Abstract:
Reservoir sedimentation is a major problem for dam safety, water security and
productivity. So, regular monitoring and assessment of sedimentation rate
performances are paramount. Rantambe reservoir with an initial gross capacity of
21 MCM, constructed under Mahaweli Development Scheme is a multipurpose
reservoir used for power generation (52 MW) and flood controlling. However, due
to excess sedimentation through Uma Oya, the capacity of the reservoir is affected
and therefore compromised the dam safety and water security. In this study, the
sedimentation characteristics were assessed using acoustic methods for identifying
the performance of reservoir sediment management measures. Hence, Sub-bottom
profiler with 10 kHz and 3.5 kHz transducers were used as the main acoustic
instrument to determine the height of the water column, the layering of the reservoir
bed and the sedimentation pattern. Results show 1.93 MCM as the reservoir's
existing volume and due to excessive sedimentation in the mouth of Uma Oya
exceeding the dead storage level at the dam thus significantly decreasing the water
depth limiting the reservoir capacity.
Citation:
Yasanga, S.K., Udara, H.M.D., Dilantha, M.G.A., Rupasinghe, M.G.A.R., Premasiri, H.M.R., & Ratnayake, N.P. (2019). Assessment of sedimentation capacity in Rantambe Reservoir using acoustic methods. In D.M.D.O.K. Dissanayake & G.V.I. Samaradivakara (Eds.), Proceedings of International Symposium on Earth Resources Management & Environment 2019 (pp. 61-67). Department of Earth Resources Engineering, University of Moratuwa.