HomeMy WebLinkAboutDrainage ReportDrainage Report
for
Castlegate II Subdivision Section 102
College Station, Texas
July 2013
Owner/Developer:
3-1) Development
4490 Castlegate Drive
College Station, TX 77845
Prepared By:
Schultz Engineering, LLC
TBPE Firm No. 12327
P.O. Box 11995
College Station, TX 77842
2730 Longmire Drive, Suite A
College Station, Texas 77845
(979) 764-3900
Drainage Report — Executive Summary
Castlegate II Subdivision, Section 102
College Station, Texas
ENGINEER
SCHULTZ ENGINEERING, LLC.
P.O. Box 11995
College Station, Texas 77842
Phone: (979)764-3900
Fax: (979)764-3910
3-D Development, LLC
4490 Castlegte Drive
College Station, TX 77845
Phone: (979)690-7250
GENERAL DESCRIPTION AND LOCATION
Section 102 is the sixth phase being constructed in the Castlegate II Subdivision. It lies on the west portion of the
subdivision, and is adjacent to Section 101. It consists of 26 residential lots, and includes an extension of WS
Phillips Parkway and Muncaster Lane. Also, included are the additions of Portland Avenue and Bramber Drive. All
of Section 102 lies within the Spring Creek Drainage Basin and will drain into the previously constructed detention
pond. That pond was designed to accommodate runoff from Section 102 and all assumptions associated with its
design are still valid. No additional stormwater detention is being proposed with Section 102.
Description
• Area: 6.263 Acres
• Proposed Land Use: Single Family Residential
• #of Lots: 26lots
• Existing Land Use: Vacant
• Land Description: The terrain slopes generally towards the southeast.
Primary Drainage Facility: Spring Creek
Flood Hazard Information:
FEMA FIRM: 12-06-1841P, Dated May 18, 2012
Floodplain: None of this phase of the development lies within the floodplain.
HYDROLOGIC CHARACTERISTICS
The existing site is cleared. The elevations range from 338 to 328, sloping generally in a southwesterly direction.
The runoff will be directed to the roadways and the proposed storm sewer system will discharge into the existing
storm sewer system constructed with Sections 100 & 101 and then discharges into the existing detention facilities.
Ultimately, this runoff flows into Spring Creek Tributary A2A.
GENERAL STORMWATER PLAN
The drainage plan for this development will involve the installation of storm sewer pipes and inlets, which will
collect and convey the runoff into the existing storm sewer system and then to the existing detention pond. The
runoff that is collected by the existing detention ponds will be discharged into Spring Creek Tributary A2A.
COORDINATION & STORMWATER PERMITTING
This project has a Notice of Intent filed with the Texas Commission for Environmental Quality. No other permits
are anticipated for this project.
DRAINAGE DESIGN
General Information: Stormwater runoff from Section 102 of the subdivision will be collected by a
storm sewer system and will ultimately discharge into Spring Creek Tributary
A2A. The location of the drainage areas for evaluation of the gutter depth
check, inlet sizing, pipe evaluation and channel sizing are shown on Exhibit A &
B. Refer to Exhibit B for the locations of the inlets and storm sewer pipes.
Street Design:
Typical Streets:
Standard Cross -Section (3% cross -slope, 27' B-B Residential Roadway)
Lay down curb and gutter on residential streets
WS Phillips Parlwvay:
Super -Elevation Cross -Section (3% cross -slope, B-B Varies)
Standard Curb and gutter
Concrete Pavement
Standard recessed curb inlets (5' & 10' in length)
T, Methodology:
TR 55
T, Minimum:
10 Minutes
Design Storm Event:
10 year design storm & 100 year analysis for residential and collector streets &
storm sewer
Pipe Materials:
Class III RCP, Profile Gasket in accordance with ASTM C443, ASTM C76 and
Corrugated HDPE Storm Sewer Pipe with smooth interior
Manning's n Values:
0.013 for pipes
0.018 for Streets
Runoff Coefficients:
0.55 for developed lots
0.40 for undeveloped land upstream of property
Design Constraints:
Max. water depth in gutter: 4.5" or 0.375' for the 10 year design storm for
residential and collector streets
Min. pipe flow velocity: 2.5 fps
Max. pipe flow velocity: 15 fps
100-yr storm runoff maintained within the ROW (3" above curb)
25% reduction of cross -sectional area of pipes less than 24" in diameter
Min. 1' freeboard for the 10 year design storm.depth of flow
Design Software:
Excel Spreadsheets, Hydraflow Express Extension for AutoCAD Civil 3D 2013,
& Autodesk Civil 3D Storm Sewer Analysis.
The software was used to compute pipe capacities, flow rates and velocities,
compute hydraulic grade line elevations, headwater elevations, gutter depth &
inlet sizing.
The requirement for a 25% reduction in cross sectional area of pipes less than
24" 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 was used in the analysis and the 18" diameter pipe areas -
were reduced by 25% and a 15.6" diameter pipe was used in the analysis.
