HomeMy WebLinkAboutDrainage Report DRAINAGE REPORT
FOR
INDIAN LAKES SUBDIVISION
PHASE 21
January 2015
PREPARED FOR:
SMILING MALLARD DEVELOPMENT, LTD.
3608 EAST 29TH STREET
BRYAN, TEXAS 77802
979-846-4384
MBESI No. 10620048
p McCLURE & BROWNE ERING/SURVEYING, INC.
U O 1008 Woodcreek Dr.,Suite 103 College Station,Tx.77845ENGINE(979)693-3838 Engineer Reg.No.F-458
Survey Reg.No. 101033-00
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` Indian Lakes Subdivision, Phase 21
Stormwater Management Technical Design Summary Report
MBESI No. 10620048
PP
PART 1 —Executive Summary Report
Section 1 —Contact Information
Project Designer: McClure and Browne Engineering and Surveying, Inc.
1008 Woodcreek Drive, Suite 103
College Station, TX 77845
979-693-3838
Project Developer: Smiling Mallard Development, Ltd.
3608 East 29th Street
Bryan, Texas 77802
Section 2—General Information and Project Location
!'
This development is the 21' phase of a multi-phase subdivision. Phase 21 consists of 12 lots. The
phase is located in the Indian Lakes Village which is down Arrington Rd. approximately 2 miles from
the Arrington Rd./William D. Fitch Pkwy intersection. Phase 21 lies in the northeast portion of the
subdivision near the intersection of Mesa Verde Drive and Chaco Canyon Drive. The entire
subdivision has been analyzed in the initial drainage report submitted in September, 2000. The
development is located within the ETJ of College Station.
The project site is in the Peach Creek watershed. According to the Flood Insurance Rate Maps for
Brazos County, Texas and incorporated area, Map Number 48041C0350E effective May 16, 2012; no
portion of this property is located in a 100-year flood hazard area.
Culvert pipe and ditch sizing calculations are shown with this submittal.
The culverts and ditches peak runoffs were found using the Rational Method. A runoff coefficient (c) of
0.50 was used for residential areas since all the lots have an area greater than 1 acre. The ditches along
the proposed roadways are uniform throughout the project. The ditch profiles along all proposed
inroadways were determined using the largest ditch drainage area found for Phase 21. The culverts and
ib ditches were analyzed using an Excel Spreadsheet which utilizes Manning's Equation for the analysis.
Section 3 —Reference
Exhibit A Technical Design Summary
Exhibit B Drainage Area Map
Exhibit C-1 Rational Method Calculations
Exhibit C-2 Culvert Sizing Calculations
Exhibit C-3 Ditch Capacity Calculations
imp
Drainage Report
WOO Tnrlian T akec Phace 71
i
i
SECTION IX
APPENDIX D - TECHNICAL DESIGN SUMMARY
The Cities of Bryan and College Station both require storm drainage design to follow these
Unified Stormwater Design Guidelines. Paragraph C2 of Section III (Administration) requires
submittal of a drainage report in support of the drainage plan (stormwater management plan)
proposed in connection with land development projects, both site projects and subdivisions.
That report may be submitted as a traditional prose report, complete with applicable maps,
graphs, tables and drawings, or it may take the form of a "Technical Design Summary". The
format and content for such a summary report shall be in substantial conformance with the
description in this Appendix to those Guidelines. In either format the report must answer the
questions (affirmative or negative) and provide, at minimum, the information prescribed in the
"Technical Design Summary" in this Appendix.
The Stormwater Management Technical Design Summary Report shall include several parts
as listed below. The information called for in each part must be provided as applicable. In
addition to the requirements for the Executive Summary, this Appendix includes several
pages detailing the requirements for a Technical Design Summary Report as forms to be
completed. These are provided so that they may be copied and completed or scanned and
digitized. In addition, electronic versions of the report forms may be obtained from the City.
Requirements for the means (medium) of submittal are the same as for a conventional report
as detailed in Section III of these Guidelines.
Note: Part 1 — Executive Summary must accompany any drainage report
required to be provided in connection with any land development project,
regardless of the format chosen for said report.
Note: Parts 2 through 6 are to be provided via the forms provided in this
Appendix. Brief statements should be included in the forms as requested,
but additional information should be attached as necessary.
Part 1 — Executive Summary Report
Part 2— Project Administration
Part 3— Project Characteristics
Part 4— Drainage Concept and Design Parameters
Part 5— Plans and Specifications
Part 6—Conclusions and Attestation
STORMWATER MANAGEMENT TECHNICAL DESIGN SUMMARY REPORT
Part 1 — Executive Summary
This is to be a brief prose report that must address each of the seven areas listed below.
Ideally it will include one or more paragraphs about each item.
1. Name, address, and contact information of the engineer submitting the report, and
of the land owner and developer (or applicant if not the owner or developer). The
date of submittal should also be included.
2. Identification of the size and general nature of the proposed project, including any
proposed project phases. This paragraph should also include reference to
applications that are in process with either City: plat(s), site plans, zoning requests,
STORMWATER DESIGN GUIDELINES Page 1 of 26 APPENDIX. D:TECH. DESIGN SUMMARY
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SECTION IX
APPENDIX D - TECHNICAL DESIGN SUMMARY
or clearing/grading permits, as well as reference to any application numbers or mm
codes assigned by the City to such request.
3. The location of the project should be described. This should identify the Named
PI
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 0,1
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. lam
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 OP
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
mm
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: OP
"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."
111.
eat
OP
wax
STORMWATER DESIGN GUIDELINES Page 2 of 26 APPENDIX. D:TECH. DESIGN SUMMARY
Effective February 2007 As Revised February 2009
SECTION IX
APPENDIX D - TECHNICAL DESIGN SUMMARY
Part 2— Project Administration Start (Page 2.1)
Engineering and Design Professionals Information
,,„ Engineering Firm Name and Address: Jurisdiction
City: Bryan
Il1r McClure & Browne Engineering/Surveying, Inc.
1008 Woodcreek Drive, Suite 103 X College Station
College Station, Texas 77845 Date of Submittal:
, [
(979) 693-3838
Lead Engineer's Name and Contact Info.(phone, e-mail,fax): Other:
Jeffery L. Robertson, P.E.
ISupporting Engineering/Consulting Firm(s): Other contacts:
IDeveloper/Owner/Applicant Information
Developer/Applicant Name and Address: Phone and e-mail:
U
Smiling Mallard Development, Ltd. (979) 846 4384
3608 East 29th Street
Bryan, Texas 77802
I
Property Owner(s) if not Developer/ Applicant(&address): Phone and e-mail:
I Project Identification
Development Name: Indian Lakes, Phase 21
Is subject property a site project, a single-phase subdivision, or part of a multi-phase subdivision?
CMulti-phase Subdivision If multi-phase, subject property is phase 21 of
Legal description of subject property(phase)or Project Area:
(see Section II, Paragraph B-3a)
Indian Lakes, Phase 21
IIf 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.
I The project is the 21st phase of a multi phase subdivision. At this time the first phase has
been built. Phase 1 was submitted in September, 2000 and consisted of 58 lots. The most
recent phase submitted was Ph. 19.
I I
General Location of Project Area, or subject property(phase):
Project site is located near the intersection of Mesa Verde Drive and Chaco Canyon Drive
in College Station, Texas.
In City Limits? ' Extraterritorial Jurisdiction (acreage):
Bryan: acres. Bryan: College Station: 31.52
ICollege Station: acres. Acreage Outside ETJ:
I E
STORMWATER DESIGN GUIDELINES Page 3 of 26 APPENDIX. D:TECH. DESIGN SUMMARY
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SECTION IX
APPENDIX D - TECHNICAL DESIGN SUMMARY
Part 2— Project Administration Continued (page 2.2)
mm
Project Identification (continued)
Roadways abutting or within Project Area or Abutting tracts, platted land, or built ■N
subject property: developments:
Mesa Verde Drive & Chaco Canyon Drive
Indian Lakes Phase 5, Indian Lakes Phase 19, WM
& Undeveloped Land
Named Regulatory Watercourse(s)&Watershed(s): Tributary Basin(s):
The nearest tributary is Peach Creek S.
Phase 21 is located in the Peach Creek Watershed. N
Tributary 7.2 (See FEMA Map 48041C0350E) .
Plat Information For Project or Subject Property(or Phase) se,
Preliminary Plat File#: Final Plat File#: Date:
Name: Pending Approval Status and Vol/Pg: Pending Approval
If two plats, sec. • . - . FtMir
Status: • - •
-
•
Zoning Information For Project or Subject Property(or Phase)
or
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)
nning Conference(s) & Date(s): Participants:
Preliminary Report Requires Submittal Date 'eview Date
Review Comments Addressed? Yes No In Wr ' g? When?
Compliance With Preliminary Drainage R- : •rt. efly describe (or attach documentation
explaining)any deviation(s)from provisions of P' inary Drainage Report, if any. NO
N
N
rr
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a..
mik
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Effective February 2007 As Revised February 2009 •
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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.
ft* Coordina Dept. _ Contact: Date: Sub'ect:
With Other
Mb
Departments of
Jurisdiction
City(Bryan or
College Statiot
Coordination With mmarize need(s)&actions taken (include contacts &dates):
Non-jurisdiction
City Needed?
Yes No X
Coordination with Summarize need(s : actions taken (include contacts : sates):
Brazos County
awF Needed?
Yes No X
Coordination with Summarize need(s)&actions take. in de contacts &dates):
0. TxDOT Needed?
Yes No x
Coordination with Summarize ne:• s)&actions taken (include contacts &da : :
TAMUS Needed?
Yes No X
Permits For Project or Subject Property(or Phase)
As to stormwater management, are permits required for the proposed work from any of the entities
listed below? If so, summarize status of efforts toward that objective in spaces below.
0111 Permitted or
Entity Approved ? Status of Actions (include dates)
US Army Crops of
Engineers
No X Yes
US Environmental
Protection Agency
No X Yes
Texas Commission on A Stormwater Pollution Prevention Plan must be
act Environmental Quality implemented prior to the start of construction
No Yes X according to TPDES General Permit No. TXR150000.
Brazos River
Authority
No X Yes
rr.
