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<br />CHAPTER FIVE <br />PLAN OF DEVELOPMENT <br /> <br />EXISTING STRUCTURE <br />The existing structure was built in the 1880's entirely of wood. The <br />structure is basically a wooden floor in the river which holds up a series <br />of flash boards which divert portions of South Platte River's flow into a <br />smaller side river channel. These diverted flows are then diverted into the <br />main canal by a new, smaller diversion dam. <br />The main diversion dam is in very poor condition. The structure itself <br />is rotten and the foundation has for the most part washed away. Operating <br />the flash boards is extremely dangerous and difficult due to the poor condition <br />of the structure. <br />GEOLOGY <br />The project site soils consist of the Aquolls-Aquents-Bandard units. <br />These units are excessively drained sandy loams formed in alluvium. This soil <br />tends to erode easily and as such will require special considerations in found- <br />ation design. The engineering Unified classification is SP-SM which is a <br />sandy gravel with some fines. This soil extends to a depth of 60 feet. <br />PROPOSED PLAN <br />The proposed structure will be of the same concept as the existing; it <br />will use flash boards to divert the water into the river side channel for <br />diversion into the main canal. The structure will be of reinforced concrete <br />with stop log supports and a 3 foot deep energy dissipating basin. The structure <br />will have concrete side and wing walls 10 feet tall to prevent the river from <br />eroding around the structure. The foundation will be a steel sheet piling <br />curtain which will also serve as a cutoff to prevent piping under the structure., <br /> <br />-16- <br />