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Home My WebLink AboutDrainage Report DRAINAGE REPORT FOR DUCK HAVEN SUBDIVISION PHASE 7 b. January 2015 Revised March 2015 PREPARED FOR: SMILING MALLARD DEVELOPMENT, LTD. 3608 EAST 29TH STREET BRYAN, TEXAS 77802 979-846-4384 MBESI No. 10620044 McCLURE & BROWNE ENGINEERING/SURVEYING, INC. io 1008 Woodcreek Dr.,Suite 103• College Station,Tx,7845• (979)693-3838 Engineer Reg.No.F-458 Survey Reg.No. 101033-00 Duck Haven Subdivision, Phase 7 Stormwater Management Technical Design Summary Report MBESI No. 10620044 PART 1 -Executive Summary Report 460 Section 1 -Contact Infounation Project Designer: McClure and Browne Engineering and Surveying, Inc. 1008 Woodcreek Drive, Suite 103 0.4 College Station, TX 77845 979-693-3838 Project Developer: Smiling Mallard Development, Ltd. "" 3608 East 29th Street Bryan, Texas 77802 Section 2- General Information and Project Location This development is the 7th phase of a multi phase subdivision. Phase 7 consists of 10 lots. The phase t`` is located in the Duck Haven Village which is along FM 2154 (Wellborn Road). Phase 7 is located at the intersection of Drake Drive and Wigeon Trail Drive. This phase of the subdivision has been analyzed as part of the Phase 3 Drainage Report submitted in September, 2006. The development is entirely located within the Brazos County limits. The project site is in the Peach Creek watershed. According to the Flood Insurance Rate Maps for Brazos County, Texas and incorporated area, Map Number 48041C0375E effective May 16, 2012; no *- portion of this property is located in a 100-year flood hazard area. Culvert pipe calculations are shown with this submittal. 44. The culverts and ditches peak runoffs were found using the Rational Method. A runoff coefficient (c) of 0.50 was used for residential areas since all the lots have an area greater than 1 acre. The culverts and ditches were analyzed using Microsoft Excel spreadsheets which utilizes Manning's Equation for the „r, analysis. 44.44 Section 3 -Reference ow Exhibit A Technical Design Summary "" Exhibit B Drainage Area Map Exhibit C-1 Drainage Area Calculations Exhibit C-2 Culvert Calculations "r Drainage Report 1 Duck Haven Subdivision, Phase 7 EXHIBITS Drainage Report Duck Haven Subdivision, Phase 7 tkile W IWO taw EXHIBIT A Technical Design Summary r 4- IMO aim 41.10 Drainage Report Duck Haven Subdivision, Phase 7 SECTION IX APPENDIX D - TECHNICAL DESIGN SUMMARY The Cities of Bryan and College Station both require storm drainage design to follow these Unified Stormwater Design Guidelines. Paragraph C2 of Section III (Administration) requires submittal of a drainage report in support of the drainage plan (stormwater management plan) proposed in connection with land development projects, both site projects and subdivisions. That report may be submitted as a traditional prose report, complete with applicable maps, graphs, tables and drawings, or it may take the form of a "Technical Design Summary". The format and content for such a summary report shall be in substantial conformance with the description in this Appendix to those Guidelines. In either format the report must answer the questions (affirmative or negative) and provide, at minimum, the information prescribed in the "Technical Design Summary" in this Appendix. The Stormwater Management Technical Design Summary Report shall include several parts as listed below. The information called for in each part must be provided as applicable. In addition to the requirements for the Executive Summary, this Appendix includes several pages detailing the requirements for a Technical Design Summary Report as forms to be completed. These are provided so that they may be copied and completed or scanned and digitized. In addition, electronic versions of the report forms may be obtained from the City. Requirements for the means (medium) of submittal are the same as for a conventional report as detailed in Section III of these Guidelines. Note: Part 1 — Executive Summary must accompany any drainage report required to be provided in connection with any land development project, regardless of the format chosen for said report. Note: Parts 2 through 6 are to be provided via the forms provided in this Appendix. Brief statements should be included in the forms as requested, but additional information should be attached as necessary. Part 1 — Executive Summary Report Part 2— Project Administration Part 3— Project Characteristics Part 4— Drainage Concept and Design Parameters Part 5— Plans and Specifications Part 6— Conclusions and Attestation STORMWATER MANAGEMENT TECHNICAL DESIGN SUMMARY REPORT Part 1 — Executive Summary This is to be a brief prose report that must address each of the seven areas listed below. Ideally it will include one or more paragraphs about each item. 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. 2. Identification of the size and general nature of the proposed project, including any proposed project phases. This paragraph should also include reference to applications that are in process with either City: plat(s), site plans, zoning requests, STORMWATER DESIGN GUIDELINES Page 1 of 26 APPENDIX. D: TECH. DESIGN SUMMARY Effective February 2007 As Revised February 2009 SECTION IX APPENDIX D — TECHNICAL DESIGN SUMMARY ao or clearing/grading permits, as well as reference to any application numbers or codes assigned by the City to such request. wit 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 VMS approximate acreage in each basin, and whether its position in the Watershed dictates use of detention design. The approximate proportion of the property in the city limits and within the ETJ is to be identified, including whether the property straddles city jurisdictional lines. If any portion of the property is in floodplains as described in Flood Insurance Rate Maps published by FEMA that should be le 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. ' .00 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 PO features: storm drains coupled with streets; detention / retention facilities; buried conveyance conduit independent of streets; swales or channels; bridges or culverts; outfalls to principal watercourses or their tributaries; and treatment(s) of existing watercourses. Also, any plans for reclaiming land within floodplain areas must be outlined. 