Dams at increasing danger of collapse due to climate change and conflict

By Micha Werner and Yasir Mohamed

With the frequency and severity of extreme weather events increasing due to climate change, many of the 70,000+ dams in the world are at a higher risk of failure. Additionally, the majority of the world’s dams are now aging. In conflict zones, where maintenance may be absent, or where as in the case of Jebel Aulia dam in Sudan, operators have abandoned dams due to these being in rebel-held territory, there is an increased risk of further collapses, with catastrophic impacts.

Dams have been built to regulate rivers for centuries, and despite the many negative consequences, dams and the reservoirs they create have a critical role in managing water resources, supporting water supply to towns and cities, irrigated agriculture, energy generation, and several other purposes. Dams can also be very effective in reducing floods when well operated. Recent research shows that the world’s dams can reduce the number of people exposed to projected increases of global flood risk due to climate change by 13-21%.

The changing climate poses a significant risk through increasing the probability of failure. Some 65% of the dams included in the 2017 GRAND v1.3 database of world dams are over 50 years of age. For the vast majority of dams, it is not clear what climate and hydrological data was used to design the dam and its spillways. This is particularly a concern in areas where such data is scarce, as for example on the African continent. Additionally, the climate has already changed significantly since the majority of dams were built, and in many parts of the world extreme floods are projected to further increase in frequency and severity. In many cases, dam spillways will not be able to cope, leading to an increased likelihood of failure and risk of catastrophic flooding. Adaptation of dams, through increasing the capacity of spillways, or even decommissioning is hugely expensive and slow.

Failure of any of these major dams would have catastrophic consequences, adding to an already extremely difficult humanitarian situation in the country. Whether any of these dams is at an immediate risk of failure is unclear, but the additional risk is a grave concern.

The impacts of a dam collapsing are catastrophic. Arbaat and Derna were both small dams. Seventy-three percent of the world’s dams are larger. The increasing risk of failure due to climate change calls for increased attention and investment. Particularly where that risk is aggravated further by conflict and instability, more effort is needed. The collapse of a dam and the suffering this causes can be averted, but appropriate action needs to be taken.