The growth of hydro-power projects in the United States has been flat since the 1970s.
That may change with a recent announcement that the Alaska Energy Authority intends to develop a 600MW project on the Susitna River. That project has been under consideration for over 35 years. In the summer of 1979 I was considering paddling Devil’s Canyon in what was only the 4th descent of the rapids. In the end I didn’t go but my paddling buddies enjoyed an experience of a lifetime. We were very concerned at the time there were not many years left before the canyon would be dammed. As it turns out, it was only common sense not mega-development that kept me from ever going back.
The Susitna project is far from a done deal even now.
They are only just scoping out the environmental review process now. What gives me more confidence about the eventual design of the project is that in the 1970s they would have only had a couple of decades of discharge data from Susitna River at Gold Creek to work with whereas they now have another 35 years of data from Gold Creek plus they also have 30 years of data from Susitna River at Sunshine Creek to work with. Having long periods of high quality data from both upstream and downstream of the project site is hugely informative.
I do not know much about the data available to inform the design of mega-projects in Eastern Europe, Asia, Africa, India, and Latin America but I suspect that there will be a much greater reliance on ‘engineering judgment’ in those regions.
Data collection needs to commence long before the serious political and financial discussions do for development of projects on this scale.
Once the political process starts and funding sources are found, there is little enthusiasm for sitting back and waiting 30 or 40 years to collect the needed data. Monitoring agencies need adequate funding so that they can anticipate, and respond to, future need (as USGS has done in this case).
Most mega-hydro projects have turned out to be very effective long-term investments often providing flood control and a reliable source of irrigation water as well as hydroelectric power. The flip side to huge benefits are huge risks if the assumptions implicit in the design are not completely valid. In addition to the risk of catastrophic dam failure there is also the risk of silent failures such insufficient water supply to fill the reservoir to design capacity, sedimentation of the reservoir, and loss of habitat or fish passage resulting in a cascade of environmental degradation. The difference between success and failure may be as simple as the foresight to correctly anticipate future needs for data.