STORMWATER DESIGN GUIDELINES Page 5 of 26 APPENDIX. D:TECH. DESIGN SUMMARY
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APPENDIX D - TECHNICAL DESIGN SUMMARY
OP
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? MP
Existing undeveloped land (Dense tree cover) . Existing impervious cover is
approximately 0 sf.
•-.evelopment of one platted lot, or two or more adjoining plat s.
Site
°•E
Development Building on a '•• e platted lot of undeveloped la •.
Project Building on two or more p a - .d'•'•' • ots of undeveloped land.
(select all
applicable) Building on a single • , • adjoining lots, , : - .ro.osed plat will not form
a new stre- .. may include ROW dedication to e•' '.• streets).
er(explain):
Subdivision X Construction of streets and utilities to serve one or more platted lots.
Development Construction of streets and utilities to serve one or more proposed lots on
Project lands represented by pending plats.
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 This phase of the subdivision includes 12 lots. The development 40
Proposed consists of approximately 1,593 LF of streets with 16' PUE on each
Project side of the streets ROW. MR
US
Is any work planned on land that is not platted , Iain:
or on land for which platting is not pending?
X No Yes
FEMA Floodplains
Is any part of subject property abutting a Named Regulatory Watercourse No X Yes •
(Section II, Paragraph B1)or a tributary thereof? —
Is any part of subject property in floodplain No Yes X Rate Map 48041C0350E
area of a FEMA-regulated watercourse?
rr
Encroachment(s) Encroac :• •urpose(s): Building site(s) Roadng(s)
into Floodplain
areas planned? Utility crossing(s) •ther(ex. ..• .
No X egg
Yes
—Trfitgodialais not shown on Rate Maps, has work been done toward amending the F
approved Floor• •: • define allowable encroachments in proposed are. •• am.
STORMWATER DESIGN GUIDELINES Page 6 of 26 APPENDIX. D:TECH. DESIGN SUMMARY
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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.
Indian Lakes Subdivision; September, 2000
X
Is the stormwater management plan for the property in substantial conformance with the
earlier study? Yes X No If not, explain how it differs.
No •'ect property is not part of multi-phase project, describe stormwater manageme
plan for : •roperty in Part 4.
If property is part • Iti-phase project, provide overview of storm - - management plan
rr for Project Area here. In =:• 4 describe how plan for sub.- • operty will comply
therewith.
o m
orm
it
Do existing topographic features on subject property store or detain runoff? X No Yes
am Describe them (include approximate size, volume, outfall, model, etc).
um
Any known drainage or flooding problems in areas near subject property? X No Yes
m. Identify:
Based on location of study property in a watershed, is Type 1 Detention (flood control)needed?
WNW (see Table B-1 in Appendix B)
,,,,„ Detention is required. X Need must be evaluated. Detention not required.
What decision has been reached? By whom?
••.
Detention study during Phase 1.
If the need for
How was determination made?
Type 1 Detention
must be evaluated: Detention was required and is provided for the entire
Indian Lakes Subdivision. Phase 21 does not require
arw
any additional detention.
0.
00.
0.
STORMWATER DESIGN GUIDELINES Page 7 of 26 APPENDIX. D:TECH. DESIGN SUMMARY
`w Effective February 2007 As Revised February 2009
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SECTION IX
APPENDIX D — TECHNICAL DESIGN SUMMARY
sr
Part 3 — Property Characteristics Continued (Page 3.3)
614
Hydrologic Attributes of Subject Property(or Phase) (continued)
Does subject property straddle a Watershed or Basin divide? x No Yes If yes,
describe splits below. In Part 4 describe design concept for handling this.
Watershed or Basin Larger acreage Lesse e
Above-Project Areas(Section II, Paragraph B3-a)
Does Project Area (project or phase) receive runoff from upland areas? No x Yes
Size(s)of area(s) in acres: 1) 7.05 2) 3) 4)
Flow Characteristics (each instance)(overland sheet, shallow concentrated, recognizable
concentrated section(s),small creek(non-regulatory), regulatory Watercourse or tributary);
Overland flow to proposed ditch lines on Phase 21 streets.
Flow determination: Outline hydrologic methods and assumptions:
The Rational Method was used for flow calculations and the post development
land was treated as large acre residential tracts.
Does storm runoff drain from public easements or ROW onto or across subject property?
x No Yes If yes, describe facilities in easement or ROW:
Are changes in runoff characteristics subject to change in future? Explain
No, upstream land is already developed.
Conveyance Pathways (Section II, Paragraph C2)
Must runoff from study property drain across lower properties before reaching a Regulatory
Watercourse or tributary? No x Yes
Describe length and characteristics of each conveyance pathway(s). Include ownership of
property(ies).
Runoff from Ph. 21 will leave the phase and be discharged into existing
tributaries of Peach Creek. The property is a future phase
of the Indian Lakes Subdivision.
M11►
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)
410y. Do drainage es,for what part of length? % Created by? plat, or
easements instrument. If instrument(s), describe their provisions.
exist for any
tom
part of
pathway(s)?
x No
' Yes
Where runoff must cross lower p .•erties, describe charac - istics of abutting lower
property(ies). (Existing watercourse '2 Easement or Co• ent aquired?)
Pathway
Areas
' Describe any built or imprs•ed drainage facilities existing nea e property(culverts,
bridges, lined channels •uried conduit, swales, detention ponds, -tc).
1
Nearby
Drainage Do any of these have hydrologic or hydraulic influence on proposed stormwater
' Facilities design? x No Yes If yes, explain:
1
1
I STORMWATER DESIGN GUIDELINES Page 9 of 26 APPENDIX. D:TECH. DESIGN SUMMARY
Effective February 2007 As Revised February 2009
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SECTION IX '"
APPENDIX D - TECHNICAL DESIGN SUMMARY
•
Part 4— Drainage Concept and Design Parameters Start (Page 4.1)
Stormwater Management Concept
0
Discharge(s) From Upland Area(s)
es
ff is to be received from upland areas, what design drainage features will be used t
accomm - it and insure it is not blocked by future development? Describe fo area,
MR
flow section, or si - se point.
aup
wll
Discharge(s) To Lower Property(ies) (Section II, Paragraph El)
Does project include drainage features (existing or future) proposed to become public via A
platting? X No Yes Separate Instrument? X No Yes
.rr
er Guidelines reference above, how will Establishing Easements (Scenario 1)
ru ff be discharged to neighboring Pre-development Release (Scenari 2) IN
prop (ie:s)?
Combination of the two Scenari
Was
Scenario 1_ If easements are proposed, describe where needed, and provide stat of actions
on each. (Atta• ed Exhibit# )
PO
Scenario 2_ Provide general de- ription of how release(s)wil se managed to pre-development
conditions (detention, sheet flow, p: ially concentrated, et . . (Attached Exhibit#
0
w
Combination: If combination is pro..sed, explain how . harge will differ from pre-
development conditions at the pr..erty line for each area (o soint)of release.
0
If Scenario 2, o ombination are to be used, has proposed design been coor.' ated with
owner(s)of r- eiving property(ies)? No Yes Explain and pro ' e OP
documen ion.
.rr
II
STORMWATER DESIGN GUIDELINES Page 10 of 26 APPENDIX. D:TECH. DESIGN SUMMARY
Effective February 2007 As Revised February 2009 ""
SECTION IX
ikt APPENDIX D - TECHNICAL DESIGN SUMMARY
i. Part 4— Drainage Concept and Design Parameters Continued (Page 4.2)
Stormwater Management Concept (continued)
Within Project Area Of Multi-Phase Project
-• ' gaining Basins or Watersheds and acres shifting:
Will project result
in shifting runoff
between Basins or
between What design and mitigation is us-; . : pensate for increased runoff
Watersheds? from gaining basin or watersh-• .
I X No
Yes
How will runoff from Project 1. With facility(ies) involving other development projects.
Area be mitigated to pre-
2. Establishing features to serve overall Project Area.
development conditions?
I Select any or all of 1, 2, 3. X On phase(or site) project basis within Project Area.
and/or 3, and explain below.
. eared facilit (type&location of facility; design drainage area served; relationship to siz-
IProject • -- : (Attached Exhibit# )
L
2. For Overall Project Area (type &loc. of facile i-- • Attached Exhibit# )
C
3. By phase (or site)project: Describe planned mitigation measures for phases (or sites) in
subsequent questions of this Part.
• - aquatic echosystems proposed? No Yes In which phase(s)or
I
proje ?
a) N
I c r Are other Best Manag- •-nt Practices for reducing stormwate .. lutants proposed?
ET_ No Yes Su .rize type of BMP and = ent of use:
c
as
c
m o
I i 0 Z
If design of any runoff-handlin! .cilities deviate from p : isions of B-CS Technical
n X Specifications, check ty.- acility(ies)and explain in later q - ions.
I
< Detention - - ents Conduit elements Cha I features
m
Q Sw. Ditches Inlets Valley gutters •.•.IIs
IPP, Culvert features Bridges Other
6
I STORMWATER DESIGN GUIDELINES Page 11 of 26 APPENDIX. D:TECH. DESIGN SUMMARY
Effective February 2007 As Revised February 2009
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SECTION IX
APPENDIX D - TECHNICAL DESIGN SUMMARY
Part 4— Drainage Concept and Design Parameters Continued (Page 4.3)
Stormwater Management Concept(continued)
Within Prosect Area Of Multi-Phase Project(continued) Pe
Will Project Area include bridge(s)or culvert(s)? No X Yes Identify type and .a
general size and In which phase(s).
Culvert #1 - 2 24" RCP Pipes on Makawee Lane MI
Culvert #2 - 2 30" RCP Pipes on Chaco Canyon Drive
-1 'd'etei/retention serves (will serve)overall Project Area, describe how it relates t. _: -
phase or site pr.' - .h sical location, conveyance pathway(s), constru .quence): ..
Within Or Serving Subject Property(Phase, or Site)
rpreper .art of larger Project Area, is design in substantial conform.• - ' i earlier analysis
and report for . .- - -a? Yes No, then .nze the difference(s):
1111
Identify whether each of the types of drainage features listed below are included, extent of use, Nil
and general characteristics.
