Draft Infiltration and Inflow Report March 1998L EXECUTIVE SUMMARY AND RECOMMENDED PLAN .....................................I-1
A.
OVERVEW
I-1
B.
SUMMARY OF FINDINGS
....I-1
1. Field Inspection
I-1
2. Capacity Analysis
....I-1
3. Lift Station Pump Performance
....I-1
C.
CONCLUSIONS
....I-1
D.
RECOMMENDATIONS
I-2
II. INTRODUCTION
II-1
A.
GENERAL
...II-1
B.
SCOPE OF STUDY ..............••-............................................................................II-1
C.
LOCATION .........................................................................................................II-2
D.
CLIMATE ............................................................................................................II-2
E.
TOPOGRAPHY ...................................................................................................II-2
F.
GEOLOGY
..II-3
G.
POPULATION
..II-3
H.
PRESENT CONDITIONS
..II-3
1.
EXISTING FACILITIES
..II-4
III. SUR
VEY ACTIVTIES
III-1
A.
GENERAL
I II-1
B.
SOURCE DEFECT IDENTIFICATION
III-1
C.
FIELD TESTING PROCEDURES
III-2
ADS EnVronmental SerVices, Inc.
i
1.
Vsual Manhole and Pipe Inspection III-2
2.
Inventory of the Collection System III-2
3.
Structure Numbering III-3
4.
Manhole Conditions III-5
5.
Source Defect Location III-6
6.
Smoke Testing
III-6
7.
Dye Water Flooding
III-7
8.
Clean and TeleVsion Inspection
III-7
IV. PHYSICAL
INSPECTION DATA AND ANALYSIS
..IV-1
A. DEF
ECT ANALYSIS
..IV-1
1.
Introduction
IV-1
2.
Public Sector Defects
..IV-1
3.
Private Sector Defects
..IV-1
4.
I/I Quantification
..IV-2
B. COS
T ANALYSIS AND RECOMMENDED REHABILITATION
IV-2
1.
Cost of Rehabilitating Problem Line Segments
IV-2
2.
Data Summary
IV-4
C. COL
LECTION SYSTEM MAINTENANCE AND REPAIR
IV-14
1.
Preventive Maintenance
IV-14
2.
Schedule
IV-14
3.
Preventative Maintenance Tasks
IV-15
V. SPECIAL CONSIDERATIONS
V-1
ADS EnVronmental SerVices, Inc.
11
A. DEFECT QUANTIFICATION V-1
B. STORM TO MAINLINE CROSS CONNECTIONS V-2
VI.
C. SPECIAL REHABILITATION CODES
1. Special Line Rehabilitation Codes...........
2. Special Manhole Rehabilitation Codes
D. SPECIAL MANHOLE COVER ITEMS
V-2
V-2
V-3
V-4
1. Missing Covers V-4
2. Storm Covers V-4
E. DEFECTS REQUIRING IMMEDIATE ATTENTION V-4
TERMS AND DEFITIONS .........................................................................................VI-1
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iii
LIST OF TABLES
Table I-1 - Defect Rehabilitation by City Personnel .....................................................................I-3
Table III-1 - Field Survey Activity Summary III-3
Table III-2 - Sewer Pipe Inventory III-4
Table IV-1 - Defect Summary ...................................................................................................IV-2
Table IV-2 - Rehabilitation Methods and Costs IV-5
Table IV-3 - Occunence Summary by Rehabilitation Method .............,..................................IV-10
Table IV-4 - Collection System Maintenance IV-15
Table V-1 - Access Structures with Missing Covers V-5
Table V-2 - Manholes with Storm Covers V-5
Table V-3 - Defects Requiring Immediate Attention V-6
LIST OF FIGURES
Figure III-1 - Collection System Pipe Inventory
Figure III-2 - Manhole 02-0100M Broken Frame
Figure III-3 - Typical Smoke Defect
Figure IV-1 - Breakdown of Defects
III-4
III-6
III-6
IV-13
ADS EnVronmental SerVices, Inc.
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APPENDICES
A- Wastewater Collection System Capacity Analysis (Not Included)
B- Rehabilitation Cost Analysis By Manhole and Line Segments (Included)
C- Rehabilitation Cost Analysis and Cost Analysis Summary (Included)
D- Line and Manhole Condition (Included)
E- Television Inspection Logs and Tapes (Not Included)
F- Physical Inspection and Smoke Testing Field Forms (Not Included)
ADS EnVronmental SerVces, Inc.
v
I. EXECUTIVE SUMMARY AND RECOMMENDED PLAN
A. Overview
The primary purpose of the Sanitary Sewer Evaluation Survey was to identify
areas of excessive inflow and infiltration into the City of Paris wastewater
collection system. This report will present all findings from the SSES of the
system, along with recommendations for rehabilitation of defects and sub-
standard appurtenances. B. Summary of Findings
1. Field Inspection
Approximately 7,000 defects were located through physical inspection,
smoke testing, dyed water testing, and television inspection.
Rehabilitation of public sector defects is estimated to cost approximately
$8,000,000, and 53% of this cost is associated with mainline point repairs,
lining, and replacement. As part of the field inspection activities, all
structures were numbered.
2. Capacity Analysis
Results of the hydraulic model will be presented in Appendix A.
3. Lift Station Pump Performance
Results of the 41ift station pump performance tests will be presented in a
separate letter report.
C. Conclusions
The following aze the conclusions reached by ADS based on all collected data and
available information:
ADS Environmental Services, Inc.
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• Parts of the system are in an advanced state of disrepair, with numerous
deteriorated manholes and lines, as well as structural failures.
• Numerous tees and end-of-line segments in the collection system make
proper system maintenance difficult.
~ An annual preventative maintenance schedule would alleviate sewer backups
in areas were they occur.
D. Recommendations
The following activities should be undertaken as part of an overall plan to
improve the city of Paris' wastewater collection and transmission system and
reduce wet weather overflows:
9L
• Perform additional investigations, as outlined in Sectione of this report, to
determine appropriate rehabilitation for defects not yet televised or dye
tested.
• Repair a11 public and private sector defects located through field
investigations.
• Conclude smoke testing on the entire collection system.
0 Incorporate hydraulic capacity improvement recommendations determined by
the hydraulic model into the overall rehabilitation plan.
• Conduct post-rehabilitation flow monitoring to determine effectiveness of
rehabilitation and reassess the condition of the collection system.
• Update the hydraulic model on an annual basis, using data collected from the
permanent flow monitors.
ADS Environmental Services, Inc.
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Establish a permanent maintenance program, including regular cleaning,
televising, and surface inspection, as detailed in Section IV of this report.
This program will cost a total of approximately $1,000,000 per annum.
Undertake rehabilitation of the defects listed in the following table with city
personnel:
Table I-1. Defect Rehabilitation by City Personnel
Manhole Rehab
Total
Occurrences
I/I
Quantified
(GPD)
- I/I
Removable
(GPD)
Rehab Cost
Insta.ll Inflow Dish
109
30,629
27,578
23,980
Install Lid Gasket
4
1,152
1,036
660
Replace Manhole Cover
15
3,542
3,187
3,750
Replace Manhole Cover
Missing Bolts
107
21,024
18,907
17,655
Install New Manhole Frame
and Cover - Standard
349
300,345
270,279
243,120
Install New Manhole Frame
and Cover- Raise to Grade
28
16,546
14,889
27,720
Raise Manhole to Grade
17
1,325
1,192
12,740
Seal Casting-to-Chimney
322
107,337
96,540
147,260
Seal Casting-to-Cone
158
51,221
46,068
68,290
Rebuild Manhole Chimney
105
90,936
81,832
112,980
Replace End-of-Line or
Cleanout w/New Cleanout
677
20,911
18,820
899,000
Total
1,891
644,968
580,328
1,577,155
(Rehabilitation costs shown above are based on estimated contractor costs and
completing these repairs with city personnel would avoid the additional costs of
outside contracting)
ADS Environmental Services, Inc.
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II. INTRODUCTION
A. General
A sanitary collection system of any size is a public investment which requires
constant attention through maintenance and repair to ensure protection of the
environment and public safety, as well as continued economic growth. Providing
for the environment, the public, and growth is a task for which municipalities must
allow resources to continually maintain a collection system's intended
performance. To optimize resources, a collection system must be investigated
thoroughly and systematically to isolate sources of Inflow/Infiltration (UI), locate
structural deficiencies, and identify hydraulic capacity limitations. Following a
systematic investigation of locating UI sources and structural defects, a
recommended rehabilitation plan involving I/I source abatement can be established
to reduce surcharging and overflows within the collection system.
B. Scope of Study
This project is the outcome of an eazlier Flow Monitoring Study carried out by
ADS Environmental Services in October 1996 for the city of Paris, Texas. Based
on previous data and recommendations, the following items are included in the
scope of the current sanitary collection system study:
• Establish a numbering system and assign numbers to all structures (manholes,
pump stations etc.) in the collection system.
• Conduct above ground reconnaissance and map verification, and an inventory
of all access structures including dimensions, construction materials and
physical condition.
Locate, evaluate, and quantify inflow/infiltration sources using methods such
as: physical inspection, smoke testing, dye water testing, and internal closed
circuit television inspection.
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• Lift Station Pump Performance Testing.
• Survey location of approximately 400 manholes for the Hydraulic Model.
• Hydraulic Modeling of the collection system (10" diameter and greater) with
HYDRAO.
• Provide recommendations for rehabilitation of Infiltration/Inflow (I/I) source
defects in the sanitary collection system in an effort to reduce overflows and
bypasses into surrounding receiving waters.
• Provide information for use in addressing Administrative Order issued by
the EPA in (month, yeaz).