Design Results: The data presented in the Appendices indicates the gutter depth, inlet sizing,
pipe sizes and channel sizing is in accordance with the requirements of and the
City of College Station.
Detention Analysis: The stormwater runoff from Castlegate II Subdivision was previously studied
and detention ponds were designed for the entire development including this
phase.
Applicable Exhibits: Exhibit A— Drainage Area Map— Overall Layout
Exhibit B — Drainage Area Map - Storm Sewer System Layout
Appendix A — Drainage Area Summary
Appendix B 1— Depth of Flow in Gutter
Appendix B2 — Storm Sewer Inlet Summary
Appendix C — Storm Sewer Pipe Summary
Appendix D —Technical Design Summary
The storm sewer, culverts & channel drainage system for Section 102 of Castlegate II Subdivision will function
within the requirements and restrictions of the BCS Design Guidelines.
CERTIFICATION
I, Joseph P. Schultz, Licensed Professional Engineer No. 65889, State of Texas, certify that this report for the
drainage design for Castlegate H, Section 102, was prepared by me in accordance with the requirements 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 proposed drainage improvements have been
issued.
J SEPH P. SCHULIz
........ .............
65889
F-123z
5GHWZ, ENGINEERING; W.
�V"p I -
Jose V
P. Sc ultz, Y.E.
EXHIBIT A
DRAINAGE AREA MAP
STORM SEWER SYSTEM LAYOUT
.S'�chultz
Engineering,
2730 ,
Lon mire Suite A
Longmire,
College Station, Texas 77845
979.764.3900 TBPE NO. 12327
SURVEYED DESIGNED DRAWN APPROVED JOB NO. DATE
JPS RCF JPS 13-257 JULY 2013
IRAINAGE
OVERALL
LAYOUT
SCALE
VERTICAL
HORIZONTAL N/A
PLOTTING SCALE: 1:1
FILE NAME: 13-257
EXHIBIT
EXHIBIT B
DRAINAGE AREA MAP
GUTTER DEPTH LOCATION
SchUltz Engineering
Longmire,
2730 Lon mire, Suite A
College Station, Texas 77845
979.764.3900 TBPE NO. 12327
SURVEYED
DESIGNED
DRAWN
APPROVED
JOB NO.
DATE
-
JP-S
RCF
JPS
13-257
JULY 2013
CASTLEGATE JI
SECTION f 01
COLLEGE STATION, TEXAS
SCALE
VERTICAL
HORIZONTAL N/A
PLOTTING SCALE: 1:1
FILE NAME: i R-PS7
APPENDIX A
DRAINAGE AREA SUMMARY
APPENDIX A
Castlegate II Section 102
Drainage Area Summary
Area #
Area, A
(acres)
C
tc
(min)
10 year storm
100 year storm
110
(inlhr)
Q10
(cfs)
1100
(inlhr)
Q100
(cfs)
350
1.07
0.550
10.0
8.635
5.08
11.639
6.85
351
1.23
0.550
10.0
8.635
5.84
11.639
7.87
362
0.79
0.550
10.0
8.635
3.75
11.639
5.06
353
0.59
0.550
10.0
8.635
2.80
11.639
3.78
354
0.03
0.550
10.0
6.635K141.639
0.19
355
0.04
0.550
10.0
8.6351.639
0.26
356
0.03
0.550
10.0
8.6351.639
0.19
357
0.02
0.550
10.0
8.6351.639
0.13
359
0.55
0.550
10.0
8.635
2.61
11.639
3.52
360
0.43
0.550
10.0
8.635
2.04
11.639
2.75
361
0.47
0.550
10.0
8.635
2.23
11.639
3.01
362
0.27
0.550
10.0
8.635
1.28
11.639
1.73
363
0.27
0.550
10.0
8.635
1.28
1 11.639
1.73
The Rational Method:
Q = CIA
Q = Flow (cfs)
A = Area (acres)
C = Runoff Coeff.
I = Rainfall Intensity (in/hr)
I = b / (tc+d)e
tc = Time of concentration (min)
Brazos County:
2 year stonn 10 year stone
b=65 b=80
d= 8 d= 8.5
e = 0.806 e = 0.763
t, = L/(V*60)
L = Length (ft
V = Velocity (ft/sec)
25 year storm
b= 89
d= 8.5
e = 0.754
50 year storm 100 year storm
b=98. b=96
d= 8.5 d= 8.0
e=0.745 e=0.730
APPENDIX III
DEPTH OF FLOW IN GUTTER
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APPENDIX B2
STORM SEWER INLET SUMMARY
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APPENDIX B2
Castlegate II Section 102
Storm Sewer Inlets on Grade - Design Analysis
Inlet Length Street
Q10
L10,ft.
Bypass
Q100
L100,ft.
