HomeMy WebLinkAboutDrainage ReportDRAINAGE SYSTEM REPORT FOR
CASTLEGATE II SUBDIVISION, SECTION 201
COLLEGE STATION, TEXAS
January 2012
Revised February 2010
Prepared by:
Phillips Engineering
4490 Castlegate Drive
College Station, Texas 77845
(979) 690 -3141
GENERAL INFORMATION AND BACKGROUND
Section 201 is the second phase being constructed in the Castlegate II Subdivision. It lies in the central
portion of the subdivision, and is adjacent to Section 200 to the west. It consists of 30 residential lots, and
includes an extension of Odell Lane, along with Egremont Court and a segment of Norwich Drive. All of
Section 201 lies within the Spring Creek Drainage Basin and will drain into the previously constructed
detention pond. That pond was designed to accommodate runoff from Section 201 and all assumptions
associated with its design are still valid. No additional detention is being proposed with Section 201.
Section 201 lies in one of the lowest portions of the Castlegate II development and certain accommodations
are necessary to make the utility systems work together. One of these involves the potential conflicts
between sanitary and storm sewer systems. Another is the pathway to get stormwater from the street
(Norwich Drive) to the detention pond. Initial designs involved lowering the storm drain system sufficiently
to get under the sewer lines, but this required the storm sewers to enter the detention pond below the normal
pool elevation and thus keep water in the pipes at all times. The current design reroutes the sewer lines
around the potential conflict area, thus allowing the storm sewers to remain at a higher elevation. The
portions of the storm drains that will remain inundated are now limited to short segments immediately
adjacent to the detention pond. These segments of the storm drain line will remain privately owned and be
covered with a private drainage easement.
DRAINAGE SYSTEM REPORT
General Hydraulic and Hydrologic Characteristics
Section 201 of the subdivision is located in a densely wooded portion of the subdivision. The topography is
gently sloping to the east toward the detention pond, and ultimately into the Spring Creek Tributary A2A.
Storm Drain Design Parameters
Street Design:
• Standard cross - section (3% cross - slope)
• Laydown curb
• Asphalt pavement
• Standard recessed curb inlets
T Methodology: TR 55
T Minimum 10 minutes
Design Storm Event: 10 -year
Pipe Materials: RCP and HDPE
Manning 's n Value: 0.013
Runoff Coefficients: 0.55 for surrounding development
Design Constraints:
Design Software:
Applicable Exhibits:
Max water depth:
Laydown curb = 4.5 in. or 0.38 ft.
Standard curb = 6 in. or 0.5 ft
Min flow velocity = 2.5 fps for pipes flowing full
Max flow velocity = 15 fps
100 -yr storm runoff maintained within the ROW (4 inches above curb)
AutoCAD 2012 w/ Civil 3D Hydraflow Storm Sewer Design Package
Exhibit H — Storm Sewer Drainage Area Map
Exhibit I — Time of Concentration Calculation Worksheet
Exhibit J — Gutter Depth Calculation Worksheet
Exhibit K — Inlet Size Computation Worksheet
Exhibit L — Hydraflow Pipe Analysis Summary (10 -yr and 100 -yr storms)
To the City Engineer for the City of College Station, Texas:
Re: The Castlegate II Subdivision, Section 201
Certification Statement
I have conducted a topographic review and field investigation of the existing and proposed
flow patterns for stormwater runoff from Castlegate II Subdivision, Section 201. At build -
out conditions allowable by zoning, restrictive covenant, or plat note, the stormwater flows
from the subject subdivision or site project will not cause any increase in flooding
conditions to the interior of existing building structures, including basement areas, for
storms of magnitude up through the 100 yr event.
—7, 9 .. .. ..
s d 6 5--g23
• v
Engineer's Si gnature Date Tx License No. * : • * I
soy KENT M. LAZA
65923 $
4 490.10;47
ALE
DRAINAGE AREA MAP
CASTLEGATE SUBDIVISION SECTION 201
COLLEGE STATION, TEXAS
PHILLIPS ENGINEERING
4490 Castlegate Drive
College Station, Texas 77845
(979)690 -3141 Fax: (979)690 -1041
TBPE Firm No. F -13130
NO
OATS
NOTES
DESCRIPTION
SCALE: AS SHOWN
PLOT F 12/23/201
DRAINAGE AREA MAP
CASTLEGATE SUBDIVISION SECTION 201
COLLEGE STATION, TEXAS
PHILLIPS ENGINEERING
4490 Castlegate Drive
College Station, Texas 77845
(979) 690 -3141 Fax (979) 690 -1041
TBPE Firm No. F -13130
P10
DATE
NOTES
oESC19P0aN
SCALE: AS SHOWN
PLOT DATE: 12/29/201
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SECTION IX
STORMWATER DESIGN GUIDELINES
Effective February 2007
APPENDIX D — TECHNICAL DESIGN SUMMARY
Start (Page 2.1)
Part 2 — Project Administration
Engineering and Design Professionals information
Jurisdiction
City: Bryan
✓ College Station
Engineering Firm Name and Address:
,p lei f i ps 1 iee
( t o o CG57115,k r
Lead Engineer's Name and Contact Info.(phone, e-mail, fax):
Kam ±l��a g -
igb - 1
Supporting Engineering / Consulting Firm(s):
Developer / Applicant Name and Address:
-b E Ion Me-4 ( LL C
L{ y A c C4s11e
54 , ?1C N 115
Property Owner(s) if not Developer / Applicant (& address):
In City Limits?
