Traditionally, settling basins have been used to exclude suspended sediment in hydropower plants. However, due to the inability of such basins to exclude fine sediment (predominantly hard minerals such as quartz and feldspar) and the excessive sediment loads in Himalayan Rivers, hydro-mechanical equipment and accessories in these plants have been severely damaged. Not only does this involve huge maintenance costs, but there is also a substantial revenue loss due to reduced equipment efficiencies. Thus, more efficient devices such as hydrocyclones are required to remove sediment particles. However, the geometry of a hydrocyclone plays an important role in hydraulic and sediment removal efficiency, and this paper analyses the experimental results of a test rig consisting of a hydrocyclone, 0.38m in diameter, with a modified geometry. The results were compared with those of other investigators, and show that the modified hydrocyclone gives better hydraulic and sediment removal. The implications for suspended sediment exclusion in hydropower plants of Himalayan region are pointed out.