Bypass
No. ft. Slope
cfs
Design
cfs
cfs
Design
cfs
S151 10 2.96%
1.28
10.98
0.02
1.73
12.63
0.10
S409 10 0.90%
4.62
14.03
0.49
6.73
16.74
1.31
S481 10 1.20%
5.08
15.99
0.87
6.85
18.40
1.67
S482 10 1.20%
5.84
17.08
1.20
7.87
19.65
2.19
Assume 10% clogging for design
Se = Sx + (a/w)* Eo
Eo= Qw/Q = 1 - [ 1 - W/T]2.67
L=Kc*Qo.47.So.a.(1 /(n*Se))0 6
W = Width of Depressed Gutter (ft) =
2
Sx=Cross flow of Road Surface
0.03
T=Total Spread of water in gutter (ft)
12.5
a=Gutter depression depth (ft)=
0.33
n=Manning's Roughness Coefficient=
0.018
Kc=
0.6
Qw=Flow in width, W
E=Efficiency of inlet or percentage of interception
S=Longitudinal Slope
Li=Curb opening length
Se = Sx + (a/w)* Eo 0.091412
Eo= Qw/Q = 1 - [ 1 - W/T]2'67 0.372194
APPENDIX Cl
STORM SEWER PIPE SUMMARY
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APPENDIX D
TECHNICAL. DESIGN SUMMARY
SECTION IX
APPENDIX D - TECHNICAL DESIGN SUMMARY
The Cities of Bryan and College Station both require storm drainage design to follow these
Unified Stormwater Design Guidelines. Paragraph C2 of Section III (Administration) requires
submittal of a drainage report in support of the drainage plan (stormwater management plan)
proposed in connection with land development projects, both site projects and. subdivisions.
That report may be submitted as a traditional prose report, complete with applicable maps,
graphs, tables and drawings, or it may take the form of a "Technical Design Summary". The
format and content for such a summary report shall be in substantial conformance with the
description in this Appendix to those Guidelines. In either format the report must answer the
questions (affirmative or negative) and provide, at minimum, the information prescribed in the
"Technical Design Summary" in this Appendix.
The Stormwater Management Technical Design Summary Report shall include several parts
as listed below. The information called for in each part must be provided as applicable. In
addition to the requirements for the Executive Summary, this Appendix includes several
pages detailing the requirements for a Technical Design Summary Report as forms to be
completed. These are provided so that they may be copied and completed or scanned and
digitized. In addition, electronic versions of the report forms may be obtained from the City.
Requirements for the means (medium) of submittal are the same as for a conventional report
as detailed in Section III of these Guidelines.
Note: Part 1 — Executive Summary must accompany any drainage report
required to be provided in connection with any land development project,
regardless of the format chosen for said report.
Note: Parts 2 through 6 are to be provided via the forms provided in this
Appendix. Brief statements should be included in the forms as requested,
but additional information should be attached as necessary.
Part 1 — Executive Summary Report
Part 2 — Project Administration
Part 3 — Project Characteristics
Part 4 — Drainage Concept and Design Parameters
Part 5 — Plans and Specifications
Part 6 — Conclusions and Attestation
STORMWATER MANAGEMENT TECHNICAL DESIGN SUMMARY REPORT
Part 1 — Executive Summary
This is to be a brief prose report that must address each of the seven areas listed below.
Ideally it will include one or more paragraphs about each item.
1. Name, address, and contact information of the engineer submitting the report, and
of the land owner and developer (or applicant if not the owner or developer). The
date of submittal should also be included.
2. Identification of the size and general nature of the proposed project, including any
proposed project phases. This paragraph should also include reference to
STORMWATER DESIGN GUIDELINES Page 1 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
Effective February 2007 As Revised August 2012
SECTION IX
APPENDIX D - TECHNICAL DESIGN SUMMARY
applications that are in process with either City: plat(s), site plans, zoning requests,
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 August 2012
SECTION IX
APPENDIX D — TECHNICAL DESIGN SUMMARY
Part 2 — Project Administration
Start (Page 2.1)
Engineering and Design ProfessionalsInformation .
Engineering Firm Name and Address:
Jurisdiction
Schultz Engineering, LLC
City: Bryan
P.O. Box 11995
College Station, Tx 77842
✓ College Station
Date of Submittal:
November 2012
Lead Engineer's Name and Contact Info.(phone, e-mail, fax):
Other:
Joseph P. Schultz, PE email. joeschultz84@verizon.net
Phone:764-3900 fax.764-3910
Supporting Engineering / Consulting Firm(s):
Other contacts:
n/a
Developer/ Owner / Applicant Information '
Developer / Applicant Name and Address:
Phone and e-mail:
3-D Development, LLC
979-690-7250
4490 Castlegate Dr
College Station, Tx 77845
Property Owner(s) if not Developer / Applicant (& address):
Phone and e-mail:
Project identification
Development Name: Castlegate77Subdivision, Section 102
Is subject property a site project, a single-phase subdivision, or part of a multi -phase subdivision?
Multi -Phase Subdivision If multi -phase, subject property is phase 6 of 16
Legal description of subject property (phase) or Project Area:
(see Section II, Paragraph B-3a)
Robert Stevenson League, A-54, Tract 25
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.
