Karnali dam (Nepal)

Sediment management on a new dam

Client: GMR Upper Karnali Hydropower Ltd - Model scale: 1/100


The GMR Consortium is in charge of building the Upper Karnali hydropower scheme in Nepal (900 MW).

One of the biggest technical challenges concerns managing sediment inflow into the dam reservoir (suspended and bed-load).

Description of the physical scale model

The model represents:

  • A 3 km section of the reservoir,
  • The flood spillway, the hydropower water intakes and the diversion tunnel. All these components are adjustable.
  • The flood hydrographs (water and sediment),
  • The sediment transported by the river, either suspended or as bed-load.

Aims of the physical scale model

The main purpose of the scale model is to:

  • Study the hydraulic behaviour of the structures and the reservoir (currents, spillway capacity, vortex formation on the suction side),
  • Study various solutions to prevent reservoir siltation as a result of bed-load transport,
  • Propose solutions to prevent suspended matter being drawn into the water intake (abrasive effect on the turbines).