Bryan:
College Station:
acres.
, SCSI,
acres.
Date of Submittal:
Other:
Other contacts:
Developer / Owner/Applicant Information
Phone and e-mail:
�1 - - 7aSb
Phone and e-mail:
Project Identification
Development Name: C4Sji� p 4e Sh d,v�1
Sec�f /ah aC /
Is subject property a site projict, a single -phase subdivision, or part of a multi -phase subdivision?
nt,, t t dose. If multi - phase, subject property is phase ? of /( .
Legal description of subject property (phase) or Project Area:
(see Section 11, Paragraph B -3a)
f I S ft 7�9�:1 oZj
k 4, /1- }e�`n5O �ei� ✓C r
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.
t�0 ti5 CCASfruGfi'� / JJS n ow t' H i � . ;1 n( en _
General Location of Project Area, or subject property (phase): H ics Sv�
�n f P p (2 4e,Ar / 3
eAG -Oey no�i� �e o C � i
Extraterritorial Jurisdiction (acreage):
Bryan: College Station:
Acreage Outside ETJ:
1 - 4 “ - . . , , / f
Page 3 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
As Revised February 2009
SECTION IX
STORMWATER DESIGN GUIDELINES
Effective February 2007
APPENDIX D — TECHNICAL DESIGN SUMMARY
Page 4 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
As Revised February 2009
Part 2 — Project Administration I Continued (page 2.2)
Pro Identification (continued)
Roadways abutting or within Project Area or
subject property:
Abutting tracts, platted land, or built
developments:
��tJ���S� ,v lo lvsyz.. / 5 aQ0
Named Regulatory Watercourse(s) & Watershed(s):
CD(I , "1 CI` cc �c
Tributary Basin(s):
5 i 5 OW Tr) 4Jc iA
Plat Information For Pro or Subject Property (or Phase)
Preliminary Plat File #:
Final Plat File #: Date:
Status and VoI /Pg:
Name:
File #:
If two plats, second name:
Date:
Status:
Zoning Information For Project or Subject Property (or Phase)
\ Proposed? Case Code:
Zoning Type: xistin or
Case Date Status:
Proposed? Case Code:
Zoning Type: Existing or
Case Date Status:
Stormwater Management Planning For Pro or Subject Property (or Phase)
Planning Conference(s) & Date(s):
Participants:
Date Review Date
Preliminary Report Required? Submittal
No In Writing? When?
Review Comments Addressed? Yes
Compliance With Preliminary Drainage Report. Briefly describe (or attach documentation
explaining) any deviation(s) from provisions of Preliminary Drainage Report, if any.
k)IA
SECTION IX
STORMWATER DESIGN GUIDELINES
Effective February 2007
APPENDIX D — TECHNICAL DESIGN SUMMARY
Page 4 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
As Revised February 2009
SECTION IX
STORMWATER DESIGN GUIDELINES
Effective February 2007
APPENDIX D - TECHNICAL DESIGN SUMMARY
Page 5 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
As Revised February 2009
Part 2 — Project Administration
I Continued (page 2.3)
Coord For Pro or Sub Property (or Phase)
Note: For any Coordination of stormwater matters indicated below, attach documentation
describing and substantiating any agreements, understandings, contracts, or approvals.
Coordination
With Other
Departments of
Jurisdiction
City (Bryan or
College Station)
Dept.
Contact:
Date:
Subject:
Coordination With
Non - jurisdiction
City Needed?
Yes No '
Summarize need(s) & actions taken (include contacts & dates):
Coordination with
Brazos County
Needed?
Yes No k/
Summarize need(s) & actions taken (include contacts & dates):
Coordination with
TxDOT Needed? /
Yes No '/
Summarize need(s) & actions taken (include contacts & dates):
Coordination with
TAMUS Needed? /
Yes No ✓
Summarize need(s) & actions taken (include contacts & dates):
Permits
For Project or Subject Property (or Phase)
As to stormwater management, are permits required for the proposed work from any of the entities
listed below? If so, summarize status of efforts toward that objective in spaces below.
Entity
Permitted or
Approved ?
Status of Actions (include dates)
US Army Crops of
Engineers
No ✓ Yes
US Environmental
Protection Agency
No ✓ Yes
Texas Commission on
Environmental Quality
No ✓ Yes
Brazos River
Authority /
No ✓ Yes
SECTION IX
STORMWATER DESIGN GUIDELINES
Effective February 2007
APPENDIX D - TECHNICAL DESIGN SUMMARY
Page 5 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
As Revised February 2009
SECTION IX
APPENDIX D - TECHNICAL DESIGN SUMMARY
Part 3 — Property Characteristics
Start (Page 3.1)
Nature and Scope of Proposed Work
Existin : Land proposed for development currently used, including extent of impervious cover?
■
i 9 6 It ().eue(opi,4,,.1 i1 ;e ( SvA��v'.St' �1 :v 6
R' OG✓ - vIOdS CB - �S �r
Site
Development
Project
(select all
applicable)
Subdivision
Development
Project
Describe
Nature and
Size of
Proposed
Project
Encroachment(s)
into Floodplain
areas planned?
