Site work for a water / sewer project in Denver, Colorado. Completed plans call for site work for a water / sewer project.

The Colorado Department of Natural Resources (DNR), on behalf of the Division of Parks and Wildlife (Colorado Parks and Wildlife; CPW) is soliciting Letters of Interest (LOI) from qualified Contractors interested in providing Construction Manager/General Contractor (CM/GC) services for a dam rehabilitation construction project (Project) at Tarryall Dam (Dam). The Dam is located along Tarryall Creek in Park County, Colorado, approximately 15 miles southeast of the town of Jefferson, Colorado along CO Highway 285, within the Tarryall Reservoir State Wildlife Area (SWA). The dam is owned and operated by CPW for recreational purposes and is a popular location to fish, boat, camp, and hike for the public. Background Tarryall Dam (DAMID: 230208, impounds Tarryall Reservoir) was completed in 1929 as a concrete arch dam with a concrete gravity thrust block at the right abutment, a service spillway left of the dam, and a low level outlet works (outlet works) near the maximum section. The Dam is rated as a "high hazard" dam with an extreme hydrologic hazard in accordance with the State Engineers' Office (SEO) regulations, indicating that "...loss of human life is expected to result from failure of the dam". Tarryall reservoir has an estimated normal operating capacity of approximately 1,000 acre-ft at the service spillway crest elevation of 8,863 ft and a maximum estimated capacity of 1,580 acre-ft at the dam crest elevation of 8,870 ft. The dam crest is 263 ft long and 6 ft wide and acts as the emergency overtopping spillway. The 70-ft high arch section of the dam is a cantilever gravity section with a horizontal construction joint and three vertical contraction joints. The left side of the arch ties into an exposed rock formation that makes up the left abutment. The right approximately 68 ft of the dam is a concrete gravity thrust block that ties into rock on the right abutment. Nearly 8-ft high parapet walls were installed at both abutments in 1977 that channel overtopping flows toward the middle of the dam with the intent of protecting the rock abutments. The dam crest between the parapet walls is approximately 150 ft long. Post-tensioned anchors were installed in the gravity thrust block at the right abutment in 2003 with the intention of increasing stability and reducing seepage through the joints in the thrust block. The service spillway is located approximately 200 feet to the north (farther left) of the left abutment arch contact. It is an uncontrolled 60-ft wide rectangular channel cut through the left abutment rock and the control section is approximately 7 ft below the crest of the dam (not considering the parapet walls). The outlet works consist of two 42-in cast iron conduits that are controlled with two cast iron vertical slide gates located on the upstream face of the concrete arch section that are manually operated. A dam safety Engineer's Inspection Report was completed in June 2021 that summarized the following concerns with the dam: * Damage to the upstream contraction joint near the outlet works and strip seal at the arch/gravity interface that does not provide a proper seal * Crest of the dam is not well graded, causing standing water and ice that creates minor spalling issues on the dam crest and exposure of the keyed joints * Spalling and freeze/thaw damage to the contraction joint right of the outlet works on the downstream face and a horizontal crack in the gravity buttress section * Seepage through horizontal crack in gravity buttress and left rock abutment * Historical seepage through contraction joints and arch/gravity interface joint * Activation of emergency overtopping spillway introduces reasonable risk of abutment rock plucking, downstream toe erosion and material removal, and potential dam failure Tarryall Reservoir is currently operating at a restricted reservoir level of 8,864 ft (gage height 32), which is approximately 1-ft above the service spillway crest and 6 ft below the dam crest. The operational restriction was agreed upon during 2015 when the dam was close to overtopping during a high runoff period. The restriction was primarily implemented due to the reasonable risk of damage to the rock abutments and downstream toe material if the dam was to overtop. Seepage through the contraction joints and the arch/gravity interface was also observed during the high runoff period in 2015. Project Objective Planned construction efforts will remedy the above described deficiencies in order to return the Dam to safe operating conditions. CPW is currently developing the project's 30% design, which may include the following: * Left Abutment Training Wall and Parapet wall construction * Erosion Control Structure downstream of the Arch and Gravity Section * Above-grade Joint Rehabilitation and Leakage Control * Installation of monitoring instrumentation. Construction is estimated to be a multi-million dollar endeavor depending on the final design selections and other construction related factors (including: availability of source material, foundation conditions encountered, and number of construction seasons required, etc). More details and better estimates will become available after the 30% design. A 30% Design submission is anticipated to be included with the forthcoming RFP. CPW's Consultant is anticipated to be nearing 60% design completion by the time the selected Contractor has a fully executed contract. Project Delivery Approach and Anticipated Project Challenges CPW has determined that this Project is best-suited to a CM/GC Alternative Delivery Method, in part, due to its high-altitude, remote location, confined site layout, harsh weather, and short construction season. Given the aforementioned Project considerations, predicted challenges at this time include: a short construction season, complex construction phasing, construction access, steep grades, and remoteness of the Project's site. The CM/GC Alternative Delivery Method will be beneficial to the success of the Project in that it will allow for early contractor involvement; positive Construction Manager (CM) Contractor input during the Project's design phase will be valuable in achieving an ideal balance between cost and construction efficiency, while minimizing the impacts to the SWA and CPW property. The Project's Integrated Project Team (IPT) will consist of: CPW's Capital Development Program Manager and staff; the Owner's Design Engineer Consultant (Consultant); the Owner's CM/GC Contractor (Contractor); and the Independent Cost Estimator (ICE). CPW has executed or will execute separate contracts directly with the Consultant, Contractor, and ICE. At such time that the Contractor is incorporated into the IPT, the Consultant is anticipated to be nearing 60% design completion. It is both expected, and imperative to the success of the Project, that all members of the IPT consistently conduct themselves in a professional and collaborative manner. General Role and Responsibilities of the Contractor It is expected that the qualified Contractor will contribute, at a minimum, the following early contractor expertise during the Project's design phase: * Safety and Security * Site Access, Layout and Development * Construction Methods, Sequencing, Schedule and Cost * Best Management Practices specific to embankment dam construction at high altitude * Interaction with Involved Agencies / Key Stakeholders / Local Community CPW requests that respondents are well-experienced in concrete arch dam construction and rehabilitation, and have a proven track record of safety and professional execution utilizing teamwork and innovative methods pertinent to the aforementioned Project challenges. CPW will send a Request for Proposals (RFP) solely to those companies or teams who submit a Letter of Interest (LOI) (additional details below). Issuance of an RFP is anticipated to occur the week of May 9, 2023, and will include conceptual designs and additional pertinent information for proposal development. Prime Contractors interested in an informal Project briefing with CPW should submit an LOI for the Project, including a request for the briefing. Project briefings are not required for submitting a Proposal, but will not be provided after issuance of the RFP. LOI Requirements LOIs are required to be submitted via Google Form, and must be received no later than May 5, 2023 at 5:00 PM LOI submissions will be used to compile a list of interested firms to receive any notices and announcements related to the Project. Contact For additional information or questions on the Project, contact Lincoln Harberger, P.E. (CPW Dam Safety Engineer/Project Manager) at Lincoln.harberger@state.co.us. The contact after release of the RFP will be Jeanette Barrow, DNR Contract Administrator, at jeanette.barrow@state.co.us.