HomeMy WebLinkAboutDrainage Report •
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• Drainage Report
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• Meadowcreek Subdivision
• Phase 4B
• Brazos County, Texas
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• October, 2011
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• Developer:
BCS Development Company
• 4090 S. Highway 6, South
• College Station, Texas 77845
• (979) 690 -1222
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• Prepared By:
, LLC
Schultz Engineerin
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• TBPE Firm No. 12327
• P.O. Box 11995
• College Station, TX 77842
• 2730 Longmire Drive, Suite A
• College Station, Texas 77845
(979) 764 -3900
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• Drainage Report - Executive Summary
• Meadow Creek Subdivision, Phase 4B
• Brazos County, Texas
October 24, 2011
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• ENGINEER
SCHULTZ ENGINEERING, LLC.
• P.O. Box 11995
• College Station, Texas 77842
• Phone/Fax: (979) 764 -3900
• OWNER/DEVELOPER
• BCS Development Company
4090 S. Highway 6, South
College Station, Texas 77845
• (979) 690 -1222
• GENERAL DESCRIPTION AND LOCATION
• This project consists of the development of Phase 4B of the Meadow Creek Subdivision in
• Brazos County. Phase 4B is a single - family residential development, which will include the
construction of utilities and infrastructure.
• Phase 4B is located to the south of Phase 4A of the Meadow Creek development. The
development is located west of FM 2154 along the south side of Koppe Bridge Road
• approximately 1 mile from Wellborn, Texas.
• Area: 7.54 acres
• Existing Land Use: Vacant
Proposed Land Use: Single - Family Residential
• Number of Lots: 38 residential
• Drainage Basin: Peach Creek Drainage Basin
FEMA FIRM: #48041CO200-C, dated July 2, 1992
• F000dplain: None of this phase of the development lies within the floodplain.
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• HYDROLOGIC CHARACTERISTICS
The existing site was cleared in 2005. The elevations range from 306 to 320, sloping in generally
• southerly direction, where runoff leaves the site in an existing drainage channel which flows into
• the existing detention facilities. Ultimately, this runoff flows into a tributary of Peach Creek
• and then into Peach Creek.
• GENERAL STORMWATER PLAN
• The drainage plan for this development will involve the installation of additional pipes & inlets,
• which will collect and transmit the runoff into Detention Pond 2A. The runoff that is collected by
• the existing detention ponds will be discharged into a tributary of Peach Creek, which will flow
• into Peach Creek.
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• Page 1 of 3
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411 COORDINATION & STORMWATER PERMITTING
The project will require that a Notice of Intent be submitted to the Texas Commission for
Environmental Quality. No other permits are anticipated for this project.
DRAINAGE DESIGN
• General Information: Stormwater runoff from Phase 4B of the subdivision will be collected by
- a storm sewer system and will ultimately discharge into a tributary of
Peach Creek. The location of the drainage areas for evaluation of the
gutter depth check, inlet sizing and pipe evaluation are shown on Exhibit
• A. Also shown are the location of the inlets and storm sewer pipes.
Street Design: Standard cross - section (3% cross - slope, 27' B -B residential)
Lay down curb & gutter on residential streets
• Asphalt pavement
Standard recessed curb inlets (10' in length)
T Methodology: TR 55
• T Minimum 10 minutes
Design Storm Event: 10 -year - residential street & storm sewer
Pipe Materials: Corrugated HDPE w /smooth interior
• RCP, Profile Gasket in accordance with ASTM C443, ASTM C76, Class
• III
Manning's n Value: 0.013
Runoff Coefficients: 0.60 for developed lots
• Design Constraints: Max. water depth in curb = 4.0 in. or 0.33 ft.
Min. flow velocity = 2.5 fps
Max. flow velocity = 15 fps
• 100 -yr storm runoff maintained within the ROW (3 inches above curb)
25% Reduction in cross - sectional area of pipes less than 27" in diameter
• Design Software: Excel spreadsheets, AutoCad Hydraflow Express, StormCAD
This software was used to compute pipe capacity, flowrate and velocity
through each pipe, and determine hydraulic grade line elevations at each
• inlet or junction box. All of this information is shown in the summary
tables in the appendices.
The requirement for a 25% reduction in cross - sectional area of pipes less
• than 27" diameter is achieved by using internal pipe diameters that are
less than the standard diameter. The 24" diameter pipe areas were
reduced by 25% and a 20.6" diameter pipe used in the analysis and the
• 18' diameter pipe areas were reduced by 25% and a 15.6" diameter pipe
was in the analysis.
• Design Results The data presented in the Appendices indicates the gutter depth, inlet
- sizing and pipe sizes are in accordance with the requirements of the
design guidelines.
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• Page 2 of 3
Detention Analysis &
a Verification with
Previous Designs: The stormwater runoff from The Meadow Creek Subdivision was
- previously studied and detention ponds were designed for the entire
development including this phase.
• Applicable Exhibits: Exhibit A — Drainage Area Map
Appendix A — Drainage Area Calculations
Appendix B — Depth of Flow in Gutter
- Appendix C — Storm CAD Pipe & Inlet Analysis
• Appendix D — Technical Design Summary
- CONCLUSION The storm sewer drainage system in Phase 4B of The Meadow Creek
Subdivision will function within the requirements and restrictions of the
BCS Drainage Design Guidelines.
