HomeMy WebLinkAbout50 Castlegate Section 7 04-18Apr 22 04 10:24a TEXCON ENGINEERING 9797647759
Design-Build &
p. 1
~~
[J\-22-.-0-1
TEX CON Civil Engineering Services
~ct
]0'<95~
O L}-5 \ Office Location : 2900 A Longmire Drive · College Station. Texas . 77845
Mai li ng Address : 1707 Graham Road · College Station, Texas , 77845
Phone : (979) 764-7743 · Fax : (979) 764-7759
Fax Transmittal
To:
I I
Fax:
Phone: Pages: 2-(including cover)
Company:
If yo u d id not receive this co mp lete fax transmittal, please call (979) 764-7743 ····---
Apr 22 04 10:24a TEXCON ENGINEERING 9797647759 p.2
•
A.
Notice of Intent (NOi) for Storm Water Discharges
Associated with Construction Activity under the
TPOES Construction General Perm ft (TXR15000~ J
For t.Qlp comple1 ing IM .,ppticalion, raad the TXR 150000 NOi IRSlluciio ns
(TCEQ -20022·1nsln1el i ~).
TCEQ Office Use Onl)I
TPOES Perm il Number: TXR 15•.:__·:._·.:__·:._"-NO
GIN Number :·:. ... ::__·:_·;_·:_·:._·:_··
No Change.
Name: i:Ll S d .
Custome r Reference Number: CN_..@..,.=.S".JL..J,;.t,...E-.£4"""._1 .......... __
Mailing Address : 4490 Co..7~a:t..,. ... Dr+1~ Cily:.._.......,....,,.......c.:s::""""'''-"on'-'-=-Slate :J!...2;p Code · :?:JEA-S:
Couolry Ma~ing Information (if ocitside U~) Territory. ___ -______ Pos1al Cooe : -
Phone Number: (41.:y) /e'lo -1'2..SP Extension : ______ Fa>t Numbe-r.-. _(_j_J.:l-....J,_t:?_,..:1-D--1 Oii-' ---
E-mail Address :_-----------------------------------------
Type of Ope rator. 0 Individual 0 Sole Proprietorship • D.B.A. JS Partnershi p 0 Corporarion 0 Federal Government
0 State Gover nmenl 0 County Government 0 City Government 0 Othet: _____ -=----....----------
tndependent Opera tor? '6'[ Yes 0 No Number()fEmployees: jJJ 0-20 0 2 1-100 D 101 :250 0 251 ·SOO D 501 or higher
Federal Tax ID: 1lt-tft4fl 3Jo State Franchi se Tax ID Number. ·N(f>... DUNS Number: N/A-
8 . Billing Addres!I> •
Name: WLL~~~~~dt .Li"'es.+u·s, L+J.
c .
M<lilingAddr~~ f..I~ CitY:Colf~q-a-ficnState :~ZipCode 11911-£
Countl)' Mail ing l nformatioll (if <Jutside USll) T errilory: -Counir: ~ -Post al COOe . -
~cimal Form
Also. clescribe lhe Ct>nstruclion activity at this site (do nol rep~t 1he SIC code):
'
Has a storm water pollution prevention p!an been prepared :as speciried in the general ~rmi r (TXR1 50000)? (Z Yes O No
Est imated area cf land disturbed (to the nearest acre): /!?" Is th e ptoject I s ite localed on Indian Country Lands? O Yes IXJ No
Docs th is projed I sit"' di&charge stom1 water into a municipal separ~te ste>rm sewer ~ys~m (MS4)? 0Yes f8l No
If yes, provide lhe name of tho MS4 operalor: _____________________ .....,....-----:::---,----
Provide the name or segment numl>of d lhe wntef bod~ that receives storm wate' rrom this project I site:
D . Ccmt<1c:t -If the TCEO needs additional information regarding this application. who should be a:mtacted ?
Name : W~!~ T i tte:~W\1L..U:>&a.\/\-a...,~µ;.a..X__,...·-....--..-------
Phone Number :§J'i)Z2'ri-}ri:§) Extension : Fall'. ...,:k>er: ('t1"1)G:fl0-Jo4=1
E-mail Addre5s :
E.. Payment lnfonnatlon • Money Order Number. lO 13 Name on Check I Mciney Order:
F. Certification
I oerti(y under pendyollaw lhal this documen1 was prepated under my d~lion or super-.i,.;oA in accordance wilh a syslem designed to assure lflil l qualified
persoonet propB!ly ga~ and avalu ale Ille Information $t.bmittecl. Based on my inquify ol the petSOn OI persaas whomanalje l/>e system. orlhow per sons
d lrecUy respo<>sble lot gathering lhe Worm11tlof1 , the informat;on submitted is, lo the best of my knowledge and beli ~r. true . accUtate, ;:ind complete. 1 am
;;iware lhere an. signir.canl pe.iahie$ tor submitting false inlomlatlon. including the possib~ily of tine end Imprisonment for knowing vioralions .
Con:.truction Site Ope,ator:
Prefix: me . First: Walli CL Middle :
Last Tu,1\LlpS _s~~Kf::X: T itle : Ma.&t\21-U:----.---------
~gnatura : ~.L&c.r ~iiiC... ~ Date: i.//J;;,/o</
11 you have queshons on how lo fill oul th is f<Km °"about the slonn wale< "rogr;,n:p;:;;;a conlaCl us .a l (512) 239-'1671 .
Individua ls a re en lilted to request anO review !heir personal information that the agencv oalhers on its'°''""· They mav also h.,~e anv errors in the ir inlorm slion
co rrecied . To review s:vr;ti in.lorrnaion. conlac! us al (512) 239-3282 .
The completed NOi mu !I be mailed to the following address. Use the a!lactied document lo submit the $100
applie<it i of\ lee. Pluali'e note lhat the NOi end application fee ar e submitted separatefr to <lilferent addresses .
----·------------
Texas Commission on Envi ronmental Quality
Storm Water & Gener.a l Permits Team; MC. 228
P.O. Box 13087
Austi n , Texa s 78711-3087
---------------····----
OEEE .13r~3S~"l dH
----------·-···--... -----·--·
DEVELOPMENT PERMIT
PERMIT NO. 04-188 (f ~ Project: CASTELGATE SUBDIVISION SECTION 7
COLLlC.l STATION FOR AREAS INSIDE THE SPECIAL FLOOD HAZARD AREA
RE: CHAPTER 13 OF THE COLLEGE STATION CITY CODE
SITE LEGAL DESCRIPTION:
Castlegate Subdivision Section 7
All Lots
DATE OF ISSUE: 05/21/04
OWNER:
Greens Prairie Investors , Ltd .
4490 Castlegate Drive
College Station, Texas 77845
TYPE OF DEVELOPMENT:
SPECIAL CONDITIONS:
SITE ADDRESS:
2270 Green's Prairie Road
DRAINAGE BASIN:
Spring Creek
VALID FOR 12 MONTHS
CONTRACTOR:
Full Development Permit
All construction must be in compliance with the approved construction plans
All trees required to be protected as part of the landscape plan must be completely barricaded in accordance with Section
7 .5.E., Landscape/Streetscape Plan Requirements of the City's Unified Development Ordinance , prior to any operations of
this permit. The cleaning of equipment or materials within the drip line of any tree or group of trees that are protected and
required to remain is strictly prohibited . The disposal of any waste material such as, but not limited to, paint, oil , solvents,
asphalt, concrete , mortar, or other harmfu) liquids or materials within the drip line of any tree required to remain is also
prohibited.
TCEQ PHASE II RULES IN EFFECT
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 .
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 th is permit for development of an area inside 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 .
Administrator/Representative
d..r~
Date
0 :5'-,z y_; [} t
Owner/AgenUContractor Date
TEXCON GENERAL CONTRACTORS 07 -May -04
ENGINEER'S COST ESTIMATE
CASTLEGATE SUBDIVISION
COLLEGE STATION, TEXAS ·
SECTION 7 -24 LOTS
Item Estimated Unit Estimated
No . Description Quantity Price Cost
Sitework
Mobilization/Layout 1.0 LS $10 ,000 .00 $10,000
2 Site Preparation 3 .1 AC $3 ,5 00 .00 $10,85 0
3 Sed iment & Erosion Control 1.0 LS $5,000 .00 $5,000
4 Topsoil Stripping & Replacement 1 ,000 CY $4 .50 $4,50 0
5 Excavation 3,200 CY $3 .50 $11,2 00
6 Lime Stabilized Subgrade 8,660 SY $3 .25 $28, 145
7 Concrete Curb & Gutter 5 ,010 LF $8.00 $40,080
8 Remove Existing Concrete Curb & Gutter 112 LF $6 .00 $672
9 Base Material -6" depth 6 ,665 SY $6 .00 $39,990
10 Asphalt Paving -1 1 /2" depth 6 ,665 SY $5 .00 $33,325
11 Concrete Paving with Brick Pavers 1,425 SF $9 .00 $12,825
12 Concrete Apron 1,360 SF $5 .50 $7 ,480
13 Landscape Sleeves 60 LF $8 .00 $480
Subtotal $204,547
Storm Drainage
14 Drainage Pipe -18 " RCP -structural 28 LF $36 .00 $1,008
15 Drainage Pipe -24 " RCP -non-structural 113 LF $36 .00 $4 ,068
16 Drainage Pipe -27'' RCP -non-structural 270 LF $40 .00 $10,800
17 Drainage Pipe -27" RCP -structural 187 LF $48 .00 $8,976
18 Drainage Pipe -30" RCP -non-structural 210 LF $46 .00 $9,660
19 Headwall/wingwalls -30" RCP EA $2,500 .00 $2,500
20 Inlets 5' wide EA $2,600 .00 $2 ,600
21 Inlets 10' wide 4 EA $3,200 .00 $12 ,800
22 Inlets 15' wide 1 EA $3,600 .00 $3 ,600
23 Remove 24" RCP Stub 6 LF $15 .00 $90
24 Tie into Existing Junction Box EA $450 .00 $450
Subtotal $56,552
Water Lines
25 8" Water PVC CL200 (C900) non -struct 2,152 LF $24 .00 $51 ,648
26 8" Water PVC CL200 (C900) structural 34 LF $30 .00 $1,020
27 Gate Valves -8" 4 EA $600 .00 $2,400
28 M.J. Tees -8" 1 EA $400 .00 $400
29 M.J. Tees -8" x 6" 3 EA $300.00 $900
30 M.J. Tap Tees -8" x 3" 1 EA $300 .00 $300
31 M.J . Bend -8" 11 .25 deg . 6 EA $300.00 $1,800
32 M.J. Bend -8" 22.5 deg. 4 EA $450.00 $1 ,800
33 M .J . Bend -8" 45 deg. 4 EA $500.00 $2 ,000
34 1" SS Wa ter Service 5 EA $600.00 $3,000
35 1" LS Wate r Service 4 EA $700 .00 $2,800
36 1 1/2" SS Wate r Service 2 EA $650.00 $1 ,300
37 1 1 /2" LS Water Service 6 EA $750 .00 $4 ,500
38 2" Blow off Assembly 1 EA $450.00 $450
39 Fire Hydrant Assembly w/ ex te nsio n 3 EA $2,500.00 $7 ,500
40 Connect to ex istin g line EA $350.00 $350
Subtotal $82, 168
Sanitary Sewer Lines
41 6" SOR 26 Pipe -struct; avg depth <8' 341 LF $26 .00 $8 ,866
42 6" SOR 26 Pipe -non-str; avg depth <8' 461 LF $18 .00 $8,298
43 6" SOR 26 Pipe -struct ; avg depth 8'-10' 348-LF $28.00 $9,744
44 6" SOR 26 Pipe -non-str; avg depth 8'-10' 128 LF $20 .00 $2,560
45 6" SOR 26 Pipe -non-str; avg depth 10'-12' 330 LF $24 .00 $1 ,920
46 6" SOR 26 Pipe -non-str; avg depth 12'-14' 150 LF $28.00 $4 ,200
47 8" SOR 26 Pipe -non-str; avg depth 8'-10 ' 165 LF $22.00 $3 ,630
48 6" ASTM -02241-struct; avg depth 8'-1 O' 20 LF $28 .00 $560
49 Sewer Services 14 EA $700.00 $9 ,800
50 Manholes -average depth <8' 3 EA $2,200 .00 $6 ,600
51 Manholes -average depth 8'-10' 3 EA $2,400 .00 $7 ,200
52 Manholes -average depth 10'-12' EA $2,600 .00 $2 ,600
53 Manholes -average depth 12'-14' EA $2 ,800.00 $2 ,800
54 Connect to existing manhole EA $750 .00 $750
55 Manhole Drop Connection EA $750.00 $750
Subtotal $76,278
Total Sitework $204,547
Total Storm Drainage $56,552
Total Water $82,168
Total Sanitary Sewer 76 278
TOTAL CONSTRUCTION $419,545
P;ige 2 o f 2
(Check one)
FOR OFFIC E USE ONLY
P&Z Case No .: OJ-1 l Q
Date Submitted : ll-!) & -o<j
FINAL PLAT APPLICATION
0 Replat 0 Amending
($300 .00)
[if' Final
($400 .00)
0 Vacating
($400 .00) . ($600 .00)*
*Includes public hea ring fe e
The following items must be submitted by an established filing deadline date for P&Z Commission consideration.