6. Coordination and permitting of stormwater matters must be addressed. This is to include any specialized coordination that has occurred or is planned with other entities (local, state, or federal). This may include agencies such as Brazos County government, the Brazos River Authority, the Texas A&M University System, the Texas Department of Transportation, the Texas Commission for Environmental ma Quality, the US Army Corps of Engineers, the US Environmental Protection Agency, et al. Mention must be made of any permits, agreements, or understandings that pertain to the project. 7. Reference is to be made to the full drainage report (or the Technical Design Summary Report) which the executive summary represents. The principal elements of the main report (and its length), including any maps, drawings or construction documents, should be itemized. An example statement might be: "One -page drainage report dated , one set of construction drawings ( sheets) dated , and a -page specifications document dated comprise the drainage report for this project." two no le low STORMWATER DESIGN GUIDELINES Page 2 of 26 APPENDIX. D:TECH. DESIGN SUMMARY Effective February 2007 As Revised February 2009 SECTION IX APPENDIX D - TECHNICAL DESIGN SUMMARY Part 2 — Protect Administration Start (Page 2.1) Engineering and Design Professionals Information Engineering Firm Name and Address: Jurisdiction McClure & Browne Engineering/Surveying, Inc. City: Bryan 1008 Woodcreek Drive, Suite 103 X College Station College Station, Texas 77845 Date of Submittal: (979)693-3838 lie Lead Engineer's Name and Contact Info.(phone, e-mail, fax): Other: Jeffery L. Robertson, P.E. Supporting Engineering/Consulting Firm(s): Other contacts: Developer/ Owner/Applicant Information Developer/Applicant Name and Address: Phone and e-mail: fr Smiling Mallard Development, Ltd. (979) 846-4384 3608 East 29th Street Bryan, Texas 77802 Property Owner(s) if not Developer/ Applicant(&address): Phone and e-mail: Project Identification Development Name: Duck Haven, Phase 7 Is subject property a site project, a single-phase subdivision, or part of a multi-phase subdivision? Multi-phase Subdivision If multi-phase, subject property is phase 7 of Legal description of subject property(phase) or Project Area: (see Section II, Paragraph B-3a) Duck Haven, Phase 6 I 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. The project is the 7th phase of a multi phase subdivision. At this time the first phases have been built. The most recent phase submitted was Ph. 6. j General Location of Project Area, or subject property (phase): Project site is located near the intersection of Wigeon Trail and Drake Drive in Brazos County, Texas. In City Limits? Extraterritorial Jurisdiction (acreage): Bryan: acres. Bryan: College Station: 12.047 1 College Station: acres. Acreage Outside ETJ: STORMWATER DESIGN GUIDELINES Page 3 of 26 APPENDIX. D:TECH. DESIGN SUMMARY Effective February 2007 As Revised February 2009 p SECTION IX APPENDIX D - TECHNICAL DESIGN SUMMARY Part 2 — Project Administration Continued (page 2.2) Project Identification (continued) witt Roadways abutting or within Project Area or Abutting tracts, platted land, or built subject property: developments: Drake Drive Duck Haven Phase 1 OP IIW Named Regulatory Watercourse(s) &Watershed(s): Tributary Basin(s): Phase 7 is located in the Franks Creek and Boggy The nearest tributary is Peach Creek S. 1111, Creek Watersheds. Tributary 7.2 (See FEMA Map 48041C0375E) . are Plat Information For Project or Subject Property (or Phase) Preliminary Plat File#: Final Plat File#: Date: mm Name: Pending Approval Status and Vol/Pg: Pending Approval If two plats, seco Status: — Data: woo Zoning Information For Project or Subject Property (or Phase) Zoning Type: Existing or Proposed? Case Code: Case Date Status: Zoning Type: Existing or Proposed? Case Code: „m Case Date Status: IR Stormwater Management Planning For Project or Subject Property (or Phase) mo nning Conference(s) & Date(s): Participants: OR 60 Preliminary Report Require• Submittal Date -eview Date •m Review Comments Addressed? Yes No In Wr g? When? Op Compliance With Preliminary Drainage R• : •rt. : efly describe (or attach documentation ,r,,, explaining) any deviation(s)from provisions of P inary Drainage Report, if any. OP 149141, 40 MO /10 STORMWATER DESIGN GUIDELINES Page 4 of 26 APPENDIX. D:TECH. DESIGN SUMMARY Effective February 2007 As Revised February 2009 SECTION IX APPENDIX D - TECHNICAL DESIGN SUMMARY Part 2 — Project Administration Continued (page 2.3) Coordination For Project or Subject Property (or Phase) Note: For any Coordination of stormwater matters indicated below, attach documentation describing and substantiating any agreements, understandings, contracts, or approvals. Coordina i Dept. Contact: Date: Subject:—� With Other Departments of Jurisdiction —monCity (Bryan or College Station - ... Coordination With mmarize need(s) &actions taken (include contacts&dates): ' " Non-jurisdiction City Needed? tea., X Yes No Coordination with Summarize need(s : actions taken (include contacts •ates): Brazos County Needed? Yes No X Coordination with ww Summarize need(s) &actions take• in de contacts &dates): TxDOT Needed? Yes No X w. Summarize ne=• s) &actions taken (include contacts &da , : Coordination with TAMUS Needed? Yes No X 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 Status of Actions (include dates) Approved ? US Army Crops of Engineers No X Yes US Environmental Protection Agency No X Yes Texas Commission on A Stormwater Pollution Prevention Plan must be Environmental Quality implemented prior to the start of construction NO Yes x according to TPDES General Permit No. TXR150000. 