HomeMy WebLinkAboutItem 5c. Whale Rock Dam Pipeline Replacement StudyCity of San Luis Obispo, Title, Subtitle
Whale Rock Commission Report
Whale Rock Commission Meeting – May 8, 2025
Agenda Item 5 – Alternative Pipeline Replacement Study
FROM: Aaron Floyd, Utilities Director
PREPARED BY: Noah Evans, Whale Rock Supervisor
SUBJECT: Whale Rock Dam, Pipeline Replacement Study
RECOMMENDATIONS
No action is requested by the commission for this agenda item.
DISCUSSION
Background
As previously authorized during the 2023
Whale Rock Commission meeting, the
Pipeline Replacement Study was initiated to
explore various options for renewing the
Whale Rock pipeline, which has been in
service for over six decades. The Study
provides a roadmap for maintaining the
integrity of the Whale Rock water delivery
system by providing pipeline renewal and
replacement recommendations. The study is
nearly complete, and staff wish to update the
Commissioners on its contents.
As part of this project, HDR Engineering was tasked with reviewing the condition of
the existing pipeline from the 2019 Pipeline Inspection Report and recommending
suitable replacement strategies. The study provides pipeline replacement options,
cost analysis, and an implementation timeline. Understanding the cost of pipeline
renewal will allow Commission members to prepare for increases in future Whale
Rock CIP contributions, which will ultimately be required to keep the pipeline in proper
working order.
Pipeline Replacement Study Recommendations
The recommendations from the Pipeline Replacement Study are multi-phased and
are as follows:
1. Execute Alternative 3: This involves replacing the defective sections of
pipeline in the area of the golf course (223 feet), as was previously approved
by the commission. In addition, HDR recommends replacing one additional
section of piping to the east of the golf course.
2. Reinspect the Pipeline: After completing the initial repairs, it is recommended
that staff conduct a thorough reinspection of the pipeline to assess its condition
WHALE ROCK PIPELINE REPAIR
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Whale Rock Commission Meeting – May 8, 2025
Agenda Item 5 – Alternative Pipeline Replacement Study
and identify any further necessary actions. This inspection is shown within the
Whale Rock CIP schedule to occur in 2028.
3. Implement Alternative 6: Following the reinspection, proceed with a 100%
pipeline replacement over a specified period. This ensures that all
compromised sections are effectively addressed.
The study examined different methods for pipeline replacement. These methods
included full replacement with a new line, using the existing line as a sleeve for a
smaller diameter line, and adding an internal liner to the existing pipe. The
recommendation from HDR is to replace the entirety of the pipeline with a new line.
Staff will return to the Whale Rock Commission at a future meeting with more
information regarding how the timeline in which the pipeline would be replaced
(replacing all of the pipeline at once versus replacing smaller sections annually until
full replacement is completed) .
Engineering estimates for full scale pipeline replacement and associated costs can
be seen in Table 1 below. Staff have not identified which replacement timeline is most
efficient for pipeline replacement at this time but will coordinate with staff from
member agencies to develop a schedule for replacement that minimizes impacts to
each participating agency.
Table 1 – Whale Rock Pipeline Replacement Timeline Options
Option Replacement
(MI/YR)
Replacement
(%/YR)
# of YR for
100%
Replacement
Construction
OPCC ($/YR)
Project
OPCC
($/YR)
1 0.46 2.86 35.0 $1.99M $2.85M
2 0.53 3.33 30.0 $2.33M $3.33M
3 0.64 4.00 25.0 $2.79M $3.99M
4 0.80 5.00 20.0 $3.49M $5.00M
5 0.93 5.81 17.2 $4.06M $5.80M
6 1.07 6.67 15.0 $4.65M $6.65M
7 1.33 8.33 12.0 $5.82M $8.31M
8 1.60 10.00 10.0 $6.98M $9.98M
9 3.20 20.00 5.0 $13.95M $19.95M
10 16 100.00 1.0 $69.77M $99.77M
ENVIRONMENTAL REVIEW
No environmental review is required to update the Commissioners on this study’s
progress.
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City of San Luis Obispo, Title, Subtitle
Whale Rock Commission Report
Whale Rock Commission Meeting – May 8, 2025
Agenda Item 5 – Alternative Pipeline Replacement Study
FISCAL IMPACT
Staff is not requesting that the Commissioners consider funding pipeline renewal at
this time. Cost estimates within this staff report should be as a rough estimate of
financial commitments that commission members may be requested to make as part
of a full-scale pipeline replacement project.
ALTERNATIVES
The Commission may direct staff to further study pipeline rehabilitation options or
cease pipeline rehabilitation and not bring future pipeline renewal projects to the
Commission for consideration. These alternatives are not recommended as staff
have determined that the pipeline study is accurate, and the Whale Rock pipeline
will become less reliable over time.
Attachments:
A - Whale Rock Dam Pipeline Replacement Study
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Alternative Analysis Report
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Contents
1 Purpose ............................................................................................................................................... 1
2 Background ......................................................................................................................................... 1
3 Design Considerations ........................................................................................................................ 6
3.1 Geotechnical ............................................................................................................................. 6
3.2 Mechanical ................................................................................................................................ 6
3.2.1 Replacement Pipeline Material .................................................................................... 6
3.2.2 Rehabilitation Pipeline Material .................................................................................... 6
3.2.3 Pipe Pressure ............................................................................................................... 7
3.2.4 Appurtenances ............................................................................................................. 7
3.2.5 Methodology ................................................................................................................. 7
3.2.6 Opinion of Probable Construction Cost (OPCC) .......................................................... 8
4 Alternatives .......................................................................................................................................... 9
4.1 Alt 1: Do Nothing ....................................................................................................................... 9
4.2 Alt 2: Golf Course Pipeline Project .......................................................................................... 10
4.3 Alt 3: Replace All Broken Bar Wraps & Localized Cylinder Wall Loss .................................... 12
4.4 Alt 4: Alt 3 + Broken Bar Wrap ................................................................................................ 12
4.5 Alt 5: Alt 4 + Localized Cylinder Wall Loss .............................................................................. 13
4.6 Alt 6: 100% Pipeline Replacement .......................................................................................... 13
4.7 Discussion ............................................................................................................................... 14
4.8 Summary ................................................................................................................................. 14
5 Recommendation .............................................................................................................................. 15
6 References ........................................................................................................................................ 15
Figures
Figure 1. Pure Technologies pipeline inspection limits ................................................................................ 1
Figure 2. Pipeline as-built drawing overlaid onto Google Earth to approximate pipeline alignment............ 8
Figure 3. Approximate pipeline alignment and appurtenance location recreated in Google Earth ............. 8
Figure 4. Relationship between historical break count and future performance ........................................ 10
Figure 5. Golf course pipeline project ........................................................................................................ 11
Figure 6. Sample sketch of pipeline replacement section with broken pipeline identified with red
“X”. The intermediate and end pipeline sticks will be replaced in addition to the broken
pipelines. ........................................................................................................................................ 11
Figure 7. Pipeline installed in paved road schematic ................................................................................A-3
Figure 8. Pipeline installed in unpaved road schematic ............................................................................A-4
Figure 9. Whale Rock Pipeline MS Excel hydraulic analysis spreadsheet for analyzing hydraulic
performance with potential reduced pipeline inside diameters .....................................................B-1
Figure 10. Pipeline alignment and elevations from Google Earth ............................................................B-2
Figure 11. Whale Rock Pipeline hydraulic analysis results in graphical format. 30-IN ID blue line
represents original pipeline. 25-IN ID with 30-IN OD red line represents 100% length
structural CIPP rehabilitation. 20-IN ID with 24-IN OD green line represents 100% length
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structural HDPE pipeline slip lining. 15-IN ID with 20-IN OD yellow line represents 100%
length structural HDPE pipeline slip lining. ...................................................................................B-3
Tables
Table 1. Summary of pipeline materials, lengths, and lengths between stops ............................................. 2
Table 2. Summary of pipeline defects ........................................................................................................... 3
Table 3. AWWA C-303 BWP broken bar wrap, quantity 10 .......................................................................... 4
Table 4. Localized cylinder wall loss, quantity 15 ......................................................................................... 4
Table 5. AWWA C-303 BWP broken bar wrap and localized cylinder wall loss, quantity 5 ......................... 4
Table 6. Localized Anomalies Different than Broken Bar Wraps and Cylinder Wall Loss, quantity 6 .......... 5
Table 7. Less certainty, quantity 22 .............................................................................................................. 5
Table 8. Pipeline material EULs ................................................................................................................... 9
Table 9. Pure Technologies identified broken bar wrap and localized cylinder wall loss at golf
course............................................................................................................................................. 11
Table 10. Pipeline replacement priority ...................................................................................................... 12
Table 11. Pure Technologies identified broken bar wrap and localized cylinder wall loss for
Alternative 3 ................................................................................................................................... 12
Table 12. 100% pipeline replacement as a function of total replacement years ........................................ 13
Table 13. Pipeline replacement alternatives summary ............................................................................... 14
Table 14. Pipeline installed in paved road per linear foot .........................................................................A-3
Table 15. Pipeline installed in unpaved road per linear foot .....................................................................A-4
Table 16. Alternative OPCC summary ......................................................................................................A-5
Table 17. Alt 2: Golf Course Pipeline Project OPCC .................................................................................A-6
Table 18. Alt 3: Replace All Broken Bar Wraps and Localized Cylinder Wall Loss OPCC .......................A-7
Table 19. Alt 4: Alt 3 + Broken Bar Wrap OPCC .......................................................................................A-8
Table 20. Alt 5: Alt 4 + Localized Cylinder Wall Loss OPCC .....................................................................A-9
Table 21. Alt 6A: 100% Pipeline Replacement minus Alt 3 OPCC ..........................................................A-10
Table 22. Alt 6B 100% Pipeline Replacement OPCC ..............................................................................A-11
Table 23. 30-IN diameter pipeline reduced flow rates, velocities, and TDHs ............................................B-5
Table 24. HDPE IPS Pressure Pipe DR and diameters for slip lining .......................................................B-5
Appendices
Appendix A. OPCC ........................................................................................................................A-1
Appendix B. Hydraulics Analysis ...................................................................................................B-1
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1 Purpose
The purpose of the alternative analysis report (report) is to describe potential projects to replace
and/or rehabilitate the aging Whale Rock Dam Pipeline (pipeline) infrastructure. Six (6) alternates
are provided with their opinion of probable construction costs (OPCC), and timeline (immediate,
intermediate, and/or extended).
