HomeMy WebLinkAbout09-00100066- 00076443Drainage Report
for
Castle Rock Subdivision
Phase 4
College Station, Texas
November, 2009
r
Engineer:
HARLE ENGINEERING COMPANY
P.O. Box 11587
College Station, TX 77842
3002 Texas Avenue South
College Station, Texas 77845
(979) 693 -7191
Developer.
Greens Prairie Investors, Ltd.
4490 Castlegate Drive
College Station, Texas 77845
(979) 690 -7250
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SECTION IX
APPENDIX D - TECHNICAL DESIGN SUMMARY
Part 4 — Drainage Concept and Design Parameters
Continued (Page 4.15)
es�IgPart�me�� {CQit�rutl) �.
J • � n � .s!+k�'�`.S. ; d�f Clt ;5;`�' +4•,Ain 4.N�e
Hydrology (continued)
In making detemlinations for time of concentration, was segment analysis used?
No ✓ Yes In approximately what percent of Design Drainage Areas?
As to intensity - duration- frequency and rain depth criteria for determ ing runoff flows, were any
criteria other than those provided in these Guidelines used? I/No Yes If "yes`
identify type of data, source(s), and where applied:
For each of the stormwater management features listed below identify the storm return
frequencies (year) analyzed (or checked), and that used as the basis for design.
Feature
Analysis Year(s)
Design Year
Storm drain system for arterial and collector streets
N /(�-
N //4
Storm drain system for local streets
10 I
tf o
Open channels
N
N/A
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)
I r
Detention facilities: volume when outlet plugged
Culverts serving private drives or streets
"
Culverts serving public roadways
�
Bridges: provide in bridge report.
t
Hydraulics
What is the range of design flow velocities
as outlined below?
Design flow velocities;
Gutters
Conduit
Culverts
Swales
Channels
Highest (feet per second)
q.
--
Lowest (feet per second)
3,
Streets and Storm Drain Systems Provide the summary information outlined below:
Roughness coefficients used: For street gutters: 0 - 0 1 b
For conduit type(s) H IO'pIS g c- Coefficients: 0•Lt 1 Z 0. 013
STORMWATER DESIGN GUIDELINES Page 24 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
Effective February 2007 As Revised February 2009
Rev. 11 01
Drainage Report
for
Castle Rock Subdivision
Phase 4
College Station, Texas
November, 2009
Engineer.
HARLE ENGINEERING COMPANY
P.O. Box 11587
College Station, TX 77842
3002 Texas Avenue South
College Station, Texas 77845
(979) 693 -7191
Developer.
Greens Prairie Investors, Ltd.
4490 Castlegate Drive
College Station, Texas 77845
(979) 690 -7250
Castle Rock Subdivision, Phase 4
Drainage Report — Executive Summary
ENGINEER
HARLE ENGINEERING COMPANY
P.O. Box 11587
College Station, Texas 77842
Phone/Fax: (979) 693 -7191
OWNER/DEVELOPER
Greens Prairie Investors, LLC
4490 Castlegate Drive
College Station, Texas 77845
Phone: (979) 690 -7250
GENERAL DESCRIPTION AND LOCATION
Castle Rock Subdivision, Phase 4, is located on the north side of SH 40, William
Location:
D. Fitch Parkway, near its intersection with Castle Rock Parkway.
Description:
■ Area:
■ Proposed Land Use:
5.601 acres
PDD- Single Family Residential
�. ■ # of Lots:
■Existing Land Use:
26 lots
Agricultural — consisting primarily of a wooded pasture used for cattle grazing
The is heavily wooded.
■Land Description:
Rolling terrain that falls north toward Spring Creek. site
site and y developed sections of the Castle
Adjoining Land Use:
Rock ubdi on the north by Castle Rock Park and a greenbelt and on the
east by future sections of Castle Rock.
Primary Drainage Facility:
Spring Creek
Flood Hazard Information:
FEMA FIRM
# 48041CO205 D (February 9, 2000)
this Phase lies within the fl oodplain of Spring Creek or its
Floodplain:
No portion of
tributaries.
M
HYDROLOGIC CHARACTERISTICS
The existing site is predominately wooded. The elevations range from 275 to 285, sloping generally in a
northeasterly direction where the runoff enters tributaries of Spring Creek, which ultimately flow into
Spring Creek on the adjacent tracts.
GENERAL STORMWATER PLAN
.. The drainage plan for this development will involve the installation of inlets, junction boxes and storm
sewer pipes for 2 separate systems which both will discharge into an existing ditch which is located in the
future Phase 6 area of Castle Rock. This ditch is a tributary of Spring Creek. One of the systems connects
to an existing storm sewer pipe which was constructed with Phase 2B which collects the runoff from
existing storm sewer systems constructed with Phases IA, 2A, 2B and 3. The detention pond for this
proposed development is located downstream of this development, on Spring Creek, adjacent to SH 6, on
the Crowley Tract, which is being developed as the Tower Pointe development.
Page 1 of 3
COORDINATION & STORMWATER PERMITTING
The project will require that a Notice of Intent be submitted to the Texas Commission for Environmental
Quality. No other permits are anticipated for this project.
DRAINAGE DESIGN
General Information: Stormwater runoff from Phase 4 of the subdivision will be collected by 2 separate
systems which discharge into an existing ditch. One system primarily carries the
runoff from previous Phases and the other collects runoff from Phase 4 and the
Castle Rock Park area adjacent to the site. The location of the drainage areas for
evaluation of the gutter depth check, inlet sizing and pipe evaluation are shown on
Exhibit A. Also shown are the location of the inlets, junction boxes and storm
sewer pipes.
