The Grand Canyon Flood of 1996

I admit that I was a big-time skeptic when I first read about it. The Bureau of Reclamation was proposing to "scour" the many years of built-up sediment from the bed of the Colorado River below Glen Canyon Dam, to rebuild the beaches in the Grand Canyon! A week-long flood -- a release of 45,000 cfs -- was scheduled to begin on March 26. Many commercial rafting companies began scurrying around to schedule "training trips" for their guides. Nobody had seen that kind of water since the nearly disastrous flood of 1983.

We had camped on the beaches in the summer of 1982 and then again on another run in 1984. The campsites had taken a real beating in 1983. Many of the popular camps had beaches carried away by the record post-dam flow of almost 100,000 cfs. The flow for our run in 1984 was around 42,000 cfs -- a leftover from 1983. We were somewhat intimidated by the big boils and whirlpools. The eddy fences alone could flip a raft. Crystal did flip two boats. Hermit was awesome. We found some of our planned camps completely submerged; others badly eroded.

The problem is that the river in the Grand Canyon no longer carries the incredible silt load it once did. All of that is now dumped at the upper end of Lake Powell. The river no longer can swell to flows of over 100,000 cfs in the spring to cover the bars and beaches and deposit new stuff. Releases from Glen Canyon Dam, after 1963, were dictated by power generation demands, and little else. When all the air conditioners came on in the morning in Phoenix, the dam started releasing, and then shut down in the evening. You can sell electricity for more when the demand is high. This practice became known as "peaking power." Daily "tides" could change the river level by ten feet! This was disastrous to the beaches, probably more so than the 1983 flood, even though the process was slower. The high tide would saturate the sand, and when the river dropped, the heavy waterlogged bank would slide downslope, to be carried away by the next cycle. It seemed only a matter of time until many of the popular camps became a bed of boulders. Many of them were almost there. It is estimated that 40% of the total sand had been lost.

A few years ago, some genius figured out what peaking power was doing to the Canyon. Somehow, the controlling agencies have been forced to moderate daily fluctuations, but a daily rise and fall still occurs.

We had a trip in mid-May this year and we were eager to see firsthand the results of the experiment, not trusting the bureaucratic claims. How could the river bottom sediment be churned up, held in suspension, and then nicely deposited in the right places without carrying away more of what was still left? The theory was that the "scour" would simulate a natural spring flood and the built-up deposits in the bottom of the river would become the silt load. No one really knew what would happen, but about $3 million was spent on scientific equipment, researchers, and transportation, not to mention the loss of power generation revenue.

Anyway, the damn thing worked pretty well! Almost all the campsites had new deep sand and many dozens of little spots had sand where none had previously been seen. Almost all of the popular camps saw some improvement. However, the new deposits usually occurred as steep-faced banks. Where a gentle slope had existed, there was often a six or eight-foot-high "dune" face that made it difficult to land and unload boats. We figure that time, traffic and daily tides will slowly knock down the steep faces. For now, some true rejuvenation has taken place. How much silt was added to the upper end of Lake Mead hasn't been learned, but we suspect it was quite a lot. There is talk of another flood in, maybe, five years. Now if we could just get rid of all those airplanes....