Changes are coming to the Paonia Reservoir. The Bureau of Reclamation (BOR), Fire Mountain Canal Company, and North Fork Water Conservancy District (NFWCD) will host a meeting at Memorial Hall in Hotchkiss on August 15 at 7pm, to explain the work that needs to be accomplished at the Paonia Reservoir this fall. The meeting will also outline the drawdown schedule and procedures for the reservoir so that work can begin in mid-September. This drawdown is designed to drain all water from the reservoir, which will expose the outlet structure and thereby increase sediment flushed into the North Fork.
Constructed in 1962, Paonia Reservoir supplies agricultural water to the North Fork Valley by capturing and storing spring runoff and snow melt. Paonia Dam releases stored water into the North Fork of the Gunnison River where 12 diversions transfer water through hundreds of miles of pipes and ditches to orchards, pastures, and organic farms across the valley. Unfortunately, the intake structure for the dam outlet has sustained significant damage over time and needs to be repaired to allow the dam to function properly. Additionally, the tributary to Paonia Reservoir (Muddy Creek) has deposited enough sediment over time to fill the reservoir to the top of the intake structure and render its additional water storage capacity to be null.
In the fall of 2016, the BOR completed an Environmental Analysis on the Paonia Dam Intake Structure Repair. The report reviewed the many options, ecological impacts, and public comments surrounding the drawdown of the reservoir and the process of repairing the damaged bulkhead.
The most critical concern to watershed health with this upcoming project is the potential impact to fauna and fisheries from the release of excessive sediment downstream into the North Fork of the Gunnison during the fall season when the river experiences it’s lowest flows. Significant amounts of sediment are expected to persist within muddy creek just below the dam to the confluence of Anthracite creek. Increased turbidity is likely to persist as far down as Hotchkiss through the construction window ending in November 2017. Sediment deposits will remain within the river channel until flows are high enough to move them downstream in the spring of 2018. Additional sediment amounts released are anticipated to be anywhere in the range of 45,100 CY to 137,105 CY to the North Fork of the Gunnison. This could have a potentially negative effect on fisheries especially in the potential event of insufficient snow totals resulting in low spring flows. The BOR plans to release sufficient flows to aid in flushing the deposited sediment during the spring runoff.
WSCC will continue to conduct water quality monitoring throughout the construction window. We will also be conducting macroinvertebrate sampling at three sites near Paonia Reservoir in October. We have recently become the recipients of a very generous donation of water quality testing equipment which will allow us to increase our suite of sampling analytes and site mobility in the future. Please contact Jake Hartter, Watershed Coordinator to learn how you can help be a part of our water quality sampling team.
Please review the documents and links below for background information regarding this important project. Contact Jake Hartter at WSCC for more info and be sure to join us at Memorial Hall in Hotchkiss on August 15th, 7pm.
Images provided by Bureau of Reclamation.