Chile on Friday opened its case against Bolivia at the UN’s highest court over a river both claim rights to, saying La Paz’s demand for Santiago to pay for the use of its waters was “absurd”. The latest water sharing row between the South American neighbours is over the Silala, a small but important cross-border river. “On analysis, Bolivia’s contention is with respect, absurd,” Santiago’s representative Ximena Fuentes told the International Court of Justice based in The Hague. “The concept of… exclusive sovereignty has no place in the law of international water courses,” Fuentes told the judges. Chile wants the ICJ to declare the Silala an “international water course” and give it equal rights to its waters. Santiago claims it has been denied those water rights since 1999. Back in 2016 it dragged La Paz before the Hague-based ICJ — set up after World War II to rule in disputes between countries. In a legal game of ping-pong, Bolivia then counter-sued Chile, asking the ICJ to rule that it had “sovereignty… over the artificial flow of Silala waters engineered, enhanced, or produced in its territory,” — and demanded that Chile pay compensation. Former Bolivian president Evo Morales also previously sought to use the dispute over the river as a bargaining chip in Bolivia’s larger fight to gain access to the Pacific Ocean, which it lost to Chile in a war in the 19th century. But the ICJ in 2018 sank Bolivia’s bid for entry to the sea, saying Chile had “no case to answer” as it was “not legally obligated to negotiate such a move”. At the time Morales threatened to reduce the flow of the Silala into Chile’s parched Atacama desert and impose fees for its use. Connections between the neighbours remained frayed. Chile and Bolivia have had no diplomatic relations since 1978 when Bolivia’s last attempt to negotiate a passage to the Pacific broke down in acrimony. Fuentes, Chile’s vice foreign affairs minister, said Santiago had previously also tried to reach an agreement with La Paz over the Silala without success. Chile in 2000 proposed to formally negotiate the use of Silala’s waters and was willing to pay for it but those discussions stalled when Bolivia raised the price. Fuentes said faced with the consequences of global climate change and fresh water becoming scarcer, “countries are called upon to cooperate in the efficient management of shared water resources.” “The Silala case, however small the Silala river may be… provides the court with a viable opportunity to confirm certain basic principles of international law for shared fresh water resources,” Fuentes said. “Principally that all states have a reasonable and equitable use of an international watercourse and that the law does not permit an upstream state to charge its downstream neighbour for controlling the flow of such a water course,” she said. The hearings are set to continue next week, with Bolivia stating its case on Monday.