• Installation of five (5) permanent flow meters and five (5) rain gauges, and;
C. Location
The City of Paris, which is the seat of Lamar County, is located in northeastern
Texas at the intersection of Highway 82 (East-West) and Highway 271 (North-
South), between the north and south forks of the Sulphur River. Longitude and
latitude are 33.667 north and 95.548 west, respectively.
D. Climate
The climate in the Lamaz County azea can be characterized by relatively mild
winters and hot summers. Tropical maritime air masses flow through the azea in
late spring, su.mmer and early fall, and polaz air masses frequent the area in winter.
Rainfall is abundant and is distributed throughout the year. The mean annual
precipitation is approximately 45.32 inches.
E. Topography
The elevation in Lamar County and it neighboring Delta County range from about
335 feet above sea level in the southeastern part of the area to about 620 feet on the
ADS Environmental Services, Inc.
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highest watershed divides. In the City of Paris specifically, 80% of the terrain is
nearly level to strongly sloping, while the remaining 20% is nearly level to gently
sloping. The area is dissected by many well-defined drainage ways. The area to the
north of Paris drains northeast into the Red River. To the south of Paris, the water
drains southeast into North Sulphur River. Approximately 42 percent of the area is
used for pasture and hay, 33 percent for crops, 13 percent for woodlands, 4 percent
for range, and 8 percent for urban land, federal military land and water area.
F. Geology
In the City of Paris, approximately 80% of the soils and sub-soils consist of
Annona, Freestone and Woodtell types. The remaining 20% is predominantly
made up of Wilson, Normangee and Crockett soil types. Soil permeability ranges
from slowly permeable to very slowly permeable. These properties generally
reduce the effects of long-term infiltration, but at the same time these soil types
have a tendency to magnify inflow intensity.
G. PopulaNon
The population of Paris, according to the 1990 U. S. census, was 24,699 persons.
In the same yeaz, the population of Lamar County was recorded at 43,949 persons.
H. Present Conditions
The Flow Monitoring Study conducted by ADS in October 1996 determined that
the infrastructure decay of the City of Paris resulted in excessive inflow and
infiltration, deficient wet weather and dry weather capacities, as well as overflows,
in more that half of the basins monitored. Rainfall resulted in surchazge and
backwater conditions at ten monitoring sites. The current sanitary collection
system is composed of both gravity and force mainline collection pipes. The
materials utilized for the construction of the force mains include PVC and cast iron
pipe. Gravity mains in the collection system are constructed of vitrified clay, PVC
ADS Environmental Services, Inc.
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and cast iron and range from 6 inches to 27 inches in diameter. In general, service
lines are 4 inches in diameter.
1. Existing Facilities
The existing wastewater collection system studied by ADS consists of 968,741
linear feet of collection line, 928,939 linear feet being gravity mains, and 39,802
lineaz feet being force mains. There are a total of 2653 access structures that
include 1624 manholes, 123 cleanouts, 144 tees, 748 end-of-line structures, and 14
pump stations. The majority of the collection system is composed of 6" and 8"
pipes. Sewage generally flows northerly to the city's wastewater treatment plant.
ADS Environmental Services, Inc.
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III. PHYSICAL INSPECTION ACTIVITIES
A. Introduction
The purpose of the source defect location and identification portion of the Sewer
System Evaluation Survey (SSES) is to locate extraneous water entering (leaking)
into the sanitary collection system and determine, through a cost efficient analysis,
a systematic approach of eliminating defects. The cost efflicient analysis consists
of determining priority numbers for defects based on their estimated I/I contribution
divided by rehabilitation cost, thereby producing a priority ranking. Extraneous
water enters the system through vazious sources such as broken pipe, deteriorated
manholes, cracked service lines, and storm/sanitary collection system cross
connections. Source defect identification tasks determine the locations where
extraneous water enters the system. The source defect location methods used in
this study include: (1) visual manhole and pipe inspection, (2) smoke testing, (3)
dyed water flooding, and (4) internal television inspection.
B. Source Defect Identification
Source defects are those defects or imperfections in the collection system which
allow either groundwater or storm water run-off to enter the collection system. The
location and severity of the defect determines the amount of I/I that enters the
system and the duration over which the extraneous flow affects the system.
The collection system defects are separated into two categories. The first, public
sector defects, are typically maintained by the municipality and include defects
found at manholes, on mainlines, and on municipal service lines. Manhole defects
include those found in the manhole structure. Examples of such defects include
leaks at the manhole cone joints and offset manhole frames. Mainline defects
include those found in the collection system mainlines. Examples of such defects
include cracks, offset joints, and faulty mainline taps. Municipal service defects
include those found between the mainline and the property line on service lines.
ADS Environmental Services, Inc.
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Examples of such defects include broken clean-outs and breaks in the service line.
The second major category, private sector defects, are those found on private
property. Examples of such defects include broken clean-outs, illegal roof drain
connections, and defective service lines. The following section provides a
summary of the field procedures used to identify the source defects.
C. Field Testing Procedures
1. Visual Manhole and Pipe Inspection
Of the targeted 2639 system inspection points in the collection system,
Visual inspections were performed on 1468 manholes. There were 20
buried manholes, 28 surcharged manholes, 94 manholes that could not be
located, and 14 manholes that could not be opened. Additional structures
included 123 cleanouts, 748 end-of-line segments, and 144 tees. Of the 123
cleanouts, 101 were inspected. Each manhole and the pipelines entering the
manhole were inspected with the use of strong artificial light or reflected
sunlight. The photographs that were taken to record the conditions
encountered provided two significant functions: (1) a visual inventory of the
structures, and (2) the location and description of the observed defects. The
manhole and mainline inspection data, including the photographs, are
included in Appendix F.
2. Inventory of the Collection System
Out of a total system footage of 968,741 linear feet of sanitary sewage pipe,
field representatives performed inspections on 928,9391inear feet. The
collected data was used to create a database on the physical characteristics
of the system, and to provide information to assist during the rehabilitation
phase of the project. A complete pipe inventory for the Paris collection
system is provided in Table III-l, page III-4, and is shown in graphical
format in Figure III-1, on page III-4.
ADS Environmental Services, Inc.
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3. Structure Numbering
Each node in the Paris collection system has been numbered. A node is
defined as a manhole, in-line clean-out, end of line clean-out, end of line
segment, in-line tee, or in-line reducer.
Table III-1 - Field Survey Activity Summary
Ph sicalIns ection
Manholes Internally Inspected
1,468
Could Not Locate
94
Could Not Open
14
Surcharged
28
Buried
20
Clean-out
101
End of Line
748
Tee
114
Smoke Testin
Actual Smoke Tested Length
513,661
Total Not Smoke Tested
455,110
Television Ins ection
Total Possible Footage
82,774
Actual Televised Footage
52,800
ADS Environmental Services, Inc.
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Figure III-1 - Sewer Pipe Inventory
m 22,471
O 505,359
• 24,332
• 12,287
O 8,228
G 10,676
■ 14,056
■ 51,221
■ 56,398
Pipe Diameter
■4 06 ■8 ■10 ■12
■15 ~I8 021 ■24 ■27
■ 223,911
Table III-2
Sewer Pipe Inventory
Paris, TX. Sewer System Evaluation Study
Line
Diameter
Number of
Segments
Total Line
Length
Inch-Dia-
Miles
4
88
22,471
17.0
6
1,500
505,359
574.3
8
644
223,911
339.3
10
178
56,398
106.8
12
135
51,221
116.4
15
31
14,056
39.9
18
30
10,676
36.4
21
14
8,228
32.7
24
24
12,287
55.9
27
17
24,332
124.4
Total
2,644
928,939
1,443.1
III-4
4. Manhole Conditions
Each point of access was inspected and the following information was
recorded on Field Survey Forms and then entered into a database for
subsequent computer analysis.
Manhole Data
• Construction materials and conditions of covers, rings, walls,
steps, benches and channels
• Manhole depth and opening size
• Number of holes in cover
• Manhole address
• Level of high water mazk in manhole
• Type and depth of debris
• Special problems and conditions such as sources of inflow,
bypasses, and manholes located in natural ponding areas
Line Data
• Size, type, length and depth of each line entering the manhole
• Root growth in pipe
• Depth of deposition in pipe
• Structural condition of pipe
Summarized results of the visual inspection can be found in Appendix D
(Manhole and Line Condition Reports). Field inspection data and
photographs are included in Appendix F.
ADS Environmental Services, Inc.
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5. Source Defect Location
All defects located (cracked manhole walls, broken pipe seals, leaking
frame seals, etc.) were recorded
on field inspection forms. To the
left, in Figure III-2, is a
photograph of a broken frame.
Photographs like this one, and the
one below, were taken of all
defects observed and are included
Figure III-2 - Manhole 02-0100M with
Broken Frame
6. Smoke TesNng
with the field inspection data in
Appendix F.
Smoke testing of a sanitary collection system is an effective means to detect
sources of inflow and restrictive conditions. Smoke testing was conducted
on approximately 513,660
linear feet of pipeline. During
performance of this task, smoke
was introduced into line
segments and service laterals.
Where smoke escaped, leaks
were recorded with color
photographs, I/I flow rates were
estimated, and sketches were
prepared which referenced each
leak to two permanent markers. Figure III-3 shows smoke exiting through
a mainline defect. The sketches and field notes for each defect are included
in Appendix F. Leak rates assigned to each defect are based on the field
ADS Environmental Services, Inc.
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observations and estimates of the size of the drainage area tributary to the
defect.
