HomeMy WebLinkAboutProposed Sanitary Sewer Line ImprovementsDesign Report
Proposed Sanitary Sewer Line Improvements
for
Castlegate Subdivision - Section 7
The Estates of Castlegate
College Station, Texas
March 2004
Prepared By:
TEXCON General Contractors
1707 Graham Road
College Station, Texas 77845
(979) 764-7743
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1.0 INTRODUCTION & DESCRIPTION
The purpose of this report is to provide a description of the proposed sanitary sewer to be
constructed with the Castlegate Subdivision Section 7, The Estates of Castlegate, and to
provide the criteria used in the design of this sanitary sewer system. The project will
include the construction of approximately 1,945 feet of sanitary sewer line. The line will
service the proposed development of the Castlegate Subdivision, Section 7.
2.0 SANITARY SEWER - Design Flow and Pipe Size Calculations
The proposed sewer line is to be constructed of 6" and 8" diameter SDR-26, PVC pipe
which meets the requirements of ASTM-D3034. The proposed manholes are 4' diameter
manholes, and vary from 7' to 11' in depth, with sewer line slopes ranging from 0.6% to
2.330%. The maximum distance between manholes is less than 500 feet, as required by
the Texas Commission on Environmental Quality (TCEQ). The minimum allowable
slopes for 8" and 6" pipes per TCEQ requirements are 0.33% and 0.50%, respectively. All
construction shall meet the current City of College Station Standard Specifications for
Sanitary Sewer Construction. The sewer line information is summarized in Table 1.
3.0 DETERMINATION OF PEAK FLOW VALUES
The peak flows were based on using a daily use of 300 gallons per day for each dwelling
unit. The design peak flow is determined by multiplying the average daily flow by 1.5,
which results in the adjusted daily flow. This value is then multiplied by 3.0 to determine
the peak hourly flow. The velocities for the lines were calculated using Manning's
Equation. According to the TCEQ, the minimum velocity for sewer systems flowing full
is 2.0 feet per second. As shown in Table 1, the minimum anticipated flow velocities for
the proposed sewer lines at 50% full meet this requirement. The flow for 100% full will
not be less than the flow for 50% full; therefore, the TCEQ requirement is met. The TCEQ
requires that the maximum velocity for sewer systems flow full not exceed 10 feet per
second. The values in Table 1 are well below this maximum velocity.
TABLE 1 - SEWER LINE FLOW DATA
O
Manhole
No. of
Units From
Cumulative
Average
Peak Flow
Percent
50% Full
Z
m
Number
Size
Length
Slope
Dwelling Unit
Merging
Dwelling
Daily Flow
Full
Flow
Velocity
From
To
(in)
(ft)
services
Lines
Units
(gpm)
(cfs)
(cfs)
(cfs)
(fps)
Existing
7-1
8
164.9
1
6(S-2)
24
5.00
0.0111
0.0501
13.9
0.6042
3.5
7-1
7-2
6
177.0
r1.30
0
-
17
3.54
0.0079
0.0355
16.0
0.3199
3.3
7-2
7-3
6
156.8
4
-
17
3.54
0.0079
0.0355
16.0
0.3199
3.3
N
7-3
7-4
6
225.3
1.10
1
13
2.71
0.0060
0.0271
14.6
0.2942
3.0
74
7-5
6
278.0
1.18
4
-
12
2.50
0.0056
0.0251
14.0
0.3048
3.1
7-5
7-6
6
382.9
0.60
8
-
8
1.67
0.0037
0.0167
13.4
0.2173
2.2
N
7-1
7-7
6
395.1
0.80
2
-
6
1.25
0.0028
0.0125
10.9
0.2509
2.6
N
7-7
7-8
6
161.5
2.33
4
-
4
0.83
0.0019
0.0084
7.0
0.4282
4.4
n = 0.013
Refer to construction drawings for manhole locations.
4.0 CONCLUSIONS
It is our determination based on the criteria and data developed that the proposed sewer
line will provide sufficient capacity for the anticipated wastewater flows generated by this
development.