Typical shape? Surfaces?
c•-• V-Shape Grass
-o
cn Steepest side slopes: Usual front slopes: Usual back slopes:
>- 4:1 4:1 4:1 NO
a)
c.) x Flow line slopes: least o.65% Typical distance from travelway: 11'
0 typical Varies greatest 3.15 o (Attached Exhibit#
MPz
2 Are longitudinal culvert ends in compliance with B-CS Standard Specifications?
Yes No, then explain:
.r
0) • - -rsections or otherwise, do valley gutters cross arterial or collector stre .
. Yes If yes explain:
MP
U -
�
Are valley gutters proposed to cross . -- away from an intersection?
a
i z •No Yes Explain . ser of loca .-_2
MO
2.2 co X
IN
rr
STORMWATER DESIGN GUIDELINES Page 12 of 26 APPENDIX. D:TECH. DESIGN SUMMARY
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I
I SECTION IX
APPENDIX D - TECHNICAL DESIGN SUMMARY
Part 4— Drainage Concept and Design Parameters Continued (Page 4.4)
Stormwater Management Concept (continued)
IWithin Or Serving Subject Property(Phase, or Site) (continued)
tter line slopes: Least Usual Greatest
I Are i ets recessed on arterial and collector streets? Yes No "no",
identify here and why.
I Will inlets captu : 10-year design stormflow to prevent flooding of' tersections(arterial
with arterial or coil-. or)? Yes No If no, expl.' where and why not.
C-•
I
Will inlet size and placemen .revent exceeding allows,. e water spread for 10 year
'a-) design storm throughout site(. shase)? Y-: No If no, explain.
5
m
c 10
I `° 2 Sag curves: Are inlets placed at low poi . Yes No Are inlets and
m1.- , conduit sized to prevent 100-year storm . rom ponding at greater than 24 inches?
gYes No Explain "n."answe
I)
II
2
m Will 100-yr stormflow b- ontained in combination of ROW a . buried conduit on
whole length of all st •ets? Yes No If no, des 'be where and why.
I
Do desig for curb, gutter, and inlets comply with B-CS Technical Specific.Vons?
II es No If not, describe difference(s)and attach justification.
1 ! • - any 12-inch laterals used? No Yes Identify length(s)and wher-
use..
Pipe runs between tern Typical Longest
1 I m } access points (feet): yp g
aa)) Are junction boxes used at each •- d? Yes No If not, explain where
Nand why.
I , o
a
E x
y Are downstream soff : at or below upstream soffits? Leas _ ount that hydraulic
I
N Yes N. If not, explain where and why: grade line ' selow gutter line
(system-wide):
ar
STORMWATER DESIGN GUIDELINES Page 13 of 26 APPENDIX. D:TECH. DESIGN SUMMARY
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1 I
SECTION IX
APPENDIX D — TECHNICAL DESIGN SUMMARY
Part 4— Drainage Concept and Design Parameters Continued (Page 4.5)
Stormwater Management Concept (continued)
Within Or Serving Subject Property(Phase, or Site) (continued)
INS
N Describe watercourse(s), or system(s) receiving system discharge(s) below
(include design discharge velocity, and angle between converging flow line .
PP
1) atercourse (or system), velocity, and angle?
E
a OR
E 2) Watercourse : system), velocity, and angle?
o
E o
oU c
aa)) E3)Watercourse(or system), veloci .-. angle?
4
c -a O w
173. o
-0
n
E For each outfall abov-, what measures are taken to . event erosion or scour of
receiving and all , ilities at juncture? 011
cn
a) 1) „r,
2)
a>
3)
swale(s)situated along property lines between properties? No s
Num.-r of instances: For each instance answer the following questio . -
Surface tr-: ments (including low-flow flumes if any):
a)
a� u
u, } Flow line slopes (minimum .-. maximum):
f
a
a) O la
Z Outfall characteristics for each (velo , conver.- t angle, &end treatment).
ow
aux
Ta
Q Will 100-year desi.• storm runoff be contained within easement(s .r platted drainage
ROW in all inst. ces? Yes No If"no"explain:
STORMWATER DESIGN GUIDELINES Page 14 of 26 APPENDIX. D:TECH. DESIGN SUMMARY
Effective February 2007 As Revised February 2009
wr
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)
46.
Are roadside ditches used? No X Yes If so, provide the following:
rIs 25-year flow contained with 6 inches of freeboard throughout? X Yes No
Are top of banks separated from road shoulders 2 feet or more? X Yes No
OV 0 Are all ditch sections trapezoidal and at least 1.5 feet deep? Yes X No
a)
For any"no"answers provide location(s)and explain:
All Ditches are V-shaped and at least 2' deep
0
err �
*o conduit is beneath a swale, provide the following information (each instance).
rr Ins :nce 1 Describe general location, approximate length:
/01
>- Is 100-ye. design flow contained in conduit/swale combination? Ye No
- If "no"expla' :
a)
o a Space for 100-ye:r storm flow? ROW Easement W.:th
is Z .c Swale Surface ty•-, minimum Conduit Type and size, minim and maximum
x Ts and maximum slopes: slopes, design storm:
o
ui
TD m Inlets Describe how condui 's loaded (from streets/stor ' drains, inlets by type):
c• >-
• Ca/
OPP L
U
c
oo Access Describe how maintenance . cess is p •vided (to swale, into conduit):
w. o E
• o
.D Instance 2 Describe general location, .ppro ' ate length:
E
N m
c 7 Is 100-year design flow containe. in conduit/swale c. bination? Yes No
o ` If "no"explain:
w c 0-
E r Space for 100-year storm 'ow? ROW Easement Width
o a Swale Surface type, ' imum Conduit Type and size, mi ' um and maximum
7 m and maximum slope slopes, design storm:
L-
C m
imp Inlets Describe ow conduit is loaded (from streets/storm drains, inl by type):
a)
m c
' 3 0
Q Access rescribe how maintenance access is provided (to swale, into condu :
STORMWATER DESIGN GUIDELINES Page 15 of 26 APPENDIX. D:TECH. DESIGN SUMMARY
Effective February 2007 As Revised February 2009
SECTION IX
APPENDIX D - TECHNICAL DESIGN SUMMARY
Part 4— Drainage Concept and Design Parameters Continued (Page 4.7)
Stormwater Management Concept (continued)
Within Or Serving Subject Property(Phase, or Site) (continued)
\I'f "yes" provide the following information for each instance:
Ins : ce 1 Describe general location, approximate length, surfacing:
4.4
Uj
4-
ui Is 100-year design .w contained in swale? Yes No Is swale wholly
c within drainage ROW: Yes No Explain "no" - swers: •••
a)
Access Describe how mainte Ince access is provide.
o •ri
Z
0ocx 111,
0 Instance 2 Describe general location, app .ximate length, surfacing:
a)
•c c,-•
a
aa)
o E
L a)
.3 2 Is 100-year design flow co :tined in swale? Yes No Is swale wholly
a o within drainage ROW? Yes No Explain "no'answers:
U) O
Access Descr'.e how maintenance access is provided:
111•
Ins nce 3,4, etc. If swales are used in more than two instances, attach sheet
7oviding all above information for each instance.
-w" channels: Will any area(s)of concentrated flow be channelized (deepened OBI
wide _. or straightened)or otherwise altered? No Yes If only tly
shaped, s-- "Swales"in this Part. If creating side banks, provide inforrnati elow.
.c Will design repli : e natural channel? Yes No If"no" •r each instance •••
o a describe section sha._ &area, flow line slope (min. &max.), s --ces, and 100-year
w design flow, and amount • reeboard:
a Instance 1:
cn
m .r
>_
a)
>
Instance 2:
E a
Z
c x Instance 3:
WO
L
U
1111.
STORMWATER DESIGN GUIDELINES Page 16 of 26 APPENDIX. D:TECH. DESIGN SUMMARY
Effective February 2007 As Revised February 2009
II
r SECTION IX
APPENDIX D - TECHNICAL DESIGN SUMMARY
IPart 4— Drainage Concept and Design Parameters Continued (Page 4.8)
Stormwater Management Concept(continued)
Within Or Serving Subject Property(Phase, or Site) (continued)
xistinq channels(small creeks): Are these used? No Yes
I "yes"provide the information below.
I Wi small creeks and their floodplains remain undisturbed? Yes N. How
man disturbance instances? Identify each planned location:
IFor each loc:tion, describe length and general type of proposed impro •ment
(including floo6 slain changes):
I
For each location, des. ibe section shape &area,flow line sl.se (min. & max.),
Isurfaces, and 100-year .-sign flow.
Im
c
'C' Watercourses (and tributaries): ".ide from fri .e changes, are Regulatory
o
Watercourses proposed to be altered .o Yes Explain below.
cn
Submit full report describing proposed c' .n;-s to Regulatory Watercourses. Address
E existing and proposed section size and sh.4.e, surfaces, alignment,flow line changes,
> length affected, and capacity, and provid• f documentation of analysis procedures
a and data. Is full report submitted? ..s No If"no"explain:
E
T1)
UAll Proposed Channel Work: or all proposed chan el work, provide information
requested in next three boxe .
I If design is to replicate nat al channel, identify location a . length here, and describe
design in Special Design _ection of this Part of Report.
M1 ' Will 100-year flo be contained with one foot of freeboard? Y_ No If
not, identify loc.. ion and explain:
II
1 I Are Rei /easements sized to contain channel and required maintenance spa.e?
!I es No If not, identify location(s)and explain:
I
I STORMWATER DESIGN GUIDELINES Page 17 of 26 APPENDIX. D:TECH. DESIGN SUMMARY
Effective February 2007 As Revised February 2009
i
SECTION IX
APPENDIX D - TECHNICAL DESIGN SUMMARY
Part 4— Drainage Concept and Design Parameters Continued (Page 4.9)
OM
Stormwater Management Concept (continued)
Mt
Within Or Serving Subject Property(Phase, or Site) (continued)
\ ow many facilities for subject property project? For each provide info. belo . "�'"
Ft each dry-type facilitiy: Facility 1 Facility 2 -
Acre, served &design volume + 10%
1(10-yr olume: free flow& plugged
Design di-. harge (10 yr&25 yr) ilIF
Spillway ore.. at 100-yr WSE? yes no y s no .r
Berms 6 inche- above plugged WSE? yes no yes no
Illi
Explain any"no" swers:
iiii
a) IP
>-
.r
For each facility what is 25- design Q, and design of ou -t structure?