7. Dye Water Flooding
Dye flooding was performed at 135 locations in conjunction with internal
television inspection to locate line defects associated with specific smoke
leaks. Dye flooding was performed by introducing fluorescent dye into
potential inflow sources through ponding areas, and-then visually
monitoring the flows from adjacent collection system lines for signs of dyed
water as an indication of inflow. Each leak identified during the dye
flooding procedure was assigned an estimated flow rate. Dye tests
performed are included in Appendix F with the internal television logs.
8. Clean and Television Inspection
Internal television (TV) recommendations were based on findings observed
during the visual inspection and smoke testing phases of the survey
activities. Collection system lines that had major defects such as cracked
pipe, offset joints, and mainline smoke defects were concluded to require
TV inspection to pinpoint the defects, ascertain their extent and magnitude,
determine possible I/I sources, and help develop appropriate repair methods.
Hydraulic cleaning and internal TV inspections were performed on
approximately 53,000 lineaz feet of pipe. A closed circuit TV camera was
guided through the pipe and conditions and defects were observed and
recorded on logs. T'hese logs and a tape index are included in Appendix F.
TV inspection videotapes are also included separately from this report.
ADS Environmental Services, Inc.
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IV. PHYSICAL INSPECTION DATA AND ANALYSIS
A. Defect Analysis
1. Introduction
This section describes the types of defects located during the field investigations
of the Paris wastewater collection system. Table IV-1, p4ge IV-2 summarizes the
defect totals, I/I quantified for the defects, and the estimated rehabilitation costs
by defect category. These totals include both maintenance and I/I related defects.
2. Public Sector Defects
Public sector structural defects and I/I source defects are associated with
manholes, mainlines, and municipal service lines. A total of 4,321 manhole,
2,029 mainline, and 207 municipal service line defects were identified during the
study. The majority of mainline defects are associated with mainline point repairs,
replacement of mainlines, and minor defects requiring scheduled maintenance and
repairs. The total estimated rehabilitation cost for public sector defects is
approximately $8,000,000.
3. Private Sector Defects
Private sector defects accounted for 580 of the defects identified in the study.
Defects associated with cleanouts and breaks in the service line account for the
majority of needed repairs. It is important that the private sector defects be
addressed and then properly repaired for a successful comprehensive I/I reduction
program. The total estimated repair cost associated with private sector defects is
approximately $205,000.
ADS Environmental Services, Inc.
IV-1
consideration soil conditions, existing underground utilities, high water tables or
excessive rock excavation.
The PIPE° computer model was used to rank each defect by priority number
(Appendix C). The priority number was determined by dividing the gallons of I/I
eliminated by the estimated rehabilitation cost. It should be emphasized that this
priority number is based on the amount of I/I observed or.expected to enter
through the defect. Although structural defects may not currently contribute I/I,
and as such their priority number will be zero, they may impact the capacity of
existing lines and/or maintenance costs and aze recommended to be included in an
overall rehabilitation program. -
A prioritized ranking was determined for each individual manhole and line
segment based on the total I/I removed divided by the total rehabilitation cost for
that structure, assuming that all defects aze repaired. Appendix B provides
priorirization of each manhole and line segment from the highest rank to the
lowest rank. Also, a prioritization of each manhole and line segment is included
based on the highest I/I removal to the lowest.
Presented for each identified problem is a method of rehabilitation and its
estimated cost (refer to the "Rehabilitation Methods and Costs", Table IV-2, page
IV-5). In addition, each defect in the priority number rankings (Appendix B and
C) can be identified in the field notes (Appendix E) by reference to the upstream
manhole number and sub-basin.
ADS Environmentat Services, Inc.
IV-3
2. Data Summary
The source defect analysis results are summarized in Table IV-3 and Figure IV-l.
Table IV-3 - Rehabilitation Occurrence Summarv
The 7,137 I/I and structural defects account for a total of more than $8,000,000 in
rehabilitation costs (Table IV-3, page IV-10). This cost does not include
engineering, maintenance, or contingency costs.
Figure IV-1 - Breakdown of Defects
Figure IV-l, page IV-13 presents the cost breakdown between public defects
(manhole, mainline and municipal service line) and private service line defects for
the system. The top chart represents the number of occurrences divided into
manhole, mainline, municipal service line, and private service line defects. The
second represents the costs associated with these categories. As can be seen from
the graphs, roughly 61% (4,321 defects) of the total occurrences (7,137 defects)
are located in manholes, and the total cost to repair these defects represents
approximately 43% of the total rehabilitation costs. The mainline defects
comprise 28% (2,029 defects) of the total with a cost greater than $4,400,000 to
repair, and the total cost to repair these defects represents around 53% of the total
rehabilitation costs.
ADS Environmental Services, Inc.
IV-4
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Table IV-2 (cont.)
Rehabilitation Methods and Costs
Paris, TX. Sanitarv Sewer Evaluation Studv
Line Replacement Costs/Foot
Diameter Pipe Depth - Upaved
(in) 0-6 6.1-8 8.1-10 10.1-12 12.1-14 14.1-16 16.1-20
6
53
53
111
135
164
202
245
8
53
53
111
135
164
202
245
10
56
56
114
138
167
205
248
12
56
56
117
141
170
208
251
15
59
59
121
145
175
212
255
18
67
67
126
149
179
216
260
21
61
61
120
143
173
210
254
24
70
70
128
152
182
219
266
27
70
70
128
152
182
`219
266
30
78
78
137
161
191
228
272
33
78
78
137
161
191
228
272
36
87
87
145
169
199
237
281
42
96
96
154
178
208
246
292
48
107
107
165
189
219
257
300
54
232
232
290
314
344
382
430
60
272
272
330
354
384
422
486
66
304
304
362
386
416
454
496
72
345
403
428
458
496
540
78
390
448
473
503
541
586
84
516
546
585
629
90
569
600
638
683
96
620
650
689
734
108
771
809
855
120
1031
1078
Line Replacement Costs/Foot
Diameter Pipe Depth - Paved
(in) 0-6 6.1-8 8.1-10 10.1-12 12.114 14.1-16 16.1-20
6
73
73
131
155
184
222
265
8
73
73
131
155
184
222
265
10
76
76
134
158
187
225
268
12
76
76
137
161
190
228
271
15
79
79
141
165
195
232
275
18
87
87
146
169
199
236
280
21
87
87
146
169
199
236
280
24
96
96
154
178
208
245
292
27
96
96
154
178
208
245
292
30
104
104
163
187
217
254
298
33
104
104
163
187
217
254
298
36
113
113
171
195
225
263
307
42
122
122
180
204
234
272
318
48
138
138
196
220
250
288
331
54
263
263
321
345
375
413
461
60
303
303
361
385
415
453
517
66
340
340
398
422
452
490
532
72
381
439
464
494
532
576
78
426
484
509
539
577
622
84
552
582
621
665
90
605
636
674
719
96
656
686
725
770
108
807
845
891
120
1067
1114
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Table IV-3 Occurence Summary by Rehabilitation Method
Rehab Number of Leak Rate UI Removai Rehab
Leak Entry Method Rehab Description Occurrences (gpd) (gpd) Cost
LINE
40 Minor Defects - Clean, TV [nsp. Line
495
127,296
0
$549,318
41 Minor Defects - Remove Roots, Clean, TV Insp. Line
212
90,864
0
$363,643
43 Mainline Point Repair
190
257,472
180,233
$232,950
44 Mainline Replacement
33
122,688 ,
85,883
$111,743
45 Repair Faulty Mainline Tap
170
82,800
58,004
$147,900
46 Repair MFf/Pipe Connection - Extemal
70
29,808
22,356
$77,225
47 Repair MH/Pipe Connection - Intemal
55
27,504
20,628
$30,250
50 Plug Abandoned Mainline @ Manhole
6
4,608
4,608
$1,650
53 Plug Stubout @ Manhole
29
4,608
4,608
$7,975
54 Line Clean - Medium Deposition
163
0
0
$114,702
55 Line Clean - Heavy Deposition
35
0
0
$19,415
56 Remove Mainline Blockage
45
0
0
$14,850
85 Clean, TV Inspect Line
61
0
0
$68,919
86 Heavy Clean, TV Inspect Line
5
0
0
$17,635
87 Remove Roots, Clean, TV Inspect Line
10
0
0
$14,296
88 Remove Heavy Roots, Clean, TV Inspect Line
1
0
0
$500
401 Minor Defects - CCTV as per Maintenance Schedule
57
117,216
0
$56,987
431 1'V [nsp. Line - Mainline Point Repair
177
164,088
114,842
$411,133
432 Remove Roots, TV Insp.Line - Mainline Point Repair
131
132,552
92,779
$414,188
441 TV Insp. Line - Mainline Replacement
5
9,072
6,350
$20,492
442 Remove Roou, TV Insp.Line - Mainline Replacement
3
7,344
5,141
$9,253
491 Investigate, Repair Suspect StomiM[ain Connection
2
10,800
9,720
$9,650
693 Install Cured-In-Place Liner
27
188,136
150,510
$592,120
696 Replace Entire Mainline
46
605,016
484,013
$1,116,932
751 Investigate Suspect Storm/Svc Connection
1
1,008
0
$2,075
Sub-Total:
2,029
1,982,880
1,239,675
$4,405,800
IV-10
Rehab Number of Leak Rate I/I Removal Rehab
Leak Entry Method Rehab Description Occurrences (gpd) (gpd) Cost
MANHULE
1 Ins[all [nflow Dish @ MH Cover
109
30,629
27,578
$23,980
2 Install MH LidGasket
4
1,152
1,036
$660
4 Replace MH Cover
15
3,542
3,187
$3,750
5 Replace Missing MH Cover Bolts
107
21,024
18,907
$17,655
6 Instal l MH Frame & Cover - Standard