2 Background
The 30 IN pipeline was installed in 1959, 65 years old, and conveys raw water from Whale Rock
Reservoir to the San Luis Obispo Treatment Plant for a total distance of approximately 16 miles
northeast of San Luis Obispo, California, Figure 1. The pipeline is owned by the Whale Rock
Commission (Commission), consisting of the California Polytechnic State University (Cal Poly),
California Men’s Colony, and the City of San Luis Obispo (City).
Figure 1. Pure Technologies pipeline inspection limits
The pipeline is comprised of two pipeline materials:
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· AWWA M11 welded steel pipeline (WSP) at approximately 18,321 FT or 21.9% of total
length; and
· AWWA C-303 bar wrapped concrete cylinder pipeline (BWP) at approximately 65,523 FT or
78.1% of total length
Due to the pipeline age, the City procured Pure Technologies, a Xylem brand, in October 2018 to
conduct pipeline non-destructive interior testing with 99.0% tested, Table 1. Pure Technologies’
free-swimming electromagnetic inspection platform robot inspected, located, and identified pipe
sections with broken bar wraps, localized cylinder wall loss, broken bar wraps and localized cylinder
wall loss, and other anomalies not aforementioned.
Table 1. Summary of pipeline materials, lengths, and lengths between stops
Section Pipe Material Start Station End Station Distance (Mile)
A BWP, 30-IN 0+01 96+30 1.83
Pump Station Unknown 96+30 116+96 0.39
B Steel, 30-IN 116+96 227+00 2.34
BWP, 30-IN 227+00 295+05 1.29
Steel, 30-IN 295+05 313+00 0.34
BWP, 30-IN 313+00 387+46 1.42
Steel, 30-IN 387+46 402+05 0.28
BWP, 30-IN 402+05 559+30 2.98
Steel, 30-IN 559+30 579+00 0.38
BWP, 30-IN 579+00 602+85 0.45
Pump Station Unknown 602+85 605+00 0.04
C BWP, 30-IN 605+00 843+72 4.51
Total Distance 15.82 (inspected)
16.25 (total length)
Note(s):
1. The piping portions of the pump stations were not inspected.
From Pure Technologies’ Pipeline Condition Assessment Report Appendix B, Pure Technologies’
inspection platform accuracy decreases and uncertainties increase with the following occurrences:
· Change in pipeline; and
· Electromagnetic data noise
Additionally, Pure Technologies results did not quantify the following:
· Wall loss depths; and
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· Quantity of broken bar wrap per pipeline stick
Lastly,
· In 2021, City replaced approximately 60-FT of pipeline near STA 368+35 due to corroded
cylinder wall failure. This defect was not detected by Pure Technologies in 2018;
· In 2023, City replaced approximately 17-FT of pipeline at STA 583+64 due to failed bar-
wrapping. This defect was detected by Pure Technologies in 1998; and
· Pure Technologies inspection is six years old and out of date. Pure Technologies
recommends an inspection frequency of every five years
Table 2. Summary of pipeline defects
Number of Pipe Include
Uncertainties Include
Uncertainties
Inspected 100% 83,844 FT
w/ Broken Bar Wraps 0.19% 160 FT
w/ Localized Cylinder Wall Loss 0.57% 481 FT
w/ Broken Bar Wraps and Localized
Cylinder Wall Loss 0.19% 160 FT
w/ Localized Anomalies Different than
Broken Bar Wraps and Cylinder Wall
Loss
0.36% 301 FT
w/ less certainty due to flow changes 0.80% 671 FT
Pump station sections (no data) 2.72% 2,281 FT
Number of Total Defects
(excluding PS sections) 2.11% 1,773 FT
Adjusted for uncertainties and uninspected in Table 2, the total pipeline uncertainty is approximately
1,773 FT or 2.11% of the pipeline. However, because of the undetected STA 368+35 pipeline
failure, the actual uncertainty might be higher than 2.11%. Therefore, HDR has the following
disclaimers:
1. HDR’s analysis is based on Pure Technologies October 2018 inspection and assumes the
following:
a. 2018 data as-is is accurate in 2024
b. The pipeline has not experience additional deteriorations since October 2019
2. Pipeline hydraulic transient, water hammering, pressure fluctuations, surge pressures,
thrusts, etc. are not issues;
3. Seismic events / earthquake ground shaking resulting in pipeline failures are not issues;
4. No bypass or backup will be required during pipeline replacement and/or rehabilitation; and
5. No environmental or culturally sensitive areas in the pipeline alignment for pipeline
replacement and/or rehabilitation due to previous ground disturbance
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The pipeline defects from Table 2 are further summarized in Table 3 to Table 7.
Table 3. AWWA C-303 BWP broken bar wrap, quantity 10
Ref # Piece
#
Start
STA
Stop
STA PL L (FT) PL Mat Reported
Class
Break Positional
Range (FT from
Start STA)
36 93 11+04 11+36 32 BWP 230 15.0-18.0
2511 1056 583+64 583+96 32 BWP 320 5.5-8.5
3262 737 686+59 686+90 32 BWP 340 6.5-8.5
3263 736 686+90 687+22 32 BWP 320 2.5-6.0
3264 735 687+22 687+54 32 BWP 340 2.5-5.5; 11.5-14.5
3266 733 687+86 688+18 32 BWP 340 3.5-5.5
3496 504 759+63 759+95 32 BWP 230 2.0-4.0
3545 455 774+58 774+89 32 BWP 230 2.5-4.0
3649 350 806+79 807+11 32 BWP 230 22.0-25.0
3662 337 810+93 811+25 32 BWP 230 22.5-27.0
Table 4. Localized cylinder wall loss, quantity 15
Ref # Piece
#
Start
STA
Stop
STA PL L (FT) PL Mat Reported
Class
279 2044 87+71 88+03 32 BWP 230-B
1085 N/A 145+87 146+23 36 STEEL N/A
1087 N/A 146+58 146+94 36 STEEL N/A
1189 N/A 176+82 177+17 36 STEEL N/A
1414 160 237+00 237+32 32 BWP 380
1501 1959 264+53 264+85 32 BWP 400
1508 1952 266+77 267+09 32 BWP 400
1532 1928 274+44 274+76 32 BWP 380
1775 1736 351+91 352+08 17 BWP 230
2480 N/A 573+31 573+66 36 STEEL N/A
3061 936 622+91 623+23 32 BWP 460
3066 932 624+18 624+50 32 BWP 480
3067 931 624+50 624+82 32 BWP 480
3068 930 624+82 625+14 32 BWP 480
3260 739 685+95 686+27 32 BWP 340
Table 5. AWWA C-303 BWP broken bar wrap and localized cylinder wall loss, quantity 5
Ref # Piece
#
Start
STA
Stop
STA PL L (FT) PL Mat Reported
Class
3262 737 686+59 686+90 32 BWP 340
3263 736 686+90 687+22 32 BWP 320
3264 735 687+22 687+54 32 BWP 340
3266 733 687+86 688+18 32 BWP 340
3496 504 759+63 759+95 32 BWP 230
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Table 6. Localized Anomalies Different than Broken Bar Wraps and Cylinder Wall Loss, quantity 6
Ref # Piece
#
Start
STA
Stop
STA PL L (FT) PL Mat Reported
Class
194 2128 60+70 61+02 32 BWP 230-B
241 2082 75+71 76+03 32 BWP 230-B
3034 963 615+40 615+72 32 BWP 400
3437 563 741+59 741+91 32 BWP 240
3464 N/A 749+88 750+29 41 STEEL N/A
3523 477 767+89 768+21 32 BWP 300
Table 7. Less certainty, quantity 22
Ref # Piece
#
Start
STA
Stop
STA PL L (FT) PL Mat Reported
Class
3397 603 728+89 729+21 32 BWP 230
3398 602 729+21 729+53 32 BWP 230
3541 459 773+31 773+62 32 BWP 230
3542 458 773+62 773+94 32 BWP 230
3543 457 773+94 774+26 32 BWP 230
3715 284 826+50 826+82 32 BWP 230
3716 283 826+82 827+14 32 BWP 230
3738 261 833+86 834+17 32 BWP 230
3739 260 834+17 834+49 32 BWP 230
3740 259 834+49 834+81 32 BWP 230
3741 258 834+81 835+13 32 BWP 230
3742 257 835+13 835+45 32 BWP 230
3743 256 835+45 835+77 32 BWP 230
3744 255 835+77 836+09 32 BWP 230
3745 254 836+09 836+41 32 BWP 230
3746 253 836+41 836+73 32 BWP 230
3747 252 836+73 837+05 32 BWP 230
3748 251 837+05 837+37 32 BWP 230
3749 250 837+37 837+44 9 BWP 230
3750 249 837+44 837+67 32 BWP 230
3751 248 837+67 837+89 23 BWP 500
3752 247 837+89 838+21 32 BWP 500
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3 Design Considerations
3.1 Geotechnical
No geotechnical data was provided to support the pipeline alternative analysis. The assumption will
be to rehabilitate or replace the pipeline existing alignment potentially reducing the need for
geotechnical data. For pipeline replacement, bedding and pipeline embedment material will be
imported, and excavated soil will be used for trench backfill. To minimize environmental impacts, the
trenches will be excavated vertically with the use of trench boxes. For rehabilitation, the launch and
receiving pits be shored with sheet piles, which will be specified by the designers and designed by
the contractor’s shoring sub. The pipeline is installed in paved and unpaved areas and the condition
of the surface will be replaced to its original condition.
