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Home My WebLink AboutTechnical Design SummarySECTION IX STORMWATER DESIGN GUIDELINES Effective February 2007 APPENDIX D — TECHNICAL DESIGN SUMMARY Start (Page 2.1) Part 2 - Project Administration Engineering and Design Professionals Information Jurisdiction City: Bryan Engineering Firm Name and Address: tZrA� CoKS�11s'(1�sGC ✓ College Station ?,o. j °1253 CA u- pastor c 176`( Supporting Engineering / Consulting Firm(s): Developer / Applicant Name and Address: G . 5 . ?k 17'0M Property Owner(s) if not Developer / Applicant (& address): In City Limits? Bryan: College Station: acres. acres. Date of Submittal: S /I )� Lead Engineer's Name and Contact Info.(phone, e-mail, fax): Other: A. tvl� .7cm-f- (i Ca°►C�- o32°l� Other contacts: Developer / Owner / Applicant Information Phone and e-mail: Phone and e-mail: Project Identification Development Name: Git(_'waG, YV\t .A b4. — Pi Is subject property a site project, a single -phase subdivision, or part of a multi -phase subdivision? If multi phase su ; elf is, phase of Legal description of subject property (phase) or Project Area: (see Section II, Paragraph B -3a) If subject property (phase) is second or later phase of a project, describe general status of all earlier phases. For most recent earlier phase Include submittal and review dates. General Location of Project Area, or subject property (phase): 1 / Extraterritorial Jurisdiction (acreage): Bryan: College Station: Acreage Outside ETJ: Page 3 of 26 APPENDIX. D: TECH. DESIGN SUMMARY As Revised February 2008 Part 2 — Project Administration Continued (page 2.2) Project Identification (continued) Roadways abutting or within Project Area or subject property: p 6 -ver- e T' 4t tl2.1E Tit. Abutting tracts, platted land, or built developments: GdgEsizA jOFLC. 0,4r ..,S Named Regulatory Watercourse(s) & Watershed(s): Fer rF 0-42e ) Tributary Basin(s): Plat Information For Project or Subject Property (or Phase) Preliminary Plat File #: Final Plat Status and File #: Date: Name: VoI/Pg: If two plats, second name: Status: File #: Date: Zoning Information For Project or Subject Property (or Phase) r Proposed? Case Code: Zoning Type: {�IS xisting Case Date Status: Zoning Type: Existing Case Date Status: or Proposed? Case Code: Stormwater Management Planning For Project or Subject Property (or Phase) Planning Conference(s) & Date(s): Participants: Preliminary Report Required? Submittal Date Review Date Review Comments Addressed? Yes No In Writing? When? Compliance With Preliminary Drainage Report. Briefly describe (or attach documentation explaining) any deviation(s) from provisions of Preliminary Drainage Report, if any. SECTION IX Effective February 2007 APPENDIX D — TECHNICAL DESIGN SUMMARY STORMWATER DESIGN GUIDELINES Page 4 of 26 APPENDIX. D: TECH. DESIGN SUMMARY As Revised February 2008 Part 2 — Proiect Administration Continued (page 2.3) Coordination For Project or Subject Property (or Phase) of stormwater matters indicated below, attach documentation any agreements, understandings, contracts, or approvals. Note: For any Coordination describing and substantiating Coordination With Other Departments of Jurisdiction City (Bryan or College Station) Dept. Contact: Date: Subject: Coordination With Non jurisdiction City Needed? Yes No Summarize need(s) & actions taken (include contacts & dates): Coordination with Brazos County Needed? ✓ Yes No Summarize need(s) & actions taken (include contacts & dates): Coordination with TxDOT Needed? Yes No `/ Summarize need(s) & actions taken (include contacts & dates): Coordination with TAMUS Needed'? Yes No 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 US Environmental Protection Agency No Yes �(G'F--C2 �,,1P 3 .: :,iv '� --to G� Texas Commission on Environmental Qual No Yes Brazos River Authority No v Yes SECTION IX APPENDIX D - TECHNICAL DESIGN SUMMARY STORMWATER DESIGN GUIDELINES Page 5 of 26 APPENDIX. D: TECH. D February N SUMMARY Effective February 2007 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 platted lot, or two or more adjoining undeveloped proposed platted Tots. Building on a single lot of undeveloped land. land. plat will not form Building on two or more include platted adjoining lots of Building on a single lot, or adjoining lots, where ROW dedication to a new street (but may Other (explain): existing streets). Subdivision Development Project Construction of streets and utilities to serve one and utilities to serve one pending plats. or or more platted lots. Construction of streets more proposed