349
300,345
270,279
$243,120
7 Install MH Frame & Cover - Raise MH To Grade
28
16,546 ~
14,889
$27,720
8 Raise MH To Grade
17
1,325
1,192
$12,740
9 Realign & Seal MH Frame
19
6,480
5,828
$7,970
11 Seal Casting-To-Chimney
322
107,337
96,540
$147,260
12 Seal Casting-To-Cone
158
51,221
46,068
$68,290
IS Rebuild MH Chimney
105
90,936
81,832
$112,980
16 Repair Leaks MH Chimney Joinu
184
84,096
63,072
$80,960
17 Repair Leaks MH Chimney Wall
61
21,600
16,200
$23,485
19 Plug Lift Holes [n Precast MH Cone
1
2,304
1,843
$275
21 Repair Leaks MH Cone Joints
15
7,675
5,756
$8,250
22 Repair Leaks MH Cone Wall
52
16,560
12,420
$20,020
25 Plug Lift Holes In Precast MH Sections
4
3,168
2,533
$1,100
26 Repair Leaks - MH Wall
101
38,232
28,674
$55,550
27 Seal Precast MH Joints
479
150,192
112,644
$184,415
28 Remove MH Steps & Seal Holes
109
5,328
4,263
$41,965
30 Install New MH Bench and Channel
lb
3,024
2,723
519,200
31 Repair L.eaks - MH Bench
16
2,880
2,160
$5,280
32 Rebuild MH Channel
76
7,632
5,724
$33,440
33 Repair Leaks - MH Channel
9
864
648
$2,970
34 Remove MH Deposition - Medium
492
0
0
$49,200
35 Remove MH Deposidon - Heavy
80
0
0
$16,000
36 Locate Manhole - Raise To Grade
108
504
0
$94,600
37 Uncover Manhole - Raisc To Grade
18
0
0
$15,560
84 Unidentified Smoke I,eal: - Dye Test Required
6
2,808
0
$2,400
391 Replace Manhole
67
183,066
164,761
$313,000
392 Plug& Waterproof Coat Entire Manhole
237
134,280
100,710
$254,112
394 Replace EOL, Tee or Cleanout w/ Standard Manhole
280
1,584
1,426
$734,000
781 Replace EOL or Cleanout w/ New Cleanout
677
20,911
18,820
$899,000
Sub-Total:
4,321
1,317,245
1,111,713
$3,520,907
IV-11
Rehab
Leak Entry Method Rehab Description
Number of
Occurrences
Leak Rate
(gpd)
UI Removal
(gpd)
Rehab
Cost
MUNICIPAL SERVICE
43 Mainline Point Repair
83
36,144
25,311
$75,650
46 Repair MH/Pipe Connection - Extemai
6
2,592
1,944
$5,900
47 Repair MH/Pipe Connection - Intemal
3
3,024
2,268
$1,650
56 Remove Mainline Blockage
17
0
0
$5,610
70 Disconnect Roof Drains
2
4,032
3,628
$440
72 Plug Abandoned Service u Property Line
2
3,456
, 3,110
$880
73 Point Repair Service Line
16
6,725
6,053
$13,300
74 Service Line Clean - RemoveDeposition
51
• 0
0
$7,650
76 Repair Exposed Service @ Ditch Line
2
2,664
2,398
$880
78 Repair, Replace, Ins[all Cleanout
17
15,423
15,423
$7,480
80 Replace Cleanout Cap/Cover
8
8,640
7,776
$880
Sub-Total:
207
82,700
67,911
$120,320
PRIVATE SERVICE
70 Disconnect Roof Drains
1
2,016
1,814
$220
71 Disconnect Yazd Drain From Service Line
4
7,488
6,738
$1,760
72 Plug Abandoned Service @ Property Line
41
49,104
44,189
$18,040
73 Point Repair Service Line
87
78,051
70,248
$59,100
76 Repair Exposed Service @ Ditch Line
10
13,738
12,366
$4,400
77 Repair Poorty Disconnected Roof Drain
(
2,016
1,411
$275
78 Repair, Replace, Install Cleanout
223
198,782
198,782
$98,120
80 Replace Cleanout Cap/Cover
213
201,662
181,498
$23,430
Sub-Total:
580
552,857
517,046
$205,345
Total:
7,137
3,935,682
2,936,345
$8,252,372
IV-12
Figure IV-1 - Defect Occurrence Summary
Paris, TX. Sanitary Sewer Evaluation Study
Breakdown of Defects
Private Service Manhole
0
Municipal . ~ 60.5%
Service
2.9°/
Mainline
28.4%
_
Total Defects: 7,137 I
Breakdown of Costs
Mainline
$4,405,800
Manhole Municipal
Private Service
$3,520,90'7
- -
Total Costs: $8,252,372 I ernce 120,320
$205,345
IV-13
C. COLLECTION SYSTEM MAINTENANCE AND REPAIR
1. Preventive Maintenance
Preventive maintenance is a program of scheduled inspection, cleaning, and minor
repairs to detect potential problems and prevent their development so that the
collection system is available to the users at all times. An effective program can
prevent failures in the wastewater collection system and save costs of major
reconstruction. It also can avert hazards to public health. This section presents a
preventive maintenance program. It provides a schedule and recommends
intervals for preventive maintenance activities.
2. Schedule
Scheduled maintenance ensures attention to all parts of the system at intervals
frequent enough to discover and correct developing problems before serious
damage results. Periodic inspections promote efficient use of equipment and
manpower through planning. The schedule should consider such factors as the
pipe size, material, type of construction, the normal volume and character of flow,
and possibility of overloads. The service area (residential, business, industrial,
etc.) and equivalent population, past problems or failures, and equipment and size
of crew required should also be considered. Table IV-4 presents a preventive
maintenance schedule for the Paris sanitary collection system.
ADS Environmental Services, Inc.
IV-14
3. Preventive Maintenance Tasks
a) Surface InspecNon
Surface inspection is recommended once every two years for the entire
system. In outlying areas, walking the right-of-way is the most efficient
surface inspection method. The inspector looks for sunken or flooded
areas, ground cracks along pipeline routes, easement encroachment,
evidence of vandalism, and damage to special structures and manholes.
Surface inspection of pipelines along city streets can be made from a
vehicle. The inspector looks for manhole covers above or below the
pavement level and evidence of flooding or seepage from the collection
system. The annual amount inspected will be approximately 500,000 feet,
at a cost of approximately $20,000.
b) Television Inspection
Routine internal television inspection of all pipelines in the system is
recommended once every five years. Whereas television inspection
during the course of this study was defect-oriented, ongoing inspection
will allow for assessment of rehabilitation effectiveness, as well as
pinpoint mains that are leaking or that may leak. The inspection will
ADS Environmental Services, Inc.
IV-15
Table IV-4 - Collection System Maintenance
system which are structurally defective, and require rehabilitation.
Incorporating the television tapes into a central library of system
information will allow the rate of system deterioration over time to be
determined. Annual televised footage will total approximately 200,000
feet, at an estimated approximate cost of $600,000. This cost is based on
typical cleaning and televising costs by a contractor.
c) Cleaning
System-wide cleaning is recommended once every three years. This
schedule does not include any emergency cleaning or blockage removal.
As a part of a preventive maintenance program, scheduled cleaning of the
pipelines seeks to prevent the development of blockages. Blockages may
be physical or hydraulic, so named for their causes. A physical blockage
is caused by a buildup of solidified grease, detergents, or any kind of solid
debris from the wastewater, held in place by some physical defect--a root
mass, a protruding tap, a large crack or break, settled object(s) too heavy
to move with the flow, or a discontinuity because of an offset joint.
Grease can also build up on the wall of the pipe by simple adhesion,
completely obstructing the pipe. A hydraulic blockage results from
inefficient design, where the angle of converging flows causes turbulence,
allowing heavier debris to settle out of the wastewater. The cause of
hydraulic blockages is less often poor original design than later extensions
to accommodate additional tributary azea. In such cases, frequent
scheduled cleaning tends to prevent blockages from developing.
The schedule for routine pipeline cleaning depends on the grade of each
line, the type of area served, and the past history of collection system
performance with the latter being the most important criterion. A pipe laid
at a steep grade with high velocity flow normally presents fewer problems
than one on a flat grade. In residential areas the increased use of garbage
ADS Environmental Services, Inc.
IV-16
grinders and abuse resulting from discarding many "disposable" paper and
plastic products increase the burden on wastewater lines. In factory areas
certain industrial wastes may present a problem. Cleaning will occur on
an estimated 325,000 linear feet of pipe a year, at an estimated cost of
$410,000. This cost is based on typical cleaning costs by a contractor.
ADS Environmental Services, Inc.
IV-17
V. SPECIAL CONSIDERATIONS
A. Defect Quantification
During the course of a field inspection survey, various crews evaluate defects
through several different activities. For example, one crew may see a crack in a
frame seal, and classify it as "minimum". ADS's source defect analysis software,
PIPE, assigns it 0.2 gallons per minute of inflow during a rain event, based on
user-defined quantification tables. During smoke testing, a different crew may
see smoke escaping the frame of the manhole, and classify the defect as "typical",
causing it to be assigned 0.4 gallons per minute of inflow. Neither crew was
necessarily incorrect, but one assigned twice as much inflow as the other.
Furthermore, there may be variances in leak severity assigned by different field
crews for the same defect. While ADS has procedures in place to reduce these
variances, the reality is that they will occur. These examples demonstrate the
inherent flaws in field quantification, no matter what method is used: that humans
use judgment, and judgment can depend on a host of factors, some of which are
controllable, and some of which are not. Methods such as dye testing allow a
much more realistic estimate of actual leak rates to be made, but are cost
prohibitive to perform on every defect.
