STATEMENT OF ISSUE
During and immediately following Tropical Storm Fay, a 36-inch diameter sewage force main under Capital Circle NE ruptured three successive times over a period of four days. After the third break the pipeline was taken out of service. The previously decommissioned Lake Bradford Road (LBR) Treatment Plant had to be reactivated to help manage the bypassed flow. Reconstruction of the LBR plant is a component of the City’s Advanced Wastewater Treatment Project. Putting LBR back into service has delayed the reconstruction and required that the City apply for a permit modification for a time extension for LBR reconstruction. Concurrent with restarting LBR, MWH-Engineering was retained to do an analysis to determine the cause of the pipeline failure. Data limitations prevented a conclusive determination, however, it is suspected that transient pressure waves resulting from pump fluctuations associated with power outages and generator fluctuation occurring during Tropical Storm Fay were the likely cause. Subsequent to the engineering analysis, a pressure test was attempted to explore the potential for salvaging the existing pipeline. Leakage appeared at a fourth location with only minimal pressure on the pipeline. Based on the above circumstances, staff believes the City must construct replacement pipeline capacity. This needs to be done in an expedited manner because the remaining capacity in the sewer system will not be sufficient in a major storm. Also, there are only 18 months left in the time extension requested by the City for operation of the LBR plant. This is a health-safety issue as well as a regulatory issue under the regulations of the Florida DEP and the USEPA. This agenda item requests a $4 million supplemental appropriation and emergency authorization for the City Manager to directly negotiate and execute one or more contracts to secure the design and construction of replacement pipeline capacity for the 36-inch force main damaged by Tropical Storm Fay.
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RECOMMENDED ACTION
Option 1: Authorize the City Manager to directly negotiate and execute with concurrence from the City Attorney on an emergency basis, one or more contracts to secure the design and construction of pipeline capacity to fully or partially restore capacity lost in the 36-inch force main damaged by Tropical Storm Fay. Appropriate $4 million for the project from the Sewer Fund - Series 2007 CUS Bond Fund Undesignated Balance.
FISCAL IMPACT
Option 1: Preliminary cost estimates for restoring conveyance capacity range from $3.9 million for partial capacity to as high as $6.6 million for full capacity restoration. At this time, funding of $4 million is requested from the Sewer Fund’s Series 2007 CUS Bond Funds Undesignated Balance. After a design is completed, should estimates indicate additional funding is required, staff will return to the Commission. It is possible that part of the expense of this project will be eligible for funding by FEMA, or the Federal Stimulus Package; however, that is not a certainty.
Mike Tadros, General Manager, Underground Utilities
Anita Favors Thompson, City Manager
For information, please contact: John Buss, Manager-Water Resources Engineering, Ext 6852
SUPPLEMENTAL MATERIAL/ISSUE ANALYSIS
HISTORY/FACTS & ISSUES
1. During and immediately following Tropical Storm Fay, a 36-inch diameter sewage force main under Capital Circle NE ruptured three successive times over a period of four days. After the third break the pipeline was taken out of service. The previously decommissioned Lake Bradford Road (LBR) Treatment Plant had to be reactivated to help manage the bypassed flow. Reconstruction of the LBR plant is a component of the City’s Advanced Wastewater Treatment Project. Putting LBR back into service has delayed the reconstruction and required that the City apply for a permit modification for a time extension for LBR reconstruction.
2. Concurrent with the restarting of the LBR treatment plant, MWH-Engineering was retained to do an analysis to determine the cause of the pipeline failure. This is the engineering division of MWH-Constructors, which is the contractor for the LBR project. Data limitations prevented a conclusive determination, however, it is suspected that transient pressure waves resulting from pump fluctuations associated with power outages and generator fluctuation occurring during Tropical Storm Fay were the likely cause.
3. Subsequent to the engineering analysis, a pressure test was attempted to explore the potential for salvaging the existing pipeline. Leakage appeared at a fourth location with only minimal pressure on the pipeline. Based on the above circumstances, staff believes the City must construct replacement pipeline capacity. It is believed that putting the existing pipeline back into service would result in further breaks either immediately or within the near future. Additional breaks would further disrupt the City’s transportation network and threaten the public health.
4. Replacement force main capacity needs to be constructed as rapidly as possible. There are only 18 months left in the permit time extension requested by the City for operation of the LBR plant. Also, although placing the LBR plant back into service has partially alleviated the capacity problem, the system still does not have capacity for major wet weather flows. Should a significant rainfall event strike Tallahassee, large volumes of untreated sewage will overflow and eventually enter into area water bodies in both the northeast and south-southwest parts of the community. In summary, this current circumstance is a health-safety issue for the community as well as a regulatory issue under the regulations of the Florida DEP and the USEPA.
