets Describe how conduit is loaded (from streets/storm drains, inlets by type): C T c C L � U 0 C c- o Access Describe how maintenance access is provided (to swale, into conduit): o r, o f6 E o Instance 2 Describe general location, approximate length: E N as a Is 100-year design flow contained in conduit/swale combination? —Yes No ° o If "no" explain: m a c E aa) Space for 100-year storm flow? ROW Easement Width o U Swale Surface type, minimum Conduit Type and size, minimum and maximum '5 mand 2 maximum slopes: slopes, design storm: m Inlets Describe how conduit is loaded (from streets/storm drains, inlets by type): 0 @ c 0 3 Access Describe how maintenance access is provided (to swale, into conduit): Q STORMWATER DESIGN GUIDELINES Page 15 of 26 APPENDIX. D: TECH. DESIGN SUMMARY Effective February 2007 As Revised August 2012 SECTION IX APPENDIX D — TECHNICAL DESIGN SUMMARY Part 4 —Drainage Concept and Design Parameters Continued (Page 4.7) Stormwater Management Concept (continued) Within Or Serving Subject Property (Phase, or Site) (continued) If "yes' provide the following information for each instance: Instance 1 Describe general location, approximate length, surfacing: G 0 O w tS ui Is 100-year design flow contained in swale? _ Yes No Is Swale wholly within drainage ROW? Yes No Explainno" answers: a) Access Describe how maintenance access is provide: O Z X O 0 Instance 2 Describe general location, approximate length, surfacing: ,a d .L h. 0 m o E L a) 3 ca Is 100-year design flow contained in swale? _ Yes _ No Is swale wholly within drainage ROW? Yes No Explain "no" answers: 0 N0 � Access Describe how maintenance access is provided: 7j U_ Q 7 0. Instance 3. 4, etc. If swales are used in more than two instances, attach sheet providing all above information for each instance. "New" channels: Will any area(s) of concentrated flow be channelized (deepened, widened, or straightened) or otherwise altered? x No Yes If only slightly shaped, see "Swales" in this Part. If creating side banks, provide information below. Will design replicate natural channel? Yes _ No If "no", for each instance o Q _ describe section shape & area, flow line slope (min. & max.), surfaces, and 100-year o 'uf design flow, and amount of freeboard: ° Instance 1: NA c � 0 E a) o Instance 2: `0 E O Z 0 X Instance 3: as U STORMWATER DESIGN GUIDELINES Page 16 of 26 APPENDIX. D: TECH. DESIGN SUMMARY Effective February 2007 As Revised August 2012 SECTION IX APPENDIX D - TECHNICAL DESIGN SUMMARY Part 4 — Drainage Concept and Design Parameters Continued (Page 4.8) Stormwater Management Concept (continued) Within Or Serving Subject Property (Phase, or Site) (continued) Existing channels (small creeks): Are these used? x No _Yes If "yes" provide the information below. Will small creeks and their floodplains remain undisturbed? _d Yes _ No How l many disturbance instances? Identify each planneocation: For each location, describe length and general type of proposed improvement (including floodplain changes): For each location, describe section shape & area, flow line slope (min. & max.), surfaces, and 100-year design flow. W m c c Watercourses (and tributaries): Aside from fringe changes, are Regulatory 0 Watercourses proposed to be altered? x No Yes Explain below. c Submit full report describing proposed changes to Regulatory Watercourses. Address E existing and proposed section size and shape, surfaces, alignment, flow line changes, length affected, and capacity, and provide full documentation of analysis procedures o and data. Is full report submitted? Yes No If "no" explain: E m c c L All Proposed Channel Work: For all proposed channel work, provide information v requested in next three boxes. If design is to replicate natural channel, identify location and length here, and describe design in Special Design section of this Part of Report. NA Will 100-year flow be contained with one foot of freeboard? _ Yes _ No If not, identify location and explain: NA Are ROW / easements sized to contain channel and required maintenance space? _ Yes _ No If not, identify location(s) and explain: NA STORMWATER DESIGN GUIDELINES Page 17 of 26 APPENDIX. D: TECH. DESIGN SUMMARY Effective February 2007 As Revised August 2012 SECTION IX APPENDIX D — TECHNICAL DESIGN SUMMARY Part 4 — Drainage Concept and Design Parameters Continued (Page 4.9) Stormwater Management Concept (continued) Within Or Serving Subject Property (Phase, or Site) (continued) How many facilities for subject property project? I For each provide info. below. For each dry -type facilitiy: Facility 1 Facility 2 Acres served & design volume + 10% 0-215 acre-£t 100-yr volume: free flow & plugged 0.1955 acre-ft Design discharge (10 yr & 25 yr) 4.4efs 5.5cfs Spillway crest at 100-yr WSE? x yes no yes no Berms 6 inches above plugged WSE? 1 x yes no yes _ no Explain any "no" answers: Underground Detention Pond is designed to not be likely to be plugged, w at } x For each facility what is 25-yr design Q, and design of outlet structure? Facility 1: 14.2 cfs, Outlet Structure: Box with 035sf opening at bottom and 0.6sf opening; refer to o construction documents and report. Z Facility 2: Do outlets and spillways discharge into a public facility in easement