23. Trying to Contain Kelut
The colonial government of the Dutch East Indies responded by creating a volcanological authority to study and warn about future eruptions. It also launched an ambitious engineering project to avert future devastation. The authorities created a drainage system for Mount Kelut’s crater lake, to manage the hazards and potential future mud flows, in case of another eruption. Drainage tunnels were dug, which reduced the crater lake’s water level by about 150 feet, and they proved highly effective. The next time Mount Kelut erupted, which happened in 1951, there was too little water in the crater lake to form massive flood flows, thus averting what would have been another Kelut disaster.
The drainage tunnels were destroyed in that 1951 eruption, however, and were not immediately rebuilt. When Kelut erupted again, in 1966, the crater lake had refilled and contained over 50 million cubic meters of water. In the resultant lahars, over 200 people were killed by the mud flows. The Indonesian authorities responded by digging a new, and deeper tunnel, which reduced the crater lake’s volume to only 1 million cubic meters of water.