EDITORIAL

I caught a piece of information while channel surfing the other day that said one in ten of the more than 100,000 dams that block rivers across the USA are considered a risk to human life. And more than 13 percent of those are considered structurally deficient. Dams in the US have a life expectancy of 50 years, and more than a quarter of these have passed their life expectancy after decades of neglect. A breach in most would be catastrophic. Those are horrible-sounding odds. Dams stir up emotions from conservationists and those who will live in their shadow. Sometimes the naysayers might be proved right – the Teton Dam in Idaho was built in a seismically active area and did in fact collapse. Tens of thousands died in China after a cascade of dam collapses. There haven’t been any significant dam collapses in New Zealand – although a break in a natural dam caused the Tangiwai Disaster – but there have been some incidents. Not too long ago Picton was thought to be under threat from a water supply dam in Essons Valley; the Matahina Dam was accused of causing flooding; the Opuha dam breached before it was completed; and in 2016 a wary eye was being kept on a natural dam on the Hapuku River. The writer and conservationist, Douglas Adams, growled, “We must have beaver genes or something... There’s just this kind of sensational desire to build dams, and maybe that should be looked at and excised from human nature. Maybe the Human Genome Project can locate the beaver/dam-building gene and cut that out.”