or ROW? Facility 1: x Yes No Facility 2: _ Yes No '0 _ If "no" explain: ro 0 0 0 0 oN For each, what is velocity of 25-yr design discharge at outlet? & at s iIP Tway? 2' Facility 1: 3.3zft/s & s.sc£s Facility 2: & 5 Are energy dissipation measures used? t No _ Yes Describe type and co rL location: C 0 0 0 B For each, is spillway surface treatment other than concrete? Yes or no, and describe: Q Facility 1: Spillway is combined in concrete junction box and discharges into 30" PVC conduit Facility 2: For each, what measures are taken to prevent erosion or scour at receiving facility? Facility 1: None are necessary Facility 2: If berms are used give heights, slopes and surface treatments of sides. Facility 1: NA Facility 2: STORMWATER DESIGN GUIDELINES Page 18 of 26 APPENDIX. D: TECH. DESIGN SUMMARY Effective February 2007 As Revised August 2012 SECTION IX APPENDIX D - TECHNICAL DESIGN SUMMARY Part 4 — Drainage Concept and Design Parameters Continued (Page 4.10) Stormwater Management Concept (continued) Within Or Serving Subject Property (Phase, or Site) (continued) Do structures comply with B-CS Specifications? Yes or no, and explain if "no": Facility 1; Yes m LL °�� Facility 2: G '- O C 'C O U' N oFor additional facilities provide all same information on a separate sheet. Are parking areas to be used for detention? X No Yes What is maximum depth due to required design storm? Roadside Ditches: Will culverts serve access driveways at roadside ditches? X No _ Yes If "yes", provide information in next two boxes. Will 25-yr. flow pass without flowing over driveway in all cases? Yes _ No Without causing flowing or standing water on public roadway? Yes _ No Designs & materials comply with B-CS Technical Specifications? _ Yes _ No Explain any "no" answers: r• N 61 C oAre culverts parallel to public roadway alignment? Yes No Explain: 2 M m Q Creeks at Private Drives: Do private driveways, drives, or streets cross drainage io ways that serve Above -Project areas or are in public easements/ ROW? Z X No Yes If "yes" provide information below. N N X How many instances? Describe location and provide information below. t Location 1: U Location 2: Location 3: For each location enter value for: 1 2 3 Design year passing without toping travelway? Water depth on travelway at 25-year flow? Water depth on travelway at 100-year flow? For more instances describe location and same information on separate sheet. STORMWATER DESIGN GUIDELINES Page 19 of 26 APPENDIX. D: TECH. DESIGN SUMMARY Effective February 2007 As Revised August 2012 SECTION IX APPENDIX D - TECHNICAL DESIGN SUMMARY Part 4 —Drainage Concept and Design Parameters Continued (Page 4.11) Stormwater Management Concept (continued) Within Or Serving Subject Property (Phase, or Site) (continued) Named Regulatory Watercourses (& Tributaries): Are culverts proposed on these facilities? No Yes, then provide full report documenting assumptions, criteria, analysis, computer programs, and study findings that support proposed design(s). Is report provided? Yes _ No If "no', explain: Arterial or Maior Collector Streets: Will culverts serve these types of roadways? °c No Yes How many instances? For each identify the location and provide the information below. mInstance 1: } C 0 Instance 2: c 0 Instance 3: c 0 0 '@ Yes or No for the 100-year design flow: 1 2 3 z E o Headwater WSE 1 foot below lowest curb top? x c (, Spread of headwater within ROW or easement? E co Is velocity limited per conditions (Table C-11)? c "no" N Explain any answer(s): @ 0 0 0 0 . , M 0 3 0 o Minor Collector or Local Streets: Will culverts serve these types of streets? $ No Yes How many instances? for each identify the location and provide the information below: 0 Q @ � Instance 1: yc Instance 2: N o Instance 3: w o For each instance enter value, or "yes" / "no" for: 1 2 3 U @ r„ Design yr. headwater WSE 1 ft. below curb top? Q a) 100-yr. max. depth at street crown 2 feet or less? E Product of velocity (fps) & depth at crown (ft) = ? o Is velocity limited per conditions (Table C-11)? Limit of down stream analysis (feet)? Explain any "no" answers: STORMWATER DESIGN GUIDELINES Page 20 of 26 APPENDIX. D: TECH, DESIGN SUMMARY Effective February 2007 As Revised August 2012 SECTION IX APPENDIX D - TECHNICAL DESIGN SUMMARY Part 4 — Drainage Concept and Design Parameters Continued (Page 4.12) Stormwater Management Concept (continued) Within Or Serving Subject Property (Phase, or Site) (continued) All Proposed Culverts: For all proposed culvert facilities (except driveway/roadside ditch intersects) provide information requested in next eight boxes. Do culverts and travelways intersect at 90 degrees? _ Yes No If not, identify location(s) and intersect angle(s), and justify the design(s): Does drainage way alignment change within or near limits of culvert and surfaced approaches thereto? No _ Yes If "yes' identify location(s), describe change(s), and justification: Are flumes or conduit to discharge into culvert barrel(s)? No _ Yes If yes, identify location(s) and provide justification: Are flumes or conduit to discharge into or near surfaced approaches to culvert ends? No Yes If "yes" identify location(s), describe outfall design treatment(s): c _ c 0 U N a) : Is