HomeMy WebLinkAboutSewer Analysis*CIVIL DEVELOPMENT, Ltd.*
CIVIL ENGINEERING & DESIGN-BUILD SERVICES
P.O. Box 11929 · College Station, Texas 77842 · Phone: 979-764-7743 · Fax: 979-764-7759
September 29, 2008
Carol Cotter, P.E.
City of College Station
P.O. Box 9960
College Station, TX 77842
RE: Sewer Analysis and Report
Castlerock Subdivision, Phase 2B
College Station, Texas
Dear Carol:
No new report for the sewer system in Castlerock Subdivision, Phase 2B will be
submitted at this time. The system that serves Phase 2B was analyzed with the submittal
of Phases 1 B and 1 C. A copy of that report is submitted with this letter. There are no
changes that would significantly alter the system 's performance or change the results of
the previously submitted study.
Sincerely Yours,
~L~
Kent Laza, P .E.
Project Manager
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Sewer System Report
for
Castlerock Subdivision, Phases lA, lB, 1 C, 2A, 2B & 8
College Station, Texas
September, 2006
Revised July 2007
Prepared For:
DDH Investments
4490 Castlegate Drive
College Station, Texas 77845
(979) 690-7250
Prepared By:
Civil Development, Ltd.
2033 Harvey Mitchell Parkway South
College Station, Texas 77840
(979) 764-7743
08-/@(I/
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Cf~rs
808
Locution:
General
Land Use:
Area:
Design Criteria:
GENERAL INFORMATION
The Castlerock Subdivision , Phases I A, I B, IC, 2A, 28 and 8 are located 011 the
south side of SH 40 in southern College Statio n near Castlerock Parkway.
The area encompassed by Phase I B will be served by an existing 18" line that
roughly parallels Spring Creek. This line was installed by the City of College
Station several years ago and was intended to serve the entire area. All 7 lots that
comprise thi s phase have direct access to this line. No additional sewer lines or
manholes will be installed on that system with this project.
Phase IC will involve the extension of 8" and 6" lines from the system that was
built with Phase I A. It will be part of a larger system that will eventually include
Phases 2A, 2B and 8 of the Castl erock Subdivision. This larger system was
analyzed with the development of Phase IA. Since that time, the system has
changed slightly to divide the original Phase 18 into Phase 18 & 1 C. This analysis
incorporates the changes since the original analysis was prepared.
Phase 18 Commercial A-P
Phase 1 C (and all others) Single Family Residential
Phase 1 A (existing) = 13.4 ac. 30 lots
Phase 18 3.6 ac . 7 lots
Phase IC 2.7 ac. 10 lots
Phase 2A (future) 5.9 ac. 33 lots
Phase 28 (future) 8.6 ac. 27 lots
Phase 8 (future) 6.7 ac. 36 lots
Primmy Sewer Outfall: 18" sewer line along Spring Creek (Phase 18)
21" sewer line along Spring Creek (Phases 1 A, 1 C, 2A, 28 & 8)
Commercial Demand (Phase 1 B):
Avg. Pop Density: 30 people per acre
Average Flow: 50 gpd/cap
Peaking Factor: 4
Residential Demand (Phase 1 C):
Avg. Pop Density: 2.67 people per lot
Average Flow: 100 gpd/cap or 267 gpd per lot
Peaking Factor: 4
P1j;e: PVC D3034 SDR 26
Applicable Exhibits:
Conclusion:
Exhibit A -Sanitary Sewer System Schematic
Exhibit 8 -Sanitary Sewer Analysis Spreadsheet
The existing 18" line that will serve Phase 18 was designed to include the flow
from the area. This large line will easily handle the small flowrate from this
development.
The sewer system for Phases I A, IC, 2A, 28 and 8 of the Castle gate Subdivision,
consists of a series of 6" and 8" lines that tie to the city's 21" trunk line along
Spring Creek. The analysis in Exhibit 8 checks the calculated slope required to pass
the estimated fl ow against the minimum slope required by TCEQ. The spreadsheet
indicates the minimum req uired slope is much greater than the computed slope, so
we conclucle th at the system is more than capable of carryi ng the anti cipated flows
l"rom the development.