3.2 Mechanical
3.2.1 Replacement Pipeline Material
Based on discussions with the City, BWP is not a preferred material for the new pipeline segments
based on maintenance and replacement issues. The following materials are potential replacement
alternatives:
· WSP with cement mortar lining and coating. Cement mortar will be applied in the field at all
joints on the interior and exterior of the pipe;
· Plastic without additional cathodic protection. Use of plastic pipe would potentially cause
discontinuities in the existing cathodic protection system requiring bridging of the currents;
and
· Ductile iron pipeline (DIP) with cement mortar lining and coating. DIP has better corrosion
protection and material costs but heavier than WSP. Additionally, DIP has an intrinsic +100
pound per square inch (PSI) surge protection over its pressure class
The new pipeline material internal diameter should be equal or greater than the existing 30-IN
diameter. A 30-IN nominal diameter plastic pipeline will have an inside diameter smaller than 30-IN
potentially effecting hydraulic performances negatively. WSP is more costly than DIP for similar
performance. Therefore, DIP was selected as the alternative analysis pipeline replacement material.
However, the other replacement materials can be selected during design.
3.2.2 Rehabilitation Pipeline Material
Pipeline rehabilitation requires the original pipeline as the host. Rehabilitation can either be liner or
structural type. Rehabilitation requires bonding to the host pipeline. Rehabilitation liner is thinner
requiring the host pipeline to be structurally sound. A structural rehabilitation is thicker, becomes the
structural member, and utilized when the host pipeline is corroded, cracked, broken, and/or
otherwise structurally compromised with the host pipeline acting as the conduit to install the
structural liner. The following materials are potential rehabilitation alternatives for non-structural
liners and full structural rehabilitation:
· Cured-in-place pipe (CIPP) for structural and non-structural rehabilitation
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· Slip-lining for structural and non-structural rehabilitation
· Close-fit lining / die-draw lining / roll-down lining / fold-and-form lining for non-structural
rehabilitation
· Spiral wound lining for non-structural rehabilitation
· Centrifugal cast concrete pipe lining (CCCPL) for non-structural rehabilitation
· Geopolymer lining for non-structural rehabilitation
· Manufactured-in-place composite pipe (MICP) for non-structural rehabilitation
CIPP liner rehabilitations might reduce inside diameters by 2 to 3-IN to 27 to 28-IN inside diameter.
Whereas, CIPP structural rehabilitations might reduce inside diameters by 4 to 5-IN to 25 to 26-IN
inside diameter. For this alternative analysis, CIPP is assumed as the choice for rehabilitation.
Approximately 30-IN outside diameter (OD) CIPP installation span is limited to approximately 400-FT
or less between launching and receiving pits and limited to 1-90 degree elbow bend or 2-45 degree
elbow bends. However, other rehabilitation alternatives can be selected during design.
For slip lining rehabilitation, a smaller diameter carrier pipeline is inserted into the existing larger 30-
IN diameter casing pipeline with the annual space between the carrier and casing pipelines filled
with grout or controlled low-strength material (CLSM). The slip lining carrier pipeline can be either a
lining if the casing pipeline is structurally sound or structural if the casing pipeline is not structurally
sound. Slip lining cannot accommodate elbow bends and will require launching pits at every elbow
bend. Depending on the slip lining pipeline diameter, launching pits might be required at the casing
pipeline joint deflections.
3.2.3 Pipe Pressure
Minimum pipe pressure should meet or exceed the existing pipeline pressure class that ranges from
230 to 500 PSI. WSP and DIP can meet or exceed the required pressures, whereas, plastic pipeline
and rehabilitation (liner and structural) might not meet the higher required pressures.
Because plastic pipeline and rehabilitation (liner and structural) reduce pipeline inside diameter,
reduce hydraulic performance, and do not meet higher pressures, they have limited applications and
will not be recommended for the alternative analysis.
Refer to the appendix for additional pressure and hydraulic discussions.
3.2.4 Appurtenances
The pipeline appurtenances including but not limited to isolation valves, air release valves (ARVs),
combination ARVs, blowoffs (BOs), and cathodic test stations will be replaced as required with the
pipeline.
3.2.5 Methodology
The provided background data was reviewed the pipeline as-built drawing overlaid onto Google
Earth to determine the approximate pipeline alignment and appurtenance location, Figure 2 and
Figure 3, respectively.
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Figure 2. Pipeline as-built drawing overlaid onto Google Earth to approximate pipeline alignment
Figure 3. Approximate pipeline alignment and appurtenance location recreated in Google Earth
The as-built drawing data was inserted into worksheet, compared with Pure Technologies data, and
analyzed. All pipeline rehabilitation and replacement materials and installation methods were
analyzed with the following criteria for evaluating rehabilitation or replacement methods:
· To maintain or improve performance (hydraulics, corrosion resistance, etc.);
· To extend pipeline estimated useful life (EUL) / remaining useful life (RUL);
· To prevent unnecessary pipeline breaks;
· To identify most cost-effective methods to rehabilitate or replace including accessibility; and
· To increase confidence in decision making
3.2.6 Opinion of Probable Construction Cost (OPCC)
An AACE Class 5 estimate (-50% to +100% accuracy range) was developed for the pipeline
alternatives. Quantities were prepared based on the anticipated construction method and sequence.
Costs were applied based on AACE methodology for the Class 5 estimate level. The detailed
breakdown of costs is included in Appendix A.
Additional soft costs are included in Appendix A to provide additional indirect costs that may be
anticipated, including:
· Estimate and design contingency reflective of design
· Market volatility contingency due to supply chain issues, labor shortages, fuel prices, COVID,
inflation
· Construction risk contingency and post-award changes
· Non-contract costs such as permitting, right of way and construction management
The total project cost or total capital cost is the OPCC including soft costs:
· Engineering design
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· Engineering services during construction
· Construction management
· Permitting
4 Alternatives
This section summarizes the six (6) alternatives:
1. Alt 1: Do Nothing
2. Alt 2: Golf Course Pipeline Project
3. Alt 3: Replace All Broken Bar Wraps and Localized Cylinder Wall Loss
4. Alt 4: Alt 3 + Broken Bar Wrap
5. Alt 5: Alt 4 + Localized Cylinder Wall Loss
6. Alt 6: 100% Pipeline Replacement
4.1 Alt 1: Do Nothing
The Alternative 1 Do Nothing Alternative is reactive repairing pipeline section as it fails. This is
similar to the current practice. The historical repair costs can be adjusted for inflation and applied for
budgetary planning purposes. However, this will not be an accurate estimate going forward.
Pipeline material EUL is summarized in Table 8.
Table 8. Pipeline material EULs
Material Estimated Useful
Life (EUL)
Welded steel pipe (WSP) 50 – 70 YR
AWWA C303 bar wrapped pipe (BWP) 75-100 YR
Ductile iron pipe (DIP) 60-100+ YR
Polyvinyl chloride (PVC) 70 YR
High-density polyethylene (HDPE) 50-100 YR
The existing pipeline is approximately 65 years old. Therefore, the WSP RUL is approximately 10 to
35 years or (75 – 65) to (100 – 65). The WSP RUL is approximately -15 to +5 years. With good soil
conditions / environment, corrosion protection, and maintenance, the pipeline can last much longer
than their statistical EULs. However, as the pipeline ages and breaks, the breaks will become more
frequent, Figure 4.