No
Yes
Redevelopment of one platted lot, or two or more adjoining platted lots.
Building on a single platted lot of undeveloped land.
Building on two or more platted adjoining lots of undeveloped land.
Building on a single lot, or adjoining lots, where proposed plat will not form
a new street (but may include ROW dedication to existing streets).
Other (explain):
Construction of streets and utilities to serve one or more platted lots.
Construction of streets and utilities to serve one or more proposed Tots on
lands represented by pending plats.
Site proiects: building use(s), approximate floor space, impervious cover ratio.
Subdivisions: number of lots by general type of use, linear feet of streets and
drainage easements or ROW.
Is any work planned on land that is not platted
or on land for which platting is not pending?
', No Yes
Is any part of subject property abutting a Named Regulatory Watercourse
(Section II, Paragraph B1) or a tributary thereof?
Is any part of subject property in floodplain I No Yes
If yes, explain:
FEMA Floodplains
No
Yes
tV Rate Map /e» di 'hy
r
area of a FEMA - regulated watercourse?
Encroachment purpose(s): Building site(s) Road crossing(s)
Utility crossing(s) Other (explain):
If floodplain areas not shown on Rate Maps, has work been done toward amending the FEMA-
approved Flood Study to define allowable encroachments in proposed areas? Explain.
STORMWATER DESIGN GUIDELINES Page 6 of 26 APPENDIX. D: TECH. D ESIGN February SUMMARY
Effective February 2007 As
ni C�-ec1-
J i.omR
SECTION IX
STORMWATER DESIGN GUIDELINES
Effective February 2007
APPENDIX D - TECHNICAL DESIGN SUMMARY
Page 7 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
As Revised February 2009
Part 3 — Property Characteristics
I Continued (Page 3.2)
Hydrologic Attributes of Subject Property
(or Phase)
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.
C gs - jq' - T u"I'k :-, , Sec-1 aeb
Is the stormwater
earlier study?
management plan for the property in substantial
Yes ✓ No If not, explain how
conformance with the
it differs.
No
If subject property
plan for the property
is not part of multi -phase project, describe
stormwater management
in Part 4.
If property is part of multi -phase project, provide overview of stormwater management plan
for Project Area here. In Part 4 describe how plan for subject property will comply
therewith.
Do existing
Describe
topographic features on subject property store or detain
them (include approximate size, volume, outfall, model, etc).
runoff? ✓ No Yes
Any known drainage or flooding problems in areas near subject property?
Identify:
-- Yes
Based on location of
(see Table B -1 in Appendix
Detention is required.
study property in a watershed, is Type 1 Detention (flood control) negded?
B) /reu 1 to r , ,/iA9,,, 'r / c I 4, s r ha s e.
Needst be evaluated. / Detention not required.
If the need for
Type 1 Detention
must be evaluated:
What decision has been reached? By whom?
How was determination made?
SECTION IX
STORMWATER DESIGN GUIDELINES
Effective February 2007
APPENDIX D - TECHNICAL DESIGN SUMMARY
Page 7 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
As Revised February 2009
SECTION IX
STORMWATER DESIGN GUIDELINES
Effective February 2007
APPENDIX D - TECHNICAL DESIGN SUMMARY
I Continued (Page 3.3)
Part 3 — Property Characteristics
Hydrologic Attributes of Subject Property (or Phase) (cornttnued)
Yes If yes,
Does subject property straddle a Watershed or Basin divide? No
describe splits below. In Part 4 describe design concept for handling this.
Watershed or Basin
Larger acreage
Lesser acreage
Above-Project (S f II Paragraph B3 a)
ve- Project reas ec ion ,
Does Project Area (project or phase) receive runoff from upland areas? N o Yes
Size(s) of area(s) in acres: 1) 2 ) 3 ) 4)
Flow Characteristics (each instance) (overland sheet, shallow concentrated, recognizable
concentrated section(s), small creek (non - regulatory), regulatory Watercourse or tributary);
Flow determination: Outline hydrologic methods and assumptions:
Does storm runoff drain from public easements or ROW onto or across subject property?
No Yes If yes, describe facilities in easement or ROW:
Are changes in runoff characteristics subject to change in future? Explain
Conveyance Pathways (Section 11, Paragraph C2)
Must runoff from study property drai across lower properties before reaching a Regulatory
Watercourse or tributary? No Yes
Describe length and characteristics of each conveyance pathway(s). Include ownership of
property(ies).
Page 8 of 26 APPENDIX. D: TECH. D ESIGN February SUMMARY
As
SECTION IX
STORMWATER DESIGN GUIDELINES
Effective February 2007
APPENDIX D — TECHNICAL DESIGN SUMMARY
Continued (Page 3.4)
Part 3 — Property Characteristics
Hydrologic Attributes of Subject Property (or Phase) (c ontinued) '
Conveyance Pathways (continued)
Do drainage
easements
exist for any
part of
pathway(s)?
No
Yes
Pathway
Areas
Nearby
Drainage
Facilities
If yes, for what part of length? % Created by?
instrument. If instrument(s), describe their provisions.
plat, or
Where runoff must cross lower properties, describe characteristics of abutting lower
property(ies). (Existing watercourses? Easement or Consent aquired ?)
