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HomeMy WebLinkAboutDrainage ReportMarch 1, 2012 Josh Norton, P.E. Assistant City Engineer Planning and Development Services City of College Station P 0 Box 9960 College Station, TX 77842 Planning • Engineering • Management RE: Drainage Report Executive Summary Baumann Office Building Dear Mr. Norton, Bleyl & Associates Transmitted under this cover is Appendix D Technical Design Summary for the referenced project. The submittal date for this project is March 05, 2012. The following is the engineer, developer, and owner contact information. Engineer Information: Sam Vernon Bleyl & Associates 1722 Broadmoor, Suite 210 Bryan, Texas 77802 (979)- 268 -1125 Developer Information: Paul Baumann 1016 Muirfield Village College Station, Texas 77845 (979)- 571 -8425 Owner Information: Wilfred P. Jacinto and Julie C. Herrera Jacinto 4189 Bentwood Dr. College Station, Texas 77845 Currently there is a Site Plan and Development Permit Applications are being processed. The case number for this project is 12- 00500014. The project will be a single - phased development of a .404 acre tract currently zoned as "C2 ". The property will be developed to contain a 3,750 square foot office building along with necessary parking. This project is located at 108 Morgans Lane, approximately 450 feet northeast of the intersection of Morgans Lane and South Texas Avenue in College Station, Texas and is located entirely within the City of College Station city limits. It is located in the Bee Creek Watershed and neither straddles a watershed nor a basin divide. The property is gently sloped from west to east and the existing land cover consists mostly of Bermuda grass with a tree line located on the east side of the property. There are no storm 1722 Broadmoor Suite 210 Bryan, Texas 77802 Tex. Reg. No. F -678 Bryan Austin Conroe (979) 268 -1125 (512) 328 -7878 (936) 441 -7833 (979) 260 -3849 Fax (512) 328 -7884 Fax (936) 760 -3833 Fax drains or ditches located on the property. Runoff from this property is primarily sheet flow and shallow concentrated flow near the northeastern corner. Section II.C.3.b enumerates conditions where detention is not required. Because of condition 3, less than one acre in size, my calculations and design precautions listed below, I certify the following statement without qualifications: "I have conducted a topographic review and field investigation of the existing and proposed flow patterns for storm water runoff from Lot 16B revised of the Lake View Acres to the main stem of Bee Creek. At build -out conditions allowable by zoning, restrictive covenant, or plat note, the storm water flows from the subject subdivision or site project will not cause any increase in flooding conditions to the interior of existing building structures, including basement areas, for storms of magnitude up through the 100 -year event." The pre - developed flow is estimated to be 1.93 cfs based on the Rational Method. Using same method, the post- condition flow is estimated at 3.80 cfs. Runoff between the parking lot and the property line along the north, east, and west sides will still leave the site under a sheet flow condition. Runoff collected in the parking lot will exit the pavement through an eighteen inch wide curb opening on the northeast corner of the parking lot. Erosion protection at this location will be 6" — 12" rip rap. The curb opening was sized at 18" to allow water to be released from the parking area at 1.5 cfs. The parking lot will also provide 345 cubic feet of storage during an intense storm event while not ponding over 6" of water. No portion of the property is the floodplains as shown the FEMA rate map number, 4800830144C. The Developer is aware that his obligation for the coordination and permitting of all stormwater matters during construction. We are not aware of any conditions beyond this that may pertain to this project. I have included a copy of my calculations and drainage are maps for your review along with Appendix D Technical Drainage Summary for your review. Please do not hesitate to contact me with any questions or requests for further information. cerely, am J. 3 non Project Engineer Attachments S' g �e. OF od,, .... -rq it N V: v :0N , 1 1°1% :13T-53/-:: 1222J I REV _ DATE BY PPP COMMENT I PREPARED 10. MA rarp0'AVM COMER OM 471 FOR !WON. 10 M. -son 60ME: DATE: wen 2012 DRANK BY: 0011 PROJECT MANAGER: 9111 J. HAN011. P.E. BAUMANN TRACT B A Bleyl & Associates A Project Engineering & Management 1722 BROPOMOOR, STE. 210 2251 N. LOOP 336 W BRYAN. TEXAS 77802 CONROE, TEXAS 77304 (979) 268 -1125 PHONE (938) 441 -7833 PHONE (979) 260 -3849 FAX (936) 760 -3833 FAX TEXAS BOARD of PROFESSIONAL ENGINEERS: F -678 ATION\ENG\DRANAGE\DRNNAGE—PRE ley' & Associate 2 2:06 PM Rational Flowrate oot SJo 01.'0 £9'1. (L - 0 algel) (j4N!) - 1 49'I L 4911 00 SJo O 1.'0 9L' L (1 algal) os l O4N!) 1 91'11. 