CERTIFICATION
- I, Joseph P. Schultz, Licensed Professional Engineer No. 65889, State of Texas, certify that this report for
• the storm sewer drainage design for The Meadow Creek Subdivision, Phase 4B was prepared by me in
• accordance with the provisions of the Unified Stormwater Design Guidelines.
0 1►l404 % , /
VI of tfr, z cs OF /474. -
1 * ' .. ' * Josep -' P. S hultz, P.E.
JOSEPH P. SCHULTZ
65889
y 111 • " • f urZG -v1
- F -12327
SCHULTZ ENGINEERING, LLC.
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Page 3 of 3
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w APPENDIX A
• Drainage Area Calculations
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• APPENDIX B
• Depth of Flow in Gutter Calculations
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Meadowcreek Subdivision
• Phase 4B
• Depth of Flow in Gutter
(Refer to Exhibit A for Gutter Locations)
• 10 -year storm 100 -year storm
Gutter A Slope t do Qio 1'10-actual 1 100 QIoo Two
• Location - Area # (acres) C ( ft/ft) (min) (in /hr) (cfs) (ft) (in) (in /hr) (cfs) (ft) (in)
- B3 <11 0.19 0.55 0.0124 10 8.635 0.90 0.162 1.95 11.639 1.22 0.181 2.18
• B4 <11 0.13 0.55 0.0124 10 8.635 0.62 0.141 1.69 11.639 0.83 0.157 1.89
• C1 <4 1.45 0.55 0.0080 22.6 5.809 4.63 0.325 3.90 7.901 6.30 0.365 4.38
• C2 5 1.26 0.55 0.0200 11.9 8.014 5.55 0.293 3.52 10.817 7.50 0.328 3.93
C3 4 2.09 0.55 0.0200 24.6 5.539 6.37 0.308 3.70 7.544 8.67 0.346 4.16
• C4 5A 1.21 0.55 0.0100 13.8 7.487 4.98 0.320 3.84 10.120 6.74 0.359 4.30
C5 4A 0.50 0.55 0.0100 10 8.635 2.37 0.243 2.91 11.639 3.20 0.271 3.26
IIII C6 <12 0.39 0.55 0.0080 10 8.635 1.85 0.230 2.77 11.639 2.50 0.258 3.09
• C15 6 1.15 0.55 0.0100 13.8 7.487 4.74 0.314 3.77 10.120 6.40 0.352 4.22
C16 6A 0.93 0.55 0.0080 14.3 7.362 3.77 0.301 3.61 9.954 5.09 0.337 4.04
• C17 11 0.55 0.55 0.0080 10 8.635 2.61 0.262 3.15 11.639 3.52 0.293 3.52
11111 D1 7 0.54 0.55 0.0300 10 8.635 2.56 0.203 2.44 11.639 3.46 0.227 2.73
• D2 9 0.07 0.55 0.0300 10 8.635 0.33 0.094 1.13 11.639 0.45 0.106 1.27
D3 8 1.26 0.55 0.0200 27.1 5.240 3.63 0.250 3.00 7.148 4.95 0.281 3.37
• D4 10 0.04 0.55 0.0200 10 8.635 0.19 0.083 0.99 11.639 0.26 0.092 1.11
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- Transverse (Crown) slope ( ft/ft)
In 27' street = 0.0300
• Straight Crown Flow (Solved to find actual depth of flow in putter, y):
• Q= 0.56 *(z /n) * S v2 * y = {Q /[0.56 *(z /n) *S 112] }318
• n = Roughness Coefficient = 0.018
S = Street/Gutter Slope (ft/ft)
• y = Depth of flow at inlet (ft)
z = Reciprocal of crown slope:
le
27' street = 33
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APPENDIX C
• Storm CAD Pipe & Inlet Analysis
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• APPENDIX D
• Technical Design Summary
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SECTION IX
• APPENDIX D - TECHNICAL DESIGN SUMMARY
- The Cities of Bryan and College Station both require storm drainage design to follow these
Is 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
f questions (affirmative or negative) and provide, at minimum, the information prescribed in the
• "Technical Design Summary" in this Appendix.
II 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
III 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.
II
ID 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
II • Part 6 — Conclusions and Attestation
• STORMWATER MANAGEMENT TECHNICAL DESIGN SUMMARY REPORT
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• Part 1 — Executive Summary
This is to be a brief prose report that must address each of the seven areas listed below.
Ill Ideally it will include one or more paragraphs about each item.
ID 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
ID Effective February 2007 As Revised February 2009
ID
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• SECTION IX
• APPENDIX D - TECHNICAL DESIGN SUMMARY
IIIII
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
IIII -page specifications document dated comprise
t he drainage report for this project."
-
-
-
-
-
-
• STORMWATER DESIGN GUIDELINES Page 2 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
• Effective February 2007 As Revised February 2009
ID
119
•
•
• SECTION IX
• APPENDIX D - TECHNICAL DESIGN SUMMARY
Part 2 — Proiect Administration Start (Page 2.1)
. _ Engineering and' Desi n Professionals Information .'
