POSTED BY ERIC SPRAGUE ON MAY 11, 2023
If you intend to spend time on the Dolores River below McPhee Reservoir, please read this entire post. We’ll be updating here twice weekly, usually on Tuesdays and Thursdays, and this is the best source of information on downstream releases from McPhee. At the bottom of this post are some links to flow data sources and recreational organizations including Dolores River Boating Advocates and American Whitewater. These organizations can tell you more about what to expect floating the Dolores downstream of McPhee.
This message has not changed significantly from Tuesday’s update.
McPhee is still releasing approximately 3,400 CFS, which is where releases are expected to remain through Tuesday, May 16th, when we’ll provide further updates. For planning purposes, raftable flows (1,200 CFS or more) are expected to continue through Memorial Day weekend. Be aware, this is just a forecast, and the true length and volume of the spill remain unknown. The first half of the spill will have more certainty than the second half.
Cool, cloudy weather has slowed inflows, and McPhee is currently sitting at a water surface elevation of 6918.9 FT. This weather is expected to persist into next week. Storms and other low-pressure systems like we’re in tend to reduce the daily peak temperature and the sunlight that reaches the snowpack. This slows the melt and tempers the runoff for a time, even as more precipitation is potentially being added to the basin. This introduces more uncertainty into river forecasts; for example: the influence of these kinds of systems can be inconsistent across the basin and the reduction of measured flows can obfuscate the typical trends in the hydrograph that hydrologists look for as signals of upcoming flow changes.
As always, there is uncertainty in the forecasted inflows; if the reservoir rises faster than current predictions, there is the possibility that releases will increase to control reservoir elevation, possibly to around 4,000 CFS. With the reservoir relatively full, operators are balancing outflows with inflows to minimize reservoir gains, and so lose some discretion in regards to release rates. This is especially true this year, when low snowmelt has filled the reservoir weeks earlier than predicted. If recreating on the river, be aware that releases below McPhee can change at any time, though operators will endeavor to minimize unannounced changes.
As usual, we will continue to monitor conditions and will update this page as the spill progresses.
The following is a message from Dolores River Boating Advocates:
As releases from McPhee exceed 3,000 cfs, the water becomes swift with limited eddys. It is important to be aware of your location on the river, especially if navigating through Snaggletooth or the rapids below Gateway. Camps will become inundated in some cases, and in others hard to catch or overgrown.
Potential hazards include bridges (notably a county road bridge below the Slick Rock takeout, a country road bridge a few miles below the Big Gypsum boat ramp, and the highway 141 bridge in Gateway.) Additionally, as the river rises, logs and wood will become mobilized and possibly create strainers and hazards. Further, in some areas, the channel may be braided, and it is important to be alert and aware of various options.
As flows increase or decrease, be sure to be aware of fluctuations and tie your boats up appropriately. Always bring necessary safety gear, and required equipment including a groover and firepan.
For more details on the current official forecast, go to https://www.cbrfc.noaa.gov/wsup/graph/front/espplot_dg.html?year=2023&id=MPHC2
Dolores Gage: https://waterdata.usgs.gov/nwis/uv?09166500
McPhee Elevation & Capacity: https://dwr.state.co.us/surfacewater/data/detail_tabular.aspx?ID=MCPRESCO&MTYPE=STORAGE
Dolores below McPhee: https://dwr.state.co.us/surfacewater/data/detail_graph.aspx?ID=DOLBMCCO&MTYPE=DISCHRG
Slickrock Gage: https://waterdata.usgs.gov/nwis/uv?09168730
Bedrock Gage: https://waterdata.usgs.gov/nwis/uv?09171100
Bureau of Land Management: https://www.blm.gov/visit/dolores-river-srma
The BLM has a detailed boating map of the Dolores river posted on their website. Link below.
BLM Avenza Map page for the Dolores: https://www.blm.gov/documents/colorado/public-room/map/colorado-dolores-river-100k-boating-map-17×40
The following are links to the American Whitewater River Inventory pages for the lower Dolores River: