Rio Grande - Manassa Conejos River & N Branch Stabilization_Water Activity Summary

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Water Supply Reserve Account - Grant and Loan Program Water Activity Summary Sheet Applicant: Manassa Land Irrigation Company Water Activity Name: Conejos River & North Branch Diversion and Stabilization Project Amount Requested: $383,700 Source of Funds: $50,000 (Rio Grande Basin Account) and $333,700 (Statewide Account) Matching Funds: $98,000 Water Activity Purpose: Structural or non-structural water project or activity County: Conejos Drainage Basin: Rio Grande Water Source: Conejos River Staff Recommendation Staff recommends approval of up to $50,000 from the Rio Grande Basin Account and $333,700 from the Statewide Account to help complete the Conejos River & North Branch Diversion and Stabilization Project project contingent on resolution of the items in the issues/additional needs section. Water Activity Summary: The Conejos River is a tributary to the upper Rio Grande River, accounting for nearly 40% of Colorado's Rio Grande Compact obligation. At the point that the river crosses state highway 285, 1-1/4 miles north of Antonito, there is a bifurcation, with a concrete diversion structure (locally known as "the Core") and a headgate system (Diversion Gates). The Core is almost 100 years old, and is in need of reconstruction. It was designed to split and balance the flow of the river into the main channel and the North Branch of the Conejos. Proper operation of the Core is therefore instrumental to both channels of the river. The Diversion Gates consist of five eight-foot wheel-and-stem headgates which are manually operated and accessed by a perilous 18 inch plank catwalk over the river. This structure is also unsafe and in need of replacement. Both the Core and the Diversion Gates require weekly and sometimes daily maintenance due to floating debris, log jams, high sediment load, bank erosion, and streambank instability. The effects of this problem include operational difficulty in meeting irrigation needs; poor water quality due to bank instability and resulting high sediment load; negative impacts on the condition of fisheries downstream of the diversion; lack of control and frequent documented losses of Compact waters during high flows; and the very real threat of flooding for communities north of the Conejos. If water were to breach the north bank of the main channel of the Conejos, the river channel would change course, bypassing the gaging station at Los Sauces, seriously impacting all water users downstream on both channels, and flooding the agricultural communities of Conejos County and the town of Manassa. There are 42 ditch companies on the main and north channels of the Conejos. Twelve of these ditch companies rely upon the North Branch diversion to irrigate a total of 22,204 acres, with excess flows returning to the main channel east of Manassa where they contribute to fulfilling Colorado's Rio Grande Compact obligation. Manassa Land Irrigation Company requests funds to address and remedy the issues associated with the North Branch diversion of the Conejos River, re-shaping the channel, stabilizing the streambank, replacing the Core and the Diversion Gates, and enhancing riparian areas at this bifurcation point. This Project will restore full operational capacity to both bifurcation structures, meet multiple consumptive and nonconsumptive needs in