Tag Archives: Tub Ring

Lake Powell Water Level to Drop 2.5 feet


From November 18-23, 2012, the Department of Interior will conduct the first High Flow Experiment under a multi-year High Flow Protocol announced earlier this year by Secretary Salazar. Under this Protocol, high flow releases are linked to sediment input and other resource conditions below Glen Canyon Dam.

Beginning on the evening of November 18th, releases from Glen Canyon Dam will begin ramping up to full power plant capacity (approximately 27,300 cfs). At midday on November 19th, bypass tubes at Glen Canyon Dam will be opened and releases will continue to increase up to full power plant and bypass capacity (approximately 42,300 cfs) by the evening of November 19th. Releases will be maintained at peak release for 24 hours and then begin ramping back down. Releases will return to normal operations in the evening of November 23rd. The entire experiment, including ramping is expected to last 5 days, with 24 hours at peak release. November releases from Glen Canyon Dam prior to and after the High Flow Experiment are expected to fluctuate between 7,000cfs and 9,000cfs. The elevation of Lake Powell is expected to decrease approximately 2 ½ feet during the 5-day experiment.

For additional information please visit the 2012 High Flow Experiment webpage.


I’m Anne Castle, Assistant Secretary of the Interior for Water and Science. As the Assistant Secretary for the past three years, I’ve had the privilege of overseeing the Bureau of Reclamation and the U.S. Geological Survey. I also serve as the chair of the Glen Canyon Dam Adaptive Management Work Group. The Adaptive Management Program for the Glen Canyon Dam was established in 1996.
Continue reading Lake Powell Water Level to Drop 2.5 feet

Slickrock and Tub Rings

The soft sandstone undulations around the Glen Canyon, Lake Powell and Grand Staircase have a mesmerizing quality to them. They are so unlike the rock that you may see elsewhere in the world, in fact, the slickrock is really not rock at all. It’s a sandstone. To be specific, it is layers of stratified, petrified ocean bottom! It’s ancient beach. The stripes and patterns reflect the flow and direction of different types of sediment and sand, dunes and mudflows. Some of the most famous and recognizable of these formations is in Coyote Butte in Southern Utah towards Kanab.

Lake Powell Slickrock
Lake Powell Slickrock

As a stark contrast to these soft forms is the appearance of the “tub ring”, a salty, alkaline mineral deposit left behind from Lake Powell as its Colorado river water leaches these minerals out of the surrounding land on its way to the reservoir. When the lake level was rising from the day the Glen Canyon dam was completed this ring was not an issue.

Once Lake Powell filled Glen Canyon the fluctuations of water level (drought, flood, water release from the dam) started to reveal this white deposit on the porous shore surfaces.

Lake Powell Slickrock
Lake Powell Slickrock