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HomeMy WebLinkAboutDentention Pond Analysis and Report, Detention Pond Analysis and Report for Greens Prairie Center . Phase 5 College Station, Texas July 2007 Developer: Texas Hotel Management, LP 110 Pershing Street College Station, Texas 77840 · (979) 764-6806 Engineer: Civil Development, Ltd. 203 3 Harvey Mitchell Parkway South College Station, Texas 77840 (979) 764-7743 wrn.,z ·07 -/~ Detention Pond Analysis and Report for Greens Prairie Center Phase 5 College Station, Texas July 2007 Developer: Texas Hotel Management, LP 110 Pershing Street College Station, Texas 77840 (979) 764-6806 Engineer: Civil Development, Ltd. 2033 Harvey Mitchell Parkway South College Station, Texas 77840 (979) 764-7743 ENGJNEER Executive Summary Greens Prairie Center, Phase 5 Detention Facility only College Station, Texas July 20, 2007 Civil Development , Ltd. -Kent Laza, P.E. (klaza@cdlbcs.com) P.O. Box 11929 College Station, Texas 77842 Phone: (979) 764-7743 Fax: (979) 764-7759 OWNERJDEVELOPER Texas Hotel Management, LP Mr. Salim lsmail I I 0 Pershing Co llege Station, Texas 77840 Phone: (979) 764-6806 GENERAL This development involves a commercial office complex and its associated driveways, parking, landscaping and other features. Except for a small drainage system in the TxDOT right-of-way, there is no public drainage system on the site. Stormwater from the site is captured in a series of private in lets and pipes, then released into the detention facility that is analyzed with this report. A separate report detailing the system inside the commercial site will be submitted. This report is intended to analyze the detention facility onl y. The design and installation of this detention facility is part of the contractual agreement for the sale of the property, therefore it is being analyzed separately from the commercial site. The entire tract, including the commerc ial site and the detention pond, can be seen in Exhibit B. LOCATION Greens Prairie Ce nter, Phase 5 is located on the southwest comer of SH 6 and SH 40. lt lies between SH 40 and Old Anington Road. Area: Existing Land Use: Proposed Land Use : Number of Lots: Drain age Basin: FEMA FIRM: Floodplain: 10.38 acres Vacant Commerci al A-P 1 Jot Alum Creek #4804 1C0205 D No portion of this project li es within the floodplain or floodway . HYDROLOG IC C HARACTERI STI CS The existing land cover of the lot is mixed . Approximately ha lf of the site has been previously cleared and currently has a dense grass cover. The remainder of the site is den se brush and trees. The si te fa ll s gently from the north to the south and there are no significant natural drainage channels on it. GENERAL STORMW ATER PLAN As in dicated previou sly, the site wil l involve the instal lation of stormwater inlets and pipes that release into the deten ti on facility. The detention facility will provide on-si te storage and release water at a rate that is less than or equa l to pre-development conditions. A multi-stage outlet co ntrol structure is proposed to control the release of th is water for the 2, I 0, 25 , 50 and I 00-year design event s de scribed in the BCS Drainage Design Guidel ines. Since there is no re ceivi ng channel immediatel y downstream or the detention pond, water being released from the outfall pipe will be di spersed across a wide area an d run overland to the nearest channel down st ream. which is approximately 300 feet from the property line. A summary of the design information and output is provided in Exhibit A. Applicable Exhibits: Exhibit A -Data Summary Exhibit B -Pre-Development Drainage Area Map Exhibit C -Post-Development Drainage Area Map Exhibit Dl -Pre-Development HEC-HMS Output Reports Exhibit D2 -Post-Development HEC-HMS Output Reports Exhibit D3 -Post-Development HEC-HMS Output Reports (Emergency Spillway) COORDINATION & STORMWATERPERMITTING Due to the size of this project (greater than 5 acres), it will be necessary to submit a Notice of Intent to the TCEQ for this project. No coordination with other agencies is expected. REFERENCE STATEMENT The following items comprise this drainage report for this project: Executive Summary Technical Design Summary CERTIFICATION I, Kent Laza, Licensed Professional Engineer No. 65923, State of Texas, certify that this report for the drainage design for the Greens Prairie Center, Phase 5, was prepared by me in accordance with the provisions of the Unified Stormwater Design Guidelines. Kent Laza, P.E. Page2nl"2 I Exhibit A Greens Prairie Center, Phase 5 Data Summary INPUT SUMMARY Pre-Development Data Basin# Area (ac) CN %Imp. tc (min) I Lag (min) 101 8.78 75 0 33 I 22 102 2.56 75 0 30 20 Post-Development Data Basin# Area (ac) CN %Imp. tc (min) I Lag (min) 201 9.24 94 85 10 6 202 1.14 94 85 10 6 203 0.91 77 0 10 6 Note: Basins 204 & 205 shown in the Drainage Area Map are in the TxDOT right-of-way and not included in this analysis. They were used in the design of the inlets & pipes for the driveway and TxDOT ditches. Detention Pond Outfall Structure: 5'x 3' multi-stage outlet 6" circular ofifice @ 301.50 ft. 8" circular orifice @ 303.50 ft. 12" circular orifice @ 303.50 ft. 24" circular orifice @ 304 .50 ft. Outfall: Pipe = 30" HOPE Length = 60 ft Slope= 0.50% n=0.013 Emergency Spillway: Shape = trapazoidal channel Bottom Width = 20' Side slopes= 4:1 Slope= 0.50% n = 0.024 Methology: HEC-HMS (SCS Options) ANALYSIS SUMMARY Recurrance Peak Flowrate from site ------.. Interval Pre Dev Post Dev Conditions Condtions Yr cfs cfs 2 13.93 13.83 10 30.93 27.83 25 37.02 34 .62 50 49.23 43.47 100 52.99 45.03 100 64.45 Top of Berm Elev . = Emergency Spillway Elev. = Pond Elevation ft 305.22 305.84 305.98 306.28 306.38 307.33 (with blocked outlet structure) 308.00 306.50 D/A# 101 102 T 51""" = 0. 007(L 'n) 0 8 (P 2Jos'(S)o• T ,.,. .. = time of concentration for sheet flow (hr) L = length (ft) n = Manning's n P2 = 2·yr rainfall intensity (in/hr) for Brazos Co. S = slope (ft/ft) 4.5 Exhibit A (cont.) Greens Prairie Center, Phase 5 Data Summary Time of Concentration (TR-55 Method) V00"" = water velocity in ditch (ft/sec) S = slope of ditch (ft/ft) PRE-DEVELOPMENT CONDITIONS Sheet Flow Concentrated Flow -1 Concentrated Flow -2 Le~gth T SloEe T. T """ Length Slope Velocity . T unp~9d _ Lenglh _ i fl I % I min. fl % I fVsec min fl min 0.24 250 1.8 26 329 1.8 2.2 I 3 371 2 0.24 250 2 25 210 2 2.3 2 205 1.47 2 V0011., = 20.3282(S)o.s V9u11., = water velocity in gutter (fUsec) S = slope of gutter (ft/ft) T = L/(60.V) T = travel time through ditch or gutter (min) L = length of travel path (ft) V = velocity (ft/sec) Concentrated Flow -3 T, Length Slope Velocity ~ T .... ~:; Total Design ----fl % fVsec min min 202 1.41 I 1.9 2 33 I 33 192 1.69 2.1 2 30 30 j ( I ( (XH181T B CENTER. PHASE 5 GREENS PRAIRIE T "ONDITIONS LOPMEN ,, Pl~E-DEVE STATION. TX COL LE GE I / j I _) ) / / , '/ (XHIBIT c /' .. -................. _ ENTER. PHASE 5 GF<E'ENS PRAIR~~~NT CONDITIONS POS l -DEVELOE STAllON. TX COL LEG -------- TL_ -PMENT. IM* '(rclVII,~ .......