08.4.2022

The Alleged Colorado River Drought

Recent flooding in Kentucky caused VP Kamala Harris to link it to climate change and one resident told Sky News that the flooding is the “worst I’ve ever seen.” That is likely true, but not very meaningful in terms of weather or climate history. … If there is a drought on the Colorado river it is invisible. The massive reservoirs, Lake Powell and Lake Mead, are shrinking because the previously mentioned water hogs are taking too much water.

The graph below shows the 30-year average naturalized flow (blue line). By averaging over 30 years the random changes year by year are smoothed and the long-term climatic trend is revealed.  Also shown is the four year average flow, relevant because the great reservoirs, Lake Mead and Lake Powell, can only store about four years of water consumption.

The graph shows that nothing dramatic is happening. Predictions that there will be a worsening drought are scare stories. There are periods of low flow in the four year average (black line) when storage will be inadequate and water users must be prepared for such events. From 1960 to 2021 the average flow was about 14-million acre feet. The dotted line shows a very slow downward trend in the 30-year average.

Authored by Norm Rogers and published at the CO2 Coalition Blog on 4 August 2022 here.

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