C150319 Feasibility Study - Laserfiche WebLink

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Project Description and Alternatives There are four separate projec ts to repair aging/failing infras tructure contemplated in this application (Figure 2). The projects are listed in order of importance to the continued efficient, reliable, and safe functioning of the ditch system. Project 1 – Repair of the Diversion Headgate. The existing radial gate in the diversion headworks is estimated to date from the early 1900’s. The lower quarter of the gate has been subject to corrosion, erosion by suspended sediment, and debr is impact over those years and has decayed to the point where failure may be imminent. Project 2 – Replacement of existing pipeline along Broadway. The ditch is conveyed in a 42-inch by 29-inch corrugated metal pipeline in the Broa dway right-of-way, generally between the Union Pacific Railroad right-of-way and north boundary of the Colorado Division of Wildlife. Presently, the pipe crown has fatigued and failed in a number of locations, allowing stormwater, sediment, and other debris to enter the pipeline. When t he pipeline was constructed, it was not installed with adequate cover over the top of the pipe. Du ring the intervening years, buses and cars have pulled onto the shoulder along Broadway and on-top-of or across this pipeline, weakening the pipe crown and resulting in its current condition. The pipeline, in its current condition, may also present a liability conc ern for the company. Project 3 – Provide a sand-out structure downstream of the Clear Creek diversion. The ditch company does not currently have an operable river retu rn in the upper segment of the ditch, other than an augmentation station. The purpose of this project would be to provide a means of flushing diverted sediment and other debris back to the river and out of the ditch system. This facility is an important maintenance reduction meas ure due to the volume of debris and sediment diverted, and the number of piped sections along the ditch. Project 4 – Pipe approximately 1500 feet of ditch upstream of Federal Boulevard. The Fisher ditch is an open, earthen ditch located at the bo ttom of a bluff upstream of Federal Boulevard. Over the years, the residents at the top of the bluff have dumped tremendous quantities of miscellaneous debris at the top of the bluff, including furniture, bui lding materials, yard waste, etc. Over time, this material slides into the ditc h at the bottom of the bluff, creating significant operational challenges and addi tional maintenance costs. A summary table of the alternatives fo r each project is provided in Table 4. Table 4: Alternative Summary Matrix rn Alte ative Project 1 Project 2 Project 3 Project 4 Notes Alternative 1 No Action $0 No Action $0 No Action $0 No Action $0 Anticipated to result in infrastructure failure and/or company liability Alternative 2 New gate, hoist and actuator $57,500 New 36-inch PE pipeline $127,680 Rehab. existing spillway $56,875 Fencing along top of slope $73,125 Alternative infeasible or more expensive than preferred alternative Alternative 3 Rehabilitate gate $14,950 New 38-inch X 24-inch RCPE pipeline $142,440 New sand-out, gates and outlet pipe $105,625 New 1500-foot 48-inch PE pipeline $242,125 Preferred alternatives address issues while providing most value to shareholders Alternative 1 Alternative 1 – No Action on any project . The No Action alternative would have potentially serious consequences to the ditch company, parti cularly in the cases of Projects 1 and 2. Continued neglect of the headworks diversion gat e will lead to failure, possibly preventing the ditch from being shut down during high water or some other critical time. This scenario could lead to overtopping and/or breaching of the ditch banks and flooding of urbanized areas located along and below the ditch, resulting in catastrophi c liability to the company and its shareholders. Project 2 is similarly critical to ditch operations a nd avoidance of liability. Further deterioration of 6