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HomeMy WebLinkAboutTechnical Design SummarySECTION 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 10 1 2LD • ID ar 40 SECTION IX APPENDIX D - TECHNICAL DESIGN SUMMARY or clearing /grading permits, as well as reference to any application numbers or codes assigned by the City to such request. 3. The location of the project should be described. This should identify the Named Regulatory Watershed(s) in which it is located, how the entire project area is situated therein, whether the property straddles a watershed or basin divide, the approximate acreage in each basin, and whether its position in the Watershed dictates use of detention design. The approximate proportion of the property in the city limits and within the ETJ is to be identified, including whether the property straddles city jurisdictional lines. If any portion of the property is in floodplains as described in Flood Insurance Rate Maps published by FEMA that should be disclosed. 4. The hydrologic characteristics of the property are to be described in broad terms: existing land cover; how and where stormwater drains to and from neighboring properties; ponds or wetland areas that tend to detain or store stormwater; existing creeks, channels, and swales crossing or serving the property; all existing drainage easements (or ROW) on the property, or on neighboring properties if they service runoff to or from the property. 5. The general plan for managing stormwater in the entire project area must be outlined to include the approximate size, and extent of use, of any of the following features: storm drains coupled with streets; detention / retention facilities; buried conveyance conduit independent of streets; swales or channels; bridges or culverts; outfalls to principal watercourses or their tributaries; and treatment(s) of existing watercourses. Also, any plans for reclaiming land within floodplain areas must be outlined. 6. Coordination and permitting of stormwater matters must be addressed. This is to include any specialized coordination that has occurred or is planned with other entities (local, state, or federal). This may include agencies such as Brazos County government, the Brazos River Authority, the Texas A &M University System, the Texas Department of Transportation, the Texas Commission for Environmental Quality, the US Army Corps of Engineers, the US Environmental Protection Agency, et al. Mention must be made of any permits, agreements, or understandings that pertain to the project. 7. Reference is to be made to the full drainage report (or the Technical Design Summary Report) which the executive summary represents. The principal elements of the main report (and its length), including any maps, drawings or construction documents, should be itemized. An example statement might be: "One -page drainage report dated , one set of construction drawings ( sheets) dated , and a -page specifications document dated comprise the drainage report for this project." STORMWATER DESIGN GUIDELINES Page 2 of 26 APPENDIX. D: TECH. DESIGN SUMMARY Effective February 2007 As Revised February 2009 Part 2 — Project Administration Start (Page 2.1) Engineering and Design Professionals Information Engineering Firm Name and Address: Jones & Carter, Inc. 1716 Briarcrest Drive, Suite 160 Bryan, Texas 77802 Jurisdiction City: Bryan X College Station Date of Submittal: Lead Engineer's Name and Contact Info.(phone, e-mail, fax): Steve E. Duncan, P.E. (979) 731 -8000 SDuncan @jonescarter.com Fax: (979) 846 -2893 Other: Supporting Engineering / Consulting Firm(s): Derek Walton Jones & Carter, Inc. DWalton@jonescarter.com Other contacts: Developer / Owner / Applicant Information Developer / Applicant Name and Address: Titan Valley Park, Limited Partnership C/O Southcorp Realty Advisors, Inc. 3401 Allen Parkway, Suite 200, Houston, Texas 77019 Phone and e-mail: 713- 960 -1880 DHillman @southcorprealty.com Property Owner(s) if not Developer / Applicant (& address): Phone and e-mail: Project Identification Development Name: Valley Park Center 2 Is subject property a site project, a single -phase subdivision, or part of a multi -phase subdivision? Valley Park Center If multi - phase, subject property is phase 2 of 3 . Legal description of subject property (phase) or Project Area: (see Section II, Paragraph B -3a) Valley Park Center, Phase 2 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. Phase I: Completely Developed General Location of Project Area, or subject property (phase): Northwest Corner of Highway 60 and FM 2818 In City Limits? Bryan: acres. Extraterritorial Jurisdiction (acreage): Bryan: College Station: Acreage Outside ETJ: College Station: 11.635 acres. SECTION IX STORMWATER DESIGN GUIDELINES Effective February 2007 APPENDIX D - TECHNICAL DESIGN SUMMARY Page 3 of 26 APPENDIX. D: TECH. DESIGN SUMMARY As Revised February 2009 Part 2 — Project Administration Continued (page 2.2) Project Identification (continued) Roadways abutting or within Project