•. , '.· •. ,.'",' \ l.ht<'" p ''~ . ·2: ];'_"'''' -J-:•.11·• ,.,,. • • '... 1 •• ,. , -· ''~" • -.-.. -·-.! • -~ ~~~00~ .-J --/' HEC-HMS 101 I Exhibit 01 Project : GPC 5 Basin Model : Pre Developed Conditions Jul 20 17:05:40 CDT 2007 102 Total Runoff I I Exhibit 01 Project: Greens Prairie Center Ph 5 Simulation Run : GPC5 100 yr Ex Cond Start of Run : 01 Jun2004, 00:00 Basin Model: Pre Developed Conditio End of Run : 02Jun2004, 00:05 Meteorologic Model: 100-yr Storm Compute Time: 10Jul2007, 13:36:58 Control Specifications: 24-hr Duration Volume Units: IN Hydrologic Drainage Area Peak Discharge Time of Peak Volume Element (Ml2) (CFS) (IN) 101 0.0137 40.71 01 Jun2004, 12:25 7.78 102 0.0040 12.28 01 Jun2004, 12:25 7.78 Total Runoff 0.0177 52.99 01 Jun2004, 12:25 7.78 Exhibit 01 Project: Greens Prairie Center Ph 5 Simulation Run: GPC5 50 yr Ex Cond Start of Run : 01 Jun2004, 00:00 Basin Model: Pre Developed Conditio1 End of Run : 02Jun2004, 00:05 Meteorologic Model: 50-yr Storm Compute Time: 10Jul2007, 13:49:48 Control Specifications: 24-hr Duration Volume Units: IN Hydrologic Drainage Area Peak Discharge Time of Peak Volume Element (Ml2) (CFS) (IN) 101 0.0137 37.82 01 Jun2004, 12:25 7.21 102 0.0040 11.41 01 Jun2004, 12:25 7.21 Total Runoff 0.0177 49.23 01 Jun2004, 12:25 7.21 I Exhibit 01 Project: Greens Prairie Center Ph 5 Simulation Run : GPC5 25 yr Ex Cond Start of Run: 01 Jun2004, 00 :00 Basin Model: Pre Developed Conditio1 End of Run: 02Jun2004, 00 :05 Meteorologic Model: 25-yr Storm Compute Time: 10Jul2007, 13:44:09 Control Specifications: 24-hr Duration Volume Units: IN Hydrologic Drainage Area Peak Discharge Time of Peak Volume Element (Ml2) (CFS) (IN) 101 0.0137 28.42 01 Jun2004, 12:25 5.38 102 0.0040 8.60 01 Jun2004, 12:25 5.38 Total Runoff 0.0177 37 .02 01 Jun2004, 12:25 5.38 I Exhibit 01 Project: Greens Prairie Center Ph 5 Simulation Run : GPC5 10 yr Ex Cond Start of Run : 01 Jun2004, 00:00 Basin Model: Pre Developed Conditio End of Run: 02Jun2004, 00:05 Meteorologic Model: 10-yr Storm Compute Time: 10Jul2007, 13 :42:27 Control Specifications: 24-hr Duration Volume Units: IN Hydrologic Drainage Area Peak Discharge Time of Peak Volume Element (Ml2) (CFS) (IN) 101 0.0137 23 .74 01 Jun2004, 12:25 4.48 102 0.0040 7.19 01Jun2004, 12:25 4.48 Total Runoff 0.0177 30 .93 01 Jun2004, 12:25 4.48 I Exhibit 01 Project: Greens Prairie Center Ph 5 Simulation Run: GPC5 2 yr Ex Cond Start of Run : 01 Jun2004, 00 :00 Basin Model: Pre Developed Conditio1 End of Run : 02Jun2004, 00 :05 Meteorologic Model: 2-yr Storm Compute Time: 10Jul2007, 13:48:21 Control Specifications: 24-hr Duration Volume Units: IN Hydrologic Drainage Area Peak Discharge Time of Peak Volume Element (Ml2) (CFS) (IN) 101 0.0137 10.67 01 Jun2004, 12:25 2.04 102 0.0040 3.26 01 Jun2004, 12:25 2.04 Total Runoff 0.0177 13.93 01 Jun2004, 12:25 2.04 I I I HEC-HMS Exhibit 02 Project : GPC 5 Basin Model : Developed Condions Jul 20 17:05:27 CDT 2007 201 Detention Pond . ' 202 203 Total Runoff Exhibit 02 Project: GPC 5 Simulation Run: GPC5 1 OOyr Developed Cond Start of Run: 01 Jun2004, 00:00 Basin Model: Developed Condions End of Run : 02Jun2004, 00:05 Meteorologic Model: 100-yr Storm Compute Time: 20Jul2007, 15: 16:43 Control Specifications: 24-hr Duration Volume Units: IN Hydrologic Drainage Area Peak Discharge Time of Peak Volume Element (Ml2) (CFS) (IN) 201 0.0144 75.93 01 Jun2004, 12:05 10.90 202 0.0018 9.36 01 Jun2004, 12:05 10.90 203 0.0014 6.48 01 Jun2004, 12:05 8.64 Detenti on Pon ~0.0144 32 .06 01 Jun2004, 12:25 10.71 Jct 1 0.0159 36 .05 01Jun2004 , 12:15 10.53 Outlet Pipe 0.0144 32.06 01 Jun2004, 12:25 10.71 Total Runoff 0.0176 45 .03 01 Jun2004, 12: 10 10.57 I I I Exhibit 02 Project : GPC 5 Simulation Run : GPC5 1 OOyr Developed Cond Reservoir: Detention Pond Start of Run : 01Jun2004, 00:00 End of Run : 02Jun2004, 00 :05 Basin Model : Meteorologic Model : Developed Condions 100-yr Storm Compute Time : 20Jul2007, 15:16:43 Control Specifications : 24-hr Duration Volume Units : IN Peak Inflow : 75.93 (CFS) Peak Outflow : 32.06 (CFS) Total Inflow : 10.90 (IN) Total Outflow : 10.71 (IN) Date/Time of Peak Inflow : 01Jun2004, 12:05 Date/Time of Peak Outflow : 01Jun2004, 12:25 Peak Storage : 2.44 (AC-FT) Peak Elevation : 306.38 (FT) Exhibit 02 Project: GPC 5 Simulation Run: GPC5 50 yr Developed Cond Start of Run : 01Jun2004, 00:00 Basin Model: Developed Condions End of Run: 02Jun2004, 00:05 Meteorologic Model: 50-yr Storm Compute Time: 20Jul2007, 15: 17: 10 Control Specifications: 24-hr Duration Volume Units: IN Hydrologic Drainage Area Peak Discharge Time of Peak Volume Element (Ml2) (CFS) (IN) 201 0.0144 71 .70 01 Jun2004, 12:05 10.29 202 0.0018 8.84 01 Jun2004, 12:05 10.29 203 0.0014 6.05 01 Jun2004, 12:05 8.06 Detention Pon ~0.0144 31 .23 01 Jun2004, 12:25 10.13 Jct 1 0.0159 35.02 01 Jun2004, 12: 15 9.94 Outlet Pipe 0.0144 31.22 01 Jun2004, 12:25 10.12 Total Runoff 0.0176 43.47 01Jun2004, 12:10 9.98 I Exhibit 02 Project : GPC 5 Simulation Run : GPC5 50 yr Developed Cond Reservoir: Detention Pond Start of Run : 01Jun2004, 00 :00 End of Run : 02Jun2004, 00 :05 Basin Model : Meteorologic Model : Developed Condions 50-yr Storm Compute Time : 20Jul2007 , 15:17:10 Control Specifications : 24-hr Duration Volume Units : IN Computed Results ------------·---·-· Peak Inflow : 71 .70 (CFS) Peak Outflow: 31 .23 (CFS) Total Inflow : 10.29 (IN) Total Outflow : 10.13 (IN) Date/Time of Peak Inflow : 01Jun2004, 12:05 Date/Time of Peak Outflow : 01Jun2004, 12:25 Peak Storage : 2.30 (AC-FT) Peak Elevation : 306.28 (FT) Exhibit 02 Project: GPC 5 Simulation Run: GPC5 25 yr Developed Cond Start of Run: 01 Jun2004, 00 :00 Basin Model: Developed Condions End of Run : 02Jun2004, 00 :05 Meteorologic Model: 25-yr Storm Compute Time: 20Jul2007, 15: 17:00 Control Specifications: 24-hr Duration Volume Units: IN Hydrologic Drainage Area Peak Discharge Time of Peak Volume Element (Ml2) (CFS) (IN) 201 0.0144 57.92 01 Jun2004, 12:05 8.31 202 0.0018 7.14 01 Jun2004, 12:05 8.31 203 0.0014 4.65 01 Jun2004, 12:05 6.19 Detention Pon1 ~0.0144 28 .18 01 Jun2004, 12:25 8.22 Jct 1 0.0159 30 .57 01 Jun2004, 12:20 8.04 Outlet Pipe 0.0144 28.17 01 Jun2004, 12:25 8.22 Total Runoff 0.0176 34.62 01Jun2004, 12:20 8.06 Exhibit 02 Project : GPC 5 Simulation Run : GPC5 25 yr Developed Cond Reservoir: Detention Pond Start of Run : 01Jun2004, 00:00 Basin Model : Developed Condions End of Run : 02Jun2004, 00:05 Meteorologic Model : 25-yr Storm Compute Time: 20Jul2007, 15:17:00 Control Specifications : 24-hr Duration Volume Units : IN I Compu~:::~:ftu~~-: -·-5-7-.