HomeMy WebLinkAbout47 DP Castlegate Sub Sec II 03-39 2270 Greensprairie Rd WFOR OFFICE USE ONLY
P&Z Case No .: 03 -rosoo I )-c:;
Date Submitted : ~(z-g Io~
C1 ~20
~L-
FINAL PLAT APPLICATION bp LB.-~
(Check one) 0 Amending
($300 .00)
WF'inal
($400.00)
0 Vacating
($400 .00)
D Replat
($600 .oor
·includ es publi c he aring fee
The following items must be submitted by an established filing deadline date for P&Z Commission consideration.
MINIMUM SUBMITTAL REQUIREMENTS:
~ Filing Fee (see above) NOTE : Multiple Sheets -$55.00 per additional sheet
Variance Request to Subdivision Regulations -$100 (if applicable)
hl Development Permit Application Fee of $200 .00 (if applicable).
[0' Infrastructure Inspection Fee of $600 .00 (applicable if any public infrastructure is being constructed)
~ Application completed in full.
~ T hirteen (13) folded copies of plat. (A signed mylar original must be submitted after staff review .)
~ One (1) copy of the approved Preliminary Plat and/or one (1) Master Plan (if applicable).
~ Paid tax certificates from City of College Station, Brazos County and College Station l.S.D .
0 A copy of the attached checklist with all items checked off or a brief explanation as to why they are not.
§ Two (2) copies of public infrastructure plans associated with this plat (if applicable).
Parkland Dedication requirement approved by the Parks & Recreation Board, please provide proof of
approval (if applicable).
NAME OF SUBDIVISION ltl.'-zfte__qa,-fL ?Mhd_i Vt~QY] -Se.c),'m_ If .
SPECIFIED LOCATION OF PROPOSED SUBDIVISION (Lot & Block) 11.JfS,f ofS# ~ ovi6reen.s Pr0v1dci2d.
APPLICANT/PROJECT MANAGER'S INFORMATION (Primary Contact for the Project):
Name 6r{t'.,(}'2 ·prttirle,, J:.vivtsfur cs, U-d ~ Walla.Lg Pftu'U.µps
Street Address L.\L\jo Ca..sfl.R~ J)n' ~
Zip Code 17'tf/\ City Co ( ( ~e 'da--h'~ State _TI<---+->------
Phone Numoer (31q) ftt10 -]2-50 Fax Number __.(.,.......1_._]q-'--o#-) ~/rfl ......... O~--' O_Lf_._{ __ _
CURRENT PROPERTY OWNER'S INFORMATION : (All owners must be identified . Please attach an
additional sheet, if necessary) _ .
Name (2.,V-UX\C., \);a_trLL Tuvi<i>fvrS LJ-J E-Mail ________ _
Street Address 4--A;-ql)_ Ca ~ito~Jdri v(
City C-o l~U'f St~ 'OV\ State n
Phone Number @Ii4}(i]O ---J-Z.,C;20
ARCHITECT OR ENGINEER'S INFORMATION :
Name ( ~oe. SrliuJl'h f . f . -TeteoV\
Street Address \101 QY-~CA..W'l K..oo..d
City [o\\~ ~ State n
Phone Num~~ l±Lct)lJ1o -J 1 \ \
1-Aug -02
Zip Code 'JJf4 S-
Fax Number (11q)Wo-tell-(
E-Mail j oesckv_lh e -l--exc-0vt -~e_+
1 of 5
Acreage Total Property I Z. Oq cJ ()V Total #Of Lots 4 3 R-0-W Acreage }. 128 ac-.
Existing Use: \J0£a.()t . . Proposed Use : ~i~W fju'(/a.A-( tf»idc'.li1:h'a_(
Number Of Lots By Zoning District __!t2__ I J12I2.:rl __ /_ 1 _ I __
Average Acreage Of Each Residential Lot By Zoning District:
DJli I ffi)-~ I I
Floodplain Acreage--JJ-4.'-'~""""----------------------------
A Statement Addressing Any Differences Between The Final Plat And Approved Master Development Plan
And/Or Preliminary Plat (If Applicable):
w p.,
Requested Variances To Subdivision Regulations & Reason For Same : PDD -1:\ 1:::m-lrta
Requested Oversize Participation : -~~C~~~e-/ _________________ ~ _____ _
Total Linear Footage of
Proposed Public:
2<J 3Z.: Streets
:319 Q' Sidewalks
I =32--S( Sanitary Sewer Lines
301J..; Water Lines
Channels
112' Storm Sewers
Bike Lanes I Paths
Parkland DediGation due prior to filing the Final Plat:
ACREAGE: (Prev{ulY.;1,"{ ~ccktcaJe.d)
__ # of acres to be dedicated + $__ development fee
__ # of acres in floodplain
# of acres in detention
__ # of acres in greenways
OR
FEE IN LIEU OF LAND :
#of Single-Family Dwelling Units X $556 = $ __
__ (date) Approved by Parks & Recreation Board
NOTE: DIGITAL COPY OF PLAT MUST BE SUBMITTED PRIOR TO FILING.
The applicant has prepared this application and certifies that the facts stated herein and exhibits attached
hereto are true, correct and complete. The undersigned hereby requests approval by the City of College
Station of the above-identified final plat and attests that this request does not amend any covenants or ·
restrictions associated with this plat.
-5-21/'-0f
Date
1-Aug -0 2 2 of 5
SUPPLEMENTAL DEVELOPMENT PERMIT INFORMATION
Application is hereby made for th..e following development specific site/waterway alterations : \nfr11.$(Y\.l~ ~ UDll1 COn~tr\JdiWl
ACKNOWLEDGMENTS:
Wc.t.l la.c.L Th\\\\ D?
I, . design engineer/owner, hereby acknowledge or affirm that :
The information and conclusions contained in the above plans and supporting documents comply with the
current requirements of the City of College Station . Texas City Code, Chapter 13 and its associated Drainage
Policy and Design Standards. As a condition of approval of this permit application , I agree to construct the
improvements proposed in this application according to these documents and the requirements of Chapter 13
of the College Station City C de.
Contractor
CERTIFICATIONS: (for proposed alterations within designated flood hazard areas .)
A . I, __ certify that any nonresidential structure on or proposed to be on this site as part of this application
is designated to prevent damage to the structure or its contents as a result of flooding from the 100 year
storm .
Engineer Date
B . I, __ certify that the finished floor elevation of the lowest floor, including any basement , of any
residential structure, proposed as part of this application is at or above the base flood elevation established in
the latest Federal Insurance Administration Flood Hazard Study and maps, as amended .
s \ ... )J--i..
Date
D. I, , do certify that the proposed alterations do not raise the level of the 100 year flood above
elevation established in the latest Federal Insurance Administration Flood Hazard Study .
Engineer Date
Conditions or comments as part of approval : __
In accordance with Chapter 13 of the Code of Ordinances of the City of College Station , measures shall be
taken to insure that debris from construction . erosion , and sedimentation shall not be deposited in city streets ,
or existing drainage facilities . All development shall be in accordance with the plans and specifications
submitted to and approved by the City Engineer for the above named project. All of the applicable codes and
ordinances of the City of College Station shall apply .
1-Aug-0 2 3 o f 5
' . .,.
. .. .. :1 ..... ....
. ,
I
DEVELOPMENT PERMIT
PERMIT NO. 03-118 ~-v
Project: Castlegate Subdivision Section 11
COLLEGE STATION FOR AREAS OUTSIDE THE SPECIAL FLOOD HAZARD AREA
RE : CHAPTER 13 OF THE COLLEGE STATION CITY CODE
SITE LEGAL DESCRIPTION:
CASTELGATE SECTION 11
ALL LOTS
DATE OF ISSUE: 06/26/03
OWNER:
GREENS PRAIRIE INVESTORS LTD
4490 CASTLEGATE DR
COLLEGE STATION , TX 77845
SITE ADDRESS:
CASTELGATE SUBDIVISION
DRAINAGE BASIN:
Spring Creek
VALID FOR 12 MONTHS
CONTRACTOR:
TEXCON GENERAL CONTRACTORS
1707 GRAHAM ROAD
COLLEGE STATION , TX 77845
TYPE OF DEVELOPMENT: Full Development Permit
SPECIAL CONDITIONS:
All construction must be in compliance with the approved construction plans
All trees must be barricaded , as shown on plans, prior to any construction . Any trees not barricaded will not
count towards landscaping points. Barricades must be 1' per caliper inch of the tree diameter.