Tots on lands represented by Describe Nature and Size of Proposed Site projects: building use(s), approximate floor space, impervious cover ratio. by general type of use, linear feet of streets and Subdivisions: number of lots drainage easements or ROW. Project Is any work planned or on land for which o on land that is not platted If yes, explain: platting is not pending? Yes FEMA Floodplains Is any part of subject property abutting a Named Regulatory Watercourse (Section II, Paragraph B1) or a tributary thereof? No ,7 Yes Is any part of subject property in floodplain area of a FEMA - regulated watercourse? No Rate Map M p Encroachment(s) into Floodplain areas planned? No Encroachment purpose(s): Utility crossing(s) Building site(s) Road 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. 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 2008 SECTION IX APPENDIX D - TECHNICAL DESIGN SUMMARY Part 3 — Property Characteristics Hydrologic Attributes of Subject Property (or Phase) Has an earlier hydrologic analysis been done for larger area including subject property? Yes. No Continued (Page 3.2) Reference the study (& date) here, and attach copy if not already in City files. Is the stormwater manage}' ent plan for the property in substantial conformance with the earlier study? Yes r/ No If not, explain how it differs. If subject property is not part of multi -phase project, describe stormwater management plan for the property in Part 4. If property is part of multi -phase project, provide overview of stormwater management plan for Project Area here. In Part 4 describe how plan for subject property will comply therewith. No Do existing topographic features on subject property store or detain runoff? Describe them (include approximate size, volume, outfall, model, etc). Yes If the need for Type 1 Detention must be evaluated: /No Yes Any known drainage or flooding problems in areas near subject property? Identify: Based on location of study property in a watershed, is Type 1 Detention (flood control) needed? (see Table B -1 in Appendix B) Detention is required. Need must be evaluated. Detention not required. What decision has been reached? By whom? How was determination made? STORMWATER DESIGN GUIDELINES Page 7 of 26 APPENDIX. D: TECH. DESIGN SUMMARY Effective February 2007 As Revised February 2008 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 ✓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) -'16 2) 3) No / Yes 4) Flow Characteristics (each instance) (overland sheet, shallow concentrated, recognizable Watercourse or tributary); concentrated section(s), small creek (non - regulatory), regulatory Flow determination: Outline hydrologic methods and assumptions: C...•• Does storm runoff drain from public easements or ROW 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 q �0>- -- FZY[c-bvt bGJ - (S Conveyance Pathways (Section II, Paragraph C2) Must runoff from study property drain across lowerproperties before reaching a Regulatory Watercourse or tributary? No ✓✓ Yes Describe length and characteristics of each conveyance pathway(s). property(ies). p I) Nrsft rn b(c — rye— t vib es OF V ER CA.l- Include C-V,_ ownership of 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 2008 Part 3 — Property Characteristics Continued (Page 3.4) Hydrologic Attributes of Subject Property (or Phase) (continued) Conveyance Pathways (continued) Do drainage easements exist for part of pathway(s)? No any If yes, for what part of length? (" S % Created by? 'plat, or instrument. If instrument(s), describe their provisions. I/Yes Pathway Areas Where runoff must cross lower properties, describe characteristics of abutting lower property(ies). (Existing watercourses? Easement or Consent aquired ?) 4(,1P' Nearby Drainage Facilities Describe any built or improved drainage facilities existing near the property (culverts, bridges, Tined channels, buried conduit, swales, detention ponds, etc). 2 - 2-.1 1A 0 C- V\? @ Cl e 5 ` l 44F — 1 - 4 - . Do any of design? thesyhave hydrologic or hydraulic influence on proposed stormwater No Yes If yes, explain: SECTION IX APPENDIX D - TECHNICAL DESIGN SUMMARY STORMWATER DESIGN GUIDELINES Page 9 of 26 APPENDIX. D: TECH. DESIGN SUMMARY Effective February 2007 As Revised February 2008 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. V Nt04 f 10 j ° 1R4•Xa- Discharge(s) To Lower Property(ies) (Section II, Paragraph El) Does project in ude drainage features (existing or future) proposed to become public via platting? V No Yes Separate Instrument? No Yes Per Guidelines reference above, how will runoff be discharged to neighboring property(ies)? — Establishing Easements (Scenario 1) 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 - development pre conditions (detention, sheet flow, partially concentrated, etc.). (Attached Exhibit # ) ?rc t t ••s Foi cic �1 e -(v t c - '1j F Syr,, 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)? 