-92_(_:~-~-;----D-a-t-e/T_i_m_e -of-~·:::;~;-lo_w_: -01 Ju~~o~:-1-2~0~--- I Peak Outflow : 28.18 (CFS) II Total Inflow : 8.31 (IN) Total Outflow : 8.22 (IN) Date/Time of Peak Outflow : 01 Jun2004, 12:25 Peak Storage : 1.89 (AC-FT) Peak Elevation : 305.98 (FT) L I I I Exhibit 02 Project: GPC 5 Simulation Run: GPC5 10 yr Developed Cond Start of Run: 01 Jun2004, 00 :00 Basin Model: Developed Condions End of Run : 02Jun2004, 00:05 Meteorologic Model: 10-yr Storm Compute Time: 20Jul2007, 15: 16:52 Control Specifications: 24-hr Duration Volume Units: IN Hydrologic Drainage Area Peak Discharge Time of Peak Volume Element (Ml2) (CFS) (IN) 201 0.0144 50.99 01 Jun2004, 12:05 7.31 202 0.0018 6.29 01 Jun2004, 12:05 7.31 203 0.0014 3.96 01 Jun2004, 12:05 5.27 Detention Pon ~0.0144 22.80 01 Jun2004, 12:25 7.26 Jct 1 0.0159 24.68 01 Jun2004, 12:25 7.08 Outlet Pipe 0.0144 22.78 01Jun2004, 12:25 7.26 Total Runoff 0.0176 27.83 01 Jun2004, 12:20 7.10 I Exhibit 02 Project : GPC 5 Simulation Run : GPC5 10 yr Developed Cond Reservoir: Detention Pond Start of Run : 01 Jun2004, 00 :00 Basin Model : End of Run : 02Jun2004, 00:05 Meteorologic Model : Developed Condions 10-yr Storm Compute Time: 20Jul2007, 15:16:52 Control Specifications : 24-hr Duration Volume Units : IN Computed Results Peak Inflow : 50 .99 (CFS) Peak Outflow : 22.80 (CFS) Total Inflow : 7.31 (IN) Total Outflow : 7.26 (IN) Date/Time of Peak Inflow : 01Jun2004, 12:05 Date/Time of Peak Outflow : 01 Jun2004, 12:25 Peak Storage : 1. 7 4 (AC-FT) Peak Elevation : 305.84 (FT) Exhibit 02 Proj ect: GPC 5 Simulation Run : GPC5 2 yr Developed Cond Start of Run : 01 Jun2004, 00:00 Basin Model: Developed Condions End of Run : 02Jun2004, 00:05 Meteorologic Model: 2-yr Storm Compute Time: 20Jul2007, 15: 17:05 Control Specifications: 24-hr Duration Volume Units: IN Hydrologic Drainage Area Peak Discharge Time of Peak Volume Element (Ml2) (CFS) (IN) 201 0.0144 30.87 01Jun2004, 12:05 4.41 202 0.0018 3.80 01Jun2004, 12:05 4.41 203 0.0014 2.03 01Jun2004, 12:10 2.70 Detention Poni ~0.0144 8.96 01 Jun2004, 12:35 4.41 Jct 1 0.0159 10.16 01 Jun2004, 12: 15 4.26 Outlet Pipe 0.0144 8.96 01 Jun2004, 12:35 4.41 Total Runoff 0.0176 13.83 01Jun2004, 12:10 4.27 I I Exhibit 02 Project : GPC 5 Simulation Run : GPC5 2 yr Developed Cond Reservoir: Detention Pond Start of Run : 01Jun2004, 00 :00 End of Run : 02Jun2004, 00:05 Basin Model : Meteorologic Model : Developed Condions 2-yr Storm Compute Time : 20Jul2007, 15:17:05 Control Specifications : 24-hr Duration Volume Units : IN ·· Computed Results-- Peak Inflow : 30.87 (CFS) Peak Outflow: 8.96 (CFS) Total Inflow : 4.41 (IN) Total Outflow : 4.41 (IN) Date/Time of Peak Inflow : 01Jun2004, 12:05 Date/Time of Peak Outflow : 01Jun2004, 12:35 Peak Storage : 1.13 (AC-FT) Peak Elevation : 305.22 (FT) Exhibit 03 Project: GPC 5 Simulation Run: GPC5 100 yr Dev w/ Emgcy Spill Start of Run : 01 Jun2004, 00:00 Basin Model: Dev Cond -emerg spill\/\ End of Run : 02Jun2004, 00:05 Meteorologic Model : 100-yr Storm Compute Time: 20Jul2007, 15: 12:59 Control Specifications: 24-hr Duration Volume Units: IN Hydrologic Drainage Area Peak Discharge Time of Peak Volume Element (Ml2) (CFS) (IN) 201 0.0144 75.93 01 Jun2004, 12:05 10.90 202 0.0018 9.36 01 Jun2004, 12:05 10.90 203 0.0014 6.48 01 Jun2004, 12:05 8.64 Detenti on Pon W.0144 52.49 01 Jun2004, 12: 15 10.84 Jct 1 0.0159 57.47 01Jun2004, 12:15 10.65 Total Runoff 0.0176 64.45 01Jun2004, 12:15 10.67 I I Exhibit 03 Project : GPC 5 Simulation Run : GPC5 100 yr Dev w/ Emgcy Spill Reservoir: Detention Pond Start of Run : 01Jun2004, 00:00 Basin Model : Dev Cond -emerg spillway End of Run : 02Jun2004, 00:05 Meteorologic Model : 100-yr Storm Compute Time : 20Jul2007, 15:12:59 Control Specifications : 24-hr Duration Volume Units : IN Computed Results ----- Peak Inflow : Peak Outflow : Total Inflow : Total Outflow : 75.93 (CFS) 52.49 (CFS) 10.90 (IN) 10.84 (IN) Date/Time of Peak Inflow : 01 Jun2004, 12:05 Date/Time of Peak Outflow : 01Jun2004, 12:15 Peak Storage : 3.98 (AC-FT) Peak Elevation : 307.33 (FT) I 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 Ill (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 Ill 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. 1. 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. STORMWATER DESIGN GUI DELINES Effective February 2007 Page 1 of 26 APPENDIX. D TECH. DESIGN SUMMARY As Revised ___ _ I SECTION IX APPENDIX D -TECHNICAL DESIGN SUMMARY 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, 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 ET J 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 I 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 _!ii_-page drainage report dated 7/io/ 07 one set of construction drawings (--'--sheets) dated -, h-., /v'1, and a /\/ IJ.. -page specifications document dated tf.J,4 ' comprise the drainage report for this project." STORMWATER DESIGN GU IDELINES Effective February 2007 Page 2 of 26 APPENDIX. D TECH. DE SIGN SUMMARY As Revised ___ _ SECTION IX APPENDIX D -TECHNICAL DESIGN SUMMARY Part 2 -Project Administration I Start (Page 2.1) Engineering and Design Professionals Information Engineerin~Firm Name and Address: Jurisdiction C1v1 ·/ LJev e lf merrf /_-Id 1 City: ~yyan ,:Zo 33 H~rve>r /Y)t"/ cf, .rl/ /Jar tru,,rr S~f~ ~---==if"===---=-CC...:...col_:_le.::.._ge_st_at_io_n--J c,,J/e qe ::;;~/,~,,/ 'h 778'10 Date of Submittal: Lead Engineer's Name and Contact lnfo.(phone, e-mail, fax): Other: Kenf La2tA. 76'1-7743 Supporting Engineering I Consulting Firm(s) Other contacts: Developer I Owner I Applicant Information Developer f Applicant N_ame and Addres~: / _ . Phone and e-mail: T).. /fofe/ /YJ'jr>-Ji J_f! Q/v So,;,,, L s,,..-,,,,/ ·7/ n-(;,BOb t!OPt?rshi""j 01 C.:-//pr;,.,. 5-1,/l-r'o~, "!: 77'8'-ID Property 0wner(s) if not Developer I Applicant (&address): Phone and e-mail: Stlme Project Identification Is subject property a site project, a single-phase subdivision, or1part of a multi-phase subdivision? /}), ,//, · nA#._., If multi-phase, subject property is phase :C of S: , Legal description of subject property (phase) or Project Area: (see Section II, Paragraph B-3a) / 0. 3 8 a ere s 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 subm ittal and review dates. f), j_ --cu;r-e_,,,../-/1 Ur>t./p,-C-""' -:sfrvc+,·.o,, fh 2-'-I-lm.,..Jev~/,;;",>d General Location of Project Area, or subject property (phase): Soofh i.vi:>sf Q)rnt>r 0 ./' S'f1G Q>?d Sh 40. In City Limits? Bryan: _____ acres. College Station LO. 3§ acres. STORMWATER DESIGN GUIDELINES Effective February 2007 Extraterritorial Jurisdiction (acreage): Bryan: non e College Station: <4 rM e Acreage Outside ET J __ n_v_,.,_e_ Page 3 of 26 APPENDIX. D TECH. DESIGN SUMMARY As Revised ---- I SECTION IX APPENDIX D -TECHNICAL DESIGN SUMMARY Part 2 -Project Administration I Continued (page 2.2) Project Identification (continued) Roadways abutting or within Project Area or Abutting tracts, platted land, or built subject property: developmen.4 J 5' ac. SH b Grad't rr>o I 3 . 