scour/erosion protection provided to ensure long term stability of culvert structural 0 components, and surfacing at culvert ends? Yes _ No If "no" Identify locations and provide justification(s): Will 100-yr flow and spread of backwater be fully contained in street ROW, and/or drainage easements/ ROW? —Yes _ No if not, why not? Do appreciable hydraulic effects of any culvert extend downstream or upstream to neighboring land(s) not encompassed in subject property? No Yes If "yes" describe location(s) and mitigation measures: Are all culvert designs and materials in compliance with B-CS Tech. Specifications? Yes _ No If not, explain in Special Design Section of this Part. STORMWATER DESIGN GUIDELINES Page 21 of 26 APPENDIX. D: TECH. DESIGN SUMMARY Effective February 2007 As Revised August 2012 SECTION IX APPENDIX D - TECHNICAL DESIGN SUMMARY Part 4 — Drainage Concept and Design Parameters Continued (Page 4.13) Stormwater Management Concept (continued) Within Or Serving Subject Property (Phase, or Site) (continued) Is a bridge included in plans for subject property project? _ No _ Yes If "yes" provide the following information. Name(s) and functional classification of the roadway(s)? What drainage way(s) is to be crossed? N N m '6 m A full report supporting all aspects of the proposed bridge(s) (structural, geotechnical, hydrologic, and hydraulic factors) must accompany this summary report. Is the report provided? —Yes —No If "no' explain: Is a Stormwater Provide a general description of planned techniques: Pollution Prevention Erosion Control Plan has been prepared and included in construction m Plan (SW3P) documents. Contractor to comply with NPDES Requirements. C7 established for a project construction? CO No —'Yes Special Designs — Non -Traditional Methods Are any non-traditional methods (aquatic echosystems, wetland -type detention, natural stream replication, BMPs for water quality, etc.) proposed for any aspect of subject property project? X No _ Yes If "yes" list general type and location below. Provide full report about the proposed special design(s) including rationale for use and expected benefits. Report must substantiate that stormwater management objectives will not be compromised, and that maintenance cost will not exceed those of traditional design solution(s). Is report provided? Yes _ No If "no" explain: NA STORMWATER DESIGN GUIDELINES Page 22 of 26 APPENDIX. D: TECH. DESIGN SUMMARY Effective February 2007 As Revised August 2012 SECTION IX APPENDIX D - TECHNICAL DESIGN SUMMARY Part 4 - Drainage Concept and Design Parameters Continued (Page 4.14) Stormwater Management Concept (continued) Within Or Serving Subject Property (Phase, or Site) (continued) Special Designs — Deviation From B-CS Technical Specifications If any design(s) or material(s) of traditional runoff -handling facilities deviate from provisions of B-CS Technical Specifications, check type facility(ies) and explain by specific detail element. Detention elements Drain system elements Channel features Culvert features Swales Ditches Inlets _Outfalls Valley gutters Bridges (explain in bridge report) In table below briefly identify specific element, justification for deviation(s). Specific Detail Element Justification for Deviation (attach additional sheets if needed) 1) 2) 3) 4) 5) Have elements been coordinated with the City Engineer or her/his designee? For each item above provide "yes" or "no", action date, and staff name: 1) NA 2) 3) 4) 5) Design Parameters Hydrology Is a map(s) showing all Design Drainage Areas provided? x Yes No Briefly summarize the range of applications made of the Rational Formula: Please refer to submitted drainage report for expanded details. Area less than 50 acres. Time of Concentration of 10 min. What is the size and location of largest Design Drainage Area to which the Rational Formula has been applied? 0.569 acres Location (or identifier): DA-2 STORMWATER DESIGN GUIDELINES Page 23 of 26 APPENDIX. D: TECH. DESIGN SUMMARY Effective February 2007 As Revised August 2012 SECTION IX APPENDIX D - TECHNICAL DESIGN SUMMARY Part 4 — Drainage Concept and Design Parameters Continued (Page 4.15) Design Parameters (continued) Hydrology (continued) In making determinations for time of concentration, was segment analysis used? —No x Yes In approximately what percent of Design Drainage Areas? 100 As to intensity -duration -frequency and rain depth criteria for determining runoff flows, were any criteria other than those provided in these Guidelines used? x No _Yes If "yes" identify type of data, source(s), and where applied: For each of the stormwater management features listed below identify the storm return frequencies (year) analyzed (or checked), and that used as the basis for design. Feature Analysis Year(s) Design Year Storm drain system for arterial and collector streets Storm drain system for local streets Open channels Swale/buried conduit combination in lieu of channel Swales Roadside ditches and culverts serving them Detention facilities: spillway crest and its outfall 2, 10, 25, 50, 100 2, 10, 25, 50, 100 Detention facilities: outlet and conveyance structure(s) 2, 10, 25, 50, 2, 10, 25, 50, 100 Detention facilities: volume when outlet plugged Culverts