In order to not have to construct open channels for the storm sewer pipes in Phase
4 to drain into and then fill these channels with the future development of Phases 5
and 6, storm sewer inlets, junction boxes and pipes are proposed with this Phase
even though they are located in Phase 5 and Phase 6.
Street Design: Standard cross - section (3% cross - slope, 27' B -B residential)
Lay down curb & gutter on residential streets
Asphalt pavement
Standard recessed curb inlets (5' length)
T. Methodology: TR 55
T, Minimum 10 minutes
Design Storm Event: 10 -year - residential street & storm sewer
Pipe Materials: Corrugated HDPE w /smooth interior, RCP, Profile Gasket in
accordance with ASTM C443, ASTM C78, Class III
Manning's n Value: 0.013
Runoff Coefficients: 0.60 for developed lots
Design Constraints: Max. water depth in curb = 4.0 in. or 0.33 ft.
Min. flow velocity = 2.5 fps
Max. flow velocity = 15 fps
100 -yr storm runoff maintained within the ROW (4 inches above curb)
Design Software: Excel spreadsheets, DODSON HydraCalc Hydraulics
This software was used to compute pipe capacity, flowrate and velocity through
each pipe, and determine hydraulic grade line elevations at each inlet or junction
box. All of this information is shown in the summary tables in Appendix E.
The College Station requirement for a 25% reduction in cross - sectional area of
pipes less than 27" diameter is achieved by using internal pipe diameters that are
less than the standard diameter. The 24" diameter pipe areas were reduced by 25%
and a 20.6" diameter pipe used in the analysis and the 18' diameter pipe areas were
reduced by 25% and a 15.6" diameter pipe was in the analysis.
Page 2 of 3
Design Results The data presented in the Appendices indicates the gutter depth, inlet sizing and
pipe sizes are in accordance with the requirements of the design guidelines.
Applicable Exhibits: Exhibit A — Drainage Area Map
Appendix A — Technical Design Summary
Appendix B — Drainage Area Calculations
Appendix C — Depth of Flow in Gutter Summary
Appendix D — Inlet Design Summary
Appendix E - Pipe Design Summary
DETENTION DESIGN
General: Stormwater runoff from Phase 4 and all previous and subsequent phases of the
Castle Rock Subdivision flow into Spring Creek upstream of the regional detention
facility constructed in 2001. This facility was designed to control stormwater
releases from the Castle Rock Subdivision and other adjoining properties. No
additional detention facilities are provided with the development of this project.
CONCLUSION Based on the concurrence with the previous design calculations from Phases IA,
2A, 2B and 3, the drainage system in Phase 4 of the Castlerock Subdivision will
function within the requirements and restrictions of the College Station Drainage
Policy and Design Standards.
CERTIFICATION
I, Joseph P. Schultz, Licensed Professional Engineer No. 65889, State of Texas, certify that this report for the
drainage design for Castle Rock Subdivision, Phase 4 , was prepared by me in accordance with the provisions
of the Unified Stormwater Design Guidelines.
A 4 '' -
Jos �P. ch ultz, P.E.
1 -3 -05
- 4s38
Page 3 of 3
APPENDIX A
Technical Design Summary
STORMWATER DESIGN GUIDELINES Page 3 of 26 APPENDIX. D: SIGN 2009
b uary
Effective February 2007
SECTION IX
APPENDIX D - TECHNICAL DESIGN SUMMARY
SECTION IX
APPENDIX D — TECHNICAL DESIGN SUMMARY
Part 2 — Project Administrat Continued (page 2.2)
Project Identification (continued)
Roadways abutting or within Project Area or A butting
evelopments:, platted land, or built
subject property: r (�.✓�cw" Z A
Named Regulatory Watercourse(s) & Watershed(s): Tributary Basin(s): L
'Plat Information for Project or Subject Property (or Phase)
Preliminary Plat File #: S
9 5" omo ' - Final Plat File #: Date: —
Name:
CGS +� e �` SYi�cl: v�S: Status and Vol /Pg: 5 4 ) I t - `t ° 9
If two plats, second name:
File #:
Date:
Status:
p or Phase
Zoning Information For Project or Subject Pro erty ( ) T.
Zoning Type: P Existin r Proposed? Case Code:
Case Date Status:
Zoning Type: Existing or Proposed? Case Code:
Case Date Status:
Stormwater Management Planning For Project or Subject Property (or Phase)
Planning Conference(s) & Date(s): Participants:
���� Review Date
Preliminary Report Required? rte! Submittal Date
m �
Review Comments Addressed? Yes IN�No In Writing? When?
Compliance With Preliminary Drainage Report. Briefly describe (or attach documentation
explaining) any deviation(s) from provisions of Preliminary Drainage Report, if any.
N
STORMWATER DESIGN GUIDELINES Page 4 of 26 APPENDIX. D: ECH. Ded uary SUMM
Effective February 2007
DESIGN
STORMWATER DESIGN GUIDELINES Page 5 of 26 APPENDIX. D: As C Reviised Eg u 200
ary 9
Effective February 2007
SECTION IX
APPENDIX D - TECHNICAL DESIGN SUMMARY
SECTION IX
APPENDIX D — TECHNICAL DESIGN SUMMARY
Part_ 3 Property Characteristics
I St art (Page 3.1)
Nature and Scope of Proposed Work
Existin : Land proposed for development currently used, including extent of impervious cover?
(1 one , Vice#.F'
Is any work planned on land that is not platted If yes, explain:
or on la for which platting is not pending /
No Yes
FEMA Floodplains
Is any part of subject property abutting a Named Regulatory Watercourse No ✓ Yes
(Section II, Paragraph B1) or a tributary thereof? ����� b Zo5
Is any part of subject property in floodplain No (/ Yes Rate Map
area of a FEMA - regulated watercourse?
