Pipelines & Tunnels
Fall Creek/White River Tunnel
The deep rock tunnel system to be used for storage of combined sewer overflows, included nine miles of 18-foot finished diameter, concrete lined tunnel, 20 drop shafts over 200 feet deep, and over 10,000 feet of consolidation sewers ranging in size from 24-inches to 108-inches. Because the VE study was conducted at 60% design, many design decisions had been made including all of the major variables with tunnel configuration. With a focus on the consolidation sewers and the drop structures, VE alternatives included reducing the length of the approach channels for the vortex drop structures based on experience from other projects. In several locations there were opportunities to extend cut and cover consolidation sewers to reduce the length of the substantially more expensive tunnel adits.
Pipeline and Flow Control Structure
The 5th phase of this 33-mile long pipeline system was to install approximately 3,000 feet of 60-inch welded steel pipe, along with a new flow control structure (FCS) to split the 120 cfs flow for delivery commitments to two other pipeline systems and to a nearby river for environmental commitments. The FCS will use two sleeve valves to dissipate up to 650 feet of head in the pipeline to atmospheric pressure for delivery to one of the other pipelines and the river. Additionally, an energy dissipater box will be constructed at the discharge into the river to dissipate the head from the top of the hill where the FCS is located to the river elevation. A plunger valve will be used to match the existing head in the second pipeline system. The VE Team was given permission to reconsider the planning level decisions resulting in a recommendation to relocate the FCS resulting in savings of over 20% of the construction cost with additional O&M savings.
Mountain Flow Pipeline
SVS recently completed a Value Engineering Study on a pipeline project consisting of construction of 2.2 miles of 84-inch welded steel pipeline along a major State highway through the mountains. To avoid disturbing potential slide areas adjacent to the highway, the pipeline is proposed to be constructed on the south side of the highway for the first 1.15 miles, then cross the highway and continue on the north side of the highway. The project includes installation of control valves near an existing flow control station. Primary issues involve the stability of adjacent slopes, high water table in some areas, coordination with future highway widening, and traffic control during construction. The owner accepted recommendations that will save almost $7.5 million and increase the water supplied to the users over the proposed design.
Mountain Tunnels, Inland Feeder
The study covered two contracts to build 10 miles of 14-foot diameter hard rock tunnels through the foothills mountains. The ground conditions are very difficult because of the fractured rock, hot ground water, and numerous fault crossings. The tunnels will be excavated with a tunnel boring machine. The lining is a combination of cast-in-place concrete and steel.
Kansas Hillside Interceptors
This $9 million stormwater interceptor project is part of a much larger flood control project near Kansas City, KS. There are three stormwater interceptors in this system. The Mission Road Interceptor uses 520 feet of 60-inch RCP and 1,135 feet of 78-inch RCP. The Cherokee Street Interceptor uses 1,863 feet of 72-inch RCP. The Rainbow Boulevard Interceptor uses 106 feet of 78-inch RCP and 763 feet of 96-inch RCP. These interceptors are designed to capture the 25-year stormwater runoff from a steep hillside that generates velocities approaching 22 fps. The alignments are through an urbanized area with numerous utility conflicts, roadway crossings, and railroad crossings.
This large canal project involves enlarging and enclosing the conveyance system to increase capacity and increase safety. The existing canal is a 21-mile long open canal with a 550 cfs diversion and approximately 350 cfs capacity at the end of the canal.
An objective of this Value Study was to provide input to assist the client in the decision making process between several design alternatives to enclose the canal system. To achieve this objective, the Value Team first looked to optimize the current alternative solutions using the value engineering methodology. In doing so, the Value Team came to realize that the function that must be accomplished for operational success was to reduce the lag time in flow changes from the diversion. The team developed a number of Value Alternatives that met this requirement while optimizing cost and operations of the enclosed system. Four optimum combinations were identified from which the Value Team offered a preferred solution that achieved the required reduction in the lag time for flow control at the lowest overall life cycle cost.
This Client wants to more fully develop their water rights and make safe, reliable and cost effective water deliveries to customer agencies while developing a financially successful water supply system.
The Client purchased significant water rights, including a pump station and a diversion structure, a raw water pipeline and easements, and several wells located on the property as part of their water rights portfolio. The Client conducted a thorough preliminary evaluation of these water rights, the future estimated water demands for potential customers, and the costs and infrastructure necessary to provide the water supply to the interested local customers. This preliminary evaluation reviewed several options before selecting a preferred alternative consisting of a pipeline that will convey treated surface water from the local Water Treatment Plant to a storage reservoir.
Under an ongoing VE contract, the Client requested that SVS conduct a Value Study with several objectives including: evaluating the strengths and weaknesses of the preferred alternative and make recommendations to the Client as it commences pre-design tasks and negotiation of water supply contracts for this alternative; evaluating the effectiveness and integration of the components of the recommended alternative to meet the Client’s business and water supply goals and identify alternative approaches to developing the most reliable and safe water supply system in a cost effective manner; and provide suggestions on pre-design tasks, controls, marketing approaches, and asset investigations and planning for the District to implement as it proceeds to develop the Water Project.
As a result of the Value Study, the Value Team recommended alternatives which resulted in over $5 million implemented savings while improving the Client’s bottom line and delivering the required water supply capacity. An additional $50 million in potential savings was still under consideration as of this writing.
This project is part of a more comprehensive urban flood control program for southeast Louisiana. The project consists of the installation of large cast-in-place covered box culverts, drainage pipes and enlarged water lines in the medians of the boulevards in the City of New Orleans. These areas are graced with historic homes, structures and ancient live oaks, all of which must be protected during the construction.
The value team recommended alternative materials and methods for constructing and supporting the box culverts and draining the streets. The value team also presented ideas in support of crossing under the streetcar tracks as well as alternatives to address protection of historic assets and traffic management during construction.