serving private drives or streets Culverts serving public roadways Bridges: provide in bridge report. Hydraulics What is the range of design flow velocities as outlined below? Design flow velocities; Gutters Conduit Culverts Swales Channels Highest (feet per second) 6.07 ft/s Lowest (feet per second) 2.15 fds Streets and Storm Drain Systems Provide the summary information outlined below: Roughness coefficients used: For street gutters: For conduit type(s) PVC Coefficients:.013 STORMWATER DESIGN GUIDELINES Page 24 of 26 APPENDIX. D: TECH. DESIGN SUMMARY Effective February 2007 As Revised August 2012 SECTION IX APPENDIX D - TECHNICAL DESIGN SUMMARY Part 4 — Drainage Concept and Design Parameters Continued (Page 4.16) Design Parameters (continued) Hydraulics (continued) Street and Storm Drain Systems (continued) For the following, are assumptions other than allowable per Guidelines? Inlet coefficients? x No —Yes Head and friction losses x No _ Yes Explain any "yes" answer: In conduit is velocity generally increased in the downstream direction? x Yes _ No Are elevation drops provided at inlets, manholes, and junction boxes? Yes x No _ Explain any "no" answers: Private storm sewer; limited vertical room for elevation drops. Are hydraulic grade lines calculated anel-0mim for design storm? x Yes No _ For 100-year flow conditions? x Yes _ No Explain any "no" answers: What tailwater conditions were assumed at outfall point(s) of the storm drain system? Identify each location and explain: Outfall to Detention Pond: Tailwater 320.25' (assumed pond is full) Pond outfall to TxDOT: 31To4' (assumes 4'x6' box culvert at Texas Ave crossing is flowing fill) Open Channels If a HEC analysis is utilized, does it follow Sec VI.F.5.a? Yesx No Outside of straight sections, is flow regime within limits of sub -critical flow? Yes No _ If "no" list locations and explain: Culverts If plan sheets do not provide the following for each culvert, describe it here. For each design discharge, will operation be outlet (barrel) control or inlet control? NA Entrance, friction and exit losses: Bridges Provide all in bridge report NA STORMWATER DESIGN GUIDELINES Page 25 of 26 APPENDIX. D: TECH. DESIGN SUMMARY Effective February 2007 As Revised August 2012 SECTION IX APPENDIX D — TECHNICAL DESIGN SUMMARY Part 4 — Drainaae Concept and Desian Parameters Continued (Page 4.17) Design Parameters (continued) Computer Software What computer software has been used in the analysis and assessment of stormwater management needs and/or the development of facility designs proposed for subject property project? List them below, being sure to identify the software name and version, the date of the version, any applicable patches and the publisher HEC-HMS Version 3.5 WinStorm Version 3.05 January 25,.2002 Part 5 — Plans and Specifications Requirements for submittal of construction drawings and specifications do not differ due to use of a Technical Design Summary Report. See Section III, Paragraph C3. Part 6 — Conclusions and Attestation Conclusions Add any concluding information here: Attestation Provide attestation to the accuracy and completeness of the foregoing 6 Parts of this Technical Design Summary Drainage Report by signing and sealing below. `This report (plan) for the drainage design of the development named in Part B was prepared by me (or under my supervision) in accordance with provisions of the Bryan/College Station Unified Drainage Design Guidelines for the owners of the property. A J(1 s and permits required by any and all state and federal regulatory agencies �t drainage improvements have been issued or fall under applicable gener i� .JgJ11, (Affix Sg�µ jSIEVE E ................ .................UNCAN Licensed Professional Engineer �j 83252....;,.. i ftl �CENSED,.�iv�i F State of Texas PENo. STORMWATER DESIGN GUIDELINES Page 26 of 26 APPENDIX. D: TECH. DESIGN SUMMARY Effective February 2007 As Revised August 2012 DRAINAGE REPORT HOME 2 SUITES HOTEL DEVELOPMENT Prepared for: City of College Station College Station Brazos County, Texas JC Job No.: C0120-001 May 20, 2013 Prepared by: 1 JONES&CARTER,ixc. ` ENGINEERS -PLANNERS -SURVEYORS Terns B.,d ofProfe.Ia,.l Engineers RegislmOoe Na. F-439 1716 Brlarcrest Dr., Suite 160 Bryan, TX 77802-2776 979-731-8000 ♦ 979-846-2893 (fax) w .ionescartermrn DRAINAGE REPORT HOME 2 SUITES HOTEL DEVELOPMENT FOR CITY OF COLLEGE STATION SCOTT & WHITE LIFT STATION BRAZOS COUNTY, TEXAS JC Job No.: C0120-001 CS File No.: 12-00500217 TABLE OF CONTENTS 1.0 EXECUTIVE SUMMARY..................................................................................................I..........2 1.1Engineer Contact Information 1.2 Project Site Information 1.3 Watershed Information 1.4 FEMA Information 2.0 EXISTING CONDITIONS.............................................................................................................. 3 2.1 Location and Topography 2.2 Land Use 2.3 Drainage Patterns 2A Existing Conditon Multi -Year Peak Flow Analysis 3.0 PROPOSED IMPROVEMENTS.....................................................................................................4 3.1 Proposed Hotel Site Improvements 3.2 Proposed Site Rational Method Analysis 4.0 STORM CONDUIT NETWORK ANALYSIS ............. 