Encroachment(s) Road crossings)
Encroachment purpose(s): Building site(s)
into Floodplain Other (explain):
areas planned? Utility crossing (s)/�
No V J�� 1'f
Yes
If floodplain areas not shown on Rate Maps, has work been .done toward amending the FEMA-
fine allowable encroachments in proposed areas? Explain.
approved Flood Study to de
STORMWATER DESIGN GUIDELINES Page 6 of 26 APPENDIX. D: TECH DES
vi ed Feb uary 2009
Effective February 2007
Redevelopment of one Ip atted lot, or two or more adjoining lap tted lots.
Site
Development
Building on a single lap tted lot of undeveloped land.
Project
Building on two or more Ip atted adjoining lots of undeveloped land.
(select all
Building on a single lot, or adjoining lots, where proposed plat will not form
ROW dedication to existing streets).
applicable)
a new street (but may include
Ni A-
Other (explain):
Construction of streets and utilities to serve one or more Ip atted lots.
Subdivision
Development
Construction of streets and utilities to serve one or more proposed lots on
Project
lands represented by ❑ending plats
Site Proiects building use(s), approximate floor space, impervious cover ratio.
type of use, linear feet of streets and
Subdivisions number of lots by general
Describe
Nature and
drainage easements or ROW. l
S� S - 3
Size of
'Z L S' t t i
Proposed
Project
Is any work planned on land that is not platted If yes, explain:
or on la for which platting is not pending /
No Yes
FEMA Floodplains
Is any part of subject property abutting a Named Regulatory Watercourse No ✓ Yes
(Section II, Paragraph B1) or a tributary thereof? ����� b Zo5
Is any part of subject property in floodplain No (/ Yes Rate Map
area of a FEMA - regulated watercourse?
Encroachment(s) Road crossings)
Encroachment purpose(s): Building site(s)
into Floodplain Other (explain):
areas planned? Utility crossing (s)/�
No V J�� 1'f
Yes
If floodplain areas not shown on Rate Maps, has work been .done toward amending the FEMA-
fine allowable encroachments in proposed areas? Explain.
approved Flood Study to de
STORMWATER DESIGN GUIDELINES Page 6 of 26 APPENDIX. D: TECH DES
vi ed Feb uary 2009
Effective February 2007
STORMWATER DESIGN GUIDELINES Page 7 of 26 APPENDIX. D TECH. DESIGN
Revised uary 200
Effective February 2007
SECTION IX
APPENDIX D - TECHNICAL DESIGN SUMMARY
SECTION IX
APPENDIX D — TECHNICAL DESIGN SUMMARY
+_ 3 - Pro na I C ontinued (Page 3.3)
Part Characteristics
Hydrologic Attributes of Subject Property (or P se) `(continued) '
'
Does subject property straddle a Watershed or Basin divide.
, � No Yes If yes,
describe splits below. In Part 4 describ design con ce t f La ge Il acr h age , Lesser a creage
Watershed or Basin
Above- Project Areas(Section II, Paragraph B3 -a)
Does Project Area (project or phase) receive runoff from upland areas? No Yes
Size(s) of area 2 s) in acres: 1) ) 3 ) — 4)
Fl Characteristics (each ins tance (overland sheet, shallow concentrated, recognizable
concentrated section(s), small creek (non - regulatory), regulatory Watercourse Qr tributary);
Flow determination: Outline hydrologic methods and assumptions: ! _
�l ft St < <'� prcv:out PAC) T°
r�u� I
" r- V\ N 0 T
Does s orm runoff drain from public easements or ROW onto or across subject property?
_ V No Yes If yes, describe facilities in easement or ROW:
Are changes in runoff characteristics subject to change in future? Explain
N o
M?! ways (Section II, Paragraph C2)
rom study property drain across lower P Yes ies before reaching a Regulatory
or tributary? No
gth and characteristics of each conveyance pathway(s). Include ownership of
. ^ < d we S C f- ��;S�T� rM�rot �J`� /
Page 8 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
STORMWATER DESIGN GUIDELINES 9 As Revised February 2009
Effective February 2007
STORMWATER DESIGN GUIDELINES Page 9 of 26 APPENDIX. D: As CH. DedI SUMMAR AR
Effective February 2007
SECTION IX
APPENDIX D - TECHNICAL DESIGN SUMMARY
SECTION IX
APPENDIX D - TECHNICAL DESIGN SUMMARY
Par 4 Drainaae Concept and Des 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. ++ S
Discharge(s) To Lower Property(ies) (Section Il, Paragraph E1)
Does project incl a drainage features (existing or future) proposed to become public via Yes
platting? No Yes Separate Instrument? No
Per Guidelines reference above, how will Establishing Easements (Scenario 1)
runoff be discharged to neighboring Pre - development Release (Scenario 2)
property(ies)? Combination of the two Scenarios
Scen_ ario 1: If easements are proposed, describe where needed, and provide status of actions
on each. (Attached Exhibit
Scenario 2: Provide general description of how release(s) will be managed to pre - development
conditions (detention, sheet flow, partially concentrated, etc.). (Attached Exhibit #
Combination: If combination is proposed, explain how discharge will differ from pre -
development conditions at the property line for each area (or point) of release.
If Scenario 2 , or Combination are to be used, has proposed design been coordinated with
owner(s) of receiving property(ies)? No
Yes Explain and provide
documentation.
STORMWATER DESIGN GUIDELINES Page 10 of 26 APPENDIX. D: As Revised EOLUary 2009
Effective February 2007
SECTION IX
APPENDIX D - TECHNICAL DESIGN SUMMARY
Part 4 Drainage Concept and Design Param eters I Continued (Page 4.2)
Stormwater Management Concept (continued)
Within Proiect 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
WanN ds? from gaining basin or watershed?
o
Yes
How will runoff from Project 1. ✓ With facility(ies) involving other development projects.