91.'LL sz 800 99'L (L - 0 algal) Sz l G4N!) 98'6 98'6 oi sjo L0'0 92'1. (L - 0 algal) 0L l WM) £9'9 £9'8 zo slo 90'0 66'0 (L - 0 algel) UqN!) ££'9 ££'9 J < O (;aayspeaids of wail) NOLLVNI.N30NO0 dO 30111 u!w 00'01. 00'0 L Drainage Areas 1v101 vo I 600'0 L9VO „o„ 31ISOdWOO 01.4'0 01.4'0 sno!aadw! 96'0 (son Ja ;ua0 6u!ddoyg) 1e!3JaW WOO 48'0 1 (sado!g 06eJany) panaldw!u0 aJn3sed 64'0 1 LZ0'0 £8£'0 (sado!g 96eJany) PaPooM 6£'0 (sado!S a6eJany 'AIL - N4 = az!S lol) !e! ;uap!saa A!!we3 a!6u!g 49'0 V3LIy 1VIOl DV 1.20'0 £8£'0 ValV 3OVNIHNO a Z L-`da K«<I I REV DATE BY APP COMMENT PREPARED FOR M' FAIL IMMIX 014 mum. MLIAYE ( -MS SOµE: Damn 2012 DRAIN DR ROH PROJECT WAVER: 5X1 J. 90608*. PE N CD Z 0 W Z 0 z LA 0 %!a%%Affiza BAUMANN TRACT B Bleyl & Associates & � A Project Engineering & Management 1722 BROAOMOOR, STE. 210 BRYAN. TEXAS 77802 (979) 266 -1125 PHONE (979) 280 -3649 FAX 2251 N. LOOP 336 W CONROE, TEXAS 77304 (936) 441 -7833 PHONE (936) 760 -3633 FAX TEXAS BOARD of PNVI[s.,10NAL ENGINEERS: F -678 IMPERMEABLE AREAS PERMEABLE AREAS Rational Flowrate 001 I 08'£ (L - O algal) 0011 Witt!) 49' I• l os I Sj 49£ (l - O algal) °S l WN!) 91'14 sz si.1 ZZ'£ (l - O algal) Sz I ( ' 4 J ° ! ) 98 01 SP z8'z (l - O algal) °1 I (RIM!) £98 z I S 90Z (L - O 0 19 13 1) z 1 (i4/u!) 88'9 Q I— r NOIiVH1N3ONOO 3O 301I1 u!w 00 01. Drainage Areas -ylol I Vo 9Z£'0 . 311SOdINOO L08'0 sno!AJedwl 96'0 Z6Z'O (sa ;!S Ja ;uaD 6u!ddo4S) !e!3JawwoO 49'0 (sado!S a6eJany) panadw!un aln;sed I 1 . 4 ' 0 I ZLVO (sado!S a6eJany 'uog!puo0 poop) seeJv sseJ0 6£'0 (sedo!S a6eJany ')IL - Is = az!S 1 !eguap!saa A!!we3 aft/IS 49 I V321y 1V1O1 I DV 404'0 y321y 30VNIV U 0 o-va Baumann Tract Part 2 — Project Administration Start (Page 2.1) Engineering and Design Professionals Information Engineering Firm Name and Address: Bleyl & Associates 1722 Broadmoor, Suite 210 Bryan, Texas 77802 Tex. Req. No. F -678 Jurisdiction City: Bryan X College Station Date of Submittal: March 5, 2012 Lead Engineer's Name and Contact Info.(phone, e-mail, fax): Sam A. Vernon, P.E. 268 -1125, svernon @bleylengineering.com, 260 -3849 Other: Supporting Engineering / Consulting Firm(s): Other contacts: Developer / Owner / Applicant Information Developer / Applicant Name and Address: Mr. Paul Baumann 1016 Muirfield Village College Station, Texas 77845 Phone and e-mail: (979) 571 - 8425 baumann@suddenlink.net Property Owner(s) if not Developer / Applicant (& address): Wilfred P Jacinto & Julie C Herrera Jacinto 4189 Bentwood Dr, C.S., TX 77845 Phone and e-mail: Project Identification Development Name: Baumann Off ice Building Is subject property a site project, a single -phase subdivision, or part of a multi -phase subdivision? Site Project If multi - phase, subject property is phase of . Legal description of subject property (phase) or Project Area: (see Section II, Paragraph B -3a) 108 Morgans Lane, C.S., TX 77845 Lot 16 -B, Lake View Acres 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. N/A General Location of Project Area, or subject property (phase): 108 Morgans Lane. Approximately 450 feet northeast of the intersection of Morgans Lane and South Texas Avenue in College Station, Texas. In City Limits? Bryan: 0 acres. Extraterritorial Jurisdiction (acreage): Bryan: 0 College Station: 0 College Station: 0 .404 acres. Acreage Outside ETJ: 0 SECTION IX APPENDIX D - TECHNICAL DESIGN SUMMARY STORMWATER DESIGN GUIDELINES Page 3 of 26 APPENDIX. D: TECH. DESIGN SUMMARY Effective February 2007 As Revised February 2009 Part 2 — Project Administration Continued (page 2.2) Project Identification (cont Roadways abutting or within Project Area or subject property: Morgan's Lane Abutting tracts, platted land, or built developments: Lot 15A Lakeview Acres Lot 16A Lakeview Acres Lot 16C Lakeview Acres Named Regulatory Watercourse(s) & Watershed(s): Bee Creek Watershed Tributary Basin(s): Plat Information For Project or Subject Property (or Phase) Preliminary Plat File #: Final Plat File #: Date: 8-11-1994 Name: Status and VoI /Pg: V 2182 P 34 If two plats, second name: File #: Status: Date: Zoning Information For Project or Subject Property (or Phase) Zoning Type: C - 2 Existing or Proposed? Existing 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): None Participants: N/A Preliminary Report Required? Submittal Date 1-18 -2012 Review Date 2-21 -2012 Review Comments Addressed? Yes X 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. none SECTION IX APPENDIX D - TECHNICAL DESIGN SUMMARY STORMWATER DESIGN GUIDELINES Page 4 of 26 APPENDIX. D: TECH. DESIGN SUMMARY Effective February 2007 As Revised February 2009 