A catchment area of 125 km? is contributing MAR of 25*105 m to a proposed reservoir having a length of 4.5 km and average storage capacity of 8*10 m. The erosion potential of the reservoir catchment varies from low (30% of area), medium (45% of area). and high (25% of area). The catchment is situated in Sediment Region 4 (Table 4). Determine the total storage volume required by taking the effect of sedimentation for a 30-year design life into consideration by using the methods as proposed by Churchill and Brune. The trap efficiency of the reservoir could be assumed as 98% (Churchill) and 92% (Brune) respectively. [10] Table 4: Factors for converting standardised average sediment yield to site-specific sediment yield Standardised average yield Sediment potential factors Region (Ukm/year) FH Fu FL 49 2.23 1.00 0.92 2 N/A N/A N/A N/A 3 82 1.87 1.00 0.35 4 155 1.44 1.00 0.18 30 2.69 1.00 N/A 6 335 1.00 1.00 N/A 7 203 N/A N/A 1.00 8 35 1.00 1.00 0.23 185 1.00 1.00 N/A