ENR MOUNTAIN STATES 2014 BEST PROJECTS AWARD Project Description The Southern Delivery System (SDS) is a regional Colorado project that will convey Arkansas River water stored in Pueblo Reservoir to Colorado Springs, the City of Fountain, Security Water District, and Pueblo West Metropolitan District. Phase 1 components include a reservoir connection at the North Outlet Works of Pueblo Dam, 50 miles of large-diameter water pipeline, three pump stations, and a 50 million-gallons-per-day water treatment plant and finished water pump station. The Pueblo Dam Connection (PDC) was constructed as two projects with two separate construction contractors; it was completed in June 2014. Together, the two projects form the connection that will bring source water from Pueblo Reservoir to the partner communities. The PDC is a 21st-century adaptation of Pueblo Dam, which was completed in the 1970s. PDC starts with a retrofitted connection to the existing flange on the 48-inch square outlet slide gate of the river outlet works inside Buttress No. 16 of Pueblo Dam. A stainless steel liner was installed into the existing concrete discharge tunnel that transitions to a 54-inch circular pipe section and increases to a 90- inch round pipe. The pipe bifurcates after exiting the outlet tunnel. The primary pipeline section to the new river outlet follows Buttress No. 16 to the new Fixed Cone Valve Facility (Valve Facility). The Valve Facility houses a 60-inch fixed cone valve and 60-inch rotary valve for isolation and can release 1,120 cubic feet per second of water. The secondary pipeline section is the 90-inch turnout to the SDS pipeline and consists of 1,600 linear feet of 90 inch–diameter, welded steel pipe. Along this pipeline is a vault that houses a 90-inch meter, two turnouts for a future hydropower plant, a 90-inch diameter tee for a future interconnection to the South Outlet Works, and a 36-inch diameter turnout for Pueblo West. Overcoming Challenges and Teamwork The fact that the PDC would become part of a federally-owned and managed asset set in motion extraordinary challenges that were overcome with technical knowledge and skill, as well as unprecedented collaboration and teamwork between federal and state agencies, county, city and metropolitan district governments, private companies, and the public. The

SDS team was responsible for design and construction of the improvements and worked closely with four U.S. Bureau of Reclamation (Reclamation) offices to develop the design criteria, review and accept the construction documents, provide oversight of construction, and oversee optimization of the facility. Federal ownership of the dam also necessitated stringent security measures, including rigorous background checks for numerous SDS team members and prior clearance for all SDS and contractor team members. Federally approved security guards also were stationed on site at all times. Periodic meetings, frequent phone calls, and documentation/sharing of protocols helped ensure the safety of Pueblo Dam and the SDS facilities. In addition to SDS, Colorado Parks and Wildlife and Pueblo West Metropolitan District had unrelated construction activities underway at Lake Pueblo State Park. All entities, including Pueblo County, closely collaborated to reduce conflict between projects, public confusion, and maintain access to nearby public recreation amenities. Monthly meetings with emergency first-responders also were facilitated by SDS to protect the safety of workers and the public.

The unparalleled teamwork and collaboration on SDS was observed and celebrated at two events: A 2011 community marking the start of construction of the PDC and an October 2013 “brick laying” event that acknowledged the many local businesses participating in construction. Pueblo brick manufacturer Summit Brick Company hosted and helped bring together construction

and community leaders to recognize the more than 300 companies and organizations in Colorado that have helped plan and construct SDS. Safety Program Description The SDS team conducted a pre-qualification process for contractors and then performed a best-value selection process. Each proposal included the contractors’ safety manual, requirements on the corporate safety culture, and specific safety practices unique to the project. In addition to the contractors’ site-specific safety plans, the contractors were also required to adhere to Reclamation’s health and safety standards and inspection, as well as two specialty safety plans. To minimize risk associated with stored energy at the dam, barges were used prior to construction to set the bulkhead gate upstream of the North Outlet Works. Divers assisted in installation and inspection of the upstream gate. A Dive Plan was

implemented that addressed boat and diving safety and included stringent lockout/tag procedures, decompression chambers, back-up air supplies, bail-out bottles, and redundant communication. The second specialty safety plan was implemented to install a cofferdam in the channel for excavation to the bottom of the dam (approximately 85 feet below the top of the river outlet). The Dewatering Plan was developed to keep workers and equipment safe during excavation. The plan entailed limited worker exposure in the excavation area, the use of personal protective equipment such as harnesses and personal life preservers, protocols for multiple egress options, a spotter for crane operations and excavation work, multi-mode audible and visual communication signaling, stringent lockout/tag-out procedures, and management of groundwater infiltration. To complement these safety procedures, regular meetings and training exercises were held with the contractors, dam operators, park ranger staff, and local emergency medical services, police, fire, and heavy rescue to prepare for unforeseen events. This collaboration laid the foundation for teamwork needed to coordinate potential emergencies in a challenging, multi-jurisdictional environment. With all of these unique safety risks and procedures, the contractors completed 102,511 hours of work without a lost-time or recordable safety incident. Innovation & Contribution to the Industry/Community

