Following the communist purges in the 1960s, thousands of political prisoners were incarcerated in Buru, and they were mostly placed around the Waeapo River valley. This was partly due to the valley's topographic features, being surrounded by continuous steep cliffs. As the river was navigable, it was used to transport prisoners inland. The lower Waeapo valley later became a destination for Javanese transmigrants, with over 20,000 settlers moving into settlements on the Waeapo River's floodplain and establishing rice fields. The Waeapo valley remains the concentration of nearly all rice agriculture in Buru.