Reservoir sedimentation causes storage loss, reducing usable storage capacity and rendering the reservoir inefficient for the function for which it was designed. This is becoming more intense as the catchment's sediment supply increases as a result of numerous development activities and the effects of climate change. As a result, several countermeasures must be implemented to manage the sediment. Diversion tunnels, also known as sediment bypass tunnels, are an effective way to slow the process of reservoir sedimentation. The sediment accumulation of both bed load and suspended load is greatly reduced by channelling material around the reservoir into the downstream. A diversion tunnel is also important in the case of hydropower projects in the Himalayan region, where reservoirs have a high suspended sediment load. If not addressed, suspended silt enters the water conductor system via power intakes, causing severe damage to turbines and other power house equipment. This paper emphasizes the practicality of diversion tunnels (sediment bypass tunnels), particularly in the case of hydropower plants.