Engineering Firm Name and Address: Jurisdiction
• Schultz Engineering, LLC City: Bryan
• P.O. Box 11995 ✓ College Station
College Station, Tx 77842 Date of Submittal:
October 2011
• Lead Engineer's Name and Contact Info.(phone, e fax): Other:
• Joseph P. Schultz, PE email: joeschultz840verizon.net
Phone: 764 -3900 fax: 764 -3910
• Supporting Engineering / Consulting Firm(s): Other contacts:
• N/A
•
. NwDeveloper / Owner / Applicant Information
• Developer / Applicant Name and Address: Phone and e-mail:
BCS Development Company
4090 S. Highway 6, South
• College Station, Tx 77845
Property Owner(s) if not Developer / Applicant (& address): Phone and e
same as Developer N/A
• Project Identification
• Development Name: Meadow Creek Subdivision, Phase 4B
• Is subject property a site project, a single -phase subdivision, or part of a multi -phase subdivision?
• Multi If multi - phase, subject property is phase 4B of 5 .
• Legal description of subject property (phase) or Project Area:
• (see Section II, Paragraph B -3a)
• Samuel Davisdon League, A -13 - 7.54 Acres
•
•
If subject property (phase) is second or later phase of a project, describe general status of all
• earlier phases. For most recent earlier phase Include submittal and review dates.
All previous phases are complete. The most recent phase, 4A, was submitted and approved in 2009.
•
•
General Location of Project Area, or subject property (phase):
•
• In City Limits? Extraterritorial Jurisdiction (acreage):
• Bryan: acres. Bryan: College Station:
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
•
•
•
•
SECTION IX
• APPENDIX D — TECHNICAL DESIGN SUMMARY
Part 2 — Project Administration Continued (page 2.2)
• la Project Identification (continued) j
ED Roadways abutting or within Project Area or Abutting tracts, platted land, or built
subject property: developments:
• Meadow Creek Subdivision - Phase 4A (9491/126) to
• the north
i Named Regulatory Watercourse(s) & Watershed(s): Tributary Basin(s):
• None
y Plat,lnformation'For Projector Subiect Property (or Phase)
•
• Preliminary Plat File #: 0900500023 Final Plat File #: - Date: -
lb Name: Meadow Creek Subdivision Status and VoI /Pg:
• If two plats, second name: N/A File #:
• Status: Date:
• Zoning lriformation For Projector Subject Property (or Phase)
Zoning Type: Existing or Proposed? 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): Participants:
N/A
-
•
Preliminary Report Required? N/A Submittal Date Review Date
• Review Comments Addressed? Yes N/A 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.
111
11111
• 111
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 — Proiect 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
Dept. Contact: Date: Subject:
With Other
- Departments of
Jurisdiction
City (Bryan or
• College Station)
Coordination With Summarize need(s) & actions taken (include contacts & dates):
Non jurisdiction
City Needed?
• Yes No ✓
• Coordination with Summarize need(s) & actions taken (include contacts & dates):
Brazos County
Needed?
- Yes No
Coordination with Summarize need(s) & actions taken (include contacts & dates):
TxDOT Needed?
Yes No ✓
• Coordination with Summarize need(s) & actions taken (include contacts & dates):
TAMUS Needed?
Yes No ✓
- 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
- Texas Commission on General Permit It will be filed by the Construction Contractor.
Environmental Quality 150000
No Yes ✓
Brazos River
• Authority
. No ✓ Yes
•
•
STORMWATER DESIGN GUIDELINES Page 5 of 26 APPENDIX. D. TECH. DESIGN SUMMARY
Effective February 2007 As Revised February 2009
•
•
•
• SECTION IX
• APPENDIX D - TECHNICAL DESIGN SUMMARY
• S tart Part 3 — Property Characteristics (Page 3.1 )
• : ` .Nature' and Scope of Proposed, Work: << ," `
• Existing: Land proposed for development currently used, including extent of impervious cover?
• None - Vacant
• Redevelopment of one platted lot, or two or more adjoining platted Tots.
Site
• Development Building on a single platted lot of undeveloped land.
• Project Building on two or more platted adjoining lots of undeveloped land.
• (select all Building on a single lot, or adjoining Tots, where proposed plat will not form
applicable) a new street (but may include ROW dedication to existing streets).
•
• Other (explain):
• Subdivision 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.
- 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
• Nature and drainage easements or ROW.
• Size of
Proposed
• Project
Is any work planned on land that is not platted If yes, explain:
• or on land for which platting is not pending?
• No ✓ Yes
• . FEMA FIoodplains A a
• Is any part of
subject property abutting a Named Regulatory Watercourse No ✓ Yes
• (Section II, Paragraph B1) or a tributary thereof?
• Is any part of subject property in floodplain No ✓ Yes Rate Map 4804100200
area of a FEMA - regulated watercourse?
• Encroachment(s) Encroachment purpose(s): Building site(s) Road crossing(s)
• into Floodplain
areas planned? Utility crossing(s) Other (explain):
• No ✓ N/A
• 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.
•
•
•
•
•
• STORMWATER DESIGN GUIDELINES Page 6 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 3.2)
• _ ;.Hydrologic Attributes of Subject Property (or?hase)
• Has an earlier hydrologic analysis been done for larger area including subject property?
