Jacques Dumarçay An article published in the Journal of Volcanology and Geothermal Research in 2000 brought new arguments in support of the theory that the Borobudur temple once was surrounded by a lake - a theory which has long been favoured by archaeologists, notably Nieuwenkamp in 1931. J. Dumarçay brings to the fore archaeological evidence, discovered during the 1950s to 1970s (buildings, tombs, ceramics, stupas, and plants) which show that the presence of a lake seems impossible. However, it had probably been planned, during the first phase of the construction of the Borobudur, to divert the course of a nearby river (the Kali Silang) in order to establish a moat around the monument, traces of which are still found on its northern side.