Describe any built or improved drainage facilities existing near the property (culverts,
bridges, lined channels, buried conduit, swales, detention ponds, etc).
1 00.4 COn5)7 CcI G ,I Ibus .
Do any of these have hydrologic or hydraulic influence on proposed stormwater
design? No V Yes If yes, explain:
p r pore,d 5 Nr c�'irE�}ly
kg ^ /44 P Gfnr �)a.
PIi,N� �f•N.
Page 9 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
As Revised February 2009
SECTION IX
STORMWATER DESIGN GUIDELINES
Effective February 2007
APPENDIX D - TECHNICAL DESIGN SUMMARY
Part 4 — Drainage Concept and Design Parameters
Start (Page 4.1)
Stormwater Management Concept
Discharge(s) From Upland Area(s)
If runoff is to be received from upland areas, what design drainage features will be used to
accommodate it and insure it is not blocked by future development? Describe for each area,
flow section, or discharge point.
Discharge(s) To Lower Property(ies) (Section II, Paragraph E1)
Does project in Jude drainage features (existing or future) proposed to become public via
platting? No Yes Separate Instrument? No Yes
Per Guidelines reference above, how will
runoff be discharged to neighboring
property(ies)?
Establishing Easements (Scenario 1)
Pre - development Release (Scenario 2)
Combination of the two Scenarios
Scenario 1: If easements are proposed, describe where needed, and provide status of actions
on each. (Attached Exhibit # )
Scenario 2: Provide general description of how release(s) will be managed to pre - development
conditions (detention, sheet flow, partially concentrated, etc.). (Attached Exhibit # )
Combination: If combination is proposed, explain how discharge will differ from pre -
development conditions at the property line for each area (or point) of release.
If Scenario 2, or Combination are to be used, has proposed design been coordinated with
owner(s) of receiving property(ies)? No Yes Explain and provide
documentation.
Page 10 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
As Revised February 2009
SECTION IX
STORMWATER DESIGN GUIDELINES
Effective February 2007
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
Will project result
in shifting runoff
between Basins or
between
Watersheds?
No
Yes
How will runoff from Project
Area be mitigated to pre -
development conditions?
Select any or all of 1, 2,
and /or 3, and explain below.
Identify gaining Basins or Watersheds and acres shifting:
What design and mitigation is used to compensate for increased runoff
from gaining basin or watershed?
1.
2.
3.
With facility(ies) involving other development projects.
Establishing features to serve overall Project Area.
On phase (or site) project basis within Project Area.
1. Shared facility (type & Iocat'on of
Project Area): (Attached Exhibit #
facility; design drainage area served; relationship to size of
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)?
Are other Best Management Practices for reducing stormwater pollutants proposed?
No Yes Summarize type of BMP and extent of use:
If design of any runoff - handling facilities deviate from provisions of B -CS Technical
Specifications, check type facility(ies) and explain in later questions.
Detention elements Conduit elements Channel features
Swales Ditches Inlets Valley gutters Outfalls
Culvert features Bridges Other
Page 11 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
As Revised February 2009
SECTION IX
STORMWATER DESIGN GUIDELINES
Effective February 2007
APPENDIX D - TECHNICAL DESIGN SUMMARY
Part 4 — Drainage Concept and Design Parameters I Continued (Page 4.3)
Stormwater Management Concept (continued)
Within Project Area Of Multi -Phase Project (continued)
Will Project Area include bridge(s) or culvert(s)? V No
general size and In which phase(s).
Yes Identify type and
If detention /retention serves (will serve) overall Project Area, describe how it relates to subject
phase or site project (physical location, conveyance pathway(s), construction sequence):
���� W �k n v��ul o2ese /(
5 r)"/-v--- 6 ZIA S.
Within Or Serving Subject Property (Phase, or Site)
If property part of larger Project rea, is design in substantial conformance with earlier analysis
and report for larger area? Yes No, then summarize the difference(s):
Identify whether each of the types of drainage features listed below are included, extent of use,
and general characteristics.
Typical shape? Surfaces?
Steepest side slopes:
Usual front s opes: Usual back slopes:
Flow line slopes: least
typical greatest
Typica distance from travelway:
(Attached Exhibit # )
Are longitudinal culvert ends in compliance with B -CS Standard Specifications?
Yes No, then explain:
At in sections or otherwise, do valley gutters cross arterial or collector streets?
No Yes If yes explain:
Are )valley gutters proposed to cross any street away from an intersection?
sl No Yes Explain: (number of locations ?)
Page 12 of 26 APPENDIX. D: TECH.
As H. DESIGN uUSUMMARY
SECTION IX
STORMWATER DESIGN GUIDELINES
Effective February 2007
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 ba 7a Usual D 7 o Greatest D, 8o <-
,� No If "no ",
-0
a� N
te a)
}
co
c O
�Z
- 0
cn
E
0
Are inlets recessed on arterial and collector streets? Yes
identify where and why.
r [
t
r wl IQC 14tS
Will inlets capture 10 -year design stormflow to prevent flooding of intersections (arterial
with arterial � Off or collector) ? Yes No If no, explain where and why not. celtec
Will inlet size and placement prevent exceeding allowable water spread d f o r 10 -year
design storm throughout site (or phase)? explain.
Saq curves: Are inlets placed at low points? ✓ Yes No Are inlets and
condpit sized to prevent 100 -year stormflow from ponding at greater than 24 inches?
