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Storm Drain Report
STORM DRAIN SYSTEM REPORT For The Barracks II Subdivision Phase 103 & 104 In College Station, Texas �,.�1pSE OF TF���tld e * - CHADEMMEL l.... t ............................... r -ai 103495 ;�Q i ��'+tl�ss/ONAL EN�'r` May 2013 Prepared by: FG L GOODWIN — LASITER, INC ENGINEERS — ARCHITECTS — SURVEYORS 4077 Cross Park Drive, Suite 100 Bryan, Texas 77802 Phone 979-776-9700 — Fax 979-776-3838 www.goodwinlasiter. corn G-L Job No. 614008 GENERAL INFORMATION AND BACKGROUND The Barracks If Subdivision is a 108-acre development located midway between Rock Prairie Road and Cain Road in south College Station. It is bound on the west by Holleman Drive South and on the east by Old Wellborn Road. It is a multi -use development that has 424 residential lots and 6 commercial lots under its current configuration. Phase 102, Capps Drive is currently under construction along with channel improvements in accordance with an approved United States Army Corps of Engineers (USACE) permit. Two ponds of a three pond detention system designed by Kimley-Horn and Associates, Inc. (KHA) which is designed to treat the entirety of The Barracks II development has also been completed. Phases 103 and 104 are located northeast of, adjacent to, and parallel with Phase 101 and west of the proposed USACE drainage channel. It involves the construction of Airborn Avenue and extensions of Deacon Drive, Foxtrot Way, and an alley and all standard infrastructure associated with a residential subdivision. This report that follows analyzes the storm drainage system of Phases 103 and 104. DRAINAGE SYSTEM REPORT General Hydraulic and Hydrologic Characteristics Phases 103 and 104 are located in a grassy pasture portion of the 108-acre site. There is no existing development on the site. The topography in these phases is gently sloping toward the existing/proposed channel to the west. The Phases have been split up into drainage areas (RE: Exhibit No. 1) which will each outfall into the USACE drainage channel and ultimately into Detention Basin No. 1 (main basin). Drainage areas along Airborn Avenue (137, D8, D9) will exit the public right-of-way (ROW) via sidewalk drains. From the ROW, drainage areas D7 and D8 will be conveyed by a 5-foot wide concrete channel and a 10-foot wide earthen channel through the lots and across the proposed City parkland to the USACE drainage channel via private drainage easements. Refer to Appendix A for drainage area and inlet calculations. Refer to Appendix B for channel design calculations. Drainage areas D10 and D11, located along Deacon Drive, will be captured by 15-foot curb inlets which are part of the proposed culvert system crossing Deacon Drive. KHA completed an analysis of the USACE channel's flow characteristics based on the proposed cross - sections and culvert crossings (see attached Technical Memorandum, dated 11/28/12). The proposed culvert crossings of Travis Cole and Deacon Drive are based on KHA's memorandum. The KHA report also provided culvert headwater/tailwater elevations which are used to ensure proper back of curb freeboard during a 100-year event. Storm Drain Design Parameters Street Design: • Standard cross-section (3% cross -slope) or complete cross slope of 2.0% • Laydown curb, Standard curb • Concrete pavement • Sidewalk Box Drains T,Methodology: TR 55 T,Minimum 10 minutes Design Storm Event: 10-yr event (Curb Inlet); 25-yr and 100-yr (Drainage Swale) Pipe Materials: RCP and HDPE pipe Manning's n Value: 0.013 (RCP and RCBC), 0.012 (HDPE) Runoff Coefficients: 0.55 for single family residential development 0.65 for townhome development 0.40 for surrounding undeveloped acreage Design Constraints: Max water depth: Laydown curb = 4.5 in. or 0.38 ft. Standard curb = 6 in. or 0.5 ft. Min flow velocity = 2.5 fps Max flow velocity =15 fps 10-year storm runoff maintained within curb/road 100-year storm runoff maintained within the ROW Design Software: Winstorm—Version 3.05 Applicable Attachments: Exhibit 1 — Storm Sewer Drainage Area Map Appendix A — Winstorm Computational Output: System C Appendix B — Channel Design Calculations Appendix C — KHA Technical Memorandum dated 11/28/12 Appendix D — Technical Design Summary SLllIUULpUL. LXL WinStorm (STORM DRAIN DESIGN) Version 3.05, Jan. 25, 2002 Run @ 5/20/2013 8:39:34 AM PROJECT NAME The Barracks II JOB NUMBER 614002 PROJECT DESCRIPTION Drainage Master Plan - System "D" DESIGN FREQUENCY 10 Years ANALYSYS FREQUENCY 100 Years MEASUREMENT UNITS: ENGLISH OUTPUT FOR DESIGN FREQUENCY of: 10 Years _________________ Runoff Computation for Design Frequency ID C Value Area Tc Tc Used Intensity Supply Q Total Q ___________________________________ (acre) (min) (min) (in/hr) (cfs) (cfs) D-1 0.65 0.71 10.00 10.00 8.63 __--_ 0.000 3.985 D-2 0.65 0.62 10.00 10.00 8.63 0.000 3.480 D-3 0.65 0.18 10.00 10.00 8.63 0.000 1.010 D-4 0.65 0.22 10.00 10.00 8.63 0.000 1.235 D-5 0.65 0.07 10.00 10.00 8.63 0.000 0.393 D-6 0.65 0.46 10.00 10.00 8.63 0.000 2.582 D-7 0.65 1.29 10.00 10.00 8.63 0.000 7.240 D-8 0.65 1.85 10.00 10.00 8.63 0.000 10.383 D-9 0.65 2.00 10.00 10.00 8.63 0.000 11.225 D-10 0.65 0.85 10.00 10.00 8.63 0.000 4.771 D-11 ----------------------------------------------------------------------------- 0.65 0.36 10.00 10.00 8.63 