Author(s): Teguh Winari; Kamsiyah Windianita; Didik Ardianto; Fahmi Hidayat; Raymond Valiant Ruritan
Linked Author(s): Fahmi Hidayat
Keywords: Wlingi dam; Sediment flushing; Dam safety
Abstract: Wlingi dam is located in Blitar Regency, East Java Province of Indonesia. It is one of the dams in Brantas river basin. Wlingi dam was built as a retainer of Kelud mountain sediment which is one of the most active volcanoes in Indonesia. In April 2017, sediment flushing was carried out to restore the capacity of Wlingi Reservoir. This study aims to determine the dam safety conditions as the impacts of sediment flushing operation. The study includes visual observation and analysis of the dam instruments. Several instrumentations were installed at Wlingi dam to monitor the behavior of the dam, i.e. pore-pressure, seepage/water leakage, groundwater surface, and deformation. Based on visual observation, there is no anomaly found in dam body during the drawdown. Similarly, instrumentation observations indicate that the dam is normal and there is no anomaly. The pattern of pore water pressure did not change significantly when compared with the previous measurement and the maximum seepage discharge that occurred at + 730 liters per minute. Groundwater is monitored periodically at 10 observation wells, with observations fluctuating according to the water level of the reservoir. Vertical deformation was measured after flushing activity; the maximum deformation was + 0.016 m (below the maximum limit). The sediment flushing in Wlingi reservoir in 2017 restored the reservoir capacity significantly; increasing the effective capacity of 1.37 million m³ to 2.14 million m³.
Year: 2018