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. Coordination With Other Departments of Jurisdiction City (Bryan or College Station) Dept. Contact: Date: Subject: Coordination With Non jurisdiction City Needed? Yes No X Summarize need(s) & actions taken (include contacts & dates): Coordination with Brazos County Needed? Yes No X Summarize need(s) & actions taken (include contacts & dates): Coordination with TxDOT Needed? Yes No X Summarize need(s) & actions taken (include contacts & dates): Coordination with TAMUS Needed? Yes No X Summarize need(s) & actions taken (include contacts & dates): 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 ? Status of Actions (include dates) US Army Crops of Engineers No Yes X US Environmental Protection Agency No Yes X Texas Commission on Environmental Quality No Yes X Brazos River Authority No Yes X SECTION IX APPENDIX D - TECHNICAL DESIGN SUMMARY STORMWATER DESIGN GUIDELINES Page 5 of 26 APPENDIX. D: TECH. DESIGN SUMMARY Effective February 2007 As Revised February 2009 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 Development Project (select all applicable) Redevelopment of one platted lot, or two or more adjoining platted lots. X Building on a single platted lot of undeveloped land. Building on two or more platted adjoining lots of undeveloped land. 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 Development Project Construction of streets and utilities to serve one or more platted lots. Construction of streets and utilities to serve one or more proposed lots on lands represented by pending plats. Describe Nature and Size of Proposed Site proiects: building use(s), approximate floor space, impervious cover ratio. Subdivisions: number of lots by general type of use, linear feet of streets and drainage easements or ROW. Construction of a 3750 square foot office building Impervious cover ratio is 0.70 Project Is any work planned on land that is not platted If yes, explain: or on land for which platting is not pending? X No Yes FEMA Floodplains Is any part of subject property abutting a Named Regulatory Watercourse (Section II, Paragraph B1) or a tributary thereof? No X Yes Is any part of subject property in floodplain area of a FEMA - regulated watercourse? No X Yes Rate Map 4800830144C Encroachment(s) into Floodplain areas planned? No X Encroachment purpose(s): Building site(s) Road crossing(s) Utility crossing(s) Other (explain): 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. N/A SECTION IX APPENDIX D - TECHNICAL DESIGN SUMMARY STORMWATER DESIGN GUIDELINES Page 6 of 26 APPENDIX. D: TECH. DESIGN SUMMARY Effective February 2007 As Revised February 2009 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 earlier study? management plan for the property in substantial Yes No If not, explain how conformance with the it differs. No If subject property plan for the property is not part of multi -phase project, describe stormwater management 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 Describe them (include approximate size, volume, outfall, model, etc). runoff? X No Yes Any known drainage or flooding problems in areas near subject property? Identify: X No Yes Based (see Table on location of B -1 in Appendix Detention is required. study property in a watershed, is Type 1 Detention (flood control) needed? B) Need must be evaluated. X Detention not required. If the need for Type 1 Detention must be evaluated: What decision has been reached? By whom? How was determination made? SECTION IX APPENDIX D - TECHNICAL DESIGN SUMMARY STORMWATER DESIGN GUIDELINES Page 7 of 26 APPENDIX. D: TECH. DESIGN SUMMARY Effective February 2007 As Revised February 2009 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? describe splits below. In Part 4 describe design concept X No Yes If yes, 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? Size(s) of area(s) in acres: 1) 2) 3) X No Yes 4) Flow Characteristics (each instance) (overland sheet, shallow concentrated, recognizable Watercourse or tributary); concentrated section(s), small creek (non - regulatory), regulatory N/A Flow determination: Outline hydrologic methods and assumptions: N/A Does storm runoff drain from public easements or ROW X No Yes If yes, describe facilities in easement onto or across subject property? or ROW: Are changes in runoff characteristics subject to change in future? Explain None are anticipated Conveyance Pathways (Section II, Paragraph C2) Must runoff from study property drain across lower properties before reaching a Regulatory Watercourse or tributary? No X Yes Describe length and characteristics of each conveyance pathway(s). Include ownership of property(ies). Runoff from property drains across Lakeview Acres Lot 15A to reach an un -named tributary of Bee Creek. The drainage is characterized