MINIMUM SUBMITTAL REQUIREMENTS:·
CB"' Filing Fee (see above) NOTE: Multiple Sheets -$55 .00 .per add itional sheet
Variance Request to Subdivision Regulations -$100 (if applicable)
Development Permit Application Fee of $200 .00 (if applicable).f P/ttD u.J/c,~~ FLAN .5uB't11TTPL ~ Infrastructure Inspection Fee of $600.00 (applicable if any public infrastnkt~re is being constructed)
~ Application completed in full.
[I;}" Thirteen (13) folded copies of plat. (A signed mylar original must be submitted after staff review .)
0 One (1) copy of the approved Preliminary Plat and/or one (1) Master Plan (if applicable).
[g"" Paid tax certificates from City of College Station, Brazos County and College Station l.S .D.
[9--" A copy of the attached checklist with all items checked off or a brief explanation as to why they are not.
g-· Two (2) copies of public infrastructure plans associated with this plat (if applicable).
El Parkland Dedication requirement approved by the Parks & Recreation Board, please provide proof of
approval (if applicable). t VS>
NAME OF SUBDIVISION G.t~±lt:-!]a±e Su.bd.1\11~'tm -Sed'm J
SPECIFIED LOCATION OF PROPOSED SUBDIVISION (Lot & Block) 1Ve:Jof $H= (p D"1 trrfer'lsPmirie~.
APPLICANT/PROJECT MANAGER'S INFORMATION (Primary Contact for the Project):
Name b(iex¥z:fr~r\e ~''f~-i;Drs, Ltd EiMafr Wa.1\a.c.R. 13u~I Up$
Street Address l}:MO UtS.tlwj<L:.:tk Dr l ~
Zip Code 11'i>'J ~ City (ol\.9e ;ta:h'an state_T~'i--::.__ __ _
Phone Number Lq1t() (ifQ ... ]1.--5D Fax Number .....J(H:/~J ......... q4)......,1£l:......L.>£..O___.-/L-"!::0--1f......:...I __ _
CURRENT PROPERTY OWNER'S INFORMATION: (till owners must be identified. Please attach an
additional sheet, if necessary)
Name taViiiYlS Wa.,( v--\ G :GJv~ior~, ltJ ·
Street Address 4:410 Ov1~au Tu\ \tf..
E-Mail ------------
City Co\\eae $tCL1i th1 state _TI~----Zip code ~71:>1f S:
Phone NumbJ; (q1q) (tfiO-]~() Fax Number [q7q){o10 -LOL/{
ARCHITECT OR ENGINEER'S INFORMATION :
Name Joe ~\tl., r .-e I -lexcon
Street Address \JOI htca.bavn R.cxad
E-Mail joesc1u ltr.@±eX.con .ne..t
C ity Co\ \eae 9:di oY\ state __ :Ii~· ___ Zip Code Jlf*S-
Phon e Numberl 0{14)Jb4-114~ Fa x Number {j1q)7flt-J15i
1-Aug-02 1 o f 5
fRt v'A-1E 5TRE.£r R..o. W.
Acreage Total Property 31.014-Total# Of Lots Z-4-R-0-W Acreage 3 -0S
Existing Use : \JAflWlt Proposed Use : :$1~6jlt <fa,ro (~ (t''iat:fmb"&(
Number Of Lots By Zoning District 24-I ..EI2.J2 I __ __I __
Average Acreage Of Each Residential Lot By Zoning District:
I O.i>l\-1 PDD
FloodplainAcreage_~0~~~x~·~~~~-------------------------
I ----I --
A Statement Addressing Any Differences Between The Final Plat And Approved Master Development Plan
And/Or Preliminary Plat (If Applicable):
A
Requested Variances To Subdivision Regulations & Reason For Same : fDD 1:vni«}
Reques~dOve~~ePa~cipation :_n_o_~~---------------------~
Total Linear Footage of
Proposed Public:
Parkland Dedication due prior to filing the Final Plat:
ACREAGE:
2342..1
Streets # of acres to be dedicated + $ --development fee
Sidewalks
\ G\14 1
Sanitary Sewer Lines
~·.a.a' L---t.k:..J Water Lines
Channels
~l'IA1"€-/Puei01C..
2-w'/m 1 Storm Sewers
' Bike Lanes I Paths
--# 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.
d~dl~
Signature and Tit]; ~ Date
1-Aug-0 2 2 o f 5
SUPPLEMENTAL DEVELOPMENT PERMIT INFORMATION
Application is hereby rl2::qe ~r ~e, follo~ing._.developnrent specifiq site/v.:aterway alter9tion!-r , J~\:J (+./'5 (.,,..... "' ..... -\-cu-\;-... ~ a..-..A -{2 ~f;....-... ~< .........
ACKNOWLEDGMENTS:
~ ~ c{i~ p_ 5 _Of\:
I, ~ .~design engineer/oWAef, 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 Code . . W, P· Ut-
Property Owner(s) .COR~ ..... ;· .... t ~
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 .
Engineer () c 1 ~ 1---~~~,~~''' Date jQi<d~ V-.kch-. ..,~ ,#"-<. ..... i··.:1'"'1 '•
C. I, r , certify that the alterati~s :Qt d pnie~t. \)Vered by this permit shall not diminish the flood-
carrying capacity of the waterway ~~j!?]DJD9 .....•. ~ms.~ this permitted site and that such alterations or
development are consistent with reql1~~~-~f.!~.~h.~ College Station City Code, Chapter 13 concerning
''f ~o ·.'9~ rr,,_O,.• !ll JI encro ments of flpy:y and of ~~wayEf9BS9S· J $1
' f(~~···.J~!S TE.~ .. ·~&~"' fr--C 3 ~c) ~ ----4ll'..J-:------"------¥----i..::S~, .:11 .. +•··· ~ .:I' ------------------\ 1 ·_1 _~.:'!.I r;.."' D t \:-":.; . .r>i°""~"" a e
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 shal! 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 of 5
l
Drainage Report
for
Castlegate Subdivision -Section 7
College Station, Texas
April 2004
Developer:
Greens Prairie Investors, Ltd.
By Greens Prairie Associates, LLC
4490 Castlegate Drive
College Station, Texas 77845
(979) 690-7250
Prepared By:
TEXCON General Contractors
1707 Graham Road
College Station , Tex as 77845
(9 7 9 ) 7 64-77 43
CERTIFICATION
I certify that this report for the drainage design for the Castlegate Subdivision -Section 7, was
prepared by me in accordance with the provisions of the City of College Station Drainage
Policy and Design Standards for the owners hereof.
Ginge
TABLE OF CONTENTS
DRAINAGE REPORT
CASTLEGATE SUBDIVISION -SECTION 7
CERTIFICATION .................................................................................................................................................................. 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
Time of Concentration Equations & Calculations
APPENDIX B ........................................................................................................................................................................ 10
Storm Sewer Inlet Design Calculations
APPENDIX C ........................................................................................................................................................................ 13
Storm Sewer Pipe Design Calculations
EXHIBIT A ............................................................................................................................................................................ 24
Post-Development Drainage Area Map
LIST OFT ABLES
TABLE 1 -Rainfall Intensity Calculations .......................................................................................... 4
TABLE 2 -Time of Concentration (tc) Equations .............................................................................. 4
TABLE 3 -Post-Development Runoff Information ............. '. .............................................................. 5
INTRODUCTION
DRAINAGE REPORT
CASTLEGATE SUBDIVISION -SECTION 7
The purpose of this report is to provid e the hydrolo gical effects of the construction of th e
Castlegate Subdivision -Section 7, and to verify that the proposed storm drainage system
meets th e requirem e nts set forth by th e C ity of College Statio n Drainage Poli cy a nd Des ign
Standards .
GENERAL LOCATION AND DESCRIPTION
The project is located on a portion of a 111.46 acre tract located west of State Highway 6 a long
the north side of Greens Prairie Road in College Station, Texas . This report addresses Section
,7 of this subdivision , which is made up of 31.09 acres . Section 7 is lo cated adjacent to
Castlegate Section 5 along Castlegate Drive . The site is predominantly wooded. T he ex isting
ground elevations range from elevation 304 to elevation 336 . The gen eral loc ation of th e
project site is shown on the vi cinity map in Exhibit A.
FLOOD HAZARD INFORMATION
The project site is located in the Spring Creek branch of the Lick Creek Drainage Basin. Most
of the proposed developed area of the site is located 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 February 9, 2000, panel number
48041C0205-D. A portion of this development is in Zone AE, a Special Flood Hazard Area
inundated by the 100-year flood. This area is shown on Exhibit A as the 100-year floodplain
limit. Also shown on this exhibit are the floodway limits as determined by the Castlegate
Floodplain Analysis Report which was previously submitted. The Flood Hazard Area along
Spring Creek Tributary A2B within this development has been designated as Greenway Area,
which will have no development and it will be left in its current condition . The Flood Hazard
Area along Spring Creek Tributary A2A encroaches on four proposed lots , as shown on Exhibit
A. A drainage easement has been created along the rear of these lots to prevent de ve lopment in
the Flood Hazard Area. Also, a minimum finished floor elevation (FF) is required for these
lots, which is a minimum of 3 feet above the Base Flood Elevation (BFE).
DEVELOPMENT DRAINAGE PATTERNS
Prior to development , the storm water runoff for Section 7 flows in two different direction s. A
portion of the runoff flows in a north eas terly direction until it enters a Tributar y A2B of Sprin g
Creek . T he remaind er of th e runo ff from this site flows in a northwesterly dir ec tion int o
Tri but ary A2A of Spring Creek . Ultimate ly, both trib ut ari es flow in to Sprin g C reek and th e n
north to th e prop osed reg ion a l de te nti o n fac ilit y. Refe r to the v ic init y map in Ex hibit A for the
location o f th is reg ional dete ntion fac ilit y.
DR A I NAGE DESIGN C RIT E RI A
T he d es ign pa ram e te rs fo r th e s to rm sewe r ana lys is a re as fo llo ws:
• Th e Ra ti o na l Method is ut ili7.e d to dete rmin e pea k s tor m wa te r run off rates for th e s torm
sewer des ig n and dete nti o n fa c i lit y a na lys is.
• Design Storm Frequency
Storm sewer s ystem
• Runoff Coefficients
Pre-development
10 and .100-year storm events
Post-development (singl e family residential)
c = 0 .30
c = 0 .50
• Rain fa ll Intensity equations and va lu e s for Braz os County can be found in T abl e 1.
• Time o f Concentration, tc -Calculations are b ased on th e m ethod found in the TR-55
publication. Re fe r to T able 2 for th e equations and Appendi x A for ca lcul ation s. The
runoff flow path used for calculating the post-development time of concentra tion for
Drainag e Area 3 is shown in Exhibit A. The remainder of the drainag e areas us e a
minimum tc of 10 minutes to determine the rainfall intensity values.
STORM WATER RUNOFF DETERMINATION
The peak runoff values were determined in accordance with the criteri a present ed in the
previous section for the 5 , 10 , 25 , 50 , and 100-year storm events . The drainage ar eas for t he
post-development condition are shown on Exhibit A . Post-development runo ff conditions for
the storm sewer design are summarized in Table 3.
