A drowning town: are Bentiu’s dykes high enough to save it from disaster?

Surrounded by towering mud ramparts, the 300,000 residents of Bentiu in South Sudan will spend today, like tomorrow, anxiously scanning the gathering storm clouds. They live in one of the most vulnerable towns on Earth: a sprawling settlement whose streets lie below the water level of a huge lake that is steadily rising on all sides.

Without the dykes built to encircle the capital of the country’s notoriously volatile Unity state , Bentiu would be completely submerged. But fears are mounting that attempts to preserve Bentiu are futile and that it could soon be washed away, potentially with huge loss of life – a catastrophic impact of the climate crisis on a fragile state.

During last year’s wet season – when about 55cm (22in) of rain fell – the surrounding water came within 30cm of breaching Bentiu’s defences.

The forecasts for this wet season – which began in earnest at the end of May – are double that: 110cm. Some projections are for as much as one and a half metres of rain.

Emergency work by 274 Pakistani engineers serving with the United Nations mission in South Sudan (Unmiss) has raised the dykes to four metres or more, but concerns remain that this still may not be enough.

Muhammed Waseem al-Hussain, chief operating officer for the engineers, admits it is a job that comes with significant pressure. “We’ve been busy raising the dykes, constantly checking that they can withstand what is coming.”

Speaking from Unmiss’s headquarters in Juba, 550 miles (900km) south, the force commander, Lt Gen Mohan Subramanian, cuts a worried figure.

Subramanian is continually updated with intelligence on what may happen to Bentiu in the months ahead. “We are trying to improve the dykes to the extent that we will withstand up to 1,100mm of rainfall.

“If it goes beyond 1,100mm, water will overflow the dykes,” he says.

Heightening fears are events unfolding 750 miles south of Juba, where water levels in the Lake Victoria basin, source of the flood waters surrounding Bentiu, are at record levels .

It takes three months for water from Africa’s largest lake, one source of the Nile, to reach Bentiu. Analysts fear that the unprecedented volume of water, combined with the forecast heavy rain, will swamp the city, especially if Uganda’s Jinja dam is overwhelmed and water is released to relieve the pressure on it.

“We’ve already had water released from Lake Victoria by Uganda because of the record levels. We’re looking at calamitous floods in South Sudan in September, October, November,” says Subramanian.

Most at risk is Bentiu’s refugee camp – the largest in South Sudan – where thousands of people initially sought refuge from conflict, but where almost 150,000 internally displaced people (IDP) have now gathered to escape the flooding that has destroyed the region’s farming, traditionally the primary source of food and income.

Many of its refugees have lived here since August 2021, when Bentiu and the surrounding area were first hit by unprecedented flooding caused by the changing climate.

Villages, forests and livestock were engulfed in a matter of days. Since then, the water has not receded; several metres of water covers an area of 5,600 sq km (1.4m acres).

Farmers have had to become fishers. Isolated villages, cut off by the water, are now island communities.

Subramanian says: “In 2021, we had what the worst flood in 60 years. What is being predicted by the government of South Sudan and other agencies right now is the worst flood in 120 years – they’re saying it’s going to be twice as bad as 2021.”

So far, the Unmiss engineers have repaired 60 of the 77 miles of flood defences that surround Bentiu, its refugee camp and the adjoining UN base, as well as the nearby town of Rubkona.

Daily inspections of the mud defences are made by boat.

Taimoor Ahmed, flood and media officer for the Pakistani military engineers, looks over the refugee camp from the summit of a dyke, the water stretching to the horizon, broken only by the bleached trunks of dead trees.

“The work never stops,” he says. His colleague, Hussain, agrees. “But we are confident it will hold.”

If he is wrong, his commander realises that the UN might have to move the entire refugee camp.

Subramanian says: “One of the options is to relocate the IDPs to a higher ground. But there are so many problems because people have rebuilt their livelihoods. We have not yet found a solution, to be frank.”

In the absence of a plan to relocate, Unmiss has begun reinforcing the nearby airstrip by building a secondary dyke around it.

If the runway is submerged, Bentiu risks being stranded without food or any aid. During South Sudan’s wet season the city’s one mud road in and out becomes impassable and up to 20 flights a day are required to keep the town functioning.

After each flight, UN engineers must flatten the runway and add fresh soil to ensure it remains usable: the wreckage of several aircraft beside the landing strip is a reminder of what happens if such work is not done.

In addition, the road has been raised another metre and protected with earth banks on either side to prevent it from being submerged.

Related: The rising cost of the climate crisis in flooded South Sudan – in pictures

Concentrating minds are the events of October 2022, when the refugee camp came close to being inundated after 55cm of rainfall was recorded.

At midnight on 8 October a patrol monitoring the dykes came across a 30cm gap in the defences. “Within one hour, the breach expanded to nearly nine metres. Water was gushing out of it like a river,” says Subramanian.

Hundreds of UN troops and camp residents formed a human chain to stuff the hole with sandbags, in an operation that took 40 hours.

“We were facing the threat of about 30-40,000 people, elderly, infirm or very young children in the IDP camp, drowning and dying,” he adds.

In 2022, disaster was averted. In 2024, the biggest challenge is yet to come.