by sheet flow, with some shallow concentrated flow along Morgans LN. Lot 15A is owned by Alvin & Patricia Larke, 120 Morgans LN, C.S., Texas 77845 -5036 SECTION IX APPENDIX D - TECHNICAL DESIGN SUMMARY STORMWATER DESIGN GUIDELINES Page 8 of 26 APPENDIX. D: TECH. DESIGN SUMMARY Effective February 2007 As Revised February 2009 Part 3 — Property Characteristics Continued (Page 3.4) Hydrolo Attributes of Subject Property (or Phase) (continued) Conveyance Pathways (continued) Do drainage easements exist for part of pathway(s)? X No any If yes, for what part of length? % Created by? plat, or instrument. If instrument(s), describe their provisions. Yes Pathway Areas Where runoff must cross lower properties, describe characteristics of abutting lower property(ies). (Existing watercourses? Easement or Consent aquired ?) The residential property is mostly cleared with a uniform slope of 2% to the east. There are no existing watercourses on the property Nearby Drainage Facilities Describe any built or improved drainage facilities existing near the property (culverts, bridges, lined channels, buried conduit, swales, detention ponds, etc). There is a buried 18" RCP culvert downstream of the proposed development on Morgans LN. The pipe no longer carries any flow Do any of design? these have hydrologic or hydraulic influence on X No Yes If yes, explain: proposed stormwater SECTION IX STORMWATER DESIGN GUIDELINES Page 9 of 26 APPENDIX. D: TECH. DESIGN SUMMARY As Revised February 2009 APPENDIX D - TECHNICAL DESIGN SUMMARY Effective February 2007 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. N/A Discharge(s) To Lower Property(ies) (Section II, Paragraph El) Does project include drainage features (existing or future) proposed to become public via platting? X No Yes Separate Instrument? X No Yes Per Guidelines reference above, how will runoff be discharged to neighboring property(ies)? Establishing Easements (Scenario 1) X Pre - development Release (Scenario 2) 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 # ) Six (6) 1 foot wide slots are proposed at the east corner of the parking lot. This design will breakup the concen- trated flow from the parking lot, as well as detaining the increased peak flow. 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 owner(s) of receiving property(ies)? X No Yes Explain and provide documentation. SECTION IX STORMWATER DESIGN GUIDELINES Effective February 2007 APPENDIX D - TECHNICAL DESIGN SUMMARY Page 10 of 26 APPENDIX. D: TECH. DESIGN SUMMARY As Revised February 2009 Part 4 — Drainage Concept and Design Parameters Continued (Page 4.2) Stormw Management Concept (continued) Within Project Area Of Multi -Phase Project N/A Will project result in shifting runoff between Basins or between Watersheds? No Identify gaining Basins or Watersheds and acres shifting: What design and mitigation is used to compensate for increased runoff from gaining basin or watershed? Yes How will runoff from Project Area be mitigated to pre- development conditions? Select any or all of 1, 2, and /or 3, and explain below. 1. With facility(ies) involving other development projects. 2 Establishing features to serve overall Project Area. 3. On phase (or site) project basis within Project Area. 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) project: 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)? Are other Best Management Practices for reducing stormwater pollutants proposed? No Yes Summarize type of BMP and extent of use: If design of any runoff - handling facilities deviate from provisions of B -CS Technical 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 SECTION IX STORMWATER DESIGN GUIDELINES Effective February 2007 APPENDIX D - TECHNICAL DESIGN SUMMARY Page 11 of 26 APPENDIX. D: TECH. DESIGN SUMMARY As Revised February 2009 Part 4 — Drainage Concept and Design Parameters Continued (Page 4.3) Stormwater Management Concept (continued) Within Project Area Of Multi -Phase Project (continued) N/A 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): N/A Identify whether each of the types of drainage features listed below are included, extent of use, and general characteristics. Typical shape? Surfaces? ditches use Yes Steepest side slopes: Usual front s opes: Usual back slopes: Flow line slopes: least Typica distance from travelway: (Attached Exhibit # ) typical greatest 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: eets with ci jutter Are valley gutters proposed to cross any street away from an intersection? No Yes Explain: (number of locations ?) SECTION IX STORMWATER DESIGN GUIDELINES Effective February 2007 APPENDIX D - TECHNICAL DESIGN SUMMARY Page 12 of 26 APPENDIX. D: TECH. DESIGN SUMMARY As Revised February 2009 Part 4 — Drainage Concept and Design