Flows will be ramped up to at least 800 cubic feet per second by early Friday morning, and will remain at that level through Sunday, June 5.
Reservoir managers said the recreational release could lengthen, and flows may go higher as the reservoir fills and water is send downriver.
The spill was delayed until warm weather brought the runoff forecast into focus.
A peak is expected in June on the Upper Dolores River as mountain snowpack melts off.
It takes a few hours for release to reach the Bradfield Bridge put-in and other boat ramps.
The release will taper off late Sunday, ramping down from 800 cfs to 600 cfs over two days. From there the river will drop down to 400 cfs over two days, then 200 cfs and finally 65 cfs. Minimum boatable flows for rafts is 800 cfs to 600 cfs; for kayaks minimum flow is 300 cfs to 400 cfs.
Smaller rafts and kayaks could enjoy a 5-7 day run in the 100-mile canyon below McPhee.
After Sunday, decisions about releases will be posted on the McPhee Reservoir website.
Documentary filmmaker Rig to Flip have been monitoring the Lower Dolores and has identified and photographed a new boulder field and rapid upstream of the Dove Creek pump house and boat ramp.
For release updates, go to http://www.doloreswater.com/releases.htm
Updates are also available from the Dolores River Boating Advocates at at http://doloresriverboating.org. Stream-gauge data is available at the Division of Water Resources at http://bit.ly/1Vzrmv0
jmimiaga@the-journal.com.