4.1 WinStorm Model & Analysis 4.2 Existing 4'x6' Box Culvert Capacity Analysis 5.0 CONCLUSION............................................................ Exhibit A — Overall Map Exhibit B — Burton Creek Watershed Exhibit C - FEMA Flood Map Exhibit D — Win Storm Output Table EXHIBITS ............. ................................ I................... 5 ................................................................. 8 1 1.0 EXECUTIVE SUMMARY 1.1 Engineer Contact Information Steve E. Duncan, P.E. Jones & Carter Inc. 1716 Briarcrest Drive, Suite 160 Bryan, Texas 77802 (979)731-8000 sdunc anlnln� i onescarter. com 1.2 Project Information The Home 2 Suites (H2S) development is located at 300 South Texas Avenue, College Station, Texas, on the following combination of properties totaling 1.97 acres: a. 1.41 Acre tract, Lot 2, Lodgeco Subdivision b. 0.20 Acre tract, Lot 2, North Park Section II c. 0.18 Acre tract, Lot 3, North Park Section I1 d. 0.18 Acre tract, Lot 4, North Park Section II These four (4) lots form an "L" shaped property with frontage on Texas Avenue and Meadowland. Additionally, the H2S development is located north of the existing Hampton Inn property and south and west of the existing Applebee's and south of a vacant lot located on the northwest corner of the 112S property. Please refer to Exhibit A — Overall Man for additional information. 1.3 Watershed Information The 112S property is located within in the Burton Creek Watershed Area as shown in Exhibit B — Burton Creek Watershed. Per the Bryan/College Station Unified Stormwater Design Guidelines (UDG) dated August 2012, this site is located in a zone that requires additional evaluation to determine the need for stormwater detention. 1.4 FEMA Information The entire property site is situated within the city limits of College Station. According to community panel no. 48041CO215E of the Federal Emergency Management Agency's flood insurance rate maps for Brazos County, Texas, effective date May 16, 2012, the subject tract is situated within unshaded zone "X", defined as areas determined to be outside the 500-year flood plain (Exhibit C — FEMA Flood Map). 2.0 EXISTING CONDITIONS 2.1 Location and Topography The II2S property is located with frontage on two parallel streets, Meadowland Drive to the west and Texas Avenue to the east. The existing 4-plex lots generally slope towards Meadowland Drive with very little topographical relief, resulting in small slopes less than 2%. Additionally, the portion of the subject tract between Meadowland and Texas Avenue can be described as small slopes (less than 2%) towards Texas Avenue with the exception of a steeply sloped 5-foot change in grade with slopes approaching 20% before returning to small slopes (less than 2%) for the remaining 85-feet prior to Texas Avenue. 2.2 Land Use This project consists of four (4) different tracts being combined via a future re -plat into one (1) single 1.97 acre property. The lots remaining from the North Park subdivision currently are fully developed multi -family residential 4-plex units and concrete parking lot. The section of the property remaining from the Lodgeco Subdivision adjacent to Meadowland Drive consists of concrete parking lot for the first 100' towards Texas Avenue, transitioning to overgrown grasses with a few trees in the middle, then the concrete remains of a former building and parking lot for the 80' prior to and adjacent to Texas Avenue. 2.3. Drainage Patterns Three (3) of the existing properties are fully developed 4-plex properties including the 4-plex structure and concrete pavement for parking and access. The runoff from the existing 4-plex properties sheet flows towards Meadowland Drive. These properties include lots 2, 3, and 4 of the North Park Section II subdivision. The stormwater runoff that enters Meadowland Drive gutter flows south along Meadowland then East along Spence towards Texas Avenue, discharging into Burton Creek Tributary C. Additionally, the remaining 1.41 acre lot 2 of the Lodgco Subdivision includes a concrete parking lot located along Meadowland Drive between the 4-plex properties and the Hampton Inn property, overgrown grass area, and the remaining pavement from a former development adjacent to Texas Avenue. The stormwater runoff from the 1.41 acre tract sheet flows into Texas Avenue to an inlet and a 4'x6' box culvert located east of the Applebee's property north of the subject tract. The 4'x6' box culvert then conveys the stormwater to Burton Creek Tributary C.3. 