HomeMy WebLinkAboutUtilities 2013-02-19 Item 2B - Discussion - Sanitary Sewer Comprehensive Plan Update for Capital Improvement ProjectsTO:
City of Tukwila
Jim Haggerton, Mayor
INFORMATIONAL MEMORANDUM
Mayor Haggerton
Utilities Committee
FROM: Bob Giberson, Public Works Director
BY: Mike Cusick, Senior Engineer
DATE: February 15, 2013
SUBJECT: Sewer Comprehensive Plan
Project No. 91040101
Sanitary Sewer Comprehensive Plan Update for Capital Improvement Projects
ISSUE
New capital projects for sanitary sewer based on the Comprehensive Sewer Plan.
BACKGROUND
In 2010 the City contracted with Carollo Engineers to update the Sanitary Sewer Comprehensive Plan.
DISCUSSION
Carollo Engineers has recommended that the following projects be added to the Capital Improvement Program (CIP):
1) The Comprehensive Plan recommends that future Lift Station No. 13 be installed in the City owned right -of -way, just
east of Schneider Homes located at 6510 Southcenter Blvd. Sewer Lift Station No. 13 will take sewage flows from
Old Tukwila Hill, which currently runs under 1 -405 to Lift Station No. 12, located just south of the Post Office to
Southcenter Blvd., then to the existing Metro sewer line, which crosses under 1 -5 near the 15200 block of Macadam
Rd S. The scope of work also includes an upgrade to the gravity sewer line on Southcenter Blvd. (Pages 121 & 122
of the 2013 -2018 CIP).
2) Carollo Engineers is also recommending that the sanitary sewer system be modeled to ensure that it is not over
capacity in the next Sewer System update, scheduled for 2017. In Chapter 6 of the 2005 Sewer Comprehensive
Plan, sewer pipes in the CBD were flowing at lower than 60% capacity.
Future CIP Projects:
A. Replacement of Sewer Lift Stations No. 5 and No. 6 in the year 2025. These two sewer lift stations were
installed in 1975 for Fort Dent Park and Starfire and will reach the end of their life cycle in 2025.
B. Replacement of pumps in Sewer Lift Stations No. 8 and No. 10 in the year 2027. These two sewer lift stations
were installed in 2007 in Allentown and Foster Point neighborhoods.
C. Replacement of pumps in Sewer Lift Station No. 11 in the year 2032. This sewer lift station was installed in
2012 for Tukwila South.
D. Annual replacement of pipes. The consultant is recommending that the City replace aging sewer pipes near
the end of their life cycle. This is currently underway with the CBD Sanitary Sewer Rehabilitation Project.
RECOMMENDATION
For information only.
Attachment: Sewer Comprehensive Plan, Chapter 7, pages 4 -6
2013 -2018 CIP Pages 121, 122, & 117
W: \PW Eng \PROJECTS\A- WT Projects \Water Comprehensive Plan - Sewer (91040101) \mpc Info Memo CIP Update 020813.doc
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CITY OF TUKWILA
CAPITAL IMPROVEMENTS PLAN
Table 7.2 Summary of Project Costs for Recommended Lift Station Projects
Project ID Recommended Year
Short Term
(2013 -2019)
Long Term
(2020 -2030)
—2013,
$250,000(1)
L -1 Long -term
$702,000
L -2 Long -term
$490,000(1)
L -3 Long -term
$490,000(1)
L -4 Long -term
$409,500
L -5 Long -term
$409,500
L -6 Long -term
$117,000
L -7 Long -term
$605,000(1)
L -8 Long -term
$117,000
L -9 Long -term
$4,400,000(1)
L -10 Annual
$70,000(1)
$110,000(1)
Total
$320,000
$7,850,000
Notes:
1. Cost estimates provided by City.
7.3.1.1 Replace and Expand Lift Station 2 (L -1)
It is projected that Lift Station 2 will experience a large increase in flow as this station will
convey flows from the new Drainage Basin 14 (via Lift Station 11) to the King County sewer
system. The City has observed no growth recently for the new area, and thus does not
anticipate a large increase in flows within the near -term timeframe.
Lift Station 2 has an on -site generator that has reached the end of its useful life and will need to
be replaced within the short -term timeframe. For the purposes of this CIP, it is anticipated that
Lift Station 2 will have to be replaced and expanded within the long -term timeframe.
7.3.1.2 Replace and Expand Lift Station 3 (L -2)
Flows to List Station 3 are projected to exceed the lift station capacity by the year 2030. The
City has observed minimal growth recently in the flow to Lift Station 3 and does not anticipate
that the station's capacity will be exceeded in the near -term. Lift Station 3 has a wet pit/dry pit
type of configuration and the lift station structure will reach its useful life in year 2022. Carollo
recommends that the City monitor the Lift Station 3 flows and replace this station with a
submersible lift station when the capacity is exceeded. For the purposes of this CIP, it is
anticipated that Lift Station 3 will need to be replaced and expanded within the long -term
timeframe.