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Figure 4. Relationship between historical break count and future performance
Figure 4 quantifies the relationship between historic break count and future performance for a
particular pipeline by calculating the proportion of pipeline that break again and the average duration
between subsequent breaks. This data indicates that as a pipeline experiences more breaks, the
duration until the next break becomes shorter. Both trends support the theory that historic break
count is a good indicator of future performance of a pipeline with the average break rate in California
and Nevada at 9.7 annual breaks per 100 miles per Folkman’s 2018 report titled Water Main Break
Rates in the USA and Canada: A Comprehensive Study. Average durations between subsequent
breaks shown in blue are two breaks in 6.7 years, four breaks in 3.9 years, and 11 breaks in 0.78
years. The proportions that will break again shown in orange are 47% after one break, 56% after
two breaks, and 100% after ten breaks.
Therefore, the Do Nothing Alternative is not viable due to the unpredictability, potential runaway high
maintenance and potential property damage costs, loss of service, and low of confidence by the
public and regulatory agencies. This alternative is not recommended.
4.2 Alt 2: Golf Course Pipeline Project
The Alternative 2 Golf Course Pipeline Project Alternative implements the Whale Rock Dam
Transmission Pipeline Replacement Project (STA 685+00 to 690+00) 100% Design Project, Figure
5. The construction project was previous put on hold for various reasons.
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January 2, 2025 | 11
Figure 5. Golf course pipeline project
This alternative replaces pipeline sections that have broken bar warps and localized cylinder wall
loss as previously identified by Pure Technologies, Table 9. The replacement total length of 223-FT
is greater than the identified length of 128-FT because the intermediate pipeline sections and ends
are also replaced, Figure 6. Applicable appurtenances are included in this alternative.
Table 9. Pure Technologies identified broken bar wrap and localized cylinder wall loss at golf course
Ref # Piece
#
Start
STA
Stop
STA PL L (FT) PL Mat Reported
Class
3262 737 686+59 686+90 32 BWP 340
3263 736 686+90 687+22 32 BWP 320
3264 735 687+22 687+54 32 BWP 340
3266 733 687+86 688+18 32 BWP 340
Figure 6. Sample sketch of pipeline replacement section with broken pipeline identified with red “X”.
The intermediate and end pipeline sticks will be replaced in addition to the broken pipelines.
Per 2023 Golf course pipeline project OPCC is approximately $1,071,000. With a 6% annual
escalation, the 2024 OPCC is approximately $1,136,000. However, through this OPCC effort, the
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2024 total construction OPCC is approximately $768,000 instead of $1,136,000. There total project
OPCC is approximately $1.11M.
4.3 Alt 3: Replace All Broken Bar Wraps & Localized
Cylinder Wall Loss
The Alternative 3 Replace All Broken Bar Wraps & Localized Cylinder Wall Loss is Alternative 2 with
one additional broken bar wrapped and localized cylinder wall loss pipeline section. This alternative
requires interior pipeline reinspection because reinspection is recommended every five (5) years and
because there had been an additional unidentified break.
The alternative analysis pipeline replacement priority is summarized in Table 10.
Table 10. Pipeline replacement priority
Priority Description
1 Broken bar wraps and localized cylinder wall loss
2 Broken bar wraps
3 Cylinder wall loss
Alternative 3 adds one additional location at approximately 100-FT of pipeline to Alternative 2, Table
11.
Table 11. Pure Technologies identified broken bar wrap and localized cylinder wall loss for
Alternative 3
Ref # Piece
#
Start
STA
Stop
STA PL L (FT) PL Mat Reported
Class
3262 737 686+59 686+90 32 BWP 340
3263 736 686+90 687+22 32 BWP 320
3264 735 687+22 687+54 32 BWP 340
3266 733 687+86 688+18 32 BWP 340
3496 504 759+63 759+95 32 BWP 230
The 2024 Construction and Project OPCCs are approximately $851,200 and $1,217,200,
respectively.
4.4 Alt 4: Alt 3 + Broken Bar Wrap
Alternative 4 includes all broken bar warps and localized cylinder wall loss and broken bar warps
damaged pipeline sections, Table 3 and Table 5 plus five locations and approximately 623-FT. This
alternative requires interior pipeline reinspection because reinspection is recommended every five
(5) years and because there had been an additional unidentified break. The 2024 Construction and
Project OPCCs are approximately $1.10M and $1.57M, respectively.
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4.5 Alt 5: Alt 4 + Localized Cylinder Wall Loss
Alternative 5 includes all broken bar warps and localized cylinder wall loss, broken bar warps, and
cylinder wall loss damaged pipeline sections, Table 3 to Table 5 plus fifteen locations and
approximately 2,623-FT. This alternative requires interior pipeline reinspection because reinspection
is recommended every five (5) years and since there had been an additional unidentified break.
Alternative 5 includes. The 2024 Construction and Project OPCCs are approximately $2.76M and
$3.94M, respectively.
4.6 Alt 6: 100% Pipeline Replacement
Alternative 6 eventually replaces 100% of the pipeline based on the criticality identified in Table 10
and budget constraints. This alternative requires interior pipeline reinspection because reinspection
is recommended every five (5) years and since there had been an additional unidentified break.
After reinspection, the pipeline section will be prioritized to develop a five-to-ten-year capital
improvement plan (CIP) for pipeline replacement. Near the end of the CIP, the pipeline again will be
reinspected to prioritize remaining pipeline replacement. This repeats until 100% of the pipeline will
be replaced.
Referring to Table 12, the options refer to the quantity of pipeline replacement per year and the
number of year for 100% pipeline replacement. For Alt 6 Option 3, assuming there is an annual
$2.79M budget and $3.99M for construction and project, respectively. Under Alt 6 Option 3, 100% of
the pipeline will be replaced in 25-years and 0.64 miles per year or 4.00% per year of the total
pipeline length.
Table 12. 100% pipeline replacement as a function of total replacement years
Option Replacement
(MI/YR)
Replacement
(%/YR)
# of YR for
100%
Replacement
Constr
OPCC
($/YR)
Project
OPCC
($/YR)
1 0.46 2.86 35.0 $1.99M $2.85M
2 0.53 3.33 30.0 $2.33M $3.33M
3 0.64 4.00 25.0 $2.79M $3.99M
4 0.80 5.00 20.0 $3.49M $5.00M
5 0.93 5.81 17.2 $4.06M $5.80M
6 1.07 6.67 15.0 $4.65M $6.65M
7 1.33 8.33 12.0 $5.82M $8.31M
8 1.60 10.00 10.0 $6.98M $9.98M
9 3.20 20.00 5.0 $13.95M $19.95M
10 16 100.00 1.0 $69.77M $99.77M
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4.7 Discussion
Table 12 and Appendix A opinion of probable construction costs (OPCCs) are based on traditional
cut-and-cover.
Detailed rehabilitation method (CIPP and slip lining) OPCCs are not provided because of unknown
variables required to develop reasonable accurate OPCCs in the current alternative analysis phase
included acceptable flow capacity reductions resulting from rehabilitation methods. At a high level,
the material cost for 30-IN OD non-structural lining is similar to new 30-IN diameter pipeline per
linear foot. Whereas the material cost for 30-IN OD structural lining is more than new 30-IN
diameter pipeline per linear foot. The excavation savings along the cut-and-cover pipeline alignment
are offset by the relatively large CIPP launch and receiving pits at approximately every 400-FT.
Additionally, CIPP equipment mobilization and demobilization cost is approximately $300,000.
Therefore, Alternatives 1, 2, and 3 construction OPCCs are higher for CIPP (non-structural and
structural) than traditional cut-and-cover. Alternatives 5 and 6 CIPP and cut-and-cover OPCCs
would be more similar to each other.
Slip ling and CIPP OPCCs would be more similar. However, slip lining will significantly reduce flow
rates due to the inside diameter (See Appendix B Figure 11) and potentially requiring excavation as
every elbow fittings; therefore, slip lining is not recommended for pipeline rehabilitation. Flow
capacity reductions of transmission mains are generally not preferred in the industry. Therefore, the
traditional cut-and-cover is preferred for the alternative analysis especially with a phased approach
to replace 100% of the pipeline over time.
4.8 Summary
Table 13 summarizes the pipeline replacement alternatives by method of cut-and-cover.
Table 13. Pipeline replacement alternatives summary
Alt Interior
Reinspection
# of
Location 1
Length 2
(FT)
OPCC
Construction
OPCC
Project
1 NA NA NA Unknown Unknown
2 NA 1 223 $777,800 $1.11M
3 Ö 2 323 $851,200 $1.22M
4 Ö 5 623 $1.10M $1.57M
5 Ö 15 2,623 $2.76M $3.94M
6 3 Ö Varies 3,379 $2.79M/YR $3.99M/YR
6 4 Ö Varies
323 (Yr 1) &
3,362 (Yr 2-
26)
$851,200
(Yr 1) &
$2.76M/YR
(Yr 2-25)
$1.22M
(Yr 1) &
$3.94M/YR
(Yr 2-26)
Notes:
1. Distinct locations of pipe segments
2. Approximate length
3. Assumes 100% pipeline replacement in a period of 25 years. The 100% OPCC is amortized
over the replacement period.