✓ Yes No Explain "no" answers.
Will 100 -yr stormflow be contained combination o ROW no, and buried
r be where u why.
whole length of all streets?
Do desi s for curb, gutter, If not, describe d fferencce() and attach Specifications?
Yes f cation.
Are any 12 -inch laterals used? /No Yes Identify length(s) and where
used.
Pipe runs between system Typical i Longest /77'
access points (feet):
Are junction boxes used at each bend? Yes No If not, explain where
and why.
Are doytream soffits at or below upstream soffits?
Yes No If not, explain where and why:
Least amount that hydraulic
grade line is below gutter line
(system - wide):
x,53'
Page 13 of 26 APPENDIX. D: TECH.
Revised DESIGN Feb uary 2009
As
Part 4 — Drainage Concept and Design Parameters
Continued (Page 4.5)
Stormwater Management Concept (continued)
Within Or Serving Subject Property (Phase, or Site) (continued)
a
m
c
N
L
0
E
0L-
o 0
E
U a
E E
to'
c-8
N o
ID d
E
o 2
a )
0. u)
0
g
7
O
Describe watercourse(s), or system(s) receiving system discharge(s) below
(include design discharge velocity, and angle between converging flow lines).
1) Watercourse (or system), velocity, and angle?
ap (od ; ('a -P/ , �� 6 o
2) Watercourse (or system), velocity, and angle?
i'ir a7° ' Sal �s ; 9� 7 o.
3) Watercourse (or system), velocity, and angle?
For each outfall above, what measures are taken to prevent erosion or scour of
receiving and all facilities at juncture?
1 ) b ,41 J wi i i b, L ), A des S-1 „ , J (I•
2 6 ,1 - t1' (;,i1 y< � 5 d ,) J, ( t�s
3)
c-
ca
a)
Are situated along property lines between properties? No Yes
swale(s)
Number of instances: For each instance answer the following questions.
Surface treatments (including low -flow flumes if any):
m 0
) }
E
a
0
Flow line slopes (minimum and maximum):
2 Z
(1)
a�
a)
Ws
2
<
Outfall characteristics for each (velocity, convergent angle, & end treatment).
Will 100 -year design storm runoff be contained within easement(s) or platted drainage
ROW in all instances? Yes No If "no” explain:
SECTION IX
STORMWATER DESIGN GUIDELINES
Effective February 2007
APPENDIX D — TECHNICAL DESIGN SUMMARY
Page 14 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
As Revised February 2009
SECTION IX
STORMWATER DESIGN GUIDELINES
Effective February 2007
APPENDIX D — TECHNICAL DESIGN SUMMARY
Part 4 — Drainage Concept and Design Parameters
Continued (Page 4.6)
Storrnwater Management Concept (continued)
Within Or Serving Subject Property (Phase; or Site) (continued)
Are roadside ditches used? " No Yes If so, provide the following:
Is 25 -year flow contained with 6 inches of freeboard throughout ? Yes No
Are top of banks separated from road shoulders 2 feet or more? Yes No
Are all ditch sections trapezoidal and at least 1.5 feet deep? Yes No
a)
a)
0
o
m
0
m CO
c >,
C
CO as
t
U "
C
O
CD c
o
CO
o E
c
• 0
• c
• a)
E • va
m
(1)
• a)
C
o >
- o
c °-
m
E
o L
• N
0
c n
0 N
a) c
f6 0
v7
For any "no" answers provide location(s) and explain:
If conduit is beneath a swale, provide the following information (each instance).
Instance 1 Describe general location, approximate length:
Is 100 -year design flow contained in conduit/swale combination? Yes No
If "no" explain:
Easement Width
Space for 100 -year storm flow? ROW
Conduit Type and size, minimum and maximum
slopes, design storm:
Swale Surface type, minimum
and maximum slopes:
Inlets Describe how conduit is loaded (from streets /storm drains, inlets by type):
Access Describe how maintenance access is provided (to swale, into conduit):
Instance 2 Describe general location, approximate length:
Is 100 -year design flow contained in conduit/swale combination? Yes No
If "no" explain:
Space for 100 -year storm flow? ROW Easement Width
Swale Surface type, minimum Conduit Type and size, minimum and maximum
and maximum slopes: slopes, design storm:
Inlets Describe how conduit is loaded (from streets /storm drains, inlets by type):
Access Describe how maintenance access is provided (to swale, into conduit):
Page 15 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
As Revised February 2009
Part 4 — Drainage Concept and Design Parameters
Continued (Page 4.7)
Stormwater Management Concept (continued)
Within Or Serving Subject Property (Phase, or Site) (continued)
If "yes" provide the following information for each instance:
c
0
a
E w
vi
>_
Instance 1 Describe general location, approximate length, surfacing:
Is 100 design flow contained in swale? Yes No Is swale wholly
-year
within drainage ROW? Yes No Explain "no" answers:
s
a)
0
Access Describe how maintenance access is provide:
m
o
S z
5 , J
0
0
v
a)
•c cam•
c
m
o E
3 c
m a)
— o
co O
_ 1
U_
7
a
Instance 2 Describe general location, approximate length, surfacing:
Is 100 design flow contained in swale? Yes No Is swale wholly
-year
within drainage ROW? Yes No Explain "no" answers:
Access Describe how maintenance access is provided:
Instance 3, 4, etc. If swales are used in more than two instances, attach sheet
providing all above information for each instance.