Parameters Continued (Page 4.4) Stormwater Management Concept (continued) Within Or Serving Subject Property (Phase, or Site) (continued) Are streets with curb and gutter used? (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. Will inlet size and placement prevent exceeding allowable water spread for 10 -year design storm throughout site (or phase)? Yes No If no, explain. Sag curves: Are inlets placed at low points? Yes No Are inlets and conduit sized to prevent 100 -year stormflow from ponding at greater than 24 inches? Yes No Explain "no" answers. Will 100 -yr stormflow be contained in combination of ROW and buried conduit on 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. Is storm drain system used? �C No Yes Are any 12 -inch laterals used? No Yes Identify length(s) and where used. Pipe runs between system access points (feet): Typical Longest Are junction boxes used at each bend? Yes No If not, explain where and why. Are downstream soffits at or below upstream soffits? Yes No If not, explain where and why: Least amount that hydraulic grade line is below gutter line (system- wide): SECTION IX STORMWATER DESIGN GUIDELINES Effective February 2007 APPENDIX D - TECHNICAL DESIGN SUMMARY Page 13 of 26 APPENDIX. D: TECH. DESIGN SUMMARY As Revised February 2009 Part 4 — Drainage Concept and Design Parameters Continued (Page 4.5) Stormwater Management Concept (continued) Within Or Serving Subject Property (Phase, or Site) (continued) Storm drain system (continued) (on separate sheet provide same info. for more instances) (s)IlejjnQ Describe watercourse(s), or system(s) receiving system discharge(s) below (include design discharge velocity, and angle between converging flow lines). 1) Watercourse (or system), velocity, and angle? 2) Watercourse (or system), velocity, and angle? 3) Watercourse (or system), velocity, and angle? For each outfall above, what measures are taken to prevent erosion or scour of receiving and all facilities at juncture? 1) 2) 3) Are swales used to drain streets? 5c No Yes 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): Flow line slopes (minimum and maximum): Outfall characteristics for each (velocity, convergent angle, & end treatment). Will 100 -year design storm runoff be contained within easement(s) or platted drainage ROW in all instances? Yes No If "no" explain: SECTION IX STORMWATER DESIGN GUIDELINES Effective February 2007 APPENDIX D - TECHNICAL DESIGN SUMMARY Page 14 of 26 APPENDIX. D: TECH. DESIGN SUMMARY As Revised February 2009 Part 4 — Drainage Concept and Design Parameters Continued (Page 4.6) Stormwater Management Concept (continued) Within Or Serving Subject Property (Phase, or Site) (continued) Roadside Ditches Are roadside ditches used? X No Yes If so, provide the following: ? Yes No Is 25 -year flow contained with 6 inches of freeboard throughout Are top of banks separated from road shoulders 2 feet or more? Are all ditch sections trapezoidal and at least 1.5 feet deep? Yes No Yes No For any "no" answers provide location(s) and explain: No roadside ditches are used (on separate sheet provide same information for any additional instances) If conduit is beneath a swale, provide the following information (each instance). Instance 1 Describe general location, approximate length: Is 100 -year design flow contained in conduit/swale combination? If "no" explain: Yes No Space for 100 -year storm flow? ROW Easement Width Swale Surface type, minimum Conduit Type and size, minimum and maximum and maximum slopes: slopes, design storm: Inlets Describe how conduit is loaded (from streets /storm drains, inlets by type): Access Describe how maintenance access is provided (to swale, into conduit): Instance 2 Describe general location, approximate length: Is 100 -year design flow contained in conduit/swale combination? If "no" explain: Yes No Space for 100 -year storm flow? ROW Easement Width Swale Surface type, minimum Conduit Type and size, minimum and maximum and maximum slopes: slopes, design storm: Inlets Describe how conduit is loaded (from streets /storm drains, inlets by type): Access Describe how maintenance access is provided (to swale, into conduit): SECTION IX STORMWATER DESIGN GUIDELINES Effective February 2007 APPENDIX D - TECHNICAL DESIGN SUMMARY Page 15 of 26 APPENDIX. D: TECH. DESIGN SUMMARY As Revised February 2009 Part 4 — Drainage Concept and Design Parameters Continued (Page 4.7) Stormwater Management Concept (continued) Within Or Serving Subject Property (Phase, or Site) (continued) Will swales without buried conduit receive runoff from public ROW or easements? 