2.4 Existing Condition Multi -Year Peak Flow Analysis The site was modeled using the rational method to calculate peak flow. Due to the small size of the site, the minimum 10 minute time of concentration was used along with the rainfall intensity equations from Table C-1 of the Stormwater Guidelines to calculate the intensities for the storm events. The runoff coefficients (C) were based on Table C-3 from the BCS Stormwater Guidelines. N 2.5 Rainfall Intensities The intensities (in/hr) are as follows in the table below: 2-Year 10-Year 25-Year 50-Year 100-Year 6.33 8.63 9.86 11.15 11.64 2.6 Existing Conditions Runoff Coefficient Calculation Areas sf Area acres Impervious 0.95 35 229.00 0.81 Semi -Impervious 0.85 9 628.00 0.22 Pervious* 0.41 40 956.20 0.94 Weighted Average 0.68 85813.20 1.97 *poor condition grass area with avg slope 2.7 Existing Conditions Rational Method Peak Flow Rates Area (acres) C 2-Year 10-Year 25-Year 50-Year 100-Year 1.97 0.68 8.47 1 11.57 13.21 14.93 1 15.59 3.0 PROPOSED IMPROVEMENTS 3.1 Proposed Hotel Site Improvements The proposed H2S development includes the removal of the entire existing pavement and structures located on the 1.97 acre 142S site. The proposed construction includes a 12,950 sf footprint 5-level hotel, outdoor swimming pool, and 110 space concrete parking lot. The proposed development will meet the requirements of the Bryan / College Station Unified Stormwater Design Guidelines by means of a private on -site storm sewer collection system and underground detention pond, resulting in reduced post -development runoff from pre -developed. The post -development flow from the project site will be conveyed via 30-inch storm conduit into the existing 4'x6' box culvert east of the Applebee's property in TxDOT right-of-way. 3.2 Proposed Site Rational Method Analysis The proposed site was modeled using the rational method to calculate peak flow. Due to the small size of the site, the minimum 10 minute time of concentration was used along with the rainfall intensity equations from Table C-1 of the Stormwater Guidelines to calculate the intensities for the storm events. The intensities are as follows in the table below. 0 3.3 Rainfall Intensities (in/hr) 2-Year 10-Year 25-Year 50-Year 100-Year 6.33 8.63 9.86 1 11.15 11.64 The runoff coefficients (C) were based on Table C-3 from the BCS Stormwater Guidelines. The weighted C value for the whole site was determined to be 0.83. The proposed site is split into 6 drainage areas based on the storm system. All but Drainage Area 4 (DA-4) will drain into the detention system. HEC-HMS modeled using 2 inflow hydrographs for each storm, one for the Main Site and one for DA-4. See table below. 3.3 Proposed Conditions Runoff Coefficient Calculations ho Area C c d o` a ft2 Acre miZ DA-1 27,647.5 0.6347 0.0009917 0.83 DA-2 24,785.6 0.5690 0.0008891 0.83 DA-3 9,192.3 0.2110 0.0003297 0.72 DA-4 11,300.4 0.2594 0.0004053 0.79 DA-5 6,475.0 0.1486 0.0002323 0.95 DA-6 6,475.0 0.1486 0.0002323 0.95 1.9714 0.0030804 0.83 3.4 Existing Conditions Peak Flow Rates Area (acres) C 2-Year 10-Year 25-Year 50-Year 100-Year Main Site 1.71 0.84 9.09 12.40 14.17 16.01 1 16.72 DA-4 0.26 0.78 1.28 1.75 2.00 2.26 2.36 Total Developed 1.97 0.83 10.37 14.15 16.16 18.27 19.08 3.5 Detention Analysis The post -development flow from the site was split into two (2) zones. One zone includes the majority of the site which discharges into the detention system and the other zone includes the DA-4, which will be undetained. The NRCS (SCS) Dimensionless Hydrographs created for each of these two areas using the rational method peak flows were input into HEC-1-IMS as described in the methodology section above. The hydrographs were used to evaluate the impact of the development of our site on the runoff quantity and to analyze the detention system. 5 3.4 HEC-HMS Input Summary Drainage Area Area CN %Impervious tL s .miles min DA-1 0.00077149 91.4 70.2 1.50 DA-2 0.00112772 91.4 70.5 1.71 DA-3 0.00070043 89.1 57.3 2.54 DA-4 0.00046452 94.0 85.0 0.72 3.5 Proposed HEC-HMS Multi -Year Storm Event Peak Flow Analysis Storm Event Peak Flow cfs 2 3.63 10 5.10 25 6.80 50 8.70 100 10.00 3.6 Existing 4x6 Box Culvert Capacity Analysis There were no available studies, or defined drainage area plans to determine the design capacity of the 4"x6" box culvert, but based on a rational method analysis and conduit capacity analysis, it is noted that the box culvert has adequate capacity to convey the runoff resulting from the 100-year storm event based on the existing runoff conditions from the 112S site. 4.0 CONCLUSION In conclusion the proposed underground storm water detentioning system reduces the peak storm water runoff, therefore meeting the requirements of the B/CS Unified Design Standards. C Post Development Site Stormwater Detention Summary 2yr Q (cfs) 10 yr Q (cfs) 25yr Q (cfs) 50 yr Q (cfs) 100 yr Q (cfs) Pre -Developed 8.47 11.57 13.21 14.93 15.59 Detention Out 2.79 4.41 5.47 6.55 6.93 DA-4 Out 1.28 1.75 2.00 2.26 2.36 Total 3.57 5.08 6.33 7.58 8.02 Storm Event 2-Year 10-Year 25-Year 50-Year 100-Year Peak Storage(acre-ft) 0,1023 0.1512 0.1695 0.1882 0.1955 Peak Elevation (ft) 318.42 319.17 319.51 320.01 320.21 Available Storage (acre-ft) 0.2755 0.2755 0.2755 0.2755 0.2755 Storage Utilized (%) 37.1% 54.9% 61.5% 68.3% 71.0% 3.6 Hydrographs The pre -development and post -development rational method peak flows from storm event (2-year, 10-year, 25-year, 50-year, and 100-year) were used as the peak flows for NRCS (SCS) Dimensionless Hydrographs. 2 Year Hydrographs 12 --- - --- _ -_ 8 -Pre-Developed u c -Post-Developed 0 4 ------ (Undetalned) 2 -- -Post-Developed (Detained) 0 20 40 60 Time (min) 10 Year Hydrographs 16 14 12 10 ._._.. - _. - _. -Pre-Developed 12 s -Post-Developed ., 6 c 4 _ _ (Undetalned) 2 _ -Post-Developed (Detained) 0_--- 0 20 40 60 80 Time (min) 11 0 25 Year Hydrographs 18 — 16 — 14 — '� 12 ------ —Pre-Developed V 10 8 —Post-Developed bi S 6 (Undetained) 4 —Post-Developed 2 (Detained) 0 0 20 40 60 80 Time (min) 50 Year Hydrographs 20 1s b— Pre -Developed 10 —Post-Developed C (Undetained) 5 Post -Developed (Detained) 0 0 20 40 60 80 Time (min) 100 Year Hydrographs 25 -- 20 — 15 —Pre-Developed E^ 10 ---......