In addition to this type of error, there is the certainty that not every defect was
found. Finite resources result in a survey that expends enough money to
determine sufficient rehabilitation to reduce overflows, wet weather flows, and
dry weather flows, or achieve whatever the specific objective of the study is.
Flow monitoring typically measures more inflow than is quantified through field
inspection methods, as it measures all inflow except for any bypassed flows.
Typically, 60 to 80 percent of all defects are located through a comprehensive
SSES field investigation.
ADS Environmental Services, Inc.
V-1
B. Storm to Mainline Cross Connections
Two mainline to storm cross connections were not televised and ADS
recommends that these suspected cross connections be dyed water tested and
televised, and has designated rehabilitation code 491 to the defect type. This
rehabilitation code includes the cost to dye, televise, and point repair the defect.
Depending on the severity of the problem as determined through television
inspection, additional rehabilitation for the entire line segment may be necessary,
and this cost is not included. Sejzment 06-0170M - 06-0060M, PS-06 - A suspected storm/mainline smoke
defect was detected at a storm inlet directly in front of the Coca-Cola Bottling
Company of Paris (line length is 120 feet). During the smoke testing procedure,
smoke was observed from both sides of the intersection of 11`' NW St. and
Bonham St. The heaviest of the smoke was observed at the storm inlet.
Segment 10-0420T - 10-0410M, PS-10 - A suspected storm/mainline smoke
defect was detected approximately 356 linear feet downstream of 10-0420T,
which is a tee. The length of the line segment is 4401inear feet.
Another segment, segment 10-0045M -10-0035M, was identified during smoke
testing as a possible storm to mainline cross connection and was televised. After
subsequent analysis of this line segment, it was concluded that the segment would
be lined thereby eliminating the potential storm to mainline cross connection
defect.
C. Special Rehabilitation Codes
1. Special Line Rehabilitation Codes
During the course of the analysis, a need arouse for a grouping of minor
mainline defects that should be watched and eventually repaired, but
which were not as critical to the system condition as other, more severe
defects. Two rehabilitation codes were assigned to these defects: 40 and
ADS Environmental Services, Inc.
V-2
41. If roots were encountered with the defect, a code of 41, which
includes cost for televising and de-rooting, was assigned. A code of 40,
including cost for televising only, was assigned if no roots were found.
No removal of I/I or cost for rehabilitation was assigned to the defects in
either case. I/I quantification from the defects, however, was preserved.
Mainline defects found through manhole inspection (lamping) were
recommended for televising before repair, to avoid unnecessary rework
due to additional defects that might be found farther in the line. Four
rehabilitation codes were created for these defects: 431, 432, 441, and 442.
A rehabilitation code of 431 indicates a point repair(s) with no roots, 432
indicates a point repair(s) with roots, 441 indicates a partial replacement
with no roots, and 442 indicates a partial replacement with roots. These
codes preserve I/I quantification, cost of rehabilitation for the point
repair(s), and include cost to televise the line and de-root, if necessary.
Removal of I/I is the same as for point repair(s) or partial replacement.
2. Special Manhole Rehabilitation Codes
Manhole defects found during smoke testing are typically chazacterized as
either frame defects, frame seal defects, chimney defects, cone defects, or
wall defects. When the analysis is performed, an attempt is made to
correlate the defects detected through smoke testing to those found during
manhole inspection. There are instances, however, where the manhole
appears to be in good condition, yet there is smoke exiting the ground in
the vicinity of the manhole. ADS recommends that these defects be dye
tested to determine the exact nature of the problem, and has assigned a
special rehabilitation code of 84 to designate the defects. It is possible that
some defects may actually be line or service defects that were mistakenly
identified as manhole smoke defects.
ADS Environmental Services, Inc.
V-3
Another rehabilitation code, code 781, has been assigned to address the
large amount of end of line segments and tees found in the collection
system.. This code is used to indicate an end of line or a defective
cleanout is to be replaced with a new cleanout. This would increase the
accessibility to the collection system thereby allowing easier system
maintenance and greater reliability.
D. Special Manhole Cover Items _
1. Missing Covers
Missing covers are listed in the PIPE database as Cover Type - None, and
are listed in Table V-1, page V-5. These covers should be considered
safety hazards, as well as inflow sources, and every effort should be made
to repair them expeditiously.
2. Storm Covers
Storm covers are listed in the PIPE data.base as Cover Type - Storm, and
are listed in Table V-2, page V-5. These covers should be replaced with
standard manhole covers, as they are probable sources of significant
inflow if located in a low lying azea.
E. Defects Requiring Immediate Attention
During the study, a number of defects were found that could, if unattended, cause
serious maintenance problems such as sewer backup into homes, soil settlement,
or other catastrophic failure. Table V-3, page V-5 and V-6, presents severely
broken pipes and offset joints that are stand alone point repairs or are necessary to
accomplish lining of the main and should be repaired immediately. There are
other severely broken pipes and offset joints that are a part of a complete line
replacement project which are not listed in Table V-3, but should also be
accomplished as soon as possible.
ADS Environmental Services, Inc.
V-4
Table V-1. Access Structures With Missing Cover
Paris, TX SSES
Sub-Basin Name
Structure Number
Surface Type
Cover Type
PR-01
01-0065C
Field
None
PR-04
04-0005M
Field
None
PR-06
06-0320M
Asphalt
None
PR-10
10-0310C
Walk
None
PR-10
10-0387C
Yardside
None
PR-17
17-0165C
Yardfront
None
PR-18
18-0525C
Field
None
PR-18
18-0670C
Yardfront
None
PR-20
20-0035M
Field
None
PR-23
23-0592C
Field
None
PR-23
23-0870C
Yardside
None
PR-25
25-0150C
Yazdfront
None
PR-25
25-0415C
Asphalt
None
PR-26
26-0224C
Field
None
PR-26
26-0315C
Yazdfront
None
PR-28
28-0335C
Yardfront
None
PR-29
29-0135C
Field
None
PR-29
29-0140C
Field
None
Table V-2. Manholes With Storm Cover
Paris, TX. SSES
Sub-Basin
Manhole
Surface
Cover Type
PR-26
26-0095M
Asphalt
Storm
PR-26
26-0117M
Walk
Storm
PR-28
28-0165M
Field
Storm
ADS Environmental Services, Inc.
V-5
VI. TERMS & DEEINITIONS
A. Glossary
BASE
A generic term that refers to the bottom of a manhole. It includes portions of the
manhole such as the manhole bench, invert (trough) and bench/wall connection.
CATCH BASIN
A component of a storm system. Catch basins are normally located in a roadside gutter
in order to assist with road drainage. Catch basins are sometimes directly or indirectly
connected to the sanitary system and, therefore, can be a source of UI.
CLEANOUT
A component of a SERVICE or MAINLINE used to insert a cleaning device. It
normally consists of a 4-6 inch steeply sloped vertical pipe that connects a plugged hole
at the surface with the collection line.
DEFECT
A condition in a MAINLINE, SERVICE LINE or MANHOLE such as cracked, broken
or corroded pipe, offset joints, cracked manhole walls or maintenance problems such as
debris/grease that is evidence of collection system degradation. Defects do not
necessarily LEAK.
DEPENDENTSYSTEM
A SUB-BASIN which receives flow measured by one or more flow monitors.
DRAINAGE BASIN
A portion of or entire SANITARY COLLECTION SYSTEM consisting of multiple
mini-systems or SUB-BASINS. DRAINAGE BASINS are normally defined by a
downstream treatment plant, major TRUNK LINE, a creek, or watershed area.
ADS Environmental Services, Inc.
VI-1
DYE D[LUTION
A method of ineasuring instantaneous flow which consists of injecting a known quantity
of dye into the system and computing the concentration of dye downstream. The more
diluted the concentration is the greater the flow quantity.
DYE TESTING
A rainfall simulation technique used to more accurately locate and quantify inflow
sources identified during smoke testing. The method is typically used on storm system
sections, ditch sections, stream sections, and on potential mainline defects. Possible
leaks are flooded with dye in order to simulate a storm event whereby the manhole
immediately downstream is observed for evidence of dye. This can also be performed
during a storm event and is normally done in conjunction with TV TESTING.
EVIDENCE
It is not always possible to observe a DEFECT to be actually leaking. However, stains,
mud, mineral deposits, sand, etc., may indicate that a DEFECT will leak under
appropriate conditions. These conditions aze considered to be evidence.
EXTRANEOUS
Another term for UI. It describes extra flow other than domestic sewage that enters a
sanitary collection system through leaking DEFECTS.
FLOW ISOLATION
The process by which SUB-BASIN INFILTRATION is "isolated" within a smaller
portion of the sanitary collection system. Its purpose is to identify portions of the
collection system subject to possibly excessive infiltration, typically, in order to
designate lines needing subsequent cleaning and internal television inspection. This is
accomplished by measuring flow during periods of minimum sewage contribution
normally between midnight and 6:00 AM with WEIRS, at one point in time, and
subtracting any upstream contribution.
ADS Environmental Services, Inc.
VI-2
GROUNDWATER
Water that exists under the ground on a more or less continuous basis. The level of
groundwater is higher or lower depending upon the season of the year and rainfall. If
groundwater levels exceed pipe elevations and a pipe is defective, then INFILTRATION
is the result.
IDM (INCH-DIAMETER-MILE)
A unit of ineasurement that takes into account a pipe's length and diameter.
Len.
IDM = Dia.x 5280
Since INFILTRATION is the result of groundwater surrounding the pipe, the diameter
component is very useful in summarizing infiltration results (i.e., GPD/idm).
INDEPENDENT SYSTEM
A SUB-BASIN that does not receive flow measured by any other flow monitors.
INFILTRATION
Groundwater entering a sanitary collection system through such means as, but not limited
to, defective pipes, pipe joints, connections or manhole walls.