• Yes Reference the study (& date) here, and attach copy if not already in City files.
• ✓
Is the stormwater management plan for the property in substantial conformance with the
• earlier study? Yes ✓ 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
• for Project Area here. In Part 4 describe how plan for subject property will comply
• therewith.
•
•
•
• Do existing topographic features on subject property store or detain runoff? ✓ No Yes
• Describe them (include approximate size, volume, outfall, model, etc).
•
•
• Any known drainage or flooding problems in areas near subject property? 1 No Yes
• Identify:
•
• Based on location of study property in a watershed, is Type 1 Detention (flood control) needed?
• (see Table B -1 in Appendix B)
• ✓ Detention is required. Need must be evaluated. Detention not required.
• What decision has been reached? By whom?
•
• If the need for How was determination made?
Type 1 Detention
• must be evaluated:
•
•
•
• 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
•
• Part 3 — Property Characteristics Continued (Page 3.3)
t H` drolo is Attributes of Subject Pro ert orPhase continued
• Y. 9 1 p y� )( .) r, .
• Does subject property straddle a Watershed or Basin divide? ✓ No Yes If yes,
describe splits below. In Part 4 describe design concept 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? ✓ 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:
•
•
•
• Does storm runoff drain from public easements or ROW onto or across subject property?
✓ No Yes If yes, describe facilities in easement or ROW:
•
•
• Are changes in runoff characteristics subject to change in future? Explain
N/A
•
• Conveyance Pathways (Section II, Paragraph C2)
• Must runoff from study property drain across lower properties before reaching a Regulatory
• Watercourse or tributary? No ✓ Yes
411 Describe length and characteristics of each conveyance pathway(s). Include ownership of
property(ies).
•
•
•
•
•
•
•
• 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? 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).
Detention ponds were constructed with previous phases for the Meadow Creek Subdivision
•
•
•
• Nearby
• Drainage Do any of these have hydrologic or hydraulic influence on proposed stormwater
Facilities design? ✓ No Yes If yes, explain:
•
•
•
•
•
•
•
i
•
•
•
•
•
•
• 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)
111 . F Stormwater Management Concept a
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? ✓ No Yes Separate Instrument? No Yes
Per Guidelines reference above, how will Establishing Easements (Scenario 1)
runoff be discharged to neighboring Pre - development Release (Scenario 2)
• property(ies)? Combination of the two Scenarios
• Scenario 1: If easements are proposed, describe where needed, and provide status of actions
on each. (Attached Exhibit # )
No easements are needed.
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 ponds
4
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.
4
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.
•
STORMWATER DESIGN GUIDELINES Page 10 of 26 APPENDIX. D. TECH. DESIGN SUMMARY
• Effective February 2007 As Revised February 2009
•
111
•
•
• SECTION IX
• APPENDIX D — TECHNICAL DESIGN SUMMARY
•
• Part 4 — Drainage Concept and Design Parameters Continued (Page 4.2)
;�� � ' �� �, ' A` Stormwater Mana g e ment C oncep t (con
• d - )
II Within Project Area Of Multi -Phase Project
• Identify gaining Basins or Watersheds and acres shifting:
Will project result
ID in shifting runoff
• between Basins or
between What design and mitigation is used to compensate for increased runoff
• Watersheds? from gaining basin or watershed?
• ✓ 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. ✓ On phase (or site) project basis within Project Area.
I• and /or 3, and explain below.
ID 1. Shared facility (type & location of facility; design drainage area served; relationship to size of
• Project Area): (Attached Exhibit # )
II Runoff will flow through existing detention ponds designed for the Meadow Creek Subdivision.
•
•D 2. For Overall Project Area (type & location of facilities): (Attached Exhibit # C )
• In previous phases of the project.
•
•
• 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
IR project(s)?
•moo
a) v,
ID
m r Are other Best Management Practices for reducing stormwater pollutants proposed?
• a No ✓ Yes Summarize type of BMP and extent of use:
• a, Silt Fence, Construction Exit, Seeding, Grass Block Sod, Inlet Protection
N
• a) o
a z
• ° If design of any runoff - handling facilities deviate from provisions of B -CS Technical
c n ' Specifications, check type facility(ies) and explain in later questions.
Detention elements Conduit elements Channel features
• Q Swales Ditches Inlets Valley gutters Outfalls
Culvert features Bridges Other
•
•
• STORMWATER DESIGN GUIDELINES Page 11 of 26 APPENDIX. D. TECH. DESIGN SUMMARY
• Effective February 2007 As Revised February 2009
•
•
0
•
0 SECTION IX
• APPENDIX D - TECHNICAL DESIGN SUMMARY
•
II Part 4 — Drainage Concept and Design Parameters Continued (Page 4.3)
ID - T • S tor`m w ater Management Concept (continu z
Within Project Area Of Multi -Phase Project (continued)
- Will Project Area include bridge(s) or culvert(s)? ✓ No Yes Identify type and
general size and In which phase(s).
0
II
w 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):
• The existing Detention Ponds are on the south east boundary of the parent tract and will be for all
III phases of the development.