Facility 1: 1°r
0
z Facility 2:
X Do outlets and spillways discharge i,to a public fa'ility in easement or ROW?
MI
Facility 1: Yes No Facilit, 2: Yes No
0 If"no"explain:
co
n an
0
- For each, what is velocity of 25-yr desi; disch-rge at outlet? &at spillway? NO
a) Facility 1: & Faci' y 2: &
Are energy dissipation measures .ed? No Yes Describe type and al
u- location: iii
c
0
c S
m R
a)
D
m For each, is spillway su .ce treatment other than concrete? es or no, and describe:
Q
Facility 1: as
Facility 2: ,l,,,
For each, what r easures are taken to prevent erosion or scour at rec-'ving facility?
Facility 1: 3
Facility 2:
If berm are used give heights, slopes and surface treatments of sides.
Facili 1: 3
/Jollity 2: 1
wil
iii
STORMWATER DESIGN GUIDELINES Page 18 of 26 APPENDIX. D:TECH. DESIGN SUMMARY
Effective February 2007 As Revised February 2009 'i
■11
SECTION IX
APPENDIX D - TECHNICAL DESIGN SUMMARY
Part 4— Drainage Concept and Design Parameters Continued (Page 4.10)
Stormwater Management Concept (continued)
' Within Or Serving Subject Property(Phase, or Site) (continued)
64, :: tructures comply with B-CS Specifications? Yes or no, and explain if"no":
Facility 1;
u)
a)
IMO .5
2 '5 Facility 2:
eme C .—
o c
.0 o
. o
Oa a)
a) For additional facilitie • ovide all same information on a sepa : - sheet.
a
Are parkins . -as to be used for detention? No Yes
6 ma.'• Im depth due to required design storm?
Roadside Ditches:Will culverts serve access driveways at roadside ditches?
t No x 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
I
Designs &materials comply with B-CS Technical Specifications? Yes No
Explain any"no" answers:
u)
c
o Are culverts parallel to public roadway alignment? Yes No Explain:
U a)
CD }
a3
. Creeks at Private Drives: Do private driveways, drives, or streets cross drainage
▪ ways that serve Above-Project areas or are in public easements/ROW?
m z No Yes If"yes" provide information below.
C/3• x How many instances? Describe location and provide information below.
a) Location 1:
m
U
ED_ Location 2:
Q
es
Location 3:
i I For each location enter value for: 1 2 3
Design year passing without toping travelway?
I
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.
I
STORMWATER DESIGN GUIDELINES Page 19 of 26 APPENDIX. D:TECH. DESIGN SUMMARY
Effective February 2007 As Revised February 2009
1
SECTION IX
APPENDIX D - TECHNICAL DESIGN SUMMARY
Part 4— Drainage Concept and Design Parameters Continued (Page 4.11)
Stormwater Management Concept(continued)
Ple
Within Or Serving Subject Property(Phase, or Site) (continued)
Named Regulatory Watercourses(&Tributaries): Are culverts proposed on these
facilities? X No Yes, then provide full report documenting assumptions,
criteria, analysis, computer programs, and study findings that support proposed Roo
design(s). Is report provided? Yes No If"no", explain:
U,
Arterial or Major Collector Streets: Will culverts serve these types of roadways?
X No Yes How many instances? For each identify the
location and provide the information below.
en 15_
Instance 1:
>- O we
°a,' Instance 2:
x
o Instance 3:
C
0 iYlt
o .2 Yes or No for the 100-year design flow: 1 2 3
o Headwater WSE 1 foot below lowest curb top?
Spread of headwater within ROW or easement? .r
Is velocity limited per conditions (Table C-11)?
c Explain any"no" answer(s):ul
corri
o c
U .0
(6 U U
O
o :n Minor Collector or Local Streets: Will culverts serve these types of streets?
c _ No X Yes How many instances? 2 for each identify the
a a�
location and provide the information below:
tz' �, Instance 1: Culvert #1 on Makawee Lane
mc Instance 2: Culvert #2 on Chaco Canyon Drive PIP
U o Instance 3:
«r
cFor each instance enter value, or"yes"/"no"for 1 2 3
U CIS
a) c Design yr. headwater WSE 1 ft. below curb top? Yes Yes
< �, 100-yr. max. depth at street crown 2 feet or less? Yes Yes
E Product of velocity(fps)&depth at crown (ft)_ ? 0 0
Is velocity limited per conditions (Table C-11)? Yes Yes
Limit of down stream analysis (feet)? 50' 50'
Explain any"no" answers:
U1
STORMWATER DESIGN GUIDELINES Page 20 of 26 APPENDIX. D:TECH. DESIGN SUMMARY
Effective February 2007 As Revised February 2009
U,
I
I SECTION IX
APPENDIX D — TECHNICAL DESIGN SUMMARY
r Part 4— Drainage Concept and Design Parameters Continued (Page 4.12)
l
Stormwater Management Concept (continued)
I 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.
I Do culverts and travelways intersect at 90 degrees? X Yes No If not,
identify location(s)and intersect angle(s), and justify the design(s):
I
Does drainage way alignment change within or near limits of culvert and surfaced
approaches thereto? X No Yes If"yes" identify location(s), describe
Ichange(s), and justification:
IAre flumes or conduit to discharge into culvert barrel(s)? X No Yes If yes,
identify location(s)and provide justification:
I
Are flumes or conduit to discharge into or near surfaced approaches to culvert ends?
I
2 x No Yes If"yes" identify location(s), describe outfall design treatment(s):
c
c
0
0
I co
> Is scour/erosion protection provided to ensure long term stability of culvert structural
c� components, and surfacing at culvert ends? X Yes No If"no" Identify
Ilocations and provide justification(s):
I
Will 100-yr flow and spread of backwater be fully contained in street ROW, and/or
drainage easements/ROW? X Yes No if not,why not?
I
Do appreciable hydraulic effects of any culvert extend downstream or upstream to
I neighboring land(s) not encompassed in subject property? X No Yes If
"yes"describe location(s)and mitigation measures:
I
Are all culvert designs and materials in compliance with B-CS Tech. Specifications?
IX Yes No If not, explain in Special Design Section of this Part.
I
STORMWATER DESIGN GUIDELINES Page 21 of 26 APPENDIX. D:TECH. DESIGN SUMMARY
Effective February 2007 As Revised February 2009
SECTION IX
APPENDIX D — TECHNICAL DESIGN SUMMARY
Part 4— Drainage Concept and Design Parameters Continued (Page 4.13)
Stormwater Management Concept (continued)
Within Or Serving Subject Property(Phase, or Site) (continued)
. bridge included in plans for subject property project? No Yes
If"ye-" .rovide the following information.
Name(s)a • functional classification of the roadway(s)? i■11
What drainage way(s) is to be , sed?
A full report supporting al aspects of the proposed bridge(s tructural, geotechnical,
hydrologic, and hydr.. is factors)must accompany this summa " eport. Is the report
provided? es No If"no"explain:
Is a Stormwater Provide a general description of planned techniques:
w Pollution Prevention Hay Bale Barriers and Rock Dams will serve as the
Plan (SW3P) main protection against stormwater pollution. The
C� established for
Contractor shall use any other means necessary
o project construction?
throughout construction.
No X Yes
3
Special Designs—Non-Traditional Methods
Are any non-traditional methods (aquatic echosystems, wetland-type detention, natural stream U
replication, BMPs for water quality, etc.) proposed for any aspect of subject property project?
X No Yes If"yes" list general type and location below.
ON
UN
'Provide1
full report about the proposed special design(s) including rationale for use and
3
expected be - • Report must substantiate that stormwater management .••-. es will not
be compromised, an. . •..intenance cost will not exceed thos- • ..itional design
solution(s). Is report provided? Yes no"explain:
a::
3
U
STORMWATER DESIGN GUIDELINES Page 22 of 26 APPENDIX. D:TECH. DESIGN SUMMARY
Effective February 2007 As Revised February 2009 wit
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)
err .ecial Designs—Deviation From B-CS Technical Specifications
If a design(s)or material(s)of traditional runoff-handling facilities deviate from provisions of
B-CS -chnical Specifications, check type facility(ies) and explain by specific detail eleme .
De = tion elements Drain system elements Channel features
Culve eatures Swales Ditches Inlets • tfalls
*` Valley gut s Bridges (explain in bridge report)
mr In table below briefly is-ntify specific element,justification for deviation(s).
Specific Detail Eleme Justification for Deviation (attach add' 'anal sheets if needed)
ram
1)
taw
2)
NMI
3)
4)
5)
Have elements been co. :inated with the City Engineer or her/his des ee? For each item
above provide"yes" .- no", action date, and staff name:
i 1)
.«. 2)
3)
4)
OW Design Parameters
«. Hydrology
Is a map(s)showing all Design Drainage Areas provided? X Yes No
Briefly summarize the range of applications made of the Rational Formula:
For the Rational Formula we assumed residential areas had a
runoff coefficient of 0.5 for large residential or estate lots.
alb
What is the size and location of largest Design Drainage Area to which the Rational Formula
.ft has been applied? 18.35 acres Location (or identifier): Ditch Line Culvert #2
aw
ow
STORMWATER DESIGN GUIDELINES Page 23 of 26 APPENDIX. D:TECH. DESIGN SUMMARY
Effective February 2007 As Revised February 2009
ww
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? ""
X No Yes In approximately what percent of Design Drainage Areas?
ON
As to intensity-duration-frequency and rain depth criteria for determining runoff flows, were any
criteria other than those provided in these Guidelines used? X No Yes If"yes" .rr
identify type of data, source(s), and where applied:
loso
IOW
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. O,
Feature Analysis Year(s) Design Year
Stors stem for arterial and collector streets
Storm drain system for eets
Open channels — 1.111
Swale/buried conduit co .•.-. on in lieu of channel
Go
Swa -
Roadside ditches and culverts serving them 2,5,10,25,50,100 25 & 100
0111
De I`ties: spillway crest and its outfall
--------------
Detention facilities: .. - and conveyance structure(s)
Detention facilities: volume when ou - , aged
Culverts serving private drives or str--
Culverts serving pu ways
Bri .-Trovide in bridge report.