0.000 2.020 Sag Inlets Configuration Data. Inlet Inlet Length/ Grate Left -Slope Right -Slope Gutter Depth Critic ID Type Perim. Area Long Trans Long Trans n DeprW Allowed Elev. (ft) _-----__ (sf) M M M ____ M (ft) (ft) (ft) D-3 Curb 5.00 n/a 0.6016.67 0.60 16.67 0.014 __-___ 0.00 0.38 306.93 D-2 Curb 5.00 n/a 0.6016.67 0.60 16.67 0.014 0.00 0.38 306.93 D-6 Curb 5.00 n/a 0.6016.67 0.60 16.67 0.014 0.00 0.39 2.50 D-7 Curb 10.00 n/a 1.5016.67 1.60 16.67 0.014 2.00 0.50 304.17' D-8 Curb 10.00 n/a 0.7016.67 0.60 16.67 0.014 2.00 0.50 303.83, D-9 Curb 10.00 n/a 0.8316.67 0.65 16.67 0.014 2.00 0.50 302.88 D-10 Curb 15.00 n/a 0.7316.67 0.65 16.67 0.014 2.00 0.50 302.00 D-11 ---------------------------------------------------------------------------------- Curb 15.00 n/a 0.6516.67 0.73 16.67 0.014 2.00 0.50 302.00 Sag Inlets Computation Data Inlet Inlet Length Grate Total Q Inlet Total Ponded Width ID Type Perim Area Capacity Head Left Right ________________________________________ (ft) (ft) (sf) (cfs) (cfs) (ft) (ft) (ft) D-3 Curb 5.00 n/a n/a 1.010 2.641 __ 0.198 1.55 __-__ 1.55 D-2 Curb 5.00 n/a n/a 3.480 2.641 0.451 2.47 2.47 D-6 Curb 5.00 n/a n/a 2.582 2.801 0.369 10.03 10.03 D-7 Curb 10.00 n/a n/a 7.240 11.059 0.377 10.30 10.08 D-8 Curb 10.00 n/a n/a 10.383 11.059 0.474 15.35 15.78 D-9 Curb 10.00 n/a n/a 11.225 11.059 0.505- 15.35 16.22 D-10 Curb 15.00 n/a n/a 4.771 15.125 0.232 2.66 2.72 D-11 -------------------------------------------------------------------------------- Curb 15.00 n/a n/a 2.020 15.125 0.131 1.97 1.93 Page 1 s U111UuLpuL. LXL OUTPUT FOR ANALYSYS FREQUENCY of: 100 Years Runoff Computation for Analysis Frequency ID C Value Area Tc Tc Used Intensity Supply Q Total Q (acre) (min) (min) (in/hr) (cfs) (cfs) ----------------------------------------------------------------------------- D-1 0.65 0.71 10.00 10.00 11.64 0.000 5.371 D-2 0.65 0.62 10.00 10.00 11.64 0.000 4.691 D-3 0.65 0.18 10.00 10.00 11.64 0.000 1.362 D-4 0.65 0.22 10.00 10.00 11.64 0.000 1.664 D-5 0.65 0.07 10.00 10.00 11.64 0.000 0.530 D-6 0.65 0.46 10.00 10.00 11.64 0.000 3.480 D-7 0.65 1.29 10.00 10.00 11.64 0.000 9.759 D-8 0.65 1.85 10.00 10.00 11.64 0.000 13.996 D-9 0.65 2.00 10.00 10.00 11.64 0.000 15.131 D-10 0.65 0.85 10.00 10.00 11.64 0.000 6.431 D-11 ----------------------------------------------------------------------------- 0.65 0.36 10.00 10.00 11.64 0.000 2.724 Sag Inlets Configuration Data Inlet Inlet Length/ Grate Left -Slope Right -Slope Gutter Depth Critic ID Type Perim. Area Long Trans Long Trans n DeprW Allowed Elev. (ft) (at) M M M M ___ (ft) (ft) (ft) -"'--------------------------' D-3 Curb 5.00 n/a 0.6016.67 0.60 16.67 0.014 0.00 0.38 306.93 D-2 Curb 5.00 n/a 0.6016.67 0.60 16.67 0.014 0.00 0.38 306.93 D-6 Curb 5.00 n/a 0.6016.67 0.60 16.67 0.014 0.00 0.39 2.50 D-7 Curb 10.00 n/a 1.5016.67 1.60 16.67 0.014 2.00 0.50 304.17 D-8 Curb 10.00 n/a 0.7016.67 0.60 16.67 0.014 2.00 0.50 303.83 D-9 Curb 10.00 n/a 0.8316.67 0.65 16.67 0.014 2.00 0.50 302.88 D-10 Curb 15.00 n/a 0.7316.67 0.65 16.67 0.014 2.00 0.50 302.00 D-11 ---------------------------------------------------------------------------------- Curb 15.00 n/a 0.6516.67 0.73 16.67 0.014 2.00 0.50 302.00 Sag Inlets Computation Data Inlet Inlet Length Grate Total Q Inlet Total Ponded Width ID Type Perim Area Capacity Head Left Right (ft) (ft) (sf) (cfs) (cfs) (ft) (ft) ---- (ft) -------------------------------------------' D-3 Curb 5.00 n/a n/a 1.362 2.641 0.241 1.73 1.73 D-2 Curb 5.00 n/a n/a 4.691 2.641 0.550 2.76 2.76 D-6 Curb 5.00 n/a n/a 3.480 2.801 0.451 11.23 11.23 D-7 Curb 10.00 n/a n/a 9.759 11.059 0.460 12.28 12.06 D-8 Curb 10.00 n/a n/a 13.996 15.675 0.491 17.54 17.98 D-9 Curb 10.00 n/a n/a 15.131 15.675 0.525 17.32 18.42 D-10 Curb 15.00 n/a n/a 6.431 15.125 0.283 2.98 3.06 D-11 Curb 15.00 n/a n/a 2.724 15.125 0.159 2.21 2.17 ------------------------ - - ------END--------_ _-------=-------------_-------_ - NORMAL TERMINATION OF WINSTORM. Warning Messages for current project: Capacity of sag inlet exceeded at inlet Id= D-2 Capacity of sag inlet exceeded at inlet Id= D-9 Page 2 SLIIIVnLpnL. LxL Capacity of sag inlet exceeded at inlet Id= D-2 Capacity of sag inlet exceeded at inlet Id= D-6 Page 3 G The Barracks II GL No. 614008 The Drainage Swales May 8, 2013 in Phases 103 104 Rainfall Intensity -Duration -Frequency Coefficients for Texas Counties 1. Select Bexar Blanco Borden Bosque Bowie me of e r&l 1 r 0.806 0.785 1651 1930 10-year 25-year 50-year' 100-year 0.763 0.754 0.745 0.730 2 332 2261 2489 2438 147�Wr"= 8.0 8.5 8.5 8.5 8.5 8.0 111 LCI Wl ly, n l l IIH I11.. ` for time of Concentration = IOUs ia0.4 zlu.3 2bu.b 283.2 295.6 10 mins rimwLuomuwvwinwon Area Desc Acres Runoff Coefficient C) 25 yr Intensity (in/hr) Q cfs D7 1.29 0.65 9.9 8.27 D8 1.85 0.65 9.9 11.86 D9 2 0.65 9.9 12.82 100-yr Runoff Determination ;y Area Desc Acres Runoff Coefficient (C) 100 yr Intensity (in/hr) Q (cfs) D7 1.29 0.65 11.6 9.76 D8 1.85 0.65 11.6 14.00 D9 2 0.65 11.6 15.13 Drainage Areas D7, D8 & D9 will outfall to the mitigation channel via private drainage swales. The private drainage swales between the townhomes and from the back of lots, across park land, to the mitigation channel will be sized to handle the 25-year event. Page 1 of 1 Channel Design Calculations *Refer to Exhibit A for proposed channel cross -sections Summary of Results Storm Event (cfs) Depth of Channel Flow (in.) Storm Event (cfs) Depth of Channel Flow (in.) 100-yr Sec. A -A Sec. B-B 25-yr Sec. A -A Sec. 8-B D7 9.76 0.37 0.32 8.27 0.33 0.29 D8 14 0.46 0.39 11.86 0.41 0.36 D9 15.13 0.48 0.39 12.82 0.43 0.38 Drainage Area D7 Sidewalk drain & 110' Concrete Channel (Section A -A); 53' Earthen Swale (Section B-B) Section A -A Section B-8 Rectangular Channel Trapizodial Channel 100-yr 25-yr 100-yr 25-yr Flow Capacity, Q= 9.76 8.27 cfs Flow Capacity, Q= 9.76 8.27 cfs Depth of Flow, D = 0.37 0.33 ft Depth of Flow, D = 0.32 0.29 ft Bottom width, B = 5 5 ft Bottom width, B = 10 10 ft Flowline Slope, S = 0.01 0.01 ft/ft Left Side Slope, L.S.S.