• Within Or Serving Subject Property (Phase, or Site)
• If property part of larger Project Area, is design in substantial conformance with earlier analysis
IIII and report for larger area? ✓ Yes No, then summarize the difference(s):
SI
fit
II Identify whether each of the types of drainage features listed below are included, extent of use,
II and general characteristics.
Typical shape? Surfaces?
v
IP = Steepest side slopes: Usual front slopes: Usual back slopes:
- .
m
o Flow line slopes: least Typical distance from travelway:
ID 43=
greatest (Attached Exhibit # )
II o
N Z
ID ° ' I Are longitudinal culvert ends in compliance with B -CS Standard Specifications?
•
Q Yes No, then explain:
• N At intersections or otherwise, do valley gutters cross arterial or collector streets?
ft } ✓ No Yes If yes explain:
. v v
m
N 15 Are valley gutters proposed to cross any street away from an intersection?
• a
zt rn z ✓ No Yes Explain: (number of locations ?)
. ` c
2 as
• Q
ID
ID STORMWATER DESIGN GUIDELINES Page 12 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
ID 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) . ;
• Within Or Serving Subject Property (Phase, or Site) (continued)
• Gutter line slopes: Least 0.8% Usual 1.0% Greatest 3.0%
• Are inlets recessed on arterial and collector streets? X Yes No If "no ",
• identify where and why.
4111 N/A
411 with 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.
• v
a>
• 0 Will inlet size and placement prevent exceeding allowable water spread for 10 -year
• 5 design storm throughout site (or phase)? ✓ Yes No If no, explain.
rn See Appendix
•
• f0 s Saq curves: Are inlets placed at low points? ✓ Yes No Are inlets and
w conduit sized to prevent 100 -year stormflow from ponding at greater than 24 inches?
411 (-) v ✓ Yes No Explain "no" answers.
• 3
to
• a)
2
• 2 Will 100 -yr stormflow be contained in combination of ROW and buried conduit on
• Q 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.
•
• Are any 12 -inch laterals used? ✓ No Yes Identify length(s) and where
• used.
• c•.
• N N Pipe runs between system Typical 150 Longest 241.1
w access points (feet):
• m �I Are junction boxes used at each bend? ✓ Yes No If not, explain where
• N and why.
• c o
�z
• E
• ° Are downstream soffits at or below upstream soffits? Least amount that hydraulic
ID N Yes ✓ No If not, explain where and why: grade line is below gutter line
(system- wide):
• 2.63 Feet
•
•
• STORMWATER DESIGN GUIDELINES Page 13 of 26 APPENDIX. D. TECH. DESIGN SUMMARY
• Effective February 2007 As Revised February 2009
•
•
0
0
• SECTION IX
• APPENDIX D — TECHNICAL DESIGN SUMMARY
•
• Part 4 — Drainage Concept and Design Parameters Continued (Page 4.5)
ID , ,, Stormwater Management Concept (continued) 4
• Within Or Serving Subject Property (Phase, or Site) (continued)
0 Describe watercourse(s), or system(s) receiving system discharge(s) below
411 ° ( include design discharge velocity, and angle between converging flow lines).
4111 m 1) Watercourse (or system), velocity, and angle?
V)
4111 a Storm sewer system drains into existing detention pond.
• o
o E 2) Watercourse (or system), velocity, and angle?
c
• c o
0 o
411 v c
• 0 E v 3) Watercourse (or system), velocity, and angle?
CD m
V Y
• _
c "a O
w
o
73 Q
• E a� For each outfall above, what measures are taken to prevent erosion or scour of
receiving and all facilities at juncture?
m 1)
III 2
e 2
c 2)
a)
ch
• 0 3)
• Are swale(s) situated along property lines between properties? No Yes
III Number of instances: For each instance answer the following questions.
• Surface treatments (including low -flow flumes if any):
N
m
m u)
• v, Flow line slopes (minimum and maximum):
c
111 o
• S z Outfall characteristics for each (velocity, convergent angle, & end treatment).
• 3,
• N
2
• Q Will 100 -year design storm runoff be contained within easement(s) or platted drainage
ROW in all instances? Yes No If "no" explain:
III
STORMWATER DESIGN GUIDELINES Page 14 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
• Effective February 2007 As Revised February 2009
0
i
•
i SECTION IX
i APPENDIX D — TECHNICAL DESIGN SUMMARY
i Part 4 — Drainage Concept and Design Parameters Continued (Page 4.6)
i . ! ' + St Concept " (contin u ed)
IS Within Or Serving Subject Property (Phase, or Site) (continued)
i Are roadside ditches used? ✓ No Yes If so, provide the following:
i a Is 25 -year flow contained with 6 inches of freeboard throughout ? Yes No
Y Are top of banks separated from road shoulders 2 feet or more? Yes No
i o Are all ditch sections trapezoidal and at least 1.5 feet deep? Yes No
i a For any "no" answers provide location(s) and explain:
i `°
0
i
• If conduit is beneath a swale, provide the following information (each instance).