Erosion control per the approved plans must be in place for duration of the project.
The Contractor shall take all necessary precautions to prevent silt and debris from leaving the immediate
construction site in accordance with the approved erosion control plan as well as the City of College Station
Drainage Policy and Design Criteria . If it is determined the prescribed erosion control measures are ineffective
to retain all sediment onsite , it is the contractors responsibility to implement measures that will meet City , State
and Federal requirements. The Owner and/or Contractor shall assure that all disturbed areas are sodden and
establishment of vegetation occurs prior to removal of any silt fencing or hay bales used for temporary erosion
control. The Owner and/or Contractor shall also insure that any disturbed vegetation be returned to its original
condition , placement and state . The Owner and /or Contractor shall be responsible for any damage to
adjacent properties , city streets or infrastructure due to heavy machinery and/or equipment as well as erosion ,
siltation or sedimentation resulting from the permitted work .
Any trees required to be protected by ordinance or as part of the landscape plan must be completely fenced
before any operations of this permit can begin.
In accordance with Chapter 13 of the Code of Ordinances of the City of College Station , measures shall be
taken to insure that debris from construction , erosion , and sedimentation shall not be deposited in city streets ,
or existing drainage facilities .
I hereby grant this permit for development of an area outside the special flood hazard area . All development
shall be in accordance with the plans and specifications submitted to and approved by the City Engineer in the
development permit application for the above named project and all of the codes and ordinances of the City of
College Station that apply .
~ 1)~-D 1 -D3
Date
Owner/ Agent/Contractor Da
iZ:f#p.J
I
TEXCON GENERAL CONTRACTORS 18 -Jun -03
CONSTRUCTION COST ESTIMATE
CASTLEGATE SUBDIVISION
COLLEGE STAT ION , TEXAS
SECTION 11 -43 LOTS
Item Estima ted Unit Estimated
No . Description Quan tit y Price Cost
Sitework
1 M obilization/Layout 1.0 LS $10 ,000 .00 $10 ,000
2 Site Preparation 4 .0 AC $3 ,000 .00 $12 ,000
3 Sediment & Eros ion Control 1.0 LS $5,000 .00 $5 ,000
4 Topsoil Stripping & Replacement 1,000 CY $4.50 $4 ,500
5 Excavation 3 ,600 CY $3 .50 $12 ,600
6 Lime Stabilized Subgrade 11,400 SY $3 .25 $37 ,050
7 Concrete Curb & Gutter 5 ,530 LF $8 .00 $44,240
8 Base Material -6" depth 4 ,370 SY $6 .00 $26 ,220
9 Base Material -7" depth 4,960 SY $7 .00 $34 ,720
10 Asphalt Paving -1 1 /2" depth 9 ,330 SY $5 .00 $46 ,650
11 Con crete Apron 2,730 SF $5 .50 $15 ,015
12 ADA Ramp -regular 6 EA $350 .00 $2, 100
13 ADA Ramp -corner 8 EA $450 .00 $3,600
14 Concrete Sidewal k -4' wide 15 ,33 0 SF $3 .0 0 $45 ,990
15 Seed in g & Hydromulch 10,000 SY $0 .50 $5,0 00
16 End of roadway s ig ns 5 EA $150 .00 $750
Subtotal $305,435
Storm Drainage
17 Drainage Pip e -18" RCP -st ru ctural 45 LF $38 .00 $1,710
18 Drainage Pipe -24" RCP -structura l 75 LF $45 .00 $3 ,375
19 Drainage Pipe -30" RCP -structura l 24 0 LF $54 .00 $12 ,960
20 Dra in age Pip e -36" RCP -structural 180 LF $63 .00 $11 ,340
21 Bo x Cul v ert -4' x 3' -structural 45 LF $165.00 $7 ,425
22 Bo x Cul vert - 4 ' x 3' -non-structural 210 LF $155 .00 $32 ,550
23 Headwa ll/wingwalls -4'x3' box culvert EA $5,500 .0 0 $5 ,500
24 Inl ets 5' wide I Junction boxes 4 EA $2,400 .00 $9 ,600
25 Inlets 15' wide 1 EA $3,600.00 $3 ,600
26 Inl ets 20' wide 2 EA $4 ,200 .00 $8 ,400
27 Rock riprap 35 TON $50 .00 $1,750
28 Temporary drainage channel grading 320 LF $8 .00 $2,560
Subtotal $100,770
Water Lines
29 6" Water PVC CL200 (C900) structural 324 LF $26 00 $8,424
30 8" Water PVC C L200 (C900) structural 1,300 LF $30 .00 $39 ,000
31 12 " Water PVC CL200 (C900) structural 1,500 LF $42 .00 $63 ,000
32 Gate Valves -6" 2 EA $500 .00 $1 ,000
33 Gate Valv es -8" 5 EA $600 .00 $3,000
34 Gate Valves -12" 4 EA $1 ,500 .00 $6 ,000
35 M .J . Tees -8" x 6" 2 EA $300 .00 $600
36 M .J . Tees -12" x 6" 2 EA $500 .00 $1 ,000
37 M .J . Tees -12" x 8" 1 EA $600 .00 $600
38 M .J . Cross -12" x 8" 2 EA $700 .00 $1 ,400
39 M .J . Reducer -8" x 6" 1 EA $250 00 $250
40 M .J Bend -8" 22 .5 deg 2 EA $450 00 $900
41 MJ Be nd -8" 45 deg . 2 EA $500 00 $1,000
42 M .J . Bend -1 2" 90 deg 2 EA $500 00 $1 .000
Pag e I o f 2
' ,
43 Water Services 24 EA $750.00 $18 ,000
44 2" Blow off Assembly 2 EA $450.00 $900
45 Fire Hydrant Assembly 3 EA $2 ,200.00 $6 ,600
46 Relocate fire hydrant assembly 1 EA $250 .00 $250
47 Connect to existing line 2 EA $350.00 $700
Subtotal $153,624
Sanitary Sewer Lines
48 6" SOR 26 Pipe -st ruct; avg depth <1 O' 415 LF $30 .00 $12 ,450
49 6" SOR 26 Pipe -non-str; avg depth <1 O' 410 LF $20 .00 $8 ,200
50 6" SOR 26 Pipe -struct; avg depth 10'-12' 120 LF $35 .00 $4 ,200
51 6" SOR 26 Pipe -non-str ; avg depth 10 '-12' 370 LF $27 .00 $9 ,990
52 8" SOR 26 Pipe -struct ; avg depth <10' 565 LF $32 .00 $18 ,080
53 8" SOR 26 Pipe -non-str; avg depth < 1 O' 1,220 LF $23 .00 $28 ,060
54 8" SOR 26 Pipe -struct ; avg depth 10'-12' 130 LF $36 .00 $4 ,680
55 6" ASTM-02241-struct ; avg depth < 1 O' 20 LF $36 .00 $720
56 8" ASTM-02241-struct ; avg depth < 1 O' 40 LF $38 .00 $1 ,520
57 Cement Sand Embedment 76 LF $8 .00 $608
58 Sewer Services 25 EA $750 .00 $18 ,750
59 Future Sewer Services 17 EA $500 .00 $8 ,500
60 Manholes -average depth 8'-1 O' 7 EA $2 ,200 .00 $15 ,400
61 Manholes -average depth 10'-12 ' 5 EA $2,400.00 $12 ,000
62 Connect to existing line EA $1 ,000 .00 $1 ,000
Subtotal $144,158
Total Sitework $305,435
Total Storm Drainage $100 ,770
Total Water $153,624
Total Sanitary Sewer $144,158
TOTAL CONSTRUCTION I $703,9871
Engineering and Survey@ 6% $42,239
Contingency @ 5% $35, 199
TOTAL I $781,426J
Page 2 of 2
CERTIFICATION
I, Joseph P . Schultz, Licensed Professional Engineer No . 65889 , State of Texas , certify that this
report for the drainage design for the Castlegate Subdivision -Section 11, was prepared by me
in accordance with the provisions of the City of College Station Drainage Policy and Design
Standards for the owners hereof.