INFILTRATION INCREASE
See INFILTRATION
INFLOW
Rain event RL1N-OFF which is discharged directly into a sanitary collection system from
such sources as, but not limited to, roof leaders, cellaz drains, foundation drains, manhole
covers, CROSS CONNECTIONS from storm sewers, and surface run-off.
UI
The combination of INFILTRATION and/or INFLOW.
ADS Environmental Services, Inc.
VI-3
INUNDATED
A general term indicating that water drains to and ponds over or floods a LEAK source.
This is to be distinguished from water moving over a source. Inundation normally results
in a severe leaking defect.
LEAK
A collection system DEFECT that is either observed to be actively contributing UI or
exhibits EVIDENCE that UI has occurred or will occur.
LINE SEGMENT
That portion of the MAINLINE between an upstream and downstream MANHOLE. In
order to note the location of a DEFECT or LEAK, a line segment consists of the
upstream manhole and the outgoing collection pipe up to, but not including the
downstream manhole.
LINE CLEANING
The process by which mud, sand and debris, or grease is removed from a collection line.
Although other methods are available, this is normaily accomplished by pulling a high
pressure water nozzle back through a pipe thus scrubbing the walls with water and also
moving debris back towards the water source for removal. Line cleaning is normally
conducted prior to TV INSPECTION.
MAINLINE
That portion of gravity collection system (exclusive of SERVICE line) maintained by the
system owner. This pipe is usually located in a right-of-way (or easement) that is
normally located between two MANHOLES but is occasionally a lateral segment with no
upstream manhole.
MAINTENANCE
The process by which sewers are cleazed of debris, grease or blockages. Maintenance is
primarily conducted in order to improve hydraulic efficiency.
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MANHOLE
A point of service entry where the collection line can be observed or maintained. An
upstream manhole receives sewage and through its outgoing line contributes flow
towards a downstream manhole.
MANHOLE INSPECTION
The process by which a variety of information concerning MANHOLES is obtained.
This information includes dimensions, construction materials, general conditions and
DEFECTS/LEAKS. Manhole inspections are either above ground in which observations
are made without descending the manhole or below ground in which the manhole is
either descended or observed by some type of viewing device. Below ground inspections
include information from that portion of each LINE SEGMENT that can be observed
from the manhole being inspected.
MIGRATION
Flow removed from one defect, in many cases, can "migrate" and enter the system
through another defect that has not been REHABILITATED. This can reduce the
accuracy of rehabilitation removal estimates.
MUNICIPAL SERVICE
A service line that directs flow from a residence or business to either a MAINLINE or
MANHOLE. Municipal service is that portion of the service line located within the
MAINLINE right-of-way (or easement). Generally, this is service line located between
the MAINLINE and the property line.
PRIVATE SERVICE
That portion of the service line located on private property.
QUANTIFICATION
The process by which flow RATES aze estimated for leaking DEFECTS. Leak rates are
assigned based upon observed EXTRANEOUS flow, EVIDENCE of I/I, the type of
defect and drainage potential.
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RAPID INF[LTRATION
A component of RAIN INDUCED UI. It can occur during and/or just after a RAIN
EVENT as a result of RLJN-OFF entering the pipe trench and entering the pipe through,
typically, infiltration defects but acting in the same manner as does INFLOW. In most
cases, without considerable investigation, it is not distinguishable from INFLOW.
REHABILITATION
The process by which LEAKS and DEFECTS are repaired thus reducing the amount of
UI entering a SANITARY COLLECTION SYSTEM.
RUN-OFF
That portion of storm water that remains primarily at the ground surface as opposed to
penetrating the soil.
SANITARY COLLECTION SYSTEM
MAINLINE, SERVICE LINES and MANHOLES maintained by a municipality, county,
or other agency.
SERVICE LINE
A service line directs flow from a resident or business to either a MAINLINE or
MANHOLE. Municipal service is that portion of the service line located within the
MAINLINE right-of-way (or easement). Private service line is located on private
property.
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SEWER SYSTEM EVALUATION SURVEY (SSES)
The process by which sources of INFILTRATION and INFLOW are located, quantified
and recommended for rehabilitation. An SSES Project typically consists of work phases
including:
• CONTINUOUS FLOW MONITORING
• MANHOLE INSPECTION
• SMOKE TESTING/DYE TESTING
• FLOW ISOLATION
• WET WEATHER INSPECTION
• CLEANING/TV 1NSPECTION
SMOKE TESTING
The process by which smoke (actually Zinc Chloride mist) is introduced into the system
under pressure. The method is best used to detect inflow sources such as roof leaders,
azea drains, foundation drains, abandoned building sewers, faulty connections, illegal
connections and storm drain connections. Smoke should exit the system at the point
where INFLOW can enter the system.
STRUCTURAL DEFECT
A defect that exhibits no EVIDENCE that it has or will LEAK.
SUB-BASIN
Large drainage areas are divided into smaller areas called SUB-BASINS that typically
consist of 6,000 to 20,000 linear feet. These areas aze isolated during flow monitoring in
order to determine what portions of the overall system should be further studied. If
INFILTRATION is determined to be a problem, then SUB-BASINS are normally further
divided into micrasystems consisting of between 1,000 to 6,000 LF. These smaller
systems are used for the purpose of conducting FLOW ISOLATION.
SWAG
A depression or dip in a sanitary collection line. Swags decrease hydraulic efficiency.
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TAP
The point where a service line connects to the MAINLINE. This is a frequent location
for a DEFECT. Cracks and breaks at this connection often result in LEAKS. At times
service lines protrude into the MAINLINE resulting in inefficient hydraulics. Service
taps are sometimes referred to as hammer taps when not properly connected or factory
taps when properly connected.
TROUGH/CHANNEL/INVERT
That portion of a manhole in which sewage flows. The depth of a manhole is measured
from the top of the CASTING to the bottom of the invert.
TRUNK LINE
That portion of the sanitary system that collects flow from smaller pipe, sometimes called
lateral line. This normally larger diameter pipe carries the flow to a treatment plant or
major pump station.
TV INSPECTION
The process by which a collection line is viewed with a closed circuit television camera
while pipe conditions are simultaneously observed on a TV monitor. Documentation is
made by video tapes or with photographs from the monitor. TV inspection normally
follows LINE CLEANING.
WET WEATHER INSPECTION
The process by which a sanitary collection system is observed during a storm event.
Manholes are opened to check the effects of inflow, areas are observed to confirm
ponding and inundation, and DYE TESTS are conducted.
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B. Rehabilitation Code Definitions
Manhole Rehabilitation Codes
01 - Install Inflow Dish at Manhole Cover
An inflow dish is a semi-hemispherical dish with a flat rim of the same diameter
as the manhole frame. When the cover is placed over the inflow dish, its weight
effects a seal between the inflow dish and frame, preventing inflow of water
through pick holes, vent holes, or a poorly seated cover.
02 - Install Manhole Cover Gasket
Some manhole frame and cover styles include a gasket which fits on top of the
manhole frame ledge which supports the cover or on the bottom of the cover.
This rehabilitation method addresses the replacement of the gasket.
03 - Pluiz Vent Holes in Manhole Cover
T'he simplest method for sealing vent holes in manhole covers subject to sheeting
or runoff is to use rubber inserts made specifically for this application. These
inserts are not a long term solution for manholes located in traffic azeas.
04 - Replace Manhole Cover
A missing or defective manhole cover creates both an inflow source and a safety
concern. This rehabilitation method addresses only the cover. In some older
installations, a new manhole cover and frame may be needed if the cover is of an
unusual style.
OS - Replace Missing Manhole Cover Bolts
This rehabilitation method addresses missing bolts in a bolted cover.
06 - Install Manhole Frame and Cover - Standard
A broken or damaged manhole frame can become an inflow source and a safety
hazard. This rehabilitation method addresses installation of a new frame and
cover on an existing manhole.
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07 - Install Manhole Frame and Cover - Raise Manhole to Grade
A broken or damaged manhole frame can become an inflow source and a safety
hazard. This rehabilitation method addresses installation of a new frame and
cover on an existing manhole located in an area subject to inundation or heavy
runof£ Additionally the manhole cover needs to be raised to grade as described
in rehabilitation code 08 below.
08 - Raise Manhole to Grade
Due to re-paving, settlement, and grade changes, a manhole may be covered or
become subject to inundation. The solution is to raise the manhole to the grade of
the surrounding area. In a paved area, this entails removing pavement to gain
access, excavation to expose the frame to chimney or frame to cone connection,
and removal of the frame. Then vertical spacers are inserted, waterproofed on the
exterior, and the frame is re-installed and sealed, followed by backfilling and
pavement replacement. In cases where the manhole is a foot or more below
grade, it may be necessary to add a chimney above the existing cone or to remove
the cone, construct an addition to the wall, re-install the cone, and follow the
steps detailed above.
09 - Realign and Seal Manhole Frame
Cementitious materials are normally used to seal a frame to the top of the
manhole cone or chimney. This seal can become damaged and, in severe cases,
the frame can be offset from the manhole. In a paved azea, rehabilitation entails
removing pavement to gain access, excavation to expose the frame to chimney or
frame to cone connection, and removal of the frame. The frame is realigned and
sealed, followed by backfilling and pavement replacement.
10 - Repair Leak at Manhole Lid Adjuster
Various types of adjusters may be used to raise or level a manhole frame. This
rehabilitation method addresses realignment and re-sealing around the defective
adjuster.
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11 - Seal Casting to Chimney
Cementitious materials are normally used to seal a frame to the top of the
manhole chimney. This seal can become damaged and allow inflow of water into
the manhole. Rehabilitation entails excavation to expose the frame to chimney
connection, and removal of the frame. The frame is re-sealed and backfilled,
followed by pavement replacement, if necessary.