= 16.66% 16.66% Manning's N, N = 0.013 0.013 Right Side Slope, R.S.S.= 16.66% 16.66% Area, A= 1.83 1.65 ft2 Flowline Slope, S= 0.02 0.02ft/ft Wetted Perimeter, Pw= 5.73 5.66 it Manning's N, N = 0.035 0.035 Hydraulic Radius, Rh= 0.32 0.29 it Area, A= 3.84 3.44 ft' Velocity, V= 5.34 5.02 ft/s Wetted Perimeter, Pw= 13.91 13.56 ft Hydraulic Radius, Rh = 0.28 0.25 ft Velocity, V= 2.54 2.41 ft/s Drainage Area DS Sidewalk drain & 125' Concrete Channel (Section A -A); 53' Earthen Swale (Section B-B) Section A -A Section B-B 100-yr 25-yr Flow Capacity, Q= 14.00 11.86 cfs Depth of Flow, D = 0.46 0.41 ft Bottom width, B = 5 5 ft Flowline Slope, 5= 0.01 0.01 ft/ft Manning's N, N = 0.013 0.013 Area, A = 2.30 2.07 ft2 Wetted Perimeter, Pw= 5.92 5.83 ft Hydraulic Radius, Rh= 0.39 0.36 ft Velocity, V= 6.09 5.73 ft/s 100-yr 25-yr Flow Capacity, Q= 14.00 11.86 cfs Depth of Flow, D = 0.39 0.36 ft Bottom width, B = 10 10 ft Left Side Slope, L.S.S.=. 16.66% 16.66% Right Side Slope, R.5.S.= 16.66% 16.66% Flowline Slope, S =. 0.02 0.02 ft/ft Manning's N, N = 0.035 0.035 Area, A = 4.88 4.37 ft2 Wetted Perimeter, Pw= 14.81 14.37 ft Hydraulic Radius, Rh = 0.33 0.30 ft Velocity, V= 2.87 2.71 ft/s Drainage Area D9 Sidewalk drain (Section A -A); 30' Earthen Swale (Section B-B) Section A -A Section B-B Flow Capacity, Q= 15.13 12.82 cfs Depth of Flow, D = 0.48 0.43 ft Bottom width, B = 5 5 ft Flowline Slope, S= 0.01 0.01 ft/ft Manning's N, N = 0.013 0.013 Area, A = 2.42 2.17 ft2 Wetted Perimeter, Pw= 5.97 5.87 ft Hydraulic Radius, Rh = 0.41 0.37 ft Velocitv. V= 6.26 5.90 ft/s 100-yr 25-yr Flow Capacity, Q= 15.13 12.82 cfs Depth of Flow, D = 0.41 0.38 it Bottom width, B = 10 10 ft Left Side Slope, L.S.S= 16.66% 16.66% Right Side Slope, RS.S = 16.66% 16.66% Flowline Slope, S= 0.02 0.02 ft/ft Manning's N, N = 0.035 0.035 Area, A = 5.15 4.60 ft2 Wetted Perimeter, Pw= 15.02 14.57 ft Hydraulic Radius, Rh= 0.34 0.32 ft Velocitv. V= 2.94 2.79 ft/s Kimley-Horn rEE............. and Associates, Inc. The Barracks Culvert Hydraulic Analysis Technical Memorandum To: Chad Emmel, P.E. — Goodwin-Lasiter, Inc. From: Chris Harris, P.E. — IGmley-Horn and Associates, Inc. Date: November 28, 2012 Subj: The Barracks — Culvert and Channel Hydraulic Modeling Kimley-Horn and Associates, Inc. (KHA) previously developed the pre- and post- development hydrologic/hydraulic EPA-SWMM models for the proposed Barracks Subdivision. Through the use of these models, KHA sized the necessary detention facility to detain the 2, 10, 25, 50, and 100 year events to predevelopment conditions. Based on the proposed land plan, the detention facility was comprised of three interconnected ponds that discharge through one shared outfall. The results of this analysis were presented in the report "The Barracks Detention Facility Design" dated July 2012. Due to the dynamic nature of the of the elevation in the ponds over the duration of each storm event, KHA was later asked to analyze the proposed culverts at future Deacon Drive West, Travis Cole Avenue, and Capps Drive as well as the channel upstream of these culverts that connects the outfalls of the existing Barracks Phase 1 and Williamsgate ponds. This technical memo presents the proposed culvert sizes at these crossings and outlines the resulting peak headwater elevations for the 100 year event. In order to determine the resulting performance characteristics of these aforementioned hydraulic structures, I 14A modified the previously (City of College Station) approved EPA-SWMM proposed condition model to incorporate them. KHA was then able to model the resulting / headwater and tailwater elevations on each of the culverts in sync with the routing of the ponds. Table 1 presents the 100 year event peak data for each of the culverts. Table l: Peak 100 Year Event Culvert Performance Data Capps Culvert Travis Culvert Deacon Culvert Pond Connection Prop TC 306.31 Prop TC 302.77 Prop TC 301.96 Prop TC 301.93 Length 47 Length 50 Length 68 Length 99 US FL 301.58 US FL 295.94 US FL 295.45 US FL 294.94 DS FL 301.37 DS FL 295.79 DS FL 295.25 DS FL 289.00 S 0.45% S 0.30% S 0.30% S 6.00% 3-42" 3-42" 3-48" 2-42" & 1-48" HW 305.31 HW 301.77 HW 300.96 HW 300.23 TW 304.38 TW 301.10 TW 300.23 TW 299.53 SF 1.98% SF 1.34% SF 1.08% SF 0.71% Q 307.08 Q 350.33 Q 354.83 Q 356.54 V 10.98 V 12.14 V 9.41 V(48") 11.82 Table 2 outlines the channel performance characteristics for the 100 year event. Copyright 0 2012, Kimley-Horn and Associates, Inc. 1 TBPE Registration No. F-928 WE Kimley-Horn __. _. and Associates, Inc. The Barracks Hydrologic Analvsis Technical Memorandum