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 2008 Part 4 — Drainage Concept and Design Parameters Continued (Page 4.2) Stormwater Management Concept (continued) Within Project Area Of Multi -Phase Project Will project result in shifting runoff between Basins or between Watersheds? t✓ 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. c 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 Proiect Area (type & location of facilities): (Attached Exhibit # ) - Co — - GP-1:. 1 ' t\eeer( 1 b-a.tp 3. By phase (or site) proiect: Describe planned mitigation measures for phases (or sites) in subsequent questions of this Part. c- -0 Are aquatic echosystems proposed? No Yes In which phase(s) or project(s)? m } it U) C 01 y O O Are other Best Management Practices for reducing stormwater pollutants proposed? No Yes Summarize type of BMP and extent of use: co I 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 Duffel's 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 2008 Part 4 — Drainage Concept and Design Parameters Continued (Page 4.3) Stormwater Management Concept (continued) Within Project Area Of Multi -Phase Project (continued) / Will Project Area include bridge(s) or culvert(s)? No v Yes Identify type and general size and In which phase(s). 1 g" S6 {Le. P - Pe % C.,,51.-Jwve 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): scbt.c.ki ¶- cores -t (Pa errs W 4 U.- r■pe." Leo, -ct Within Or Serving Subject Property (Phase, or Site) If property part of larger Project Are, is design in substantial conformance with earlier analysis and report for larger area? es No, then summarize the difference(s): Identify whether each of the types of drainage features listed below are included, extent of use, and general characteristics. Typical shape? Surfaces? 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 w th B -CS Standard Specifications? Yes No, then explain: At intersections or otherwise, do valley gutters cross arterial or collector streets? 6 Yes If yes explain: eets with cL ptter use 10 Are valley gutters proposed to cross any street away from an intersection? o 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 2008 Part 4 — Drainage Concept and Design Parameters Continued (Page 4.4) Stormwater Management Concept (continued) Within Or Serving Subject Property (Phase, or Site) (continued o. t 1, c- a) D CD 5 -9 5 li5 _c 0 o co a) d a Will Q Gutter line slopes: Least 0 • te° f Usual el. Greatest Z5 - Are inlets recessed on arterial and collector streets? 'Yes No If "no ", identify where and why. Will inlets capture 10 -year deli tormflow 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. Sea curves: Are inlets placed at low points? Yes No Are inlets and condui�t sized to prevent 100 -year stormflow from ponding at greater than 24 inches? Yes No Explain no answers. 100 -yr stormflow be containefi. in combination of ROW and buried conduit on whole length of all streets? Yes No If no, describe where and why. Do degns for curb, gutter, and inlets comply with B -CS Technical Specifications? ‘/ Yes No If not, describe difference(s) and attach justification. M a } Are any 12 -inch laterals used? No Yes Identify length(s) and where used. Pipe runs between system access points (feet): Longest ' Typical 2 .0c '3.=. -� , N I • 0 E. Z v e Are junction boxes used at each bend? " Yes No If not, explain where and why. ° 0 — Are downstpam soffits at or below upstream soffits? Yes L/ No If not, explain where and why: Least amount that hydraulic grade line is below gutter line (system - wide): —6 r r SECTION IX APPENDIX D — TECHNICAL DESIGN SUMMARY STORMWATER DESIGN GUIDELINES Page 13 of 26 APPENDIX. D: TECH. DESIGN SUMMARY Effective February 2007 As Revised February 2008 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) Outfall(s) 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? /At — Zc nrW__ C c•Eo FPS 3) Watercourse (or system), velocity, and angle? For each outfall above, what measures are taken to prevent erosion receiving and all facilities at juncture? p 1 ) 1, 04 TO eaC. 62 ro -11Q P l- U 2) c.c T te r` t_-. 3) or scour of [ -b7 . Are swales used to drain streets? 