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I I I I I I I I I I I Information is provided in Appendix G on the cut-throat flume including the discharge tables. The information provided is from Colorado State Experiment Station Technical Bulletin 120. h is our intent [0 minimize the types of measuring devices and we believe an 8.inch flume will allow measurement of flows from all but two or three of the headgatcs. As can be seen in Appendix G, the discharge capaciry varies from 2.97 cfs at 1.0 fOOl of head [Q 10.63 cfs at 2.0 feet of head. Based on information supplied by the ditch company the discharge at most of !.he turnouts ranges from 1 cfs 10 3 cfs. One rumaut requires about 12 cfs and there arc three [Q four turnouts that discharge approximately 4 cfs [Q 5 cfs. Structure 58 - Meter Gate. The headgates that supply the cemer-pivQ[ sprinklers will be measured using a meter gate as shown on Figure 11. This gate is a standard cast.iron gate that can be obtained from suppliers with the metering vaults shown on Figure II. The gates can be supplied with various types of backs to attached lO plastic pipe, CMP. or flat back lO boil to a concrete headwall. These gates are relatively inexpensive, easy lO install. and have been laboralOry tested and calibrated with and the flow capacity chans provided by the manufacturer. At the present time there is no measuremem of flows to most of the cemer-pivOl systems. The meter gate wil1 allow measuremem of the discharge without changing the pumping system as the meter installs at the headgate. Sedimentation Sedimem carried in irrigation canals is generally composed of sands, sills, and clays. The clay sizes are carried in suspension through the full depth of water. Silt sizes are either suspended in the water or are in the material moving along and close to the bed. Sand sizes move primarily along the bed. with brief periods of suspension in the water column. Continuously.suspended material is referred to as the wash load. Material which moves primarily in comact with the bed is referred lO as the bed material load. The wash load is generally beneficial lO irrigation operations. It increases opacity of the water, which inhibits algae growth. It helps to retard ditch leakage by forming a barrier of fine material on the ditch margins. In the fields, it tends lO retard percolation, especially at the upper end of a field. thus advancing water down l.he field faster and limiting unavoidable excess application depths at the upper end. The load of bed material is a mixed blessing, however. Some of that load is essemial for physical stability of canals. since water deprived of sediment is usually erosive. However, the be material load creates problems when it accumulates in conveyance systems. then requires periodic mechanical cleaning. A wide array of methods to beneficially manage sedimem in irrigation canals is available. The amoum of sediment taken into the main canal can be controlled at the headworks by a Owl Creek Feasibility Page I";