4. Assumes 100% pipeline replacement period of 25 years after executing Alt 3 in year one
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5. Alternatives: Alt 1-Do Nothing; Alt 2-Golf Course Pipeline Project; Alt 3-Replace All Broken Bar
Wraps and Localized Cylinder Wall Loss; Alt 4-Alt 3 + Broken Bar Wrap; Alt 5-Alt 4 + Localized
Cylinder Wall Loss; Alt 6-100% Pipeline Replacement
5 Recommendation
The recommendations are to first execute Alternate 3: Replace All Broken Bar Wraps & Localized
Cylinder Wall Loss, then reinspect the pipeline, and execute Alternative 6: 100% Pipeline
Replacement. The recommended installation method is cut-and-cover.
The recommendation Year One (Alternate 3) costs are approximately $851,200 and $1.22M for
construction and project costs, respectively. The recommendation Year 2 to 26 (Alternative 6 minus
Alternative 3) costs are approximately $2.76M/YR and $3.94M/YR for construction and project costs,
respectively.
6 References
1. List of Whale Rock Pipeline Leaks since 2013 (2013 to 2023)
2. Whale Rock Dam – Transmission Pipeline Replacement Project, November 2022 (Golf
Course Pipeline Project)
3. Condition Assessment of 30-Inch Whale Rock Conveyance Conduit V 2.0, Pure
Technologies, a Xylem brand, December 2019
4. Whale Rock Pipeline Relocation Project, Plans for the Construction of a 30 Inch Raw Water
Pipeline, 11 pages, Parsons Engineering Science, Inc., October 1999
5. Whale Rock Conveyance Conduit Plan and Profile STA 0+00 to STA 903+78 As-Built
Drawings, 80 pages, State of California Department of Water Resources Southern California
District, 1959
List of Appendices
Appendix A Opinion of Probable Construction Cost (OPCC)
Appendix B Hydraulic Analysis
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Appendix A. OPCC
Notes on opinion of probable construction cost (OPCC) development:
1. The 30 IN pipeline (pipeline) conveys raw water from Whale Rock Reservoir to the San Luis
Obispo Treatment Plant for a total distance of approximately 16 miles
2. Pipeline material:
a. Existing AWWA M11 welded steel pipeline (WSP) is approximately 18,321-FT, 3.47 mile,
or 21.9% of total length
b. Existing AWWA C-303 bar wrapped concrete cylinder pipeline (BWP) is approximately
65,523-FT, 12.41 mile, or 78.1% of total length
c. Replacement pipe is 100% AWWA C151 ductile iron pipe
3. Pipeline outside diameter:
a. Existing AWWA M11 outside diameter is unknown
b. Existing AWWA C-303 BWP has maximum outside diameter of 35-IN
c. For OPCC, replacement pipe is AWWA C151 ductile iron pipe has outside diameter of
32-IN
4. Pipeline installation:
a. The pipeline is installed in paved road approximately 2.5 mile or 15.6%
b. The pipeline is installed in unpaved road approximately 13.5 mile or 84.4%
c. Pipeline installed in paved road schematic and quantities per linear foot are shown in
Figure 7 and Table 14, respectively
d. Pipeline installed in unpaved road schematic and quantities per linear foot are shown in
Figure 8 and Table 15, respectively
5. Pipeline appurtenances
a. Appurtenances (isolation valves, air release / vacuum valves, blowoffs, etc.) are
assumed to be 20% of pipeline OPCC
b. Pipeline restraints (thrust blocks, collars, fasteners, harness, tie rods, etc.) are assumed
to be 5% of pipeline OPCC
c. Pipeline cathodic protection (bond straps, galvanic anode system, polyethylene
encasement, etc.) is assumed to be 5% of pipeline OPCC
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6. Miscellaneous:
a. Trench box / shoring box assumed
b. No dewatering and water treatment required
c. The cost for pipeline reinspection is excluded
d. Traffic control is assumed to be 10% of paved pipeline OPCC
e. Golf course lost income and site restoration are assumed at $250,000
7. OPCC:
a. AACE International class 5 with an accuracy range of -50% to +100%
b. Material and labor total costs are based on RSMeansOnline.com
c. This OPCC is for capital improvement projects (CIP)
8. Exclusions:
a. CIPP OPCC was excluded due to too many variables and unknown unknows
b. Slip lining OPCC was excluded due to too many variables and unknown unknows
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Figure 7. Pipeline installed in paved road schematic
Table 14. Pipeline installed in paved road per linear foot
DESCRIPTION
AREA VOLUME
(IN^2) (FT^2) (FT^3) (YD^3)
PAVEMENT 332.48 2.31 2.31 0.086
"T" SECTION (WINGS) 192.96 1.34 1.34 0.05
NATIVE 3953 27.45 27.45 1.02
BACKFILL 0 0 0 0
PIPE 962.11 6.68 6.68 0.25
BEDDING 708 4.92 4.92 0.18
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Figure 8. Pipeline installed in unpaved road schematic
Table 15. Pipeline installed in unpaved road per linear foot
DESCRIPTION
AREA VOLUME
(IN^2) (FT^2) (FT^3) (YD^3)
PAVEMENT 0 0 0 0
"T" SECTION (WINGS) 0 0 0 0
NATIVE 4189 29.1 29.1 1.08
BACKFILL 0 0 0 0
PIPE 962.1128 6.68 6.68 0.25
BEDDING 708 4.92 4.92 0.18
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Table 16. Alternative OPCC summary
Description Alt 2 Alt 3 Alt 4 Alt 5 Alt 6A Alt 6B
Subtotal Constr Cost $332,400 $363,758 $469,508 $1,178,371 $29,452,432 $29,814,674
General
Conditions (10%) $33,240 $36,376 $46,951 $117,837 $2,945,243 $2,981,467
Contractor
OH&P (12%) $39,888 $43,651 $56,341 $141,405 $3,534,292 $3,577,761
Mob / Demob
(5%) $16,620 $18,188 $23,475 $58,919 $1,472,622 $1,490,734
Bonds and
Insurance (3%) $9,972 $10,913 $14,085 $35,351 $883,573 $894,440
Subtotal $432,121 $472,885 $610,361 $1,531,883 $38,288,161 $38,759,077
Contingency
(50%) $216,060 $236,443 $305,181 $765,941 $19,144,081 $19,379,538
Subtotal w/
Contingency $648,181 $709,328 $915,542 $2,297,824 $57,432,242 $58,138,615
Mkt Volatility
Adj (20%) $129,636 $141,866 $183,108 $459,565 $11,486,448 $11,627,723
Total Construction
Cost $777,817 $851,194 $1,098,650 $2,757,389 $68,918,690 $69,766,338
High End of
Range (100%) $1,555,634 $1,702,387 $2,197,300 $5,514,778 $137,837,381 $139,532,676
Low End of
Range (-50%) $388,909 $425,597 $549,325 $1,378,695 $34,459,345 $34,883,169
Total Project Cost
Engineering
Design (12%) $93,338 $102,143 $131,838 $330,887 $8,270,243 $8,371,961
Engr Serv Sur
Constr (10%) $77,782 $85,119 $109,865 $275,739 $6,891,869 $6,976,634
Constr
Mgmt (15%) $116,673 $127,679 $164,797 $413,608 $10,337,804 $10,464,951
Permitting
(Excl Envir) (6%) $46,669 $51,072 $65,919 $165,443 $4,135,121 $4,185,980
Total Capital Cost $1,112,279 $1,217,207 $1,571,069 $3,943,066 $98,553,727 $99,765,863
High End of
Range (100%) $2,224,557 $2,434,414 $3,142,138 $7,886,133 $197,107,454 $199,531,726
Low End of
Range (-50%) $556,139 $608,603 $785,535 $1,971,533 $49,276,864 $49,882,932
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Table 17. Alt 2: Golf Course Pipeline Project OPCC
Item Description QT Unit Unit Cost Total Cost Comments
2 - Existing Conditions
2.1 Demolition, saw cutting, asphalt, <=3" deep 0 LF $1.63 $0.00 Paved
2.2 Demolish, piping & fittings, 30" diameter 234 LF $15.85 $3,708.90
2.3 Disposal: (E) pavement, bedding & pipeline 100 CY $15.36 $1,536.00
3 - Concrete
3.1 Sand, washed, for pipeline bedding (new) 43 CY 56.64 $2,415.13
13 - Special Construction
13.1
Pipeline cathodic protection: bond straps, galvanic
anode system, polyethylene encasement, etc. at m % of
PL length 1 LS $3,000 $3,000.00 5%
22 - Plumbing
22.1
Appurtenances: isolation valves, air release/vacuum
valves, blowoffs, etc. at n % of PL length 1 LS $11,000 $11,000.00 20%
31 - Earthwork
31.1
Excavation, trench, loam or sandy clay, 1 C.Y. excavator,
<=6' deep 300 CY $4.44 $1,332.00 Unpaved portion
31.2
Excavation, trench, loam or sandy clay, 1 C.Y. excavator,
<=6' deep 0 CY $4.44 $0.00 Paved portion
31.3 Hauling, 30 min/load/unload, 8 CY truck, 8 mi, 30 MPH 0 CY $10.97 $0.00
(E) pavement & bedding
for disposal
31.4 Hauling, 30 min/load/unload, 8 CY truck, 8 mi, 30 MPH 100 CY $10.97 $1,097.00 (E) pipeline for disposal
31.5 Backfill, sand and native, 300 HP dozer, 50' haul 300 CY $0.68 $204.00
31.6
Compaction, 4 passes, 6" lifts, riding, sheepsfoot or
wobbly wheel roller 600 CY $0.99 $594.00
32 - Exterior Improvements
32.1
