Brazilian scientists report finding a possible 3,700-mile-long river flowing 13,000 feet beneath the Amazon River, the Associated Press says.

Based on temperature variations at 241 inactive oil wells, researchers identified water movement more than two miles deep and running nearly the length of the world’s second longest river, said Valiya Hamza of Brazil’s National Observatory, for whom the presumed subterranean river was named.

If the find is confirmed, which is expected by late 2014, the underground flow indicates the Amazon rain forest has two drainage system running west to east.