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 2008 Part 4 — Drainage Concept and Design Parameters Continued (Page 4.6) Stormwater Management Concept (continued) Within Or Serving Subject Property (Phase, or Site) (continued) r Is . o d y v as 0 et Are roadside ditches used? No Yes If so, provide the following: 25 flow contained with 6 inches of freeboard throughout ? Yes No -year Are banks separated from road shoulders 2 feet or more? Yes No top of Are ditch trapezoidal and at least 1.5 feet deep? Yes No all sections For any "no" answers provide location(s) and explain: If conduit is beneath a swale, provide the following information (each instance). Instance 1 Describe general location, approximate length: as >- o Is 100 -year design flow contained in conduit/swale combination? Yes No If "no" explain: o o ` Z 2 I Ta 0 F. - -a a, m c T c c t U �- O 0 o w ca o E d . c .O -13 E a, a, w c v -- o iii c °- E a O a 0 m 13 C CO v S Inlets a, c 3 ° v, Space for 100 storm flow? ROW Easement Width -year Swale Surface type, minimum Conduit Type and size, minimum and maximum slopes, design storm: and maximum slopes: 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? Yes No If "no" explain: for 100 storm flow? ROW Easement Width Space -year Swale Surface type, minimum Conduit Type and size, minimum and maximum slopes, design storm: and maximum slopes: 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 2008 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 con it receive runoff from public ROW or easements? 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 1 4, etc. If swales are used in more than two instances, attach sheet providing all above information for each instance. Channel ' provements 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 2008 SECTION IX STORMWATER DESIGN GUIDELINES Effective February 2007 APPENDIX D - TECHNICAL DESIGN SUMMARY Part 4 — Drainage Concept and Design Parameters Continued (Page 4.8) Stormwater Management Concept (continued) Within Or Serving Subject Property (Phase, or Site) (continued) Existing channels (small creeks) : Are these used? No Yes If "yes" provide the information below. Will small creeks and their floodplains remain undisturbed? Yes No How many disturbance instances? Identify each planned location: For each location, describe length and general type of proposed improvement (including floodplain changes): For each location, describe section shape & area, flow line slope (min. & max.), surfaces, and 100 -year design flow. Watercourses (and tributaries): Aside from fringe changes, are Regulatory Watercourses proposed to be altered? No Yes Explain below. Submit full report describing proposed changes to Regulatory Watercourses. Address existing and proposed section size and shape, surfaces, alignment, flow line changes, length affected, and capacity, and provide full documentation of analysis procedures and data. Is full report submitted? Yes No If "no" explain: 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 maintenance space? Yes No If not, identify location(s) and explain: Page 17 of 26 APPENDIX. D: TECH. DESIGN SUMMARY As Revised February 2008 Part 4 — Drainage Concept and Design Parameters Continued (Page 4.9) Stormwater Management Concept (continued) Within Or Serving Subject Property (Phase, or Site) (continued) How many facilities for subject property project? / For each provide info. below. For each dry-type facilitiy: Faci ity 1 Faci ity 2 Acres served & design volume + 10% /t1 100-yr volume: free flow & plugged ? i 000 F Design discharge (10 yr & 25 yr) SC.G ( 7, 05' Spillway crest at 100-yr WSE? /'yes no yes no Berms 6 inches above plugged WSE? ryes no yes no Explain any "no" answers: For each facility what is 25 -yr design Q, and design of outlet structure? Facility 1: 4 5 JJ Facility 2: Do outlets and spillways discharge into a public facility in easement or ROW? Facility 1: . Yes No Facility 2: Yes No Are Detention Facilities Proposec 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 " Describe type and location: �vc 1L- —Be — 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 2008 SECTION IX APPENDIX D - TECHNICAL DESIGN SUMMARY Part 4 — Drainage Concept and Design Parameters Continued (Page 4.10) Stormwater Management Concept (continued) Within Or Serving Subject Property (Phase, or Site) (continued) Do structures comply with B -CS Specifications? Facility 1; Facility 2: r no, and explain if "no ": For additional facilities provide all same informat7on a separate sheet. Are parking areas to be used for detention? No Yes What is maximum depth due to required design storm? 