Area be mitigated to pre- 2 Establishing features to serve overall Project Area.
development conditions?
Select any or all of 1, 2, 3. On phase (or site) project basis within Project Area.
and /or 3, and explain below.
1. Shared facility (type & location of facility; design drainage area served; relationship to size of
Projec Area): (A Exhibit # __) L 7r� � � own strc c
J- � C J
2. For Overall Proiect Area (type & location of facilities): (A Exhibit
) �(G
Crrawtj Pc, ,+e)
C rC�UJ � 1
3. By ghase (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?
IL No i/ Yes Summarize type of BMP and extent of use:
y
0 O
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
Q Swales Ditches Inlets Valley gutters Outfalls
Culvert features Bridges Other
STORMWATER DESIGN GUIDELINES Page 11 of 26 APPENDIX. D: As TEC H. DedI SUM
Effective February 2007
SECTION IX
APPENDIX D — TECHNICAL DESIGN SUMMARY
Part 4 — Drainage Concept and Design Parameters
Continued (Page 4.3)
Stormwater Management Concept (continued)
Within Proiect Area Of Multi -Phase Project (continued)
Will Project Area include bridge(s) or culvert(s)? V No Yes Identify type and
general size and In which phase(s).
If detention /retention serves (will serve) overall Project Area, describe how it relates to subject
phase or site p (physical location, pathway(s), construction sequence):
(� KC -K e
l �' �NV� p "� - L,(0►�n � CGS'PC K d e u clop^? V%� I CO J ICjCJ
(0 5�s Se 51 - f " d: 5t4 C- 5 " J ,. '4o
6 s(�� ;.�5 Cr ape Ar - �e r ! 4- v...
Within Or Serving Subject Property (Phase, or Site)
If property part of larger Project i�cFea, 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?
C�-
Steepest side slopes:
Usual front slopes:
Usual back slopes:
N
Flow line slopes: least
Typical distance from travelway:
v o
typical greatest
(Attached Exhibit #
M�
M I
Are longitudinal culvert ends in compliance with B -CS Standard Specifications?
m
Q
Yes No, then explain:
At inter ctions or otherwise, do valley gutters cross arterial or collector streets?
a
6 }
E m
No Yes If yes explain:
I N
Are valley gutters proposed to cross any street away from an intersection?
Q, z
No Yes Explain: (number of locations ?)
y C
Q @
STORMWATER DESIGN GUIDELINES Page 12 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 4.4)
Stormwater Management Concept (continued)
Within Or Serving Subject Property (Phase, or Site) (continued)
� A Greatest Z. d o 3
Gutter line slopes: Least O ° o Usual D. °
Are inlets recessed on arterial and collector streets? Yes No If "no ",
identify where and why.
N lA-
Will inlets capture 10 -year design tormflow to prevent flooding of intersections (arterial
with arterial or collector)? Yes No If no, explain where and why not.
-o
a�
Will inlet size and placement prevent exceeding allowable water spread for 10 -year
design storm throughout site (or phase)? _LZ Yes No If no, explain.
5 l l Nt�l C
Sag curves Are inlets placed at low points? Yes No Are inlets and
C
conduit sized to prevent 100 -year stormflow from ponding at greater than 24 inches?
Y es No Explain "no" answers.
3
Q
ee NvJ
L
T
Will 100 -yr stormflow be containedJp combination of ROW and buried conduit on
Q
whole length of all streets? es No If no, describe where and why.
designs for curb, gutter, and inlets comply with B -CS Technical Specifications?
Y Do
es No If not, describe difference(s) and attach justification.
Are any 12 -inch laterals used? No Yes Identify length(s) and where
used.
N
Pipe
Pipe runs between system
pica[ id
Ty Longest 'I _Pn`6
>_
points (feet):
a�
Are junction boxes used at each bend? Yes No If not, explain where
N
and why.
c O
19 z
E
N
Are downstream soffits at or below upstream soffits?
Least amount that hydraulic
Yes IL/ No If not, explain where and why:
grade line is below gutter line
(system-wide):
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
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).
w
1) Watercourse (or system), velocity, and angle?
: a 0
E
2) Watercourse (or system), velocity, and angle?
� o
01 'sC r
�=
E °)
(D E
JM
3) Watercourse (or system), velocity, and angle?
�v
O
o
CL
E
For each outfall above, what measures are taken to prevent erosion or scour of
�
receiving and all facilities at juncture? _
1) �C ��7, �4� )fY� i �� � 1L1 j � ! ► S O!'ICP
N
2) �:�rc;0
�
1
0
3)
Are swale(s) situated along property lines between properties? No Yes
Number of instances: For each instance answer the following questions.
Surface treatments (including low -flow flumes if any):
y
N
N y
n D
Flow line slopes (minimum and maximum):
ca
I 0
° o
Z
� I
m
Outfall characteristics for each (velocity, convergent angle, & end treatment).
3
N
N
Q
Will 100 -year design storm runoff be contained within easement(s) or platted drainage
ROW in all instances? Yes No If "no" explain:
STORMWATER DESIGN GUIDELINES Page 14 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
Effective February 2007 As Revised February 2009
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, r Site) (continued)
Are roadside ditches used? No Yes If so, provide the following:
W 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
Q
? Yes No Are all ditch sections trapezoidal and at least 1.5 feet deep? p
Z
For any "no" answers provide location(s) and explain:
co
0
Q!
If conduit is beneath a swale, provide the following information (each instance).