_,,,,,,,
--~£. OF r ,, ~ "' •••••••••••• ~-+-,, ~ .. · * ··.;ui •• 1*/ .... ,, ;-.; * . * ., ~ .................................... ~ ~:;~Q~~J! .. ~;..~9.~.Y.~g····~ ~~-P0\~ 65889 /$J '°~ '.T~ t<:.0 • ~ " •t~ "•.Cf ISTE?..Y··· ~ ~
"q \&.SI • • • • • • • • ...;:. 0 .,,
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GingeAJ. Urso , P .E.
TABLE OF CONTENTS
DRAINAGE REPORT
CASTLEGATE SUBDIVISION -SECTION 11
CE RTIFICATION ................................................................................................................................................................. 1
TABLE OF CONTENTS ....................................................................................................................................................... 2
LIST OF TABLES .................................................................................................................................................................. 2
INTRODUCTION .................................................................................................................................................................. 3
GENERAL LOCATION AND DESCRIPTION ................................................................................................................. 3
FLOOD HAZARD INFORMATION ................................................................................................................................... 3
DEVELOPMENT DRAINAGE PATTERNS ...................................................................................................................... 3
DRAINAGE DESIGN CRITERIA ....................................................................................................................................... 3
STORM WATER RUNOFF DETERMINATION .............................................................................................................. 4
DETENTION FACILITY DESIGN ..................................................................................................................................... 5
STORM SEWER DESIGN .................................................................................................................................................... 5
CONCLUSIONS ..................................................................................................................................................................... 6
APPENDIX A ......................................................................................................................................................................... 7
Storm Sewer Inlet Design Calculations
APPENDIX B ........................................................................................................................................................................ 10
Storm Sewer Pipe Design Calculations
APPENDIX C ....................................................................................................................................................................... 23
Temporary Drainage Channel Calculations
APPENDIX D ....................................................................................................................................................................... 25
Time of Concentration Calculations
EXHIBIT A ........................................................................................................................................................................... 29
Post-Development Drainage Area Map
LIST OFT ABLES
TABLE 1 -Rainfall Intensity Calculations ......................................................................................................... 4
TABLE 2 -Post-Development Runoff Information -Storm Sewer Design .................................................... 5
2
INTRODUCTION
DRAINAGE REPORT
CASTLEGATE SUBDIVISION -SECTION 11
The purpose of this report is to provide the hydrological effects of the construction of the
Castlegate Subdivision -Section 11, and to verify that the proposed stom1 drainage system
meets the requirements set forth by the City of College Station Drainage Policy and Design
Standards .
GENERAL LOCATION AND DESCRIPTION
The project is located on a portion of a 111.46 acre tract lo cated west of State Highway 6 along
the north side of Greens Prairie Road in Co ll ege Station, Texas . This report addresses Section
11 of this subdivision, which is made up of 12.095 acres . The site is predominantly pastureland
with approximately I 0% of the area wooded . The existing ground elevations range from
elevation 299 to elevation 318. The general location of the project site is shown on the vicinity
map in Exhibit A.
FLOOD HAZARD INFORMATION
The project site is located in the Spring Creek branch of the Lick Creek Drainage Basin . The
site is lo cated in a Zone X Area according to the Flood Insurance Rate Map prepared by the
Federal Emergency Management Agency (FEMA) for Brazos County, Texas and incorporated
areas dated 2-9-2000, panel number 48041C0205-D . Zone X Areas are determined to be
outside of the 500-year floodplain.
DEVELOPMENT DRAINAGE PATTERNS
Prior to development, the storm water runoff for Section 11 flows in an easterly direction until
it enters a tributary of Spring Creek. Ultimately, the runoff flows into Spring Creek and then
north to the proposed regional detention faci lity. Refer to the vicinity map in Exhibit A for the
location of this regional detention facility .
DRAINAGE DESIGN CRITERIA
The design parameters for the storm sewer are as follows:
• The Rational Method is utilized to determine peak storm water runoff rates for the storm
sewer design .
• Design Storm Frequency
Stom1 Sewer system
• Runoff Coefficients
Pre-development
I 0 and 100-year stom1 events
Post-development (single fami ly residential)
' -'
c = 0.30
c = 0 .55
• Rainfall lntensity val ues for Brazos County for a minimum time of concentration of 10
minutes can be found in Table I . Where a lon ger time of concentration was necessary, it is
noted in the respective table, a nd the intensities are calculated with the higher va lu es where
required.
• Time of Concentration, tc -Due to the small sizes of the drainage areas , most of th e
calculated times of concentration, tc, are less than 10 minutes . Therefore, a minimum tc of
10 minutes is us ed in most cases to determine the rainfall intensity valu es . Where a lon ger
time of concentration was necessary, it is noted and used accord in gly. Refer to Appendix D
for the methods and formulas used to compute these longer times of concentration.
STORM WATER RUNOFF DETERMINATION
The peak runoff values were determined in accordance with the criteria presented in the
previous section for the 5 , 10 , 25, 50, and 100-year storm events. The runoff coefficients are
based on the future development of this tract. The drainage areas for post-d e ve lopm e nt are
shown on Ex hibit A . Post-development runoff conditions for the storm sewer design are
summa ri z ed in Table 2 .
TABLE 1 -Rainfall Intensity Calculations
Rainfall Intensity Values (in/hr)
Storm le=
Event 10 min
15 7 .693
110 8 .635
12 5 9 .861
150 11 .148
1100 11.639
Brazos Co unty:
5 )".ear storm 10 )".ear storm
b = 76 b = 80
d = 8.5 d = 8 .5
e = 0 .785 e = 0.763
I = b I {tc+d)e
I = Rainfall Intensity (in/hr)
t c = L/(V*60)
tc =Time of concentration (m in)
L = Length (ft)
V =Velocity (ft/sec)
25 )".ear storm 50 )".ear storm 100 )".ear storm
b = 89 b = 98 b = 96
d = 8.5 d = 8 .5 d = 8.0
e = 0 .754 e = 0 .745 e = 0 .730
(Data taken from State Department of Highwa)".s and Public Tran sportation H)".draulic Manual. page 2-16)
TABLE 2 -Post-Development Runoff Information -Storm Sewer Design
Arna c 5 year storm 10 year storm 25 year storm 50 year storm 100 yea r storm
le Area# (acres) 15 Os 110 0 10 125 0 25 lso O so 1100
A, A2
c ,
Total
C 2 CrO(af
(min) (in/hr) (cfs) (in/hr) (cfs) (in/hr) (cfs) (in/hr) (cfs) (in/hr)
10-8 3.27 0.87 4.14 0 .55 0 .3 0 .50 31 .9 4 .167 8.58 4 .758 9 .80 5.472 1 1.27 6 .230 12 .83 6 .510 ---10-9 1.85 0.80 2.65 0.55 0 .3 0.47 24.4 4 .896 6 .16 5 .565 7 .00 6 .389 8 .03 7 .2 60 9 .13 7 .578
10 -10 0.18 0 0.18 0 .55 0.3 0 .55 10 7.693 0 .76 8.635 0 .85 9.861 0.98 11 .148 1.10 11.639
10-11 0.15 0 0.15 0 .55 0 .3 0.55 10 7.693 0 .63 8.635 0.71 9 .861 0.81 11 .148 0 .92 11 .639
11-1 3.21 0 3 .21 0.55 0 .3 0.55 10 7.693 13.58 8.635 15.24 9.861 17.41 11 .148 19.68 11 .639 --
11 -2 0.77 0 0.77 0.55 0 .3 0.55 10 7 .693 3.26 8.635 3.66 9.861 4 .18 11 .148 4 .72 11 .639
11 -3 3.36 0 3.36 0.55 0 .3 0 .55 10 7 .693 14 .22 8 .635 15.96 9.861 18.22 11.148 20.60 11 .639
11-4 0.4 1 0 0.4 1 0 .55 0.3 0 .55 10 7.693 1.73 8 .635 1.95 9.861 2 .22 11 .148 2 .51 11 .639
11 -5 0 .08 0 0 .08 0.55 0 .3 0 .55 10 7 .693 0 .34 8.635 0.38 9 .861 0.43 11 .148 0.49 11 .639
11 -6 0.30 2 .54 2.84 0 .55 0.3 0 .33 24 .7 4 .861 4 .51 5.527 5.12 6.345 5.88 7.211 6.68 7.528
The Rational Method :
Q=CIA I = b I (tc+d)0
Q = Flow (cfs)
A= Area (acres )
C = Runoff Coe ff .