Table 2: 100 Year Event Channel Performance Characteristics Section Al Section B1 Section B2 Section C1 Section C2 Us Williamsgate OF DS Capps Culy. 12 J3 DS Travis DS US Capps Culy. J2 J3 US Travis US Deacon Length (ft) 115 625 275 150 110 Meander 1.16 1.07 1.07 1.1 1.1 Cross Section A -A B-B B-B C-C C-C Qp (cfs) 300.55 304.32 330,52 343.12 349.85 VP (fps) 4.41 4.73 4.18 1 3.96 1 4.49 J2 Depth (ft) 3.69 J3 Depth (ft) 1 5.26 Attachments Culvert and Junction Identification Exhibit Channel Cross Section A -A Characteristics Channel Cross Section B-B Characteristics Channel Cross Section C-C Characteristics i J. CHRIS HARRIS 94859 rR //•Zb' Zoe z- Copyright © 201Z Kimley-Horn and Associates, Inc. 2 TBPE Registration No. F-928 THE BARRACKS COLLEGE STATION, TEXAS ❑mm❑ 000 S th T—, M.., Su9. 201 8,,a - T... 7790z TOPE Rcgi.trvtion No. P-9W IGmley-Horn and Associates, Inc. T.I. No. 9l9 M-9595 Fox Na. 979 TS-9599 3 The Barracks - Detention Facility Design EPA-SWMM Channel Cross Sections Kimley-Horn & Associates Cross Section A -A X y Manning's n -27.6 4 0.058 -22.5 2.3 0.058 -7.5 2 0.030 -6 0 0.030 6 0 0.030 7.5 2 0.030 22.5 2.3 0.058 27.6 4 0.058 Transecl PropSecA-A v o,erbank • Channel dS -20 -15 -10 -5 0 - 10 1s 20 2S Station (11) Cross Section B-B X Y Manning's n -67.6 4.8 0.058 -27.6 4 0.058 -22.5 2.3 0.058 -7.5 2 0.030 -6 0 0.030 6 0 0.030 7.5 2 0.030 22.5 2.3 0.058 27.6 4 0.058 67.6 4.8 0.058 Transect PropSecB-B Station (n) r a The Barracks - Detention Facility Design 4 EPA-SWMM Channel Cross Sections Kimley-Horn & Associates Cross Section C-C X Y Manning's n -21.5 6 0.058 -21 5.32 0.058 -11 2.06 0.058 -5.5 2 0.030 -4 0 0.030 4 0 0.030 5.5 2 0.030 11 2.06 0.058 21 5.32 0.058 21.5 6 0.058 Transect PropSecC-C 0 Overbank i Channel QO -IS -10 -s 0 c10 15 20 Station (fp SECTION IX APPENDIX D — TECHNICAL DESIGN SUMMARY The Cities of Bryan and College Station both require storm drainage design to follow these Unified Stormwater Design Guidelines. Paragraph C2 of Section III (Administration) requires submittal of a drainage report in support of the drainage plan (stormwater management plan) proposed in connection with land development projects, both site projects and subdivisions. That report may be submitted as a traditional prose report, complete with applicable maps, graphs, tables and drawings, or it may take the form of a "Technical Design Summary'. The format and content for such a summary report shall be in substantial conformance with the description in this Appendix to those Guidelines. In either format the report must answer the questions (affirmative or negative) and provide, at minimum, the information prescribed in the "Technical Design Summary" in this Appendix. The Stormwater Management Technical Design Summary Report shall include several parts as listed below. The information called for in each part must be provided as applicable. In addition to the requirements for the Executive Summary, this Appendix includes several pages detailing the requirements for a Technical Design Summary Report as forms to be completed. These are provided so that they may be copied and completed or scanned and digitized. In addition, electronic versions of the report forms may be obtained from the City. Requirements for the means (medium) of submittal are the same as for a conventional report as detailed in Section III of these Guidelines. Note: Part 1 — Executive Summary must accompany any drainage report required to be provided in connection with any land development project, regardless of the format chosen for said report. Note: Parts 2 through 6 are to be provided via the forms provided in this Appendix. Brief statements should be included in the forms as requested, but additional information should be attached as necessary. Part 1 — Executive Summary Report Part 2 — Project Administration Part 3 — Project Characteristics Part 4 — Drainage Concept and Design Parameters Part 5 — Plans and Specifications Part 6 — Conclusions and Attestation STORMWATER MANAGEMENT TECHNICAL DESIGN SUMMARY REPORT Part 1 — Executive Summary This is to be a brief prose report that must address each of the seven areas listed below. Ideally it will include one or more paragraphs about each item. Name, address, and contact information of the engineer submitting the report, and of the land owner and developer (or applicant if not the owner or developer). The date of submittal should also be included. 2. Identification of the size and general nature of the proposed project, including any proposed project phases. This paragraph should also include reference to applications that are in process with either City: plat(s), site plans, zoning requests, STORMWATER DESIGN GUIDELINES Page 1 of 26 APPENDIX. D: TECH. DESIGN SUMMARY Effective February 2007 As Revised February 2009 SECTION IX APPENDIX D - TECHNICAL DESIGN SUMMARY or clearing/grading permits, as well as reference to any application numbers or codes assigned by the City to such request. 3. The location of the project should be described. This should identify the Named Regulatory Watershed(s) in which it is located, how the entire project area is situated therein, whether the property straddles a watershed or basin divide, the approximate acreage in each basin, and whether its position in the Watershed dictates use of detention design. The approximate proportion of the property in the city limits and within the ETJ is to be identified, including whether the property straddles city jurisdictional lines. If any portion of the property is in floodplains as described in Flood Insurance Rate Maps published by FEMA that should be disclosed. 