Hydraulics
What is the range of design flow velocities as outlined below?
Design flow velocities; 25 year Gutters Conduit Culverts Swales Channels .a
Highest(feet per second) 8.43
Lowest(feet per second) 6.57
mi
Streets and Storm Drain Systems Provide the summary information outlined below:
Roughness coefficients used: For street gutters: NA
For conduit type(s) RCP 0.014 Coefficients:
I
STORMWATER DESIGN GUIDELINES Page 24 of 26 APPENDIX. D:TECH. DESIGN SUMMARY
Effective February 2007 As Revised February 2009
U
iirn
[
SECTION IX
APPENDIX D - TECHNICAL DESIGN SUMMARY
IPart 4— Drainage Concept and Design Parameters Continued (Page 4.16)
Design Parameters(continued)
I Hydraulics(continued)
' eet and Storm Drain Systems (continued)
For th- ollowing, are assumptions other than allowable per Guidelines?
I Inlet coe I '-nts? No Yes Head and friction losses No Yes
Explain any"y- "answer:
IIn conduit is velocity general " ' creased in the downstream direr on? Yes No
Are elevation drops provided at in : s, manholes, and juncti• boxes? Yes No
1 Explain any"no" answers:
I Are hydraulic grade lines calculated and own for •,..ign storm? Yes No
For 100-year flow conditions? es No 'lain any"no" answers:
LWhat tailwater conditi• s were assumed at outfall point(s)of the storm • .in system? Identify
each location and - plain:
i
Open Channels If a HEC analysis is utilized, does it follow Sec VI.F.5.a? Yes No
1 Ili Outside of straight sections, is flow regime within limits of sub-critical flow? x Yes No
If"no" list locations and explain:
Culverts If plan sheets do not provide the following for each culvert, describe it here.
r
For each design discharge, will operation be outlet(barrel)control or inlet control?
All culverts will be inlet controlled.
I
Entrance,friction and exit losses:
IA0.5 entrance and exit loss coefficients are used for sloped end treatments
and square edged headwalls with wingwalls.
1 Bridges Provide all in bridge report
I
I STORMWATER DESIGN GUIDELINES Page 25 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 4.17)
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
Open Office Calculator Spreadsheet
1/11
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 Ill, Paragraph C3.
Part 6— Conclusions and Attestation
um
Conclusions
Add any concluding information here: ISI
The Indian Lakes Subdivision, Phase 21 will have no adverse impact to downstream mi
properties and conforms to the overall subdivision report.
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 rri
required by any and all state and federal regulatory agencies for the proposed drainage
improvements have been issued or fall under applicable general permits."
(Affix Seal)
Licensed Professional Engineer
State of Texas PE No.
nu
STORMWATER DESIGN GUIDELINES Page 26 of 26 APPENDIX. D:TECH. DESIGN SUMMARY
Effective February 2007 As Revised February 2009 mo
6
EXHIBIT B
Drainage Area Map
. 1
I
1
IDrainage Report
Indian Lakes, Phase 21
1
1
1
1
1
1
1
1
1
1
1
1
1
1
EXHIBIT C- 1
Rational Method Calculations
I
I
I
I
I
I
Drainage Report
Indian Lakes, Phase 21
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
O
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I
I
I
I
I
EXHIBIT C-2
Culvert Sizing Calculations
I
I
I
I
1
Drainage Report
Indian Lakes, Phase 21
I
I
I
I
I
I
I
I
I
I
I
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DRAINAGE REPORT
FOR
INDIAN LAKES SUBDIVISION
PHASE 21
March 2015
PREPARED FOR:
SMILING MALLARD DEVELOPMENT, LTD.
3608 EAST 29TH STREET
BRYAN, TEXAS 77802
979-846-4384
I is
MBESI No. 10620048
& McCLURE & BROWNE ENGINEERING/SURVEYING, INC.
1008 Woodcreek Dr.,Suite 103•College Station,Tx.77845• (979)693-3838 Engineer Reg.No. F-458
Survey Reg.No. 101033-00
I
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Indian Lakes Subdivision, Phase 21
Stormwater Management Technical Design Summary Report
MBESI No. 10620048
PART 1 —Executive Summary Report
Section 1 —Contact Information
Project Designer: McClure and Browne Engineering and Surveying, Inc.
I 1008 Woodcreek Drive, Suite 103
College Station, TX 77845
979-693-3838
IProject Developer: Smiling Mallard Development, Ltd.
3608 East 29th Street
IBryan, Texas 77802
Section 2—General Information and Project Location
This development is the 21" phase of a multi-phase subdivision. Phase 21 consists of 12 lots. The
phase is located in the Indian Lakes Village which is down Arrington Rd. approximately 2 miles from
I the Arrington Rd./William D. Fitch Pkwy intersection. Phase 21 lies in the northeast portion of the
subdivision near the intersection of Mesa Verde Drive and Chaco Canyon Drive. The entire
subdivision has been analyzed in the initial drainage report submitted in September, 2000. The
Idevelopment is located within the ETJ of College Station.
I The project site is in the Peach Creek watershed. According to the Flood Insurance Rate Maps for
Brazos County, Texas and incorporated area, Map Number 48041C0350E effective May 16, 2012; no
portion of this property is located in a 100-year flood hazard area.
Culvert pipe and ditch sizing calculations are shown with this submittal.
I The culverts and ditches peak runoffs were found using the Rational Method. A runoff coefficient (c) of
0.50 was used for residential areas since all the lots have an area greater than 1 acre. The ditches along
the proposed roadways are uniform throughout the project. The ditch profiles along all proposed
I roadways were determined using the largest ditch drainage area found for Phase 21. The culverts and
ditches were analyzed using an Excel Spreadsheet which utilizes Manning's Equation for the analysis.
ISection 3 —Reference
Exhibit A Technical Design Summary
, I Exhibit B Drainage Area Map
Exhibit C-1 Rational Method Calculations
Exhibit C-2 Culvert Sizing Calculations
IExhibit C-3 Ditch Capacity Calculations
I
Drainage Report
IN Indian T.akcc Phase 21
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E
EXHIBITS
C
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,, E
,, I
, E
Drainage Report
Indian Lakes, Phase 21
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EXHIBIT A
Technical Design Summary
Drainage Report
Indian Lakes, Phase 21
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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
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.
111
beprovided via the forms provided in this
Note: Parts 2 through 6 are to
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
ito proposed project phases. This paragraph should also include reference to
applications that are in process with either City: plat(s), site plans, zoning requests,
STORMWATER DESIGN GUIDELINES Page 1 of 26 APPENDIX. D:TECH. DESIGN SUMMARY
Effective February 2007 As Revised February 2009
SECTION IX
APPENDIX D - TECHNICAL DESIGN SUMMARY
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 wo
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. Thegeneralplan for managing stormwater in the entire
g g 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 "mak
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.
voiN
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 41+
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.
we
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: so
"One -page drainage report dated , one set of
construction drawings ( sheets) dated , and a
-page specifications document dated comprise "1°
the drainage report for this project."
wa
STORMWATER DESIGN GUIDELINES Page 2 of 26 APPENDIX. D:TECH. DESIGN SUMMARY
Effective February 2007 As Revised February 2009
SECTION IX
APPENDIX D - TECHNICAL DESIGN SUMMARY
IPart 2 — Project Administration Start (Page 2.1)
Engineering and Design Professionals Information
I Engineering Firm Name and Address: Jurisdiction
City: Bryan
McClure & Browne Engineering/Surveying, Inc.
1008 Woodcreek Drive, Suite 103 X College Station
I College Station, Texas 77845 Date of Submittal:
(979)693-3838
Lead Engineer's Name and Contact Info.(phone, e-mail, fax): Other:
Jeffery L. Robertson, P.E.
Supporting Engineering/Consulting Firm(s): Other contacts:
Developer/Owner/Applicant Information
Developer/Applicant Name and Address: Phone and e-mail:
Smiling Mallard Development, Ltd. (979) 846-4384
3608 East 29th Street
Bryan, Texas 77802
P" Property Owner(s) if not Developer/ Applicant(& address): Phone and e-mail:
it
I
Project Identification
Development Name: Indian Lakes, Phase 21
Is subject property a site project, a single-phase subdivision, or part of a multi-phase subdivision?
IMulti-phase Subdivision If multi-phase, subject property is phase 21 of .
Legal description of subject property(phase) or Project Area:
(see Section II, Paragraph B-3a)
Oa
Indian Lakes, Phase 21
I
If subject property (phase) is second or later phase of a project, describe general status of all
earlier phases. For most recent earlier phase Include submittal and review dates.
i The project is the 21st phase of a multi phase subdivision. At this time the first phase has
been built. Phase 1 was submitted in September, 2000 and consisted of 58 lots. The most
recent phase submitted was Ph. 19.
General Location of Project Area, or subject property (phase):
Project site is located near the intersection of Mesa Verde Drive and Chaco Canyon Drive
in College Station, Texas.
II In City Limits? Extraterritorial Jurisdiction (acreage):
Bryan: acres. Bryan: College Station: 31.52
1 College Station: acres. Acreage Outside ETJ:
ISTORMWATER DESIGN GUIDELINES Page 3 of 26 APPENDIX. D:TECH. DESIGN SUMMARY
Effective February 2007 As Revised February 2009
el
SECTION IX
APPENDIX D - TECHNICAL DESIGN SUMMARY
Part 2 — Project Administration Continued (page 2.2)
Project Identification (continued)
Roadways abutting or within Project Area or Abutting tracts, platted land, or built
subject property: developments:
fig
Mesa Verde Drive & Chaco Canyon Drive Indian Lakes Phase 5, Indian Lakes Phase 19,
& Undeveloped Land
110
Named Regulatory Watercourse(s) &Watershed(s): Tributary Basin(s):
The nearest tributary is Peach Creek S.