TABLE 1 -Rainfall Intensity Calculations
Rainfall Intensity Values (in/hr)
Storm tc=
Event 10 min
l5 7 .693
110 8.635
lz5 9.861
150 11 .148
1100 11.639
Brazos County:
51'.',ear storm 10 l'.',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)
tc = U(V*60)
tc = Time of concentration (min)
L = Length (ft)
V =Velocity (ft/sec)
25 l'.',ear storm 50 l'.',ear storm 100 l'.',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 Hiqhwal'.',S and Public Transportation Hl'.',draulic Manual , page 2-16)
TABLE 2 -Time of Concentration (tc ) E quation s
The ti me of co ncentration was de termin ed using me thods found in TR-55, "Urba n
Hy drology/or Small Wat ers heds . " Tli e eq uatio ns are asfol/0 1vs:
Time or Conce ntration :
For S hee t Fl ow: T I
Tc == T r(s ht·c r fl ow )+ T 1(ro 11 n·11 1r a l l't l shl'l'f tlm')
w he re: T 1 =T rav e l Time , 111111u te s
0.007 (11 L)0 x
(P 2)
05 s0
A w he re: T , =travel tim e . hour s
n =Manning's roughness coefficient
L = flow length, feet
· P2 = 2-year , 24-hour rainfall = 4 .5"
s = land slope, ft /ft
For S ha ll ow Con ce ntrated F low: T 1 =L I (60*V)
R efer to Appendix A for calcul at ions.
w h ere : T 1 = travel time , minutes
V =Velocity , fps (See Fi g 3 -1 , App. E)
L = flow length , feet
T AB LE 3 -Po st-Deve lopment Runo ff Info r m ati on
A c le
5 year storm 10 year s torm 25 year storm 50 yea r s t orm 100 year s to r m
Area# Is O s 110 0 1"0 l2s 0 2s lso O so 1100 0 100
(acres) (mi n) (in/hr) (cfs ) (in/hr) (cfs) (in/hr) (cfs) (in/hr) (cfs) (in/hr) (cfs)
1 0.11 0 .5 10 7.693 0.42 8 .635 0.47 9 .861 0.54 11 .148 0.61 11 .6 39 0 .64
2 1.61 0 .5 10 7.693 6 .19 8 .635 6 .95 9.861 7.94 11 .148 8 .97 11 .639 9 .37
3 2.42 0 .5 14 .6 6.462 7 .82 7 .289 8 .82 8 .341 10 .09 9.448 11.43 9.858 11 .93
4 2 .04 0.5 10 7.693 7 .85 8 .635 8 .81 9.861 10 .06 11 .148 11 .37 11 .639 11.87
5 0.49 0.5 10 7 .693 1.88 8 .635 2.1 2 9.861 2.42 11 .148 2.73 11 .639 2 .85
6 0 .21 0 .5 10 7 .693 0 .81 8.635 0 .91 9 .861 1.04 11 .148 1.17 11.639 1 .22
7 0 .11 0 .5 10 7.693 0 .42 8 .635 0.47 9 .861 0 .54 11 .148 0 .61 11 .639 0 .64
8 0 .52 0 .5 10 7.693 2.00 8 .635 2 .24 9 .861 2.56 11.148 2 .90 11 .639 3.03
9 2 .47 0 .5 10 7.693 9 .50 8 .635 10.66 9 .861 12 .18 11 .148 13 .77 11 .639 14 .37
10 0 .57 0 .5 10 7.693 2 .19 8.635 2.46 9.861 2 .81 11 .148 3.18 11 .639 3 .32
DETENTIO N FAC I L ITY DE SIGN
The detention facility hand ling th e runoff from this site is a regional facility designed by LJ A
Engineering & Surveying, Inc. A lso, a detention pond was constructed upstream of Castlegate
Drive to reduce the peak fl ow res ulting from the Castlegate development. The detention
faci lity is located adjacent to Spring Creek prior to S p ring Creek entering the State Highway 6
right-of-way.
STO RM SEWER DE SI GN
The storm sewer piping for this project has been selected to be Reinforced Concrete Pipe
(RCP) meeting the requirements of ASTM C-76, Class III pipe meeting the requirements of
ASTM C-789 . The curb inlets and junction boxes wi ll be cast-in-place concrete.
Appendix B presents a summary of th e storm sewer in let d es ign param e te rs and calculations .
The inl ets we re d es ig ned based on a 10 -yea r desi g n s tom1 . As p e r Co ll ege Stat ion g uid e lin es,
the cap acit ies of inl e ts in sump were red uced b y l 0% to a ll ow fo r c logg in g.
Inl e ts fo r the res id e nti a l s tr eets w e re loca ted to mainta in a gu tt e r n ow dep th of 5" o r less. T hi s
des ig n dept h w ill prevent th e s pread of wa te r from reachin g th e crown of th e road fo r th e 10 -
ye ar s torm eve nt. Refer to Appe ndi x B for a s u mma ry of th e g utt e r n ow d e pth s. The run o ff
intercept ed b y th e proposed s to1111 sewe r inl e ts was ca lculat e d us in g th e following eq uations.
T he depth of n ow in th e g ut ter was d e te rmin e d b y us in g th e Stra ig h t Crow n F low eq ua ti o n .
T he n ow intercepted b y In lets 700 , 70 I , 704 & 705 wa s ca lc ulated b y usin g th e Ca p aci t y of
Inl e ts On Grade equa ti o n . Th ese e qu a ti o ns and res ul tin g data a rc s umm a ri zed in A pp e ndi x B .
·'
The capacities for the inlets in sump (Inlets 702 & 703) were calculated using the Inlets in
Sumps, Weir Flow equation with a maximum allow.able depth of 7" (5" gutter flow plus 2"
gutter depression). These equations and the resulting data are also summarized in App e ndix B .
The area between the right-of-way and the curb line of the streets will be graded as necessary to
provide a minimum of 6" of freeboard above the curb line . This will ensure that the runoff
from the 100-year storm event will remain within the street right-of-way.
Appendix C presents a summary of th e stonn 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 ho w this
was achieved is shown in Appendix C as well. The pipes for the storm sewer system were
designed based on the 10-year storm event, and they will also pass the 100-year storm event.
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 maximum flow in the storm sewer pipe system
will occur in Pipe No. 6. The maximum velocity for the pipe system in this development will
be 9.8 feet per second and will occur in Pipe No . 1. Appendix C contains a summary of the
pipe calculations as well as flow diagrams mapping the flows through the storm sewer system
for the 10 ·and 100-year events.
CONCLUSIONS
The construction of this project will increase the storm water runoff from this site. The
proposed storm sewer system should adequately control the runoff and release it into existing
drainages or the existing storm sewer system along Castlegate Drive. 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. The regional
detention facility should adequately control the peak post-development runoff so that it will not
have any impact on the properties downstream of the Crowley Tract.
APPENDIX A
Time of Concentration Equations & Calculations
7
Post-Development
Time of Concentration Calculations
Refer to Exhibit B for flow paths us ed for calculations.
Drainage Area 3:
Sh eet Flow: Flow length = 100' = L
Slope = 2.2 %
n = 0 .15 , short grass prairie
P2 = 4.5 "
tt = 0.007 (0 .15 * 100)°"8
( 4.5)0·5 (0.022)0.4
t1 =0.133 hours= 8.0 minutes
Shallow Concentrated Flow : Flow length= 220' = L
Slope = 2 .6%
Flow along Pavement:
For unpaved surface at 2.6%, Velocity (V) = 2.6 fps (see Fig . 3-1)
t1 = 220 ' I ( 60*2 .6) = 1.4 minutes
Flow length, L@ Slope , Sand Velocity, V
Using Figure 3-1 for paved surface to find V
L = 300 ' @ 1.25%, V = 2.25 fps
L = 265 ' @2.0%, V = 2 .9 fps
L = 225'@ 1.5%, V = 2 .5 fps
= 300/(60*2.25) + 265/(60*2 .9) = 225/(60*2.5) = 5 .2 minutes
Tc= 8.0 + 1.4 + 5.2 = 14.6 minutes
+-'
'+--+-'
'+-
CIJ a.
0 .-
Cll
CIJ
Cll
L :::s
0 u
L
cu
.µ .,
3
3 .2
.50
.20 -
.10
.06
.04
. 02 -
.01 -
.005
I
1
J
·-~
I
' I
I
~
'
j
' ' . ' .
b
~q,,L.-l::i'
"' q,, ~ ~ .::::> Q.
J
I j
I
J
I
2
r
j
I
4
IJ
IJ
I
' r
!J
I
6
I
I
r
"
..
'
'
Ave r age ve l ocity , f t/sec
'
. . . .
' I
I
I
r
I I
10
. . .
6
Fil(U"' :\-1.-Averal(e vc lo<:i t ieo for c;ti ma t i nl( l rJvd t ime for ;hallow co n <:e nlrated n ow .
(2l0-Vl-TR -55 . Seco nd Ed .. June 198Gl
I
20
.\
.i
i
l '• <
' '
APPENDIXB
Storm Sewer Inlet Design Calculations
10
Castlegate Subdivi s ion
Section 7, Castlegate Drive
Inlet Length Calculations
Inlets In Sump
Inlet If Length & Type Flow from A
Area# (acres)
702 10' 4 2.04 -------5 0 .49
703 10' 3 2.42 ·-6 0 .21
c
0.50 ---0.50
0.50
0.50
10year1torm
a,. O....,"w a. .... Or ..... 1n Y11_._,
(efs) (efs) from Inlet I (els) (els) (ft) (In)
8.81 8.81 9 .89 0.350 4.20
2 .12 2 .12 2.33 0.205 2.48
10.45 10.45 11 .49 0.373 4 .47
0.91 0.91 1.00 0.149 1.79
Inlets On Grade 10yearstorm
lnl el 11
700
701
705
70J
L•ngth & Type Flow from y,. a,_,_ a.-a...... a....-
Area# (ft) (in) (ft) (efs) (els) (els)
10' 2 0.375 4 .51 0 .67 8,68 0.27 6 ,6 8
10' 1 0.370 4 .44 0.66 8.63 0.06 8.63 --5' 10 0 .280 3.36 0 .56 2.66 -0 .42 2.46
15' 9 0.395 4 .74 0 .69 10.32 0.35 10.32
Transverse (C rown ) slope (fl/fl ) = 0 .038 lnlel 704 (51 ' streel width)= 0 .030
Straight Crown Flow !S olved to find actual depth of flow. y):
a= o .56 • (zin) • s "' · y"'"' y • {Q / co .ss • (z/n) • s"'n"'
n = Roughness Coefficient =
z = Rec iprocal of crown slope =
S = Streel/Gutter Slope (IUfl)
y = Dep1h of flow al 1nle< (ll)
Capacity of Inlets on grade :
O e = 0 .7 • [11(H 1 • H2)) • (H ,51 '-H2
512 )
Oc =Flow capacity of inle1 '(cfs)
H, =a • y
0 .018
26 lnlel 704 (51' streel width)= 33
H 2 =a = gu11e r depression (r Standard: 4 " Recessed)
y = Dep<h of flow 1n approach guuer (fl )
O....,"w a...-
(els) ..,.,,_. (di)
0.27
0.06
0.06 701 0.00
0,35
100 year storm
L11""~" . Ltt...-.t a,,. O....,"w a. .... o,.,..., .... y,,.
(ft) (ft) (els) (els)
9.00 10 11.87
2 .85
9.35 10 14 ,08
1.22
•Ulllng-,._•r•o.583'
a....-Q 1t·T .... y,,.
(cf•) (els) (ft) (In)
6.68 6.95 0 .420 5.04
6.83 6 ,69 0 ,414 4,97
2 .46 2 .46 0 .373 4.47
10.32 10.66 0.442 5 .30
Inlets In sumps. Weir Flow ;
L • Q I (3 • y:112) «> y • (Q I 3L)213
L = Length of Inlet opening (ft)
Q = Flow at inlet (els)
y = total depth of flow on Inlet (ft)
max y for inlet in sump = 1• = 0 .583'
tromlnlet# (els) (efs) (ft)
11 .87 13.06 0.663
2 .85 3.14
14 .08 15.49 0.680
1.22 1.34
100 year storm
a.,. .... a..,...., a...... a....-
(ft) (els) (els) (di)
0.71 7.13 2.24 7.13
0.71 7.07 1.95 7.07
0.61 3.04 0.28 3.04
0.74 11 .04 3.34 11.04
(In )
7.96
8. 16
O....,"w a.,... .... a.... ... a, ... fee .. s i_. ...