'. l
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I ' I
Exhibit B
Castlerock Subdivision -Phases lA, lB, lC, 2, 2A and 8
Sanitary Sewer Analysis
Line Flow Calculations Pipe Calculations
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(;i v (.) From To c t;: "-v 0 "O
Cl) v : er::: i
i I I
v "O 0 z v E -o 0 0 '-z
[J.. 8
?;
0
[J..
i !
I ! 1
I Infiltration Peaking Ii
j (10% ADF) Factor
I I
I I
Peak
Flows
l
Size Material
(in.) I I Inches
267 GPO per I I I ! I
MH # MH # GPO/lot ! Person I GPO CFS I I CFS I
I
Slope
Peak
Flows
%
i i !
!
:
i I
Min.
·~ ..
Design Pipe
Slope , Slope
Peak : Check
Flows
%
8 D3034 7.754
Outfall #1 -Serves Phase IA, IC, 2, 2A and 8 I I !
s 1 · --I.f_J_ ____ 36 __ . ' o __ j 9,612 ______ -__ _,_I._-_-_-9=,6::::1_2--+-+ _-o::::._o-1::::4::::9::::~--o-.o-o-1-5-+--4-.o-o-+---o.-06 __ , __ -l-----+------+i-0.-0-03-0--'-1 _o_.4_0 ____ :~~-0K--
1 c 2 _J_c_1 _____ ~ _____ '. __ _9 _____ _!_ ___ !_}_3_5 ---:----~ 1,335 o.0021 __ J_ 0.0002 4.oo 0.01 I 0.0003 ~_o_.8_o _____ o_K_ 6 D3034 5.793
8 D3034 7.754
8 I D3034 7.754
IC I 11:_2 _ ---~---, __ 0 _____ ; ______ 8_~!----10,9~?--~ 11,748 1 0.0182 T_ 0.0018 I 4.00 ! 0.07 ! 0.0045 j 0.40 __ . __ O_K_
IA I IA2 _ --28 -,_ ____ o _____ 7_,_476 _; ________ : ___ _L ___ 7,4761 0.0116 _ _1_ __ _2.0012 ____ 4 .0~_o_.0_5 ___ , __ __,_ __ ~ ______ ! 0.001 8 0.40 OK ---------------
8 I 03034 7.754
8 D3034 7.754
8 D3034 7.754
I A3 3 0 80 I -19,224 : 20,025 I 0.0310 J__ 0.0031 4.00 ' 0.13
_?1·_:~ __ j _3 ___ :-~-----o~=~~~--8~~1 1 [-------=----r 8,811 0.0136 I 0.0014 4.oo 0.06
IA2
2AI
21
I 0.0130 0.4 0 OK --------· I 0.0025 0.40 OK I -----0.0062 0.40 OK
8 03034 7.754
IA3 19 I 0 5,073 i 8,811 13,884 0.0215 I 0.0021 4.00 0.09 ·-·-----------. ---' --~--------+-----+-----f-------+----+-----•---+---------.----~----l A4 3 0 I 801 : 33 ,909 34,710 0.0537 0.0054 4.00 I 0.22 IA3
I
I
------0.0390 0.40 OK
8 D3034 7.754 --------· ·----·---~----·-·--·-r·----~-----'---+----'--+----+------+-----+----l---+------+------+-----------
22 IA4 _____ 3 __ -+-___ o __ :_. -~------+---8_0 _1 +-o_.0_0_1_2--+--_o_.0_0_0_1_+-_4_.o_o_+-' _o_._0_1 _1 __ +-----+-----,.----;-----
---------·· 0.0000 0.40 OK .... ---
8 D3034 7.754 1 A4 __ 1~~---__ 0 ___ ; __ 9 ______ : __ -1 35,511 ____ 3 __ 5~,5_1 _1 _,__o_._05_4_9 _,__o_.o_o_5_5_+--_4_.o_o_l---o_.2_3 __ , __ _,_ ___ -+------+---~----0.0408 0.40 OK ------
outfall #2 -Serves Phase I Bi ' :
18 D2241 17 .263 1 B 1 ·i_~~--'-o _____ :: =-~~<IT~~-:.~=-----~-~-1 ___ ~,_-__ -3-3-,9-0_9___,l __ 34-,-o9_o_,__o-.o-5-27-_-t,_-_-___ -0::::.0::::0::::5::::3 :::::::::::::::::4_.-0::::0:::::::::~0_ .. _22 __ , __ --'------'------L-----0.0005
Exhibit B
Page I of I
------0.20 OK ----···· -----