4. The hydrologic characteristics of the property are to be described in broad terms: existing land cover; how and where stormwater drains to and from neighboring properties; ponds or wetland areas that tend to detain or store stormwater; existing creeks, channels, and swales crossing or serving the property; all existing drainage easements (or ROW) on the property, or on neighboring properties if they service runoff to or from the property. 5. The general plan for managing stormwater in the entire project area must be outlined to include the approximate size, and extent of use, of any of the following features: storm drains coupled with streets; detention / retention facilities; buried conveyance conduit independent of streets; swales or channels; bridges or culverts; outfalls to principal watercourses or their tributaries; and treatment(s) of existing watercourses. Also, any plans for reclaiming land within floodplain areas must be outlined. 6. Coordination and permitting of stormwater matters must be addressed. This is to include any specialized coordination that has occurred or is planned with other entities (local, state, or federal). This may include agencies such as Brazos County government, the Brazos River Authority, the Texas A&M University System, the Texas Department of Transportation, the Texas Commission for Environmental Quality, the US Army Corps of Engineers, the US Environmental Protection Agency, et al. Mention must be made of any permits, agreements, or understandings that pertain to the project. 7. Reference is to be made to the full drainage report (or the Technical Design Summary Report) which the executive summary represents. The principal elements of the main report (and its length), including any maps, drawings or construction documents, should be itemized. An example statement might be: "One -page drainage report dated , one set of construction drawings (_sheets) dated , and a -page specifications document dated comprise the drainage report for this project." STORMWATER DESIGN GUIDELINES Page 2 of 26 APPENDIX. D: TECH. DESIGN SUMMARY Effective February 2007 As Revised February 2009 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 City: Bryan College Station Date of Submittal: Lead Engineer's Name and Contact Info.(phone, e-mail, fax): 71 Other: Supporting Engineering / Consulting Firm(s): Other contacts: Developer / Owner / Applicant Information Developer / Applicant Name and Address: Phone and e-mail: Property Owner(s) if not Developer / Applicant (& address): Phone and e-mail: Project Identification Development Name: Is subject property a site project, a single-phase subdivision, or part of a multi -phase subdivision? If multi -phase, subject property is phase of Legal description of subject property (phase) or Project Area: (see Section II, Paragraph B-3a) 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. General Location of Project Area, or subject property (phase): In City Limits? Bryan: acres. College Station: acres. Extraterritorial Jurisdiction (acreage): Bryan: College Station: Acreage Outside ETJ: STORMWATER DESIGN GUIDELINES Page 3 of 26 APPENDIX. D: TECH, DESIGN SUMMARY Effective February 2007 As Revised February 2009 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 subject property: Abutting tracts, platted land, or built developments: Named Regulatory Watercourse(s) & Watershed(s): Tributary Basin(s): Plat Information For Project or Subject Property (or Phase); Preliminary Plat File #: Final Plat File #: Date: Name: Status and Vol/Pg: If two plats, second name: File #: Status: Date: Zoning, information For Project or Subject Property (or Phase) Zoning Type: Existing or 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: Preliminary Report Required? 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. STORMWATER DESIGN GUIDELINES Page 4 of 26 APPENDIX. D: TECH. DESIGN SUMMARY Effective February 2007 As Revised February 2009 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 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 _ Coordination with Summarize need(s) & actions taken (include contacts & dates): Brazos County Needed? Yes _ No _ Coordination with Summarize need(s) & actions taken (include contacts & dates): TxDOT Needed? Yes No Coordination with Summarize need(s) & actions taken (include contacts & dates): TAMUS Needed? Yes _ No _ Permits For Projector Subject Property (or Phase) As to stormwater management, are permits required for the proposed work from any of the entities listed below? If so, summarize status of efforts toward that objective ins aces below. Entity Permitted or A roved ? Status of Actions include dates ( ) US Army Crops of Engineers No Yes _ US Environmental Protection Agency No _ Yes — Texas Commission on Environmental Quality No Yes _ Brazos River Authority No Yes STORMWATER DESIGN GUIDELINES Page 5 of 26 APPENDIX. D: TECH. DESIGN SUMMARY Effective February 2007 As Revised February 2009 SECTION IX APPENDIX D - TECHNICAL DESIGN SUMMARY Part 3 — Property Characteristics Start (Page 3.1) Nature and Scope of Proposed Work Existing: Land proposed for development currently used, including extent of impervious cover? Site — Redevelopment of one platted lot, or two or more adjoining platted lots. Development Building on a single platted lot of undeveloped land. Project Building on two or more platted adjoining lots of undeveloped land. (select all applicable) Building on a single lot, or adjoining lots, where proposed plat will not form 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 projects: building use(s), approximate floor space, impervious cover ratio. Describe Subdivisions: number of lots by general type of use, linear feet of streets and Nature and drainage easements or ROW. Size of Proposed Project Is any work planned on land that is not platted If yes, explain: or on land for which platting is not pending? No Yes FEMA Floodplains Is any part of subject property abutting a Named Regulatory Watercourse No Yes (Section II, Paragraph B1) or a tributary thereof? Is any part of subject property in floodplain No Yes Rate Map area of a FEMA-regulated watercourse? Encroachment(s) into Floodplain Encroachment purpose(s): Building site(s) — Road crossing(s) 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 February 2009 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? Yes Reference the study (& date) here, and attach copy if not already in City files. Is the stormwater management plan for the property in substantial conformance with the earlier study? Yes No If not, explain how it differs. No If subject property is not part of multi -phase project, describe stormwater management plan for the property in Part 4. 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. Do existing topographic features on subject property store or detain runoff? _ No Yes Describe them (include approximate size, volume, outfall, model, etc). Any known drainage or flooding problems in areas near subject property? _ 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. _ Need must be evaluated. Detention not required. What decision has been reached? By whom? If the need for How was determination made? Type t Detention must be evaluated: STORMWATER DESIGN GUIDELINES Page 7 of 26 APPENDIX. D: TECH. DESIGN SUMMARY Effective February 2007 As Revised February 2009 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? No Yes If yes, describesplits below. In Part 4 describe design conce t for handling this. Watershed or Basin Larger acreage Lesser acreage Above -Project Areas(Section II, Paragraph B3-a) Does Project Area (project or phase) receive runoff from upland areas? _ 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 Yes Describe length and characteristics of each conveyance pathway(s). Include ownership of property(ies). STORMWATER DESIGN GUIDELINES Page 8 of 26 APPENDIX. D: TECH. DESIGN SUMMARY Effective February 2007 As Revised February 2009 SECTION IX APPENDIX D — TECHNICAL DESIGN SUMMARY Part 3 — Property Characteristics I 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 pathway(s)? _ No Yes Where runoff must cross lower properties, describe characteristics of abutting lower property(ies). (Existing watercourses? Easement or Consent aquired?) Pathway Areas Describe any built or improved drainage facilities existing near the property (culverts, bridges, lined channels, buried conduit, swales, detention ponds, etc). Nearby Drainage Facilities Do any of these have hydrologic or hydraulic influence on proposed stormwater design? No Yes If yes, explain: STORMWATER DESIGN GUIDELINES Page 9 of 26 APPENDIX. D: TECH. DESIGN SUMMARY Effective February 2007 As Revised February 2009 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. Discharge(s) To Lower Property(ies) (Section II, Paragraph E1) Does project include drainage features (existing or future) proposed to become public via platting? No _ Yes Separate Instrument? No Yes Per Guidelines reference above, how will Establishing Easements (Scenario 1) runoff be discharged to neighboring 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 # ) Scenario 2: Provide general description of how release(s) will be managed to pre -development conditions (detention, sheet flow, partially concentrated, etc.). (Attached Exhibit # ) 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. If Scenario 2, or Combination are to be used, has proposed design been coordinated with owners) of receiving property(ies)? No Yes Explain and provide documentation. STORMWATER DESIGN GUIDELINES Page 10 of 26 APPENDIX. D: TECH. DESIGN SUMMARY Effective February 2007 As Revised February 2009 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 in shifting runoff between Basins or between What design and mitigation is used to compensate for increased runoff Watersheds? from gaining basin or watershed? No 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 a m� Are other Best Management Practices for reducing stormwater pollutants proposed? a- No Yes Summarize type of BMP and extent of use: N C I — - 01 N O O Z ca design of any runoff -handling facilities deviate from provisions of B-CS Technical o_ IIf Specifications, check type facility(ies) and explain in later questions. 