7.3.1.3 Replace Lift Station 4 (L -3)
Based on the hydraulic capacity analysis, Lift Station 4 has adequate firm capacity for the year
2030 projected flows. However, the condition of the lift station is fair and may need to be
CAROLLO ENGINEERS 7 -4
pw. / /Carollo/ Documents /Clienh!WA /Tukwila /8472A00/Deliverabes /Chapter 7 /Ch07.docx
February 2013
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CITY OF TUKWILA
CAPITAL IMPROVEMENTS PLAN
replaced. Due to these condition concerns, it is recommended that this lift station be replaced
with a submersible station within the long -term timeframe.
7.3.1.4 Replace Lift Station 5 (L -4)
Lift Station 5 has adequate capacity for the predicted year 2030 flows. However, based a design
life of 20 years, the pumps will reach the end of their useful life in year 2022. In addition, this
station was built in 1975 with wet pit/dry pit configuration and the structure is anticipated to
reach the end of its useful life by the year 2025. The overall condition of this lift station was
rated as "fair" and thus it is recommended that this lift station be replaced within the long -term
timeframe with a submersible type lift station.
7.3.1.5 Replace Lift Station 6 (L -5)
Lift Station 6 has adequate capacity for the predicted year 2030 flows. However, based a design
life of 20 years the pumps will reach the end of their useful life in year 2019. In addition, this
station was built in 1975 with wet pit/dry pit configuration and the structure is anticipated to
reach the end of its useful life by the year 2025. The overall condition of this lift station was
rated as "fair" and thus it is recommended that this lift station be replaced within the long -term
timeframe with a submersible type lift station.
7.3.1.6 Replacement of Pumps at Lift Station 8 (L -6)
Lift Station 8 is a submersible stations built in 2007 and it is anticipated that the pumps will
reach the end of their useful life in the year 2027. Based on the capacity analysis, the station
has sufficient capacity to meet year 2030 predicted flows. Carollo recommends performing a
pump draw down test to confirm the pumps actual capacity and replacing the pumps when the
tests indicate that pump station firm capacity is less than is required. For this CIP, new pumps at
Lift Station 8 were assumed for the long -term timeframe.
7.3.1.7 Abandon Lift Station 9 (L -7)
Lift Station 9 has pumps that have already reached the end of their useful life, based on an
assumed 20 -year design life. In addition, the station has a wet pit/dry pit configuration and the
structure is anticipated to reach the end of its useful life in the year 2030.
The City wishes to eliminate this lift station and connect to the nearest King County sewer in
Interurban Ave South. For this CIP, costs for demolition of entire station and connecting to the
King County trunk line are included in the long -term timeframe.
7.3.1.8 Replacement of Pumps at Lift Station 10 (L -8)
Lift Station 10 is a submersible station, built in 2007 and it is anticipated that the pumps will
reach the end of their useful life in the year 2027. Based on the capacity analysis, the station
has sufficient capacity to meet year 2030 predicted flows. Carollo recommends performing a
pump draw down test to confirm the pumps actual capacity and replacing the pumps when the
tests indicate that pump station firm capacity is less than is required. For this CIP, new pumps at
Lift Stations 10 were assumed for the long -term timeframe.
CAROLLO ENGINEERS 7 -5
pwJ/ CarolloiDocuments /Client/WA/Tukwi!ai8472A00 /Deliverables /Chapter 7 /Ch07.docx
February 2013
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CITY OF TUKWILA
CAPITAL IMPROVEMENTS PLAN
7.3.1.9 Replace Lift Station 12 (L -9)
Lift Station 12 conveys flows from Drainage Basins 4 and 8 to the King County trunk. Similar to
Lift Stations 5, 6, and 9, Lift Station 12 also has sufficient capacity to convey the predicted year
2030 flows. The station was originally built in 1972 (wet pit/dry pit style) and pumps were
replaced in 2003. It is anticipated that both the pumps and structure reach their useful life by
year 2023.
The City is currently considering alternatives to serve Drainage Basin 4. Depending on the
City's decision, flows to Lift Station 12 may be significantly different than predicted. Therefore, it
is recommended that the City first monitor flows at the lift station and then replace it with
submersible style station when either the flow to the station exceeds the firm capacity of the
pumps or when the pumps and structure reach the end of their useful life. For this CIP, a new
Lift Station 12 was assumed for the long -term timeframe. Due to the size of this project, it is
anticipated that design will last one year and construction will last two years.
7.3.1.10 Replacement of Lift Station Generators (L -10)
As the generators at the lift stations age, they will need to be replaced. To fund this
replacement, the City is planning on establishing a generator replacement fund with an annual
contribution rate of $10,000.
7.3.2 Pipeline Projects
The City's sewer system will require several improvements to adequately provide service
through the planning period. Several pipes were identified as having reached the end of their
useful life or deficient due to sags. The following section presents a summary and estimated
project costs to replace or repair the deficiencies in the system. Additionally, the City currently
has a rigorous infiltration and inflow (Ill) reduction program and continued funding of this
program is recommended through the planning period. Figure 7.2 presents the location of the
pipelines CIP projects. A summary of pipeline project costs is presented in Table 7.3.