0. Brazos River 66 Authority No X Yes rig STORMWATER DESIGN GUIDELINES Page 5 of 26 APPENDIX. D:TECH. DESIGN SUMMARY Effective February 2007 As Revised February 2009 ow uw SECTION IX APPENDIX D - TECHNICAL DESIGN SUMMARY .A Part 3 — Property Characteristics Start (Page 3.1) Nature and Scope of Proposed Work O P Existing: Land proposed for development currently used, including extent of impervious cover? Existing undeveloped land. Existing impervious cover is WO approximately 0 sf. U •evelo•ment of one platted lot, or two or more adjoining slat-: • s. Site Development Building on a -• e platted lot of undeveloped la •. Project Building on two or more pla = _d'•'-' • lots of undeveloped land. me (select all applicable) Building on a single • , • adjoining lots, - - •ro•osed plat will not form •r a new stre may include ROW dedication to e : streets). er(explain): Subdivision X Construction of streets and utilities to serve one or more platted lots. Development Construction of streets and utilities to serve one or more proposed lots on • Project lands represented by pending plats. sof Site projects: building use(s), approximate floor space, impervious cover ratio. Describe Subdivisions: number of lots by general type of use, linear feet of streets and OP Nature and drainage easements or ROW. This phase of the subdivision includes 10 lots. The development Size of consists of approximately 885 LF of streets and 70' ROW. Proposed 110 Project rrW Is any work planned on land that is not platted '--, -..Iain: or on land for which platting is not pending'? > 114 X No Yes r FEMA Floodplains • Is any part of subject property abutting a Named Regulatory Watercourse No X Yes (Section II, Paragraph B1) or a tributary thereof? Is any part of subject property in floodplain OR area of a FEMA-regulated watercourse? No X Yes Rate Map 4804100375E mis Encroachment(s) Encroac urpose(s): Building site(s) Roas _ ng(s) into Floodplain areas planned? Utility crossing(s) ther(ex• No X •r• Yes ••:- areas not shown on Rate Maps, has work been done toward amending the F approved Floc). • • define allowable encroachments in proposed are. . . ain. NS um PP STORMWATER DESIGN GUIDELINES F'age 6 of 26 APPENDIX. D:TECH. DESIGN SUMMARY „ss Effective February 2007 As Revised February 2009 SECTION IX APPENDIX D - TECHNICAL DESIGN SUMMARY Part 3 — Property Characteristics Continued (Page 3.2) Hydrologic Attributes of Subject Property (or Phase) Has an earlier hydrologic analysis been done for larger area including subject property? ft. Reference the study(& date) here, and attach copy if not already in City files. Yes Duck Haven Subdivision; October, 2006 X sim IYr Is the stormwater management plan for the property in substantial conformance with the oft earlier study? Yes X No If not, explain how it differs. No If subject property is not part of multi-phase project, describe stormwater management plan for the property in Part 4. — If property is part of multi-phase project, provide overview of stormwater management plan 4.1 for Project Area here. In Part 4 describe how plan for subject property will comply therewith. OW Stormwater Detention has been provided for this phase with a detention pond developed with a previous phase. bo Do existing topographic features on subject property store or detain runoff? X No Yes Describe them (include approximate size, volume, outfall, model, etc). Any known drainage or flooding problems in areas near subject property? X No Yes Identify: Based on location of study property in a watershed, is Type 1 Detention (flood control) needed? m. (see Table B-1 in Appendix B) Detention is required. Need must be evaluated. Detention not required. What decision has been reached? By whom? Detention study during Phase 3. If the need for How was determination made? Type 1 Detention Detention was required and is provided for the entire must be evaluated: Duck Haven Subdivision. However, Phase 7 does not require any additional detention. am STORMWATER DESIGN GUIDELINES Page 7 of 26 APPENDIX. D:TECH. DESIGN SUMMARY Effective February 2007 As Revised February 2009 SECTION IX APPENDIX D - TECHNICAL DESIGN SUMMARY 410 Part 3 — Property Characteristics Continued (Page 3.3) Hydrologic Attributes of Subject Property(or Phase) (continued) Does subject property straddle a Watershed or Basin divide? X No Yes If yes, describe splits below. In Part 4 describe desi•n conce•t for handlin• this. tow Watershed or Basin II cc IMMO 1116 w Above-Project Areas(Section II, Paragraph B3-a) Does Project Area (project or phase) receive runoff from upland areas? X No Yes Size(s) of area(s) in acres: 1) 2) 3) 4) Flow Characteristics (each instance) (overland sheet, shallow concentrated, recognizable concentrated section(s), small creek (non-regulatory), regulatory Watercourse or tributary); Flow determination: Outline hydrologic methods and assumptions: Rational Method used for flow determination. OW Does storm runoff drain from public easements or ROW onto or across subject property? on X No Yes If yes, describe facilities in easement or ROW: Are changes in runoff characteristics subject to change in future? Explain No. Existing facilities have been built and plat has been filed. ah um Conveyance Pathways (Section II, Paragraph C2) Must runoff from study property drain across lower properties before reaching a Regulatory Watercourse or tributary? X No Yes Describe length and characteristics of each conveyance pathway(s). Include ownership of property(ies). Proposed drainage from this phase will enter Phase 8 ROW which is currently OS being reviewed