le = Time of concent ra tion (min)
tc = L/(V*6 0)
L = Len gth (ft
V = V elocity (fl/sec)
I = Rainfall Intensity (in/hr)
Brazos County:
5 vear storm
b = 76
d = 8 .5
e = 0 .79
10 year storm
b = 80
d = 8.5
e = 0.76
DETE NTI ON FACILITY DESIGN
25 year storm
b = 89
d = 8 .5
e = 0 .75
50 year storm
b = 98
d = 8 .5
e = 0 .745
100 vear storm
b = 96
d = 8 .0
e = 0 .730
The detention fac ilit y handling the runoff from this site is a regiona l facility designed by LJA
Eng ineerin g & Surveying, Inc . A lso , a detention pond was constructed upstream of Cast legate
Drive to reduce the peak flow resulting from the Cast legate deve lopment. Refer to the vicinity
map in Exhibit A for the locations of the regional detention facility and the detention pond
upstream of Cast le gate Drive. The runoff from this project flows into existing drainages and
then into Spring Creek. The detention faci lit y is located adjacent to Spring Creek prior to
Spring Creek entering the State Highway 6 ri ght-of-way.
STORM SEWER DESIGN
The storm sewer piping for this project has been selected to be Reinforced Concrete Pipe
(RCP) m eeting the requirements of ASTM C-7 6, Class III pipe or precast concrete box sections
meet in g the requirements of ASTM C-789. The curb inlets and j un ction boxes wi ll be cast-in-
place concrete .
Appendi x A presents a summary of the storm sewer inlet design parameters and calcu lations.
The inlets were designed based on a I 0-year d esign stom1 . As per Co ll ege Station g uid e lin es,
the capacities of in lets in s ump were reduce d by I 0% to a ll ow for clogging .
Inlets for the residential streets were located to maintain a gutter flow depth of 5 " or less, a nd
inlets for Victo ri a Aven ue were located to maintain a g utt er flow depth of 7" or less. These
design depth s w ill prevent the spread of water from reachin g the crown of th e road fo r th e 10-
yea r stom1 eve nt. Refer to Append ix A for a summary of th e gu tt e r flow depths . The runoff
0 100
(cfs)
13.41
9.53
1.15
0.96 --20.55
4 .93
21 .51
2.62
0.51
6 .98
I
intercepted b y the proposed storm sewer inlets was calculated using the followin g equations.
The depth of flow in the gutter was determined by using the Straight Crown Flow equation.
The flow intercepted by Inlet 1101 (and Future Inlets 1104 & 1105) was calculated by using the
Capacity of Inlets On Grade equation. The capacities for the inlets in sumps (Inlets 1009 ,
1010 , 1102 & 1103) were calculated using the Inlets in Sumps , Weir Flow equation with a
maximum allowable depth of 7" (5" gutter flow plus 2" gutter depression). These equations
and the resulting data are also summarized in Appendix A.
Appendix B presents a summary of the storm sewer pipe design parameters and calculations.
All pipes are 18 " in diameter or larger. For pipes with 18 " and 24" diameters , the cross-
sectional area is reduced by 25%, as per College Station requirements. A summary of how this
was achieved is shown in Appendix B as well. The pipes and boxes for the storm sewer system
were designed based on the 10-year storm event, and most will also pass the 100-year storm
event without any headwater. Based on the depth of flow in the street determined for the 100-
year storm event, this runoff will be contained within the street right-of-way until it enters the
storm sewer system. As required by College Station , the velocity of flow in the storm sewer
pipe system is not lower than 2.5 feet per second, and it does not exceed 15 feet per second. As
the data shows , even during low flow conditions, the velocity in the pipes will exceed 2 .5 feet
per second and prevent sediment build-up in the pipes . The max imum flow in the storm sewer
pipe system will occur in Box No. 9. The maximum velocity for the pipe system in this
development w ill be 9.1 feet per second and will occur in Box No. 9. Appendix B contains a
summary of the Manning pipe calculations as well as flow diagrams mapping the flows through
the storm sewer system for the 10 and 100-year events.
The culvert at the intersection of Victoria Avenue and the future State Highway 40 has also
been designed and included in this report , even though it will not be constructed with
Castlegate Section 11 .
There will be a temporary drainage channel located at the end of Pipe 3. It will be a trapezoidal
channel 2.5 feet deep with 1 V:4H side slopes and a bottom width of 3 feet. The slope of the
channel will be 0.5%, and the resulting velocities will be 2.8 fps for the 10-year storm and 3.0
fps for the 100-year storm .
CONCLUSIONS
The construction of this project will increase the storm water runoff from this site. The
proposed storm sewer system should adequate ly control the runoff and release it into existing
drainages. As shown in the Castlegate Floodplain Analysis, the Castlegate Subdivision does
not have a significant effect on the 100-year floodplain water surface elevations or the
floodplain limits. Also, the regional detention facilit y should adequately control the peak post-
development runoff so that it will not have any impact on the properties downstream of the
Crowley Tract.