2 s l-f 40 Ca J vi',, '4-ft ,,M .-) J l/ c1 "''j Jv1 7. lj '{ ac. OIJ /Irr, ·n..,·-fo,, fw~ "' Named Regulatory..Mlatercourse(s) & Watershed(s): Tributary Basin(s): l;/um Creel( 1-)/uJri Creek. 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? Existing Case Code: Case Date Status: Zoning Type: Existing or Proposed? Existing Case Code: Case Date Status: Stormwater Management Planning For Project or Subject Property (or Phase) Planning Conference(s) & Date(s): Participants: n 0"1e Preliminary Report Required? NIA Submittal Date Review Date Review Comments Addressed? Yes D No D In Writing? No 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 Effective February 2007 IU/A Page 4 of 26 APPENDIX. D TECH. DESIGN SUMMARY As Revised ___ _ I SECTION IX APPENDIX D -TECHNICAL DESIGN SUMMARY Part 2 -Project Administration I 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. Coord ination Dept Contact: Date: Subject: With Other n.011t- Departments of Jurisdiction City (Bryan or College Station) Coordination With Summarize need(s) & actions taken (include contacts & dates): Non-jurisdiction City Needed?~ Yes [ J No . , Coordination with Summarize need(s) & actions taken !include contacts & dates): Brazos County Needed? Yes I .i No ~ Coordination with Summarize need(s) !3' actions taken (inclu?e contalsJ datJ/ . TxDOT Nee ed? Sub,'>'),) c!riV::_c,uoi ;;er,,..,,f //l e u e r&1 1 1-1 <J e Yes_._'. _! No I I S'jsfe,n ;,1 f'f./J 7 /.?ow . Coordination with Summarize need(s) & actions taken (include contacts & dates): T AMUS Needed? Yes .D.No .W Permits For Project or 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 in spaces below. Entity Permitted or Approved? US Army Crops of Engineers I J\ No Iv Yes I. J US Environmental Protection Agency No ' V Yes r·-NI/\ Texas Commission on Environmental Quality Yes r 7 NII\ No _1 ~- Brazos River Authority No ' V Yes L NI/\ STORMWATER DESIGN G UI DE LINES Effective February 2007 Status of Actions (include dates) 5' vb·rn1 V /l)O I .fur Con ·sf,.,, c ir ~/\ tic !1v1/-,c,,5 Page 5 of 26 APPENDIX. D TE CH. DESIGN SUMMARY As Revised ____ _ I I SECTION IX APPENDIX D -TECHNICAL DESIGN SUMMARY Part 3 -Property Characteristics I Start (Page 3.1) Nature and Scope of Proposed Work Existing: Land proposed for development currently used, including extent of impervious cover? Vacqnf. Vt'.r--l-v cr l/'t D // /s 1'rn;"~rv/p...-s 5nzs~/q,,.,,,,,/ cm cl hrv<i.' Site Development Project (select all applicable) Subdivision Development Project fl[!J. Describe Nature and Size of Proposed Project [ __ _! Redevelopment of one platted lot, or two or more adjoining platted lots. D Building on a single platted lot of undeveloped land. D Building on two or more platted adjoining lots of undeveloped land. L~ilding on a single lot, or adjoining lots, where proposed plat will not form a new street (but may include ROW dedication to existing streets). L_] Other (explain): [_::J Construction of streets and utilities to serve one or more platted lots. D Construction of streets and utilities to serve one or more proposed lots on lands represented by pending plats. Site projects: building use(s), approximate floor space, impervious cover ratio. Subdivisions: number of lots by general type of use, linear feet of streets and drainage easements or ROW. / /\ f / . ~ ;./ j fh l5 rP;:>orf Covel~ fhe /Je ~ri '. ~ ·', o•·"e ??"','}" d , I 1/7 S,; {, 7}Je kJv1 /j1 ,,er qnJ 1T'> {IVRtU.tlh OI/ tr · J a-s~oc1~f,,,J Jr(l,;11e stfde,,,..., etre 1~clvi~J /;,, 4 :5·J?""~1~ '~;:.,,L~,llo! Is any work planned on land that is not platted If yes, explain: ' or on land for which platting is not pending? ( V--No L_j Yes FEMA Floodplains Is any part of subject property abutting a Named Regulatory Watercourse I N [~ y D (Section 11 , Paragraph B1) or a tributary thereof? 0 --es -- Is any part of subject property in floodplain I No o:z( Ye s D Rate Map area of a FE MA-regulated watercourse? -· -·-· --·-· ------- Encroachment(s) D · · · D into Floodplain Encroachment purpose(s): ____ Bu1ld1ng s1te(s) ____:._Road crossing(s) areas planned? L .. .,J Utility crossing(s) [_J Other (explain): No r:::=( Yes fl)/) 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 Effective February 2007 ru fl. Page 6 of 26 APPENDIX. D TECH. DESIGN SUMMARY As Revised ____ _ I I I SECTION IX APPENDIX D -TECHNICAL DESIGN SUMMARY Part 3 -Pro~erty Characteristics I 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 CJ No CJ If not, explain how it differs. [q If subject property is not part of multi-phase project, describe stormwater management plan for the property in Part 4. If property~ 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. /. ~ f Ecwh ;Oh,,.., e t<h // /, e q n,, 1 ~eel 27,or 4-/ e '{ " 5' I , devefo;s ctl/cJ mu5-J com~// with &Ji re5ulc.to"' 5 . ./ Do existing topographic features on subject property store or detain runoff? r:::.'-.i No __cJ_ Yes Describe them (include approximate size, volume, outfall, model, etc). ~ Any known drainage or flooding problems in areas near subject property? [C2i 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) [-~etention is required. r ~ i Need must be evaluated. r _ Detention not required What decision has been reached? By whom? If the need for 4 (.Jond I'" .J p r o .r> 0 5f"'c/ w 1-lh fh1 ~ vtYt?!v/.)/17 · Type 1 Detention How was determination made? ' must be evaluated: STORMWATER DESIGN GUI DELINES Effective February 2007 Page 7 of 26 I APPENDIX. D TECH. DE SIGN SUMMARY As Revised ____ _ I I SECTION IX APPENDIX D -TECHNICAL DESIGN SUMMARY Part 3 -ProQerty Characteristics I Continu ed (Page 3.3) Hydrologic Attributes of Subject Property (or PhaJ e) (continued) Does subject property straddle a Watershed or Basin divide? [_2CNo D Yes If yes, describe splits below. In Part 4 describe desiqn concept for handling this. Watershed or Basin Larger acreage Lesser acreaqe Above-Project Areas(Section 11, Paragraph 83-a) Does Project Area (project or phase) receive runoff from upland areas? mNo LJ Yes Size(s) ofarea(s) in acres 1) 2) 3) 4) Flow Characteristics leach instance) (overland sheet, shallow concentrated, recognizable concentrated section(s), sma11 creek (non-regulatory), regulatory Watercourse or tributary); i1 £)/] e. f,orv-u1/011 J ttreqs Flow determinati on: Outline hydrologic methods and assumptions: Do~rm runoff drain from public