Useful Life of Ngancar Reservoir Due to Erosion and Sedimentation
P.T. Juwono1, R. Asmaranto2, A. Murdhianti3

1P.T. Juwono*, Professor of water resources management and engineering Universitas Brawijaya, Malang, Indonesia.
2R. Asmaranto, Associate professor, Department of Water Resources Engineering, Faculty of Engineering, Universitas Brawijaya, Malang, Indonesia.
3A. Murdhianti, Doctoral Program on the Department of Water Resources, Faculty of Engineering, Universitas Brawijaya, Indonesia.

Manuscript received on June 25, 2020. | Revised Manuscript received on June 30, 2020. | Manuscript published on July 30, 2020. | PP: 661-667 | Volume-9 Issue-2, July 2020. | Retrieval Number: B3825079220/2020©BEIESP | DOI: 10.35940/ijrte.B3825.079220
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© The Authors. Blue Eyes Intelligence Engineering and Sciences Publication (BEIESP). This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)

Abstract: Ngancar Dam is located in Ngancar Village, Batuwarno Sub district, Wonogiri Regency Central Java Province. This dam was built in 1944-1946 and is classified as an old dam in Indonesia which has a function to meet the needs of 1300 ha of irrigation water. Ngancar Dam is a type of rock fill dam with a soil core, has a height of 19.40 m above the riverbed and 25.40 m above quarry. The length of the dam peak is 181.00 m and the width is 5.00 m while the reservoir volume at the normal water conditions is 1.64 million m3. Because the Ngancar Dam has been operating for a long time then required the evaluation on the service age of the reservoir due to sedimentation so that it effects on the operating pattern and safety of the dam. Based on the results of hydrological analysis and reservoir bathymetry analysis obtained the information that the reservoir sedimentation rate equal to 4,266.08 m3/year or 11.9 m3/day and this requires mechanical and non-mechanical handling efforts to reduce the sedimentation rate. 
Keywords: Ngancar Dam, erosion rate, sedimentation, sediment delivery ratio.