Housing construction is beginning in the previous sections (Sections 200-202 & 100). Road and utility
construction is beginning in Section 101
General Location of Project Area, or subject property (phase):
Immediately northwest of Greens Prairie Road, about 1.3 miles Southwest of the Arrington Rd -Greens
Prairie Intersection.
In City Limits?
Extraterritorial Jurisdiction (acreage):
Bryan: acres.
Bryan: College Station:
College Station: 6.263 acres.
Acreage Outside ETJ:
STORMWATER DESIGN GUIDELINES Page 3 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
Effective February 2007 As Revised Auaust 2012
SECTION IX
APPENDIX D - TECHNICAL DESIGN SUMMARY
Part 2 — Proiect Administration
Continued (page 2.2)
Project Identification (continued) "
Roadways abutting or within Project Area or
subject property:
Victoria Avenue and WS Phillips Parkway
Abutting tracts, platted land, or built
developments:
Castlegate Subdivision, Sections 101
Named Regulatory Watercourse(s) & Watershed(s):
Spring Creek
Tributary Basin(s):
Spring Creek Tributary A2A
"Plat Information
For Project or Subject Property (or Phase)
Preliminary Plat File #: 12 - 00500004 Final Plat File #: NIA Date: July 2013
Name: CASTLEGATE II (PP) Status and Vol/Pg: submitted with this project
If two plats, second name: File #:
Status: Date:
Zoning Information,For Project or Subjec4 Property (or
Zoning Type: R-1 Existing or Proposed? Existing Case Code:
Case Date Status:
Zoning Type: Existing or Proposed? Case Code:
Case Date Status:
,'Stormwater Management Planning for Projector Subject Propertylpir Phase),.: , I.
Planning Conference(s) & Date(s):
N/A
Participants:
Preliminary Report Required? NIA Submittal Date Review Date
Review Comments Addressed? Yes _ No _ In Writing? When?
Compliance With Preliminary Drainage Report. Briefly describe (or attach documentation
explaining) any deviation(s) from provisions of Preliminary Drainage Report, if any.
STORMWATER DESIGN GUIDELINES Page 4 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
Effective February 2007 As Revised Aucust 2012
SECTION IX
APPENDIX D —TECHNICAL DESIGN SUMMARY
Part 2 — Project Administration Continued (page 2.3)
Coordination For Project or Subject Property (or, Phase)
Note: For any Coordination of stormwater matters indicated below, attach documentation
describing and substantiating any agreements, understandings, contracts, or approvals.
Dept.
Contact:
Date:
Subject:
Coordination
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 ✓
Summarize need(s) & actions taken (include contacts & dates):
Coordination with
TxDOT Needed?
Yes No ✓
Summarize need(s) & actions taken (include contacts & dates):
Coordination with
TAMUS Needed?
Yes _ No ✓
'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 ins aces below.
Entity
Permitted ' r
Status of Actions (include dates)
Approved .
Army Crops of
Permitter)
Permit approved.
Engineers
Engineers
No Yes ✓
US Environmental
Protection Agency
No ✓ Yes _
Texas Commission on
Environmental Quality
No Yes ✓
Brazos River
Authority
No ✓ Yes
STORMWATER DESIGN GUIDELINES Page 5 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
Effective February 2007 As Revised August 2012
SECTION IX
APPENDIX D — TECHNICAL DESIGN SUMMARY
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?
Proposed development is residential subdivision. High density. Impervious cover = 65%
Site
Redevelopment of one platted lot, or two or more adjoining platted lots.
Development
Building on a single platted lot of undeveloped land.
Project
Building on two or more platted adjoining lots of undeveloped land.
(select all
applicable)
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
Construction of streets and utilities to serve one or more lap tted lots.
Development
✓ Construction of streets and utilities to serve one or more proposed lots on
Project
lands represented by pending plats.
Site oroiects: 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
26lots. Approximately 1330' ofStreets.
Proposed
Project
1.108 ac. - ROW
Is any work planned on land that is not platted
If yes, explain:
or on land for which platting is not pending?
✓ No Yes
F EMA
Floodplams
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
area of a FEMA-regulated watercourse?
—
chment( into Fls)
into Floodplain
Encroachment purpose(s): Building site(s) Road crossing(s)
areas planned?
Utility crossing(s) Other (explain):
No ✓
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 August 2012
SECTION IX
APPENDIX D - TECHNICAL DESIGN SUMMARY
Part 3 — Property Characteristics
Continued (Page 3.2)
Hydrologic Attributes of Subject Property (or Phase)
Has an earlier hydrologic analysis been done for larger area including subject property?
Yes
Reference the study (& date) here, and attach copy if not already in City files.
V/
Detention & Drainage System Report for
Castlegate II Subdivision, Section 200
April, 2011
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? J No Yes
Identify:
Based on location of study property in a watershed, is Type 7 Detention (flood control) needed?