easements or ROW onto or across subject property? C ... .i No c:J Yes If yes , describe faciliti es in easement or ROW Are chanqes in ru noff characteristics subject to chanqe in fu ture? Explain YJO Conveyance Pathways (Section 11, Paragraph C2) Must runoff from study property drain across l~erties before reaching a Regulatory Watercourse or tributary? CJ No C .J Yes Describe le ngth and characteristics of each conveyance pathway(s). Include ownership of property(ies) r ~ F/OGJ /s d,'-s/Pr5t-'ol oul c9 f. 2 e J--vr15 f7jJ ,...:J f.i -,-nA-1,l1 300 11 flectrP~J 11afur"I ch~11nel. STORMWATER DESIGN GUIDELINES Effective February 2007 Page 8 of 26 cleh.ri/,b11 /ond Clr>d tJVPI' /4 »A fo f~ e. APPENDIX. D TECH. DESIGN SUMMARY As Revised ____ _ I 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 easements exist for any part of If yes, for what part of length? % Created by? D plat, or D instrument. If instrument(s), describe their provisions. pathw )? __ No Cl Yes Pathway Areas Nearby Where runoff must cross lower properties, describe characteristics of abutting lower property(ies). (Existing watercourses? Easement or Consent aquired?) f_owt1r fro/pr~{ ,·'5 V°,:'IC-/1/f/ 11>,d vl'ld&vt?h/PJ_- lhere ore no ex15'/1",,,) eo ft?'!')Rrlfs-. C&Jn5~n-f wi/A fhe -CV/frenf fl r7;.--/7 P<Vne?r 15 .6e,~) /JeJof, ·~tfi"/ Describe any built or improved drainage facilities existing near the property (culverts, bridges, lined channels, buried conduit, swales, detention ponds, etc). fUIJne. 011 fhe f '/?"'J.1. ·rk~e 1 S- an e y;s·~~ c v lv~rf. t?r?cir>r 4' clo vc-4/cr Ori -fhe_ /;.£JOT 11~AI -of wa'f· Drainage ,__ ____________________________ _, Facilities Do any of these ave £::drl logic or hydraulic influence on proposed stormwater design? __ No ---=-Yes If yes, explain: STORMWATER DESIGN GUIDELINES Effective February 2007 Page 9 of 26 APPENDIX. D TECH. DESIGN SUMMARY As Revised ___ _ I SECTION IX APPENDIX D -TECHNICAL DES IGN SUMMARY Part 4 -Drainage Conce12t and Design Parameters I Start (Page 4.1) Stormwater Management Concept Discharge(s) From Upland Area(s) If runoff is to be received from upland areas,~at 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 /l <One Discharge(s) To Lower Property(ies) (Section 11, Paragraph E1) Does projec~e drainage features (existing or future) proposed~ome public via platting? __ No D Yes Separate Instrument? No D Yes Per Guidelines reference above, how will CJ Establishing Easements (Scenario 1) runoff be discharged to neighboring property(ies)? D Pre-development Release (Scenario 2) D Combination of the two Scenarios Scenario 1: If easements are proposed, describe where needed, and provide status of actions on each. (Attached Exhibit# ) h(j)ne Scenario 2: Provide general descriptio n of how release(s) will be managed to pre-development conditions (detention, sheet flow, partially concentrated, etc.). (Attached Exhibit# ) f>efenft'rJ yi f '-'n d 15 ouf /e-1-. R /)W 1-~&7/'VI f/-.tJV1~r-cJ w.1'1-A //Y/v/~'-5fcJ,,J f-~e f PF1cl v r'i/ h.e ~/7jJer5~.J an.A -f!ocv tJ V'f' r / 411 c.I 5'///J-1 1 -/.:r fo /ief/t..u /./. curr~1114 .ff ocu >. 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. The )1·-;·cho rj e ~1-fl be 5-,, m I '!cu--1-.P e '{1:;-/;1) rv 11 a f/ If Scenario 2, or C_ombination are to be ~s~a s prop2sed design been coordinated with owner(s) of rece1v 1ng proper;J,(1es)X ,_ J No ~ 7es Explai n ;,nd p~vi~e /, documentation. 7he. eveo;'Pr hds-jU S recp;,f/ OLtJ r-d -fhe_ cu(fv•n ,:.J f rP/"',,.!/ tJfvrJ~r . STORMWATER DESIGN GUIDELINES Effective February 2007 Page 10 of 26 APPENDIX. D TECH. DESIGN SUMMARY As Revised ____ _ I I I I SECTION IX APPENDIX D -TECHNICAL DESIGN SUMMARY Part 4 -Drainage Conce~t and Design Parameters I 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? C~o I J Yes How will runoff from Project 1. L .. J With faci lity(ies) involving other development projects. Area be mitigated to pre-2. [_] Establishing features to serve overall Project Area. development conditions? 3. ~phase (or site) project basis within Project Area. Select any or all of 1, 2, and/or 3, and explain below. 1. Shared facility (type & location of facility; design drainage area served; relationship to size of Pro ject Area): (Attached Exhibit # ) ruA- 2. For Overall Pro ject Area (type & location of facilities): (Attached Exhibit # ) v/J- 3. By phase (or site) project: Describe planned mitigation measures for phases (or sites) in subsequent questions of this Part. Are aquatic echosystems proposed? r=J No r=J Yes In which phase(s) or project(s)? C'-· "() C1J (/) c C1J ~ >-Are other Best Management Practices for reducing stormwater poll utants proposed? 0.. f c No c Yes Summarize type of BMP and extent of use: (/) c rn (/) C1J 0 0 z -!~ llf design of any runoff-handling facilities deviate from provisions of B-CS Technical Specifications, check type facility(ies) and explain in later questions. [:=J Detention elements L~. Conduit elements L.:::-...J Channel features ~ <( r Swales L ___ ! Ditches _f __ In lets ~Valley gutters r. ___ , Outfalls r_j Culvert features _r_· _, Bridges Other -- STORMWATER DESIGN GUIDELINES Effective Februa ry 2007 Page 11 of 26 APPENDIX. D TECH. DE SIGN SUMMARY As Revised ____ _ I SECTION IX APPENDIX D -TECHNICAL DESIGN SUMMARY Part 4 -Drainage Concept and Design Parameters I 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)? C: No f ; Yes Identify type and general size and In which phase(s). If detention/retention serves (will serve) o_verall 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 woperty part of larger Project Area_. is d~_n in substantial conformance with earlier analysis and report for larger area? f J Yes 11 No, then summarize the difference(s): rv/J Identify whether each of the types of drainage features listed below are included , extent of use. and general characteristics. C'-· -0 Q) (/) ~ Q) (/) >- j !JI Typical shape? I Surfaces? Steepest side slopes: I Usual front slopes: I Usual back slopes: Flow line slopes: least ____ _ Typical distance from travelway: typical ___ _ greatest ___ _ (Attached Exhibit # ) Are longitudinal culvert ends in compliance with B-CS Standard Specifications? r Yes -, No, then explain: At intersections or otherwise, do valley gutters cross arterial or collector streets? ___ No __ Yes If yes explain Are valley gutters proposed to cross any street away from an intersection? __ -No __ Yes Explain: (number of locations?) STOR MWATE R DESIGN GUI DELINES Effective February 2007 Page 12 of 26 APPENDIX. D TECH. DE SIGN SUMMARY As Revised ____ _ I I I I I I SECTION IX APPENDIX D -TECHNICAL DESIGN SUMMARY Part 4 -Drainage Concept and Design Parameters I Continued (Page 4.4) Stormwater Management Concept (continued) Within Or Serving Subject Property (Phase, or Site) (continued) C'-· "D Q) (/) :J .._ 2 5 Ol -o ~ c "D ro aJ ..c ~ .._ ·-:J -u c 0 .c u -~ § (/) Q) ~ u; Q) <( Gutter line slopes: Least Usual Greatest Are inlets recessed on arterial and collector streets? I I Yes I ! No If "no", identify where and why. bvmbv Will inlets capture 10-year design stormflow to prevent flooding of intersections (arterial with arterial or collector)? CJ Yes CJ No If no, explain where and why not. Will inlet size and placement prevent exceeding allowable water spread for 10-year design storm throughout site (or phase)? CJ Yes CJ No If no, explain . Sag curves: Are inlets placed at low points? CJ Yes CJ No Are inlets and conduit sized ~event 100-year stormflow from ponding at greater than 24 inches? CJ Yes _c=J __ No Explain "no" answers. Will 100-yr stormflow be contained in combination of ROW and buried conduit on whole length of all streets? . Yes l=i No If no, describe where and why . Do designs for curb, gutter, and inlets comply with B-CS Technical Specifications? C: Yes CJ No If not, describe difference(s) and attach justification. Are any 12-inch laterals used? r= , No r::J Yes Identify length(s) and where uAed I " fr1'vC1f~ 5u~T,./YI de5c.ok~c/ I~ ti· <.'p/)P,/,,/.-p rr'C>ul'J. ~ "' Pipe runs betweeri system I Typical Longest / -I :J ~ access points (feet): .§ \ J.)1\re junction boxes used at each bend? C i Yes I .. _J No If not, explain where ~"I and why. (/) c ro o "D_i1~1 f-------------~--------1 "' Are downstream soffits at or below upstream soffits? Least amount that hydraulic Yes L J No _(__J_ If not, explain where and why grade line is below gutter line (system-wide): STORMWATER DESIGN GUIDELINES Effective February 2007 Page 13 of 26 APPENDIX. D: TECH. DESIGN SUMMARY As Revised ----- I I SECTION IX APPENDIX D -TECHNICAL DESIGN SUMMARY Part 4 -Drainage Conce[!t and Design Parameters I Continued (Page 4.5) Stormwater Management Concept (continued) Within Or Serving Subject Property (Phase, or Site) (continued) --;n Describe watercourse(s), or system(s) receiving system discharge(s) below <lJ (include design discharge velocity, and angle between converging flow lines). u c: 1) Watercourse (or system), velocity, and angle? cu u; c: ~ ~o ~ E :::J '-- 2) Watercourse (or system), velocity, and angle? c: 0 ~ '+- c: ci o-~-~ E <ll ~ <ll E -3) Watercourse (or system), velocity, and angle? -cu 2 (/) (/) >. -s (/) <lJ 0 c: :!2 ·-> cu 0 -0 a_ E-For each outfall above, what measures are taken to prevent erosion or scour of '--<lJ 0 <lJ receivi ng and all facilities at juncture? -.s:::. (/) (/) 2 1) ~ cu 0.. 2) <lJ (/) c: 3) ~ Are swale(s) situated along property lines between properties? D No D Yes Number of instances: For each instance answer the following questions. Surface treatments (includinq low-flow flumes if any): C'-· (/) Q) ~ (/) -<lJ jC1 Flow line slopes (minimum and maximum): -0 <lJ 0 "'z Outfall characteristics for each (velocity, convergent angle, & end treatment). :::J j~~ (/) ~ <( Will 100-year design storm runoff be contained within easement(s) or platted drainage ROW in all instances? LJ Yes D No If "no" explain: STORMWATER DESIGN GUIDELIN ES Effective February 2007 Page 14 of 26 APPENDIX. D TECH. DESIGN SUMMARY As Revised ____ _ I I I I SECTION IX APPENDIX D -TECHNICAL DESIGN SUMMARY Part 4 -Drainage Conce12t and Design Parameters I Continued (Page 4.6) Stormwater Management Concept (continued) Within Or Serving Subject Property (Phase, or Site) (continued) Are roadside ditches used? CJ No CJ Yes If so, provide the following: (/) Is 25-year flow contained with 6 inches of freeboard throughout? CJ Yes CJ No QJ .r::. ,g Are top of banks separated from road shoulders 2 feet or more? CJ Yes CJ No 0 Are all ditch sections trapezoidal and at least 1.5 feet deep? CJ Yes CJ No QJ "O For any "no" answers provide location(s) and explain: (/) "O ro 0 O:'. If conduit is beneath a swale, provide the following information (each instance). Instance 1 Describe general location, approximate length: (/) QJ >- LI~ Is 100-year design flow contained in conduiUswale combination? CJ Yes CJ No If "no" explain: c 0 i!l ROW c::J Easement c::J z Space for 100-year storm flow? Width ·-ro Swale Surface type, minimum Conduit Type and size, minimum and maximum c and maximum slopes: slopes, design storm : Q C'· ·- (/) "O "O QJ ro c >-Inlets Describe how conduit is loaded (from streets/storm drains, inlets by type): c ro c .r::. ro u ~ c .2 QJ c 0.. Q 0 -ro Access Describe how maintenance access is provided (to swale, into conduit): 0 E :::J .~ 0 -c c ·- QJ "O E Instance 2 Describe general location , approximate length: QJ ro (/) (/) :::J (/) QJ c "O Q > Is 100-year design flow contained in conduiUswale combination? I . .-J Yes I -No -ro e -- c 0.. If "no" explain: _o Q) E QJ ROW L _ _l Easement r-0 .r::. Space for 100-year storm flow? Width u (/) ·-2 Swale Surface type, minimum Conduit Type and size, minimum and maximum :::J ~ "O and maximum slopes: slopes, design storm: c ro 0 0.. u QJ Ui (/) Inlets Describe how conduit is loaded (from streets/storm drains, inlets by type): ro c ~ 0 (/) ~ <( Access Describe how maintenance access is provided (to swale, into conduit): STORMWATER DESIGN GUI DELINES Effective February 2007 Page 15 of 26 APPENDIX. D TEC H. DESIGN SUMMARY As Revised ____ _ I I I 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 E ~ gw :g vi Is 100-year design flow contained in swale? D Yes D No Is swale wholly c ~ within drainage ROW? Cl Yes LJ No Explain "no" answers .;cil-----------u Access Describe how maintenance access is provide: ~ 0 3 z / 1 ~ Instance 2 Describe general location, approximate length, surfacing: Q) .i:: {'-· :::J Vl .D c 5 Q) o E £ ~ .§ ro Is 100-year design flow contained in swale? D Yes D No Is swale wholly within drainage ROW? I · Yes D No Explain "no" answers Q) Vl ~ Q) 0 3 s Vl 0 -0:: ~ u Access Describe how maintenance access is provided: 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? L l No L'.J Yes If only slightly c-· shaped, see "Swales" in this Part. If creating side banks, provide information below. " c ~ ~ Will design replicate natural channel? 