0) rn 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: Part 4 — Drainage Concept and Design Parameters Continued (Page 4.11) Stormwater Management Concept (continued) Within Or Serving Subject Property (Phase, or Site) (continued) • more instances of any type describe location and same information on separate sheet) Named Regulatory Wateryourses (& 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, pd study findings design(s). Is report provided? -"Yes No A : ' al or Maior Collector Streets: Will culverts lerve t e types of roadways? For each identify the • Yes How many instances? location an • • ovide the information below. Instance 1: Gc. - -. vL A1/4.3- flD•, r. Jtv. Instance 2: Instance 3: Yes or No for the 100 -ye- design flow: 1 2 3 Headwater WSE 1 • •t below lowest curb top? i Spread of he - • - ter within ROW or easement? Is velocity limited per conditions (Table C -11)? te Explain any "no" answer(s): Minor Collector or Local Streets: Will culverts serve these 1 types of streets? for each identify the No f Yes How many instances? location and provide the information below: Instance 1: c.,.. pil N CvLvG f 12- 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? `1 100 -yr. max. depth at street crown 2 feet or less? Y Product of velocity (fps) & depth at crown (ft) _ ? af.6 Is velocity limited per conditions (Table C -11)? 'i Limit of down stream analysis (feet)? Explain any "no" answers: SECTION IX APPENDIX D - TECHNICAL DESIGN SUMMARY STORMWATER DESIGN GUIDELINES Page 20 of 26 APPENDIX. D: TECH. DESIGN SUMMARY Effective February 2007 As Revised February 2008 SECTION IX STORMWATER DESIGN GUIDELINES Effective February 2007 APPENDIX D - TECHNICAL DESIGN SUMMARY Part 4 — Drainage Concept and Design Parameters Stormwater Management Concept (continued) Within Or Serving Subject Property (Phase, or Site) (continued) Continued (Page 4.12) All Proposed Culverts: For all proposed culvert facilities (except driveway /roadside ditch intersects) provide information requested in next eight boxes. Do culverts and travelways intersect at 90 degrees? ./ Yes No If not, identify location(s) and intersect angle(s), and justify the design(s): Does drainage way alignmgnt change within or near limits of culvert and surfaced approaches thereto? i'// No Yes If "yes" identify location(s), describe change(s), and justification: Are flumes or conduit to discharge into culvert barrel(s)? ` No Yes If yes, identify Iocation(s) and provide justification: Are flutes or conduit to discharge into or near surfaced approaches to culvert ends? • No Yes If "yes" identify Iocation(s), describe outfall design treatment(s): Is scour /erosion protection provided to ensure for 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 bacter be fully contained in street ROW, and /or drainage easements/ ROW? Yes No if not, why not? Do appreciable hydraulic effects of any culvert extend downstror upstream to neighboring land(s) not encompassed in subject property? No Yes If `yes" describe Iocation(s) and mitigation measures: Are aleulvert designs and materials in compliance with B -CS Tech. Specifications? Y No If not, explain in Special Design Section of this Part. Page 21 of 26 APPENDIX. D: TECH. DESIGN SUMMARY As Revised February 2008 Part 4 — Drainage Concept and Design Parameters Continued (Page 4.13) Stormwater Management Concept (continued) Within Or Serving Subject Property (Phase, or Site) (continued) / 1) v 0) m Is a bridge included in If "yes" provide the following plans for subject property project? v 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 A' To a i m 0 Is a Stormwater Pollution Prevention Plan (SW3P) established for project construction? No VYes Provide a general description of planned techniques: Special Designs — Non - Traditional Methods Are any non - traditional methods replic on, BMPs for water quality, 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 substantial that stormwater management st will not exceed those of traditional Yes No If "no" explain: for use and objectives will not design SECTION IX STORMWATER DESIGN GUIDELINES Page 22 of 26 APPENDIX. D: TECH. DESIGN SUMMARY As Revised February 2008 APPENDIX D - TECHNICAL DESIGN SUMMARY Effective February 2007 SECTION IX STORMWATER DESIGN GUIDELINES Effective February 2007 APPENDIX D - TECHNICAL DESIGN SUMMARY Page 23 of 26 APPENDIX. D: TECH. DESIGN SUMMARY As Revised February 2008 Part 4 — Drainage Concept and Design Parameters I Continued (Page 4.14) Stormwater Management Concept (continued) Within Or Serving