5. Because the existing pipeline is under Capital Circle NE, replacing it through direct burial would be expensive and extremely disruptive to traffic. For this reason, consideration must be given to alternative construction methods that are less disruptive.
a. One such alternative method would be to use an alternative alignment outside of Capital Circle NE. Unfortunately, a new alignment would require acquisition of new right-of-way, and this would be costly and time consuming. Given the urgency of the need for replacement conveyance capacity, this alternative is problematic unless some partial capacity can first be restored.
b. One method of restoring partial capacity fairly quickly would be to insert a liner pipe into the existing pipe. This is referred to as sliplining. It has the advantage of not requiring right-of-way and because much less direct excavation is required, this method can be constructed with less disruption to traffic. There are disadvantages also, and one of them is that the slipliner must be smaller than the pipe it is inserted into and therefore it will have significantly less capacity. To address this lost capacity, a second smaller pipeline could be constructed by direct burial along the alternative alignment. Because the slipliner would be done first and would already be in service, the longer time required to acquire right-of-way for the parallel pipe would not be so consequential.
c. Another construction method that uses the existing alignment and which could potentially also avoid the lost capacity problem is a practice referred to as pipe bursting. With this method, a steel mandrel that is larger in diameter than the existing pipe, is hydraulically forced along inside the existing pipe. This bursts the pipe, expanding it outward and leaving a wider opening or tunnel through which a larger diameter liner pipe can be pulled.
6. Due to the urgency of need and the above described construction complexities, staff believes the most expeditious approach to restoring pipeline capacity will be to utilize a form of the design-build approach. The design-build approach is desirable because it facilitates communication between the constructors and designers during the design phase, which improves constructability of the design. Such communication is not possible under the City’s typical project approach where the design is entirely complete before the constructors ever see it at the bidding phase. The input from the constructors is particularly useful when evaluating alternative construction approaches such as with the current pipeline situation. An additional advantage of design-build is that it allows long lead-time materials to be ordered before the design is completed. Valves for a 36-inch pipeline can take up to nine months to be delivered.
7. A drawback of design-build is that it is difficult to estimate and agree on a construction cost for a design that has not yet been prepared. For this reason, modified forms of design-build have evolved. These include design-construction management and construction management-at-risk. These forms have most of the advantages of design-build and yet they overcome the construction cost issue by typically utilizing bidding by the construction manager of the various construction elements. This helps to assure the owner of a competitive price.
8. Construction manager-at-risk is currently being used for much of the work to be done on the City’s Advanced Wastewater Treatment project. To accelerate the pipeline project, staff would like to attempt to negotiate a design and construction management contract with MWH-Constructors, the construction manager for the LBR upgrade project. MWH has substantial experience with pipeline restoration and with sliplining projects. Additionally, MWH’s engineering division, MWH-Americas, conducted the failure analysis on the pipeline following T.S Fay and is already familiar with the pipeline details and the project constraints. If a satisfactory contract cannot be reached with MWH within a reasonable time period, staff will cease discussions with MWH and attempt to secure a contract with another construction management firm with design capabilities.
9. Due to the urgent need to restore pipeline capacity, it is not recommended that the City delay initiating this project to await a final eligibility decision from FEMA. FEMA’s pace for making decisions is simply not compatible with the community’s health-safety issue associated with potential sewage overflows nor with the City’s regulatory concerns under the regulations of the Florida DEP and the USEPA. Further, it should be recognized that project aide from FEMA typically comes with complicated, and time consuming, procedural requirements involving multiple reviews and approvals by various agencies. Although staff believes the City has no choice but to move forward with the pipeline project implementation, doing so outside of FEMA’s process may later complicate project eligibility.
CHARITABLE CONTRIBUTIONS
The contractor is being selected under emergency provisions to accelerate the pipeline project. Charitable contributions are not a factor.
OPTIONS
Option 1: Authorize the City Manager to directly negotiate and execute with concurrence from the City Attorney on an emergency basis, one or more contracts to secure the design and construction of pipeline capacity to fully or partially restore capacity lost in the 36-inch force main damaged by Tropical Storm Fay. Appropriate $4 million for the project from the Sewer Fund - Series 2007 CUS Bond Fund Undesignated Balance.
Option 2: Direct staff to execute the pipeline project as a conventional project by contracting for a completed design, which is subsequently let for competitive bids and subsequent award of a separate construction contract, all in compliance with the provisions of the City’s procurement policies. Appropriate $4 million for the project from the Sewer Fund - Series 2007 CUS Bond Fund Undesignated Balance.
Option 3: Provide other direction to staff.
FISCAL IMPACT
Option 1: Preliminary cost estimates for restoring conveyance capacity range from $3.9 million for partial capacity to as high as $6.6 million for full capacity restoration. At this time, funding of $4 million is requested from the Sewer Fund’s Series 2007 CUS Bond Funds Undesignated Balance. After a design is completed, should estimates indicate additional funding is required, staff will return to the Commission. It is possible that part of the expense of this project will be eligible for funding by FEMA, or the Federal Stimulus Package; however, that is not a certainty.
Option 2: Costs are anticipated to be similar to Option 1 since both options include some level of competitive bidding. The advantage of Option 1 is accelerated implementation. Due to the urgency of need for pipeline capacity, Option 2 is not recommended because it is the slower method of implementation.
Option 3: Unquantifiable at this time.
ATTACHMENTS/REFERENCES
None.