HomeMy WebLinkAboutSewer System ReportSewer System Report
for
Castlerock Subdivision, Phases lA, lB, lC, 2A, 2B & 8
College Station, Texas
September, 2006
R evised July 2007
Prepared For:
DDH Investments
4490 Castlegate Drive
Coll ege Station, Texas 77845
(979) 690-7250
Prepared By:
Civil Development, Ltd.
2033 Harvey Mitchell Parkway South
College Station, Texas 77840
(979) 764-7743
Loco lion:
General
land Use:
Area:
Design Criteria:
GENERAL INFORMATION
The Castlerock Subdivision, Phases I A, J B, JC, 2A, 2B and 8 are located on the
south side of SH 40 in southern College Station near Castl erock Parkway.
The area encompassed by Phase 1 B will be served by an existing 18" line that
roughly parallels Spring Creek. Thi s 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 this phase have direct access to this line. No additional sewer lines or
manholes will be installed on that system with this project.
Phase lC will involve the extension of 8" and 6" lines from the system that was
built with Phase 1 A. It will be part of a larger system that will eventually include
Phases 2A, 2B and 8 of the Castlerock 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 1 B into Phase 1 B & 1 C. This analysis
incorporates the changes since the original analysis was prepared.
Phase 18 Conm1ercial A-P
Phase 1 C (and all others) Single Family Residential
Phase I A (existing) = 13.4 ac. 30 lots
Phase 1 B 3.6 ac. 7 Jots
Phase IC 2.7 ac. 10 lots
Phase 2A (future) 5.9 ac . 33 lots
Phase 2B (future) 8.6 ac. 27 lots
Phase 8 (future) 6.7 ac. 36 lots
Primary Sewer Outfall: 18" sewer line along Spring Creek (Phase 1 B)
2 1" sewer line along Spring Creek (Phases 1 A, 1 C, 2A, 28 & 8)
Commercial Demand (Phase J 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
Pipe. PVC D3034 SDR 26
Applicable Exhibits:
Conclusion:
Exhibit A -Sanit ary Sewer System Schemati c
Exhibit 8 -Sanitary Sewer Analysis Spreadsheet
The existing 18" line that will serve Phase I 8 was designed to include the flow
fr om the area. This large line will easil y handle the small flowrate from this
development.
The sewer system for Phases 1 A, 1 C, 2A, 28 and 8 of the Castlegate Subdivision,
consists of a series of 6" and 8" lines that tie to the city's 21" trunk lin e 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 required slope is much greater than the computed slope, so
we conclude that the system is more than capable of carrying the anticipated flows
from the development.
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SEWER SCH EMATIC
EX HIBIT
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Line
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0 "O 0 ....:i z <!) (rj <!) E -o u From To c !..:: 0 0 ....... .... z <!) 0 u... "O E ~ C/l ' <!) 0 ~ I u... '
267 GPO per !
MH# MH # GPO/lot Person I GPO
Outfall #I -~erves Phase 1~, tC,_b}A and 8
SI IC! 36 0 ' 9,6 12 I -----------IC2 !Cl 5 0 1,335 I -----·--IC! IA2 3 0 80 1
Exhibit B
Castlerock Subdivision -Phases lA, lB, lC, 2, 2A and 8
Sanitary Sewer Analysis
Flow Calculations
C/l I <!)
bl) "O I c F= 0 I ·..= 0 z I Average Daily Infiltration Peaking .E <.I: I Peak E Size ·;:::: ~ "' Flows (ADF) i (10% ADF) Factoc
1
Flows c 0 <!) o -1:::: I u u... C/l 0.
:J I
I I
I
I I
I I
I I GPO I CFS CFS I CFS (in.)
I I I -I 9,612 0.0 149 0.00 15 4.00 I 0.06 8 ---· -1,335 0.0021 l_ 0.0002 4.00 I 0.01 6
10,947 I 11,748 0.0 182 T 0.0018 4.00 l 0.07 8
I
'
----·--- -I
IA! IA2 28 0 7,476 .
IA2 IA3 3 0 80 1 ---2AI 21 33 0 8,~l_!__l.. ------21 IA 3 19 0 5,073 ' ----------·-
IA3 JA4 3 0 801 -----22 IA4 3 0 801 I ----------· IA4 !AS 0 0 ---------Outfall #2 -Serves Phase 1 B 182]_0 _ -. ------181 I !Bl 3.61 ----
-7,476 i --19,224 20,025 r--I 8,8 I I -
8,811 I 13,884
33,909 I 34,710
I -801
3s,s 11 I 35,511
I I
33,909 I 34,090
0.0116 I 0.00 12 j
0.0310 0.0031
0.0136 0.0014
0.0215 0.0021
0.0537 0.0054
0.0012 0.000 1
0.0549 0.0055
0.0527 0.0053
Exhibit B
Page I of I
I_ 4.00
4.00
4.00
4.00
4.00
4.00
4.00
4.00
0.05 8 I
0.13 8 I
I 0.06 8
I 0.09 8
! 0.22 8
i 0.01 8
I 0.23 8
I
l 0.22 18
, ..
-·
Pipe Calculations
I
·Manning Min.
Friction Design Pipe Inside Material Slope Slope Slope Diameter Peak Peak Check I
Flows I Flows
I
I I
'
In ches % % I
! ---0 3034 7.754 ' 0.0030 0.40 OK I --
03034 5.793 I 0.0003 0.80 OK --
0 3034 7.754 I 0.0045 0.40 OK ----
0 3034 7.754 I 0.0018 0.40 OK ----
03034 7.754 0.0130 0.40 OK - -----
03034 7.754 I 0.0025 0.40 OK -·--
03034 7.754 I 0.0062 0.40 OK ---
0 3034 7.754 I 0.0390 0.40 OK -03034 7.754 0.0000 0.40 OK -
03034 7.754 0.0408 0.40 OK --
----
02241 17.263 0.0005 : 0.20 OK ---