Phase 21 is located in the Peach Creek Watershed. Tributary 7.2 (See FEMA Map 48041C0350E)
Plat Information For Project or Subject Property (or Phase)
Preliminary Plat File#: Final Plat File#: Date:
Name: Pending Approval Status and VoI/Pg: Pending Approval
If two plats, second name: File#: 1111
Status: Date: met
Zoning Information For Project or Subject Property (or Phase)
Zoning Type: Existing or Proposed? Case Code: ern
Case Date Status:
11111,
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:
gem
so
Preliminary Report Required? Submittal Date Review Date
Review Comments Addressed? Yes No In Writing? When?
Compliance With Preliminary Drainage Report. Briefly describe (or attach documentation
explaining) any deviation(s) from provisions of Preliminary Drainage Report, if any.
10
•Aw
SIR
wo
war
STORMWATER DESIGN GUIDELINES Page 4 of 26 APPENDIX. D:TECH. DESIGN SUMMARY
Effective February 2007 As Revised February 2009
SECTION IX
APPENDIX D - TECHNICAL DESIGN SUMMARY
Part 2 — Project Administration Continued (page 2.3)
Coordination For Project or Subject Property(or Phase)
Note: For any Coordination of stormwater matters indicated below, attach documentation
describing and substantiating any agreements, understandings, contracts, or approvals.
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?
i'"' Yes No X
Coordination with Summarize need(s) &actions taken (include contacts &dates):
Brazos County
Needed?
Yes No X
Coordination with Summarize need(s) &actions taken (include contacts &dates):
TxDOT Needed?
Yes No X
Coordination with Summarize need(s) & actions taken (include contacts &dates):
TAMUS Needed?
Yes No X
Permits For Project or Subject Property(or Phase)
As to stormwater management, are permits required for the proposed work from any of the entities
listed below? If so, summarize status of efforts toward that objective in spaces below.
Entity Permitted or Status of Actions (include dates)
a
Approved .
US Army Crops of
Engineers
No X Yes
US Environmental
Protection Agency
No X Yes
Texas Commission on A Stormwater Pollution Prevention Plan must be
taw Environmental Quality implemented prior to the start of construction
No Yes X according to TPDES General Permit No. TXR150000.
Brazos River
Authority
No X 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
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? Mr
Existing undeveloped land (Dense tree cover) . Existing impervious cover is
approximately 0 sf.
ON
Site Redevelopment of one platted lot, or two or more adjoining platted lots.
Development Building on a single platted lot of undeveloped land. "h
Project Building on two or more platted adjoining lots of undeveloped land. a�rr
(select all Building on a single lot, or adjoining lots, where proposed plat will not form
applicable) a new street(but may include ROW dedication to existing streets).
Other(explain):
Subdivision X Construction of streets and utilities to serve one or more platted lots.
Development Construction of streets and utilities to serve one or more proposed lots on ow
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 No,
Nature and drainage easements or ROW.
ow
Size of This phase of the subdivision includes 12 lots. The development
Proposed consists of approximately 1,593 LF of streets with 16' PUE on each
Project side of the streets ROW.
toi
Is any work planned on land that is not platted If yes, explain:
or on land for which platting is not pending? SIP
X No Yes
FEMA Floodplains
Is any part of subject property abutting a Named Regulatory Watercourse No X Yes '
(Section II, Paragraph B1) or a tributary thereof? --
Is any part of subject property in floodplain No Yes X Rate Map 48041C0350E 1
area of a FEMA-regulated watercourse?
ow
Encroachment(s) Encroachment purpose(s): Building site(s) Road crossing(s)
into Floodplain
areas planned'? Utility crossing(s) Other(explain):
No X U4
Yes
0.111
If floodplain areas not shown on Rate Maps, has work been done toward amending the FEMA- 418
approved Flood Study to define allowable encroachments in proposed areas? Explain.
a
mi
me
a
STORMWATER DESIGN GUIDELINES Page 6 of 26 APPENDIX. D:TECH. DESIGN SUMMARY
Imo
Effective February 2007 As Revised February 2009
I
I SECTION IX
APPENDIX D - TECHNICAL DESIGN SUMMARY
pik
Part 3 — Property Characteristics Continued (Page 3.2)
Hydrologic Attributes of Subject Property (or Phase)
I Has an earlier hydrologic analysis been done for larger area including subject property?
Reference the study (&date) here, and attach copy if not already in City files.
Yes Indian Lakes Subdivision; September, 2000
X
lib
Is the stormwater management plan for the property in substantial conformance with the
Ilk earlier study? Yes X No If not, explain how it differs.
it
i
ONW
No If subject property is not part of multi-phase project, describe stormwater management
plan for the property in Part 4.
I f, — 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.
r"
I x
t.
I
Do existing topographic features on subject property store or detain runoff? X No Yes
IDescribe them (include approximate size, volume, outfall, model, etc).
iAny known drainage or flooding problems in areas near subject property? X No Yes
Identify:
1
Based on location of study property in a watershed, is Type 1 Detention (flood control) needed?
I
(see Table B-1 in Appendix B)
Detention is required. X Need must be evaluated. Detention not required.
What decision has been reached? By whom?
Detention study during Phase 1.
1 boo
If the need for How was determination made?
Type 1 Detention
must be evaluated: Detention was required and is provided for the entire
Indian Lakes Subdivision. Phase 21 does not require
any additional detention.
1 li
>Vw
ISTORMWATER 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)
Hydrologic Attributes of Subject Property (or Phase) (continued)
Does subject property straddle a Watershed or Basin divide? X No Yes If yes, °
describe splits below. In Part 4 describe design concept for handling this.
Watershed or Basin Larger acreage Lesser acreage
414
1111
4110
Above-Project Areas(Section II, Paragraph B3-a)
Does Project Area (project or phase) receive runoff from upland areas? No x Yes 1111
Size(s) of area(s) in acres: 1) v.05 2) 3) 4) OS
Flow Characteristics (each instance) (overland sheet, shallow concentrated, recognizable
concentrated section(s), small creek (non-regulatory), regulatory Watercourse or tributary); ow
Overland flow to proposed ditch lines on Phase 21 streets.
ars
Flow determination: Outline hydrologic methods and assumptions:
The Rational Method was used for flow calculations and the post development
ai
land was treated as large acre residential tracts.
Does storm runoff drain from public easements or ROW onto or across subject property?
x No Yes If yes, describe facilities in easement or ROW:
S
Are changes in runoff characteristics subject to change in future? Explain
No, upstream land is already developed.
+®r
Conveyance Pathways (Section II, Paragraph C2)
Must runoff from study property drain across lower properties before reaching a Regulatory
Watercourse or tributary? No X Yes ow
Describe length and characteristics of each conveyance pathway(s). Include ownership of
property(ies).
Runoff from Ph. 21 will leave the phase and be discharged into existing *ma
tributaries of Peach Creek. The property is a future phase
OW
of the Indian Lakes Subdivision.
ISE
twr
SO
STORMWATER DESIGN GUIDELINES Page 8 of 26 APPENDIX. D:TECH. DESIGN SUMMARY
MIS
Effective February 2007 As Revised February 2009
S
SECTION IX
APPENDIX D - TECHNICAL DESIGN SUMMARY
Part 3 — Property Characteristics Continued (Page 3.4)
Hydrologic Attributes of Subject Property (or Phase) (continued)
00. 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)?
X No
Yes
Where runoff must cross lower properties, describe characteristics of abutting lower
property(ies). (Existing watercourses? Easement or Consent aquired?)
Pathway
Areas
Describe any built or improved drainage facilities existing near the property (culverts,
bridges, lined channels, buried conduit, swales, detention ponds, etc).
Nearby
Drainage Do any of these have hydrologic or hydraulic influence on proposed stormwater
Facilities design? X No Yes If yes, explain:
STORMWATER DESIGN GUIDELINES Page 9 of 26 APPENDIX. D:TECH. DESIGN SUMMARY
Effective February 2007 As Revised February 2009
SECTION IX
APPENDIX D - TECHNICAL DESIGN SUMMARY
Part 4— Drainage Concept and Design Parameters Start (Page 4.1)
Stormwater Management Concept
Discharge(s) From Upland Area(s)
xwo
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,
sow
flow section, or discharge point.
S
Discharge(s)To Lower Property(ies) (Section II, Paragraph El)
Does project include drainage features (existing or future) proposed to become public via ,
platting? X No Yes Separate Instrument? X No Yes
ire
Per Guidelines reference above, how will
runoff be discharged to neighboring Establishing Easements (Scenario 1)
y(ies)? Pre-development Release (Scenario 2)propertA!
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# )
41,
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.
I
1116,
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 AIN
documentation.
at
IOW
A
STORMWATER DESIGN GUIDELINES Page 10 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 4.2)
Stormwater 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
between What design and mitigation is used to compensate for increased runoff
Watersheds? from gaining basin or watershed?
X No
Yes
How will runoff from Project 1. With facility(ies) involving other development projects.
Area be mitigated to pre-
2. Establishing features to serve overall Project Area.
development conditions?
Select any or all of 1, 2, 3. X On phase (or site) project basis within Project Area.
and/or 3, and explain below.
1. Shared facility(type& location of facility; design drainage area served; relationship to size of
Project Area): (Attached Exhibit#
2. For Overall Project 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)?
-0
D
u)
c (1.)
c >- Are other Best Management Practices for reducing stormwater pollutants proposed?
No Yes Summarize type of BMP and extent of use:
cn
0)
(I) o
a z
If design of any runoff-handling facilities deviate from provisions of B-CS Technical
E_ X Specifications, check type facility(ies) and explain in later questions.
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 February 2009
SECTION IX
APPENDIX D - TECHNICAL DESIGN SUMMARY
Part 4— Drainage Concept and Design Parameters Continued (Page 4.3)
Stormwater Management Concept(continued)
Within Prosect Area Of Multi-Phase Project(continued)
Will Project Area include bridge(s) or culvert(s)? No x Yes Identify type and
general size and In which phase(s).
Culvert #1 - 2 24" RCP Pipes on Makawee Lane
Culvert #2 - 2 30" RCP Pipes on Chaco Canyon Drive
ow
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):
WIN
w
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): ,
es,
Mt
Identify whether each of the types of drainage features listed below are included, extent of use,
and general characteristics.
ow
Typical shape? Surfaces?