(els) from !Net• (cf•) ids) (di) (ft/fl) (ft)
2.24 7.13 9.37 0.0134 10
1.95 7.07 9.02 O.Q134 10
1.95 701 2.23 3.04 5.27 0.0060 5
3.34 11.04 14 .37 0.0150 15
Castlegate Subdivision -Section 7
Dept h of Flow in Street Gutter
10-y ear s torm
Gutter A c Slope 0 10 Y10-ac tual
Location (acres) (ft/ft) (cfs) (ft) (in)
81 1.55 0 .50 0 .01 34 6 .69 0 .370 4.44
-·-·------
82 1.61 0 .50 0 .0134 6 .95 0 .375 4 .51 ---------------------------·-----
C1 1.65 0 .50 0 .0102 7 .12 0.399 4.79
~. . -----------·-·-· ·-------------------r.
a. al ~ g ~ -~
_J Ci) ~
~
~ 0 ~ c U1 r. ~ I u c + -~
w~
C2 0.27 0 .50 ---------·------
01 0 .21 0 .50 -------
02 2 .42 0 .50 ------------
03 0 .39 0.5
04 2 .04 0 .50
E1 0.57 0 .50
A1 2.47 0 .5
A2 0 .52 0 .5 0
T ransverse (Crown) slope (ft/ft)
for loop street= 0.0380
e ntra nce = 0.030 0
0 .0102 1.17 0 .202 2.43 -------------
0 .0080 0 .91 0 .193 2.31
0 .0150 8 .82 0.402 4 .82
0.0080 1.68 0 .243 2.92
0 .0 150 8.81 0.402 4 .82
0 .0080 2.46 0 .280 3 .36
0.01 50 10 .66 0.395 4 .74
0 .01 50 2 .25 0 .220 2 .64
Stra ight Crown Flow (Solved to find actual depth of flow in gutter, y):
Q = 0 .56 * (z/n) * S112 * y813 ¢ y ={QI (0 .56 * (z/n) * S 112]}318
n = Roug hn ess Coefficie nt = 0 .018
S = Street/Gutte r Slope (ft/ft)
y = Depth of flo w at inl et (ft)
z = Reciproca l of crow n slo pe :
for loo p street= 26
entrance = 33
100 -y ear storm
0 100 Y100
(cfs) (ft) (i n )
9.02 0.414 4 .97 -----·-----
9 .37 0.420 5 .04 -------
9.60 0 .446 5 .35 ---·--
1.57 0 .226 2.71
---·-·
1.22 0 .2 15 2.59 -----
11.93 0.450 5.40
·-------
2 .27 0.272 3 .26 ---------
11 .87 0 .449 5.39 ----------
3 .32 0.313 3 .76
14 .37 0.442 5 .30
3 .03 0.246 2 .96 ·---. ----
APPENDIXC
Storm Sewer Pipe Design Calculations
Castlegate Subdivision
Pipe Calculations -Section 7
Inlet Invert Outlet Invert 1 O year storm 100 year storm
Pi pe# Size L ength Sl o pe Elev Elev *Actual Flow Design Flow V10 °lo Full
Travel Time, tT1o *Actual Flow Des ign Flow V100 %Full
(i n ) (ft) (%) (ft) (ft) (cfs) (cfs) (fps) (sec) (min) (cfs) (cfs) (fps)
1 27 112.2 1.50 307.61 305.93 26.09 9.7 64.1 12 0 .19 28.28 9 .8 ---
2 27 293.6 1.18 3 11 .28 307 .85 15.77 7 .9 50.3 37 0 .62 1 7 .24 8 .1 --
3 24 114 .9 1.20 31 2 .78 311 .43 13.31 21 .5 8 .3 76.6 14 0 .23 14 .20 22.93 8 .4 -
4 18 28.0 1.30 3 13 .64 313 .28 6.68 10.79 7 .2 79.4 4 0 .06 7 .13 11 .5 1 7 .2
-
5 27 50.3 0.40 3 1 1.53 311 .33 10.93 4 .8 55.9 10 0 .17 14 .72 5.1
6 30 209.7 0 .65 31 1.08 309.65 22.29 6 .8 63.2 3 1 0 .51 30.02 7 .1
*T hese values reflect the actual flow for the 18" & 24" pipes . The design flow for these pipe sizes reflects a 25% reduction in pipe area .
(Refer to attached cal c ulat ion for specific information .)
67 .8
53 .0
81 .6
85.5
68.2
80.0
Travel Time, t T1 00
(sec) (min)
11 0 .1 9
36 0 .60
14 0 .23
4 0 .06
10 0 .16
30 0.49
City of College Station requirement to Reduce Cross-Sectional Are_a o f 18" & 24" Pipes by 25%
Using Mannings Equation from page 48 of the College Station Drainage Po licy & Design Standards Manual :
Q = 1.49/n * A * R213 * S 112
Q =Flow Capacity (cfs)
18" Pipe:
Pipe size (inches)= 18
Wetted Perimeter WP • (ft) = 4 .71
Cross-Sectional Area A, (ft2 ) = .766
Reduced Area AR. (ft2 ) = 1 .325
Hydraulic Radius R = A/WP· (ft) = 0 .375
Reduced Hydr Radius RR = AR/WP · (ft) = 0 .281
Roughness Coefficient n = 0 .014
Friction Slope of Conduit S1, (ft/ft) = 0 .01
Example Calculation :
Slope Flow Capacity
s Q
0.005 6.91
0 .006 7 .57
0.007 8.18
24" P ipe:
Pipe size (inches)=
Redu ced Flow Capacity
O red uced
4 .28
4 .69
5 .06
erence
uceiO
% Diff
O,ed
0. 6 19
0. 619
0. 619
24
Wetted Perimeter WP • (ft) = 6 .28
Cross-Sectional Area A, (tt2) = 3 .14
Red uced Area ~. (ft2 ) = 2 .355
Hydraulic Radius R = A/WP· (ft) = 0 .5
Reduced Hydr Radius RR = A R/WP• (ft) = 0 .375
Roughness Coefficient n = O .014
Friction Slope of Conduit S1, (ft/ft) = 0 .01
Example Ca lcu lation :
Slope Fl ow Capac ity
s Q
0.005 14 .89 ----
0 .00 6 16.31
0.007 17.61
Conclusion :
Reduced Flow Capacity
Oreduced
9.22
10 .1
10.9
% Diff erence
O red uceiQ
0.
0.
0.
619 --619
619
Multiply actual Q in 18" & 24" pipes by 1 .615 to refle c t a 25 % r
cross-secti ona l area ca ll ed for o n page 47 , parag raph 5 of the
ed ucti o n in th e
Colleg e Sta ti on
Drainag e Policy & Design Standard s manual.
-
Jvision Castlegate Subd
Section 7 -Pipe Flow Diagram
Q 10 (cfs )
Inlet 700 \ 6 .68 In let 702 I 10 .93
J, J,
Pipe4 I 6 .68 Pipe 5 I 10 .93
J, J,
Inlet 701 I 6 .63 In 1et 703 I 11 .36
J, .J,
Pipe 3 I 13 .31 Pipe 6 I 22 .29
J, J,
Inlet 705 I 2.46 Existing Drainage
J,
Pipe 2 I 15.77
J,
Inlet 704 \ 10.32
J,
Pipe 1 I 26 .09
.J,
Exist. June Box 5 ~I Ex ist. Pipe 17 I 8 .91
.J,
I\ Exist. Pipe 16 / 35.00 II
-
I
I
Castlegate Subclivision
Section 7 -Pipe Flow Diagram
_____ 0_1 o_o_( cfs) I
Inlet 700 I 7 .13 Inlet 702 I 14 .72
J, J,
Pipe4 I 7 .13 Pipe 5 I 14.72
J, J,
Inlet 701 I 7.07 Inlet 703 I 15 .30
J, "' Pipe 3 I 14 .20 Pipe 6 I 30 .02
J, J,
Inlet 705 I 3.04 Existing Drainage
J,
Pipe 2 I 17 .24
J,
Inlet 704 I 11 .04
J,
Pipe 1 I 28 .28
J,
Exist. June Box 5 ~ I Exist. Pipe 17 I 11 .00 I
"' II Exist. Pi pe 16 I 39 .28 II
-
Pipe 1 -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 ....................... .
Hydraulic Radius ............... .
Percent Full ................... .
Full flow Flowrate ............. .
Full flow velocity ............. .
Circular
Depth of Flow
27.0000 in
26.0900 cfs
0.0150 ft/ft
0. 0140
17.2965 in
. 3.9761 ft2
2.6904 ft2
50 .1083 in
84.8230 in
9.6975 fps
7 .7316 i n
64 .0610 %
35 .2214 cfs
8 .8583 fps
Pipe 1 -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 ...................... .
Veloc i t y ....................... .
Hyd r aul ic Ra di us ............... .
Percent Full ................... .
Ful l flow Flowrate ............. .
Full flow ve locity ............. .
Cast l ega te Subdivision -Sec tion 7
College Statlon, Texas
Circu:).ar
Depth of Flow
27.0000 in
28 .2800 cfs
0.0150 ft/ft
0.0140
18 .3167 in
3 .9761 ft2
2 .8716 ft2
52.2620 in
84.8230 in
9 .8481 fps
7 .9 1 23 in
67.8396 %
35.2214 cfs
8.8583 fps
Pipe 2 -10 Year Storm
Manning Pipe Cal cu lator
Give n 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
27 .0000 in
15 .7700 cfs
0. Oll8 ft/ft
0 . 0140
13 . 576 5 in
3.9761 ft2
2.0024 ft2
42 .5645 in
84 .8230 in
7 .8756 fps
6 .7743 in
50 .2833 %
31 .23 93 cfs
7 .8568 fps
Pipe 2 -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 ............... .
Perimete r ...................... .
Velocity ....................... .
Hydraulic Radius ............... .
Percent Full ................... .
Full flow Flowrate ............. .
Full flo w veloc ity ............. .
Ca st legate Subdi v isi o n -Sectio n 7
College Station, Texa s
Circular
Depth of Flow
27.0000 in
17.2400 cfs
O .Oll8 ft/ft
0. 0140
14.3194 in
3.9761 ft2
2.1416 ft2
44 .0513 in
84 .8 23 0 in
8 .0501 fps
7.0006 in
53.0348 %
31.2393 cfs
7.8568 fps
Pipe 3 -10 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 ............. .
Circular
Depth of Flow
24 .0000 in
21 .5000 cfs
0 .0120 ft/ft
0. 0140
18.3896 in
3.1416 ft2
2.5830 ft2
51 .17 53 in
75.3982 in
8.3236 fps
7.2682 in
76.6231 %
23.0115 cfs
7 .324 8 fps
Pipe 3 -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 veloc ity ............. .
Castlegate Subdivision -Sect ion 7
College Stati o n, Texas
Circular
Depth of Flow
24.0000 in
22.9300 cfs
0 .0120 ft/ft
0 . 0140
19 .5941 in
3.1416 ft2
2.7460 ft2
54.1443 in
75.3982 in
8.3503 fps
7.3 032 in
81.6421 %
23.0115 cfs
7.3248 fps
Pipe 4 -10 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 ............. .
Circular
Depth of Flow
18 .0 000 in
10 .79 00 cfs
0 . 0130 ft/ft
0 .014 0
14 .2924 in
1 .767 1 ft2
1.5047 ft2
39 .5898 in
56 .5487 in
7 . 1708 fps
5 .4 731 in
79.4022 %
11 .1213 cfs
6 .2934 fps
Pipe 4 -100 Year Storm
Manning Pipe Calculator
Gi ven Input Data :
Shape .......................... .
Solving for .................... .
Diameter ....................... .
Flowrate ....................... .
Slope .......................... .
Manning's n .................... .
Computed Results:
Depth .......................... .
Area ........................... .
Wetted Area .................... .
Wetted Perimeter ............... .
Perimeter ...................... .
Ve locity ....................... .
Hydraulic Radius ............... .
Percent Full ................... .
Full flow Flowrate ............. .
Full flow velocity ............. .
Castlegate Subdivision -Section 7
College Stat i on, Texa s
Circular
Depth of Flow
18.0000 in
11.5100 cfs
0. 0130 ft/ft
0. 0140
15.3916 in
1.7671 ft2
1.6091 ft2
42.4900 in
56.5487 in
7.1533 fps
5.4531 in
85 .5091 %
11.1213 cfs
6.2934 fps
Pipe 5 -1 0 Year Storm
Manning Pipe Calculator
Give n 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
2 7 .0 0 00 in
1 0 .93 00 cfs
0.00 4 0 ft/ft
0 .0 140
15.0883 in
3.9761 ft2
2.2852 ft2
45 .5955 in
84.8 2 30 in
4.7830 fps
7.2170 i n
55.8826 %
18 .1882 cfs
4 .5744 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 ...................... .
Ve loc i t y ....................... .
Hy dr auli c Ra diu s ............... .
Percent Full ................... .
Full flow Flowrate ............. .
Full flow velocity ............. .
Cast l ega t e S ubdi visio n -Sec ti o n 7
College Statio n, Texas
Circular
Depth of Flow
27.0000 in
14.7200 cfs
0 .0040 ft/ft
0. 0140
18 .4 240 in
3 .9761 ft2
2 .8904 ft2
52 .4922 in
8 4 .8 2 30 in
· 5. 0 92 7 f ps
7.9291 i n
68.2372 %
18.1882 cfs
4.5744 fps
Pipe 6 -10 Year Storm
Manning P i pe Ca l c ul at o r
Give n Input Da t a :
Shape .......................... .