5C No Yes. Explain If "yes" provide the following information for each instance: Instance 1 Describe general location, approximate length, surfacing: Is 100 -year design flow contained in swale? Yes No Is swale wholly within drainage ROW? Yes No Explain "no" answers: Access Describe how maintenance access is provide: Instance 2 Describe general location, approximate length, surfacing: Is 100 -year design flow contained in swale? Yes No Is swale wholly within drainage ROW? Yes No Explain "no" answers: 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. Channel improvements proposed? No Yes Explain "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. Will design replicate natural channel? Yes No If "no ", for each instance describe section shape & area, flow line slope (min. & max.), surfaces, and 100 -year design flow, and amount of freeboard: Instance 1: Instance 2: Instance 3: SECTION IX STORMWATER DESIGN GUIDELINES Effective February 2007 APPENDIX D - TECHNICAL DESIGN SUMMARY Page 16 of 26 APPENDIX. D: TECH. DESIGN SUMMARY As Revised February 2009 Part 4 — Drainage Concept and Design Parameters Continued (Page 4.8) Stormwater Management Concept (continued) Within Or Serving Subject Property (Phase, or Site) (continued) Channel Improvements (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. Watercourses (and tributaries): Aside from fringe changes, are Regulatory Explain below. Watercourses proposed to be altered? No Yes Submit full report describing proposed changes to Regulatory existing and proposed section size and shape, surfaces, alignment, length affected, and capacity, and provide full documentation and data. Is full report submitted? Yes No Watercourses. Address flow line changes, of analysis procedures If "no" explain: All 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 Yes No If not, identify location(s) and explain: maintenance space? SECTION IX STORMWATER DESIGN GUIDELINES Effective February 2007 APPENDIX D - TECHNICAL DESIGN SUMMARY Page 17 of 26 APPENDIX. D: TECH. DESIGN SUMMARY As Revised February 2009 Part 4 — Drainage Concept and Design Parameters Continued (Page 4.9) St ormwater 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: Faci ity 1 Faci ity 2 Acres served & design volume + 10% 100 -yr volume: free flow & plugged Design discharge (10 yr & 25 yr) Spillway crest at 100 -yr WSE? Berms 6 inches above plugged WSE? Explain any "no" answers: yes no yes no yes no yes no For each facility what is 25 -yr design Q, and design of outlet structure? Facility 1: 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: For each, what is velocity of 25 -yr design discharge at outlet? & at spillway? Facility 1: & Facility 2: & Are energy dissipation measures used? No Yes Describe type and location: For each, is spillway surface treatment other than concrete? Yes or no, and describe: 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: SECTION IX STORMWATER DESIGN GUIDELINES Effective February 2007 APPENDIX D - TECHNICAL DESIGN SUMMARY Page 18 of 26 APPENDIX. D: TECH. DESIGN SUMMARY As Revised February 2009 Part 4 — Drainage Concept and Design Parameters Continued (Page 4.10) Stormwater Management Concept (continued Within Or Serving Subject Property (Phase, or Site) (continued) Detention Facilities (continued) Do structures comply with B -CS Specifications? Yes or no, and explain if "no ": Facility 1; Facility 2: For 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? Are culverts used at private crossings? 5c No Yes 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: Are culverts parallel to public roadway alignment? Yes No Explain: Creeks at Private Drives: Do private driveways, drives, or streets cross drainage ways that serve Above - Project areas or are in public easements/ ROW? No Yes If "yes" provide information below. How many instances? Describe location and provide information below. Location 1: 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. SECTION IX STORMWATER DESIGN GUIDELINES Effective February 2007 APPENDIX D - TECHNICAL DESIGN SUMMARY Page 19 of 26 APPENDIX. D: TECH. DESIGN SUMMARY As Revised February 2009 Part 4 — Drainage Concept and Design Parameters Continued (Page 4.11) Stormwater Management Concept (continued) Within Or Serving Subject Property (Phase, or Site) (continued) (for more instances of any type describe location and same information on separate sheet) Named Regulatory Watercourses (& Tributaries): Are culverts proposed on these assumptions, support proposed ", explain: facilities? No Yes, then provide full report documenting that If "no criteria, analysis, computer programs, and study findings design(s). Is report provided? Yes No Arterial or Maior Collector Streets: Will culverts serve these types of roadways? For each identify the No Yes How many instances? location and provide the information below. Instance 1: Instance 2: Instance 3: Yes or No for the 100 -year design flow: 1 2 3 Headwater WSE 1 