0 Yes Ci No If "no", for each instance g_ ~ describe section shape & area , flow line slope (min. & max.), surfaces, and 100-year ~ w design flow, and amount of freeboard: vi vi Instance 1: c Q) Q) >- I I Instance 2: 0.. E -1 Qi \ }v ~ vi Instance 3 0 STOR MWATER DESIGN GUIDELINES Effective February 2007 Page 16 of 26 APPENDIX. D TECH. DESIGN SUMMARY As Revised ____ _ I I I SECTION IX APPENDIX D -TECHNICAL DESIGN SUMMARY Part 4 -Drainage Conce~t and Design Parameters I Continued (Page 4.8) Stormwater Management Concept (continued) Within Or Serving Subject Property (Phase, or Site) (continued) Existing channels {small creeks): Are these used? ..L.....J_ No c::J Yes If "yes" provide the information below. Will small creeks and their floodplains remain undisturbed? c::::::J Yes c::J 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. "O (lJ ::i c c Watercourses {and tributaries): Aside from fringe changes, are Regulatory 0 Watercourses proposed to be altered? c:J No c:J Yes Explain below. ~ (f) c Submit full report describing proposed changes to Regulatory Watercourses. Address (lJ existing and proposed section size and shape, surfaces, alignment, flow line changes, E (lJ length affected, and capacity, and provide full documentation of analysis procedures > e and data. Is full report submitted? c:J Yes D No If "no" explain: 0.. E - Qi c c C1l All Proposed Channel Work: For all proposed channel work, provide information .r. 0 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? r:::::J Yes c::J No If not, identify location and explain: Are ROW I easements sized to contain channel and required maintenance space? L ]Yes CJ No If not, identify location(s) and explain: STORMWATER DESIGN GUIDELINES Effective February 2007 Page 17 of 26 APPENDIX. D TECH. DESIGN SUMMARY As Revised ____ _ I I SECTION IX APPENDIX D -TECHNICAL DESIGN SUMMARY Part 4 -Drainage Conce(2t and Design Parameters j Continued (Page 4.9) Stormwater Management Concept (continued) Within Or Serving Subject Property (Phase, or Site) (continued) How many facilities for subject property project? 1-For each provide info. below. For each dry-type facilitiy: Facility 1 Facility 2 Acres served & design volume+ 10% /0,3 & 1).42 100-yr volume: free flow & plugged '-/'S, 0 3 b4, l/ s-- Design discharge ( 10 yr & 25 yr) 27. 83 3 '/, ''2- Spillway crest at 100-yr WSE? 0 yes I i--Mio 0 yes O no Berms 6 inches above plugged WSE? _m--yes O no LJ yes O no Explain any "no" answers: .-/4 qbt.>Ve f ,· !f w tr'f e te•$f 15 0 ,/2 100 I' w s·c . cJJ Q) Br For each facility what is 25-yr design Q, and desizn of outlet structury 0 Facility 1: Pre fJ ev = 37. 0 2. {)vf J:>+ (f>o s+ l.Je..--:-19. b 2 z DI Facility 2: Do outlets and spillways discharge into a public facility in easement or ROW? C'· Facility 1: I. ] Yes No Facility 2: Yes Q No " Q) If "no" explain: cJJ 0 {),, /,,.,.l,~ .. f,../ 17.-e-v/,,.,,jy) 0.,.-f/'fo'<-' ,·~ c/t'l'e1·5,,,/ -/" /1(.,_, a. e 0... &vPr l,..,,.A .f.D th e n~arP<../ nn-/,.,.,4/ e,J,..,,,.,,..e/. cJJ For each , what is vel<?city of 25-yr di/gn discharge at outlet? & at spillway? Q) -·-Facility 1: 7. 40 4s· & 4. Cff "'5 Facility 2: & u Are energy dissipati~n measures used? _D_ No m1'es ro Describe type and LL c:: location: R oc /c r (f -r a f af-j> 'i e Ou i-"J!: //. .Q c Q) o:; 0 ~ <( For each, is spillway surf~ce treatment other than concrete? Yes or n/. ~n~ describe: Facility 1: Gn15s /11)ecl U;>J"r /)tJrMa I Con c 1 l11J/1 -s, no £ Facility 2 S hov / J d t':i ch.: r'j'l!!:. ;:.'7/hi th<> 'iJ,·//w ,;'1 w/ loo 'i For each, what measures are taken to prevent erosion or scour at receiving facility? Faci lity 1: /'{)ft Facility 2: If berms are used give heights, slopes and surface treatments of sides. Facility 1: 3 0 e -f-f. Facility 2: STORMWATER DESIGN GUIDELINES Effective February 2007 Page 18 of 26 APPENDIX. D TECH. DESIGN SUMMARY As Revised ___ _ I SECTION IX APPENDIX D -TECHNICAL DESIGN SUMMARY Part 4 -Drainage Conce12t and Design Parameters I Continued (Page 4.10) Stormwater Management Concept (continued) Within Or Serving Subject Property (Phase, or Site) (continued) Do structures comply with 8-CS Specifications? Yes or no, and explain if "no": Facility 1; Yes en ~ '5 'O Cl] Q) Facility 2: LL ::::i c c:.;:::;. 0 c ·~ 0 c (.) Q) ~ Qi For additional facilities provide all same information 911 a separate sheet. 0 Are parking areas to be used for detention? 1J2[ No CJ Yes What is maximum depth due to required design storm? Roadside Ditches: Will culverts serve access driveways at roadside ditches? 0 No 0 Yes If "yes", provide information in next two boxes. Will 25-yr. flow pass without flowing over driveway in all cases? _L_]_ Yes L==1 No Without causing flowing or standing water on public roadway? Yes L .. i No Designs & materials comply with 8-CS Technical Specifications? _.D._ Yes r:::J No ~ Explain any "no" answers: C'-· en 0) c en Are culverts parallel to public roadway alignment? [ I Yes _r::::J_ No Explain: en e (.) en Q) 2 >- !DI Creeks at Private Drives: Do private driveways, drives, or streets cross drainage Cl] wr::!t at serve Above-Project areas or are in public easements/ ROW? "O 0 No D Yes If "yes" provide information below. Q) z ~Ft How many instances? Describe location and provide information below. Q) Location 1: 2 ::::i (.) Q) Location 2: .:'.{ Location 3: For ea ch location enter va lue 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 sam e information on separate sheet. STORMWATER DESIGN GUI DELIN ES Effective February 2007 Page 19 of 26 APPENDIX. D TECH. DESIGN SUMMARY As Revised ____ _ SECTION IX APPENDIX D -TECHNICAL DESIGN SUMMARY Part 4 -Drainage Conce['!t and Design Parameters I Continued (Page 4.11) Stormwater Management Concept (continued) Within Or Serving Subject Property (Phase, or Site) (continued) Named Regulato[Y Watercourses {&Tributaries}: Are culverts proposed on these facilities? ..r:::L_ No .r:::L Yes, then provide full report documenting assumptions, criteria , analysis, computer programs, and sL dyJfindings that support proposed design(s). Is report provided? L _J Yes =No If "no", explain: a; Arterial or Major Collector Streets: Will culverts serve these types of roadways? <lJ LJ No D Yes How many instances? For each identify the .r:: en 2 location and provide the information below. en ro Instance 1: <lJ ~ >-~ Cl~ Instance 2: Instance 3: c 0 o~ Yes or No for the 100-year design flow: 1 2 3 z E Et! Headwater WSE 1 foot below lowest curb top? Spread of headwater within ROW or easement? E C'· (1J Is velocity limited per conditions (Table C-11)? en en g1-o Explain any "no" answer(s): ·-c ~ (1J 0 c ~ 0 u:;:::; >-(1J (1J u 3 .9 "O <lJ (1J .D Minor Collector or Local Streets: Will cu lverts serve these types of streets? 