Nobody is quite sure how the ferry sank. Ayuen Samuel, who manages the old shipyard in Juba, South Sudan’s capital, thinks it ran aground on this treacherous stretch of the White Nile after snapping its mooring. Others say it was hit by a grenade during the two-decade independence war that ended in 2005. Whatever the reason, the ferry’s husk still sits in the river near the city centre, a rusting symbol of the country’s disappointing trajectory since independence from Sudan in 2011.

The decline of South Sudan’s once-bustling river trade is a measure of the toll that years of conflict have taken on the country, and of how far it remains from economic recovery. Earlier this year fighting erupted in the oil-producing Upper Nile state, the most serious flare-up since the civil war ended in a fragile truce in 2018. In March Salva Kiir, the president, moved to arrest his vice-president and longtime rival, Riek Machar, for “stirring up rebellion”. A return to war would spell disaster for South Sudanese and ruin for the fledgling river trade.

Juba began life as a river port on a bend where the water was deep enough for steamer traffic. In the 20th century cargo tows and passenger ferries plied their trade as far as north as Kosti, in what is now Sudan (see map). Few roads were ever built in southern Sudan, as the marginalised province was previously known, so “the only alternative was inland waterways”, explains Manyok Simon Chol of the River Transport Authority in Juba. At the peak in the 1970s, 250,000 passengers travelled those waters each year.

Trade along the river declined during the independence war, when guerrillas attacked state-owned steamers carrying troops from the north. After independence, things got worse. Angry about the loss of lucrative oilfields, Sudan’s government closed its border and river trade ceased. Plans to modernise Juba’s river port were suspended. When civil war erupted in the capital in 2013, the South African firm building a new passenger terminal left. “Maybe one day they will come back,” hopes Mr Samuel.

Today trade on the river moves on small barges and crab boats. The UN uses bigger ferries for transporting humanitarian aid. Only one of the river shipments handled in 2024 by B&S Group, a logistics firm, contained commercial cargo. Sabit Asholi, its boss, considers river transport a “100% wasted opportunity”. Most of South Sudan’s few paved roads are impassable in the rainy season. The Nile, Mr Samuel notes, could serve as a “natural highway”.

But to restore that role would require investment. In Juba, cargo is still handled by hand. The river is clogged with sand and debris. A boat from Mr Asholi’s fleet recently sank after it crashed into a barge that had capsized during the civil war.

There are signs of tentative progress. A long-awaited expansion of Juba’s port, funded by a $13.5m grant from Japan, began last year. The World Bank is considering funding a plan to dredge the Nile to clear the way for bigger boats between Juba and Bor, some 150km to the north.

The return of war to Juba would scuttle all this. The Japanese contractors expanding the port have already evacuated. For now, the worst violence is far from both the capital and the Nile. Yet if the fighting spreads it may reach Malakal, the riverside capital of Upper Nile state. When the last war arrived there in 2014, more than 200 women and children died after they had rushed aboard a ferry. It swiftly sank.