Solving fo r .................... .
Diame te r ....................... .
Flowr a te ....................... .
Slope .......................... .
Manning 's n .................... .
Com p uted Results :
Depth .......................... .
Area ................... · · · · · · · ·.·
Wetted Area .................... .
Wetted Perimete r ............... .
Perimeter ...................... .
Veloci ty ....................... .
Hy drau lic Radius ............... .
Percent Full ................... .
Full flow Flowrat e ............. .
Full flow velocity ............. .
Ci r cu lar
Depth o f Flow
30.0000 i n
22.290 0 c fs
0 .0 065 f t/ft
0.0 140
18.95 32 i n
4.9087 ft2
3 .2 683 ft2
55.12 4 8 in
94.24 78 i n
6 .8 20 0 f ps
8.53 77 in
63 .1 77 3 %
30 .707 0 cfs
6.2 55 6 fps
Pipe 6 -100 Yea r 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 ...................... .
Ve loc ity ....................... .
Hydraulic Radius ............... .
Percent Full ................... .
Full fl o w Fl owra t e ............. .
Full f low velocity ............. .
Castlegate S ubdi visio n -Section 7
College Station, Texas
Circular
Depth of Flow
30.0000 i n
30 .0200 cfs
0.0065 ft/ft
0. 0140
2 4 .00 4 0 in
4.9 0 87 ft2
4 .21 05 ft2
66 .4390 in
94.24 78 in
7.1 2 98 fp s
9 .1259 i n
8 0 .0 13 4 %
30.7070 cf s
6 .2556 fp s
EXHIBIT A
Post-Development Drainage Area Map
24
r
Drainage Report
for
Castlegate Subdivision -Section 7
College Station, Texas
April 2004
Developer:
Greens Prairie Investors, Ltd.
By Greens Prairie Associates, LLC
4490 Castlcgate Drive
College Station, Texas 77845
(979) 690-7250
Prepared By:
TEXCON General Contractors
1 707 Graham Road
College Station, Texas 77845
(979) 764-7743
CERTIFICATION
I certify that this report for the drainage design for the Castlegate Subdivision -Section 7, was
prepared by me in accordance with the provisions of the City of College Station Drainage
Policy and Design Standards for the owners hereof.
Ginge
TABLE OF CONTENTS
DRAINAGE REPORT
CASTLEGATE SUBDIVISION -SECTION 7
CERTIFICATION .................................................................................................................................................................. 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
Time of Concentration Equations & Calculations
APPENDIX B ........................................................................................................................................................................ 10
Storm Sewer Inlet Design Calculations
APPENDIX C ........................................................................................................................................................................ 13
Storm Sewer Pipe Design Calculations
EXHIBIT A ............................................................................................................................................................................ 24
Post-Development Drainage Area Map
LIST OF TABLES
TABLE 1 -Rainfall Intensity Calculations .......................................................................................... 4
TABLE 2 -Time of Concentration (tc) Equations .............................................................................. 4
TABLE 3 -Post-Development Runoff Information ............................................................................ 5
DRAINAGE REPORT
CASTLEGATE SUBDIVISION -SECTION 7
INTRODUCTION
The purpose of this report is to provide the hydrological effects of the construction of the
Castlegate Subdivision -Section 7, and to verify that the proposed storm drainage system
meets the requirements set forth by the City of College Station Drainage Policy and Desi gn
Standards .
GENERAL LOCATION AND DESCRIPTION
The project is located on a portion of a 111.46 acre tract located west of State Highway 6 along
the north side of Greens Prairie Road in College Station, Texas . This report addresses Section
7 of this subdivision, which is made up of 31.09 acres. Section 7 is located adjacent to
Castlegate Section 5 along Castlegate Drive. The site is predominantly wooded. The existing
ground elevations range from elevation 304 to elevation 336 . 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 . Most
of the proposed developed area of the site is located 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 February 9, 2000, panel number
48041C0205-D . A portion of this development is in Zone AE, a Special Flood Hazard Area
inundated by the 100-year flood. This area is shown on Exhibit A as the 100-year floodplain
limit. Also shown on this exhibit are the floodway limits as determined by the Castlegate
Floodplain Analysis Report which was previously submitted. The Flood Hazard Area along
Spring Creek Tributary A2B within this development has been designated as Greenway Area,
which will have no development and it will be left in its current condition. The Flood Hazard
Area along Spring Creek Tributary A2A encroaches on four proposed lots, as shown on Exhibit
A. A drainage easement has been created along the rear of these lots to prevent development in
the Flood Hazard Area. Also, a minimum finished floor elevation (FF) is required for these
lots, which is a minimum of 3 feet above the Base F lood Elevation (BFE).
DEVELOPMENT DRAINAGE PATTERNS
Prior to development, the storm water runoff for Section 7 flows in two different directions . A
portion of the runoff flows in a northeasterly direction until it enters a Tributary A2B of Spring
Creek. The remainder of th e runoff from this site flows in a northwesterly direction in to
Tributary A2A of Spring C reek. Ultimately , bo th tributaries flow into Sprin g Creek and th en
north to the propos ed reg ion a l dete nti on fac ilit y. R efe r to the v icinit y map in Ex hibit A fo r th e
loca ti on of thi s reg io na l de tention faci lit y .
DRA IN AGE D ES IGN CRITERIA
T he d es ig n par a me te rs fo r th e s to rm se we r anal ys is a rc as fo ll ows:
• The Rationa l Method is utili ze d to d e te rmin e peak s torm wa te r run o ff ra tes for th e s torm
sewe r de s ign a nd d ete nti o n fac ilit y a nal ys is.
·'
• Design Storm Frequency
Storm sewer system
• Runoff Coefficients
Pre-development
10 and _ 100-year storm events
Post-development (single family residential)
c = 0.30
c = 0 .50
• Rainfall Intensity equations and values for Brazos County can be found in Table 1.
• Time of Concentration, tc -Calculations are based on the method found in the TR-55
publication. Refer to Table 2 for the equations and Appendix A for calculations . The
runoff flow path used for calculating the post-development time of concentration for
Drainage Area 3 is shown in Exhibit A. The remainder of the drainage are as use a
minimum tc of 10 minutes to determine the rainfall intensity values.
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 drainage areas for the
post-development condition are shown on Exhibit A. Post-development runoff conditions for
the storm sewer design are summarized in Table 3.
TABLE 1 -Rainfall Intensity Calculations
Rainfall Intensity Values (inlhr)
Storm tc =
Event 10 min
Is 7.693
110 8 .635
hs 9.861
lso 11 .148
1100 11 .639
Brazos County:
5 'i.ear storm 10 'i.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)
le= U(V*60)
tc = Time of concentration (min)
L = Length (ft)
V = Velocity (ftlsec)
25 'i.ear storm 50 'f.ear storm 100 'i.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 Hiqhwa'f.S and Public Transportation H'f.draulic Manual, page 2-16)
TABLE 2 -Time of Concentration (t c) E quation s
The ti m e of con c e 11 t ratio11 was d e te r 111in ed us in g m e thods found in TR-55 , "Urban
Hy dro l ogy fo r S111a ll Wa t e rs he d s. " The equa ti o ns a re as f o llows:
Time of o nce ntr at ion:
Fo r Sh eet I-l ow :
Tc == Tqs hc t.·1 ll o") + T 1{to 11 n·111 ..-a1t·tf sln·t..·t tl o \\)
w here: T 1 =T ravel Time , minute s
0 .007 (11 L)0 s
(P2)
0
·' s0
A w he re : T 1 =tr ave l ti me . hour s
n =Manning 's roughness coefficient
L = flow length , feet
· P2 = 2-year, 24-hour rainfall = 4 .5"
s = land slope, ft/ft
For Sha ll ow C oncentrated Flow: T 1 =LI (6 0*V)
R efer to Appendix A for calculations.
where: T 1 =travel time , minutes
V =V e lo c ity , fp s (S ee Fig 3-l , App. E)
L = flow len gth , feet
TABLE 3 -Po st-Deve lopm e nt Ru noff In fo rm atio n
A c tc
5 year s t orm 10 yea r storm 25 year storm 50 year sto r m 100 year s to rm
Area# Is O s 110 0 1"0 l2s 0 2s lso O so 1100 0 100
(acres ) (m i n) (i n /hr) (cfs) (i n/hr ) (cfs ) (i n /hr) (cfs ) (i n /h r) (cfs) (i n /hr) (cfs )
1 0 .11 0.5 10 7.693 0.42 8 .635 0.47 9.861 0 .54 11 .148 0 .61 11 .639 0 .64
2 1.61 0 .5 10 7 .693 6 .19 8 .635 6 .95 9.861 7 .94 11 .148 8 .97 11 .639 9 .37
3 2.42 0 .5 14 .6 6.462 7.82 7.289 8 .82 8 .341 10.09 9.448 11.43 9 .8 58 11 .93
4 2.04 0.5 10 7.693 7 .85 8 .635 8.81 9 .861 10.06 11 .148 11.37 11 .639 11 .87
5 0 .49 0 .5 10 7 .693 1.88 8 .635 2 .12 9.861 2.42 11.148 2 .73 11 .639 2 .85
6 0 .21 0 .5 10 7 .693 0 .81 8.635 0 .91 9 .861 1.04 11 .148 1.17 11 .639 1.22
7 0.11 0.5 10 7.693 0 .42 8 .635 0.47 9.861 0 .54 11 .148 0 .61 11 .639 0 .64
8 0 .52 0 .5 10 7 .693 2.00 8.635 2 .24 9 .861 2 .56 11 .148 2 .90 11.639 3.03
9 2.47 0 .5 10 7 .693 9 .50 8.635 10.66 9.861 12 .18 11.148 13.77 11 .639 14 .37
10 0 .57 0 .5 10 7.693 2 .19 8 .635 2.46 9 .861 2 .8 1 11 .148 3.18 11 .639 3 .32
D ETENTIO N FACI LITY DES IGN
The detention facility hand ling the runof~ from this site is a regional facility designed by LJA
Engineering & Surveying, Inc. Also, a detention pond was constructed upstream of Castlegate
Drive to reduce th e peak flow resulting from th e Castlegate develo pment. The detention
facility is located adjacent to Spring Creek prior to Spring Creek entering the State Highway 6
right-of-way.
STO RM S EWE R DES IGN
The storm sewer piping for this project has been selected to be Reinforced Concrete Pipe
(RCP) meeting the requirements of ASTM C-76, Class III pipe meeting the requirements of
ASTM C-789. The curb inlets and junction boxes will be cast-in-place concrete .
A ppendi x B presents a summary of th e storm sewer inlet d es ign parameters and calculations .
T he inl ets were d es ig ned b ased on a I 0-year d es ign s torm . As per Co ll ege Stat ion g uid e lines,
the capacit ies of inl ets in s ump were red uced b y I 0% to allow for clo gg ing .
Inl e ts fo r th e res identia l s tr eets vver e loca ted to m a int a in a g utter flow depth of 5" or less. T hi s
des ig n d e pth w ill preve nt th e s pread of wa te r from reachin g th e crown of th e road for th e 10 -
ye ar s torm eve nt. Refe r to Appe ndi x B fo r a sum m a ry of th e g utter flow d e pt h s. The run o ff
int e rcepted by th e proposed s torm sewe r inl e ts was ca lcu la te d us in g th e fo ll owi n g eq uat ions .
T he d e pth of fl ow in th e g utt e r wa s d ete rmin ed b y us in g th e Stra ig ht C rown F low equa ti o n .
T he fl ow in te rc e pt e d b y Inl e ts 700, 70 I , 704 & 705 was calculated b y us in g th e C apacit y o f
Inl e ts On Gra ci e equa tion . These equati o ns and re s u ltin g d ata ar c summa ri zed in Appe ndi x 11.
The capacities for the inlets in sump (Inlets 702 & 703) were calculated using the Inlets in
Sumps, Weir Flow equation with a maximum allow_able depth of 7" (5" gutter flow plus 2"
gutter depression). These equations and the resulting data are also summarized in Appendix B.
The area between the right-of-way and the curb line of the streets will be graded as necessary to
provide a minimum of 6" of freeboard above the curb line . This will ensure that the runoff
from the l 00-year storm event will remain within the street right-of-way.
Appendix C 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 C as well. The pipes for the storm sewer system were
designed based on the l 0-year storm event, and they will also pass the l 00-year storm event.