Design of the PDC as a retrofit to a 1970s-era dam was innovative by definition, for it is one of the only square-gate-to-round-pipe adaptations completed. The joint decision to modify an existing river outlet on the north side of Pueblo Dam to enable the SDS connection and enhance operational releases to the Arkansas River is a noteworthy contribution to southern Colorado communities. The adapted connection will not only bring a reliable water source to a growing population of

nearly 500,000 people; it can be mimicked on other similar projects that maximize the functionality of existing dams. Building the North Outlet Works also facilitates a future connection between the south and north outlet works to provide operational redundancy. Moreover, the new outlet works includes provisions for future hydropower development. Other innovations include the use of a high-definition scanner to survey the shape of the connection point inside Pueblo Dam so the pipe supplier could manufacture the liner, as well as to ensure accuracy of the steel tunnel liner on which the PDC is based. A rail and trolley were used to transport the pieces of pipe manufactured off-site for reassembly and

installation inside the dam. Another innovation was computational fluid dynamic (CFD) modeling to change Pueblo Dam from a regulating spillway to a controlled discharge through the Valve Facility. It also provides a turn-out for the SDS pipeline and other future water needs. The CFD model resulted in design that would minimize cavitation under high discharge conditions and locate the air vacuum valves. A contribution to the industry was the use of a multi-product, multi-coat system that was developed and applied in the carbon steel pipeline and valves to protect the facility from invasive species (i.e., mussels). Piping for chemical injection also was installed in the 90-inch vault for further protection. Construction Quality & Craftsmanship Constructing the PDC as a retrofit to an existing federal dam proved to be a significant technical challenge. Original design documents required the use of a submergible vehicle, underwater excavation, and placement of tremie concrete. As part of its strategic procurement process, the SDS team encouraged responding contractors to offer suggestions on how to enhance project quality and safety and cost saving ideas. The successful contractor suggested dewatering the river channel and excavating to the dam’s foundation, then use a traditional concrete placement method to build up to the new Valve Facility. The proposal resulted in upfront costsavings, removed the risk of a submergible vehicle, and delivered a higher-quality product. In addition, the proposed schedule and work sequence mitigated site risks, including impacts to an adjacent pump station, reduced groundwater and hydrostatic pressure impacts, and provided a favorable revegetation schedule. Part of the challenge of retrofitting the PDC into an existing dam was locating a company that could build a customized connection within schedule. The technical challenge was to adapt a 48-inch, square, 1970’s slide gate to a round pipeline that would taper up to 90-inches in diameter. The stainless steel, square-to-round adapter ultimately was manufactured 50 miles away by Springs Fabrication, Inc. In addition to the contractors’ suggestions and weekly quality control reports, the SDS team chose a number of specialized, independent firms that provided quality assurance inspection services, including:

Certified Weld Inspection

Geotechnical Materials Testing

NACE-Certified Corrosion Protection

Noise and Dust Background Levels and Monitoring

Seismic Monitoring of Construction Vibration

Pre-construction Photography and Videotaping The PDC was completed on time and on budget through contractor innovation and quality control, as well as the SDS team’s quality assurance efforts. Function and Aesthetic Quality of the Design Design of the PDC allows Reclamation much greater range of releases to the Arkansas River, benefitting many parties. One example is the State Hatchery, which needs lower flows to operate continuously. Previously, when low flows could not be maintained, the hatchery was cut off. To help the North Outlet Works blend into the dam and river environment as much as possible, a small area of the river bed was dewatered and excavated to a depth of 85 feet, allowing the placement of a concrete foundation below-grade. Dewatering was accomplished after erection of a cofferdam and relocation of about 200 fish by the Division of Wildlife and a private contractor using scientifically sound and fish-safe methods. The fish habitat also was supplemented with the placement of several large boulders unearthed during trench excavation. Parks and Wildlife staff worked with the contractor and SDS team members to place boulders along riverbanks that would potentially become inundated, as well as in several locations above the waterline for aesthetic purposes. Relocating the boulders saved the State of Colorado money and also diversified the fish habitat. Restoring vegetation to the former construction area was also important. The SDS team created a process during pipeline construction that was used for the PDC post-construction area. The process included university-based botanical experts selecting native seed mixes and the installation and use of irrigation systems. Irrigation systems are generally not used in pipeline construction, but have proven successful with SDS, despite drought conditions.