Design Report
Proposed Sanitary Sewer Line Improvements
for
Castlegate Subdivision - Section 7
The Estates of Castlegate
College Station, Texas
March 2004
Prepared By:
TEXCON General Contractors
1707 Graham Road
College Station, Texas 77845
(979) 764-7743
•
.1 009...•••URSO
GINGER L. U
00
!cF t4
1.0 INTRODUCTION & DESCRIPTION
The purpose of this report is to provide a description of the proposed sanitary sewer to be
constructed with the Castlegate Subdivision Section 7, The Estates of Castlegate, and to
provide the criteria used in the design of this sanitary sewer system. The project will
include the construction of approximately 1,945 feet of sanitary sewer line. The line will
service the proposed development of the Castlegate Subdivision, Section 7.
2.0 SANITARY SEWER - Design Flow and Pipe Size Calculations
The proposed sewer line is to be constructed of 6" and 8" diameter SDR-26, PVC pipe
which meets the requirements of ASTM-133034. The proposed manholes are 4' diameter
manholes, and vary from 7' to 11' in depth, with sewer line slopes ranging from 0.6% to
2.330%. The maximum distance between manholes is less than 500 feet, as required by
the Texas Commission on Environmental Quality (TCEQ). The minimum allowable
slopes for 8" and 6" pipes per TCEQ requirements are 0.33% and 0.50%, respectively. All
construction shall meet the current City of College Station Standard Specifications for
Sanitary Sewer Construction. The sewer line information is summarized in Table 1.
3.0 DETERMINATION OF PEAK FLOW VALUES
The peak flows were based on using a daily use of 300 gallons per day for each dwelling
unit. The design peak flow is determined by multiplying the average daily flow by 1.5,
which results in the adjusted daily flow. This value is then multiplied by 3.0 to determine
the peak hourly flow. The velocities for the lines were calculated using Manning's
Equation. According to the TCEQ, the minimum velocity for sewer systems flowing full
is 2.0 feet per second. As shown in Table 1, the minimum anticipated flow velocities for
the proposed sewer lines at 50% full meet this requirement. The flow for 100% full will
not be less than the flow for 50% full; therefore, the TCEQ requirement is met. The TCEQ
requires that the maximum velocity for sewer systems flow full not exceed 10 feet per
second. The values in Table 1 are well below this maximum velocity.
TABLE 1 - SEWER LINE FLOW DATA
o
Z
Manhole
No. of
Units From
Cumulative
Average
Peak Flow
Percent
50% Full
Number
Size
Length
Slope
Dwelling Unit
Merging
Dwelling
Daily Flow
Full
Flow
Velocity
J
From
To
(in)
(ft)
Services
Lines
Units
(gpm)
(cfs)
(cfs)
(cfs)
(fps)
Existing
7-1
8
164.9
1.00
1
B (S-2)
24
5.00
0.0111
0.0501
13.9
0.6042
3.5
7-1
7-2
6
177.0
1.30
0
17
3.54
0.0079
0.0355
16.0
0.3199
3.3
7-2
7-3
6
156.8
1.30
4
17
3.54
0.0079
0.0355
16.0
0.3199
3.3
N
7-3
7-4
6
225.3
1.10
1
13
2.71
0.0060
0.0271
14.6
0.2942
3.0
7-4
7-5
6
278.0
1.18
4
12
2.50
0.0056
0.0251
14.0
0.3048
3.1
7-5
7-6
6
382.9
0.60
8
8
1.67
0.0037
0.0167
13.4
0.2173
2.2
N
7-1
7-7
6
395.1
0.80
2
6
1.25
0.0028
0.0125
10.9
0.2509
2.6
to
7-7
7-8
6
161.5
2.33
4
4
0.83
0.0019
0.0084
7.0
0.4282
4.4
n = 0.013
Refer to construction drawings for manhole locations.
4.0 CONCLUSIONS
It is our determination based on the criteria and data developed that the proposed sewer
line will provide sufficient capacity for the anticipated wastewater flows generated by this
development.