Instance 1 Describe general location, approximate length:
U)
Is 100 -year design flow contained in conduit/swale combination? Yes No
"no" explain:
U If
0 M
Space for 100 -year storm flow? ROW Easement Width
Z ,c
Swale Surface type, minimum
Conduit Type and size, minimum and maximum
m
and maximum slopes:
slopes, design storm:
c
0
cl'
c m
Inlets Describe how conduit is loaded (from streets /storm drains, inlets by type):
C �^
m c
@
t
U L
C .O
0 o
Access Describe how maintenance access is provided (to swale, into conduit):
o
a�
— c
Instance 2 Describe general location, approximate length:
a� 0
u) N
c
Is 100 -year design flow contained in conduit/swale combination? Yes No
o
If "no" explain:
c CL
E a)
Space for 100 -year storm flow? ROW Easement Width
o
Swale Surface type, minimum
Conduit Type and size, minimum and maximum
m
and maximum slopes:
slopes, design storm:
c m
N
Inlets Describe how conduit is loaded (from streets /storm drains, inlets by type):
a00
m c
� o
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
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
a
E W
L
*7- ui
Is 100 -year design flow contained in swale? Yes No Is swale wholly
C }
within drainage ROW? Yes No Explain "no" answers:
a)
a00i
Access Describe how maintenance access is provide:
L 0
Z
I
o
Instance 2 Describe general location, approximate length, surfacing:
v
a�
0
W
oo E
3 M
Is 100 -year design flow contained in swale? Yes No Is swale wholly
U) L
within drainage ROW? Yes No Explain "no" answers:
0
N O
W
Access Describe how maintenance access is provided:
U
B
7
Q
Instance 3. 4, etc. If swales are used in more than two instances, attach sheet
providing all above information for each instance.
"New" channels: Will any area(s) of concentrated flow be channelized (deepened,
widened, or straightened) or otherwise altered? No Yes If only slightly
shaped, see "Swales" in this Part. If creating side banks, provide information below.
.�
Will design replicate natural channel? Yes No If "no ", for each instance
o n
describe section shape & area, flow line slope (min. & max.), surfaces, and 100 -year
o w
design flow, and amount of freeboard:
°-
N
Instance 1:
U)
c
E
a)
o I
Instance 2:
CL
0
Z
Instance 3:
m
s
U
STORMWATER DESIGN GUIDELINES Page 16 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 4.8)
Stormwater Management Concept (continued)
Within Or Serving Subject Property (Phase, or Site) (continued)
Existing channels (small creeks): Are these used? V No Yes
If "yes" provide the information below.
Will small creeks and their floodplains remain undisturbed? Yes No How
many disturbance instances? Identify each planned location:
For each location, describe length and general type of proposed improvement
(including floodplain changes):
For each location, describe section shape & area, flow line slope (min. & max.),
surfaces, and 100 -year design flow.
a
m
c
c
Watercourses (and tributaries): Aside fr m fringe changes, are Regulatory
0
Watercourses proposed to be altered? No Yes Explain below.
c
Submit full report describing proposed changes to Regulatory Watercourses. Address
E
E
existing and proposed section size and shape, surfaces, alignment, flow line changes,
>
length affected, and capacity, and provi full documentation of analysis procedures
a
an data. Is full report submitted? y Yes No If "no" explain:
a�
c
M
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.
�tk
Will 100 -year flow be contained with one foot of freeboard? Yes No If
not, identify location and explain:
Are ROW / easements sized to contain channel and required maintenance space?
Yes No If not, identify location(s) and explain:
STORMWATER DESIGN GUIDELINES Page 17 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
Effective February 2007 As Revised February 2009
SECTION IX
APPENDIX D - TECHNICAL DESIGN SUMMARY
Part 4 — Drainage Concept and Design Parameters
Continued (Page 4.9)
Stormwater Management Concept (continued)
Within Or Serving Subject Property (Phase, or Site) (continued) '`' sY " ✓i aN i r
How many facilities for subject property project? For each provide info. below.
For each dry-type facilitiy:
Facility
1
Facility
2
Acres served & design volume + 10%
100 -yr volume: free flow & plugged
Design discharge (10 yr & 25 yr)
Spillway crest at 100 -yr WSE?
yes no
yes no
Berms 6 inches above plugged WSE?
yes no
yes no
Explain any "no" answers:
y
N
}
I For
each facility what is 25 -yr design Q, and design of outlet structure?
Facility 1:
0
Z
Facility 2:
I
Do outlets and spillways discharge into a public facility in easement or ROW?
Facility 1: Yes No Facility 2: Yes No
a
If "no" explain:
m
0
CL
0
CL
For each, what is velocity of 25 -yr design discharge at outlet & at spillway?
4)
Facility 1: & Facility 2: &
L)
Are energy dissipation measures used? No Yes Describe type and
LL
location:
0
c
m
a�
For each, is spillway surface treatment other than concrete? Yes or no, and describe:
Q
Facility 1:
Facility 2:
For each, what measures are taken to prevent erosion or scour at receiving facility?
Facility 1:
Facility 2:
If berms are used give heights, slopes and surface treatments of sides.
Facility 1:
Facility 2:
STORMWATER DESIGN GUIDELINES Page 18 of 26 APPENDIX. D: TECH. UESKiN suMM
Effective February 2007 As Revised February 2009
SECTION IX
APPENDIX D - TECHNICAL DESIGN SUMMARY
Part 4 — Drainage Concept and Design Parameters
Continued (Page 4.10)
Storinwater 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;
U)
a�
Li :3
Facility 2:
0 c
0
0
4)
o For
additional facilities provide all same information on a separate sheet.
Are parking areas to be used for detention? No Yes What is
maximum depth due to required design storm?