(see Table B-1 in Appendix B) Already Provided in previous phase
✓ 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 7 Detention
must be evaluated:
STORMWATER DESIGN GUIDELINES Page 7 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
Effective February 2007 As Revised August 2012
SECTION IX
APPENDIX D - TECHNICAL DESIGN SUMMARY
Part 3 — Property Characteristics
Continued (Page 3.3)
HydrologicAttributes of Subject Property
(or Phase) (continued)'
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
Conveyance Pathways (Section II, Paragraph C2)
Must runoff from study property drain across lower properties before reaching a Regulatory
Watercourse or tributary? ✓ No Yes
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 August 2012
SECTION IX
APPENDIX D - TECHNICAL DESIGN SUMMARY
Part 3 — Property Characteristics
Continued (Page 3.4)
Hydrologic Attributes;of:Subject Property (or Phase):(continuedd)' ,.
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 Pond constructed with previous phase.
Nearby
Drainage
Facilities
Do any of these have hydrologic or hydraulic influence on proposed stormwater
design? No ✓ Yes If yes, explain:
Proposed starve drains will ran directly into detention pond The Proposed storm drain design
has taken into effect the pond filling from a 100 yr storm.
STORMWATER DESIGN GUIDELINES Page 9 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
Effective February 2007 As Revised August 2012
SECTION IX
APPENDIX D — TECHNICAL DESIGN SUMMARY
Part 4 — Drainage Concept and Design Parameters
Start (Page 4.1)
Stormwater Management Concept
Discharge(s) From Upland Area(s)
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.
Discharge(s) To Lower Property(ies) (Section 11, Paragraph E1)
Does project include drainage features (existing or future) proposed to become public via
platting? ✓ No _Yes Separate Instrument? ____I(_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 # )
Scenario 2: Provide general description of how release(s) will be managed to pre -development
conditions (detention, sheet flow, partially concentrated, etc.). (Attached Exhibit # )
Combination: If combination is proposed, explain how discharge will differ from pre -
development conditions at the property line for each area (or point) of release.
If Scenario 2, or Combination are to be used, has proposed design been coordinated with
owner(s) of receiving property(ies)? No Yes Explain and provide
documentation.
STORMWATER DESIGN GUIDELINES Page 10 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
Effective February 2007 As Revised August 2012
SECTION IX
APPENDIX D - TECHNICAL DESIGN SUMMARY
Part 4 — Drainage Concept and Design Parameters
Continued (Page 4.2)
Storrhwater Management Concept (continued) '
Within Project Area Of Multi -Phase Project
Identify gaining Basins or Watersheds and acres shifting:
Will project result
in shifting runoff
between Basins or
What design and mitigation is used to compensate for increased runoff
between
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.
and/or 3, and explain below.
1. Shared facility (type & location of facility; design drainage area served; relationship to size of
Project Area): (Attached Exhibit # )
2. For Overall Proiect Area (type & location of facilities): (Attached Exhibit # )
3. By phase (or site) project: Describe planned mitigation measures for phases (or sites) in
subsequent questions of this Part.
Are aquatic echosystems proposed? No Yes In which phase(s) or
project(s)?
a
Are other Best Management Practices for reducing stormwater pollutants proposed?
a
No Yes Summarize type of BMP and extent of use:
c
I
—
rn
.N
0 0
z
If design of any runoff -handling facilities deviate from provisions of B-CS Technical
a ✓
Specifications, check type facility(ies) and explain in later questions.
0)
ro
Detention elements Conduit elements Channel features
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 August 2012
SECTION IX
APPENDIX D — TECHNICAL DESIGN SUMMARY
Part 4 — Drainacie Concept and Design Parameters
Continued (Page 4.3)
Stormwateir Management Conce�t.(continued)
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).
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 detention pond constructed with the previous phase will serve this phase. Runoff will enter the
pond through the underground storm drains.
Within Or Serving Subject Property (Phase, or Site)
If property part of larger Project Area, is design in substantial conformance with earlier analysis
and report for larger area? ✓ Yes No, then summarize the difference(s):
Identify whether each of the types of drainage features listed below are included, extent of use,
and general characteristics.
Typical shape?
Surfaces?
jSteepest
side slopes:
Usual front slopes:
Usual back slopes:
N }
Flow line slopes: least
Typical distance from travelway:
typical greatest
(Attached Exhibit # )
o
z
a
Ca
° ✓
Are longitudinal culvert ends in compliance with B-CS Standard Specifications?
E
Yes No, then explain:
N
At intersections or otherwise, do valley gutters cross arterial or collector streets?
✓ No _ Yes If yes explain:
U -C'.
✓I
Are valley gutters proposed to cross any street away from an intersection?
:3
✓ No Yes Explain: (number of locations?)