Area or subject property: Hwy 60 FM 2818 Abutting tracts, platted land, or built developments: City Cemetary (West) Named Regulatory Watercourse(s) & Watershed(s): Tributary Basin(s): Plat Information For Project or Subject Property (or Phase) Preliminary Plat File #: Final Plat File #: Date: Status and Vol /Pg: OPRISC: VOL. 7675, PAGE 282 Name: If two plats, second name: File #: Status: N/A Date: Zoning Information For Project or Subject Property (or Phase) Zoning Type: C1 (Phase II) Existing or Proposed? Exisiting 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): N/A Participants: N/A Preliminary Report Required? Yes Submittal Date 1/27/2010 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. N/A SECTION IX STORMWATER DESIGN GUIDELINES Effective February 2007 APPENDIX D - TECHNICAL DESIGN SUMMARY Page 4 of 26 APPENDIX. D: TECH. DESIGN SUMMARY 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: N/A 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 X No Summarize need(s) & actions taken (include contacts & dates): Storm Permit Approved, will deliver approved permit to city of College Station. Coordination with TAMUS Needed? Yes No X Summarize need(s) & actions taken (include contacts & dates): Permits For Pro 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 X Yes ___ US Environmental Protection Agency No X Yes ___ Texas Commission on Environmental Quality No X Yes Brazos River Authority No X Yes ___ SECTION IX STORMWATER DESIGN GUIDELINES Effective February 2007 APPENDIX D - TECHNICAL DESIGN SUMMARY Page 5 of 26 APPENDIX. D: TECH. DESIGN SUMMARY 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? 11.635 Acres Total. Phase I = 4.655 Acres / II = 1.379 / III = 2.439/ IV = 2.862 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. X 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 Tots. 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 projects: building use(s), approximate floor space, impervious cover ratio. Subdivisions: number of lots by general type of use, linear feet of streets and drainage easements or ROW. Phase I = 54,000 SF 88.40 Phase 11 = 25,000 SF 83.40 Phase III = 45,000 SF 76.60 Project Is any work planned on land that is not platted If yes, explain: Land is platted, but we will be filing a replat or on land for which platting is not pending? X No Yes FEMA Floodplans 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 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 STORMWATER DESIGN GUIDELINES Effective February 2007 APPENDIX D — TECHNICAL DESIGN SUMMARY Page 6 of 26 APPENDIX. D: TECH. DESIGN SUMMARY 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. The design subject to approval, will ultimately control the release rate for Valley Park Center at full development. Do existing topographic features on subject property store or detain Describe them (include approximate size, volume, outfall, model, etc). At Phase I, a temporary detention pond was constructed on Lot 3. runoff? No X 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. Detention not required. _X If the need for Type 1 Detention must be evaluated: What decision has been reached? By whom? How was determination made? SECTION IX STORMWATER DESIGN GUIDELINES Effective February 2007 APPENDIX D - TECHNICAL DESIGN SUMMARY Page 7 of 26 APPENDIX. D: TECH. DESIGN SUMMARY 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 Flow determination: Outline hydrologic methods and assumptions: 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 Most likely no changes expected. The entire west property line of the adjoining property is the recently constructed city cemetary. 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). Property immediately discharges into an approved TxDOT stormwater facility. SECTION IX STORMWATER DESIGN GUIDELINES Effective February 2007 APPENDIX D - TECHNICAL DESIGN SUMMARY Page 8 of 26 APPENDIX. D: TECH. DESIGN SUMMARY As Revised February 2009 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)? 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 ?) N/A Nearby Drainage Facilities Describe any built or improved drainage facilities existing near the property (culverts, bridges, lined channels, buried conduit, swales, detention ponds, etc). TxDOT Facility Do any of design? The TxDOT Park Detention these have hydrologic or hydraulic influence on proposed stormwater No X Yes If yes, explain: stormwater inlet located in the 2818 ROW is the discharge point for the Valley Pond SECTION IX STORMWATER DESIGN GUIDELINES Effective February 2007 APPENDIX D - TECHNICAL DESIGN SUMMARY Page 9 of 26 APPENDIX. D: TECH. DESIGN SUMMARY As Revised February 2009 Part 4 — Drainage Concept and Design Parameters Start (Page 4.1) S tormwater 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? 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 # ) Detention - Please refer to attached drainage report. 