Dam Removal – Necessity or Biohazard?

Dam removals across the world are making the headlines, but the process isn't always easy and the bigger the project, the higher the risks

Photo credit ciboulette

Dam removal is a hot topic in today’s environmental news, and with good reason. Dams across the world are being torn down in hopes of restoring ecosystems and bringing back a natural balance. In Europe alone, 2022 saw a record number of dams being removed, with a reported 325 being taken down across 16 countries.

The removal of these dams is part of a global effort to revitalise rivers. The dams were originally built to produce hydropower, control flooding, irrigate the landscape and aid navigation. However, they also contribute to loss of biodiversity and a decline in native species, and the older ones can be hazardous. The older a dam is, the weaker its structure becomes, making is less safe as a whole and costlier to maintain. And of course, the longer the dam is in place, the more sediment builds up.

California’s Klamath River, which is having no fewer than four dams removed in one of the largest dam removal projects in history, is making headlines for all of these reasons. According to American Rivers, the four dams are being removed as they have been ‘blocking fish migration, encroaching on indigenous culture and harming water quality’ for the past 100 years'. Removal of the dams will allow nature to take its course, allowing rivers to flow freely and migrating fish to reach breeding areas.

Dr Ann Willis, California Director at American Rivers, said:

‘We are about to witness healing on a major scale. Dam removal is the best way to bring a river back to life. The Klamath is significant not only because it is the biggest dam removal and river restoration effort in history, but because it shows that we can right historic wrongs and make big, bold dreams a reality for our rivers and communities.’

An update by the Klamath River Renewal Corporation on February 16th, 2024 stated that the Copco 1, JC Boyle and Iron Gate dams had fully completed the drawdown process (had their reservoirs drained), which needs to take place before the dams can be deconstructed later in the year. The corporation stated:

With the reservoirs emptied, the Klamath river now winds its way through the former reservoir footprints, cutting through a century of accumulated sediment and finding its historical path. Extensive testing of the sediment that had accumulated behind the dams revealed that it is predominantly dead algae and is not a concern for human health.’

Most reports on the Klamath dam removal projects seem to have a positive outlook, but the healing doesn’t come right away and locals have been left reeling. Dam removal is not a straightforward process, and the bigger the project, the greater the risks. An article in the California Globe on February 19th this year called the undertaking an ‘environmental disaster’, claiming that taxpayers and locals are being left to clean up the mess being made by those not directly involved. According the article, the pros of the dam removal are being overshadowed by the huge mess it is leaving in its wake.

‘I’ve been around natural disasters all of my life, and I’ve never seen anything like this,’ Siskiyou County Supervisor Ray Haupt told the Globe. ‘The river is essentially dead, as is everything in it.’

Residents have also been reported to have concerns, with many seeing dead fish stranded in the mud and deer getting stuck trying to reach water. The Copco Lake has also been left almost dry and residents are mourning its loss, fearing for the local wildlife and the migratory birds when they see that the lake they have come to rely on is gone. The problem, it seems, is that the project has been carried out too quickly and officials have ignored the sheer amount of sediment that would be left behind. Crews were supposed to be allowed to assist with sediment evacuation by using jets of water to and shovels to remove the mud in chunks as the water dropped off. However, the drawdown happened too fast for this to be possible.

In an interview with Smart Water Magazine Senior Researcher of Hydrology and Water Resources at UNU-INWEH, Dr Duminda Perera, summed up the global dam situation as a whole:

‘Ultimately, value judgements will determine the fate of many of these large water storage structures,’ he said. ‘It is not an easy process, and thus distilling lessons from and sharing dam decommissioning experiences should be a common global goal. Lack of such knowledge and lack of its reflection in relevant regional/national policies/practices may progressively and adversely affect the ability to manage water storage dams properly as they age.’