foot below lowest curb top? Spread of headwater within ROW or easement? Is velocity limited per conditions (Table C -11)? Explain any "no" answer(s): Minor Collector or Local Streets: Will culverts serve these types for of streets? each identify the No Yes How many instances? location and provide the information below: Instance 1: Instance 2: Instance 3: For each instance enter value, or "yes" / "no" for: 1 2 3 Design yr. headwater WSE 1 ft. below curb top? 100 -yr. max. depth at street crown 2 feet or less? Product of velocity (fps) & depth at crown (ft) _ ? Is velocity limited per conditions (Table C -11)? Limit of down stream analysis (feet)? Explain any "no" answers: SECTION IX STORMWATER DESIGN GUIDELINES Effective February 2007 APPENDIX D - TECHNICAL DESIGN SUMMARY Page 20 of 26 APPENDIX. D: TECH. DESIGN SUMMARY As Revised February 2009 Part 4 — Drainage Concept and Design Parameters Continued (Page 4.12) Stormwater Management Concept (continued) Within Or Serving Subject Property (Phase, or Site) (continued) z Culverts (continued) All Proposed Culverts: For all proposed culvert facilities (except driveway /roadside boxes. ditch intersects) provide information requested in next eight 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 approaches thereto? No Yes If "yes" identify location(s), culvert and surfaced 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 No Yes If "yes" identify location(s), describe to culvert ends? outfall design treatment(s): Is scour /erosion protection provided to ensure long term stability of culvert structural 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 drainage easements/ ROW? Yes No if not, why in street ROW, and /or not? Do appreciable hydraulic effects of any culvert extend downstream neighboring land(s) not encompassed in subject property? "yes" describe location(s) and mitigation measures: or upstream to No Yes If Are all culvert designs and materials in compliance with B -CS Yes No If not, explain in Special Design Section Tech. Specifications? of this Part. SECTION IX STORMWATER DESIGN GUIDELINES Effective February 2007 APPENDIX D - TECHNICAL DESIGN SUMMARY Page 21 of 26 APPENDIX. D: TECH. DESIGN SUMMARY As Revised February 2009 Part 4 - Drainage Concept and Design Parameters Continued (Page 4.13) Stormw Management Concept (continued) Within Or Serving Subject Property (Phase, or Site) (continued) Bridge(s) Is a bridge included in If "yes" provide the following plans for subject property project? X No Yes information. Name(s) and functional classification of the roadway(s)? What drainage way(s) is to be crossed? A full report supporting all aspects of the proposed bridge(s) hydrologic, and hydraulic factors) must accompany this summary provided? Yes No If "no" explain: (structural, geotechnical, report. Is the report Water Quality Is a Stormwater Pollution Prevention Plan (SW3P) established for project construction? No X Yes Provide a general description of planned techniques: Provide Sediment Control Fence at Project perimeter to control erosion of disturbed soil during construction Special Designs — Non - Traditional Methods Are any non - traditional methods replication, BMPs for water quality, X No Yes If `yes" list (aquatic echosystems, wetland -type detention, natural stream etc.) proposed for any aspect of subject property project? general type and location below. Provide full report about the proposed expected benefits. Report must be compromised, and that maintenance solution(s). Is report provided? special design(s) including rationale substantiate that stormwater management cost will not exceed those of Yes No If "no" explain: for use and objectives will not traditional design SECTION IX STORMWATER DESIGN GUIDELINES Effective February 2007 APPENDIX D - TECHNICAL DESIGN SUMMARY Page 22 of 26 APPENDIX. D: TECH. DESIGN SUMMARY As Revised February 2009 Part 4 — Drainage Concept and Design Parameters Continued (Page 4.14) Stormwater Management Concept (continued) Within Or Serving Subject Property (Phase, or Site) (continued) Special Designs — Deviation From B -CS Technical Specifications If any design(s) or material(s) of traditional runoff - handling facilities deviate from provisions of B -CS Technical Specifications, check type facility(ies) and explain by specific detail element. Detention elements Drain system elements Channel features Culvert features Swales Ditches Inlets Outfalls Valley gutters Bridges (explain in bridge report) In table below briefly identify specific element, justification for deviation(s). Specific Detail Element Justification for Deviation (attach additional sheets if needed) 1) 2) 3) 4) 5) Have elements been coordinated with the City Engineer or her /his designee? For each item above provide "yes" or "no ", action date, and staff name: 1) 2) 3) 4) 5) Design Parameters Hydrology Is a map(s) showing all Design Drainage Areas provided? X Yes No Briefly summarize the range of applications made of the Rational Formula: Rational Method was used for the entire 0.404 Acre site What is the size and location of largest has been applied? 