Asphalt paving, plant mixed asphaltic base courses for
roadways, 4" thick 0 SY $25.79 $0.00
32.2 Golf course lost of income and site restoration 1 LS $250,000.00 $250,000.00 $250,000
33 - Utilities
33.1
Piping, ductile iron, mechnical joint, cement lined, 30"
diameter 234 LF $228.69 $53,513.46
33.2
Pipeline restraints: thrust blocks, collars, fasteners,
harness, tie rods, etc. at p % of PL length 1 LS $3,000 $3,000.00 5%
34 - Transportation
34.1 Traffic control at q % of paved PL length 1 LS $1,000 $1,000.00 10%
Subtotal Construction Cost $332,400.49
General Conditions 10% $33,240.05
Contractor OH&P 12% $39,888.06
Mobilization/Demobilization 5% $16,620.02
Bonds and Insurance 3% $9,972.01
Subtotal $432,120.64
Contingency 50% $216,060.32
Subtotal w/ Contingency $648,180.95
Market Volatility Adjustment 20% $129,636.19
Total Construction Cost $777,817.15 $3,324.00/LF
High End of Range 100% $1,555,634.29 $6,648.01/LF
Low End of Range -50% $388,908.57 $1,662.00/LF
Total Project Cost
Engineering Design 12% $93,338.06
Engineering Services During Construction 10% $77,781.71
Construction Management 15% $116,672.57
Permitting (Excluding Environmental) 6% $46,669.03
Total Capital Cost $1,112,278.52 $4,753.33/LF
High End of Range 100% $2,224,557.04 $9,506.65/LF
Low End of Range -50% $556,139.26 $2,376.66/LF
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Table 18. Alt 3: Replace All Broken Bar Wraps and Localized Cylinder Wall Loss OPCC
Item Description QT Unit Unit Cost Total Cost Comments
2 - Existing Conditions
2.1 Demolition, saw cutting, asphalt, <=3" deep 0 LF $1.63 $0.00 Paved
2.2 Demolish, piping & fittings, 30" diameter 324 LF $15.85 $5,135.40
2.3 Disposal: (E) pavement, bedding & pipeline 100 CY $15.36 $1,536.00
3 - Concrete
3.1 Sand, washed, for pipeline bedding (new) 59 CY 56.64 $3,344.03
13 - Special Construction
13.1
Pipeline cathodic protection: bond straps, galvanic
anode system, polyethylene encasement, etc. at m % of
PL length 1 LS $4,000 $4,000.00 5%
22 - Plumbing
22.1
Appurtenances: isolation valves, air release/vacuum
valves, blowoffs, etc. at n % of PL length 1 LS $15,000 $15,000.00 20%
31 - Earthwork
31.1
Excavation, trench, loam or sandy clay, 1 C.Y. excavator,
<=6' deep 500 CY $4.44 $2,220.00 Unpaved portion
31.2
Excavation, trench, loam or sandy clay, 1 C.Y. excavator,
<=6' deep 0 CY $4.44 $0.00 Paved portion
31.3 Hauling, 30 min/load/unload, 8 CY truck, 8 mi, 30 MPH 0 CY $10.97 $0.00
(E) pavement & bedding
for disposal
31.4 Hauling, 30 min/load/unload, 8 CY truck, 8 mi, 30 MPH 100 CY $10.97 $1,097.00 (E) pipeline for disposal
31.5 Backfill, sand and native, 300 HP dozer, 50' haul 500 CY $0.68 $340.00
31.6
Compaction, 4 passes, 6" lifts, riding, sheepsfoot or
wobbly wheel roller 1,000 CY $0.99 $990.00
32 - Exterior Improvements
32.1
Asphalt paving, plant mixed asphaltic base courses for
roadways, 4" thick 0 SY $25.79 $0.00
32.2 Golf course lost of income and site restoration 1 LS $250,000.00 $250,000.00 $250,000
33 - Utilities
33.1
Piping, ductile iron, mechnical joint, cement lined, 30"
diameter 324 LF $228.69 $74,095.56
33.2
Pipeline restraints: thrust blocks, collars, fasteners,
harness, tie rods, etc. at p % of PL length 1 LS $4,000 $4,000.00 5%
34 - Transportation
34.1 Traffic control at q % of paved PL length 1 LS $2,000 $2,000.00 10%
Subtotal Construction Cost $363,757.99
General Conditions 10% $36,375.80
Contractor OH&P 12% $43,650.96
Mobilization/Demobilization 5% $18,187.90
Bonds and Insurance 3% $10,912.74
Subtotal $472,885.38
Contingency 50% $236,442.69
Subtotal w/ Contingency $709,328.07
Market Volatility Adjustment 20% $141,865.61
Total Construction Cost $851,193.69 $2,627.14/LF
High End of Range 100% $1,702,387.37 $5,254.28/LF
Low End of Range -50% $425,596.84 $1,313.57/LF
Total Project Cost
Engineering Design 12% $102,143.24
Engineering Services During Construction 10% $85,119.37
Construction Management 15% $127,679.05
Permitting (Excluding Environmental) 6% $51,071.62
Total Capital Cost $1,217,206.97 $3,756.81/LF
High End of Range 100% $2,434,413.94 $7,513.62/LF
Low End of Range -50% $608,603.49 $1,878.41/LF
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Table 19. Alt 4: Alt 3 + Broken Bar Wrap OPCC
Item Description QT Unit Unit Cost Total Cost Comments
2 - Existing Conditions
2.1 Demolition, saw cutting, asphalt, <=3" deep 0 LF $1.63 $0.00 Paved
2.2 Demolish, piping & fittings, 30" diameter 630 LF $15.85 $9,985.50
2.3 Disposal: (E) pavement, bedding & pipeline 200 CY $15.36 $3,072.00
3 - Concrete
3.1 Sand, washed, for pipeline bedding (new) 115 CY 56.64 $6,502.27
13 - Special Construction
13.1
Pipeline cathodic protection: bond straps, galvanic
anode system, polyethylene encasement, etc. at m % of
PL length 1 LS $8,000 $8,000.00 5%
22 - Plumbing
22.1
Appurtenances: isolation valves, air release/vacuum
valves, blowoffs, etc. at n % of PL length 1 LS $29,000 $29,000.00 20%
31 - Earthwork
31.1
Excavation, trench, loam or sandy clay, 1 C.Y. excavator,
<=6' deep 800 CY $4.44 $3,552.00 Unpaved portion
31.2
Excavation, trench, loam or sandy clay, 1 C.Y. excavator,
<=6' deep 0 CY $4.44 $0.00 Paved portion
31.3 Hauling, 30 min/load/unload, 8 CY truck, 8 mi, 30 MPH 0 CY $10.97 $0.00
(E) pavement & bedding
for disposal
31.4 Hauling, 30 min/load/unload, 8 CY truck, 8 mi, 30 MPH 200 CY $10.97 $2,194.00 (E) pipeline for disposal
31.5 Backfill, sand and native, 300 HP dozer, 50' haul 800 CY $0.68 $544.00
31.6
Compaction, 4 passes, 6" lifts, riding, sheepsfoot or
wobbly wheel roller 1,600 CY $0.99 $1,584.00
32 - Exterior Improvements
32.1
Asphalt paving, plant mixed asphaltic base courses for
roadways, 4" thick 0 SY $25.79 $0.00
32.2 Golf course lost of income and site restoration 1 LS $250,000.00 $250,000.00 $250,000
33 - Utilities
33.1
Piping, ductile iron, mechnical joint, cement lined, 30"
diameter 630 LF $228.69 $144,074.70
33.2
Pipeline restraints: thrust blocks, collars, fasteners,
harness, tie rods, etc. at p % of PL length 1 LS $8,000 $8,000.00 5%
34 - Transportation
34.1 Traffic control at q % of paved PL length 1 LS $3,000 $3,000.00 10%
Subtotal Construction Cost $469,508.47
General Conditions 10% $46,950.85
Contractor OH&P 12% $56,341.02
Mobilization/Demobilization 5% $23,475.42
Bonds and Insurance 3% $14,085.25
Subtotal $610,361.01
Contingency 50% $305,180.51
Subtotal w/ Contingency $915,541.52
Market Volatility Adjustment 20% $183,108.30
Total Construction Cost $1,098,649.82 $1,743.89/LF
High End of Range 100% $2,197,299.65 $3,487.78/LF
Low End of Range -50% $549,324.91 $871.94/LF
Total Project Cost
Engineering Design 12% $131,837.98
Engineering Services During Construction 10% $109,864.98
Construction Management 15% $164,797.47
Permitting (Excluding Environmental) 6% $65,918.99
Total Capital Cost $1,571,069.25 $2,493.76/LF
High End of Range 100% $3,142,138.50 $4,987.52/LF
Low End of Range -50% $785,534.62 $1,246.88/LF
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Table 20. Alt 5: Alt 4 + Localized Cylinder Wall Loss OPCC
Item Description QT Unit Unit Cost Total Cost Comments
2 - Existing Conditions
2.1 Demolition, saw cutting, asphalt, <=3" deep 900 LF $1.63 $1,467.00 Paved
2.2 Demolish, piping & fittings, 30" diameter 2,628 LF $15.85 $41,653.80
2.3 Disposal: (E) pavement, bedding & pipeline 1,100 CY $15.36 $16,896.00
3 - Concrete
3.1 Sand, washed, for pipeline bedding (new) 479 CY 56.64 $27,123.76
13 - Special Construction
13.1
Pipeline cathodic protection: bond straps, galvanic
anode system, polyethylene encasement, etc. at m % of
PL length 1 LS $31,000 $31,000.00 5%
22 - Plumbing
22.1
Appurtenances: isolation valves, air release/vacuum
valves, blowoffs, etc. at n % of PL length 1 LS $121,000 $121,000.00 20%
31 - Earthwork
31.1
Excavation, trench, loam or sandy clay, 1 C.Y. excavator,
<=6' deep 2,800 CY $4.44 $12,432.00 Unpaved portion
31.2
Excavation, trench, loam or sandy clay, 1 C.Y. excavator,
<=6' deep 600 CY $4.44 $2,664.00 Paved portion
31.3 Hauling, 30 min/load/unload, 8 CY truck, 8 mi, 30 MPH 400 CY $10.97 $4,388.00
(E) pavement & bedding
for disposal