Oz°
_
N C
N cp
Q
STORMWATER DESIGN GUIDELINES Page 12 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
Effective February 2007 As Revised August 2012
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 0.60 Usual 0.80 Greatest Z53
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 f ooding of intersections (arterial
with arterial or collector)? ✓ Yes No If no, explain where and why not.
r
a:
Will inlet size and placement prevent exceeding allowable water spread for 10-year
W
design storm throughout site (or phase)? ✓ Yes No If no, explain.
m
6 3
Sao 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?
s c
✓ Yes No Explain "no" answers.
N
N
N
w
Vl
T
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.
Are any 12-inch laterals used? ✓ No Yes Identify length(s) and where
used.
C1•
yw
Pipe runs between system
Typical 133' Longest 276'
}
access points (feet):
dAre
junction boxes used at each bend? ✓ Yes _ No If not, explain where
N
and why.
c C
�z
E
N
Are downstream soffits at or below upstream soffits?
Least amount that hydraulic
w
Yes ✓ No If not, explain where and why:
grade line is below gutter line
(system -wide):
Z35'
STORMWATER DESIGN GUIDELINES Page 13 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
Effective February 2007 As Revised August 2012
SECTION IX
APPENDIX D - TECHNICAL DESIGN SUMMARY
Part 4 — Drainage Concept and Design Parameters
Continued (Page 4.5)
Sformwater Management
Concept (continued)'
Within Or Serving Subject Property (Phase, or Site) (continued)
Describe watercourse(s), or system(s) receiving system discharge(s) below
(include design discharge velocity, and angle between converging flow lines).
U
m
1) Watercourse (or system), velocity, and angle?
z
Pipe 409 Outfall. Velocity 3.98 fps.
P
0
0 E
2) Watercourse (or system), velocity, and angle?
Pipe 149 Outfall. Velocity 5.26 fps.
d
U S
a�E E
=
3) Watercourse (or system), velocity, and angle?
N N
A
0 (D
O
O
E m
For each outfall above, what measures are taken to prevent erosion or scour of
o r
receiving and all facilities atjuncture?
1) Outfall from this development will occur into downstream pipes from prev. phases
C
0
2) Outfall fiane this development will occur into downstream pipes from prev. phases
N
0
3)
Are swale(s) situated along property lines between properties? _ No Yes
Number of instances: For each instance answer the following questions.
Surface treatments (including low flow flumes if any):
fA
N
�
N
w }
c
Flow line slopes (minimum and maximum):
-`o
0
z
Outfall characteristics for each (velocity, convergent angle, & end treatment).
N
3�
y
Will 100-year design storm runoff be contained within easements) or platted drainage
ROW in all instances? Yes No If "no" explain:
STORMWATER DESIGN GUIDELINES Page 14 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
Effective February 2007 As Revised August 2012
SECTION IX
APPENDIX D - TECHNICAL DESIGN SUMMARY
Part 4 — Drainage Concept and Design Parameters
Continued (Page 4.6)
Stormwater Management Concept (continued);;
Within Or Serving Subject Property (Phase, or Site) (continued)
Are roadside ditches used? ✓ No Yes If so, provide the following:
r
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
— —
Are all ditch sections trapezoidal and at least 1.5 feet deep? Yes No
o
—
For any "no" answers provide location(s) and explain:
CU
m
0
K
If conduit is beneath a swale, provide the following information (each instance).
Instance 1 Describe general location, approximate length:
w
Is 100-year design flow contained in conduit/swale combination? —Yes —No
y
If "no" explain:
a�
U
O m
Space for 100-year storm flow? ROW Easement Width
Z c
Swale Surface type, minimum
Conduit Type and size, minimum and maximum
and maximum slopes:
slopes, design storm:
0
r`' a
Inlets Describe how conduit is loaded (from streets/storm drains, inlets by type):
C a
C C
L ca
U RC
0 o
Access Describe how maintenance access is provided (to swale, into conduit):
o m
o
a� �
.�
Instance 2 Describe general location, approximate length:
E
v,
c v
Is 100-year design flow contained in conduit/swale combination? —Yes —No
co o
if "no" explain:
a a
c
rSpace
for 100-year storm flow? ROW _ Easement Width
U
Swale Surface type, minimum
Conduit Type and size, minimum and maximum
and maximum slopes:
slopes, design storm:
c m
N
Inlets Describe how conduit is loaded (from streets/storm drains, inlets by type):
d
� c
3 °
E
Access Describe how maintenance access is provided (to swale, into conduit):
STORMWATER DESIGN GUIDELINES Page 15 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
Effective February 2007 As Revised August 2012
SECTION IX
APPENDIX D — TECHNICAL DESIGN SUMMARY
Part 4 — Drainage Concept and Design Parameters
Continued (Page 4.7)
Stormwater Management Concept (continued] r '
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:
E C"
u'i
o
vi
Is 100-year design flow contained in swale? Yes No Is swale wholly
C}
_ _
within drainage ROW? Yes No Explain "no" answers:
Access Describe how maintenance access is provide:
0
Z
o✓
Instance 2 Describe general location, approximate length, surfacing:
a c
d
'o E
s �
3co
Is 100-year design flow contained in Swale? _ Yes _ No Is swale wholly
Q
within drainage ROW? Yes No Explain "no" answers:
— o
3 �
of
Access Describe how maintenance access is provided:
U_
d
d
Instance 3. 4, etc. If swales are used in more than two instances, attach sheet
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.
