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I I I I I I I I I I I I I I I I I I I Chapter V - PLAN OF DEVELOPMENT A. New Cache La Poudre Diversion A.I. PHYSICAL PLAN 1. General. The Greeley No.2 diversion structure was originally constructed around 1900 for the purpose of diverting agricultural irrigation water. The structure is located on the Poudre River approximately 1.5 miles south of Harmony Road and 3/4 mile east of Interstate 25. Access to the structure is through an access road located on the farm east of the diversion. Existing design drawings for the structure do no exist and; therefore, determination of its structural integrity was based solely on visual inspections. The structure is located along a section of river characterized by a meandering streambed located in a wide floodplain. The structure is located adjacent to a relatively high bank on the east and a low floodplain on the west. Details of the existing structure are shown on Figure V-I. The structure has a I5-foot-wide sand gate, which is used to control flows downstream of the structure and reduce sediment loads into the canal. The State Engineer's Office uses the structure as a control point for flows downstream of the structure. The diversion structure crest consists of four (4) radial gates 20 feet long and 4 feet high. There is also approxi- mately 70 feet of stop logs along the crest of the diversion structure. Water passes under the gate or over the stop logs where it drops approximately two feet (2') onto a concrete apron. The length of the apron varies, and no energy dissipation blocks exist. No downstream erosion protection exists other than the concrete apron and the natural cobbles present in the river. 2. Problem Areas. There are several problems which contribute to the need to rehabilitate or replace the structure. Following is a general list of deficiencies: 1. Spalling and deterioration of the concrete in the walls, slabs, and foundation. 2. Corrosion of gates which causes operational problems. 3. Trash accumulation in the gate openings during high flows. 4. Seepage under the foundation of the structure. 5. Deterioration of the stilling basin downstream of structure. 6. Inadequate to non-existent erosion protection. 7. Poor bond between the recent concrete slab overlays of the concrete base slab. 8. Erosion of the joint between the piers and the concrete base slab. The structure is believed to be near the end of its useful life span without repair of the deficiencies noted above. The concrete appears to be at a point where it is deteriorating PAGEI-OIIprerV