South Platte River Basin District 64 Diversion Structure Invent

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August 4, 2004 South Platte River Basin District 64 Diversion Structure Inventory 3 Schneider Ditch Narrative of Structure Components and Repair Plan The Schneider Ditch structure consists of a dam/spillway with five 3-foot-wide timber stoplog regulator gates, and a diversion consisting of two 5.5-foot-wide timber vertical lift headgates. The structure is located toward the east end of an island in the river, and spans between the island and the south bank of the river. There is also a dam from the island to the north bank of the river, which does not appear to be man-made. It is constructed of branches and has vegetation growing on it, possibly constructed by a beaver. The overall condition of the structure appears to be good. Recent improvements have been made to the dam, similar to those discovered at the South Platte and Pawnee structures. There is a 2-foot-thick by 4.5-foot-high concrete wall constructed across the upstream side of the original structure, which is connected to four original concrete piers now acting as counterforts. It appears that the piers were once taller, and have been purposely broken off to match the configuration of the low-level dam. The five regulator gates described above were constructed along the length of the dam. A horizontal crack was found through one of the counterforts, approximately 18-inches from the top. Minor hairline crack repair is needed. The downstream portion of the south endwall (abutment) is significantly undermined, and the void should be filled with pressure-injected grout. This wall should have been constructed without an angle toward the river, as it will constrict higher flows. Undermining has also occurred along the downstream side of the spillway apron and at the north endwall (abutment). The voids in these areas should be filled with pressure-injected grout. Erosion has occurred just downstream of the north and south endwalls, where downstream channel and bank stabilization is needed. Minor bank stabilization is needed upstream of the north endwall. Decking and handrail should be installed, providing better access from the south endwall, across the dam, to the north endwall. There are no lifting mechanisms for the two headgates of the diversion structure. The gates have to be operated manually, and a steel dowel placed through the timber to maintain their position. New gates with lifting mechanisms should be installed. Additional downstream channel stabilization and north bank stabilization is needed. Erosion has occurred behind the downstream end of the north wingwall. The cold joints between the headwall and the north and south wingwalls should be sealed with an epoxy grout. Dredging upstream of the structure is also needed. Summary of Recommended Repairs Dam/Spillway o Repair damaged and undermined concrete o Install downstream channel and bank stabilization o Install upstream bank stabilization (north bank) o Provide better access and install decking and handrail Diversion o Install new gates with lifting mechanisms o Install downstream channel and north bank stabilization o Seal cold joints between headwall and wingwalls Farnsworth Group