By Dr. David Gross
Part 20: The future of the Colorado River dams
Our journey from the Fruita Campground to the San Luis Valley took us over the upper reaches of Lake Powell. I assume the engineers and planners who designed, proposed and built the Glen Canyon Dam anticipated the amount of water-borne debris that would end up in the lake. After setting up Frog for the night in Blanca, Colo., I Googled it (the source of all information, right or wrong) to find out how much silt and sediment goes into the lake and what the long-term effects will be. Somewhere between 65,000 and 100,000 cubic yards of sediment reach the lake per year. A study conducted in the mid-1970s, using sonar to measure the sediment, indicated the lake could hold about 700 years of accumulated sediment.
Not surprisingly, I found many articles forecasting doom and destruction while vilifying the engineers and planners who promoted the project. All the arguments seemed well made, to me, and were supported by presumably scientific studies. There were an almost equal number of well-written articles touting the economic, recreational, agricultural and social benefits of the dams, also citing scientific evidence that although the dams could, eventually fail without mitigation, there is no imminent danger. These proponents of the dams argue that there are ways to “flush” the lake using the jet tubes and spillways of the dam.
I don’t have any idea how much accumulation there is at the dam but at Hick’s Crossing, with the level of the lake down considerably, the amount of silt and sediment deposited in the upper reaches of the high water marks was evident, and I could see places where that stuff was falling into the water. After reading those articles I feel strongly…both ways. The controversy about the Colorado River dams and their long-term effects on the environment and water use rages on. What seems apparent is that predictions and study results are equivocal, nobody knows for certain what will happen. If political action or the inevitable progression of nature take away the Glen Canyon and the downstream dams, many predict a domino effect: The mega concentrations of people in Southern California and Arizona, along with the agricultural and recreational enterprises of that area, will be desperate to find water.
The question seems to be more when, than if. Opponents say it could happen two generations from now and could be sudden and catastrophic. Proponents say nothing will happen for many lifetimes, maybe as long as 700 years. I have no idea what to believe but the longer I live, the more I feel that way about most things.
After his losing his wife of 52 years to cancer, Dr. David Gross has embarked on an extended road trip with his new dog, Charlize, and is writing about his experiences.