The largest dam removal project in US history will restore free passage for salmon along 400 miles of the Klamath River, revitalising vital habitats for the species.

For the first time in over 100 years, salmon will soon have unrestricted access to the Klamath River and its tributaries, marking a significant step in the largest dam removal project in US history. The project, taking place along the California-Oregon border, will restore the natural flow of the river, allowing salmon to return to crucial habitats just in time for the fall Chinook spawning season.

In the coming days, excavation teams will breach rock dams that have been diverting water upstream of two already removed dams—Iron Gate and Copco No. 1. This will allow the river to flow freely through its historic channel. The removal effort follows decades of advocacy from Native American tribes, including the Karuk Tribe, who have long fought for the restoration of the river and its salmon population.

Leaf Hillman, ceremonial leader of the Karuk Tribe, called the restoration “a good omen for our future,” noting the deep cultural and spiritual significance of salmon to the tribe. The demolition work is part of a broader initiative across the United States to restore river ecosystems by removing aging dams that obstruct natural habitats for fish and other wildlife.

The Klamath River, once the third-largest salmon-producing river on the West Coast, has faced a steep decline in fish populations due to the construction of power-generating dams by PacifiCorp between 1918 and 1962. These dams halted the river’s natural flow and disrupted the salmon lifecycle, leading to dramatic population declines. In 2002, a bacterial outbreak linked to low water levels and high temperatures wiped out over 34,000 Chinook salmon, prompting a new wave of advocacy and, ultimately, the approval for dam removal in 2022.

The project has already seen some successes, including the removal of Copco No. 2 dam and draining of the reservoirs behind the remaining structures. The total cost of the dam removals is expected to reach $500 million, funded by both taxpayers and PacifiCorp ratepayers. Despite the relatively small energy output of the dams—less than 2% of PacifiCorp’s total capacity—hydroelectric power generated by dams has long been considered a clean, renewable energy source. However, increasing concerns over the environmental impact on river ecosystems have led to the removal of several major dams in the West.

The full restoration of the Klamath River will take time, and experts remain cautious about how quickly salmon will return to their historical habitats. While some salmon have already been spotted at the river’s mouth, it’s uncertain how long it will take for them to reach their former spawning grounds.

Mark Bransom, CEO of the Klamath River Renewal Corporation, which is overseeing the project, noted that similar efforts, such as the removal of the Elwha River dams, took years to show tangible results. “You can’t undo 100 years of damage overnight,” Bransom acknowledged, though he remains hopeful for the long-term recovery of the river and its fish populations.

A dolphin, nicknamed Jo Jo by locals, was spotted swimming in west London before being found dead, along with another in Greenwich.

Two dolphins have been discovered dead along the River Thames, after being seen swimming through areas of west and south-east London. One of the dolphins, nicknamed Jo Jo by local children, had been spotted multiple times in the Thames around Hammersmith last Thursday. This sighting raised concerns due to its lethargic and disoriented behaviour.

Mary Tester, a volunteer from British Divers Marine Life Rescue (BDMLR), confirmed on Monday that two dead dolphins had been found in recent days. One was located in Battersea on Sunday, which is believed to be Jo Jo. Another dolphin was found at Greenwich, and both are thought to belong to the same pod of adult common dolphins.

Earlier, social media users reported seeing two dolphins “playing” in the water near Greenwich and Deptford Creek on Tuesday and Wednesday. The same dolphin, Jo Jo, was then observed swimming between Hammersmith and Wandsworth Park, with reports describing it as unusually sluggish.

While there have been reports of a third dead dolphin, its identity has yet to be confirmed, leaving some uncertainty about the total number of affected animals.

Ms Tester expressed concern over the growing frequency of dolphin sightings in the Thames, which is becoming a troubling trend with no established rescue protocol. She highlighted the difficulties of intervening when dolphins are spotted in the river, as there are legal complexities and a lack of permissions from river authorities for BDMLR to act.

The BDMLR currently has a team of 5,000 volunteers across the country who typically respond to strandings. However, encountering dolphins alive but stranded in the river presents unique challenges, and Ms Tester hopes for a clearer strategy to assist dolphins in distress.

There are plans to conduct post-mortems on the deceased dolphins to help determine the cause of their deaths, with possibilities including pollution, illness, or starvation. Ms Tester noted that while seeing dolphins in the Thames is exciting, it also serves as a “red flag” for the ecosystem’s health. Dolphins are not typically found this far up the river, and their presence often signals a larger environmental concern.

So far this year, five pods of dolphins have ventured beyond the estuary into the Thames, with three making it to London. Unfortunately, all three pods have not survived, and this latest case adds to the concerning trend.