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 February 2009 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). 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): 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 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? a N Steepest side slopes: Usual front slopes: Usual back slopes: @ m y Flow line slopes: least Typical distance from travelway: 'v a) typical greatest (Attached Exhibit # ) v a N Z a @ ° Are longitudinal culvert ends in compliance with B-CS Standard Specifications? Yes No, then explain: At intersections or otherwise, do valley gutters cross arterial or collector streets? �. No _ Yes If yes explain: U @ Are valley gutters proposed to cross any street away from an intersection? n o No Yes Explain: (number of locations?) T mZ N � _ _ @ C Q STORMWATER DESIGN GUIDELINES Page 12 of 26 APPENDIX. D: TECH. DESIGN SUMMARY Effective February 2007 As Revised February 2009 SECTION IX APPENDIX D - TECHNICAL DESIGN SUMMARY Part 4 — Drainage Concept and Design Parameters Continued (Page 4.4) Stormwater Management Concept (continued) Within Or Serving Subject Property (Phase, or Site) (continued) Gutter line slopes: Least Usual Greatest 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. C1 a Will inlet size and placement prevent exceeding allowable water spread for 10-year gdesign storm throughout site (or phase)? _Yes No If no, explain. rn Sag curves: Are inlets placed at low points? Yes No Are inlets and 5 y _ conduit sized to prevent 100-year stormflow from ponding at greater than 24 inches? _ Yes No Explain "no" answers, m m v� m Will 100-yr stormflow be contained in combination of ROW and buried conduit on 2 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? No Yes Identify length(s) and where used. Pipe runs between system ical Typ' Longest ) access points (feet): mAre junction boxes used at each bend? Yes No If not, explain where Nand why. c O @Z a E N Are downstream soffits at or below upstream soffits? Least amount that hydraulic N Yes No If not, explain where and why: grade line is below gutter line (system -wide): STORMWATER DESIGN GUIDELINES Page 13 of 26 APPENDIX. D: TECH. DESIGN SUMMARY Effective February 2007 As Revised February 2009 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 U (include design discharge velocity, and angle between converging flow lines). 1) Watercourse (or system), velocity, and angle? N c N 0 E 2) Watercourse (or system), velocity, and angle? 0 c ,moo c o �G a) E a) E — 3) Watercourse (or system), velocity, and angle? �v O m0 0 v a E - For each outfall above, what measures are taken to prevent erosion or scour of Nreceiving and all facilities at juncture? m 1) m n d 2) N 0 3) Are swale(s) situated along property lines between properties? No Yes Number of instances: For each instance answer the following questions. Surface treatments (including low -flow flumes if any): N N v } c Flow line slopes (minimum and maximum): a` 0 Nz Outfall characteristics for each (velocity, convergent angle, & end treatment). 0 m 3 Q Will 100-year design storm runoff be contained within easement(s) or platted drainage ROW in all instances? _ Yes No If "no" explain: STORMWATER DESIGN GUIDELINES Page 14 of 26 APPENDIX. D: TECH. DESIGN SUMMARY Effective February 2007 As Revised February 2009 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? No Yes If so, provide the following: r 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 (D_ _ _ 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 0 0 K If conduit is beneath a swale, provide the following information (each instance). Instance 1 Describe general location, approximate length: v, >_ Is 100-year design flow contained in conduit/swale combination? —Yes —No N If "no" explain: 0 U 0 o Space for 100-year storm flow? ROW _ Easement Width Z c_ Swale Surface type, minimum Conduit Type and size, minimum and maximum m and maximum slopes: slopes, design storm: c U N a c m Inlets Describe how conduit is loaded (from streets/storm drains, inlets by type): c T � c � L U � 0 o Access Describe how maintenance access is provided (to swale, into conduit): o E E 3 0 = C Instance 2 Describe general location, approximate length: 0 E N � N � v Is 100-year design flow contained in conduit/swale combination? —Yes —No ° o If "no" explain: m o. c E = Space for 100-year storm flow? ROW Easement Width N Swale Surface type, minimum Conduit Type and size, minimum and maximum a) m and maximum slopes: slopes, design storm: Inlets Describe how conduit is loaded (from streets/storm drains, inlets by type): — 0 � c 3 0 N Q Access Describe how maintenance access is provided (to swale, into conduit): STORMWATER DESIGN GUIDELINES Page 15 of 26 APPENDIX. D: TECH. DESIGN SUMMARY Effective February 2007 As Revised February 2009 SECTION IX APPENDIX D - TECHNICAL DESIGN SUMMARY Part 4 — Drainage Concept and Design Parameters I 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: c Co E °" u') o 9 o u Is 100-year design flow contained in swale? _ Yes _ No is swale wholly _ r within drainage ROW? Yes No Explain "no" answers: d 0 Access Describe how maintenance access is provide: o �z U ,6 Instance 2 Describe general location, approximate length, surfacing: a) ` C1. J N N O E L N 3 Is 100-year design flow contained in swale? _ Yes _ No Is swale wholly within