0 .404 acres Design Drainage Area to which the Rational Formula Location (or identifier): Entire Site SECTION IX STORMWATER DESIGN GUIDELINES Page 23 of 26 APPENDIX. D: TECH. DESIGN SUMMARY As Revised February 2009 APPENDIX D - TECHNICAL DESIGN SUMMARY Effective February 2007 Part 4 — Drainage Concept and Design Parameters Continued (Page 4.15) Design Parameters (conti Hydrology (continued) In making determinations for time of concentration, was segment analysis used? X No Yes In approximately what percent of Design Drainage Areas? ok As to intensity- duration - frequency and rain depth criteria for criteria other than those provided in these Guidelines used? identify type of data, source(s), and where applied: determining X No runoff flows, Yes were any If "yes" 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 N/A N/A Storm drain system for local streets N/A N/A Open channels N/A N/A Swale /buried conduit combination in lieu of channel N/A N/A Swales N/A N/A Roadside ditches and culverts serving them N/A N/A Detention facilities: spillway crest and its outfall N/A N/A Detention facilities: outlet and conveyance structure(s) N/A N/A Detention facilities: volume when outlet plugged N/A N/A Culverts serving private drives or streets N/A N/A Culverts serving public roadways N/A N/A Bridges: provide in bridge report. N/A N/A Hydraulics What is the range of design flow velocities as outlined below? Design flow velocities; Gutters Conduit Culverts Swales Channels Highest (feet per second) N/A N/A N/A N/A N/A Lowest (feet per second) N/A N/A N/A N/A N/A Streets and Storm Drain Systems Provide the summary information outlined below: N/A Roughness coefficients used: For street gutters: For conduit type(s) N/A N/A N/A Coefficients: SECTION IX STORMWATER DESIGN GUIDELINES Page 24 of 26 APPENDIX. D: TECH. DESIGN SUMMARY As Revised February 2009 Effective February 2007 APPENDIX D - TECHNICAL DESIGN SUMMARY Part 4 — Drainage Concept and Design Parameters Continued (Page 4.16) Design Parameters (continued) Hydraulics (continued) Street and Storm Drain Systems (continued) For the following, are assumptions other than allowable per Guidelines? Inlet coefficients? X No Yes Head and friction losses X No Yes Explain any "yes" answer: In conduit is velocity generally increased in the downstream direction? Are elevation drops provided at inlets, manholes, and junction boxes? Explain any "no" answers: Yes No Yes No Are hydraulic grade lines calculated and shown for design storm? Yes No For 100 -year flow conditions? Yes No Explain any "no" answers: What tailwater conditions were assumed at outfall point(s) of the storm drain system? Identify each location and explain: Open Channels If a HEC analysis is utilized, does it follow Sec VI.F.5.a? Yes No Outside of straight sections, is flow regime within limits of sub - critical If "no" list locations and explain: flow? Yes No 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 SECTION IX STORMWATER DESIGN GUIDELINES Page 25 of 26 APPENDIX. D: TECH. DESIGN SUMMARY Effective February 2007 APPENDIX D - TECHNICAL DESIGN SUMMARY As Revised February 2009 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 Microsoft Office Excell 2007 was used to calculate Rational Method equations Part 5 — Plans and Specifications Requirements for submittal of construction drawings and specifications do not differ due to use of a Technical Design Summary Report. See Section III, Paragraph C3. Part 6 — Conclusions and Attestation Conclusions Add any concluding information here: Attestation Provide attestation to the accuracy and completeness of the foregoing 6 Parts of this Technical Design Summary Drainage Report by signing and sealing below. "This report (plan) for the drainage design of the development named in Part izi. ared by me (or under my supervision) in accordance with provisions of the Br ! Cah Qn ' -d Drainage Design Guidelines f o r the owners of the property. AIL'i sd .. d i enh, ) i equ ed by - y and all state and federal regulatory agencies for ekriopo' -+ d ra m a , impr•vem-nt• have been issued or fall under applicable general pernft ". 0 / SAM J. VERNON (Affix Seal) 0 i AL t 99353 : a/ 1 !cense. o fessional Engineer + ' � ‘-,s,. / ONA� - ��C -` State of Texas PE No. 99 3 bl` i �� SECTION IX Effective February 2007 APPENDIX D - TECHNICAL DESIGN SUMMARY STORMWATER DESIGN GUIDELINES Page 26 of 26 APPENDIX. D: TECH. DESIGN SUMMARY As Revised February 2009