Based on the depth of flow in the street determined for the l 00-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 maximum flow in the storm sewer pipe system
will occur in Pipe No . 6. The maximum velocity for the pipe system in this development will
be 9.8 feet per second and will occur in Pipe No. l. Appendix C contains a summary of the
pipe calculations as well as flow diagrams mapping the flows through the storm sewer system
for the 10 and 100-year events.
CONCLUSIONS
The construction of this project will increase the storm water runoff from this site . The
proposed storm sewer system should adequately control the runoff and release it into existing
drainages or the existing storm sewer system along Castlegate Drive . 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. The regional
detention facility should adequately control the peak post-development runoff so that it will not
have any impact on the properties downstream of the Crowley Tract.
APPENDIX A
Time of Concentration Equations & Calculations
7
Post-Development
Time of Concentration Calculations
Refer to Exhibit B for fl.ow paths used for calculations.
Drainage Area 3:
Sheet Flow: Flow length = 100' = L
Slope= 2.2%
n = 0.15, short grass prairi e
P2 = 4.5"
ti= 0.007 (0.15 * 100)°"8
(4.5)0 .S (0.022)0.4
ti= 0.133 hours = 8.0 minutes
Shallow Concentrated Flow: Flow length = 220' = L
Slope= 2.6%
Flow along Pavement:
For unpaved surface at 2.6%, Velocity (V) = 2 .6 fps (see Fig. 3-1)
ti = 220' I (60*2.6) = 1.4 minutes
Flow length, L @ Slope, S and Velocity, V
Using Figure 3-1 for paved surface to find V
L = 300'@ 1.25%, V = 2.25 fps
L = 265' @2.0%, V = 2.9 fps
L = 225'@ 1.5%, V = 2.5 fps
= 300/(60*2.25) + 265/(60*2 .9) = 225/(60*2.5) = 5.2 minutes
Tc= 8.0 + 1.4 + 5.2 = 14.6 minutes
....
<+--....
<+-
QJ
a.
0 ......
VI
QJ
VI
'-
::J
0
0
'-CIJ .µ ..,
:le
3-2
.50
.20 -
.10
.06
.04 -
.02 -
.01 -
.005
I
l
J
--~
I
' I
I
'
,,
~
~ " J
0 ~<l.J r·b,
'b' ..... <l.J ~~ 11
I
I
J
I
2
I
4
I
IJ
'
J
I
I
.JI
I
6
I
I/
'
' '
Ave r age ve l ocity , ft/sec
.
II .
' I
I
I
'
I I
10
II
II .
I
Fil(u"' ~-1.-,\veral(<: vclo.:itiu fo r c s tima t i noc l rJvd tim<: for shallow co n c<:nlraled Oow .
(210 -V l -TR -55. Seco nd Ed ., June 198G)
l
20
J •
APPENDIXB
Storm Sewer Inlet Design Calculations
10
Castlegate S ubd ivis io n
Section 7 , Castlegate Drive
In let L e ngth Ca lculat i ons
lnle1s In Sump
Inlet# Length & Type F1owftom A
Area# {acres)
4 2 .0 4 702 10' ------5 0 .49
703 10· 3 2.42 ----6 0.2 1
c
0.50
0.50
0.50 ---0.50
10year1torm
Q,. o....,". a,_ Or.w.tn y,,....._,
(cfs ) (els) ftom ...... (els) (els) (ft) (In)
8.81 8.81 9.69 0.350 4.20
2.12 2.12 2 .33 0.205 2.46
10.45 10.45 11 .49 0.373 4.47
. 0.9 1 0.9 1 1.00 0.149 1.79
Inlets On Grade 1 o year storm
Inlet#
700
70 1
705
70•
Length & Typ• Flow from y,. a,..,,oo1 o. .... ., o.,_. 0....-
Area# (ft) (in) (ft ) (el s) (els) (els)
10' 2 0.375 4.51 0.67 8.68 0.27 6.68 --10' 1 0.370 4 ,44 0.66 6.63 0 .06 6.63 -5· 10 0.280 3.36 0.58 2.68 -0 .42 2.46
15' 9 0.395 4 .74 0.69 10.32 0 .35 10.32
Transverse (Crown) slope (ft/ft)= 0.038 tnlel 704 (51' street width)= 0 .030
Straig ht Crown Flow (Solved to find actu al depth of fl ow. y):
a= o.56 • 1z1n1 • s '" · v"'"' y = {O / [0 .56 • (zln ) • 5 112])"'
n := Roughness Coeff ic1en1 =
z = Reciprocal of crown slope =
S = Street/Gutter Slope (fVft)
y = Depth of flow at inlet (ft)
Capacity of Inl ets on grade :
Oc = 0 .7 ' [1/(H 1 • H2)) • [H ,'". H2
512 ]
Oc =Flow capacity of inlet '(cfs)
H , =a • y
0 .0 18
26 Inlet 704 (51' street 'Nidth) = 33
H2 = a = gutter depression (2" Standard: 4" Recessed )
y = Depth of fl ow on approach gutt er (ft)
0.....-0...-
(els) ftom ...... (els)
0.2 7
0.06
0.06 701 0.00
0.35
100 year storm
L,,~ .. • L 11..au.1 o," o....,". o, ... OrotW+1n Y100
(ft) (ft) (els) (els)
9.00 10 11 .67
2 .85
9.35 10 14.08
1.22
•'*1g )lo..• r • o.583'
o..,. ... Ott.rot .. y,.,
(els) (els) (ft) (In)
6.68 6.95 0.420 5 .04
6.63 6.69 0.414 4.97
2.46 2.46 0.373 4.47
10.32 10.66 0.«2 5.30
In lets In s u mps, Weir Flow ;
L • Q I (3 • y:112 ) «> y • (Q I 3L),,,
L = Length of inlet opening (ft)
Q = Flow at inlet (els)
y = total depth of flow on Inlet (ft)
max y for inlet in sump = 7" = 0.583'
fromk'IMl l (cfs) (el s) (ft)
11.87 13.06 0.66 3
2.85 3.14
14 .08 15.49 0.680
1.22 1.34
100 year storm
o... .... o.. ... ., o.,_. 0....-
(ft) (els) (els) (els)
0.7 1 7.13 2.24 7.13
0.7 1 7.07 1.95 7.07
0.61 3.04 0.28 3.04
0.74 11 .04 3.34 11 .04
(In)
7.96
8.16
Cc.."'J'o.,.r o.,... ... o..,. ... 0100-T .... s L~ ... 1
(els) from ~let. (els) (els) (els) (ft/ft) (ft)
2.24 7.13 9.37 0.0134 10
1.95 7.07 9.02 0.0 134 10
1.95 701 2.23 3.04 5.27 0.0080 5
3.34 11 .04 14 .37 0.0 150 15
.c.
n. a; :0 g ~ ·3
_J ii) '2-
~
~ 0 ~ c lO .c. ~ 1 =o c + -~
w~
Castlegate Subdivision -Section 7
Depth of Flow i n Street Gutter
10 -year stor m 100 -year sto r m
Gutter A c Slope 0 10 Y10 -actual 0 100 Y100
Loc ati o n (a c res ) (ft/ft) (cfs) (ft) (in) (cfs) (ft)
81 1.55 0 .50 0 .0134 6.69 0.370 4.44 9 .02 0 .414 ·-------------------------·-· -·
82 1.61 0.50 0 .0 134 6.95 0 .375 4 .51 9 .37 0 .420
-------- ------------------------·
C1 1.65 0 .50 0 .0102 7 .12 0 .399 4 .79 9 .60 0 .446
-------------------------· ·-------·-
C2 0 .27 0 .50 0.0102 1.17 0 .202 2.43 1.57 0 .226 ----------------------___ ,_ ---
01 0 .21 0 .50 -----------
02 2.42 0 .50
-·-- - ------
03 0 .39 0.5
04 2 .04 0 .50
E1 0.57 0 .50
A1 2.47 0 .5
A2 0 .52 0 .50
Transverse (Crown) slope (ft/ft)
for loop street= 0 .0380
e ntrance = 0 .0300
0 .0080 0 .9 1
0 .0150 8.82
0 .0080 1.68
0 .0150 8 .81
0 .0080 2.46
0 .0 150 10 .66
0 .0150 2 .25
0 .193 2.31 1.2 2 0 .215 ------
0 .402 4 .82 11 .93 0.450
---·---------
0 .243 2.92 2.27 0 .272 ---
0.402 4 .82 11 .87 0.449 -----
0 .480 3 .36 3 .32 0 .313
0 .395 4 .74 14 .37 0.442
0.220 2 .64 3.03 0 .246 ----
Straight Cr own Flow (Solved to find actual depth of flow in gutter, y):
Q = 0 .56 * (z/n) * S112 * y813 ¢ y ={QI [0.56 * (z/n) * S112]}318
n =Ro ugh ness Co effic ient = 0 .018
S = StreeUGu tte r Slope (ft/ft )
y = Depth of fl ow at inlet (ft )
z = Reciproca l of crown sl o pe:
for loop street = 26
e ntrance = 33
----
--
(in )
4 .97
-·
5 .04 ·-
5 .35
2 .71
2 .59
5.40
3 .26
-
5 .39 ---
3 .76
5 .30
2.96 --
APPENDIXC
Storm Sewer Pipe Design Calculations
I ~
Castlegate Subdivision
Pipe Calculations -Section 7
Inlet Invert Outlet Invert 10 year storm 100 year storm
Pipe# Size Length Slope Elev Elev *Actual Flow Design Flow V10 %Full
Travel Time, tT1o *Actual Flow Design Flow V100 %Full
(in) (ft) (%) (ft) (ft) (cfs) (cfs) (fps) (sec) (min) (cfs) (cfs) (fps)
1 27 112.2 1.50 307 .61 305.93 26.09 9 .7 64 .1 12 0 .19 28 .28 9 .8
-----
2 27 293.6 1.18 311 .28 307.85 15.77 7 .9 50.3 37 0 .62 17 .24 8 .1
---
3 24 114.9 1.20 312 .78 311.43 13.31 21 .5 8 .3 76.6 14 0 .23 14 .20 22 .93 8 .4 --
4 18 28.0 1.30 313.64 313 .28 6 .68 10 .79 7 .2 79.4 4 0 .06 7 .13 11.51 7 .2 -
5 27 50.3 0.40 311 .53 311.33 10 .93 4 .8 55.9 10 0 .17 14.72 5 .1 -
6 30 209.7 0.65 311 .08 309.65 22 .29 6 .8 63 .2 31 0 .51 30.02 7.1
*Th ese values reflect t he actual flow for the 18" & 24" pipes. The design flow for these pipe sizes reflects a 25% reduction in pipe area .
(Refer to attached ca lculat ion for specific information.)
67 .8
53 .0
81.6
85.5
68.2
80 .0
Travel Time, tnoo
(sec) (min)
11 0.19
36 0 .60
14 0 .23
4 0 .06
10 0 .16
30 0.49
City of College Station requirement to Reduce Cross-Sectional Are_a of 18" & 24" Pipes by 25%
Using Mannings 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)=
Wetted Perimeter WP , (ft)=
Cross-Sectional Area A , (ft2 ) =
Reduced Area AR, (ft2 ) =
Hydraulic Radius R = A/WP • (ft) =
Reduced Hydr Radius RR = AR/W P· (ft) =
Roughness Coefficient n =
Friction Slope of Conduit S1, (ft/ft) =
Example Calculation :
Slope Flow Capacity Reduced Flow Capacity
s Q
0.005 6 .91
0.006 7 .57
0.007 8 .18
24" Pipe:
Pipe size (inches)=
Wetted Perimeter WP, (ft)=
Cross-Sectional Area A , (W) =
Reduced Area ~. (W) =
Oreduced
4.28
4 .69
5 .06
Hydraulic Radius R = A/WP · (ft) =
Reduced Hydr Radius RR = ~/WP • (ft) =
Roughness Coefficient n =
Friction Slope of Conduit Sr. (ft/ft)=
Example Calculation :
Slope Flow Capacity Reduced Fl ow Capacit y
s Q Or educe d
0 .005 14 .89 9.22 ---·------··--------
0.006 16.3 1 10.1 ----------------
0 .007 17 .61 10 .9
Conclusion :
18
4.71
1.766
1.325
0 .375
0 .281
0 .014
0 .01
% Difference
Oredu ceiO
0.619
0.619
0.619
24
6.28
3 .14
2 .355
0 .5
0 .375
0 .014
0 .01
% Differen ce
OreduceiO
0.619 ---
0.619 - - -
0.619
Multipl y actua l Q in 18" & 24" pip es by 1.615 to re fl ec t a 25 % re du c ti on in th e
cross-sec tional a rea ca ll ed for on page 47, pa r ag ra ph 5 o f th e Co ll ege Sta tion
Drain age Po licy & D es ig n Stand a rd s manual.