31.4 Hauling, 30 min/load/unload, 8 CY truck, 8 mi, 30 MPH 700 CY $10.97 $7,679.00 (E) pipeline for disposal
31.5 Backfill, sand and native, 300 HP dozer, 50' haul 3,400 CY $0.68 $2,312.00
31.6
Compaction, 4 passes, 6" lifts, riding, sheepsfoot or
wobbly wheel roller 6,800 CY $0.99 $6,732.00
32 - Exterior Improvements
32.1
Asphalt paving, plant mixed asphaltic base courses for
roadways, 4" thick 350 SY $25.79 $9,026.50
32.2 Golf course lost of income and site restoration 1 LS $250,000.00 $250,000.00 $250,000
33 - Utilities
33.1
Piping, ductile iron, mechnical joint, cement lined, 30"
diameter 2,628 LF $228.69 $600,997.32
33.2
Pipeline restraints: thrust blocks, collars, fasteners,
harness, tie rods, etc. at p % of PL length 1 LS $31,000 $31,000.00 5%
34 - Transportation
34.1 Traffic control at q % of paved PL length 1 LS $12,000 $12,000.00 10%
Subtotal Construction Cost $1,178,371.38
General Conditions 10% $117,837.14
Contractor OH&P 12% $141,404.57
Mobilization/Demobilization 5% $58,918.57
Bonds and Insurance 3% $35,351.14
Subtotal $1,531,882.80
Contingency 50% $765,941.40
Subtotal w/ Contingency $2,297,824.20
Market Volatility Adjustment 20% $459,564.84
Total Construction Cost $2,757,389.04 $1,049.23/LF
High End of Range 100% $5,514,778.07 $2,098.47/LF
Low End of Range -50% $1,378,694.52 $524.62/LF
Total Project Cost
Engineering Design 12% $330,886.68
Engineering Services During Construction 10% $275,738.90
Construction Management 15% $413,608.36
Permitting (Excluding Environmental) 6% $165,443.34
Total Capital Cost $3,943,066.32 $1,500.41/LF
High End of Range 100% $7,886,132.64 $3,000.81/LF
Low End of Range -50% $1,971,533.16 $750.20/LF
Page 108 of 141
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Alternative Analysis Report
A-10 | January 2, 2025
Table 21. Alt 6A: 100% Pipeline Replacement minus Alt 3 OPCC
Item Description QT Unit Unit Cost Total Cost Comments
2 - Existing Conditions
2.1 Demolition, saw cutting, asphalt, <=3" deep 26,300 LF $1.63 $42,869.00 Paved
2.2 Demolish, piping & fittings, 30" diameter 84,048 LF $15.85 $1,332,160.80
2.3 Disposal: (E) pavement, bedding & pipeline 32,200 CY $15.36 $494,592.00
3 - Concrete
3.1 Sand, washed, for pipeline bedding (new) 15,315 CY 56.64 $867,465.01
13 - Special Construction
13.1
Pipeline cathodic protection: bond straps, galvanic
anode system, polyethylene encasement, etc. at m % of
PL length 1 LS $962,000 $962,000.00 5%
22 - Plumbing
22.1
Appurtenances: isolation valves, air release/vacuum
valves, blowoffs, etc. at n % of PL length 1 LS $3,845,000 $3,845,000.00 20%
31 - Earthwork
31.1
Excavation, trench, loam or sandy clay, 1 C.Y. excavator,
<=6' deep 89,400 CY $4.44 $396,936.00 Unpaved portion
31.2
Excavation, trench, loam or sandy clay, 1 C.Y. excavator,
<=6' deep 16,600 CY $4.44 $73,704.00 Paved portion
31.3 Hauling, 30 min/load/unload, 8 CY truck, 8 mi, 30 MPH 11,400 CY $10.97 $125,058.00
(E) pavement & bedding
for disposal
31.4 Hauling, 30 min/load/unload, 8 CY truck, 8 mi, 30 MPH 20,800 CY $10.97 $228,176.00 (E) pipeline for disposal
31.5 Backfill, sand and native, 300 HP dozer, 50' haul 106,000 CY $0.68 $72,080.00
31.6
Compaction, 4 passes, 6" lifts, riding, sheepsfoot or
wobbly wheel roller 212,000 CY $0.99 $209,880.00
32 - Exterior Improvements
32.1
Asphalt paving, plant mixed asphaltic base courses for
roadways, 4" thick 10,220 SY $25.79 $263,573.80
32.2 Golf course lost of income and site restoration 0 LS $0.00 $0.00 $250,000
33 - Utilities
33.1
Piping, ductile iron, mechnical joint, cement lined, 30"
diameter 84,048 LF $228.69 $19,220,937.12
33.2
Pipeline restraints: thrust blocks, collars, fasteners,
harness, tie rods, etc. at p % of PL length 1 LS $962,000 $962,000.00 5%
34 - Transportation
34.1 Traffic control at q % of paved PL length 1 LS $356,000 $356,000.00 10%
Subtotal Construction Cost $29,452,432
General Conditions 10% $2,945,243
Contractor OH&P 12% $3,534,292
Mobilization/Demobilization 5% $1,472,622
Bonds and Insurance 3% $883,573
Subtotal $38,288,161
Contingency 50% $19,144,081
Subtotal w/ Contingency $57,432,242
Market Volatility Adjustment 20% $11,486,448
Total Construction Cost $68,918,690 $819.99/LF
High End of Range 100% $137,837,381 $1,639.98/LF
Low End of Range -50% $34,459,345 $410.00/LF
Total Project Cost
Engineering Design 12% $8,270,243
Engineering Services During Construction 10% $6,891,869
Construction Management 15% $10,337,804
Permitting (Excluding Environmental) 6% $4,135,121
Total Capital Cost $98,553,727 $1,172.59/LF
High End of Range 100% $197,107,454 $2,345.18/LF
Low End of Range -50% $49,276,864 $586.29/LF
Page 109 of 141
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Alternative Analysis Report
January 2, 2025 | A-11
Table 22. Alt 6B 100% Pipeline Replacement OPCC
Item Description QT Unit Unit Cost Total Cost Comments
2 - Existing Conditions
2.1 Demolition, saw cutting, asphalt, <=3" deep 26,400 LF $1.63 $43,032.00 Paved
2.2 Demolish, piping & fittings, 30" diameter 84,372 LF $15.85 $1,337,296.20
2.3 Disposal: (E) pavement, bedding & pipeline 32,300 CY $15.36 $496,128.00
3 - Concrete
3.1 Sand, washed, for pipeline bedding (new) 15,374 CY 56.64 $870,809.04
13 - Special Construction
13.1
Pipeline cathodic protection: bond straps, galvanic
anode system, polyethylene encasement, etc. at m % of
PL length 1 LS $965,000 $965,000.00 5%
22 - Plumbing
22.1
Appurtenances: isolation valves, air release/vacuum
valves, blowoffs, etc. at n % of PL length 1 LS $3,860,000 $3,860,000.00 20%
31 - Earthwork
31.1
Excavation, trench, loam or sandy clay, 1 C.Y. excavator,
<=6' deep 89,700 CY $4.44 $398,268.00 Unpaved portion
31.2
Excavation, trench, loam or sandy clay, 1 C.Y. excavator,
<=6' deep 16,700 CY $4.44 $74,148.00 Paved portion
31.3 Hauling, 30 min/load/unload, 8 CY truck, 8 mi, 30 MPH 11,400 CY $10.97 $125,058.00
(E) pavement & bedding
for disposal
31.4 Hauling, 30 min/load/unload, 8 CY truck, 8 mi, 30 MPH 20,900 CY $10.97 $229,273.00 (E) pipeline for disposal
31.5 Backfill, sand and native, 300 HP dozer, 50' haul 106,400 CY $0.68 $72,352.00
31.6
Compaction, 4 passes, 6" lifts, riding, sheepsfoot or
wobbly wheel roller 212,800 CY $0.99 $210,672.00
32 - Exterior Improvements
32.1
Asphalt paving, plant mixed asphaltic base courses for
roadways, 4" thick 10,260 SY $25.79 $264,605.40
32.2 Golf course lost of income and site restoration 1 LS $250,000.00 $250,000.00 $250,000
33 - Utilities
33.1
Piping, ductile iron, mechnical joint, cement lined, 30"
diameter 84,372 LF $228.69 $19,295,032.68
33.2
Pipeline restraints: thrust blocks, collars, fasteners,
harness, tie rods, etc. at p % of PL length 1 LS $965,000 $965,000.00 5%
34 - Transportation
34.1 Traffic control at q % of paved PL length 1 LS $358,000 $358,000.00 10%
Subtotal Construction Cost $29,814,674
General Conditions 10% $2,981,467
Contractor OH&P 12% $3,577,761
Mobilization/Demobilization 5% $1,490,734
Bonds and Insurance 3% $894,440
Subtotal $38,759,077
Contingency 50% $19,379,538
Subtotal w/ Contingency $58,138,615
Market Volatility Adjustment 20% $11,627,723
Total Construction Cost $69,766,338 $826.89/LF
High End of Range 100% $139,532,676 $1,653.78/LF
Low End of Range -50% $34,883,169 $413.44/LF
Total Project Cost
Engineering Design 12% $8,371,961
Engineering Services During Construction 10% $6,976,634
Construction Management 15% $10,464,951
Permitting (Excluding Environmental) 6% $4,185,980
Total Capital Cost $99,765,863 $1,182.45/LF
High End of Range 100% $199,531,726 $2,364.90/LF
Low End of Range -50% $49,882,932 $591.23/LF
Page 110 of 141
Page 111 of 141
Whale Rock Dam –Pipeline Replacement Study
Alternative Analysis Report
January 2, 2025 | B-1
Appendix B. Hydraulic Analysis
As part of the scope of work, this section summarizes the high level hydraulic analysis considering
theoretical flow capacities, pipeline diameters, materials, and pressure ratings, elevations, and pump
station operations based on piping replacement, structural lining techniques, and slip lining
techniques. Whereas a detailed hydraulic analysis requires more in-depth examination of the
aforementioned.