6
APPENDIX A
Storm Sewer Inlet Design Calculations
7
Castlegate Subdivisi o n
Section 11
Inlet Length Calculations
Inlets In Sump 1 O year storm 100 year storm
Inlet# Length Flow from A c a., Oe.,ryover Orotel O rot al+10'11. Y 10.actual L 10-Aeq'd• L 10-ac:lual O,oo O carryov•r
Area# (acres) (els) (els) from inlet# (els) (els) (ft) (in) (ft) (ft) (cfs) (els) from inlet#
1009 20' 10-9 2.65 0.47 6 .94 6 .94 7.63 0 .309 3.70 9.44 ------13 .83 20 10-8 4.14 0 .50 9 .85 9.85 10.84 0.352 4.23 13 .48
1010 5' 10-11 0.15 0 .55 0 .71 0 .71 0 .78 0.131 1.58 0 .96 ------------------1---1.29 5 10-10 0.18 0.55 0 .85 0.85 0 .94 0 .141 1.69 1.15
1102 20' 11 -3 3.36 0 .55 15 .96 3.67 1101 19 .63 21 .59 0.460 5.52 17 .77 21 .51 8.07 1101 -----20 -11-4 0 .41 0.55 1.95 1.95 2.14 0.193 2.32 2 .62
1103 5· 11-2 077 0.55 3.66 3.66 4 .02 0.243 2.91 3.33 5 4 .93 -------1 1-5 0 .08 0.55 0.38 0 .38 0.42 0.104 1.25 0 .51
Inlets On Grade 1 O year storm
Inlet#
1101
Fu iwe ! 10../
Future 1105
Le ngth Flow from y., a ....,,,ool O c apaclt Obypu• O capturad
Area# (ft) (In) (ft) (els) (els) (cfs)
15' 0.484 5.81 0.77 11 .57 3.67 11 .57 ----10' 0433 5.19 0 73 7 26 1.76 7.26 s---------------0.305 3.66 0.60 3.00 0.56 3.00
Transverse (Crown) slope (ftlftl
for res idential streets = 0 .033 (Fulure In/els 1104 & 1105)
for Victoria Aven ue= 0 .0315 (Inl ets 1009. 1010. 1101thru1103)
Stra ight Crown Flow (Solved to find actual depth of flow, y):
a= o.56 • (zln) • s '" • y'" <> y = (01 [0.56 • (zln) • s'"n'"
n =Roughness Coefficient= 0 .018
S = StreeVGutter Slope (ft/ft )
y = Depth of flow at inlet (ft)
Capacity of Inlets on grade :
0c = 0.7' [1/(H 1 -H2)]' [H, 512 -H2
512]
Oc =Flow capacity or inlet (cfs)
H, =a+ y
H2 = a = gutter depression (2" Standard ; 4" Recessed )
y = Depth of flow in approach gutter (ft)
Q C.,t)'O\lef O byp.tot• O c apt.to1t 010.Tot•I Y 100 O perloot
(cfs) I from inlet I (els) (cfs) (cfs) (ft) (In) (ft)
I
I
I
3.67 11 .57 15.25 0.542 6 .50 0 .83 -------------1.76 7.26 9.02 0.484 5.81 0 78 -------0.56 3.00 3.56 0.341 4.10
z = Reciprocal of crown slope
for residential st reets = 30
for Victoria Avenue = 32
Inlets In sumps. Weir Flow:
L = Q I (3 ' y'") <> y = (QI 3L)213
L = Length of inlet opening (ft)
Q = Flow at inl et (cfs)
y = total depth of flow on inlet (ft )
max y for inlet in sump = 7" = 0 .583'
0.63
Orot •I Orot al+t O ~ Y 100
(cfs) (els) (ft) (in)
9.44 10 .38 0 .561 6 .73
13.48 14 .82
0.96 1.06 3.46 I----0 .288
1.15 1.27
29 .58 32 .54 0 .704 8.45
2.62 2 .89
4.93 5.42 0.542 6 .50
0.51 0 .56
100 year storm
O e1pacity Ob.,.pa •• O c aptur •d Q C&lf)'OY&f
(cfs) (els) (els) (els) I Oom lnleU
12.48 8 .07 12 .48 I
7 BO 4.36 7.80 I
3.17 1.63 3.17 I
Obyp-1oul O upt-totl 0 100.foUI s L1c1 ... 1
(cfs) (cfs) (els) (ftlft) (ft)
8.07 ~ 20 .55 0.0125 15
4.36 7.80 12.16 00080 10 ---------1.63 3.17 4.80 0.0080 5
"' Q) ·c ::J
0 c
.11 ~ > <{
Castlegate Subdivision -Section 11
Depth of Flow in Street Gutter
10-year storm
Gutter A c Slope 010 Y 10-actual
Locati on (acres) (ft/ft) (cfs)
A 1 1.30 0 .55 0 .01 6 .17
-----
A 2 0 .85 0 .55 0 .01 4 .04
B1 0 .50 0 .55 0 .0232 2 .37
--
B2 0 .61 0 .55 0 .02 2 .90
0 1 0.69 0 .55 0 .02 3.28
--------
0 2 1.55 0 .55 0 .02 7 .36
C1 0 .92 0 .55 0 .008 4 .37 ----------
C2 2 .23 0 .55 0 .01 10 .59
- ---------
C3 3.21 0 .55 0 .0125 15 .25
- -------------
C4 2.44 0 .55 0 .01 11 .59
Transve rse (Crown) slope (ft/ft)
for residential streets = 0 .0330 (Locat ions A , B & D)
for Victoria Av e nue= 0 .0315 (Location C)
(ft) (in)
0 .360 4 .32
----
0 .307 3.68
0 .215 2 .58
--
0 .23 1 2.78
0 .249 2.99 ---
0 .337 4 .05
0 .32 4 3.89 ------
0.415 4 .98
---
0.476 5.7 1
------
0.467 5.60
Straight Crown Flow (Solved to find actual depth of flow in gutter, y):
Q = 0 .56 • (zln) • S 112 • y8 '3 <> y ={QI [0 .56 • (zln) • S 112]}318
n = Roughness Coefficient 0 .018
S = StreeUGutter Slope (ft/ft)
y = Depth of flow at inlet (ft)
z = Re ciproca l of crown slope :
for residential streets =
for Victoria Avenue =
30
32
(Locations A , B & D)
(Location C)
100-year storm
0 100 Y 100
(cfs) (ft) (in)
8.32 0.402 4 .83
5.44 0 .343 4 .12
3 .20 0 .240 2 .88 -
3.90 0 .259 3 .11
4.42 0 .279 3.34
9 .92 0 .377 4 .53
5.89 0 .362 4 .35
14 .28 0.464 5.57
-
20 .55 0 .532 6 .39 ---
15 .62 0 .522 6 .27
Note: For the residential streets , laydown curb is used , therefore , the ma ximum allowable depth
of flow in the gutter is 5". For Victoria Avenue , standard curb is used , therefore , 7" of depth is
allowed in the gutter.
APPENDIX B
Storm Sewer Pipe Design Calculations
10
Castlegate Subdivision
5 f 11 p· C I I f ec ion -me a cu a ions
Inlet Outlet 10 year storm 100 year storm
Pipe/Box# Size Length Slope
Invert Elev Invert Elev *Actual Flow Des ign Flow V10 Travel Time, tn0 •Actual Flow Des ign Flow V1 00 % Full % Full
(in) (ft) (%) (ft) (ft) (cfs) (cfs) (fps) (sec) (min) (cfs) (cfs) (fps)
··3 36 177 .7 0.45 293 .58 292.78 37.19 6 .6 73 .8 27 0.45 50 .12 7 .1 100 .0
4 30 154 .0 0 .85 295 .39 294 .08 25 .62 7 .8 63.4 20 0 .33 37 .64 8 .0 91 .5 ·----
4A 30 79 .6 0 .85 296 .17 295.49 25 .62 7 .8 63.4 10 0 .17 37 .64 8.0 91 .5 -----
5 18 42 .0 0 .71 297.47 297 .17 4.04 6 .52 5 .2 67.2 8 0 .13 5.44 8 .79 5 .2 90 .8 ---
7 24 70 .7 1.00 299 .57 298 .86 11 .57 18 .69 7 .6 73 .5 9 0 .16 12.48 20 .16 7 .6 78 .6 ---•• 8 42 42 .5 0.40 301 .00 300 .83 78 .79 7 .3 89 .3 6 0 .10 106 .51 8 .9 100 .0 --·-··9 48 206 .7 0.40 300 .80 299 .97 80 .35 7.4 90 .7 28 0.47 108 .62 9 .1 100 .0
25 year storm 100 year storm
Culv ert @ SH 40 18 54 .0 1.00 298.10 297 .56 5.88 9 .50 6 .3 100 .0 9 0 .14 6.98 11 .27 6.4 100 .0
"These values reflect the actual flow for the 18" & 24 " pipes . The design flow for these pipe sizes reflects a 25 % reducti on in pipe area .
(Refer to attached calculation for specific information .)