12 - Seal Castiniz to Cone
Cementitious materials are normally used to seal a frame to the top of the
manhole cone, if no chimney is present. This seal can become damaged and
allow inflow of water into the manhole. Rehabilitarion entails excavation to
expose the frame to cone connection, and removal of the firame. The frame is re-
sealed and backfilled, followed by pavement replacement, if necessary.
13 - Plug and Waterproof Coat Manhole Chimnev
Various defects can develop in chimneys, permitting inflow through cracked or
missing mortar, holes, and defective or missing bricks. This rehabilitarion method
consists of cleaning the wa11s, repairing holes and cracks, and applying cement
based grout in multiple layers.
14 - Plug Lift Holes in Manhole Chimnev
The sealant material used to seal the precast lift holes has deteriorated or is
leaking. This rehabilitation method addresses removal of the deteriorated sealing
material and replacement with non-shrink grout or other sealant.
15 - Rebuild Manhole Chimney
The manhole chimney is deteriorated to the point where it is structurally unsound
and standard repair methods will not be effective. This rehabilitation method
addresses excavating to expose the manhole down to the chimney to cone joint,
installing a new chimney, re-seating the frame, backfilling, and pavement
replacement.
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16 - Repair Leaks Manhole Chimne J~nts
Manhole chimneys constructed of precast grade adjustment rings can develop
leaks between the rings. The rehabilitation method for these defects is to re-seal
with a non-shrink grout or other sealant.
17 - Repair Leaks Manhole Chimnev Wall
In lieu of the plastering techniques described in rehabilitation method 13, each
defect may be individually repaired through use of non-shrink or flexible sealing
products.
18 - Plug and Waterproof Coat Manhole Cone
Various defects can develop in cones, permitting inflow through cracked or
missing mortar, holes, and defective or missing bricks. This rehabilitation method
consists of cleaning the walls, repairing holes and cracks, and applying cement
based grout in multiple layers.
19 - Plug Lift Holes in Precast Manhole Cone
The sealant material used to seal the precast lift holes has deteriorated or is
leaking. This rehabilitation method addresses removal of the deteriorated sealing
material and replacement with non-shrink grout or other sealant.
20 - Rebuild Manhole Cone
The manhole cone is deteriorated to the point where it is structurally unsound and
standard repair methods will not be effective. This rehabilitation method
addresses excavating to expose the manhole down to the cone to wall joint,
installing a new cone and chimney, re-seating the frame, backfilling, and
pavement replacement.
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21 - Repair Leaks Manhole Cone Joints
The precast joint between the cone and wall has deteriorated or is leaking. This
rehabilitation method addresses removal of the deteriorated sealing material and
replacement with non-shrink grout or other sealant. This repair may also include
the use of chemical gel sealants injected through the wall to effect a seal from the
outside.
22 - Repair Leaks Manhole Cone Wall
In lieu of the plastering techniques described in rehabilitation method 18, each
defect may be individually repaired through use of non-shrink or flexible sealing
products.
23 - Form and Pour New Manhole Wall
The manhole wall has deteriorated to the extent that structural failure is
imminent, and replacement is desirable. There are instances, however, where
adverse physical or traffic conditions make replacement difficult. In such cases, a
solution can be to remove the frame, place a liner in the manhole, and pour
concrete in the annular space between the liner and the wall.
24 - Plug and Waterproof Coat Manhole Wall
Various defects can develop in walls, permitting inflow through cracked or
missing mortar, holes, and defective or missing bricks. This rehabilitation method
consists of cleaning the walls, repairing holes and cracks, and applying cement
based grout in multiple layers.
25 - Plug Lift Holes Precast Manhole Sections
The sealant material used to seal the precast lift holes has deteriorated or is
leaking. This rehabilitation method addresses removal of the deteriorated sealing
material and replacement with non-shrink grout or other sealant.
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26 - Repair Leaks Manhole Wall
In lieu of the plastering techniques described in rehabilitation method 24, each
defect may be individually repaired through use of non-shrink or flexible sealing
products.
27 - Seal Precast Manhole Joints
The precast joint between wall sections has deteriorated or is leaking. This
rehabilitation method addresses removal of the deteriorated sealing material and
replacement with non-shrink grout or other sealant. It may also include the use of
chemical gel sealants injected through the wall to effect a seal from the outside.
28 - Remove Manhole Steps and Seal Holes
If manhole steps aze sufficiently deteriorated to be unsafe, they should be
removed and not replaced. The holes left should be sealed with non-shrink grout
or other sealant.
29 - Replace Manhole Steps
Not used.
30 - Install New Manhole Bench and Channel
The bench has deteriorated, and in severe cases, is entirely broken or missing.
The solution is to break out the existing bench and rebuild it.
31 - Repair Leaks Manhole Bench
Defects exist on the bench but deterioration is insufficient to justify replacement.
This rehabilitation method addresses repair of leaks through the use of non-shrink
grout and/or other sealant materials.
32 - Rebuild Manhole Channel
The channel or invert of the manhole is severely broken or cracked. This
rehabilitation method addresses breaking out the existing channel and building a
new one.
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33 - Repair Leaks Manhole Channel
A solution to less severe defects in the manhole channel is to apply non-shrink
grout or other sealant to the individual defects.
34 - Remove Manhole Deposition - Medium
This rehabilitation method applies to manholes with one to three inches of debris
in the bottom.
35 - Remove Manhole Deposition - Heaw
This method is used for manholes with over three inches of debris on the bench
and channel.
36 - Locate Manhole - Raise to Grade
The manhole was unable to be located during field inspection activities. The
manhole must be located through the use of an internal TV camera or other
means, and raised to grade for inspection as detailed in Rehabilitation Code 08.
37 - Uncover Manhole - Raise to Crrade
The manhole was located during field inspection activities, but was buried and
could not be excavated. The manhole must be raised to grade for inspection as
detailed in Rehabilitation Code 08.
391 - Replace Manhole
This method is normally recommended only for manholes with multiple heavy
defects. However, it is also used for manholes in older systems with few defects
but signs of deterioration.
392 - Plug and Waterproof Coat Entire Manhole
Rather than plug and coat or patch individual sections of manholes, it may be
advantageous to coat the entire manhole, especially in older brick manholes
which are deteriorated. The method used involves cleaning the walls, patching
holes or cracks, and coating with a waterproofing sealant in multiple applications.
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393 - Replace Flush Tank w/ Standard Manhole
Flush tanks, which were previously used to clean lines with a large flush of water,
were another unusual condition encountered. It is recommended that all flush
tanks be replaced with a standard manhole.
394 - Replace EOL, Tee, or Cleanout w/ Standard Manhole
It is recommended that manholes be placed at all ends of lines and at all junctions
between two or more mainlines, to facilitate inspection and reduce maintenance
costs.
395 - Replace Oval Frame and Cover w/ Standard Frame and Cover
The oval-shaped manhole frame and cover found on some brick is sub-standard
and requires replacement. The rehab code addresses replacing the cover and
frame with a standard round cover and frame. In a paved area, rehabilitation
entails removing pavement to gain access and excavation to remove the frame.
The new frame is sealed to the corbel or chimney, followed by backfilling and
pavement replacement.
84 - Unidentified Smoke Leak - Dye Test Required
Manhole defects found during smoke testing are typically characterized as either
frame defects, frame seal defects, chimney defects, cone defects, or wall defects.
There are instances, however, where the manhole appears to be in good condition
from physical inspection. These defects should be dye tested to determine the
exact nature of the problem, and the cost for this rehab code includes only the
cost to dye test.
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Mainline Rehabilitation Codes
40 - Minor Defects- Clean, TV Inspect Line
Minor mainline defects should be watched and eventually repaired, but are not as
critical to the system condition as other, more severe defects. A code of 40,
including the cost for televising and cleaning only, was assigned if no roots were
found.
41 - Minor Defects - Remove Roots, Clean, TV Inspect Line -
Minor mainline defects should be watched and eventually repaired, but are not as
critical to the system condition as other, more severe defects. If roots were
encountered with a minor mainline defect, a code of 41, which includes cost for
televising and de-rooting, was assigned.
42 - Install Sleeve at Exposed Pipe
An exposed pipe in a ditch is permitting inflow. This rehabilitation method
addresses pouring a concrete collar around the pipe or otherwise sleeving the
portion of the pipe leaking.
43 - Mainline Point Repair
T'his repair consists of excavating, exposing, and repairing individual or multiple
defects located on 15 feet or less of mainline. T'he cost of such a repair varies
depending on depth, pipe diameter, surface cover, traffic conditions, and several
other factors.
431 - TV Inspect Line - Mainline Point Repair
Mainline point repair defects found through manhole inspection (lamping) were
recommended for televising before repair to avoid unnecessary rework due to
additional defects that might be found farther in the line. This rehab code
includes the cost of rehabilitation for the point repair(s) and the cost to televise
the line.
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432 - Remove Roots TV Inspect Line - Mainline Point Repair
Mainline point repair defects with roots found through manhole inspection
(lamping) were recommended for televising before repair to avoid unnecessary
rework due to additional defects that might be found farther in the line. This
rehab code includes the cost of rehabilitation for the point repair(s), cost to de-
root the line, and the cost to televise the line.
44 - Partial Mainline Replacement
This repair consists of excavating, exposing, and repairing multiple defects
located on 15 feet or more of mainline. The cost of such a repair varies
depending on length, depth, pipe diameter, surface cover, traffic conditions, and
several other factors.