The hydraulic analysis was created as a Microsoft Excel spreadsheet with Swanee-Jain equation
used to solved directly for the Darcy-Weisbach friction factor, Figure 9. Minor loses were assumed
to be a percentage of major loses. Only the approximate start (EL 187 FT), end (EL 420 FT), and
highest (EL 540 FT) elevations were considered with values determined from as-built drawings and
Google Earth, Figure 10. The pipeline segments were assumed to have their full pressure ratings
assuming the deteriorated segments are replaced for non-structural CIPP and slip lining pipeline
renovation. The pipeline pressure rating was 230 to 500 PSI with the higher pressure rating
immediately downstream of the booster pump station. The entire length of the pipeline was
assumed to have the homogeneous/same diameter. The booster pump station was assumed to be
upgraded as required. This hydraulics analysis excludes surge / transient pressure analysis that
could be significant due to volumes and velocities conveyed.
Figure 9. Whale Rock Pipeline MS Excel hydraulic analysis spreadsheet for analyzing hydraulic
performance with potential reduced pipeline inside diameters
Page 112 of 141
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Alternative Analysis Report
B-2 | January 2, 2025
Figure 10. Pipeline alignment and elevations from Google Earth
The Whale Rock Pipeline hydraulic analysis results in graphic format is illustrated in Figure 11. The
x-axis represents the booster pump station pumping flow rate in million gallon per day (MGD). The
y-axis represents the energy, head, or total dynamic head (TDH) the booster pump station must add
to convey given flow rates from Whale Rock Reservoir to the San Luis Obispo Treatment Plant. The
booster pump station must provide a minimum head of approximately 150 PSI to overcome the static
elevation head from Whale Rock Reservoir to the San Luis Obispo Treatment Plant and the highest
elevation.
Page 113 of 141
Whale Rock Dam –Pipeline Replacement Study
Alternative Analysis Report
January 2, 2025 | B-3
Figure 11. Whale Rock Pipeline hydraulic analysis results in graphical format. 30-IN ID blue line
represents original pipeline. 25-IN ID with 30-IN OD red line represents 100% length structural CIPP
rehabilitation. 20-IN ID with 24-IN OD green line represents 100% length structural HDPE pipeline
slip lining. 15-IN ID with 20-IN OD yellow line represents 100% length structural HDPE pipeline slip
lining.
Figure 11 blue line represents the existing theoretical 30-in diameter pipeline. The theoretical
hydraulic limitations are either the booster pump station pump TDH, pipeline pressure rating
including surge pressure, and/or recommended flow velocity. Assuming a recommended maximum
flow velocity of seven feet per second (FT/S), the maximum theoretical flow rate results in the pump
TDH and pipeline pressure ratings exceeding system design and acceptable ranges. Therefore,
recommend maximum velocity will not be the limiting factor. Existing pipeline pressure rating ranges
from 230 to 500 PSI. Assuming, a pipeline maximum pressure rating of 500 PSI (outside the range
of Figure 11) results in flow velocity and rate of approximately 6.3 FT/S and 20 MGD, respectively.
However, 500 PSI exceeds the existing booster pump station TDH and reasonable new pump TDH.
Assuming a maximum pipeline pressure rating is 230 PSI (minimum pressure rating of the existing
pipeline as new pipeline), the flow velocity and rate are limited to approximately 5.0 FT/S and 10
MGD, respectively. 230 PSI could result in a reasonable pump TDH assuming the pipelines are at
their full pressure rating excluding surges. However, with the existing pipeline deteriorated
conditions, the unknown wall loss depths, and without having performed a surge analysis, the
pipeline flow velocities and rates should be reduced, resulting in reduced pump station TDH and
resulting surges,
Page 114 of 141
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Alternative Analysis Report
B-4 | January 2, 2025
Table 23.
Page 115 of 141
Whale Rock Dam –Pipeline Replacement Study
Alternative Analysis Report
January 2, 2025 | B-5
Table 23. 30-IN diameter pipeline reduced flow rates, velocities, and TDHs
Q (MGD) V (FT/S) TDH (FT) TDH (PSI)
4.0 1.26 389 169
4.5 1.42 397 172
5.0 1.56 406 176
5.5 1.73 416 180
6.0 1.89 427 185
Figure 11 red line represents the existing 30-in diameter pipeline with 2.5-IN thick CIPP lining
reducing pipeline inside diameter to 25-IN.
Table 24 summarizes HDPE iron pipe size (IPS) pressure pipe dimensional ratio (DR) and
diameters.
Table 24. HDPE IPS Pressure Pipe DR and diameters for slip lining
Outside Diameter (OD)
28 26 24 20
DR 9
(250 PSI)
Min Wall 3.111 2.889 2.667 2.222
Avg ID 21.40 19.88 18.35 15.29
DR 11
(200 PSI)
Min Wall 2.545 2.364 2.182 1.818
Avg ID 22.60 20.99 19.37 16.15
DR 13.5
(160 PSI)
Min Wall 2.074 1.926 1.778 1.481
Avg ID 23.60 21.92 20.23 16.86
Figure 11 green line represents the existing 30-IN diameter pipeline with HDPE 24-OD, 20-IN ID, DR
13.5 (160 PSI) slip lining with the existing 30-IN diameter pipeline casing as the structural member.
Figure 11 yellow line represents the existing 30-IN diameter pipeline with HDPE 20-IN OD, 15-IN ID,
DR 9 (250 PSI) slip lining with the HDPE slip lined pipeline as the structural member.
It is assumed that a relatively more rigid 20-IN OD HDPE DR-9 or less rigid 24-IN OD HDPE DR
13.5 slip lining can accommodate the existing 30-IN diameter pipeline joint deflections without
significant additional launching pits, whereas, 26 and 28-IN OD HDPE pipelines are too large in
diameters to accommodate the existing 30-IN diameter pipeline joint deflections requiring significant
additional launching pits.
Figure 11 red, green, and yellow lines assume that 100% of the 30-IN diameter pipeline length are
structurally CIPP or slip lined. 100% length structurally CIPP or slip lining are unlikely due to
relatively high costs and reduction in hydraulic performance. It is more likely that structurally CIPP
or slip lining will be applied as a phased approach similar to Alternative 6. Assuming if 50% of the
30-IN diameter pipeline length is eventually structurally slip lined with 20-IN ID pipeline, graphically
the hydraulic performance could be represented in Figure 11 as the 25-IN ID red line. However, if
structurally CIPP or slip lining will be applied as a phased approach, there will be significant costs for
mobilization with CIPP mobilization at approximately $300,000 per project.
Page 116 of 141