**Pipe 3 Headwater (for 0 100) = 300 .72 , Top of curb= 302 .71
Bo x 8 Headwater (fo r 0 100) = 307 .68 , Top of curb= 308 .62
Box 9 Headwater (for 0 100) = 306 .09, Top of curb= 308 .62
Travel Time, tT1oo
(sec) (min)
25 0.42
19 0 .32
10 0 .17 --
8 0 .13
9 0 .16
5 0 .08 ---
23 0.38
8 0 .14
City of College Station requirement to Reduce Cross-Sectional Area of 18" & 24" Pipes by 25%
Using Mann ing s Equation from page 48 of the College Station Drainage Policy & Design Standards Manual :
Q = 1.49/n • A • R213
• S 112
Q = Flow Capacity (cfs)
18" Pipe:
Pipe size (inches) = 18
Wetted Perimeter W P. (ft)= 4 .71
Cross-Sectional Area A , (ft2 ) = 1 . 766
Reduced Area A R. (ft2) = 1.325
Hydraulic Radius R = A!WP, (ft)= 0 .375
Reduced Hydr Radius RR = A RMlp. (ft)= 0 .281
Roughness Coefficient n = 0 .014
Friction Slope of Conduit Sr. (ft/ft) = 0 .01
Example Calculation :
Slope Flow Capacity Reduced Flow Capa ci ty % Difference
s Q Or educed O reduced /Q
0 .005 6 .91 4.28 0.619
0 .006 7 .57 4 .69 0.619
0 .007 8 .18 5 .06 0.619
24" Pipe:
Pipe size (inches) = 24
Wetted Perimeter WP. (ft) = 6 .28
Cross-Sectional Area A, (ft2) = 3 .14
Reduced Area A R. (ft2) = 2 .355
Hydraulic Radius R = A!WP, (ft) = 0 .5
Reduced Hydr Radius RR= ARM/p, (ft) = 0 .375
Roughness Coefficient n = 0 .014
Friction Slope of Conduit Sr. (ft/ft) = 0.01
Example Calculation :
Slope Flow Cap acity Reduced Flow Cap aci ty % Difference
s Q O reduce d Oreduce c/Q
0 .005 14.89 9 .22 0.619 ------
0 .006 16.31 10.1 0.619 ------ ----------
0 .007 17.61 10.9 0.619
Conclusion:
Mu ltiply actual Q in 18" & 24" pipes by 1.615 to reflect a 25% reduction in the
cross-sectional area called for on page 47 , paragraph 5 of the College Station
Drainage Policy & Design Standards manual.
Inlet 1103 I 4 .04
J,
Pipe 5 I 4.04 I
J,
Inlet 110 2 I 21 .58
J,
Pipe 4A I 25.62
J,
June Bo x 1
J,
Pipe 4 I 25.62
J,
June Bo x 2
J,
Pipe 3 I 37 .19
J,
Castlegate Subdivision
Section 11 -Pipe Flow Diagram
0 10 (cfs)
From Sect. 10 I
J,
In let 1009 I
J,
Pipe 8 i
J,
ln let1010 I
J,
Pipe 9 I
J,
62 .00
16.79
78 .79
1.56
80 .35
Inlet 1101 I 11 .57 II into Spring Crk I 80.4 II
J,
Pipe 7 I 11 .57 I
Ii Temp Chann el I 37 .2 ii
In le t 1 103 I 5.44
J,
Pipe 5 I 5.44
J,
In let 1102 I 32 .20
J,
Pipe 4 A I 37 .64
J,
Ju ne Box 1
J,
Pipe 4 I 37 .64
J,
Jun e Box 2
J,
Pipe 3 I 50 .12
J,
Castlegate Subdivision
Section 11 -Pipe Flow Diagram
0 100 (cfs)
From Sect. 10 I 83 .59
J,
In let 1009 I 22 .92
J,
Pipe 8 I 106 .51
J,
Inlet 1010 I 2 .11
J,
Pi pe 9 I 10 8.6 2
J,
Inlet 1101 I 12 .4 8 II into Sp ring C rk I 108 .6 II
J,
Pipe 7 I 12.4 8
II Temp Chan nel I 50.1 II
Pipe 3 -10 Yea r Storm
Manning Pipe Cal c ulator
Giv en Input Data :
Shape .......................... .
Solving for .................... .
Diameter ....................... .
Flowrate ....................... .
Slope .......................... .
Manning's n .................... .
Computed Results :
Depth .......................... .
Area .................... · · · · · · · ·
Wetted Area .................... .
Wetted Perimeter ............... .
Perimeter ...................... .
Velocity ....................... .
Hydraulic Radius ............... .
Percent Full ................... .
Full flow Flowrate ............. .
Full flow velocity ............. .
Circular
Depth of Flow
36 .0000 in
37.19 0 0 cfs
0.0045 ft/ft
0 .0140
26.5795 in
7 .0686 ft2
5.5949 ft2
74.4344 in
113.0973 in
6. 6471 fps
10 .8 2 39 in
73.8319 %
41.5467 cfs
5 .8777 fps
Pipe 3 -100 Year Storm
Culvert Calculator
Entered Data:
Shape .......................... .
Number of Barrels .............. .
Solving for .................... .
Chart Number ................... .
Scale Number ................... .
Chart Description .............. .
Scale Description .............. .
Overtopping .................... .
Flowrate ....................... .
Manning ' s n .................... .
Roadway Elevation .............. .
Inlet Elevation ................ .
Outlet Elevation ............... .
Diameter ....................... .
Length ......................... .
Entrance Loss .................. .
Tail water ...................... .
Computed Results:
Headwater ...................... .
Slope .......................... .
Velocity ....................... .
Ca stlegate Su b div i sio n -Sectio n 11
Col l ege Station, Texas
Circular
1
Headwater
1
1
CO NCRET E PI PE CULV ERT; NO BEVELED RING ENTRANCE
SQUARE EDGE ENTRANCE WITH HEADWALL
Off
50 .1200 cfs
0. 0140
302 .7100 ft
293.6600 ft
292.9000 ft
36 .0000 in
167 . 9600 ft
0.0000
5.9400 ft
300.7159 ft Outlet Contro l
0.0045 ft/ft
7.0905 fps
Pipe 4 -10 Year Storm
Manning Pipe Calculator
Given Input Data:
Shape .......................... .
Solvi ng for .................... .
Diameter ....................... .
Flowrate ....................... .
Slope .......................... .
Manning's n .................... .
Computed Results:
Depth .......................... .
Area ........................... .
Wetted Area .................... .
Wetted Perimeter ............... .
Perimeter ...................... .
Velocity ....................... .
Hydraulic Radius ............... .
Percent Full ................... .
Full flow Flowrate ............. .
Full flow velocity ............. .
Circular
Depth of Flow
30.0000 in
25 .6200 cfs
0.0085 ft/ft
0.014 0
19.0193 in
4 .9087 ft2
3.2816 ft2
55.26 20 in
94.2478 in
7. 8072 fps
8.5511 i n
63 .3978 %
35.1148 cfs
7.1535 fps
Pipe 4 -100 Year Storm
Manning Pipe Calculator
Given Input Data:
Shape .......................... .
Solving for .................... .
Diameter ....................... .
Flowrate ....................... .
Slope .......................... .
Manning's n .................... .
Computed Results:
Depth .......................... .
Area ........................... .
Wetted Area .................... .
Wetted Perimeter ............... .
Perimeter ...................... .
Velocity ....................... .
Hydraulic Radius ............... .
Percent Full ................... .
Full flow Flowrate ............. .
Full flow velocity ............. .
Castlegate S ubdi vis ion -Section 11
College Station , Texas
Circular
Depth of Flow
30.0000 in
37.6400 cfs
0.0085 ft/ft
0. 0140
27.4570 in
4 .9087 ft2
4 .7084 ft2
76.5222 in
94.2478 in
7.9942 fps
8.8603 in
91.5233 %
35.1148 cfs
7 .1535 fps
Pipe 4A -10 Year Storm
Manning P i pe Calculator
Given Input Data :
Shape .......................... .
Solving for .................... .
Diameter ....................... .
Flowrate ....................... .
Slope .......................... .
Manning's n .................... .
Computed Results :
Depth .......................... .
Area ........................... .
Wetted Area .................... .
Wetted Perimeter ............... .
Perimeter ...................... .
Velocity ....................... .
Hy draulic Radius ............... .
Percent Full ................... .
Full flow Flowrate ............. .
Full flow velocity ............. .
Circular
Depth of Flow
30 .0000 in
25.6200 cfs
0.0085 ft/ft
0 . 0140
19 .019 3 in
4.9087 ft2
3 .2816 ft2
55.26 2 0 in
94.2478 in
7.8072 fps
8 .55 11 in
63 .3978 %
35.1148 cfs
7.1535 fps
Pipe 4A -100 Year Storm
Manning P i pe Calculator
Given Input Data:
Shape .......................... .