I c
"New" channels: Will any area(s) of concentrated flow be channelized (deepened,
straightened) or otherwise altered? No Yes If only slightly
widened, or
shaped, see "Swales" in this Part. If creating side banks, provide information below.
Will design replicate natural channel? Yes No If "no ", for each instance
m
o w
a
co m
c }
a>
E
a)
o
2
0
m
0
c
m
L
0
shape section sha e & area, flow line slope (min. & max.), surfaces, and 100 -year
design flow, and amount of freeboard:
Instance 1:
Instance 2:
Instance 3:
SECTION IX
STORMWATER DESIGN GUIDELINES
Effective February 2007
APPENDIX D - TECHNICAL DESIGN SUMMARY
Page 16 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
As Revised February 2009
SECTION IX
STORMWATER DESIGN GUIDELINES
Effective February 2007
APPENDIX D - TECHNICAL DESIGN SUMMARY
Part 4 — Drainage Concept and Design Parameters
I Continued (Page 4.8)
Stormwater Management Conc (continued)
Within Or Serving Subject Property (Phase, or Site) (continued)
Existing channels (small creeks): Are these used? No
If "yes" provide the information below.
Will small creeks and their floodplains remain und stun e d location:
No How
many disturbance instances? y planned
Yes
For each location, describe length and general type of proposed improvement
(including floodplain changes):
For each location, describe section shape & area, flow line slope (min. & max.),
surfaces, and 100 -year design flow.
Watercourses (and tributaries): Aside from fringe changes, are Regulatory
Watercourses proposed to be altered? No Yes Explain below.
Submit full report describing proposed changes to Regulatory Watercourses. Address
existing and proposed section size and shape, surfaces, alignment, flow line changes,
length affected, and capacity, and provide full documentation of analysis procedures
and data. Is full report submitted? Yes No If "no" explain:
All Proposed Channel Work: For all proposed channel work, provide information
requested in next three boxes.
If design is to replicate natural channel, identify location and length here, and describe
design in Special Design section of this Part of Report.
Will 100 -year flow be contained with one foot of freeboard? Yes No If
not, identify location and explain:
Are ROW / easements sized to contain channel and required maintenance space?
Yes No If not, identify location(s) and explain:
Page 17 of 26 APPENDIX. D: As Revised DESIGN February 2009Y
SECTION IX
STORMWATER DESIGN GUIDELINES
Effective February 2007
APPENDIX D - TECHNICAL DESIGN SUMMARY
Part 4 — Drainage Concept and Design Parameters Continued (Page 4.9)
Stormwater Management Concept (continued)
Within Or Serving Subject Property (Phase, or Site) (continued)
a)
0
a)
u_
a)
How many facilities for subject property project?
For each provide info. below.
For each dry-type facilitiy:
Acres served & design volume + 10%
100 -yr volume: free flow & plugged
Design discharge (10 yr & 25 yr)
Spillway crest at 100 -yr WSE?
Berms 6 inches above plugged WSE?
Facility 1
yes no
yes no
Facility 2
For each facility what is 25 -yr design Q, and design of outlet structure?
Facility 1:
Facility 2:
Do outlets and spillways discharge into a public facility in easement or ROW?
Facility 1: Yes No Facility 2: Yes No
If "no" explain:
yes no
yes no
Explain any "no" answers:
For each, what is velocity of 25 -yr design discharge at outlet? & at spillway?
Facility 1: & Facility 2:
Are energy dissipation measures used? No Yes Describe type and
location:
For each, is spillway surface treatment other than concrete? Yes or no, and describe:
Facility 1:
Facility 2:
For each, what measures are taken to prevent erosion or scour at receiving facility?
Facility 1:
Facility 2:
If berms are used give heights, slopes and surface treatments of sides.
Facility 1:
Facility 2:
Page 18 of 26 APPENDIX. D: ECH. DESIGN uUSUMMARY
SECTION IX
STORMWATER DESIGN GUIDELINES
Effective February 2007
APPENDIX D - TECHNICAL DESIGN SUMMARY
Part 4 — Drainage Concept and Design Parameters I Continued (Page 4.10)
Stormwater Management Concept (continued)
Within Or Serving Subject Property (Phase, or Site) (continued)
Do structures comply with B -CS Specifications? Yes or no, and explain if "no ":
Facility 1;
a)
U - 0
as N
u-
c
• jy
o 0
• o
G)
a)
0
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Facility 2:
For additional facilities provide all same information on a separate sheet.
Are parking areas to be used for detention? No Yes What is
maximum depth due to required design storm?
Roadside Ditches: Will culverts serve access driveways at roadside ditches?
No Yes If "yes ", provide information in next two boxes.
Will 25 -yr. flow pass without flowing over driveway in all cases? Yes No
Without causing flowing or standing water on public roadway? Yes No
Designs & materials comply with B -CS Technical Specifications? Yes No
Explain any "no" answers:
Are culverts parallel to public roadway alignment? Yes No Explain:
Creeks at Private Drives: Do private driveways, drives, or streets cross drainage
ways that serve Above - Project areas or are in public easements/ ROW?
No Yes If "yes" provide information below.