441 - TV Inspect Line - Partial Mainline Replacement
Mainline defects requiring partial replacement found through manhole inspection
(lamping) were recommended for televising before repair to avoid unnecessary
rework due to additional defects that might be found farther in the line. This
rehab code includes the cost of rehabilitation for the point repair(s) and the cost to
televise the line.
442 - Remove Roots, TV Inspect Line- Partial Mainline Replacement
Mainline defects requiring partial replacement found through manhole inspection
(lamping) were recommended for televising before repair to avoid unnecessary
rework due to additional defects that might be found farther in the line. This
rehab code includes the cost of rehabilitation for the point repair(s) and the cost to
de-root and televise the line.
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45 - Repair Faulty Mainline Tap
Normally, the only way to identify a faulty mainline service tap is through
television inspection. The exception occurs when the defect is visible from the
manhole during physical inspection. The leak can occur in two ways: an installed
wye can be defective or a hammer tap exists. A hammer tap occurs when a
service line is attached to the mainline by simply knocking a hole in the line,
inserting the pipe, and sealing azound the opening with ceinent or another sealant.
This rehabilitation method consists of excavating to expose the service line,
installing a new wye, and reconnecting the service line. An alternative method
for a structurally sound service connection is to seal the tap with chemical grout.
46 - Repair Manhole/Pipe Connection - External
Defects often develop at the connection between the collection main and the
manhole wall. If the defect cannot be repaired from within the manhole,
excavation to expose the defect and repair from outside by sleeving or patching is
required. Normally, any connection defect which extends into the pipe will
require an external repair because at least one joint of pipe will need to be
replaced.
47 - Repair Manhole/Pipe Connection - Internal
The seal at the pipe connection leaks or has minor root intrusion. This
rehabilitation method addresses patching from the inside of the manhole using a
non-shrink grout or chemical grout injection.
48 - Pluiz Storm Drain at Main - Direct Connection
The simplest way to repair an illegal direct connection is to plug the storm drain
where it connects to the sanitary line. Additional costs will accrue if the storm
drain must have new connections to the remainder of the drainage systems.
These costs are not accounted for in the cost tables.
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49 - Repair Storm/Mainline Cross-Connection
An indirect cross connection between the sanitary and storm system allows
rainfall to enter the system by way of the cross connection. If the sanitary line
passes through the storm line, there is also a potential for exfiltration of
wastewater into the storm drainage system. Without extensive investigation of
both the sanitary and the storm systems, it is difficult to determine the optimal
repair method. Typically, however, the repair will involve repairing both the
sanitary and storm sewers contributing to the defect. Therefore, this defect type
is assigned a high cost to allow leeway in repair methods.
491 - Investigate Suspect Storm/Main Connection
This rehab code includes the cost to dye, televise, and point repair the defect.
Depending on the severity of the problem as determined through television
inspection, additional rehabilitation for the entire line segment may be necessary,
and this cost is not included.
50 - P1uQ Abandoned Mainline at Manhole
An abandoned collection line is found connected to a manhole. This
rehabilitation method addresses plugging the line to eliminate possible I/I and
debris from entering the system.
51 - Plug Overflow at Exit from Manhole
A constructed overflow pipe is found connected to a manhole. This rehabilitation
method addresses plugging the line.
52 - Plug Storm Connection at Manhole
The recommended repair for a storm line connected directly to a manhole is to
plug it. Additional costs may result, however, if additional storm system
connections have to be built to carry runoff.
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53 - Plug Stub at Manhole
A constructed plug at a manhole leaks or is deteriorated. This rehabilitation
method addresses plugging the line to eliminate possible I/I.
54 - Line Cleaning - Medium Deposition
This rehabilitation method indicates up to 20% of pipe depth contains debris and
should be cleaned.
55 - Line Cleaning - Heaw Deposition
T'his rehabilitation method indicates more than 20% of pipe depth contains debris
or that debris is hard-packed and should be cleaned.
56 - Remove Mainline Blockage
This rehabilitation method indicates a blockage exists in the line and should be
removed.
57 - Flapgates, Project Engineer to Determine
This rehabilitation code is a special code for end-of-line manholes with flapgates
installed in the outgoing line. This rehab is left to the Project Engineer to
determine the course of action, hence no cost or UI removal is associated.
691 - Clean, Televise, and Repair Mainline
This lump sum cost is used as a broad generalization when defects are known to
exist and includes the cost of cleaning, televising, and sealing leaks with chemical
grout injection, as described in rehabilitation method 40.
692 - Construct Manhole, Test, and Grout Mainline
This rehabilitation method is similaz to 40, but with the added cost of
constructing a new manhole on segments which have no upstream access
structure.
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693 - Install Cured-in-Place Liner
A cured-in-place liner can be a long-term, cost effective rehabilitation alternative
to pipe replacement, especially for deep pipes and pipes under busy thoroughfares
or railroad tracks. However, collapses, severe offsets, and any other restrictions
must be repaired before the liner is installed. Typical cured liners are installed by
inflating with heated water under pressure until the liner is cured, and then re-
establishing the service connections. Typically, installation will require bypass
pumping to maintain system flows and avoid backup in upstream lines. This cost
is not included in the cost tables.
694 - Install Formed-in-Place Liner
This rehabilitation method is similaz to method 693 except the liner is at least
partially cured and requires only heat and pressure to reform it within the line.
695 - Slipline Entire Mainline Segment
Sliplining may consist of either inserting smaller diameter pipe into an existing
pipe if capacity is not a concern, or of pipe bursting followed by insertion of
similar or slightly larger size pipe. This rehabilitation method addresses only
inserting smaller diameter pipe into existing pipe. Any severe restrictions must
be repaired before sliplining is done. An access pit is constructed, usually at one
end of the segment, or at the location of a point repair to be made, if such exists.
696 - Replace Entire Mainline
T'his method is recommended if the structural integrity of the pipe is
compromised, or if point repairs to prepare a pipe for lining aze prohibitively
expensive. In unpaved areas, it is usually the most cost effective way to repair a
line with multiple defects.
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Service Line Rehabilitation Codes
70 - Disconnect Roof Drains
Roof drains that are found to be connected to the sanitary system should be
disconnected and re-routed to the storm drainage system.
71 - Disconnect Yazd Drain from Service Line
Like roof drains, yazd drain and basement drain connections to the sanitary
system are illegal and should be disconnected.
72 - Plug Abandoned Service at Propertv Line
Typically found where old houses have been torn down and where mobile homes
have been removed, abandoned service lines can become inflow sources. The
appropriate repair is to plug the service line at the property line.
73 - Service Line Point Repair
This lump sum repair covers rehabilitation of service line defects which require
excavation and replacement of a section of pipe less than 15 feet.
74 - Service Line Clean - Remove Deposition
This rehabilitation method is for cleaning or removing any debris or blockage in a
service line.
75 - Point Repair Storm/Service Cross Connection
This repair accounts only for the cost of repairing the service line to prevent
inflow from entering the system. It does not account for any repair to the storm
line.
751 - Investi atg e Suspect Storm/Ser✓ice Connection
This rehab code includes a normal rehabilitation cost, dye test cost, and cost to
televise the line to which the service connection is tributary.
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76 - ReQair Exposed Service at Ditch Line
An exposed pipe in a ditch is permitting inflow. This rehabilitation method
addresses pouring a concrete collar around the pipe or otherwise sleeving the
portion of the pipe leaking.
77 - Repair Poorly Disconnected Roof Drain
This repair addresses drains disconnected from the collection system which have
not had their runoff re-routed sufficiently away from the plugged service line
connection.
78 - Repair, Replace, Install Cleanout
A cleanout structure on a private service line is damaged, and is a source of
inflow to the system. The typical rehabilitation method is replacement of a
damaged cleanout, repair of one with minor damage, and installation where one is
required.
781 - Replace End-of-Line Seg!nent or Cleanout With New Cleanout
This rehabilitation is recommended for all defective cleanouts on lines that aze 6
inches in diameter or less and all end-of-line segments on lines that aze 6 inches or
less in diameter.
79 - Replace Section of Service Line
T'his repair applies to service line defects which require replacement of more than
15 feet. It is still a lump sum cost, however, and may be low for very long
service lines that need replacement.
80 - Replace Cleanout Cap/Cover
This repair is recommended where a cleanout structure is missing its cover but is
in otherwise good condition.
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Clean and TV Inspection
85 - Clean, TV Inspect Line
This method is based on use of nothing more than a standard jet cleaner truck.
86 - Heavy Clean, TV Inspect Line
T'his method is used when debris is more than 20% of pipe depth and typically
includes use of power rodders, bucket machines, or proloriged use of a jet cleaner.
87 - Remove Roots, Clean. TV Inspect Line
This rehabilitation method is applicable when it is necessary to remove roots from
the line prior to TV inspection. Typically, these roots are no larger than an inch
and can be removed by various cutting devices. An example is a hydrostatically
driven unit with circular blades powered by the water pressure in a jet cleaner
truck.
88 - Remove Heavy Roots, Clean, TV Inspect Line
This rehabilitation method is similaz to rehabilitation method 87 except the
degree of root intrusion is greater and requires more time and heavier equipment
to remove the roots.
ADS Environmental Services, Inc.
VI-25
Maintenance Rehabilitation Codes
91 - Remove Flush Valve from Manhole
Older systems sometimes had a water line and valve installed in selected
manholes located on lines with low flows. By turning on the water, additional
flow was created to flush the line. These old installations should be removed.
92 - Other Utilities Pass throu Manhole
In older systems, it is not uncommon to find other utilities passing through a
manhole. These lines can pose a safety hazard to workers entering the manhole,
become UI sources, and create dangerous conditions for the public if the utilities
include water or gas conduits.
ADS Environmental Services, Inc.
VI-26