Solving for .................... .
Diameter ....................... .
Flowrate ....................... .
Slope .......................... .
Manning' s n .................... .
Computed Res u lts:
Depth .......................... .
Area ........................... .
Wetted Area .................... .
Wetted Perimeter ............... .
Perimeter ...................... .
Velocity ....................... .
Hydraulic Radius ............... .
Percent Fu ll ................... .
Full flow Flowrate ............. .
Full flow velocity ............. .
Castlegat e S ubd ivision -Section 11
College Station, Texas
Circular
Depth of Flow
30 .0000 in
37 .6400 cfs
0 .0085 ft/ft
0.0140
27.4570 in
4.9087 ft2
4.7084 f t 2
76.5222 in
94.2478 in
7.9942 fps
8.8603 in
91. 5233 %
35 .1148 cfs
7.1535 fps
Pipe 5 -10 Year Storm
Manning Pipe Calculator
Gi v en Input Data :
Shape .......................... .
Solving for .................... .
Diameter ....................... .
Flowrate ....................... .
Slope .......................... .
Manning's n .................... .
Computed Results :
Depth .......................... .
Area ........................... .
Wetted Area .................... .
Wetted Peri meter ............... .
Perimeter ...................... .
Vel o city ....................... .
Hydraulic Radius ............... .
Percent Ful 1 ................... .
Full flow Flowrate ............. .
Full flow velocity ............. .
Circular
Depth of Flow
18 .0000 in
6 .5 2 00 cfs
0. 0071 ft/ft
0.0140
12 .1040 in
1.7671 ft2
1.2637 ft2
34.6125 in
56 .5487 in
5.1593 fps
5.2576 in
67 .2445 %
8 .2189 cfs
4 .6509 fps
Pipe 5 -100 Year Storm
Manning Pipe Calculator
Given Input Data :
Shape .......................... .
Solving for .................... .
Diameter ....................... .
Flowrate ....................... .
Slope .......................... .
Manning' s n .................... .
Computed Results:
Depth .......................... .
Area ........................... .
Wetted Area .................... .
Wetted Perimeter ............... .
Perimeter ...................... .
Velocity ....................... .
Hydraulic Radius ............... .
Percent Full ................... .
Full flow Flowrate ............. .
Full flow velocity ............. .
Ca stlegate S ubdiv i sion -Se c tion 11
Coll ege S tation , Texas
Circular
Depth of Flow
18 .0000 in
8 .7900 cfs
0.0071 ft/ft
0.0140
16.3512 in
1.7671 ft2
1 .6863 ft2
45.4796 in
56.5487 in
5.2126 fps
5 .3393 in
90 .8401 %
8.2189 cfs
4.6509 fps
Pipe 7 -10 Year Storm
Manni n g Pipe Calculator
Given Input Data:
Shape .......................... .
Solving for .................... .
Diameter ....................... .
Flowrate ....................... .
Slope .......................... .
Manning's n .................... .
Computed Results:
Depth .......................... .
Area ........................... .
Wetted Area .................... .
Wetted Peri meter ............... .
Perimeter ...................... .
Velocity ....................... .
Hydraulic Radius ............... .
Percent Full ................... .
Full flow Flowrate ............. .
Full flow veloci ty ............. .
Circular
Depth of Flow
24.0000 in
18.6900 cfs
0 .0100 ft/ft
0 .0140
17.6306 in
3.1416 ft2
2.4736 ft2
49.4209 in
75.3982 in
7.5559 fps
7.2073 in
73.4610 %
2 1.00 65 cfs
6.6866 fps
Pipe 7 -100 Year Storm
Manning Pipe Calculator
Given Input Data:
Shape .......................... .
Solving for .................... .
Diameter ....................... .
Flowrate ....................... .
Slope .......................... .
Manning's n .................... .
Computed Results:
Depth .......................... .
Area ........................... .
Wetted Area .................... .
Wetted Peri meter ............... .
Peri meter ...................... .
Velocity ....................... .
Hydraulic Radius ............... .
Percent Full ................... .
Full flow Flowrate ............. .
Full flow velocity ............. .
Castlegate S ubdivision -Sect i o n 11
College Station, Texas
Circular
Depth of Flow
24.0000 in
20.1600 cfs
0 .0100 ft/ft
0 .0140
18.8545 in
3 .1416 ft2
2 .6476 ft2
52.2906 in
75.3982 in
7 .6144 fps
7 .2911 in
78.5605 %
21.0065 cfs
6.6866 fps
Bo x 8 -10 Year Storm
Mann ing Pipe Calculator
Give n Input Data:
Shape .......................... .
Solving for .................... .
Height ......................... .
Wi dth .......................... .
Flowrate ....................... .
Slope .......................... .
Manning's n .................... .
Computed Results:
Rectangular
Depth of Flow
36.0000 in
48.0000 in
78.7 90 0 cfs
0 .0040 ft/ft
0.0140
Depth . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 . 1644 in
Area ........................... .
Wetted Area .................... .
Wetted Perimeter ............... .
Perimeter ...................... .
Velocity ....................... .
Hydraulic Radius ............... .
Percent Full ................... .
Full flow Flowrate ............. .
Full flow velocity ............. .
Ent ered Data :
Bo x 8 -100 Year Storm
Culvert Calculator
Shape ........................... .
Number of Barrels .............. .
Solving for .................... .
Chart Number ................... .
Scale Number ................... .
Chart Description .............. .
Scale Description .............. .
Overtopping .................... .
Flowrate ....................... .
Manning's n .................... .
Roadway Elevation .............. .
Inlet Elevation ................ .
Outlet Elevation ............... .
Height ......................... .
Width .......................... .
Length ......................... .
Entrance Loss .................. .
Tailwater ...................... .
Computed Results :
Headwater ...................... .
Slope .......................... .
Velocity ....................... .
Castlegate Subdivision -Sec tion 11
College St ation, Texas
12 .0000 ft2
10.7215 ft2
112.3288 in
168 .0000 in
7 .3488 fps
13.7444 in
89.34 55 %
72.6894 cfs
6.0574 fps
Rectangular
1
Headwater
1
1
CONCRETE PIPE CULVERT; NO BEVELED RING ENTRANCE
SQUARE EDGE ENTRANCE WITH HEADWALL
Off
106 .5100 cfs
0.0140
308.6200 ft
301.0000 ft
300.8300 ft
36.0000 in
48.0000 in
42 .5000 ft
0 .0000
5.2600 ft
307.6775 ft Outlet Co nt rol
0.0040 ft/ft
8.8758 fps
Box 9 -10 Year Storm
Manning Pipe Calculator
Gi ven Input Data:
S hape .......................... .
So lving for .................... .
Hei ght ......................... .
Wi dth .......................... .
Flowrate ....................... .
Slope .......................... .
Manning' s n .................... .
Com puted Results:
Depth .......................... .
Area ........................... .
Wetted Area .................... .
Wetted Perimeter ............... .
Perimeter ...................... .
Velocity ....................... .
Hydraulic Radius ............... .
Perce nt Full ................... .
Full flow Flowrate ............. .
Full flow ve locity ............. .
Rect angular
Depth of Flow
36 .0000 in
48.0000 in
80 .3500 cfs
0 .00 40 ft/ft
0 .014 0
32 .6594 in
12.0 000 ft2
10.88 6 5 ft2
113 .3189 in
168 .0000 in
7 .3807 fps
13.8340 in
90.7207 %
72 .6894 cfs
6.05 74 fps
Box 9 -100 Year Storm
Culvert Calculator
En tered Dat a :
Shape .......................... .
Number of Barrels .............. .
Solving for .................... .
Char t Number ................... .
Scale Number ................... .
Chart Description .............. .
Scale Description .............. .
Overtopping .................... .
Flowrate ....................... .