for approval. Phase 8 will connect to the same tributary Phase 3 storm water enters. ON NO fie OW STORMWATER DESIGN GUIDELINES Page 8 of 26 APPENDIX. D:TECH. DESIGN SUMMARY Effective February 2007 As Revised February 2009 SECTION IX APPENDIX D - TECHNICAL DESIGN SUMMARY Part 3 — Property Characteristics Continued (Page 3.4) Hydrologic Attributes of Subject Property (or Phase) (continued) Conveyance Pathways (continued) Do drainage If yes, for what part of length? % Created by? X plat, or easements instrument. If instrument(s), describe their provisions. exist for any part of pathway(s)? No Yes Where runoff must cross lower properties, describe characteristics of abutting lower property(ies). (Existing watercourses? Easement or Consent aquired?) Pathway Areas Describe any built or improved drainage facilities existing near the property (culverts, bridges, lined channels, buried conduit, swales, detention ponds, etc). Nearby Drainage Do any of these have hydrologic or hydraulic influence on proposed stormwater Facilities design? X No Yes If yes, explain: STORMWATER DESIGN GUIDELINES Page 9 of 26 APPENDIX. D:TECH. DESIGN SUMMARY Effective February 2007 As Revised February 2009 SECTION IX APPENDIX D — TECHNICAL DESIGN SUMMARY .� Part 4— Drainage Concept and Design Parameters Start (Page 4.1) Stormwater Management Concept Discharge(s) From Upland Area(s) .rr 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, w flow section, or discharge point. NO Discharge(s) To Lower Property(ies) (Section II, Paragraph El) Does project include drainage features (existing or future) proposed to become public via ON platting? x No Yes Separate Instrument? X No Yes ow Per Guidelines reference above, how will Establishing Easements (Scenario 1) runoff be discharged to neighboring property(ies)? Pre-development Release (Scenario 2) 1111 Combination of the two Scenarios wo Scenario 1: If easements are proposed, describe where needed, and provide status of actions on each. (Attached Exhibit# ) OR Scenario 2: Provide general description of how release(s)will be managed to pre-development rift conditions (detention, sheet flow, partially concentrated, etc.). (Attached Exhibit# ) Detention Pond built with previous phases. ON 4116 1!R ww 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. wr 111/ ON If Scenario 2, or Combination are to be used, has proposed design been coordinated with owner(s) of receiving property(ies)? No Yes Explain and provide U documentation. l STORMWATER DESIGN GUIDELINES Page 10 of 26 APPENDIX. D:TECH. DESIGN SUMMARY Effective February 2007 As Revised February 2009 40 SECTION IX APPENDIX D - TECHNICAL DESIGN SUMMARY Part 4 — Drainage Concept and Design Parameters Continued (Page 4.2) Stormwater Management Concept(continued) Within Project Area Of Multi-Phase Project •-- ' gaining Basins or Watersheds and acres shifting: Will project result in shifting runoff between Basins or between What design and mitigation is us-: . pensate for increased runoff Watersheds? from gaining basin or watersh-• . X No Yes How will runoff from Project 1. With facility(ies) involving other development projects. Area be mitigated to pre- 2. Establishing features to serve overall Project Area. development conditions? Select any or all of 1, 2, 3. X On phase (or site) project basis within Project Area. and/or 3, and explain below. . eared facilit (type& location of facility; design drainage area served; relationship to siz- Project • : (Attached Exhibit# 2. For Overall Project Area (type & loc- of facili i- • Attached Exhibit# 3. By phase (or site) project: Describe planned mitigation measures for phases (or sites) in subsequent questions of this Part. • - aquatic echosystems proposed? No Yes In which phase(s) or projec ? cs- -a (1) >- Are other Best Manage •-nt Practices for reducing stormwate •.Ilutants proposed? as No Yes Su -rize type of BMP and : ent of use: C O1 O a Z 7-13 XIIf design of any runoff-handline -cilities deviate from p : isions of B-CS Technical Specifications, check ty.- acility(ies) and explain in later qu- ions. Detention - ents Conduit elements Cha •-I features Sw- Ditches Inlets Valley gutters • alls Culvert features Bridges Other STORMWATER DESIGN GUIDELINES Page 11 of 26 APPENDIX. D: TECH. DESIGN SUMMARY Effective February 2007 As Revised February 2009 SECTION IX _ APPENDIX D - TECHNICAL DESIGN SUMMARY Part 4— Drainage Concept and Design Parameters Continued (Page 4.3) Stormwater Management Concept(continued) 11. Within Proiect Area Of Multi-Phase Project(continued) Will Project Area include bridge(s) or culvert(s)? No X Yes Identify type and general size and In which phase(s). Proposed double 18" RCP culvert at Wigeon Trail and Drake Drive so 10 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): se Existing Detention pond in HOA Common Area serves this phase. 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 X No, then summarize the difference(s): OP 140, 4101 Identify whether each of the types of drainage features listed below are included, extent of use, and general characteristics. Typical shape? Surfaces? �• V-Shape Grass wW 3 Steepest side slopes: Usual front slopes: Usual back slopes: 4:1 4:1 4:1 N tok X Flow line slopes: least ° 99° Typical distance from travelway: 11' o typical Varies greatest 6.0%° (Attached Exhibit#_ ) z 2 Are longitudinal culvert ends in compliance with B-CS Standard Specifications? Yes No, then explain: we rse� ctions or otherwise, do valley gutters cross arterial or collector stre- . . c••• 'f?o�,, Yes If yes explain: w� U m Are valley gutters proposed to cross . -- away from an intersection? ( o No Yes Explain. •. .er of loca is rnz 2 m x Q .