Will design replicate natural channel? _ Yes No If "no", for each instance
o Q
describe section shape & area, flow line slope (min. & max.), surfaces, and 100-year
o 'uj
design flow, and amount of freeboard:
CL
Instance 1:
c�
E
d
o
Instance 2:
C.
O
Z
C V/
c
Instance 3:
m
L
U
STORMWATER DESIGN GUIDELINES Page 16 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
Effective February 2007 As Revised August 2012
SECTION IX
APPENDIX D — TECHNICAL DESIGN SUMMARY
Part 4 — Drainage Concept and Design Parameters
Continued (Page 4.8)
Stormwater Management Concept (continued)
Within Or Serving Subject Property (Phase, or Site) (continued)
Existing channels (small creeks): Are these used? No Yes
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.
a
c
c
Watercourses (and tributaries): Aside from fringe changes, are Regulatory
o
Watercourses proposed to be altered? No Yes Explain below.
y
c
Submit full report describing proposed changes to Regulatory Watercourses. Address
E
existing and proposed section size and shape, surfaces, alignment, flow line changes,
>
length affected, and capacity, and provide full documentation of analysis procedures
n
and data. Is full report submitted? Yes No If "no" explain:
E
c
G
UAll
Proposed Channel Work: For all proposed channel work, provide information
requested in next three boxes.
If design is to replicate natural channel, identify, location and length here, and describe
design in Special Design section of this Part of Report.
Will 100-year flow be contained with one foot of freeboard? _ Yes _ No If
not, identify location and explain:
Are ROW / easements sized to contain channel and required maintenance space?
Yes _ No If not, identify location(s) and explain:
STORMWATER DESIGN GUIDELINES Page 17 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
Effective February 2007 As Revised Auqust 2012
SECTION IX
APPENDIX D — TECHNICAL DESIGN SUMMARY
Part 4 —Drainage Concept and Design Parameters
Continued (Page 4.9)
`Stormwater Management Concept (continued)
Within Or Serving Subject Property (Phase, or Site) (continued)
How many facilities for subject property project? For each provide info. below.
For each dry -type facilitiy:
Facility 1
Facility 2
Acres served & design volume + 10%
100-yr volume: free flow & plugged
Design discharge (10 yr & 25 yr)
Spillway crest at 100-yr WSE?
yes no
yes no
Berms 6 inches above plugged WSE?
yes —no
yes —no
Explain any "no" answers:
w
For each facility what is 25-yr design Q, and design of outlet structure?
Facility 1:
0
ZI
Facility 2:
✓
Do outlets and spillways discharge into a public facility in easement or ROW?
Facility 1: —Yes —No Facility 2: —Yes —No
If "no" explain:
0
O
a
0
w
For each, what is velocity of 25-yr design discharge at outlet? & at s illwa ?
Facility 1: & Facility 2: &
Are energy dissipation measures used? No _ Yes Describe type and
ca
u-
location:
c
0
c
N
O
For each, is spillway surface treatment other than concrete? Yes or no, and describe:
Facility 1:
Facility 2:
For each, what measures are taken to prevent erosion or scour at receiving facility?
Facility 1:
Facility 2:
If berms are used give heights, slopes and surface treatments of sides.
Facility 1:
Facility 2:
STORMWATER DESIGN GUIDELINES Page 18 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
Effective February 2007 As Revised August 2012
SECTION IX
APPENDIX D — TECHNICAL DESIGN SUMMARY
Pan`. 4 — Drainage Concept and Design Parameters Continued (Page 4.10)
Stormwater Management Concept (continued)
Within Or Serving Subject Property (Phase, or Site) (continued)
Do structures comply with B-CS Specifications? Yes or no, and explain if "no":
Facility 1;
LL
Facility 2:
C
c .J
0
0
G U
-
o
For additional facilities provide all same information on a separate sheet.
Are parking areas to be used for detention? No Yes What is
maximum depth due to required design storm?
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:
C1.
0
LS1
C
oAre
culverts parallel to public roadway alignment? Yes — No Explain:
V �
N }
ca
o I
Creeks at Private Drives: Do private driveways, drives, or streets cross drainage
m
ways that serve Above -Project areas or are in public easements/ ROW?
Z
—No Yes If "yes" provide information below.
w
N
How many instances? Describe location and provide information below.
r
�
Location 1:
U
2
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-yearfiow?
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 August 2012
SECTION IX
APPENDIX D - TECHNICAL DESIGN SUMMARY
Part 4 — Drainage Concept and Design Parameters
Continued (Page 4.11)
Stormwater Management Coricept (continued)
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,
criteria, analysis, computer programs, and study findings that support proposed
design(s). Is report provided? Yes _ No If "no', explain:
a:
Arterial or Maior Collector Streets: Will culverts serve these types of roadways?
wNo
Yes How many instances? For each identify the
location and provide the information below.