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 X Yes Explain and provide documentation. TxDOT has updated the existing permit 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) Stormwater Management Concept (continued Within Project Area Of Multi -Phase Project Will project result in shifting runoff between Basins or between Watersheds? X 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 X 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 # ) N/A 2. For Overall Project Area (type & location of facilities): (Attached Exhibit # ) Detention Pond. Southeast corner of Property 1.00 Acres / 11.635 Total Acres. 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 _X project(s)? Are other Best Management Practices for reducing stormwater pollutants proposed? X 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 Ouffalls 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 Desiqn 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)? general size and In which phase(s). X No Yes Identify type and 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): Detention pond will will be constructed on lot 4 in conjunction with Phase 2. Additionally 100% of the underground storm drain conduit system will be installed in conjunction with the construction work for Phase 2. Within Or Serving Subject Property (Phase, or Site) If property and report part of larger Project Area, is design in substantial for larger area? X Yes No, then conformance with earlier analysis summarize the difference(s): Identify whether each of the types of drainage features listed below are included, extent of use, and general characteristics. Are roadside ditches used? >C No Yes Typical shape? Surfaces? Steepest side slopes: Usual front s opes: Usual back slopes: Flow line slopes: least Typica distance (Attached from travelway: Exhibit # ) typical greatest Are longitudinal culvert ends Yes No, then in compliance with B -CS Standard Specifications? explain: Are streets with curb and gutter used? _z__ No Yes At intersections or otherwise, No Yes If do valley gutters cross arterial or collector streets? yes explain: Are valley gutters proposed No Yes Explain: to cross any street away from an intersection? (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? No x Yes Are any 12 -inch laterals used? X_ No Yes Identify length(s) and where used. Pipe runs between system access points (feet): Typical 220 + /- Longest 267 Are junction boxes used at each bend? X 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): 0.91' _x__ 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 r Serving Subject Property (Phase, or Site) (continued) Storm drain system (continued) (on separate sheet provide same info. for more instances) (s)Ileftn0 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? Design Discharge Velocity = 7.49 cfs Angle between converging flow lines = no angle, in line with upstream. 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) Provide concrete paved channel below outfall opening. (Through Det. Pond) 2) 3) Are swales used to drain streets? _z__ No Yes Are swale(s) situated along property lines between properties? No Yes _X 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: (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? ____ Yes ____ No If "no" explain: 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? __x____ 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? __,X___ 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) Stormwater Management Concept (continued) Within Or Serving Subject Property (Phase, or Site) (continued) How many facilities for subject property project? __ 1 __ For each provide info. below. For each dry -type facilitiy: Faci ity 1 Faci ity 2 Acres served & design volume + 10% 11.635 12.799 100 -yr volume: free flow & plugged 3.3 AC -FT 4.0 AC -FT Design discharge (10 yr & 25 yr) 19.2 22.1 Spillway crest at 100 -yr WSE? Berms 6 inches above plugged WSE? X yes no yes no X yes no yes no ____ ____ Explain any "no" answers: For each facility what is 25 -yr design Q, and design of outlet structure? Facility 1: 22.1 cfs; Outlet Structure is a combination of round conduits combining at adjacent manhole Facility 2: Do outlets and spillways discharge into a public facility in easement or ROW? Facility 1: X 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: 7.49 ft/s & n/a Facility 2: & Are energy dissipation measures used? No X_ Yes Describe type and _ location: At TxDOT Facility Enterance For each, is spillway surface treatment other than concrete? Yes or no, and describe: Facility 1: Yes (Grass lined spillway) Facility 2: For each, what measures are taken to prevent erosion or scour at receiving facility? Facility 1: RIP RAP, concrete pilot channel Facility 2: If berms are used give heights, slopes and surface treatments of sides. Facility 1: 4:1 Side Slopes / Grass with plants 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; Yes Facility 2: For additional facilities provide all same information on a separate sheet. Are parking areas to be used for detention? X No Yes What is maximum depth due to required design storm? Are culverts used