How many instances? Describe location and provide information below.
Location 1:
Location 2:
Location 3:
For each location enter value for:
Design year passing without toping travelway?
Water depth on travelway at 25 -year flow?
1
2
Water depth on travelway at 100 -year flow?
For more instances describe location and same information on separate sheet.
3
Page 19 of 26 APPENDIX. D: A CH. D ESIGN u SUMMARY
SECTION IX
STORMWATER DESIGN GUIDELINES
Effective February 2007
APPENDIX D — TECHNICAL DESIGN SUMMARY
Part 4 — Drainage Concept and Design Parameters
I 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? 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:
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Arterial or Maior Collector Streets: Will culverts serve these types of roadways?
No Yes How many instances? For each identify the
location and provide the information below.
Instance 1:
Instance 2:
Instance 3:
Yes or No for the 100 -year design flow:
Headwater WSE 1 foot below lowest curb top?
Spread of headwater within ROW or easement?
Is velocity limited per conditions (Table C -11)?
For each instance enter value, or "yes" / "no" for:
Design yr. headwater WSE 1 ft. below curb top?
100 -yr. max. depth at street crown 2 feet or less?
Product of velocity (fps) & depth at crown (ft) _ ?
Is velocity limited per conditions (Table C -11)?
Limit of down stream analysis (feet)?
1
Explain any "no" answer(s):
Minor Collector or Local Streets: Will culverts serve these types of streets?
No Yes How many instances? for each identify the
location and provide the information below:
Instance 1:
Instance 2:
Instance 3:
1
2
2
3
3
Explain any "no" answers:
Page 20 of 26 APPENDIX. D: ECH. DESIGN uUSUMMARY
SECTION IX
STORMWATER DESIGN GUIDELINES
Effective February 2007
APPENDIX D - TECHNICAL DESIGN SUMMARY
Part 4 — Drainage Concept and Design Parameters
Continued (Page 4.12)
Stormwater Management Concept (continued)
Within Or Serving Subject Property (Phase, or Site) (continued)
All Proposed Culverts: For all proposed culvert facilities (except driveway /roadside
ditch intersects) provide information requested in next eight boxes.
Do culverts and travelways intersect at 90 degrees? Yes No If not,
identify location(s) and intersect angle(s), and justify the design(s):
Does drainage way alignment change within or near limits of culvert and surfaced
approaches thereto? No Yes If "yes" identify Iocation(s), describe
change(s), and justification:
Are flumes or conduit to discharge into culvert barrel(s)? No Yes If yes,
identify Iocation(s) and provide justification:
Are flumes or conduit to discharge into or near surfaced approaches to culvert ends?
No Yes If "yes" identify Iocation(s), describe outfall design treatment(s):
Is scour /erosion protection provided to ensure long term stability of culvert structural
components, and surfacing at culvert ends? Yes No If "no" Identify
locations and provide justification(s):
Will 100 -yr flow and spread of backwater be fully contained in street ROW, and /or
drainage easements/ ROW? Yes No if not, why not?
Do appreciable hydraulic effects of any culvert extend downstream or upstream to
neighboring land(s) not encompassed in subject property? No Yes If
"yes" describe location(s) and mitigation measures:
Are all culvert designs and materials in compliance with B -CS Tech. Specifications?
Yes No If not, explain in Special Design Section of this Part.
Page 21 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
As Revised February 2009
SECTION IX
STORMWATER DESIGN GUIDELINES
Effective February 2007
APPENDIX D - TECHNICAL DESIGN SUMMARY
Part 4 — Drainage Concept and Design Parameters
I Continued (Page 4.13)
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
If "yes" provide the following information.
Name(s) and functional classification of the roadway(s)?
What drainage way(s) is to be crossed?
A full report supporting all aspects of the proposed bridge(s) (structural, geotechnical,
hydrologic, and hydraulic factors) must accompany this summary report. Is the report
provided? Yes No If "no" explain:
Is a Stormwater
Pollution Prevention
Plan (SW3P)
established for
project construction?
No Yes
Provide a general description of planned techniques:
Special Designs — Non - Traditional Methods
Are any non - traditional methods (aquatic echosystems, wetland -type detention, natural stream
replication, BMPs for water quality, etc.) proposed for any aspect of subject property project?
No Yes If "yes" list general type and location below.
N�A
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:
Page 22 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
As Revised February 2009
Part 4 — Drainage Concept and Design Parameters
Continued (Page 4.14)
Stormwater Management Concept (continued)
Within Or Serving Subject Property (Phase, or Site) (continued)
Special Designs — Deviation From B -CS Technical Specifications
If any design(s) or material(s) of traditional runoff - handling facilities
B -CS Technical Specifications, check type facility(ies) and explain by
Detention elements Drain system elements
deviate from provisions of
specific detail element.
Channel features
Inlets Outfalls
Culvert features Swales Ditches
Valley gutters Bridges (explain in bridge report)
In table below briefly identify specific element, justification for deviation(s).
