Study of reservoir sedimentation due to volcanic eruption and its management

Abstract

The sedimentation in reservoirs is mainly caused by sediment inflow from land erosion, riverbank erosion and volcanic eruption. The objectives of this research are to study reservoir sedimentation using the average end-area method for reservoir volume calculation, and to study sediment management in reservoirs and their catchments. This research was conducted in Wlingi and Lodoyo reservoirs, located near Mt. Kelud, one of the most active volcanoes in Indonesia. The assessment reveals that both reservoirs are severely affected by eruptions of Mt. Kelud. The total remaining capacity of Wlingi reservoir in 2015 was 2·20 million m3, which corresponds to 9·2% of the initial capacity. The total remaining capacity of Lodoyo reservoir in 2015 was 1·33 million m3, which corresponds to 25·8% of the initial capacity. Sediment management strategies of both reservoirs consist of methods to reduce sediment inflow from upstream, methods to minimise sediment trapping, and methods to recover the reservoirs’ storage.

The Use of Dam Environmental Vulnerability Index (DEVI) for Assessing Vulnerability of Bengawan Solo Watershed, Indonesia

“…In the last three decades, land use change has caused severe land degradation (Marhaento et al, 2017) that led Bengawan Solo to be one critical watershed in Indonesia. For example, high sedimentation rate in the downstream was reported due to land use change (Soemitro et al, 2020), volcanic eruption (Hidayat et al, 2018), and morphology change such as erosion (Maulana et al, 2019). In respond to Bengawan Solo condition, Indonesian government in 2009 had categorized Bengawan Solo as a critical watershed that should be restored (Ministry of Forestry, 2009).…”