Ro side 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:
rn
c
o Are
culverts parallel to public roadway alignment? Yes No Explain:
U �
(0
I Q
Creeks at Private Drives: Do private driveways, drives, or streets cross drainage
ways that serve Above - Project areas or are in public easements/ ROW?
°
IV
No Yes If "yes" provide information below.
N I
How many instances? Describe location and provide information below.
Location 1:
U
2
Location 2:
Location 3:
For each location enter value for:
1
2
3
Design year passing without toping travelway?
Water depth on travelway at 25 -year flow?
Water depth on travelway at 100 -year flow?
For more instances describe location and same information on separate sheet.
STORMWATER DESIGN GUIDELINES Page 19 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
Effective February 2007 As Revised February 2009
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? 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:
Arterial or Mai or Collector Streets: Will culverts serve these types of roadways?
N No
Yes How many instances? For each identify the
(D
location and provide the information below.
m
Instance 1:
>_ a
Instance 2:
I °'
C
Instance 3:
c
0
0 m
Yes or No for the 100 -year design flow:
1
2
3
E
o
Headwater WSE 1 foot below lowest curb top?
c
Spread of headwater within ROW or easement?
E
rn )
Is velocity limited per conditions (Table C -11)?
"no"
Explain any answer(s):
o c
0.9
N U
3 �
0
o -0
Minor Collector or Local Streets: Will culverts serve these types of streets?
L)
No Yes How many instances? for each identify the
"a
location and provide the information below:
am
cL
Instance 1:
N c
Instance 2:
M
Z
Instance 3:
U)
2
For each instance enter value, or "yes" / "no" for:
1
2
3
U fII
0 y
Design yr. headwater WSE 1 ft. below curb top?
Q
100 -yr. max. depth at street crown 2 feet or less?
E
Product of velocity (fps) & depth at crown (ft) = ?
,Q
Is velocity limited per conditions (Table C -11)?
Limit of down stream analysis (feet)?
Explain any "no" answers:
STORMWATER DESIGN GUIDELINES Page 20 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
Effective February 2007 As Revised February 2009
SECTION IX
APPENDIX D - TECHNICAL DESIGN SUMMARY
Part 4 — Drainage Concept and Design Parameters
Continued (Page 4.12)
Stormwater Management Concept (continued)
Within Or Serving Subject Property (Phase, or Site) (continued)
All Proposed Culverts: For all proposed culvert facilities (except driveway /roadside
ditch intersects) provide information requested in next eight boxes.
Do culverts and travelways intersect at 90 degrees? Yes No If not,
identify location(s) and intersect angle(s), and justify the design(s):
Does drainage way alignment change within or near limits of culvert and surfaced
approaches thereto? No Yes If "yes" identify location(s), describe
change(s), and justification:
Are flumes or conduit to discharge into culvert barrel(s)? No Yes If yes,
identify location(s) and provide justification:
Are flumes or conduit to discharge into or near surfaced approaches to culvert ends?
No Yes If "yes" identify location(s), describe outfall design treatment(s):
c
w
c
0
U
N
>
Is scour /erosion protection provided to ensure long term stability of culvert structural
�j
components, and surfacing at culvert ends? Yes No If "no" Identify
locations and provide justification(s):
Will 100 -yr flow and spread of backwater be fully contained in street ROW, and /or
drainage easements/ ROW? Yes No if not, why not?
Do appreciable hydraulic effects of any culvert extend downstream or upstream to
neighboring land(s) not encompassed in subject property? No Yes If
"yes" describe location(s) and mitigation measures:
Are all culvert designs and materials in compliance with B -CS Tech. Specifications?
Yes No If not, explain in Special Design Section of this Part.
STORMWATER DESIGN GUIDELINES
Effective February 2007
Page 21 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
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)
Is a bridge included in plans for subject property project? V 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�
rn
.
A M L
W
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
,n 4.,L
it
C7
Plan (SW3P)
established for
,
�Cc �tAZ,r e
w
project constr tion?
7 Yes
M
No
Special Designs — Non - Traditional Methods
Are any non - traditional methods (aquatic echosystems, wetland -type detention, natural stream
repli tion, BMPs for water quality, etc.) proposed for any aspect of subject property project?
No Yes If "yes" list general type and location below.
Provide full report about the proposed special design(s) including rationale for use and
expected benefits. Report must substantiate that stormwater management objectives will not
be compromised, and that maintenance cost will not exceed those of traditional design
solution(s). Is report provided? Yes No If "no" explain:
STORMWATER DESIGN GUIDELINES
Effective February 2007
Page 22 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
As Revised February 2009
SECTION IX
APPENDIX D — TECHNICAL DESIGN SUMMARY
Part 4 — Drainage Concept and Design Parameters
T Continued (Page 4.14)
Stormwater Management Concept (continued)
Within
Or Serving Subject Property (Phase, or Site) (continued)
Special Designs - Deviation From B -CS Technical Specifications
If any design(s) or material(s) of traditional runoff - handling facilities deviate from provisions of
B -CS Technical Specifications, check type facility(ies) and explain by specific detail element.
Detention elements Drain system elements Channel features
Culvert features Swales Ditches Inlets Outfalls
Valley gutters Bridges (explain in bridge report)
In table below briefly identify specific element, justification for deviation(s).