------- —Post-Developed c (Undetained) 5 --Post-Developed (Detained) 0 -- 0 20 40 60 80 Time (min) As shown by the above table and hydrographs, more than enough detention capacity is provided to reduce the post -development flows below the pre -development peak flows for the 2yr, 10yr, 25yr, 50yr, and 100yr storm events as based on rational method calculations and NRCS (SCS) Dimensionless Hydrographs as per requirements outlined in the B/CS Unified Stormwater Design Guidelines, August 2012. 7 4.0 STORM CONDUIT NETWORK ANALYSIS 4.1 WinStorm Model & Analysis WinStorm was used to model the proposed storm sewer network. This network was divided into two models. One model includes the storm sewer network upstream of the underground detention and the other models the network downstream of the underground detention. The top of the overflow weir for the underground detention system was used as the tail water for the model of the network upstream of the underground detention. The top of the outfall pipe was used as the tail water elevation for the model of the network downstream of the underground detention. The network downstream of the underground detention pond used the maximum allowable outflow from the detention pond as its input flow from the detention in addition to the flow from DA-4. The modeled system, both upstream and downstream of the underground detention, had adequate capacity and capability to carry the 100 year event flows. Please refer to Exhibit — D WinStorm Output Table for additional information. 4.2 Existing 4x6 Box Culvert Capacity Analysis There were no available studies, or defined drainage area plans to determine the design capacity of the 4"x6" box culvert. It is noted that he box culvert receives stormwater runoff via a 5' curb inlet and 18" RCP from the Applebee's Site. The curb inlet receives flow from the subject tract and some bypass from a 15' curb inlet in front of the Hampton Inn property from the south. Based on the capacity of the curb inlet and the capacity of the 18" RCP, the peak flow contribution is significantly less that the peak capacity of the 4'x6' box culvert crossing Texas Ave. Therefore, it is noted that the box culvert has adequate capacity to convey the runoff resulting from the 100-year storm event based on the existing runoff conditions from the H2S site. The current culvert is significantly oversized for the available stormwater demand, and since our site is ultimately reducing the outflow via the stormwater detentioning no additional stormwater flows will be added to the existing box culvert crossing Texas Avenue. 5.0 CONCLUSION 1. The detention capacity provided is capable of reducing the post -development flows below the pre - development peak flows for the 2yr, 10yr, 25yr, 50yr, and 100yr storm events as based on rational method calculations and NRCS (SCS) Dimensionless Hydrographs as per requirements outlined in the B/CS Unified Stormwater Design Guidelines, August 2012. 2. The storm pipe system has the capacity to carry the 100 year event flows without issue as shown in the WinStorm model. 3. The proposed underground storm water network reduces the peak storm water runoff, therefore meeting the requirements of the B/CS Unified Design Standards. [i Exhibit A —Overall Map PROPERTY LINE —. I - W DRAINAGE _ AREA 1 V1 27,617F - - -- Q1 0.634 Acre -PROPER NE - 'SI t0 BE 'SANOONEP O NA REPLAT a - a - q � PROPERTYI/NE TO RE A9AND,L 1 Ar REP[At �a. Y � V y L �PROPERTYTf- TO 6E REPLAT 1AANOONEO .� -- PROPERTY LINE EX. 4'x6' BOX CULVERT (TXDOT) I 5 Al SIM� � I I 5' CONCRETE PAl- l 6' f9761FtW VAMWRT 4 FLOW PATH DRAINAGE AREA 4 e PFOPERrI'LNf I 1 L h II DRAINAGE It r&arcs paorr j AREA 3 g' SI:Et'1;7% ✓ `�-r -�rnyr ' i,on S&v 9,191S F ru �Ncricn PaLE -- — 4 I �� sEt orAOlzx�� 0211 k _ _ .r �` 3 a 33Y77I.'DD1kir TiEIti'TiC 5T-§ j —� 1 1AC DRAINAGE DIIAG — AREA 4 E 11,282SF 0.259AC--------------------- I N I I ^•• T� �— PROPERTY DRAINAGE — D of ® 312FT N i - PR RrYLI E ------------------- ---------------------------- ® 0.569AC �— EXHIBIT A - OVERALL MAP ,., z _ HOME 2 SUITES by HILTON PROPOSED DEVELOPMENT DRAINAGE ARI PRCPERrr uNE -- aEe e clmEa, irv. DRAINAGE AREA BOUNDARY, TYP. I4 MAY, 2013 rJONES&CARTER,Ir I � ENGINEERS• PLANNERS- SURVEY01 171fi B arc esl P,,I/i Stela l hBryan, ngieer5 Aeg0 Drive, i5'ntlon No. F-03 Texas 77802 979 731-WOO Si r a A I p u � i 5 i aE4 LYp T'""t p L U y 0 C W4 N$ 2 y 5 .