} a
Instance 1:
N
Instance 2:
c
o
Instance 3:
c
0
o 'CU
Yes or No for the 100-year design flow:
1
2
3
z E
Headwater WSE 1 foot below lowest curb top?
IC
Spread of headwater within ROW or easement?
E
w
Is velocity limited per conditions (Table C-11)?
°c
"no"
N
Explain any answer(s):
m 16
2 cO
Tp U
3 0
o a
Minor Collector or Local Streets: Will culverts serve these types of streets?
N
No Yes How many instances? for each identify the
To —cation and provide the information below:
a(D
@
Instance 1:
N G
Instance 2:
7 �
o
Instance 3:
N
Q
For each instance enter value, or "yes" / "no" for:
1
2
=3
U 0
� y
Design yr. headwater WSE 1 ft. below curb top?
c
100-yr. max. depth at street crown 2 feet or less?
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:
STORMWATER DESIGN GUIDELINES Page 20 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
Effective February 2007 As Revised August 2012
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):
o
c
—
c
0
U
V!
>
Is scour/erosion protection provided to ensure long term stability of culvert structural
� j
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 August 2012
SECTION IX
APPENDIX D - TECHNICAL DESIGN SUMMARY
Part 4 — Drainage Concept and Design Parameters
Continued (Page 4.13)
Sformwater Management 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?
rn
rn
v
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:
w
Pollution Prevention
rock riprap, silt fence installation and inlet protection
Fa
Plan (SW3P)
a
established for
`m
project construction?
m
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
Effective February 2007 As Revised August 2012
SECTION IX
APPENDIX D - TECHNICAL DESIGN SUMMARY
Part 4 — Drainage Concept and Design Parameters
Continued (Page 4.14)
Stormwater Management Concept (continued);.
Within Or Serving Subject Property (Phase, or Site) (continued)
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 herlhis 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? ✓ Yes No
Briefly summarize the range of applications made of the Rational Formula:
Pipe Design, Inlet Design and Gutter Depth Check
What is the size and location of largest Design Drainage Area to which the Rational Formula
has been applied? .96 acres Location (or identifier): 351
STORMWATER DESIGN GUIDELINES Page 23 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
Effective February 2007 As Revised August 2012
SECTION IX
APPENDIX D — TECHNICAL DESIGN SUMMARY
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 ✓ Yes In approximately what percent of Design Drainage Areas? 100 %
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
100
Open channels
N/A
N/A
Swale/buried conduit combination in lieu of channel
NIA
NIA
Swales
N/A
100
Roadside ditches and culverts serving them
N/A
100
Detention facilities: spillway crest and its outfall
N/A
N/A
Detention facilities: outlet and conveyance structures)
N/A
N/A
Detention facilities: volume when outlet plugged
NIA
N/A
Culverts serving private drives or streets
N/A
N/A
Culverts serving public roadways
N/A
N/A
Bridges: provide in bridge report.
NIA
NIA
Hydraulics
What is the range of design flow velocities as outlined below?
Design flow velocities;
Gutters
Conduit
Culverts
Swales
Channels
Highest (feet per second)
3.38
7.43
N/A
N/A
N/A
Lowest (feet per second)
1.08
2.20
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: 0.013 0.013
STORMWATER DESIGN GUIDELINES Page 24 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
Effective February 2007 As Revised August 2012
SECTION IX
APPENDIX D - TECHNICAL DESIGN SUMMARY
Part 4 — Drainage Concept and Desian Parameters
Continued (Page 4.16)
Design Parameter's (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:
Yes, the storm drain system was designed taking into account the detention pond being fill.
Open Channels If a HEC analysis is utilized, does itfollow, 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 August 2012
SECTION IX
APPENDIX D - TECHNICAL DESIGN SUMMARY
Part 4 — Drainage Concept and Design Parameters
Continued (Page 4.17)
Design Parameters (continued)
Computer Software
What computer software has been used in the analysis and assessment of stormwater
management needs and/or the development of facility designs proposed for subject property
project? List them below, being sure to identify the software name and version, the date of the
version, any applicable patches and the publisher
Excel spreadsheets, Autodesk Civil 3D Stortn Sewer Analysis and Hydroflow
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 an concluding information here:
y g The storm server systene and detention facilities are designed in
accordance with the BCS Drainage Design Guidelines.
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 the prokZTd drainage
impro ements have been • ued or f 11 under applicable general permit%-M OF
(Affix Seal) ,V
J?
— 010
�ooi eeraeeeaaeoo. eeoea.00 as
JO$E!'H..P; SCHUL
se.
LicenPro ssional Engineer as a
State of Texas PE No. `7-(T -13
STORMWATER DESIGN GUIDELINES Page 26 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
Effective February 2007 As Revised August 2012