�• V-Shape Grass Iota
n w Steepest side slopes: Usual front slopes: Usual back slopes:
>- 4:1 4:1 4:1
a)
o x Flow line slopes: least 0.65% Typical distance from travelway: 11'
Varies (Attached Exhibit#_ )
typical greatest 3.15%
o0111
z
asso Are longitudinal culvert ends in compliance with B-CS Standard Specifications?
Yes No, then explain: All
a At intersections or otherwise, do valley gutters cross arterial or collector streets?
-E) 4— No Yes If yes explain:
o "O
L
a) Are valley gutters proposed to cross any street away from an intersection?
aa) z No Yes Explain: (number of locations?)
m m x
ss
WO
STORMWATER DESIGN GUIDELINES Page 12 of 26 APPENDIX. D:TECH. DESIGN SUMMARY
Effective February 2007 As Revised February 2009
4111
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 Usual Greatest
Are inlets recessed on arterial and collector streets? Yes No If"no",
w identify where and why.
Will inlets capture 10-year design stormflow to prevent flooding of intersections (arterial
two with arterial or collector)? Yes No If no, explain where and why not.
C'.
a)
Will inlet size and placement prevent exceeding allowable water spread for 10-year
design storm throughout site (or phase)? Yes No If no, explain.
a)
low `6 Sag curves: Are inlets placed at low points? Yes No Are inlets and
conduit sized to prevent 100-year stormflow from ponding at greater than 24 inches?
Yes No Explain "no" answers.
a)
Will 100-yr stormflow be contained in combination of ROW and buried conduit on
w.
whole length of all streets? Yes No If no, describe where and why.
w
Do designs for curb, gutter, and inlets comply with B-CS Technical Specifications?
,... Yes No If not, describe difference(s) and attach justification.
ate Are any 12-inch laterals used? No Yes Identify length(s) and where
used.
rr.
amiPipe runs between system
Typical Longest
a> access points (feet):
aa) Are junction boxes used at each bend? Yes No If not, explain where
,N, and why.
toc
low
o
� Z
E x
«.� ° Are downstream soffits at or below upstream soffits? Least amount that hydraulic
Yes No If not, explain where and why: grade line is below gutter line
(system-wide):
+.q STORMWATER DESIGN GUIDELINES Page 13 of 26 APPENDIX. D:TECH. DESIGN SUMMARY
Effective February 2007 As Revised February 2009
SECTION IX
APPENDIX D — TECHNICAL DESIGN SUMMARY
tsk
Part 4— Drainage Concept and Design Parameters Continued (Page 4.5)
Stormwater Management Concept(continued)
Within Or Serving Subject Property(Phase, or Site) (continued)
Describe watercourse(s), or system(s) receiving system discharge(s) below
U (include design discharge velocity, and angle between converging flow lines). fotF
0 1) Watercourse (or system), velocity, and angle?
O -!
ami E 2) Watercourse (or system), velocity, and angle?
c 4• 2
o
c
E
E �' 3)Watercourse (or system), velocity, and angle?
5
• 70 O AP1
° :
n
E 1-1; For each outfall above, what measures are taken to prevent erosion or scour of
receiving and all facilities at juncture?
:: 1) wr+
co
a) 2) apt
3)
Are swale(s) situated along property lines between properties? No Yes wN
Number of instances: For each instance answer the following questions. err
Surface treatments (including low-flow flumes if any):
AIF
a>
O)
} Flow line slopes (minimum and maximum): OP
0
ai o
Z Outfall characteristics for each (velocity, convergent angle, & end treatment).
U)
mx
Q Will 100-year design storm runoff be contained within easement(s) or platted drainage
ROW in all instances? Yes No If"no" explain:
et
so
et
r.r
et
STORMWATER DESIGN GUIDELINES Page 14 of 26 APPENDIX. D:TECH. DESIGN SUMMARY
Effective February 2007 As Revised February 2009
A
SECTION IX
APPENDIX D - TECHNICAL DESIGN SUMMARY
Part 4— Drainage Concept and Design Parameters Continued (Page 4.6)
Stormwater Management Concept(continued)
00.
rr
Within Or Serving Subject Property(Phase,or Site) (continued)
Are roadside ditches used? No X Yes If so, provide the following:
rIs 25-year flow contained with 6 inches of freeboard throughout? X Yes No
1,2 Are top of banks separated from road shoulders 2 feet or more? X Yes No
`ow Are all ditch sections trapezoidal and at least 1.5 feet deep? Yes X No
For any"no" answers provide location(s) and explain:
All Ditches are V-shaped and at least 2 ' deep
Yr CL
If conduit is beneath a swale, provide the following information (each instance).
Oro Instance 1 Describe general location, approximate length:
>- Is 100-year design flow contained in conduit/swale combination? Yes No
If "no" explain:
Ia)
N
U
o as Space for 100-year storm flow? ROW Easement Width
41%* Z c Swale Surface type, minimum Conduit Type and size, minimum and maximum
X Iis and maximum slopes: slopes, design storm:
u
i ,
" i co Inlets Describe how conduit is loaded (from streets/storm drains, inlets by type):
c
co
s
U L
c
c
O o Access Describe how maintenance access is provided (to swale, into conduit):
o E
E
0
.c Instance 2 Describe general location, approximate length:
E
co
• N
c Is 100-year design flow contained in conduit/swale combination? Yes No
o If "no" explain:
f° a
c
imav E 15
Space for 100-year storm flow? ROW Easement Width
o c
Swale Surface type, minimum Conduit Type and size, minimum and maximum
.e» °3
as and maximum slopes: slopes, design storm:
c co
U0.gi
Inlets Describe how conduit is loaded (from streets/storm drains, inlets by type):
.• 3
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 February 2009
SECTION IX
APPENDIX D - TECHNICAL DESIGN SUMMARY
040
Part 4— Drainage Concept and Design Parameters Continued (Page 4.7)
Stormwater Management Concept(continued)
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:
c
F
E xx
o
Is 100-year design flow contained in swale? Yes No Is swale wholly
Cwithin drainage ROW? Yes No Explain "no" answers:
a>
Access Describe how maintenance access is provide:
L o
z
O
X
-a Instance 2 Describe general location, approximate length, surfacing:
m
Com•
a)
3 Is 100-year design flow contained in swale? Yes No Is swale wholly
c within drainage ROW? Yes No Explain "no" answers:
3 O
TEI
rn
• Q' Access Describe how maintenance access is provided:
UNO
0.
Instance 3,4, etc. If swales are used in more than two instances, attach sheet
1110
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 mi
shaped, see"Swales" in this Part. If creating side banks, provide information below.
�.
a:i .E Will design replicate natural channel? Yes No If"no", for each instance
o a. describe section shape &area, flow line slope (min. & max.), surfaces, and 100-year
o w design flow, and amount of freeboard: "'
Instance 1: .04
ca
}a
E
a)
Instance 2:
n
E
z
c X Instance 3:
ca
t
0
v�p
STORMWATER DESIGN GUIDELINES Page 16 of 26 APPENDIX. D:TECH. DESIGN SUMMARY
Effective February 2007 As Revised February 2009
S
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.
rt
a>
c
Watercourses (and tributaries): Aside from fringe changes, are Regulatory
• Watercourses proposed to be altered? No Yes Explain below.
• Submit full report describing proposed changes to Regulatory Watercourses. Address
• existing and proposed section size and shape, surfaces, alignment, flow line changes,
> length affected, and capacity, and provide full documentation of analysis procedures
2 and data. Is full report submitted? Yes No If"no" explain:
110, CL
E
a)
it 0 All Proposed Channel Work: For all proposed channel work, provide information
requested in next three boxes.
If design is to replicate natural channel, identify location and length here, and describe
design in Special Design section of this Part of Report.
Will 100-year flow be contained with one foot of freeboard? Yes No If
not, identify location and explain:
rwe
Are ROW/easements sized to contain channel and required maintenance space?
Yes No If not, identify location(s) and explain:
View
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
agi
Part 4— Drainage Concept and Design Parameters Continued (Page 4.9)
ilk
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% rw
100-yr volume:free flow& plugged
Design discharge (10 yr&25 yr) si
Spillway crest at 100-yr WSE? yes no _yes no low
Berms 6 inches above plugged WSE? yes no _yes no
1�N
Explain any"no" answers:
.ro
U)
>
om#
For each facility what is 25-yr design Q, and design of outlet structure?
Facility 1:
Z Facility 2:
X Do outlets and spillways discharge into a public facility in easement or ROW?
Facility 1: Yes No Facility 2: Yes No
If"no" explain:
U)
a
0
For each, what is velocity of 25-yr design discharge at outlet? & at spillway? w.v
Facility 1: & Facility 2: &
Are energy dissipation measures used? No Yes Describe type and
ca
Ni
location: vo:
c
0
N,
m
o ter;
For each, is spillway surface treatment other than concrete? Yes or no, and describe:
Facility 1: 0111
Facility 2: rr.
For each, what measures are taken to prevent erosion or scour at receiving facility?
01111
Facility 1:
.rw
Facility 2:
If berms are used give heights, slopes and surface treatments of sides. Ni
Facility 1: .r,
Facility 2:
rr
Ni
STORMWATER DESIGN GUIDELINES Page 18 of 26 APPENDIX. D:TECH. DESIGN SUMMARY
Effective February 2007 As Revised February 2009
Ni
SECTION IX
APPENDIX D - TECHNICAL DESIGN SUMMARY
Part 4— Drainage Concept and Design Parameters Continued (Page 4.10)
Stormwater Management Concept(continued)
Within Or Serving Subject Property(Phase, or Site) (continued)
Do structures comply with B-CS Specifications? Yes or no, and explain if"no":
U)
Facility 1;
m
Facility 2:
40. Cam.
o c
o
C U
N
oFor additional facilities provide all same information on a separate sheet.
Are parking areas to be used for detention? No Yes What is
o.�
maximum depth due to required design storm?
Roadside Ditches: Will culverts serve access driveways at roadside ditches?
No x Yes If"yes", provide information in next two boxes.
Will 25-yr. flow pass without flowing over driveway in all cases? 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:
�.