7.3.2.1 Annual Pipeline Repair Program (P -1)
The City has several sections of the conveyance system that are estimated to have reached the
end of their useful life. It is estimated that the annual pipeline repair program for the City's
sewers would cost approximately $1,490,000 per year. The City will evaluate which projects to
include in this program on a yearly basis.
CAROLLO ENGINEERS 7 -6
pw / /Carollo!Documents,'ClienL'WA /Tukwila /8472A00 /Deliverables /Chapter 7 /Ch07.docx
February 2013
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CITY OF TUKWILA CAPITAL PROJECT SUMMARY
2013 to 2018
PROJECT: Future Sewer Lift Station No. 13 Project No. 99740205
DESCRIPTION: Due to utility conflicts with existing utilities, a new sewer lift station will be required near 65th Ave S and
Southcenter Blvd. A gravity sewer main is not possible under 1 -405.
JUSTIFICATION: Existing line is undersized and has a severe sag. Increased development on the North Hill exacerbates
the deficiency.
STATUS: Design will be coordinated with WSDOT and Seattle Public Utilities.
MAINT. IMPACT: Less flushing maintenance to clear debris from sag and from the improved HOV manhole alignment.
COMMENT:
Other alternatives are being reviewed due to WSDOT requirements. Formerly known as Gravity Sewer
under 1 -405 to Tukwila Parkway.
FINANCIAL Through Estimated
in $000's
2011 2012 2013
2014
2015
2016
2017
2018
BEYOND TOTAL
EXPENSES
Design
80
278
358
Land(R/W)
0
Const. Mgmt.
139
139
278
Construction
927
928
1,855
TOTAL EXPENSES
80
0
0
278
1,066
1,067
0
0
0
2,491
FUND SOURCES
Awarded Grant
0
Bond /PWTF Loan
278
1,066
1,067
2,411
Mitigation Actual
0
Mitigation Expected
0
Utility Revenue
80
0
0
0
0
0
0
0
0
80
TOTAL SOURCES
80
0
0
278
1,066
1,067
0
0
0
2,491
2013 - 2018 Capital Improvement Program
121
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CITY OF TUKWILA CAPITAL PROJECT SUMMARY
2013 to 2018
PROJECT: Southcenter Blvd Sewer Upgrade Project No. 99840202
DESCRIPTION: Upgrade 3,200 LF of 8" to a larger capacity 12" system from Macadam Rd to the 1 -405 undercrossing
on Southcenter Blvd.
JUSTIFICATION: Flows have greatly increased with additional connections to the basin from the North Hill apartment
buildings causing the system to be deficient in terms of capacity for peak discharges.
STATUS:
MAINT. IMPACT: Improved service would reduce maintenance liability.
COMMENT: Coordinate with 1 -405 improvements to Southcenter Blvd and Future Lift Station No. 13.
FINANCIAL Through Estimated
in $000's
2011 2012 2013
2014
2015
2016
2017
2018
BEYOND TOTAL
EXPENSES
Design
180
180
Land (R/W)
0
Const. Mgmt.
90
90
180
Construction
600
600
1,200
TOTAL EXPENSES
0
0
0
180
690
690
0
0
0
1,560
FUND SOURCES
Awarded Grant
0
Bond /PWTF Loan
180
690
690
1,560
Mitigation Actual
0
Mitigation Expected
0
Utility Revenue
0
0
0
0
0
0
0
0
0
0
TOTAL SOURCES
0
0
0
180
690
690
0
0
0
1,560
2013 - 2018 Capital Improvement Program
122
8
CITY OF TUKWILA CAPITAL PROJECT SUMMARY
2013 to 2018
PROJECT: CBD Sanitary Sewer Rehabilitation Project No. 91140203
The asbestos concrete pipe in the CBD (commercial business district) is approximately 45 years old and
DESCRIPTION:
becoming soft. Slip lining the pipe will reinforce the strength with little impact to roadways and minimal excavation.
If the pipe collapses, the street will have to be excavated and the cost of the repairs will be significant. In the
JUSTIFICATION:
last five years we have had two major pipe failures on Andover Park West.
STATUS: A Public Works Trust Fund loan was successfully obtained in 2012 for construction.
MAINT. IMPACT: Reduced maintenance and repair costs.
COMMENT: The limits of the 2013 project is APW to APE from Minkler Blvd to 5 180th St.
FINANCIAL Through Estimated
(in $000's)
EXPENSES
Design
Lond(R8m)
Const. Mgmt.
Construction
TOTAL EXPENSES
FUND SOURCES
Awarded Grant
pmposedPVVTF
Mitigation Actual
Mitigation Expected
Utility Revenue
TOTAL SOURCES
2011 2012 2013
0
0
0
0
0
0
80
120
800
1,000
750
250
1,000
2014
0
0
0
2015
0
0
0
2016
0
0
0
2017
0
0
0
2018
80
120
800
1,000
750
250
1,000
BEYOND TOTAL
0
0
0
Project Location
2013-2018 Capita/Improvement Program
117
160
0
240
1,600
2,000
0
1,500
O
O
500
2,000
9