Castlegate Subd,ivision
Section 7 -Pipe Flow Diagram
010 (cfs)
Inlet 700 I 6 .68. Inlet 702 I 10 .93
J, J,
Pipe 4 I 6 .68 Pipe 5 I 10 .93
J, J,
Inlet 701 I 6 .63 Inlet 703 I 11.36
-It -It
Pipe 3 I 13 .31 Pipe 6 I 22.29
J, J,
Inlet 705 I 2.46 Existing Drainage
J,
Pipe2 I 15.77
J,
Inlet 704 I 10.32
J,
Pipe 1 I 26.09
-It
Exist. June Box 5 ~ I Exist. Pipe 17 I 8.91
"' II Ex ist. Pipe 16 I 35 .00 II
Castlegate Subdivision
Section 7 -Pipe Flow Diagram
Q 100 (cfs}
Inlet 700 I 7 .13 Inlet 702 I 14.72
J, J,
Pipe 4 I 7 .13 Pipe 5 I 14.72
J, J,
Inlet 701 I 7 .07 Inlet 703 I 15 .30
J, ,J.,
Pipe 3 I 14 .20 Pipe 6 I 30 .02
J, J,
Inlet 705 I 3 .04 Existing Drainage
J,
Pipe 2 I 17 .24
J,
Inlet 704 I 11 .04
J,
Pipe 1 I 28.28
J,
Exist. June Box 5 ~ I Exist. Pipe 17 I 11 .00
,J.,
II Exist. Pipe 16 I 39 .28 II
Pipe 1 -10 Yea r S torm
Mann ing Pipe Ca lcu lator
Given Input Data:
Shape .......................... .
Solving fo r .................... .
Diame t er ....................... .
Flowra te ....................... .
Slop e .......................... .
Manning's n .................... .
Computed Results :
Depth .......................... .
Area .......................... , .
Wetted Area .................... .
Wetted Perimeter ............... .
Pe r ime ter ...................... .
Velocity ....................... .
Hydrau li c Radiu s ............... .
Percent Fu l l ................... .
Full fl o w Flowr at e ............. .
Full flow velocity ............. .
Ci rcu l ar
Depth o f Flow
2 7.0 000 in
26.09 00 cfs
0.0 1 5 0 f t/ft
0.014 0
17.2 9 6 5 in
3.9 7 61 ft2
2 .6904 ft2
50.1083 in
84.8 2 30 in
9.69 7 5 fps
7.7 3 16 in
64.0 61 0 %
35.22 14 cfs
8.8583 fps
Pipe 1 -100 Year Storm
Mann i ng Pipe Calculator
Giv en Input Data:
Shape .......................... .
Solving for .................... .
Diameter ....................... .
Flowrate ....................... .
Slope .......................... .
Manning' s n .................... .
Computed Results:
Depth .......................... .
Area ........................... .
Wetted Area .................... .
Wetted Perimeter ............... .
Pe r imete r ...................... .
Ve l o c ity ....................... .
Hydraulic Radius ............... .
Percent Full ................... .
Full flow Flowra t e ............. .
Full flow velocity ............. .
Ca s tl e g ate S u bdiv isi on -Section 7
College Statl o n, T exa s
Circu)..ar
Depth of Flow
27 .0000 in
28 .2800 cfs
0.0150 ft/ft
0.0140
18.3 1 6 7 in
3.97 6 1 ft2
2.8 7 16 ft2
52.2 6 2 0 i n
84 .8 2 30 in
9 .8 481 f p s
7.9123 in
67.8396 %
35 .2214 c fs
8.8583 fps
Pipe 2 -10 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 ............. .
Circular
Depth of Flow
27.0000 in
15.7700 cfs
0 .0118 ft/ft
0. 0140
13 .5765 in
3 .976 1 ft2
2.0024 ft2
42.5645 in
84.8230 in
7.8756 fps
6.7743 in
50.2833 %
31.2393 cfs
7.8568 fps
Pipe 2 -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 ............. .
Cas tl egate S ubdi v ision -Sect i o n 7
College Stat j o n, T e xas
Circular
Depth of Flow
27.0000 in
17.2400 cfs
0.0118 ft/ft
0. 0140
14 .3194 in
3.9761 ft2
2.1416 ft2
44. 0513 in
84 .8230 in
8.0501 fps
7.0 006 in
53.0 348 %
31.2393 cfs
7.8568 fps
Pipe 3 -10 Year Storm
Manning Pipe Ca l c u lator
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
24.0000 in
2 1 .50 00 cfs
0.0 12 0 ft/ft
0. 0140
18. 3896 in
3.1416 ft2
2 .5830 ft2
51.1753 in
75.3982 in
8 .3 2 36 fps
7 .2 68 2 in
76.6 231 %
23.0115 cfs
7.3248 fps
Pipe 3 -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 ....................... .
Hy draul ic Ra diu s ............... .
Perc ent Full ................... .
Full f low Flowrate ............. .
Fu ll flow velocit y ............. .
Castlega t e S u b d ivis i o n -Sec t i o n 7
College Station, Texa s
Circular
Depth of Flow
24 .0000 in
22.9300 cfs
0.0120 ft/ft
0. 0140
19 .5941 in
3 .1416 ft2
2 .7460 ft2
54 .1443 in
75 .3982 in
8.3 503 fps
7.3032 i n
81.6421 %
23.0115 cfs
7.3248 fps
Pipe 4 -10 Year Storm
Manning Pipe Calculator
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
18 .0000 in
10.7900 cfs
0 .0130 ft/ft
0. 0140
14.2924 in
1. 7671 ft2
1.5047 ft2
39.5898 in
56 .5487 in
7.1708 fps
5.4731 in
79.4022 %
11 .12 13 cfs
6.2934 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 ubdiv i s i on -Sect i o n 7
College Stat j on, Texas
Circular
Depth of Flow
18.000 0 in
11.5100 cfs
0. 0130 ft/ft
0. 0140
15.3916 in
1 .7671 ft2
1 .6091 ft2
42.4900 in
56.5487 in
7 .1533 fps
5.4531 in
85. 5091 %
11.1 213 cfs
6.2934 fps
Pipe 5 -10 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 ............. .
Circular
Depth of Flow
27.0000 in
10.9300 cfs
0.0040 ft/ft
0 .0140
15 .0883 in
3 .9761 ft2
2.2852 ft2
45.5955 in
84.8230 in
4.7830 fps
7.2170 in
55.8826 %
18.1882 cfs
4 .5744 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 ............. .
Castlega t e S ubd ivisio n -Section 7
College Statio n, Texas
Circular
Depth of Flow
27 .0000 in
14 .7200 cfs
0.0040 ft/ft
0.0140
18.4240 in
3.9761 ft2
2.8904 ft2
52.4922 in
84.8230 in
· 5.0927 fps
7. 9291 in
68.2372 %
18 .1882 cfs
4.5744 fps
P i pe 6 -10 Year Storm
Manning P i pe Ca lculator
Giv en Input Da ta :
Shape .......................... .
Solv i n g f or .................... .
Diamet e r ....................... .
Flowr at e ....................... .
Slope .......................... .
Manni ng's n .................... .
Co mputed Results :
Depth .......................... .
Area ................... · · · · · · · ···
Wetted Area .................... .
Wetted Perimeter ............... .
Perimeter ...................... .
Velocity ....................... .
Hy draulic Radius ............... .
Percent Full ................... .
Full f low Flowr ate ............. .
Full flow velocity ............. .
Circul a r
De p t h of Flow
30 .00 0 0 in
22 .29 00 cfs
0.006 5 f t/ft
0 . 014 0
18 .9532 in
4 .9087 ft 2
3 .2683 ft 2
55 .1248 in
94 .2 478 in
6.8 2 00 fps
8 .5 3 77 in
63.17 7 3 %
30.7 070 cfs
6.2556 fps
Pipe 6 -100 Yea r Storm
Manning P i pe Calculator
Given Input Data :
Shape .......................... .
Solving for .................... .
Diameter ....................... .
F lowrate ....................... .
Slope .......................... .
Manning ' s n .................... .
Computed Results :
Depth .......................... .
Area ........................... .
Wetted Area .................... .
Wetted Perimete r ............... .
Perimeter ...................... .
Vel o ci t y ....................... .
Hy d raulic Radius ............... .
·Percent Full ................... .
Full flow Flowrate ............. .
Full flow velocity ............. .
Castlegate Subdivision -Sectio n 7
College Statio n, Texas
Circular
Depth of Flow
30 .0000 in
30.0200 cfs
0 .0065 ft/ft
0 . 0140
24 .0040 in
4 .9087 ft2
4 .2105 ft2
66 .4390 in
94.24 78 i n
·7.129 8 f ps
9 .1259 in
80.0134 %
30.7070 cfs
6.2556 fps
EXHIBIT A
Post-Development Drainage Area Map
24
TEXCON GENERAL CONTRACTORS 07 -May-04
ENGINEER'S COST ESTIMATE
CASTLEGATE SUBDIVISION
COLLEGE STATION, TEXAS ·
SECTION 7 -24 LOTS
Item Estimated Unit Estimated
No. Description Quantity Price Cost
Sitework
1 Mobilization/Layout 1.0 LS $10,000 .00 $10,000
2 Site Preparation 3 .1 AC $3,500 .00 $10 ,850
3 Sediment & Erosion Control 1.0 LS $5 ,000.00 $5 ,000
4 Topsoil Stripping & Replacement 1,000 CY $4 .50 $4,500
5 Excavation 3 ,200 CY $3 .50 $11,200
6 Lime Stabilized Subgrade 8,660 SY $3 .25 $28 ,145
7 Concrete Curb & Gutter 5,010 LF $8.00 $40,080
8 Remove Existing Concrete Curb & Gutter 112 LF $6 .00 $672
9 Base Material -6" depth 6,665 SY $6.00 $39,990
10 Asphalt Paving -1 1 /2" depth 6 ,665 SY $5 .00 $33,325
11 Concrete Paving with Brick Pavers 1,425 SF $9 .00 $12,825
12 Concrete Apron 1,360 SF $5 .50 $7,480
13 Landscape Sleeves 60 LF $8 .00 $480
S ubtotal $204,547
Storm Drainage
14 Drainage Pipe -18" RCP -structural 28 LF $36 .00 $1 ,008
15 Drainage Pipe -24" RCP -non-structural 113 LF $36.00 $4,068
16 Drainage Pipe -27" RCP -non-stru ctural 270 LF $40.00 $10 ,800
17 Drainage Pipe -27" RCP -structural 187 LF $48.00 $8,976
18 Drainage Pipe -30" RCP -non-structural 210 LF $46.00 $9 ,660
19 Headwall/wingwalls -30" RCP EA $2,500 .00 $2,500
20 Inlets 5' wide 1 EA $2,600.00 $2 ,600
21 Inlets 1 O' wide 4 EA $3,20 0.00 $12,800
22 Inlets 15' wide 1 EA $3,60 0.00 $3,600
23 Remove 24" RCP Stub 6 LF $15.00 $90
24 Tie into Existing Junction Box EA $450 .00 $450
Subtotal $56,552
W ater Lines
25 8" Water PVC CL200 (C900) non-struct 2 ,152 LF $24.00 $51,648
26 8" Water PVC CL200 (C900) structural 34 LF $30.00 $1,020
27 Gate Valves -8" 4 EA $600 .00 $2,400
28 M .J . Tees -8" 1 EA $400 .00 $400
29 M .J . Te e s -8" x 6" 3 EA $300.00 $900
30 M .J . Ta p Te es -8 " x 3 " 1 EA $3 00 .00 $300
3 1 M.J . Be nd -8" 11 .25 d eg . 6 EA $3 0 0.00 $1,800
32 M.J. Be nd -8 " 2 2.5 d eg. 4 EA $4 50.00 $1,800
33 M .J . Be nd -8 " 4 5 d eg . 4 EA $5 0 0.00 $2,000
34 1" SS Wa te r Se rv ice 5 EA $6 00 .00 $3,000
35 1" LS Wate r Serv ice 4 EA $70 0.00 $2,800
36 1 1/2" SS Wa te r Service 2 EA $650 .00 $1,300
37 1 1/2" LS Wa ter Se rv ice 6 EA $750.00 $4,500
38 2" Blow off Assemb ly 1 EA $450.00 $450
39 Fi re Hyd ra nt Asse m b ly w/ ex te n s io n 3 EA $2,500 .00 $7,500
40 Conne c t to ex is ti ng line EA $350.00 $350
Subtotal $82, 168
Sanitary Sewer Lines
41 6" SOR 26 Pipe -struct; avg depth <8 ' 341 LF $26 .00 $8 ,866
42 6" SOR 26 Pipe -non-str; avg depth <8' 461 LF $18 .00 $8 ,298
43 6" SOR 26 Pipe -struct; avg depth 8'-10' 348-LF $28.00 $9,744
44 6" SOR 26 Pipe -non-str ; avg depth 8'-10' 128 LF $20.00 $2 ,560
45 6" SOR 26 Pipe -non-str ; avg depth 10'-12 ' 330 LF $24 .00 $1 ,920
46 6" SOR 26 Pipe -non -str ; avg depth 12'-14' 150 LF $28 .00 $4,200
47 8" SOR 26 Pipe -non-str; avg depth 8'-10' 165 LF $22.00 $3 ,630
48 6" ASTM-02241-struct; avg depth 8'-10' 20 LF $28 .00 $560
49 Sewer Services 14 EA $700.00 $9 ,800
50 Manholes -average depth <8' 3 EA $2 ,200 .00 $6,600
51 Manholes -average depth 8'-1 O' 3 EA $2,400 .00 $7 ,200
52 Manholes -average depth 10'-12' EA $2,600 .00 $2 ,600
53 Manholes -average depth 12'-14' EA $2,800 .00 $2 ,800
54 Connect to existing manhole EA $750 .00 $750
55 Manhole Drop Connection EA $750 .00 $750
Subtotal $76,278
Total Sitework $204,547
Total Storm Drainage $56,552
Total Water $82,168
Total Sanitary Sewer 76 278
TOTAL CONSTRUCTION $419,545
Page 2 of 2
DEVELOPMENT PERMIT
PERMIT NO . 04-18A ~-,
Project: CASTELGATE SUBDIVISION SECTION 7
COLLlGl STATION FOR AREAS INSIDE THE SPECIAL FLOOD HAZARD AREA
RE: CHAPTER 13 OF THE COLLEGE STATION CITY CODE
SITE LEGAL DESCRIPTION:
31 . 094 Acres
Robertson Stevenson Survey
A-54
DATE OF ISSUE: 04/23/04
OWNER:
Greens Prairie Investors, Ltd .
