Wednesday, September 5, 2012

Muddy water in the Big Ditch

Jill and I were fortunate enough to get invited on a Colorado River trip through the Grand Canyon, which might be our favorite adventure. Sixteen of us launched from Lees Ferry on August 17, and we took out at Pearce Ferry on August 31. It was a fast-paced trip; we floated 280 miles in 15 days. I was at the oars on an 18-foot raft. Jill kayaked a few days and shared some time on the oars as well. She had hoped to spend more time kayaking, but the water turned out to be so muddy that kayaking wasn't very pleasant.
For the first week of the trip, Arizona was experiencing unusually wet weather. Some monsoonal flow with afternoon storms is typical in August, but what we got was way over the top. We had rain six out of the first seven days, including some long steady rainstorms that are unusual for the desert. Two significant tributaries to the Colorado -- the Paria River and the Little Colorado River -- experienced extended flash flood conditions for days at a time, dumping huge amounts of muddy water into the main Colorado. Here are the flow graphs for the Paria and the Little Colorado... over ten times their typical flows!

The exceptionally muddy water made it difficult to read some of the rapids; instead of frothy whitewater to highlight rocks and pourovers, the waves were the same brown color as the rest of the river. The waves also tend to be slightly smaller, because the water is denser due to the entrained silt and mud.
We had six rafts in our group, four 18-footers and two 16-footers. One raft flipped in House Rock Rapid, and two rafts flipped in Hermit Rapid. Only the 16-foot rafts flipped, hmmm... I managed to keep my raft right side up, though in Hermit I thought we were going over for sure; the waves were the biggest I'd ever run. Hit it square and hope for the best! The waves in Hermit get largest when the river flow is 17-19000 cfs; it was about 19000 when we ran it. The daily releases from Glen Canyon dam cycled between 9000 and 17000 cfs. Other rapids get easier at these flows, notably Horn Creek and Bedrock. We all ran Lava Falls (nominally the most difficult rapid in the Canyon) on the classic right-hand line without incident.
And what would a Grand Canyon trip be without costumes? Big thanks to Shane for inviting us...

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