�r STORMWATER DESIGN GUIDELINES Page 12 of 26 APPENDIX. D:TECH. DESIGN SUMMARY ,W,; Effective February 2007 As Revised February 2009 SECTION IX APPENDIX D - TECHNICAL DESIGN SUMMARY Part 4— Drainage Concept and Design Parameters Continued (Page 4.4) Stormwater Management Concept(continued) r ill Within Or Serving Subject Property(Phase, or Site) (continued) . tter line slopes: Least Usual Greatest 1 Are i ets recessed on arterial and collector streets? Yes No "no", identify here and why. I Will inlets captu : 10-year design stormflow to prevent flooding of' tersections (arterial with arterial or colle. or)? Yes No If no, expl_' where and why not. cs. � Will inlet size and placemen •revent exceeding allowa- e water spread for 10-year m design storm throughout site (o shase)? Y-: No If no, explain. rn I cri 5 Sad curves: Are inlets placed at low poin . Yes No Are inlets and • •� conduit sized to prevent 100-year storm • om ponding at greater than 24 inches? •,•• s o Yes No Explain "no" answe Ir N m u, L 2 Will 100-yr stormflow b- ontained in combination of ROW a • buried conduit on Q whole length of all str-ets? Yes No If no, des 'be where and why. r Do desig for curb, gutter, and inlets comply with B-CS Technical Specific-:ons? es No If not, describe difference(s) and attach justification. so j • - any 12 inch laterals used? No Yes Identify length(s) and wher used. E a) Crl CI) Pipe runs between tern Typical Longest 7 e access points (feet): aa)) Are junction boxes used at each .- d? Yes No If not, explain where N and why. c uo• as Z E x .� II) Are downstream soff' = at or below upstream soffits? Leas _• ount that hydraulic too NYes N. If not, explain where and why: grade line selow gutter line (system-wide): r STORMWATER DESIGN GUIDELINES Page 13 of 26 APPENDIX. D:TECH. DESIGN SUMMARY ior Effective February 2007 As Revised February 2009 SECTION IX APPENDIX D - TECHNICAL DESIGN SUMMARY Part 4— Drainage Concept and Design Parameters Continued (Page 4.5) Stormwater Management Concept(continued) Within Or Serving Subject Property(Phase, or Site) (continued) Describe watercourse(s), or system(s) receiving system discharge(s) below (LI (include design discharge velocity, and angle between converging flow line . U 1) -tercourse (or system), velocity, and angle? m rr elk o E 2) Watercourse • system), velocity, and angle? sii c o Li 110 E °' .r E3)Watercourse (or system), veloci _-. angle? N d 4242 c -a O .ET2 13 Mit a E —6 For each outfall abov-, what measures are taken to . event erosion or scour of Nreceiving and all - ilities at juncture? OP CO 0 1) tea i� 2)a) CD 3) not Are swale(s) situated along property lines between properties? No X Yes Number of instances: For each instance answer the following questions. Surface treatments (including low-flow flumes if any): 0 to a) 2 N Flow line slopes (minimum and maximum): ■1 c o z Outfall characteristics for each (velocity, convergent angle, & end treatment). U) X c6 on � wr Q Will 100-year design storm runoff be contained within easement(s) or platted drainage ROW in all instances? Yes No If"no" explain: MO we MO STORMWATER DESIGN GUIDELINES Page 14 of 26 APPENDIX. D:TECH. DESIGN SUMMARY Effective February 2007 As Revised February 2009 ito r SECTION IX 6 APPENDIX D - TECHNICAL DESIGN SUMMARY I 6 Part 4— Drainage Concept and Design Parameters Continued (Page 4.6) Stormwater Management Concept(continued) IWithin Or Serving Subject Property (Phase, or Site) (continued) Are roadside ditches used? No X Yes If so, provide the following: a) Is 25-year flow contained with 6 inches of freeboard throughout? X Yes No Are top of banks separated from road shoulders 2 feet or more? X Yes No oAre all ditch sections trapezoidal and at least 1.5 feet deep? Yes X No N For any"no" answers provide location(s) and explain: I mct All Ditches are V-shaped and at least 2 ' deep 0 I conduit is beneath a swale, provide the following information (each instance). Ins <nce 1 Describe general location, approximate length: >- Is 100-ye. design flow contained in conduit/swale combination? Ye No UIf "no" expla' : 1 0 m Space for 100-ye:r storm flow? ROW Z Easement W'•th .c Swale Surface ty•-, minimum Conduit Type and size, minim and maximum X To and maximum slopes: slopes, design storm: I c O w -a Tu m Inlets Describe how condui 's loaded (from streets/stor ' drains, inlets by type): c c I c m o L U O O O c Access Describe how maintenance - cess is p •vided (to swale, into conduit): I " m o E D o m ,p_ c .E a, Instance 2 Describe general location, =ppro ' ate length: I 73 ) E a) m c a'• -a Is 100-year design flow containe• in conduit/swale c•• bination? Yes No g o If "no" explain: I '-`2' a 1 13 m o s Space for 100-year storm ow? ROW Easement Width • a Swale Surface type, ' imum Conduit Type and size, mi um and maximum 5 i6 and maximum slope • slopes, design storm: m o N Inlets Describe •ow conduit is loaded (from streets/storm drains, inl- by type): m I � c 3 O QAccess riescribe how maintenance access is provided (to swale, into condu : r ISTORMWATER DESIGN GUIDELINES Page 15 of 26 APPENDIX. D:TECH. DESIGN SUMMARY Effective February 2007 As Revised February 2009 SECTION IX APPENDIX D - TECHNICAL DESIGN SUMMARY Part 4— Drainage Concept and Design Parameters Continued (Page 4.7) Stormwater Management Concept(continued) Within Or Serving Subject Property(Phase, or Site) (continued) "" ''yes" provide the following information for each instance: "` Inst. ce 1 Describe general location, approximate length, surfacing: or Q ow 6 Is 100-year design •w contained in swale? Yes No Is swale wholly c >_ within drainage ROW. _Yes No Explain "no" - swers: med oAccess Describe how mainte -nce access is provide. L 0 wooz C Mm 0 x Instance 2 Describe general location, ap7 ximate length, surfacing: a) z m o E _c a> .3 Is 100-year design flow co :med in swale? Yes No Is swale wholly a °' within drainage ROW? Yes No Explain "no -nswers: �w `o N Access Descr how maintenance access is provided: U I a ow Ins :nce 3,4, etc. If swales are used in more than two instances, attach sheet • oviding all above information for each