drainage ROW? Yes No Explain "no" answers: — o N O a� Access Describe how maintenance access is provided: U_ J 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? _ No Yes If only slightly shaped, see "Swales" in this Part. If creating side banks, provide information below. r .c Will design replicate natural channel? _ Yes No if "no", for each instance o n describe section shape & area, flow line slope (min. & max.), surfaces, and 100-year o w design flow, and amount of freeboard: w m Instance 1: c } E a) o Instance 2: Q E z _ m � c Instance 3: m t U STORMWATER DESIGN GUIDELINES Page 16 of 26 APPENDIX. D: TECH. DESIGN SUMMARY Effective February 2007 As Revised February 2009 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? No Yes If "yes" provide the information below. Will small creeks and their floodplains remain undisturbed? _ Yes _ No How many disturbance instances? Identify each planned location: 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. v c oWatercourses (and tributaries): Aside from fringe changes, are Regulatory v Watercourses proposed to be altered? 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 ° and data. Is full report submitted? Yes No If "no" explain: a E c c UAll Proposed Channel Work: For all proposed channel work, provide information 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. Will 100-year flow be contained with one foot of freeboard? _ Yes _ No If not, identify location and explain: Are ROW / easements sized to contain channel and required maintenance space? Yes _ No If not, identify location(s) and explain: STORMWATER DESIGN GUIDELINES Page 17 of 26 APPENDIX. D: TECH. DESIGN SUMMARY Effective February 2007 As Revised February 2009 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? For each provide info. below. For each dry -type facilitiy: Facility 1 Facility 2 Acres served & design volume + 10% 100-yr volume: free flow & plugged Design discharge (10 yr & 25 yr) Spillway crest at 100-yr WSE? yes no _yes no Berms 6 inches above plugged WSE? yes _ no yes _ no Explain any "no" answers: N } For each facility what is 25-yr design Q, and design of outlet structure? Facility 1: 0 z Facility 2: Do outlets and spillways discharge into a public facility in easement or ROW? Facility 1: —Yes —No Facility 2: —Yes —No If "no" explain: 0 0 a 0 a For each, what is velocity of 25-yr design discharge at outlet? & at s illwa ? Facility 1: & Facility 2: & Are energy dissipation measures used? No Describe type and LL —Yes location: G O G N N d For each, is spillway surface treatment other than concrete? Yes or no, and describe: Q Facility 1: Facility 2: For each, what measures are taken to prevent erosion or scour at receiving facility? Facility 1: Facility 2: If berms are used give heights, slopes and surface treatments of sides. Facility 1: 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; u LL Facility 2: c o c := o m� oFor additional facilities provide all same information on a separate sheet. Are parking areas to be used for detention? _ No Yes What is maximum depth due to required design storm? Roadside Ditches: Will culverts serve access driveways at roadside ditches? _ 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` rn c oAre culverts parallel to public roadway alignment? Yes No Explain: U N } n I Creeks at Private Drives: Do private driveways, drives, or streets cross drainage m ways that serve Above -Project areas or are in public easements/ ROW? Z No Yes If "yes" provide information below. How many instances? Describe location and provide information below. Location 1: 2 2 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 February 2009 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? NNo Yes How many instances? For each identify the location and provide the information below. a)@ Instance 1: Y a °v Instance 2: c o Instance 3: c 0 o .2 Yes or No for the 100-year design flow: 1 2 3 z E o Headwater WSE 1 foot below lowest curb top? c a, Spread of headwater within ROW or easement? E v ° m Is velocity limited per conditions (Table C-11)? "no" a Explain any answer(s): v, o c o m M 3 0 v o 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: as Instance 1: v y c Instance 2: � m w o Instance 3: > U For each instance enter value, or "yes" / "no" for: 1 2 3 U �0 � Design yr. headwater WSE 1 ft. below curb top? Q V, 100-yr. max. depth at street crown 2 feet or less? E Product of velocity (fps) & depth at crown (ft) = ? R 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 February 2009 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 Is scour/erosion protection provided to ensure long term stability of culvert structural c i 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 February 2009 SECTION IX APPENDIX D - TECHNICAL DESIGN SUMMARY Part 4 — Drainage Concept and Design Parameters Continued (Page 4.13) Stormwater Management Concept (continued) Within 3r 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 a 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 76 Plan (SW3P) 0 established for project construction? m 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? 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: STORMWATER DESIGN GUIDELINES Page 22 of 26 APPENDIX. D: TECH. DESIGN SUMMARY Effective February 2007 As Revised February 2009