• Instance 1 Describe general location, approximate length:
411 ch
Is 100 -year design flow contained in conduit/swale combination? Yes No
I If "no" explain:
�
i °'
0 m Space for 100 -year storm flow? ROW Easement Width
4111 z c Swale Surface type, minimum C onduit Type and size, minimum and maximum
i >1 c and maximum slopes: slopes, design storm:
i o
1111 C o Inlets Describe how conduit is loaded (from streets /storm drains, inlets by type):
c >
ID m c
t m
- 0-o Access Describe how maintenance access is provided (to swale, into conduit):
• o .,
o co
fib D
•E .w Instance 2 Describe general location, approximate length:
• m m
m
• c a Is 100 -year design flow contained in conduit/swale combination? Yes No
ID ° o If "no" explain:
i� a
• E Space for 100 -year storm flow? ROW Easement Width
ID . o - Swale Surface type, minimum Conduit Type and size, minimum and maximum
m and maximum slopes: slopes, design storm:
i C CU
Inlets Describe how conduit is loaded (from streets /storm drains, inlets by type):
• /12
m 0
i N
°'
Q Access Describe how maintenance access is provided (to swale, into conduit):
i
i
i
i STORMWATER DESIGN GUIDELINES Page 15 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
i Effective February 2007 As Revised February 2009
i
i
0
0
• SECTION IX
• APPENDIX D - TECHNICAL DESIGN SUMMARY
•
• Part 4 — Drainage Concept and Design Parameters Continued (Page 4.7)
• . , ,,,,,-..0,.,, , f Stormwater Management Concept (continued)
IS Within Or Serving Subject Property (Phase, or Site) (continued)
• If "yes" provide the following information for each instance:
• Instance 1 Describe general location, approximate length, surfacing:
• 'ca
a
• o w
1111 6 Is 100 -year design flow contained in swale? Yes No Is swale wholly
g > within drainage ROW? Yes No Explain "no" answers:
ID
m Access Describe how maintenance access is provide:
• 2 o
D Z
•
U
111 Instance 2 Describe general location, approximate length, surfacing:
a)
• .L c...
C
• E
a)
• •§ as Is 100 -year design flow contained in swale? Yes No Is swale wholly
a o within drainage ROW? Yes No Explain "no" answers:
111 tv
ID N O
• c Access Describe how maintenance access is provided:
• U
D
Q
• Instance 3, 4, etc. If swales are used in more than two instances, attach sheet
1111 providing all above information for each instance.
• "New" channels: Will any area(s) of concentrated flow be channelized (deepened,
widened, or straightened) or otherwise altered? No ✓ Yes If only slightly
• shaped, see "Swales" in this Part. If creating side banks, provide information below.
• .E Will design replicate natural channel? Yes ✓ No If "no ", for each instance
o n describe section shape & area, flow line slope (min. & max.), surfaces, and 100 -year
o w design flow, and amount of freeboard:
• co a Instance 1:
• E } V- Shaped channel with 4:1 Side slopes at 0.30 %.
N
ID
o Instance 2:
• 0.
E °
Z
TO
c
41 `° I Instance 3:
0
GI
41
• STORMWATER DESIGN GUIDELINES Page 16 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
. Effective February 2007 As Revised February 2009
III
•
• SECTION IX
APPENDIX D - TECHNICAL DESIGN SUMMARY
•
Part 4 — Drainage Concept and Design Parameters Continued (Page 4.8)
411 xk Stormwater Management Concept (continued) y
. 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
i 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.
•
• m
• Watercourses (and tributaries): Aside from fringe changes, are Regulatory
. • Watercourses proposed to be altered? ✓ No Yes Explain below.
• c 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
411 2 and data. Is full report submitted? Yes No If "no" explain:
C
E
• • N/A
v 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.
N/A
i Will 100 -year flow be contained with one foot of freeboard? ✓ Yes No If
not, identify location and explain:
4
•
• Are ROW / easements sized to contain channel and required maintenance space?
✓ Yes No If not, identify location(s) and explain:
•
• 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
is
• Part 4 — Drainage Concept and Design Parameters Continued (Page 4.9)
• u - 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: Facility 1 Facility 2
III Acres served & design volume + 10%
• 100 -yr volume: free flow & plugged
Design discharge (10 yr & 25 yr)
Ill Spillway crest at 100 -yr WSE? yes no yes no
• Berms 6 inches above plugged WSE? yes no yes no
III Explain any "no" answers:
III
III N
a)
III 1
. For each facility what is 25 -yr design Q, and design of outlet structure?
Facility 1:
1 • o
z Facility 2:
is Do outlets and spillways discharge into a public facility in easement or ROW?
III Facility 1: Yes No Facility 2: Yes No
411 a If "no" explain:
N
. 0
Q
O
III n- For each, what is velocity of 25 -yr design discharge at outlet? & at spillway?
co
• m Facility 1: & Facility 2: &
Ill ') Are energy dissipation measures used? No Yes Describe type and al
L i location:
0
C
• a)
2 For each, is spillway surface treatment other than concrete? Yes or no, and describe:
al Q 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:
III
ID Facility 2:
1111 . •
ID STORMWATER DESIGN GUIDELINES Page 18 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
• Effective February 2007 As Revised February 2009
III
SECTION IX
APPENDIX D — TECHNICAL DESIGN SUMMARY
Part 4 Drainage Concept
and Design Parameters Continued (Page 4.10)
to, rmwater`Management Concept (continued)
• Within Or Serving Subject Property (Phase, or Site) (continued)
• Do structures comply with B -CS Specifications? Yes or no, and explain if "no ":
• Facility 1; Yes
a)
• s5 Facility 2: Yes
u
-
• For additional facilities provide all same information on a separate sheet.