instance. -w" channels: Will any area(s) of concentrated flow be channelized (deepened wide =• or straightened) or otherwise altered? No Yes If only s tly shaped, s- "Swales" in this Part. If creating side banks, provide informati elow. .c Will design repli : e natural channel? Yes No If"no" •r each instance o Q describe section shad- & area, flow line slope (min. & max.), s --ces, and 100-year o w design flow, and amount • reeboard: U Instance 1: MO U) • >_ a) E U m Instance 2: so n E z m NI x Instance 3: ows U err STORMWATER DESIGN GUIDELINES Page 16 of 26 APPENDIX. D:TECH. DESIGN SUMMARY Effective February 2007 As Revised February 2009 All SECTION IX APPENDIX D - TECHNICAL DESIGN SUMMARY Part 4— Drainage Concept and Design Parameters Continued (Page 4.8) Stormwater Management Concept (continued) Within Or Serving Subject Property(Phase, or Site) (continued) \Existing channels (small creeks): Are these used? No Yes I "yes" provide the information below. Wi small creeks and their floodplains remain undisturbed? Yes No How man disturbance instances? Identify each planned location: For each loc-tion, describe length and general type of proposed improv-ment (including floc).slain changes): I For each location, des• ibe section shape & area, flow line sl•se (min. & max.), surfaces, and 100-year •-sign flow. ii =6'3m c c Watercourses (and tributaries): • .ide from fri se changes, are Regulatory o Watercourses proposed to be altered: o Yes Explain below. c Submit full report describing proposed c _n•-s to Regulatory Watercourses. Address E existing and proposed section size and sh•4•e, surfaces, alignment, flow line changes, length affected, and capacity, and provide f documentation of analysis procedures o D. and data. Is full report submitted? Y_s No If"no" explain: E c _`c All Proposed Channel Work: or all proposed chan el work, provide information U requested in next three boxe . I If design is to replicate nat al channel, identify location a • length here, and describe design in Special Design .ection of this Part of Report. I Will 100-year flo be contained with one foot of freeboard? Y- No If not, identify loc. ion and explain: I Are RO' /easements sized to contain channel and required maintenance spate? 'es No If not, identify location(s) and explain: — 1 1 is STORMWATER DESIGN GUIDELINES Page 17 of 26 APPENDIX. D:TECH. DESIGN SUMMARY Effective February 2007 As Revised February 2009 SECTION IX APPENDIX D — TECHNICAL DESIGN SUMMARY oot Part 4— Drainage Concept and Design Parameters Continued (Page 4.9) Stormwater Management Concept(continued) Within Or Serving Subject Property(Phase, or Site) (continued) ■r ow many facilities for subject property project? For each provide info. belo . F. each dry-type facilitiy: Facility 1 Facility 2 111111 Acre served &design volume+ 10% 100-yr ,olume: free flow& plugged Design di- harge (10 yr&25 yr) Spillway cre- at 100-yr WSE? yes no y-s no Berms 6 inche above plugged WSE? yes no yes no ON Explain any"no" - swers: VW aNO >- rrr For each facility what is 25- design Q, and design of ou -t structure? Facility 1: Facility 2: mut x Do outlets and spillways discharge i'to a public f-•ility in easement or ROW? Facility 1: Yes No Facilit. 2: Yes No mIf"no" explain: - o. 0 a. For each, what is velocity of 25-yr desk; disch:rge at outlet? & at spillway? m Facility 1: & Faci' 2: & Are energy dissipation measures .ed? No Yes Describe type and location: 0 m a) 0 Iwo For each, is spillway su -ce treatment other than concrete? es or no, and describe: Facility 1: Facility 2: Mat For each, what easures are taken to prevent erosion or scour at rec-'ving facility? 4111 Facility 1: Facility 2: If berm are used give heights, slopes and surface treatments of sides. fli Facili 1: acility 2: Q1 STORMWATER DESIGN GUIDELINES Page 18 of 26 APPENDIX. D:TECH. DESIGN SUMMARY 111110 Effective February 2007 As Revised February 2009 All! r SECTION IX APPENDIX D - TECHNICAL DESIGN SUMMARY Part 4— Drainage Concept and Design Parameters Continued (Page 4.10) Stormwater Management Concept(continued) rifi, Within Or Serving Subject Property(Phase, or Site) (continued) •. tructures comply with B-CS Specifications? Yes or no, and explain if"no": Facility 1; 1 N .) 7 2n' Facility 2: c c o c C UN 0 For additional faciliti- • ovide all same information on a sepa . - sheet. I Are parkin• - -as to be used for detention? No Yes - ma..- m depth due to required design storm? Roadside Ditches: Will culverts serve access driveways at roadside ditches? No X Yes If"yes", provide information in next two boxes. Will 25-yr. flow pass without flowing over driveway in all cases? X Yes No Without causing flowing or standing water on public roadway? X Yes No I Designs &materials comply with B-CS Technical Specifications? X Yes No Explain any"no" answers: I u) 0) I o Are culverts parallel to public roadway alignment? X Yes No Explain: U 2 m } I n. X( Creeks at Private Drives: Do private driveways, drives, or streets cross drainage m ways that serve Above-Project areas or are in public easements/ROW? m0 z X No Yes If"yes" provide information below. 1u) rn • How many instances? Describe location and provide information below. CLi All lots will need ditch crossing culverts to • Location 1: access Wigeon Trail. Each proposed lot will need I 0 a minimum of an 18" culvert. 2 Q Location 2: Location 3: IFor each location enter value for: 1 2 3 Design year passing without toping travelway? IWater 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. u ilii STORMWATER DESIGN GUIDELINES Page 19 of 26 APPENDIX. D:TECH. DESIGN SUMMARY IEffective February 2007 As Revised February 2009 pm SECTION IX APPENDIX D - TECHNICAL DESIGN SUMMARY OW Part 4— Drainage Concept and Design Parameters Continued (Page 4.11) Stormwater Management Concept(continued) Of Within Or Serving Subject Property(Phase, or Site) (continued) Named Regulatory Watercourses (&Tributaries): Are culverts proposed on these facilities? X No Yes, then provide full report documenting assumptions, PP criteria, analysis, computer programs, and study findings that support proposed design(s). Is report provided? Yes No If"no", explain: _,. OW m Arterial or Major Collector Streets: Will culverts serve these types of roadways? 