actually, the lesson from Helene is the opposite from that being promoted.
In 1933, the Tennessee Valley Authority was given the mandate for flood control in the valley of the Tennessee River and its tributaries. Over the next 40 years, they built 49 dams, which, for the most… https://t.co/ReG402Ye86
actually, the lesson from Helene is the opposite from that being promoted.
In 1933, the Tennessee Valley Authority was given the mandate for flood control in the valley of the Tennessee River and its tributaries. Over the next 40 years, they built 49 dams, which, for the most part, accomplished their goal. Whereas floods in the Tennessee were once catastrophic, younger people are mostly unaware of them.
The French Broad River (Asheville) is an upstream tributary where flood control dams weren’t constructed due to local opposition.
Rather than the devastation of Hurricane Helene on Asheville illustrating the effect of climate change, the success of the flood control dams in other sectors of the Tennessee Valley illustrates the success of the TVA flood control program where it is implemented.
Hurricane Helene did not show the effect of climate change, but what happens to settlements in Tennessee Valley tributaries under “natural” flooding (i.e. where flood control dams have been rejected.)
I should add that, in its first 40 years, the TVA built 49 flood control dams, of which 29 were power-generating. In the subsequent 50 years, TVA built 0 flood control dams, However, in the 1980s, they established the Carbon Dioxide Information Centre (CDIAC) under their nuclear division, which sponsored much influential climate research, including the CRU temperature data (Phil Jones) and Michael Mann’s fellowship from which Mann et al 1998 derived.
In 1990, the parents of Crowdstrike’s Dmitri Alperovich moved from Russia to Chattanooga, Tennessee, where his father was a TVA nuclear engineer. Dmitri moved to Tennessee a few years later.
One can’t help but wonder whether TVA’s original mandate for flood control got lost in the executive offices, attracted by more glamorous issues, such as climate change research. If so, one could reasonably say that a factor in the seeming abandonment of TVA efforts to complete its original flood control mandate (e.g. to French Broad River which inundated Asheville) was partly attributable to diversion of TVA interest to climate change research, as opposed to its mandate of flood control.
another thought. As soon as the point is made, it is obvious that flood control dams have reduced flooding. Not just in Appalachia. I’ve looked at long data for water levels in Great Lakes and the amount of fluctuation (flooding) after dams installed is much reduced.
And yet my recollection of public reporting of climate is that weather extremes, including flooding, is getting worse. But in areas with flood control dams, it obviously //isn’t// getting worse than before. It’s better. Note to self: check IPCC reports for their specific findings on flooding.
Here is a diagram of the proposed system of dams and reservoirs proposed to provide flood control for Asheville – located in center of diagram (h/t reader Jack Brown). This was the project that was abandoned in the face of some local opposition. To be fair, it is my understanding that the wild rivers are very scenic, but the flood risk in the watershed was well known from the flood of 1916 and seemingly ignored by state and local governments.
@Revkin also cites NYT article on development in North Carolina zones known to be at risk
Andy Revkin reports on fascinating 1960 report on https://x.com/Revkin/status/1841936334891385070 entitled “Floods on French Broad and Swannanoa Rivers around Asheville,
Andy reported that the report stated that developments around Asheville “would cause these great floods of the past to be higher if they occurred again. Land fills and buildings in the flood plain and the many bcidges across the streams have seriously reduced flood flow capacity.” “On the French Broad River a flood of the same discharge as the 1916 flood would today be 3 to 4 feet;.higher between Pearson Bridge and West Asheville Viaduct than the actual flood elevation. On the Swannanoa River, a repetition of the 1916 flood would be up to 2. 5 feet higher today at Biltmore and up to 15 feet higher upstream from the Recreation Park dam.”
A corollary is that the contribution of site development to any modern “record” flood level has to be accounted for before comparing to past record levels.
To understand the baseline risk of flooding around Asheville, Buncombe County and surrounding steep-sloped, fast-developing regions of WNC, I recommend this incredible 1960 (!) @TVAnews report – “Floods on French Broad and Swannanoa Rivers around Asheville,… pic.twitter.com/MtOkTYr63w