0 ·-~ ~ u u D No J::l Yes How many instances? for each identify the ·-en -<lJ .g "O location and provide the information below: D.. <lJ -D.. Instance 1: roe "O >-Instance 2: <lJ c ~ (1J .,_ Instance 3: en o ten <lJ <lJ For each instance enter value, or "yes" /"no" for: 1 2 3 2 u :::Jc u (1J Design yr. headwater WSE 1 ft. below curb top? No No <lJ u; 0 ~ c ~ ·-100-yr. max. depth at street crown 2 feet or less? No No No ~ 0 Product of velocity (fps) & depth at crown (ft) = ? No No E 0 g Is velocity limited per conditions (Table C-11)? No No 0 Limit of down stream analysis (feet)? No No 0 Explain any "no" answers: STORMWATER DESIGN GUIDELINES Effective February 2007 Page 20 of 26 APPE NDIX. D TECH. DESIGN SUMMARY As Revised ____ _ I I SECTION IX APPENDIX D -TECHNICAL DESIGN SUMMARY Part 4 -Drainage Conce12t and Design Parameters I 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? Cl 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 '==J Yes If "yes" identify location(s), describe change(s), and justification: Are flumes or conduit to discharge into culvert barrel(s)? I ... l No D Yes If yes, identify location(s) and provide justification: "O Are flumes or conduit to discharge into or near surfaced approaches to culvert ends? (l) I. l No L_J Yes If "yes" identify location(s), describe outfall design treatment(s): ::i c c 0 ~ ~ (l) 2 ::i Is scour/erosion protection provided to ensure long term stability of culvert structural u components, and surfacing at culvert ends? L::J Yes L.J 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? L_] Yes D 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? D No Yes If "yes" describe location(s) and mitigation measures Are all culvert designs and materials in compliance with 8-CS Tech. Specifications? ...Li.. Yes I ; No If not, explain in Special Design Section of this Part. STORMWATER DESIGN GUIDELINES Effective February 2007 Page 21 of 26 APPENDIX. D TECH. DESIGN SUMMARY As Revised ____ _ SECTION IX APPENDIX D -TECHNICAL DESIGN SUMMARY Part 4 -Drainage ConceQt and Design Parameters l 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? D No D Yes If "yes" provide the following information. Name(s) and functional classification of the roadway(s)? What drainage way(s) is to be crossed? ~ Q) O"J "O ·.:::: a:J A full report supporting all aspects of the proposed bridge(s) (structural, geotechnical, hydrologic, and hydraulic factors) must accompany this summary report. provided? D_ Yes CJ No If "no" explain: Is the report Is a Stormwater Provide a general description of planned techniques: .£ Pollution Prevention ro Plan (SW3P) :::J a established for ~ project construction? Q) -ro I J No 0 Yes s Special Designs -Non-Traditional Methods Are any non-traditional methods (aquatic echosystems, wetland-type detention, natural stream re~tion, BMPs for water quality, etc.) proposed for any aspect of subject property project? · No L I 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? n Yes ri No If "no" explain: STORMWATE R DESIGN GU IDELINES Effective February 2007 !V/f Page 22 of 26 APPENDI X. D TECH. DESIGN SUMMARY As Revised ____ _ I SECTION IX APPENDIX D -TECHNICAL DESIGN SUMMARY Part 4 -Drainage Conce12t and Design Parameters I 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. I _] Detention elements .CJ. Drain system elements I::l. Channel features Culvert features Swales Ditches Inlets Outfalls I _d J Valley gutters _.D_ 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) fUon e 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) 2) 3) 4) 5) Design Parameters Hydrology / Is a map(s) showing all Design Drainage Areas provided? 10. Yes I i No Briefly summarize the range of applications made of the Ratio~Formula: /. f'J1.m e -!~EC -/-/ rn 5 Wt/ f V5('d Or Ju;J/.., oj' '<- v rnPc/e1v What is the size and location of largest Design Drainage Area to which the Rational Formula has been applied? (ltPflf?._ acres STORMWATER DESIGN GUIDELINES Effective February 2007 Location (or identifier) Page 23 of 26 APPENDIX. D TECH. DE SIGN SUMMARY As Revised ___ _ I f SECTION IX APPENDIX D -TECHNICAL DESIGN SUMMARY Part 4 -Drainage ConceQt and Design Parameters I Continued (Page 4.15) Design Parameters (continued) Hydrology (continued) In making deter ations for time of concentration, was segment analysis used? CJ No ] Yes In approximately what percent of Design Drainage Areas? {tDO % As to intensity-duration-frequency and rain depth criteria for dr ming runoff flows , were any criteria other than those provided in these Guidelines used? . No I I 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 too /00 Detention facilities outlet and conveyance structure(s) 2 /0, 2 S-5.? /VO ';( I 0 2. 5, !;.!., ' Detention facilities: volume when outlet plugged JOO /DO Cu lverts serving private drives or streets Culverts serving public roadways Bridges: provide in bridge report. r1 Hydraulics ,... . I 1 /\ . /l.P fr-:J,•:f What is the range of design flow velocities as outlined below?____..-UuT 1 .. I ) Design flow velocities; Highest (feet per second) Lowest (feet per second) Streets-and Stonn Dcaio Systems Roughness coefficients used: For conduit type(s) ltfJPE STORMWATER DESIGN GUIDELINES Effective February 2007 Gutters 90rrd< Culverts Swales Channels tJ) ti /7. 40 \ fl)/) (/)Ii fl)/) , - 5<./171"-J Provide the ~ry information outlined below: For street gutters: n :: Coefficients: o, 013 Page 24 of 26 APPENDIX D TECH. DESIGN SUMMARY As Revised ____ _ I() .:J SECTION IX APPENDIX D -TECHNICAL DESIGN SUMMARY Pa rt 4 -Drai nage Conce12t and Design Parameters I 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? '=--_]No L J Yes Head and friction losses D No ··-···-~ Yes Explain any "yes" answer: ruf+ In conduit is velocity generally increased in the downstream direction? 0 Yes LJ No Are elevation drops provided at inlets, manholes , and junction boxes? Yes No Explain any "no" answers: llJ/)- Are hydraulic grade lines calculated and shown for design storm? L_J Yes .DNo For 100-year flow conditions? Yes L]No Explain any "no" answers: fl) ff What tailwater condition.s were assumed at outfall point(s) of the sJ.rm_lrain system? Identify each location and explain: 1)55<..1/ne J-0 la'! D ct/ w ~fe-r 4f oui/:i!/ />'ii(/· Open Channels If a HEC analysis is utilized, does it follow Sec Vl.F.5.a? LJ Yes r 1 No Outside of straight sections, is flow regime within limits of sub-critical flow? .D Yes D 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? Entrance, friction and exit losses: Bridges Provide all in bridge report STORMWATER DESIGN GUIDELINES Effective February 2007 Page 25 of 26 APPENDIX. D TECH. DESIGN SUMMARY As Revised ____ _ SECTION IX APPENDIX D -TECHNICAL DESIGN SUMMARY Part 4 -Drainage Concept and Design 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 /-/ E C --/-J /YJ :; 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 Ill, 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 Desi n Summar Draina e Re ort b si nin and sealin 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 propert and permits required by any and all state and federal regulatory agenci drainage improvements have been issued or fall under applicable gen Licensed Professional Engineer State of Tex as PE No._~G~£~q~z~3~_ STORMWATER DESIGN GUIDELINES Effective February 2007 Page 26 of 26 (Affix APPENDIX. D TECH. DESIGN SUMMARY As Revised ____ _