Subject Property (Phase, or Site) (continued) Special Designs — Deviation From B-CS Technical Specifications If any design(s) or material(s) of traditional runoff - handling facilities deviate from provisions of B -CS , hnical Specifications, check type facility(ies) and explain by specific detail element. Drain system elements Channel features /, , - ntion elements Swales Ditches Inlets Outfalls Culvert features 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 Drainage Areas provided? Yes No Is a map(s) showing all Design Briefly summarize the range of applications made of the Rational Formula: What is the size and location of largest Design Drainage Area to which the Rational Formula has been applied? ^-." 3 acres Location (or identifier): ,1 SECTION IX STORMWATER DESIGN GUIDELINES Effective February 2007 APPENDIX D - TECHNICAL DESIGN SUMMARY Page 23 of 26 APPENDIX. D: TECH. DESIGN SUMMARY As Revised February 2008 Part 4 — Drainage Concept and Design Parameters Continued (Page 4.15) Design Parameters (continued) Hydrology (continued) In making deter ations for time of concentration, was segment analysis used? No Yes In approximately what Design h '° percent of Drainage Areas? % As to intensity- duration- frequency and rain depth criteria for deter�r fining runoff flows, were any criteria other than those provided in these Guidelines used? No Yes If "yes" identify type of data, source(s), and where applied: For each of the stormwater management features listed below identify the storm return frequencies (year) analyzed (or checked), and that used as the basis for design. Feature Analysis Year(s) Design Year Storm drain system for arterial and collector streets Storm drain system for local streets l'D i o 0 Open channels Swale /buried conduit combination in lieu of channel Swales Roadside ditches and culverts serving them Detention facilities: spillway crest and its outfall 2S /0 0 Detention facilities: outlet and conveyance structure(s) 1V 2 ..5". / o n Detention facilities: volume when outlet plugged l ot> / 0® Culverts serving private drives or streets Culverts serving public roadways ZS- / o cp Bridges: provide in bridge report. Hydraulics What is the range of design flow velocities as outlined below? Design flow velocities; Gutters Conduit Culverts Swales Channels Highest (feet per second) 2..5 r7 69. (o7 ze. 2.1 Lowest (feet per second) 2. 2 cp 5-7S `' 24 Streets and Storm Drain Systems Provide the summary information outlined below: Roughness coefficients used: For street gutters: O of € For conduit t y p e ( s ) Z Q . P 0.013 i ° 5 O f (Z Coefficients: SECTION IX APPENDIX D — TECHNICAL DESIGN SUMMARY STORMWATER DESIGN GUIDELINES Page 24 of 26 APPENDIX. D: TECH. DESIGN SUMMARY Effective February 2007 As Revised February 2008 Part 4 — Drainage Concept and Design Parameters l Continued (Page 4.16) Design Parameters (continued) Hydraulics (continued) Street and Storm Drain Systems (continued) For the following, are assumptions other than allowable per Guidelines? Inlet coefficients? '/ No Yes Head and friction losses 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? For 100 -year flow conditions? Yes No Explain any v Yes No "no" answers: What tailwater conditions were assumed at outfall point(s) of the storm drain system? each location and explain: t k t. C — tb ai t Z t�a.� Identify 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? f ie-c— Pt s — Entrance, friction and exit losses: Bridges Provide all in bridge report SECTION IX STORMWATER DESIGN GUIDELINES Effective February 2007 APPENDIX D - TECHNICAL DESIGN SUMMARY Page 25 of 26 APPENDIX. D: TECH. DESIGN SUMMARY As Revised February 2008 SECTION IX STORMWATER DESIGN GUIDELINES Effective February 2007 APPENDIX D - TECHNICAL DESIGN SUMMARY Part 4 — Drainage Concept and Design Parameters I 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 CJ 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 State of Texas PE No. 1S SE33 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 8 was prepared by me (or under my supervision) in accordance with provisions of the Bryan/College Station Unified Drainage Design Guidelines for the owners of the property. All licenses and permits required by any and all state and federal regulatory agencies for th proposed drainage improvements have been issued or fall under applicable general , � / � (Affix J 5 'c r` �F r , . ��1 � Licensed Professional Engineer 1 * • • • • j'�' ma ALF %� i :: _ ■ • . N I 4 / l i `z- / , __ L' ,�P APPEN XI a D ESIGN SUMMARY As Revised February 2008 Page 26 of 26