at private crossings? No ____ Yes Roadside Ditches: Will culverts serve access driveways at roadside ditches? X 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 Major 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) 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? _ identify location(s) and intersect angle(s), and justify the design(s): Yes No If not, 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 components, and surfacing at culvert ends? Yes ____ of culvert structural 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) Stormwater Management Concept (continued) Within Or Serving Subject Property (Phase, or Site) (continued) Bridge(s) Is a bridge included in plans If "yes" provide the following for subject property project? 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) (structural, geotechnical, hydrologic, and hydraulic factors) must accompany this summary report. Is the report provided? ____ Yes ____ No If "no" explain: Water Quality Is a Stormwater Pollution Prevention Plan (SW3P) established for project construction? X No Yes Provide a general description of planned techniques: Please refer to grading and erosion control plan Special Designs — Non - Traditional Methods Are any replication, X No non - traditional methods (aquatic echosystems, wetland -type detention, natural stream BMPs for water quality, etc.) proposed for any aspect of subject property project? ____ Yes If "yes" list 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? N/A 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 Page 22 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 4.14) 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 B -CS Technical Specifications, check Detention elements traditional runoff - handling facilities deviate from provisions of type facility(ies) and explain by specific detail element. Drain system elements Channel features 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 Is a map(s) showing all Design Drainage Areas provided? X Yes No Briefly summarize the range of applications made of the Rational Formula: 100 What is the size and location of largest has been applied? acres Design Drainage Area to which the Rational Formula Location (or identifier): 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 2009 Part 4 — Drainage Concept and Design Parameters Continued (Page 4.15) Design Parameters (continued) Hydrology (continued) In making determinations for time of concentration, was segment analysis used? ____ No X 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 Storm drain system for local streets Open channels Swale /buried conduit combination in lieu of channel Swales Roadside ditches and culverts serving them Detention facilities: spillway crest and its outfall 2, 10, 25, 100 100 Detention facilities: outlet and conveyance structure(s) 2, 10, 25, 100 All Detention facilities: volume when outlet plugged 100 100 Culverts serving private drives or streets Culverts serving public roadways 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) 11.04 ft /s Lowest (feet per second) 6.06 ft /s Streets and Storm Drain Systems Provide the summary information outlined below: Roughness coefficients used: For street gutters: For conduit type(s) DpE Coefficients: 0.012 SECTION IX STORMWATER DESIGN GUIDELINES Effective February 2007 APPENDIX D - TECHNICAL DESIGN SUMMARY Page 24 of 26 APPENDIX. D: TECH. DESIGN SUMMARY As Revised February 2009 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: The submerged tailwater conditions results in a slightly slower velocity Yes X No X Yes ____ No at pond outlet. Are hydraulic grade lines calculated and shown for design storm? For 100 -year flow conditions? X__ Yes No Explain any X__ Yes No "no" answers: What tailwater conditions were assumed at outfall point(s) of the storm drain system? Identify each location and explain: The 48" outfall into the pond; assumed submerged conditions existed. 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 Effective February 2007 APPENDIX D - TECHNICAL DESIGN SUMMARY Page 25 of 26 APPENDIX. D: TECH. 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 HEC - HMS 3.3 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: Please see attached Drainage Report Dated 04/08/2010 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 B was prepared by me (or under my supervision) in accordance with provisions of the Bryan /College Station Unified Drainage Design Guidelines for the owners of the property. All licenses and permits required by any and all state and federal regulatory agencies for Vik drainage improvements have been issued or fall under applicable general s�F.TEx ��t I' ro * .4 1 i -- --- ___Wo__ I * i Licensed Professional Engineer NC STEVE E. DU ' .. � j•,o: • 8325..2N: : R.J 14)'.. State of Texas PE No. 83252 z / C E NS . $ �, .. t. A.r_ _.C SECTION IX STORMWATER DESIGN GUIDELINES Page 26 of 26 APPENDIX. D: TECH. DESIGN SUMMARY APPENDIX D - TECHNICAL DESIGN SUMMARY Effective February 2007 As Revised February 2009