Overview of watershed development and river sedimentation condition in Sorong, Papua, Indonesia

Abstract

Sorong Regency is developed to be a special economic zone, for enhancing economic in the eastern part of Indonesia. Few studies or investigations, which are related to river sedimentation due to the development, are rarely available. In September 2023, we conducted field investigation to four watersheds in Sorong (Remu, Mariat, Klasaman, and Warsamson Watersheds), in which each of them has different services. The normal flow at the upstream of Remu River was not visually turbid, and the watershed was well conserved for drink water purposes. The Mariat River was visually turbid as the watershed was developed for transmigration and agriculture area, which is likely related to siltation at the downstream segment of the river and sedimentation in the irrigation facilities. The sand mining and washing activities in the Klasaman Watershed are likely related to the difference of visual turbidity of the upstream and downstream river flows relative to the mining site. We think that the erosion protection of manmade slopes are needed to reduce the amount of sediment entering the Warsamson River. Erosion and sedimentation monitoring efforts are crucial and urgent toward sustainable water resources development in Sorong, Papua, Indonesia.