For decades it was the only freshwater dolphin species in the world not considered threatened by human activity. The tucuxi of the Amazon held out even as similar species in South America and Asia were dammed in, poisoned, or killed as bycatch; one is considered to have gone extinct.
Now, the tucuxi (Sotalia fluviatilis) has finally succumbed: in the latest assessment for the IUCN Red List of Threatened Species, this river dolphin has been declared endangered, with threats arising from entanglement in fishing nets to damming of rivers. Those are the same factors that threaten the pink river dolphin (Inia geoffrensis), with which the tucuxi shares a habitat and which was itself declared endangered in 2018.
The pink river dolphin, famous for its color and a central figure in Amazonian folklore, is more docile and an easier subject for scientists to study. Researchers are now seeking to find out more about each of the two Amazonian dolphin species and understand their peculiarities.
A study published in 2019 estimated an abundance of both species in the Tefé River and Lake Tefé, which lie in the interior of Brazil’s Amazonas state. It found that the tucuxi
— source news.mongabay.com | Sibélia Zanon | 21 Apr 2021
The tide has shifted on dams. Once a monument to our engineering prowess, there’s now widespread acknowledgment that dam-building comes with a long list of harms. Some of those can be reversed, as shown by the 1,200 dam removals in the past 20 years.
But the future of our existing dams, including 2,500 hydroelectric facilities, is a complicated issue in the age of climate change. Dams have altered river flows, changed aquatic habitat, decimated fish populations, and curtailed cultural and treaty resources for tribes. But does the low-carbon power dams produce have a role in our energy transition?
That’s a question some environmental groups and the hydropower industry have been discussing for the past few years, and it’s resulted in a joint effort to work together on increasing the renewable energy potential of existing dams while helping to minimize their environmental harm.
It’s just one effort to rethink the future of dams. Here’s what else to keep in mind:
The removal of Marmot Dam. (Photo by Portland General Electric, CC BY-ND 2.0)
— source therevelator.org | Tara Lohan | Oct 28, 2020
The development of small hydropower dams is widespread throughout Brazil and elsewhere in the world, vastly overshadowing large hydropower projects. The proliferation of these smaller dams is a response to growing energy and security needs. Their expansion, however, threatens many of the remaining free-flowing rivers and biodiverse tropical regions of the world — interrupting the migrations of freshwater fishes, on which millions of peoples’ livelihoods depend. The findings confirm that small hydropower plants are far more responsible for river fragmentation than their larger counterparts due to their prevalence and distribution. small hydropower dams greatly outnumber large hydropower dams, but their combined energy output is much less.
In Brazil, small hydropower plants only account for only 7% of total generation capacity even though they represent more than 85% of hydropower plants in the country. It is projected that river fragmentation will increase by 21% in the future, and two-thirds of the 191 migratory species assessed in the study occupy river basins that will experience greater connectivity losses.
— source University of Washington | Jan 27, 2021
In a victory for indigenous people in Brazil, a court has suspended the license for one of the world’s largest hydroelectric dams, just weeks before operations were due to begin. The Belo Monte dam would divert one of the Amazon’s last major free-flowing waterways. Indigenous groups have long protested the dam, saying it will cause environmental devastation and mass displacement. On Thursday, a judge suspended the dam’s license and fined the company, Norte Energia, and the Brazilian government for failing to provide adequate support to indigenous groups impacted by the dam.
As torrential rains in China continue to wreak havoc on more than 24 provinces, notable Chinese hydrologist Wang Weiluo (王維洛) has questioned the safety of the massive Three Gorges Dam, warning that it could collapse at any moment.
In southern China, regional rainstorms and mudslides that began on June 1 have uprooted more than 7,300 houses and affected nearly eight million people as of Monday morning (June 21). The immediate economic loss is estimated at 20.6 billion RMB (US$2.9 billion) by local officials.
The nonstop downpours have also raised the Chinese public’s concerns over the potential bursting of the world’s biggest hydropower project. Despite government assurances that the dam is structurally sound, Wang has taken an opposing view and claimed that the facility is not as stable as many have been led to believe, reported New Talk.
— source taiwannews.com.tw | 2020/06/22
Over 11,000 people in central Michigan were evacuated from their homes on Tuesday and Wednesday as historic rains swelled the Tittabawassee River and breached two aging and neglected hydroelectric dams. The Edenville Dam collapsed Tuesday evening, and the downriver Sanford Dam was in danger of collapsing as of Wednesday night, according to county officials. Media footage of downtown Midland has shown streets and buildings submerged in as much as 12 feet of water. Several bridges have collapsed across Midland County, and dozens of roads are washed out, making it nearly impossible for trapped residents to flee. The smaller adjoining Rifle River in Arenac County had also swelled to record levels, forcing door-to-door evacuations.
— source wsws.org | Matthew Brennan | 21 May 2020