0. a) c X No Yes How many instances? For each identify the a, location and provide the information below. , } n Instance 1: a1,' Instance 2: x c pa o Instance 3: c O o .7a Yes or No for the 100-year design flow: 1 2 3 z o Headwater WSE 1 foot below lowest curb top? c tip; .(7) a.Spread of headwater within ROW or easement? IMP al (ten' Is velocity limited per conditions (Table C-11)? owt c 73 •N c Explain any"no" answer(s): o° pc > f0 0. (n o O a N iViCa o :n Minor Collector or Local Streets: Will culverts serve these types of streets? a _ No X Yes How many instances? 1 for each identify the ow location and provide the information below: a. a> n. Instance 1: Wigeon Trail and Drake Drive m >• ao c Instance 2: n • o Instance 3: ,,.- CT) • a� c For each instance enter value, or"yes"I"no" for4 1 2 3 , U c6 a, c Design yr. headwater WSE 1 ft. below curb top? Yes — 2 100-yr. max. depth at street crown 2 feet or less? Yes O Product of velocity (fps) &depth at crown ft ? 0 OP Is velocity limited per conditions (Table C-11)? Yes ,,,, Limit of down stream analysis (feet)? 50 ' OS Explain any"no" answers: trait OP Vole int STORMWATER DESIGN GUIDELINES Page 20 of 26 APPENDIX. D:TECH. DESIGN SUMMARY ato Effective February 2007 As Revised February 2009 a* SECTION IX APPENDIX D — TECHNICAL DESIGN SUMMARY ' Part 4— Drainage Concept and Design Parameters Continued (Page 4.12) Stormwater Management Concept(continued) ' Within Or Serving Subject Property(Phase, or Site) (continued) All Proposed Culverts: For all proposed culvert facilities (except driveway/roadside ditch intersects) provide information requested in next eight boxes. ' Do culverts and travelways intersect at 90 degrees? X Yes No If not, identify location(s) and intersect angle(s), and justify the design(s): 1 Does drainage way alignment change within or near limits of culvert and surfaced approaches thereto? X No Yes If"yes" identify location(s), describe change(s), and justification: Are flumes or conduit to discharge into culvert barrel(s)? X No Yes If yes, identify location(s) and provide justification: Are flumes or conduit to discharge into or near surfaced approaches to culvert ends? No X Yes If"yes" identify location(s), describe outfall design treatment(s): (i) Areas are protected with Rock Rip-Rap Channel Lining 0 a) Is scour/erosion protection provided to ensure long term stability of culvert structural components, and surfacing at culvert ends? X Yes No If"no" Identify locations and provide justification(s): Will 100-yr flow and spread of backwater be fully contained in street ROW, and/or drainage easements/ROW? X Yes No if not, why not? r Do appreciable hydraulic effects of any culvert extend downstream or upstream to neighboring land(s) not encompassed in subject property? X No Yes If "yes" describe location(s) and mitigation measures: I IP Are all culvert designs and materials in compliance with B-CS Tech. Specifications? X Yes No If not, explain in Special Design Section of this Part. ow STORMWATER DESIGN GUIDELINES Page 21 of 26 APPENDIX. D:TECH. DESIGN SUMMARY Effective February 2007 As Revised February 2009 SECTION IX APPENDIX D - TECHNICAL DESIGN SUMMARY Part 4— Drainage Concept and Design Parameters Continued (Page 4.13) Stormwater Management Concept(continued) PO Within Or Serving Subject Property (Phase, or Site) (continued) - bridge included in plans for subject property project? No Yes If"ye " •rovide the following information. Name(s) a • functional classification of the roadway(s)? What drainage way(s) is to be c , sed? a 73,m witik A full report supporting al =spects of the proposed bridge(s tructural, geotechnical, hydrologic, and hydr_• is factors) must accompany this summa ' -port. Is the report provided? es No If"no" explain: MP Is a Stormwater Provide a general description of planned techniques: Pollution Prevention Silt fence and inlet filtration will serve as the OR Plan (SW3P) main protection against stormwater pollution. The C� established for ' Contractor shall use any other means necessary project construction? throughout construction. MP No X Yes up Special Designs—Non-Traditional Methods ni Are any non-traditional methods (aquatic echosystems, wetland-type detention, natural stream replication, BMPs for water quality, etc.) proposed for any aspect of subject property project? X No Yes If"yes" list general type and location below. full report about the proposed special design(s) including rationale for use and expected be - Report must substantiate that stormwater management ••.- ves will not be compromised, and - -intenance cost will not exceed thos- - -•itional design solution(s). Is report provided? Yes • no" explain: r 110 STORMWATER DESIGN GUIDELINES Page 22 of 26 APPENDIX. D:TECH. DESIGN SUMMARY Effective February 2007 As Revised February 2009 SECTION IX APPENDIX D - TECHNICAL DESIGN SUMMARY Part 4— Drainage Concept and Design Parameters Continued (Page 4.14) Stormwater Management Concept(continued) Within Or Serving Subject Property(Phase, or Site) (continued) s ecial Designs—Deviation From B-CS Technical Specifications If an design(s) or material(s) of traditional runoff-handling facilities deviate from provisions of B-CS :chnical Specifications, check type facility(ies) and explain by specific detail eleme . De = tion elements Drain system elements Channel features Culve -atures Swales Ditches Inlets P tfalls Valley gu = s Bridges (explain in bridge report) In table below briefly i.