Specific Detail Element
Justification for Deviation (attach additional sheets if needed)
1)
2)
3)
4)
5)
Have elements been coordinated with the City Engineer or her /his designee? For each item
above provide "yes" or "no ", action date, and staff name:
1)
2)
3)
4)
5)
Design Parameters
Hydrology
Is a map(s) showing all Design Drainage Areas provided? i/ Yes No
Briefly summarize the range of applications made of the Rational Formula:
What is the size and location of largest
has been applied? 5 1, 7' acres
Design Drainage Area to which the Rational Formula
Location (or identifier): Tv, 3 0
•
SECTION IX
STORMWATER DESIGN GUIDELINES Page 23 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
As Revised February 2009
Effective February 2007
APPENDIX D - TECHNICAL DESIGN SUMMARY
•
SECTION IX
STORMWATER DESIGN GUIDELINES
Effective February 2007
APPENDIX D - TECHNICAL DESIGN SUMMARY
Page 24 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
As Revised February 2009
Part 4 — Drainage Concept and Design Parameters
I Continued (Page 4.15)
Design Parameters (continued)
Hydrology (continued)
In making detep'ninations for time of concentration, was segment analysis used?
of Design Drainage Areas? ( %
No V Yes In approximately what percent
As to intensity- duration - frequency and rain depth criteria for deter runoff flows, were any
in these Guidelines used? V No Yes If "yes"
criteria other than those provided
identify type of data, source(s), and where applied:
For each of the stormwater management features listed below identify the storm return
frequencies (year) analyzed (or checked), and that used as the basis for design.
Feature
Analysis Year(s)
Design Year
Storm drain system for arterial and collector streets
Storm drain system for local streets
(vc ,�
to 'IT
Open channels
Swale /buried conduit combination in lieu of channel
Swales
Roadside ditches and culverts serving them
Detention facilities: spillway crest and its outfall
Detention facilities: outlet and conveyance structure(s)
Detention facilities: volume when outlet plugged
Culverts serving private drives or streets
Culverts serving public roadways
Bridges: provide in bridge report.
Hydraulics
What is the range of design flow velocities as outlined below?
Design flow velocities;
Gutters
Conduit
Culverts
Swales
Channels
Highest (feet per second)
1, C
, , Q1
Lowest (feet per second)
a , o
1, ‘,c
Streets and Storm Drain Systems Provide the summary information outlined below:
used: For street gutters: . 01 D a i 3
Roughness coefficients
iLt - ip 4 PC Coefficients: -CJ- o. ° ( a
For conduit type(s)
•
SECTION IX
STORMWATER DESIGN GUIDELINES
Effective February 2007
APPENDIX D - TECHNICAL DESIGN SUMMARY
Page 24 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
As Revised February 2009
Part 4 — Drainage Concept and Design Parameters
Continued (Page 4.16)
Design Parameters (continued)
Hydraulics (continued)
Street and Storm Drain Systems (continued)
For the following, are as mptions other than allowable per Guidelines?
Inlet coefficients? t_No Yes Head and friction losses No Yes
Explain any "yes" answer:
In conduit is velocity generally increased in the downstream direction?
Are elevation drops provided at inlets, manholes, and junction boxes?
Explain any "no" answers:
✓// Yes No
'/ Yes No
Are hydraulic grade lines calculated shown for design storm? / Yes No
For 100 -year flow conditions? t/ 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:
y r s /-4 '5-7''''' r sys was J' s -se / ic i -> ,,,t/
fn. D,/,-)- �t ._ ele � r bP 46 -Li .
Open Channels If a HEC analysis is utilized, does it follow Sec VI.F.5.a?
Yes No
Outside of straight sections, is flow regime within limits of sub - critical
If "no" list locations and explain:
N A
flow? Yes No
Culverts If plan sheets do not provide the following for each culvert, describe it here.
For each design discharge, will operation be outlet (barrel) control or inlet control?
Mk
Entrance, friction and exit losses:
Bridges Provide all in bridge report
SECTION IX
APPENDIX D - TECHNICAL DESIGN SUMMARY
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
STORMWATER DESIGN GUIDELINES
Effective February 2007
Page 26 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
As Revised February 2009
Part 4 — Drainage Concept and Design Parameters
Continued (Page 4.17)
Design Parameters (continued)
Computer Software
What computer software has been used in the analysis and assessment of stormwater
management needs and /or the development of facility designs proposed for subject property
project? List them below, being sure to identify the software name and version, the date of the
version, any applicable patches and the publisher
K `^ .` Dr 4,7ti,cacl (iv, I 3!)
c,-0Sa eX6eI aO'
Part 5 — Plans and Specifications
Requirements for submittal of construction drawings and specifications do not differ due to use of a
Technical Design Summary Report. See Section III, Paragraph C3.
Part 6 — Conclusions and Attestation
Conclusions
Add any concluding information here:
Attestation
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
by me (or under my supervision) in accordance with provisions of the
Unified Drainage Design Guidelines for the owners of the property.
required by any and all state and federal regulatory agencie '
improvemen s have been issued or fall under applicable gen: - Al"
(Affi al)
KENT
in Part B was prepared
Bryan /College Station
All licenses and permits
'i - • . •osed drainage
, %..4.�
N ' •
M. LAZ ���
8592.9 ��
L - 3 , - ''
•.Y
Licensed Professional En sneer .. I.
2
State of Texas PE No. 6 3 / 3 h
ti
•
SECTION IX
APPENDIX D — TECHNICAL DESIGN SUMMARY
STORMWATER DESIGN GUIDELINES
Effective February 2007
Page 26 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
As Revised February 2009