The development of sediment bypass channel for sediment management in the Brantas River Basin, Indonesia

Abstract

Wlingi and Lodoyo reservoirs are major reservoirs on the mainstream of the Brantas River. Both reservoirs have problem on severe sedimentation due to eruption of Mount Kelud, one of the most active volcanoes in Indonesia. Countermeasures such as sediment bypassing, flushing are conducted to encounter the sedimentation in Wlingi and Lodoyo. Construction of sediment bypass channel is a long term countermeasure to prevent the lahar sediment inflow from entering Wlingi reservoir after eruption of Mount Kelud. To prevent the Putih River's lahar sediment from entering Wlingi reservoir, the sedimentladen flow of the Putih River was diverted to the Siwalan River by bypass channel of about 3.2 km length completed in 1991. The bypass channel reduced sedimentation in Wlingi reservoir but shifted it downstream to Lodoyo reservoir. An extension of the bypass channel from the Siwalan River to the Brantas River downstream of Lodoyo dam was completed in 2011. The completed bypass channel and lower extension is 7.2 km long. In the future, the extension of bypass channel to divert sediment from the Lekso and Jari River in the upstream of Wlingi reservoir needs to be developed. This paper will discuss the development of bypass channel in the Brantas River basin to manage sediment in the basin general and to promote sustainable use of Wlingi and Lodoyo reservoirs in particular.