Manning' s n .................... .
Roadway Elevation .............. .
Inlet Eleva tion ................ .
Outlet Elevation ............... .
Height ......................... .
Width .......................... .
Length ......................... .
Entrance Loss .................. .
Tailwater ...................... .
Compute d Results :
Headwater ...................... .
S lope .......................... .
Velocity ....................... .
Ca s tl e gate Subd iv i sio n -Sec tio n 1 1
Col lege S ta tio n, Texa s
Rectangular
1
Headwater
1
1
CON CRETE PIPE CUL VERT; NO BEV ELE D RING ENT RAN CE
SQUARE EDGE ENTRANCE WITH HEADWALL
Off
108.620 0 cfs
0 . 0140
308.6200 ft
300 .80 00 ft
299.9800 ft
36 .0000 in
48 .0000 in
206.7000 ft
0.0000
3.0000 ft
306.0906 ft Outlet Control
0.0040 ft/ft
9 .0 5 17 fps
Future SH 40 Culvert -25 Year Storm
Cul v ert Calculator
Entered Data:
Shape .......................... .
Number of Barrels .............. .
Solving for .................... .
Chart Number ................... .
Scale Number ................... .
Chart Description .............. .
Scale Description .............. .
Ov ertopping .................... .
Flowrate ....................... .
Manning's n .................... .
Roadway Elevation .............. .
Inlet Elevation ................ .
Outlet Elevation ............... .
Diameter ....................... .
Length ......................... .
Entrance Loss .................. .
Tailwater ...................... .
Computed Results :
Headwater ...................... .
Slope .......................... .
Velocity ....................... .
Circular
1
Headwater
1
1
CO NCRETE PIPE CULVERT ; NO BEVELED RING ENTRANCE
SQUARE EDGE ENTRANCE WITH HEADWALL
Off
9.5000 cfs
0.0140
301.6000 ft
298 .1000 ft
297.5600 ft
18.0000 in
54.0000 ft
0.0000
1.5000 ft
300.2477 ft Inlet Contro l
0 .0100 ft/ft
6.2942 fps
Future SH 40 Culvert -100 Year Storm
Culvert Calculator
Entered Data:
Shape .......................... .
Number of Barrels .............. .
Solving for .................... .
Chart Number ................... .
Scale Number ................... .
Chart Description .............. .
Scale Description .............. .
Overtopping .................... .
Flowrate ....................... .
Manning's n .................... .
Roadway Elevation .............. .
Inlet Elevation ................ .
Outlet Elevation ............... .
Diameter ....................... .
Length ......................... .
Entrance Loss .................. .
Tailwater ...................... .
Computed Results:
Headwater ...................... .
Slope .......................... .
Velocity ....................... .
Cast legat e S ubdi v i s i o n -Sect i o n 11
College Station , Texas
Circular
1
Headwater
1
1
CON CRET E PI PE CULVER T ; NO BEVELED RING ENTRAN CE
SQUARE EDGE ENTRANCE WITH HEADWALL
Off
11.2700 cfs
0. 0140
301.6000 ft
298.1000 ft
297 .5600 ft
18 .0000 in
54.0000 ft
0.0000
1.5000 ft
300 .7163 ft Inlet Control
0.0100 ft/ft
6.3775 fps
APPENDIX C
Temporary Drainage Channel Calculations
Temp Channel -10 Year Storm
Channel Calculator
Given Input Data:
Shape .......................... .
Solving for .................... .
Flowrate ....................... .
Slope .......................... .
Manning's n .................... .
Height ......................... .
Bottom width ................... .
Left slope ..................... .
Right slope .................... .
Computed Results:
Depth .......................... .
Velocity ....................... .
Full Flowrate .................. .
Flow area ...................... .
Flow perimeter ................. .
Hydraulic radius ............... .
Top width ...................... .
Area ........................... .
Perimeter ...................... .
Percent full ................... .
Trapezoidal
Depth of Fl ow
37.2000 cfs
0.0050 ft/ft
0 .0350
30 .0000 in
36.0000 in
0 .2500 ft/ft (V/H)
0 .2500 ft/ft (V/H)
18 .0059 in
2.7540 fps
120.7192 cfs
13. 5074 ft2
184.4807 in
10.5435 in
180 .0474 in
32 .5000 ft2
283.3863 in
60.0198 %
Temp Channel -100 Year Storm
Channel Calculator
Given Input Data :
Shape .......................... .
Solving for .................... .
Flowrate ....................... .
Slope .......................... .
Manning' s n .................... .
Height ......................... .
Bottom width ................... .
Left slope ..................... .
Right slope .................... .
Computed Results:
Depth .......................... .
Velocity ....................... .
Full Flowrate .................. .
Flow area ...................... .
Flow perimeter ................. .
Hydraulic radius ............... .
Top width ...................... .
Area ........................... .
Perimeter ...................... .
Percent full ................... .
Castlegate Subdivision -Sec tion 11
College S ta tion , Te xas
Trapezoidal
Depth of Flow
50.1000 cfs
0.0050 ft/ft
0.0350
30 .0 000 in
36.0000 in
0.2500 ft/ft (V/H)
0 .250 0 ft/ft (V/H)
20 .5428 in
2.9719 fps
120 .7192 cfs
16 .8581 ft2
205.4004 in
11 .8187 in
200.3425 in
32.5000 ft2
283.3863 in
68 .4760 %
APPENDIXD
Time of Concentration Calculations
25
Time of Concentration Calculations
R efer to Exhibit Afar flow path used for each calculation.
Drainage Area #10 -8:
Sheet Flow: Flow length= 300' = L
S lope = 1.5%
n = 0. 15, short grass prairie
P2 = 4 .5"
t1 = 0 .007 (0 .15 * 300)0 8
(4.5)05 (0.0 15 )04
t1 = 0 .3 72 hours = 22.3 minutes
Shallow Concentrated Flow: Flow leng th = 365' = L
Slope= 1.0%
Gutter Flow :
Drainage Area #10-9:
Sheet Flow:
For unpaved s urface at 1.0%, Velocity (V) = 1.6 fps (see Fig . 3-1)
~ t1 = 365' I (60*1.6) = 3 .8 minutes
Flow length = 725' = L
S lope = 1%
For paved surface at 1%, Ve lo c ityV=2 .l fps(seeFig.3-1)
t1 = 725' I (60*2. l) = 5 .8 min utes
Tc= 22.3 + 3 .8 + 5.8 = 31.9 minutes
Flow length = 300 ' = L
Slope= 2.6 %
n = 0 .15, short grass prairie
P2 = 4 .5"
t1 = 0 .007 (0.1 5 * 300)0 8
(4 .5)05 (0 .026)04
t1 = 0 .299 hours= 17 .9 minutes
Shallow Concentrated Flow: Flow length = 606' = L
Slope= 0.95 %
For unp aved s ur face at 0 .95%, Velocity (V)= 1.55 fps (see Fig . 3-1)
t1 = 6 0 6' I (60* 1.55) = 6.5 minutes
Gutter Flow: Flow len gth = 50' = L
**assumin g flow in gutter is n egli gible**
T c= 17.9 + 6.5 = 24.4 minutes
Drainage Area #11 -6:
Sheet Flow:
Time of Concentration Calculations, continued
Flow length = 250 ' = L
Slope = 1.3%
n = 0.15, short grass prairie
P2 = 4.5"
ti = 0 .007 (0 .15 * 250)08
(4.5)05 (0.0 13)04
ti = 0.341 hours = 20.4 minutes
Shallow Concentrated Flo w: Flow length = 700 ' = L
Slope= 2.4 %
For unpaved surface at 2.4%, Velocity (V) = 2.7 fps (see Fig . 3-1)
~ ti = 700 ' I (60*2.7) = 4 .3 minutes
T c= 20.4 + 4.3 = 24.7 minutes
.....,
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(210 -Vl -TR -55. Second Ed .. June l98G l
I
20
EXHIBIT A
Post-Development Drainage Area Map
29