-ntify specific element,justification for deviation(s). Specific Detail Eleme Justification for Deviation (attach add' '•nal sheets if needed) 1 1) 1 2) 3) 4) OM ISM 5) Have elements been co• :inated with the City Engineer or her/his desi, ee? For each item above provide"yes" •• no", action date, and staff name: 1) 2) 3) 4) II Design Parameters Hydrology 1 1 Is a map(s) showing all Design Drainage Areas provided? X Yes No Briefly summarize the range of applications made of the Rational Formula: For the Rational Formula we assumed residential areas had a I i runoff coefficient of 0.5 for large residential or estate lots. 1 What is the size and location of largest Design Drainage Area to which the Rational Formula has been applied? 4.01 acres Location (or identifier): Culvert #1 1 ill STORMWATER DESIGN GUIDELINES Page 23 of 26 APPENDIX. D:TECH. DESIGN SUMMARY Effective February 2007 As Revised February 2009 to. Il SECTION IX APPENDIX D - TECHNICAL DESIGN SUMMARY OP Part 4— Drainage Concept and Design Parameters Continued (Page 4.15) Design Parameters(continued) OP Hydrology (continued) In making determinations for time of concentration, was segment analysis used? ss" x No Yes In approximately what percent of Design Drainage Areas? OP As to intensity-duration-frequency and rain depth criteria for determining runoff flows, were any criteria other than those provided in these Guidelines used? x No Yes If"yes" identify type of data, source(s), and where applied: Vat OP 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 sss Stor s stem for arterial and collector streets OP Storm drain system for . : -ets aws Open channels Swale/buried conduit co on in lieu of channel Swa - 0104, Roadside ditches and culverts serving them 2,5,10,25,50, 10 0 25 a0 De e '-a facilities: spillway crest and its outfall Detention facilities: .. - and conveyance structure(s) Detention facilities: volume when o .-pluged es Culverts serving private drives or str- Culverts serving pus '. .-.ways Bri.•--. provide in bridge report. was Hydraulics What is the range of design flow velocities as outlined below? Design flow velocities; 25 year Gutters Conduit Culverts Swales Channels MID Highest(feet per second) 9.69 Lowest(feet per second) 8.66 00 Streets and Storm Drain Systems Provide the summary information outlined below: Roughness coefficients used: For street gutters: NA +� For conduit type(s) RCP 0.013 Coefficients: moo 0 STORMWATER DESIGN GUIDELINES Page 24 of 26 APPENDIX. D:TECH. DESIGN SUMMARY Effective February 2007 As Revised February 2009 IOW MI SECTION IX Wiz APPENDIX D - TECHNICAL DESIGN SUMMARY Part 4— Drainage Concept and Design Parameters Continued (Page 4.16) Design Parameters(continued) ' Hydraulics (continued) eet and Storm Drain Systems (continued) For th- ollowing, are assumptions other than allowable per Guidelines? Inlet coeffi '-nts? No Yes Head and friction losses No Yes Explain any"y- " answer: In conduit is velocity general creased in the downstream dire► on? Yes No Are elevation drops provided at in : s, manholes, and juncti. boxes? Yes No Explain any"no" answers: Are hydraulic grade lines calculated and own for •- -ign storm? Yes No For 100-year flow conditions? es No •lain any"no" answers: What tailwater conditi• s were assumed at outfall point(s) of the storm • -in system? Identify each location and - plain: 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 flow? X Yes No If"no" list locations and explain: Culverts If plan sheets do not provide the following for each culvert, describe it here. For each design discharge, will operation be outlet(barrel) control or inlet control? All culverts will be inlet controlled. Entrance, friction and exit losses: A 0.5 entrance and exit loss coefficients are used for sloped end treatments and square edged headwalls with wingwalls. Bridges Provide all in bridge report STORMWATER DESIGN GUIDELINES Page 25 of 26 APPENDIX. D:TECH. DESIGN SUMMARY Effective February 2007 As Revised February 2009 r 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 Microsoft Excel Spreadsheet I 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 oft Add any concluding information here: The Duck Haven Subdivision, Phase 7 will have no adverse impact to downstream properties and conforms to the overall subdivision report. NIP itak Attestation s Provide attestation to the accuracy and completeness of the foregoing 6 Parts of this Technical Nike Design Summary Drainage Report by signing and sealing below. "This report(plan) for the drainage design of the development named in Part B was prepared OP by me (or under my supervision) in accordance with provisions of the Bryan/College Station Unified Drainage Design Guidelines for the owners of the property. All licenses and permits m. required by any and all state and federal regulatory agencies for the proposed drainage improvements have been issued or fall under applicable general permits."t. (Affix Seal) :.r„ F•.; N1) Lic.. s:. Professional Engineer I•. rt.R1 L. Rcr'ERTSO State of Texas PE No. Ili (15 ."?v•., o`t 7 4 5 I .4.r STORMWATER DESIGN GUIDELINES Page 26 of 26 APPENDIX. D:TECH. DESIGN SUMMARY 110.4 Effective February 2007 As Revised February 2009 OP EXHIBIT B Drainage Area Map SOW Awk Moo Drainage Report Duck Haven Subdivision, Phase 7 sew ems Yaw kVA 10. EXHIBIT C Runoff and Culvert Calculations Elmo 1116 Drainage Report Duck Haven Subdivision, Phase 7 ill OM O H N o .-.r� - m Mm iii. 9 N co N O CO r- .2 F►H► ani T •-• • o c W OP* y l0 O O 6O 0WO • d CQ W 6? I I O ; I I . OM Tai I IIa> O N Q d a> a> x I 0 I 0 C C c 0 YID 0 U o I I H r4- ocoOO I ° ado o � a'> 6cflr` oo R m § `-'CJ 0 I w o 0 0 0 0 I I oN7 o— • Q Np O \\II I cjb I „I o .a a o al N O O C J tUa;1E'0 nmvcow O V f0 o N M j O o 0 0 0 N N N CO M CO N N co O =o W 7 C In V. O S. VO J_1H W Z O c0 o c7 ( W II. U O N co co co co N H . / Z W O J H D N Y 0 J O Q co o M CO CO co 0 a. W J -o ✓ Q co > .1- 0 a� co. 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