U,
rn
oAre culverts parallel to public roadway alignment? Yes No Explain:
L
Or U N
a)
f6
eA* >
Creeks at Private Drives: Do private driveways, drives, or streets cross drainage
+rer ways that serve Above-Project areas or are in public easements/ROW?
0
a z No Yes If"yes" provide information below.
N x 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.
Wow
STORMWATER DESIGN GUIDELINES Page 19 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 4.11)
Stormwater Management Concept(continued)
Within Or Serving Subject Property(Phase, or Site) (continued)
Named Regulatory Watercourses (&Tributaries): Are culverts proposed on these
facilities? X No Yes, then provide full report documenting assumptions,
criteria, analysis, computer programs, and study findings that support proposed
design(s). Is report provided? Yes No If"no", explain:
m Arterial or Major Collector Streets: Will culverts serve these types of roadways?
X No Yes How many instances? For each identify the
a) location and provide the information below.
a Instance 1:
a mss,
,L), Instance 2:
x
0 Instance 3:
o . Yes or No for the 100-year design flow: 1 2 3
o Headwater WSE 1 foot below lowest curb top?
.a Spread of headwater within ROW or easement?
- E
Is velocity limited per conditions (Table C-11)?
.c E Explain any"no" answer(s):
o c
U O
co U
O
o Minor Collector or Local Streets: Will culverts serve these types of streets?
S _—
No X Yes How many instances? 2 for each identify the mit
sa
o location and provide the information below:
• (1)
- Q Instance 1: Culvert #1 on Makawee Lane
w c Instance 2: Culvert #2 on Chaco Canyon Drive *.
cn (6
U) o Instance 3: „a,
a> a)
U 0 For each instance enter value, or"yes"I"no"for: 1 2 3
a, Design yr. headwater WSE 1 ft. below curb top? Yes
Yes
< .a 100-yr. max. depth at street crown 2 feet or less? Yes
Yes
E Product of velocity (fs) &depth at crown (ft) _ ? 0
0 1111
o Is velocity limited per conditions (Table C-11)? Yes Yes
Limit of down stream analysis (feet)? 50' 50'
Explain any"no" answers: fra
STORMWATER DESIGN GUIDELINES Page 20 of 26 APPENDIX. D:TECH. DESIGN SUMMARY 116
Effective February 2007 As Revised February 2009
S
SECTION IX
APPENDIX D - TECHNICAL DESIGN SUMMARY
Part 4— Drainage Concept and Design Parameters Continued (Page 4.12)
Stormwater Management Concept(continued)
Within Or Serving Subject Property(Phase, or Site) (continued)
All Proposed Culverts: For all proposed culvert facilities (except driveway/roadside
ditch intersects) provide information requested in next eight boxes.
Do culverts and travelways intersect at 90 degrees? X Yes No If not,
identify location(s) and intersect angle(s), and justify the design(s):
Does drainage way alignment change within or near limits of culvert and surfaced
approaches thereto? X No Yes If"yes" identify location(s), describe
change(s), and justification:
Are flumes or conduit to discharge into culvert barrel(s)? X No Yes If yes,
identify location(s) and provide justification:
_ Are flumes or conduit to discharge into or near surfaced approaches to culvert ends?
'""° X No Yes If"yes" identify location(s), describe outfall design treatment(s):
m
0
0
Cl)
> Is scour/erosion protection provided to ensure long term stability of culvert structural
0 components, and surfacing at culvert ends? X Yes No If"no" Identify
locations and provide justification(s):
®11. Will 100-yr flow and spread of backwater be fully contained in street ROW, and/or
drainage easements/ROW? X Yes No if not, why not?
a-
Oho
Do appreciable hydraulic effects of any culvert extend downstream or upstream to
neighboring land(s) not encompassed in subject property? X No Yes If
"yes" describe location(s) and mitigation measures:
Are all culvert designs and materials in compliance with B-CS Tech. Specifications?
X Yes No If not, explain in Special Design Section of this Part.
STORMWATER DESIGN GUIDELINES Page 21 of 26 APPENDIX. D:TECH. DESIGN SUMMARY
Effective February 2007 As Revised February 2009
SECTIONI IX
APPENDIX D - TECHNICAL DESIGN SUMMARY
0
Part 4— Drainage Concept and Design Parameters Continued (Page 4.13)
wit
Stormwater Management Concept(continued)
Within Or Serving Subject Property(Phase, or Site) (continued)
Is a bridge included in plans for subject property project? No __Yes •w
If"yes" provide the following information.
Name(s) and functional classification of the roadway(s)? Ai
0
What drainage way(s) is to be crossed?
N
4)
a)
AML
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:
Pollution Prevention
Hay Bale Barriers and Rock Dams will serve as the 111
Tcs Plan (SW3P) mainprotection against stormwater
C� established for g pollution. The Ni
Contractor shall use any other means necessary
project construction?
throughout construction.
__No x Yes
41 OP
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?
x No _ Yes If"yes" list general type and location below.
0
OP
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: PP
0
wo
NS
STORMWATER DESIGN GUIDELINES Page 22 of 26 APPENDIX. D:TECH. DESIGN SUMMARY
Effective February 2007 As Revised February 2009
SECTION IX
il" APPENDIX D — TECHNICAL DESIGN SUMMARY
IPart 4— Drainage Concept and Design Parameters Continued (Page 4.14)
Stormwater Management Concept(continued)
I 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
I 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)
C
3)
4
[ i 5)
I 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)
1 5)
Design Parameters
1111 Hydrology
Is a map(s) showing all Design Drainage Areas provided? X Yes No
Briefly summarize the range of applications made of the Rational Formula:
1
For the Rational Formula we assumed residential areas had a
runoff coefficient of 0.5 for large residential or estate lots.
I
What is the size and location of largest Design Drainage Area to which the Rational Formula
1 has been applied? 18.35 acres Location (or identifier): Ditch Line Culvert #2
ISTORMWATER DESIGN GUIDELINES Page 23 of 26 APPENDIX. D:TECH. DESIGN SUMMARY
Effective February 2007 As Revised February 2009
OM
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? to,
X No Yes In approximately what percent of Design Drainage Areas?
41111
As to intensity-duration-frequency and rain depth criteria for determining runoff flows, were any
criteria other than those provided in these Guidelines used? X No Yes If"yes"
identify type of data, source(s), and where applied:
St
mat.w�
At
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. at
Feature Analysis Year(s) Design Year
Storm drain system for arterial and collector streets
Storm drain system for local streets
Open channels
Swale/buried conduit combination in lieu of channel
Swales
.r>
Roadside ditches and culverts serving them 2,5,10,25,50, 100 25 & 100
AM
Detention facilities: spillway crest and its outfall
gap
Detention facilities: outlet and conveyance structure(s)
Detention facilities: volume when outlet plugged
Culverts serving private drives or streets +w;
Culverts serving public roadways
Bridges: provide in bridge report.
rrr+
Hydraulics
What is the range of design flow velocities as outlined below?
Design flow velocities; 25 year Gutters Conduit Culverts Swales Channels vie
Highest(feet per second) 8.43
Lowest(feet per second) 6 57
wr+
Streets and Storm Drain Systems Provide the summary information outlined below:
Roughness coefficients used: For street gutters: NA It
For conduit type(s) RCP 0.014 Coefficients:
St
vas
STORMWATER DESIGN GUIDELINES Page 24 of 26 APPENDIX. D:TECH. DESIGN SUMMARY .w
Effective February 2007 As Revised February 2009
S
SECTION IX
APPENDIX D - TECHNICAL DESIGN SUMMARY
Part 4— Drainage Concept and Design Parameters Continued (Page 4.16)
Design Parameters(continued)
Hydraulics (continued)
Street and Storm Drain Systems (continued)
For the following, are assumptions other than allowable per Guidelines?
Inlet coefficients? No Yes Head and friction losses No Yes
Explain any"yes" answer:
01.10.
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? x Yes No
If"no" list locations and explain:
Culverts If plan sheets do not provide the following for each culvert, describe it here.
For each design discharge, will operation be outlet(barrel) control or inlet control?
All culverts will be inlet controlled.
w�.
Ww
Entrance, friction and exit losses:
A 0.5 entrance and exit loss coefficients are used for sloped end treatments
— and square edged headwalls with wingwalls.
0.
Bridges Provide all in bridge report
err
STORMWATER DESIGN GUIDELINES Page 25 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 4.17)
Design Parameters(continued)
Computer Software4111)
What computer software has been used in the analysis and assessment of stormwater owo
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 ark
version, any applicable patches and the publisher
wog
Open Office Calculator Spreadsheet
ILMI
iugo
IRO
Part 5— Plans and Specifications ie,
Requirements for submittal of construction drawings and specifications do not differ due to use of a
Technical Design Summary Report. See Section Ill, Paragraph C3.
Part 6 — Conclusions and Attestation
Conclusions
Add any concluding information here: in'
The Indian Lakes Subdivision, Phase 21 will have no adverse impact to downstream
properties and conforms to the overall subdivision report.
air
wr
Attestation MM
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 110
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 u
required by any and all state and federal regulatory agencies for;the propose4.,A, age
improvements have been issued or fall under applicable general permits." .e •°� '
itN•( (Affix Seal)1-• if OA- 7 ^
• t
Licen l. professional Engineer „c1::Fc7Y L. POBERT:0;% ,
,, � iiitC ri - 94745 s
State of Texas PE No. �� � L/
4 i� af.Nkl.G�'�`w
•
STORMWATER DESIGN GUIDELINES Page 26 of 26 APPENDIX. D:T H. DESIGN SUMMARY
Effective February 2007 As Revised February 2009
OP
Wu-
EXHIBIT B
Drainage Area Map
Drainage Report
Indian Lakes, Phase 21
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
Item
Woo
IOU
Mit
EXHIBIT C- 1
ofto Rational Method Calculations
WIWO
Drainage Report
Indian Lakes, Phase 21
1
1
1
i
1
1
1
1
1
1
1
1
1
1
1
1
1
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Culvert Sizing Calculations
L
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Indian Lakes, Phase 21
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r EXHIBIT C-3
Ditch Capacity Calculations
I
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Drainage Report
Indian Lakes, Phase 21
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