- Are parking areas to be used for detention? El No _I _ Yes What is
maximum depth due to required design storm?
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:
•
co
o Are culverts parallel to public roadway alignment? Yes No Explain:
• U N
N
•
to
• Q Creeks at Private Drives: Do private driveways, drives, or streets cross drainage
ways that serve Above - Project areas or are in public easements/ ROW?
a 0
z No Yes If "yes" provide information below.
• �I How many instances? Describe location and provide information below.
- > Location 1:
• U
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.
STORMWATER DESIGN GUIDELINES Page 19 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
• Effective February 2007 As Revised February 2009
L
ID
0
SECTION IX
ID APPENDIX D — TECHNICAL DESIGN SUMMARY
III
• Part 4 — Drainage Concept and Design Parameters Continued (Page 4.11)
• k X , Stormwater Management Concept (continued)
ID Within Or Serving Subject Property (Phase, or Site) (continued)
• Named Regulatory Watercourses (& Tributaries): Are culverts proposed on these
facilities? ✓ No Yes, then provide full report documenting assumptions,
IIII criteria, analysis, computer programs, and study findings that support proposed
• design(s). Is report provided? Yes No If "no ", explain:
SI
II �, Arterial or Major Collector Streets: Will culverts serve these types of roadways?
• N No Yes How many instances? For each identify the
• . i location and provide the information below.
• > a Instance 1:
- a
5,' Instance 2:
IIII o Instance 3:
• o
ID z 'CT, Yes or No for the 100 -year design flow: 1 2 3
o Headwater WSE 1 foot below lowest curb top?
.c
• a) Spread of headwater within ROW or easement?
- rn 2 Is velocity limited per conditions (Table C -11)?
• s c Explain any "no" answer(s):
o c
• > O
a, U
• '6 O
o Minor Collector or Local Streets: Will culverts serve these types of streets?
IIIII . co No Yes How many instances? for each identify the
• D v location and provide the information below:
a a)
• CU ° Instance 1:
• w c Instance 2: ca
• o Instance 3:
0
• For each instance enter value, or "yes" / "no" for: 1 2 3
U 0
a, c Design yr. headwater WSE 1 ft. below curb top?
ID < . � 100 -yr. max. depth at street crown 2 feet or less?
41111 E Product of velocity (fps) & depth at crown (ft) _ ?
• o Is velocity limited per conditions (Table C -11)?
• Limit of down stream analysis (feet)?
• Explain any "no" answers:
ID
III
III
•
ID STORMWATER DESIGN GUIDELINES Page 20 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
• Effective February 2007 As Revised February 2009
•
SI
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? Yes No If not,
• identify location(s) and intersect angle(s), and justify the design(s):
•
• Does drainage way alignment change within or near limits of culvert and surfaced
approaches thereto? No 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 location(s) and provide justification:
Are flumes or conduit to discharge into or near surfaced approaches to culvert ends?
- No Yes If "yes" identify location(s), describe outfall design treatment(s):
•
0
•
Is scour /erosion protection provided to ensure long term stability of culvert structural
components, and surfacing at culvert ends? Yes No If "no" Identify
• locations and provide justification(s):
•
• Will 100 -yr flow and spread of backwater be fully contained in street ROW, and /or
drainage easements/ ROW? Yes No if not, why not?
• Do appreciable hydraulic effects of any culvert extend downstream or upstream to
neighboring land(s) not encompassed in subject property? No Yes If
"yes" describe location(s) and mitigation measures:
•
•
•
- Are all culvert designs and materials in compliance with B -CS Tech. Specifications?
Yes No If not, explain in Special Design Section of this Part.
•
STORMWATER DESIGN GUIDELINES Page 21 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
Effective February 2007 As Revised February 2009
•
•
•
•
• SECTION I
• APPENDIX D — TECHNICAL DESIGN SUMMARY
•
• Part 4 — Drainage Concept and Design Parameters Continued (Page 4.13)
• Stormwater Mana Concept (continued)
• Within Or Serving Subject Property (Phase, or Site) (continued)
• Is a bridge included in plans for subject property project? ✓ No Yes
If "yes" provide the following information.
• Name(s) and functional classification of the roadway(s)?
•
• What drainage way(s) is to be crossed?
• a)
CD
• m`
•
• 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:
•
•
• Is a Stormwater Provide a general description of planned techniques:
Y Pollution Prevention Construction Exits, Sediment Pond, Sit Fence, Revegetation
• Plan (SW3P)
•
0 established for
project construction?
• No ✓ Yes
•
• Special Designs — Non - Traditional Methods
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?
• ✓ No Yes If "yes" list general type and location below.