�� v;,> pr \ ee� W Z N u e 0 REM ft w L WinStorm (STORM DRAIN DESIGN) PROJECT NAME Home2Suites (Out to Texas Ave.) JOB NUMBER C0120-001 PROJECT DESCRIPTION : DESIGN FREQUENCY 25 Years ANALYSYS FREQUENCY : 100 Years MEASUREMENT UNITS: ENGLISH Version 3.05, Jan. 25, 2002 Run @ 4/4/2013 3:03:05 PM OUTPUT FOR ANALYSYS FREQUENCY of: 100 Years Runoff Computation for Analysis Frequency ID C Value Area To To Used Intensity Supply Q Total Q (acre) ----- -------- (min) (min) (in/hr) (cfs) (cfs) DA-4 0.78 0.26 10.00 10.00 ---------------------------- 11.64 0.000 2.355 Det Out 0.1 0.00 ----------------------------------------------------------------------------- 10.00 10.00 0.00 13.250 13.250 On Grade Inlet Configuration Data Inlet Inlet Inlet Slopes Gutter Grate Pond Width Critic ID Type Length Long Trans n Depr. Width Type Allowed Elev. (ft) --- M M ------------ (ft) (ft) (ft) (ft) DA-4 Slott 40.00 ------------------------------------------------------------------------------- 0.50 2.00 0.014 n/a n/a n/a ---------- 12,00 322.49 On Grade Inlets Conmputation Data Inlet Inlet Total Q Intercept Q Bypass To Inlet Required Actual Ponded ID Type Capacity Allow Actual ID Length Length Width (cfs) (cfs) - ---__ (cfs) (cfs) ------------------------------------- (ft) (ft) (ft) DA-4 Slott 2.355 2.355 --------------------------------------------------------------------------------- 0.000 0.000 28.86 40.00 10.75 Cumulative Junction Discharge Computations Node Node Weighted Cumulat. Cumulat. Intens. User Additional Total I.D. Type C-Value Dr.Area To Supply Q Q in Node Disch. --------------------------------------------------------------------------------- (acres) (min) (in/hr) cfs) (cfs) (cfs) DA-4 Slott 0.780 0.26 10.00 11.64 0.000 0.00 2.355 Det Out JnctBx 0.780 0.26 10.15 11.57 13.250 0.00 15.591 JB JnctBx 0.780 0.26 10.29 11.64 13.250 0.00 15.605 OUT Outlt 0.780 0.26 10.29 11.64 13.250 0.00 15.605 Conveyance Configuration Data Run* Node I.D. Flowline Elev. US IS US IS Shape # Span Rise Length Slope n_value (ft) (ft) (ft) (ft) (ft) M ---------------------------------------- ------------ 1 DA-4 Det Out 315.70 315.00 Circ 1 0.00 1.73 48.00 1.46 0.013 WinStorm (STORM DRAIN DESIGN) PROJECT NAME Home2Suites (to Detention) JOB NUMBER C0120-001 PROJECT DESCRIPTION : DESIGN FREQUENCY 25 Years ANALYSYS FREQUENCY : 100 Years MEASUREMENT UNITS: ENGLISH Version 3.05, Jan. 25, 2002 Run @ 4/4/2013 3:01:56 PM OUTPUT FOR ANALYSYS FREQUENCY of: 100 Years _____________________________________________ Runoff Computation for Analysis Frequency. ID C Value Area To To Used Intensity Supply Q Total Q (acre) (min) (min) (in/hr) (cfs) (cfs) ----------------------------------------------------------------------------- DA-1 0.83 0.63 10.00 10.00 11.64 0.000 6.131 DA-2 0.83 0.57 10.00 10.00 11.64 0.000 5.497 DA-3 0.72 0.21 10.00 10.00 11.64 0.000 1.766 DA-5 0.95 0.15 10.00 10.00 11.64 0.000 1.644 DA-6 ----------------------------------------------------------------------------- 0.95 0.15 10.00 10.00 11.64 0.000 1.644 Cumulative Junction Discharge Computations Node Node Weighted Cumulat. Cumulat Intens User Additional Total I.D. Type C-Value Dr.Area To Supply Q Q in Node Disch. (acres) (min) (in/hr) cfs) --_________________-___ (cfs) (cfs) ________________________________________ DA-1 JnctBx 0.830 0.63 10.00 11.64 0.000 0.00 6.131 DA-2 JnctBx 0.837 1.71 11.30 11.64 0.000 0.00 16.684 DA-3 JnctBx 0.720 0.21 10.00 11.64 0.000 0.00 1.768 DA-5 JnctBx 0.853 0.78 10.46 11.64 0.000 0.00 7.775 DA-6 JnctBx 0.815 0.36 10.37 11.64 0.000 0.00 3.412 OUT --------------------------------------------------------------------------------- Outlt 0.837 1.71 11.30 11.64 0.000 0.00 16.684 Conveyance Configuration Data Run# Node I.D. Flowline Elev. US US US US Shape 4 Span Rise Length Slope n_value (ft) (ft) (ft) --_-_ (ft) (ft) M _-__-_ __________________________________ 1 DA-1 DA-5 321.55 320.90 Circ 1 0.00 1.73 130.00 0.50 0.013 2 DA-5 DA-2 320.90 319.49 Circ 1 0.00 1.73 262.00 0.54 0.013 3 DA-3 DA-6 320.60 320.21 Circ 1 0.00 1.30 78.00 0.50 0.013 4 DA-6 DA-2 320.21 320.08 Circ 1 0.00 1.30 25.00 0.52 0.013 5 ---------------------------------------------------------------------------------- DA-2 OUT 316.01 316.00 Circ 1 0.00 2.50 2.00 0.50 0.013 Conveyance Hydraulic Computations. Tailwater = 320.250 (ft) ______________________________ Hydraulic Gradeline Depth Velocity Junc Run# US Elev US Elev Fr.Slope Unif. Actual Unif. Actual Q Cap Loss (ft) (ft) M (ft) (ft) (f/s) (f/s) (cfs) (cfs) (ft) 1 322.48 321.96 0.158 0.93 1.06 4.73 4.08 6.13 10.90 0.000 2 321.96 320.53 0.254 1.06 1.06 5.17 5.17 7.78 11.31 0.000 3 321.13 320.98 0.061 0.53 0.77 3.49 2.15 1.77 5.07 0.000 4 320.98 320.82 0.226 0.77 0.77 4.16 4.16 3.41 5.17 0.000 5* 320.25 320.2E 0.165 1.37 2.50 6.07 3.40 16.68 29.01 0.000 ___________________END=====_______________________________________ * Super critical flow. NORMAL TERMINATION OF WINSTORM. Warning Messages for current project Runoff Frequency of: 100 Years 2 Det OutJB 315.00 314.85 Circ 1 0.00 2.50 44.00 0.34 0.013 3 JB OUT 314.85 314.54 Circ 1 0.00 2.50 62.00 0.50 0.013 ---------------------------------------------------------------------------------- Conveyance Hydraulic Computations. Tailwater = 317.040 (ft) Hydraulic Gradeline Depth Velocity Junc Run* US E1ev DS Elev Fr.Slope Unit. Actual Unif. Actual Q Cap Loss _____________________________________________________________________ (ft) (ft) M (ft) (ft) (f/s) (f/s) (cfs) (cfs) (ft) 1* 317.18 317.17 0.023 0.42 1.73 5.42 1.00 2.36 16.56 0.000 2 317.17 317.13 0.144 1.46 2.28 5.22 3.32 15.59 23.95 0.000 3* 317.13 317.04 0.145 1.31 2.50 6.00 3.18 15.61 29.01 0.000 * Super critical flow. NORMAL TERMINATION OF WINSTORM. Warning Messages for current project: Runoff Frequency of: 100 Years