Specific Detail Element
Justification for Deviation (attach additional sheets if needed)
1)
2)
3)
4)
5)
Have elements been coordinated with the City Engineer or 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? Yes No
Briefly summarize the range of applicatiorss made of the Rational Formula:
^ J - �, j ( - 1 yo�o
What is the size and location of largest Design Drainage Area to which the Rational Formula
has been applied? 2•S acres Location (or identifier): 0 k- 46 � ..6Al4 A
C TkvAo'6�'ve r. a - (QEDe e( 6C -- Zd.'76 14-c e
STORMWATER DESIGN GUIDELINES Page 23 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
Effective February 2007 As Revised February 2009
SECTION IX
APPENDIX D - TECHNICAL DESIGN SUMMARY
Part 4 — Drainage Concept and Desiqn Parameters T Continued
(Page 4.15)
Design Parameters (continued)
Hydrology (continued)
In making deterrr�inations for time of concentration, was segment analysis used?
No Yes In approximately what percent of Design Drainage Areas? SJ %
As to intensity- duration - frequency and rain depth criteria for determi ing runoff flows, were any
criteria other than those provided in these Guidelines used? No Yes If "yes"
identify type of data, source(s), and where applied:
For each of the stormwater management features listed below identify the storm return
frequencies (year) analyzed (or checked), and that used as the basis for design.
Feature
Analysis Year(s)
Design Year
Storm drain system for arterial and collector streets
1U t.1 -
NIA-
Storm drain system for local streets
10 J' 1 0
1 Q
Open channels
N) A-
V I A
Swale /buried conduit combination in lieu of channel
r
,
Swales
Roadside ditches and culverts serving them
i
u
Detention facilities: spillway crest and its outfall
Detention facilities: outlet and conveyance structure(s)
11
Detention facilities: volume when outlet plugged
Culverts serving private drives or streets
Culverts serving public roadways
,
I'
Bridges: provide in bridge report.
I t
Hydraulics
What is the range of design flow velocities
as outlined below?
Design flow velocities;
Gutters
Conduit
Culverts
Swales
Channels
Highest (feet per second)
q
--
Lowest (feet per second)
3
—
—
Streets and Storm Drain Systems Provide the summary information outlined below:
Roughness coefficients used: For street gutters: 0 0 1 8
For conduit type(s) H 10 PrL Coefficients: 0.613 0.013
.oIZ
STORMWATER DESIGN GUIDELINES Page 24 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
Effective February 2007 As Revised February 2009
SECTION IX
APPENDIX D - TECHNICAL DESIGN SUMMARY
Part 4 — Drainage Concept and Design Parameters
Continued (Page 4.16)
Design Parameters (continued)
Hydraulics (continued)
Street and Storm Drain Systems (continued)
For the following, are as mptions other than allowable per Guidelines?
Inlet coefficients? V No Yes Head and friction losses No Yes
Explain any "yes" answer:
In conduit is velocity generally increased in the downstream direction? Yes No
Are elevation drops provided at inlets, manholes, and junction boxes? — Yes No
Explain any "no" answers:
Are hydraulic grade lines calculated d 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:
T . , tw'41, , �
ri
pen Channels If a HEC analysis is utilized, does it follow Sec VI.F.5.a? Yes No
Outside of straight sections, is flow regime within limits of sub - critical flow? Yes No
If "no" list locations and explain:
Culverts If plan sheets do not provide the following for each culvert, describe it here.
For each design discharge, will operation be outlet (barrel) control or inlet control?
NfA
Entrance, friction and exit losses:
NIA
Bridges Provide all in bridge report
a 1 UMMVVA i tK Ut5l(3N 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
C xceu 5P,JfCdsr,,,�
I l` �c �� -4-W, e r Q-
I ✓G�jo��
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:
C6W fI ;e f w �: �1� C de 5-'5v\ f
r
Q 6c S ys ��,�(�`►� s
Attestation
Provide attestation to the accuracy and completeness of the foregoing 6 Parts of this Technical
Design Summary Drainage Report by signing and sealing below.
'This report (plan) for the drainage design of the development named in Part B was prepared
by me (or under my supervision) in accordance with provisions of the Bryan/College Station
Unified Drainage Design Guidelines for the owners of the property. All licenses and permits
required by any and all state and federal regulatory agencies for the I k ed drainage
improvements have been issued or fall under applicable general per pF Ft
�P ..••..•T
(Affix Sear k •• .
g......... y
„.......
Licen d Pro essional Engineer �, JOSEPH, P
r� 9...... 66889 •
8 g 1 t O 'AFG►STE,P.� O �j�i
State of Texas PE No. ��-3 -0
1w)e
(if 4 4S3 B
STORMWATER DESIGN GUIDELINES Page 26 of 26 APPENDIX. D: TECH. DESIGN SUMMARY
Effective February 2007 As Revised February 2009
APPENDIX B
Drainage Area Calculations
Castle Rock Subdivision - Phase 4
Drainage Area Summary
Area #
Area, A
(acres)
C
tc
(min)
10 year storm
100 year storm
I
(iNhr)
Qio
(cfs)
Itoo
(in /hr)
Qioo
(cfs)
401
2.870
0.40
32.8
4.679
5.37
6.405
7.35
402
1.180
0.46
32.0
4.749
2.58
6.498
3.53
403
0.430
0.60
10.0
8.635
2.23
11.639
3.00
404
0.190
0.60
10.0
8.635
0.98
11.639
1 1.33
405
0.210
0.60
10.0
8.635
1.09
11.639
1.47
406
0.220
0.60
10.0
8.635
1.14
11.639
1_54
407
0.190
0.60
10.0
8.635
0.98
11.639
1.33
408
0.630
0.60
15.2
7.148
2.70
9.671
3.66
409
0.690
0.60
15.6
7.057
2.92
9.551
3.95
411 A
0.140
0.60
10.0
8.635
0.73
11.639
0.98
411 B
0.050
0.60
10.0
8.635
0.26
11.639
0.35
412
0.210
0.60
10.0
8.635
1.09
11.639
1.47
20.6
6.111
2.31
8.301
3.14
414A
20.1
6.193
1.67
8.408
2.27
10.0
8.635
2.07
11.639
2.79
L
&0.6 300.6 0
20.0
6.20
9.54
8.430
12.95
The Rati onal Method:
Q = CIA
Q = Flow (cfs)
A = Area (acres)
C = Runoff Coeff.
