Happy Dam Removal Day, the time to reflect on and celebrate the progress made in restoring our rivers and the critical biodiversity they support. To date, the damage from 9,003 European dams and weirs has been undone. The success of Dam Removal Europe in drawing global attention to this problem has led the good people at DamRemoval.eu to expand the holiday globally. I’m happy to support and endorse this action.
Dams are outdated, futile, dangerous, and we should remove most of them while prohibiting the construction of new projects.
The United States has removed more than 2,100 dams to date and plans to remove 30,000 by 2050. This is a bipartisan effort that is succeeding in the most contentious of political climates because it’s such a fundamental and important issue, like saving the bees. No one likes flooding or fish going extinct, dam collapses (1,243 emergency incidents or dam failures in the US), or dams running dry as is happening at the Hoover Dam.
You can follow its water level in real time and see that it’s steadily declining, currently 170 feet below full pool capacity. Data from the US government shows that Lake Mead is at its lowest capacity since 1937, when it was in the process of being filled. Climate change is catching up and the conditions that (arguably) made dams useful a century ago no longer apply. I don’t expect the Hoover Dam to be dismantled any time soon, but it may serve as an example, and direct energy investors to explore alternative, stable, and modern means of energy production. Solar and Nuclear Power are now the proven winners while geothermal and hydrogen have their place. Hydroelectric does not.
Irreplaceable Biodiversity
There’s good reason to expect positive reception for this dam removal holiday, especially in Asia where I work. China has removed about 300 dams from a tributary to the Yangtze River, both in an effort to save irreplaceable fish species, and importantly, because stretches of the river were running dry.
Following the release of 20 adult Yangtze sturgeon in April of this year, natural breeding patterns have already been observed. This animal was declared functionally extinct in the wild in 2022 by the International Union for Conservation of Nature; they hadn’t reproduced naturally since 2000 due to hydropower dam development driven habitat loss.
This effort is commendable, the progress made exciting. The idea can be expanded and reproduced. In a similar spirit, better than restoring rivers and wildlife is to not destroy them in the first place. Some river species like the Mekong’s pink dolphin are dwindling to less than 200 in Cambodia. Dam projects are credited with causing the extinction of entire fish species, as with the Chinese Paddlefish. A lot of this damage can’t be undone. Remove dams where we can; prevent new dams everywhere.
Dams don’t just hurt rivers and fish; dams are often built in the middle of densely canopied forest which destroys these habitats and their residents. The dense jungles home to elephants and other endangered wildlife are fragmenting, threatening their migratory and breeding patterns, which is to say their very existence.
Forests, Rain and the Paradox of Dam Deforestation
A primary reason that people build dams is for water security which is self-defeating. Despite conventional wisdom, building reservoirs doesn’t secure the water supply, but instead destroys the forest that regulates rainfall. This phenomenon is explained by the Biotic Pump theory proposed by researchers A. M. Makarieva and V. G. Gorshkov from the Petersburg Nuclear Physics Institute, Gatchina, St. Petersburg, Russia. They explain how forests draw in moist air from the oceans and create rain, the mechanism being the pressure changes caused by the vapor evaporating away. The forests continue to evaporate away water which creates rain further inland which in turn leaves a void for more humid air to fill. This overcomes the conventional thinking about convection heating and explains how ocean air can move from the hotter ocean to the cooler interior, which wouldn’t be explainable with common wisdom. Some western scientists still refuse to accept the Biotic Pump as valid despite experimentation strongly supporting the theory. The Biotic Pump mechanism explains why the Amazon and Siberian forests can stretch for thousands of kilometers inland, bringing much needed rainwater to the interior. The below map illustrates how water vapor is brought inland by the Cardamoms Forest, the source of rain for all of the rest of Cambodia.
Quoting from their original 2007 study that has only been supported by continued research (my bolding): “Replacement of the natural forest cover by a low leaf index vegetation leads to an up to tenfold reduction in the mean continental precipitation and runoff, in contrast to the previously available estimates made without accounting for the biotic moisture pump. The analyzed body of evidence testifies that the long-term stability of an intense terrestrial water cycle is unachievable without the recovery of natural, self-sustaining forests on continent-wide areas.”
They continue to explain the mechanism: “…the low-level air moves from areas with weak evaporation to areas with more intensive evaporation. Due to the high leaf area index, natural forests maintain high evaporation fluxes, which support the ascending air motion over the forest and “suck in” moist air from the ocean, which is the essence of the biotic pump of atmospheric moisture. In the result, the gravitational runoff water losses from the optimally moistened forest soil can be fully compensated by the biotically enhanced precipitation at any distance from the ocean. It is discussed how a continent-scale biotic water pump mechanism could be produced by natural selection acting on individual trees.”
Dense forests regulate rainfall and clearing them destroys water security. Dams block rivers and endanger wildlife, worsen climate change and serve no useful purpose in the modern age. Let us stop building them, and where the damage has been done let us work together to remove dams and undo this disfigurement, restoring nature to how it should be.