•
•
•
•
Provide full report about the proposed special design(s) including rationale for use and
• expected benefits. Report must substantiate that stormwater management objectives will not
• be compromised, and that maintenance cost will not exceed those of traditional design
solution(s). Is report provided? Yes No If "no" explain:
•
•
•
•
•
• STORMWATER DESIGN GUIDELINES Page 22 of 26 APPENDIX. D TECH. DESIGN SUMMARY
l • 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) fi
• Within Or Serving Subject Property (Phase, or Site) (continued)
• Special Designs — Deviation From B -CS Technical Specifications
• If any design(s) or material(s) of traditional runoff- handling facilities deviate from provisions of
B -CS Technical Specifications, check type facility(ies) and explain by specific detail element.
• Detention elements Drain system elements Channel features
• Culvert features Swales Ditches Inlets Outfalls
• Valley gutters Bridges (explain in bridge report)
In table below briefly identify specific element, justification for deviation(s).
• Specific Detail Element Justification for Deviation (attach additional sheets if needed)
• 1)
•
• 2 )
•
• 3 )
•
• 4 )
• 5)
•
• Have elements been coordinated with the City Engineer or her /his designee? For each item
• above provide "yes" or "no ", action date, and staff name:
• 1)
2)
• 3 )
• 4)
• 5)
• e' Design Parameters
• Hydrology
• Is a map(s) showing all Design Drainage Areas provided? ✓ Yes No
• Briefly summarize the range of applications made of the Rational Formula:
• Storm Sewer Design
•
•
• What is the size and location of largest Design Drainage Area to which the Rational Formula
• has been applied? 1 acres Location (or identifier): DA 5 & 8
•
•
• STORMWATER DESIGN GUIDELINES Page 23 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 4.15)
• „„' k _ D esign Parameters ( continued) ,
• Hydrology (continued)
• In making determinations for time of concentration, was segment analysis used?
No ✓ Yes In approximately what percent of Design Drainage Areas? 40 %
• As to intensity- duration - frequency and rain depth criteria for determining 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 N/A N/A
• Storm drain system for local streets 10 & 100 10
• Open channels 10 & 100 10
Swale /buried conduit combination in lieu of channel N/A -
4111 Swales - -
• Roadside ditches and culverts serving them 10 & 100 10
• Detention facilities: spillway crest and its outfall 2, 10, 25, 50, 100 100
• Detention facilities: outlet and conveyance structure(s) 2, 10, 25, 50, 100 100
• Detention facilities: volume when outlet plugged 100 100
• C ulverts serving private drives or streets - -
• Culverts serving public roadways 10& 100 10
• Bridges: provide in bridge report. - _
III Hydraulics
• What is the range of design flow velocities as outlined below?
• Design flow velocities; Gutters Conduit Culverts Swales Channels
• Highest (feet per second) 3.47 9.13 n/a n/a n/a
• Lowest (feet per second) 1.21 4.26 n/a n/a n/a
• Streets and Storm Drain Systems Provide the summary information outlined below:
• Roughness coefficients used: For street gutters: 0.018
• For conduit type(s) RCP HDPE Coefficients: 0.012 0.012
•
•
•
• STORMWATER DESIGN GUIDELINES Page 24 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 4.16)
• . _
'Desig 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? ✓ Yes No
• Are elevation drops provided at inlets, manholes, and junction boxes? ✓ Yes No
• Explain any "no" answers:
•
• Are hydraulic grade lines calculated and shown for design storm? ✓ Yes _ No
• For 100 -year flow conditions? ✓ Yes No Explain any "no" answers:
•
• What tailwater conditions were assumed at outfall point(s) of the storm drain system? Identify
• each location and explain:
•
•
Open Channels If a HEC analysis is utilized, does it follow Sec VI.F.5.a? Yes No
• Outside of straight sections, is flow regime within limits of sub - critical flow? 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?
•
•
•
• Entrance, friction and exit losses:
•
•
•
• 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
•
•
III
•
• SECTION IX
• APPENDIX D — TECHNICAL DESIGN SUMMARY
•
• Part 4 — Drainage Concept and Design Parameters Continued (Page 4.17)
• Z t �
t Design Parameters (continued)
• Computer Software
411 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
•
Excel spreadsheets, StormCad
•
•
•
•
•
• 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: The storm sewer system and detention facilities are designed in
• accordance with the BCS Drainage Design Guidelines.
•
•
•
•
• 1; 5.- , < A ttestation.
• 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 the 0
pr
improvements have been issued o fall under applicable general permits. :7.. ';-"Al. OF mF.{-
• , / (Affix Seal) / t; ° ).0 O f
° / }. •6 • • , so . s o• ..•••.•.om q•* r
• . � �V • J OSEPH P c ,Hrll
Licens:t Professional Engineer ° °� ° °r , m �
1111 1
/ S {j cy ' / • . , m � ••l L �•. f(j
• State of Texas PE No. 6 8 U / s . • SrF •p � <5,„'
• 2 3 z —� �� v � f r t
111
�� fM ID, 2
• STORMWATER DESIGN GUIDELINES Page 26 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
• Effective February 2007 As Revised February 2009
•
•
•
w
•
•
•
•
w
•
•
•
•
i
•
•
•
•
• EXHIBIT A
i Post Development Drainage Area Map
•
•
•
•
•
•
•
i
•
•
•
•
•
•
•
•
•
•
•
•
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