Author(s): D. L. Maskey; N. R"Uther

Linked Author(s): Diwash Lal Maskey

Keywords: Run-of-River hydropower projects; Intakes; Sediment buildup; Numerical hydraulic modelling

Abstract: In a Run-of-River (ROR) hydropower project with a low height diversion structure, sediment build-up in front of a side intake and removal of deposit are always a challenge. The design of sluice gates and intake layout is based on subjective expert knowledge and always involves rigorous discussion. The layout and design are popularly investigated and optimized through physical hydraulic model tests, but fine sediment transport cannot be modelled due to scaling issues. Numerical 3D hydraulic models are developed to cope with this and are gaining increased attentions due to high speed and low costs. This paper presents the utilization of a numerical hydraulic model for study of an intake layout considering the sediment transport. A case study of design of headworks of Kabeli-A Hydroelectric Project in Nepal is presented. Physical hydraulic modelling of the headworks was conducted to select an alternative solution and to optimize the design of intake layout for efficient handling of sediment buildup at the front of the intake. The investigation only conducted modelling of bed load transport and effects of the suspended sediments were assumed. The sediment transport modelling in front of the intake was performed using a 3D RANS model coupled with a sediment transport module. Three alternative layouts of intake were studied. The fine sediment build-up is modelled successfully, providing the duration for the bed to reach the intake invert and the sediment concentration passing through the intake. The results of the numerical model were found to be similar with the results of the physical model investigations. It is concluded that a numerical model can be used to study and select a best layout of intakes for efficient handling of fine sediments.

DOI: https://doi.org/10.14264/uql.2020.611

Year: 2020