Abstract. In the early 19th century, the Dutch colonial power started to build irrigation works. A main problem for Dutch irrigation engineers on Java was how to ensure that the structures they built remained intact. The peak discharge regime of a river was an issue closely related to dam safety. Modifying the approach of Swiss engineer Lauterburg (1877), Dutch irrigation engineer Melchior developed a methodology to determine design peak flows of Javanese rivers. The Melchior methodology has been the standard method throughout the colonial period, despite sometimes severe criticisms on its appropriateness. In independent Indonesia, the approach developed by Melchior continues to be applied. This paper discusses and explains the endurance of the method developed by Melchior. The focus is on the scientific interaction between different participants. The paper shows how participants from these circles debated and which arguments they exchanged.