I = Rainfall Intensity (in /hr)
Brazos County:
I = b / (t +d)°
t = Time of concentration (min)
10 year storm
b = 80
d = 8.5
e = 0.763
100 year storm
b = 96
d = 8.0
e = 0.730
tc = U(V" 60)
L = Length (ft
V = Velocity (ft/sec)
APPENDIX C
Depth of Flow in Gutter Calculations
Castle Rock Subdivision
Phase 4
Depth of Flow in Gutter
(Refer to Exhibit A for Gutter Locations)
Laydown Curb - 10 -yr storm max design depth - 4"
Transverse (Crown) slope ( ft/ft)
27' street = 0.0330
Straight Crown Flow (Solved to find actual depth of flow in g utter, v):
Q = 0.56 ' (z/n) ' S 112 . ya3 A y = (Q / 10.56 ' (z/n) • S }
n = Roughness Coefficient = 0.018
S = Street/Gutter Slope (ft/ft)
y = Depth of flow at inlet (ft)
z = Reciprocal of crown slope:
27' street = 30
10 -year storm
i 410 Yio..d..i
(in/hr) I WS) (ft) I (in)
4.749 2.58 0.270 3.24
8.635 3.39 0.300 3.59
100 -year storm
1 0100 Y100
(in/hr) (cfs) (ft) (in)
6.498 3.53 0.304 3.65
11.639 4.57 0.335 4.02
Gutter
Location
2A
2B
A
C
0.46
0.60
Slope
( ft/ft)
0.0080
0.0080
tc
(min)
32.0
10.0
Area #
402
405
(acres)
1.180
0.654
3q
3B
403
404
0.109
0.632
0.60
0.60
0.0080
0.0080
10.0
10.0
8.635
8.635
0.56
3.27
0.153
0.296
1.84
3.55
11.639
11.639
0.76
4.41
T33
4A
4B
407
409
0.190
0.690
0.60
0.60
0.0080
0.0080
10.0
10.0
8.635
8.635
0.98
3.57
0.188
0.306
2.26
3.67
11.639
11.639
1.33
4.82
SA
5B
406
408
0.220
0.630
0.60
0.60
0.0080
0.008 0
10.0
10.0
8.635
8.635
1.14
3.26
0.199
0.295
2.39
3.54
11.639
11.639
2.67
3
T4.40O.330
6A
413
0.630
0.60
0.0100
20.6
6.111
2.31
0.249
2.99
8.301
3.35
7q
7B
414A
414B
0.450
0.400
0.60
0.60
0.0100
0.0080
20.1
10.0
6.193
8.635
1.67
2.07
0.220
0.249
2.65
2.99
8.408
11.639
2.27
2.79
0.
0.279
2.97
3.34
L 8A
411A
411 B
0.140
0.050
0.60
0.60
0.0010
0 .0080
10.0
10.0
8.635
8.635
0.73
0.26
0.248
0.114
2.98
1.37
11.639
11.639
0.98
0.35
0.278
0.128
3.33
1.53
Laydown Curb - 10 -yr storm max design depth - 4"
Transverse (Crown) slope ( ft/ft)
27' street = 0.0330
Straight Crown Flow (Solved to find actual depth of flow in g utter, v):
Q = 0.56 ' (z/n) ' S 112 . ya3 A y = (Q / 10.56 ' (z/n) • S }
n = Roughness Coefficient = 0.018
S = Street/Gutter Slope (ft/ft)
y = Depth of flow at inlet (ft)
z = Reciprocal of crown slope:
27' street = 30
APPENDIX D
Storm Sewer Inlet Design Summary
Castle Rock Subdivision - Phase 4
Storm Sewer Inlets on Grade - Design Analysis
Inlet
Length
Street
Q10
L10, ft.
Bypass
Q10
L100, ft.
Bypass
No
ft
Slope %
cfs
Design
cfs
cfs
Design
cfs
0.529
6.35
7" 5 4.57 0.486
5.83
6.35
0.605
7.26
8 5 0.98 0.174
2.09
6
5
1.00%
2.31
11.14
0.83
3.14
12.67
1.29
Castle Rock Subdivision - Phase 4
Storm Sewer Inlets in Sump - Design Analysis
Inlet Length Q10 D10 D10 Q100 D100 D100
No. ft. cfs ft. in. cfs ft. in.
2 5 3.67 0.420
5.04
5.00
0.516
6.19
3 5 3.21 0.384
4.61
4.33
0.469
5.62
4 5 3.90 0.437
5.24
5.28
0.535
6.42
5 5 3.84 0.433
5.19
5.2
0.529
6.35
7" 5 4.57 0.486
5.83
6.35
0.605
7.26
8 5 0.98 0.174
2.09
1.33
0.213
2.56
" Includes bypass flow from upstream inlets on
grade
Assume 10% clogging for design
Castle Rock Subdivision - Phase 4
Storm Sewer Grate Inlets in Sump -
Design Analysis
Inlet Open Area Q10 D10
D10
Q100
D100
D100
No. sf cfs ft.
in.
cfs
ft.
in.
1 4.52 5.37 0.243 2.92 7.35 0.455 5.46
Grate is an East Jordan Iron Works 36" grate, V -5736
Assume 50% clogging for design
APPENDIX E
Storm Sewer Pipe Design Summary
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EXHIBIT A
Drainage Area Map