4490 Castlegate Drive
College Station , Texas 77845
TYPE OF DEVELOPMENT:
SPECIAL CONDITIONS:
Clearing Permit
SITE ADDRESS:
2270 Green's Prairie Road
DRAINAGE BASIN:
Spring Creek
VALID FOR 6 MONTHS
CONTRACTOR:
All construction must be in compliance with the approved construction plans
All trees required to be protected as part of the landscape plan must be completely barricaded in accordance with Section
7.5.E., Landscape/Streetscape Plan Requirements of the City's Unified Development Ordinance, prior to any operations of
this permit. The cleaning of equipment or materials within the drip line of any tree or group of trees that are protected and
required to remain is strictly prohibited . The disposal of any waste material such as, but not limited to, paint , oil , solvents ,
asphalt, concrete , mortar, or other harmful liquids or materials within the drip line of any tree required to remain is also
prohibited .
TCEQ PHASE II RULES IN EFFECT
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.
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 inside 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 .
(Jgive -D-a-te_()_'{_-_Z_3_-_D_t~---------
~ >.dh~ 4~~ ~'lfa..i<..;;...;;;.$P~kf+-------
Owner/Agent/Contractor Date
TCEQ Office Use Only Notice of Intent (NOi) for Storm Water Discharges
Associated with Construction Activity under the
TPDES Construction General Permit (TXR1 soa.op)
TPDES Permit Number : TXR 15·.:_·.:_·.:_· .:_·._N O
GIN Number: • • • • • • • • • • • • • • • •
For help completing this application. read the TXR 150000 NOi Instruct ions
(TCE0 -20022 -l nslructions).
-------
A . Construction Site Operator. 0New ~No Change
Name: OJ( v 4 d .
Customer Reference Number: CN GIJZ#SJ{e$lJ 1
Mailing Address : 449 0 CA~~a:t.., Tu-!y"e-City: 'OY\ State :l!_Zip Code : "]:JfA-S-
Country Mailing Information (if outs7d~A) Territory: ___ -______ Postal Code :
Phone Number: (414) /e'1o -12-SD Extension : ______ Fax Number: (4 Jq)Cl1D -/ 04-/ ---
E-mail Address : __________________ -,-________________________ _
Type of Operator: 0 Individual 0 Sole Proprietorship -D .B.A. g Partnership 0 Corporation 0 Federal Government
D State Government 0 County Government 0 City Government 0 Other: ---------------------
1 n dependent Operator? jiaYes D No Number of Employees :~ 0-20 0 21-100 0 101-250 0 251-500 0 501 or higher
Federal Tax ID : 14-G-Cl"743Jo State Franchise Tax ID Number:· ·tJ/A DUNS Number: WA
B. Billing Address •
Name: \\J~La.u. JhllltpS -6GRY1_~J?.1,Jc\f Tuved"tY-~1 LhL ,
Ma iling Address : 4410 Cac.,ii .. ttyct<.;J~tl\(('..... City:CotlP~P ~a.fiOYI State :~ZipCode : llfffS
Country Mailing Information (if outside USA) Territory: Count~tode: -Postal Code :_-__
C. Project I Site Information ~New 0No Change Regulated Entity Reference Number: RN _________ _
Name: Cast~-Q.. ~ht.Dlon-~-h' DnS S-(,., t J
Mailing Address: l!43<i CA..£it"LLJ;a:::&:Dfj ~ . -ci&: CO/! etjr Sta.flM State:JX. Zip Code : 1--rrltS-
Physical Address : .itlonci ~:U:lfi ~ VfJ _ , City:Wtl~~M ~ounty: ~g :J;0S Zip Code : :1J'b4-S""
Location Access Descriptibn: S?vJ.b rl' Y1dw1~])o"e on Ga.s~,ve..,
Latitude: 32 •?fl..· tt" N Longitude :~ 0 J/Q_ · 3k_" W Degrees (0
). Minutes('). and Seconds(")
Latitude : Longitude : -Decimal Form
Also . describe the construction activity at this site (do not repeat the SIC code):
~..-=-I
Has a storm water pollution prevention p!an been prepared as specified in the general permit (TXR 150000)? ®Yes 0 No
Estimated area of land disturbed (to the nearest acre): /!2"" Is the project I site located on Indian Country Lands? 0 Yes JKl' No
Does this project I site discharge storm water into a municipal separate storm sewer system (MS4 )? D Yes 181 No
If yes, provide the name of the MS4 operator :-----------------------------~---
Provide the name or segment number of the water body that receives storm water from this project I site:
D . Contact -If the TCEQ needs additional information regarding this application, who should be contacted?
Name: \kh.\A.~a.:&.i.Hll2.~ ntle: W\tt.-Mtv,,\"'"
Phone Number: l'i11){fic);=J£§) Extension: Fax Nu~ber: (1-iq){&O-to41
E-mail Address :
E. Payment Information -Check I Money Order Number: Name on Check I Money Order:
F. Certification
I certify under penalty or law that this document was prepared under my direction or supervision in accordance with a system designed to assure that qualified
personnel property gather and evaluate the information submitted . Based on my inquiry of the person or persons who manage th e system . or those person s
directly responsible for gathering the information. the information submitted is. to the best of my knowledge and belief. true, accurate. and complete . I am
aware there are significant penalties for submitting false information. induding the possibility or fine and imprisonment for knowing violations .
Construction Site Operator:
Prefix : roe. First: Walla CL Middle : _______________ _
Last: fu.\ \Up? Suffix: ::r.n:..... Tit1e:_ ..... W\~a.J/\~4~t""«~-----------
Signature : (1!~~ i $evi d&'vi:J fJVt 4A2:/o4-) Date:----------
1r you have questions on how lo fill out this form or about the storm water program . pl ease contact us at (512) 23g-4671 .
Individuals are entitled to request and review their personal information that the agency gathers on its forms . They may also have any errors in their inform atio n
corrected . To review such information. contact us at (512) 23g .32a2 .
rc:r:o .;onn tn'.i1o:i1
The completed NOi must be mailed lo the following address . Use the attached document to submit the $100
application fee . Please note that th e NOi and application fee are submitted separate ly to different addre sses .
Texas Commission on Environmental Quality
Storm W ater & General Permits Team; MC -228
P .0 . Box 13087
Au s tin . Texa s 78711 -3087
P ;i <Jc 1 ol
' ~
~'1'
C.OlllGl STATION
DEVELOPMENT PERMIT
MINIMUM SUBMITTAL REQUIREMENTS r!1 $200.00 development permit fee . J6f.
~ Drainage and erosion control plan , with supporting Drainag Ef'Report two (2) cop ies each
~ Notice of Intent (N .0.1.) if disturbed area is greater than 5 acres
t 1f> ~ ~+\--(t\ wi.fh ~IAl.-fl'trn Jv-&LWl~!t f.
Date of *Required' Preapplication Conference:_>N__..+/4~~~---------------
*(Required for areas of special flood hazard ) /
LEGAL DESCRIPTION 3 I. a 'ff: aaetg in :!he, ~btd: 1&ensuri ?Wve;, I A -'i!f:_@<.l~qt<JJ., I
APPLICANT'S INFORMATION (Primary Contact for the Project): s:.ed-JfJYI 7)
Name \\J«.-llw "fttill l'ps E-Mail _-________ _
Street Address 't¥f o Otst~]?cl v-e....
City Co1Le'1e 9"-a...firo State ----oTI_,_______ Z ip Code 1J84S-
Phone Nu m ber (1:¥J) i;q0 -1250 Fax Number _.,{;J_~~/q_._).._b~'l ....... O~-___.L~0_,__4-~/ __ _
PROPERTY OWNER'S INFORMATION:
Name Gr ..eeJ12Jta,iri'e .:Jrt Vfh.fv61 lfJ . E-Mail _________ _
Street Address +¥Io Ctt7~:t., Jdr-1 v-L
City [o lletje 9="'l-fl9Yl state __ TI~---Zip Code :JJW')
Phone Number (tflq) (tfO-Tl.Sf) Fax Number _(.__1_"-'7~q_,_)~~~'lO~-~' D~4=_1 __ _
ARCHITECT OR ENGINEER'S INFORMATION :
Name :(.LkoVl-Joe S:hu.\ft;1 P ~£. E-Mail joe~l.!..\t-c@ ~o~-vt-e_f-
Street Address \:J Dl frtLha..ro ~
City Gol\9e.. S;tctl; OY\ State _Ti~----Z ip Code 11.'B'ts=
Phone Number {;{1q~ 1 b't-114=3 Fax Number (11tf J1lo4-77SC'j
Application is hereby made for the following development specific s ite/waterway alterations :
t'hi~ p!twl.
ACKNOWLEDGMt::NTS : ~l l'!Nl \I s I, ~~ign en cl ~ee ~/owner . hereby ac knowledg e o r affirm t hat:
,
Th e informat ion and con c lus ions conta in e d in th e ab o ve plans and s u pp ortin g d oc uments comply wit h th e c urre nt
requi re me nts of t he C ity of Coll eg e Stat ion , Te x as C ity Co d e , Ch apter 13 a nd its assoc iated Dra inage Pol icy an d
Desig n ·St a nd a rds .
~f' &-M u.ME ~'IP'i
Prope rty Owner(s
6/13/03 1 of 2
As a cond ition of approval of this permit applicatio n , I agree to construct t he improvements proposed in this
application according to these documents and the requirements of Chapter 13 of the College Station City Code
~gfj¥ & lVAu.N.£ ~
Contractor
CERTIFICATIONS:
A. I, __ , certify that any nonresidential structure on or propo sed to be on this site as part of this appl ication
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 , includ ing 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 Adm inistration Flood Ha zard Study and maps , as amended .
Engineer Date
Engineer Dat e
Co nditions or commen ts as part of approval : ________________________ _
In acc ord ance wi th Ch ap t er 13 of the Cod e of Ordi na nces of th e City of Col le ge Sta tion , measu res shall be take n
to ins ur e t hat de bris from co nstruction , erosio n, a nd sedi mentat ion shall not be deposited in cit y st reets , or
existing drainage faci lit ies . A ll developme nt shall be in acc ordan ce wit h th e pla ns and specificat io ns s ubm itted to
a nd a ppro ve d by th e C ity Engine er fo r th e above named proj ect. A ll of th e applica bl e codes and ord in ances of
t he Ci ty of Co lleg e Sta tion shall ap ply .
6/13/03 2 of 2