What effect can high silt load in a river have on reservoirs?

Correct answer: Reservoir storage capacity may decrease

The direct answer is A: reservoir storage capacity may decrease. Silt is fine soil, sand, and other sediment carried by river water. When the river enters a reservoir, the water becomes slower and loses carrying energy. The sediment then settles on the reservoir floor. Over many years, this accumulation, called siltation, fills part of the space that was meant to hold water. Therefore, the effective or useful storage capacity can fall, and the reservoir may need more management or sediment control. Option A is correct because it describes the direct effect of deposited silt. Option B is wrong because sediment cannot make reservoir depth infinite; it usually raises the bed and reduces available depth. Option C is wrong because silt in a reservoir does not end society’s need for electricity. Option D is wrong because deposited silt does not normally change the river’s source, which is determined by the drainage system and physical geography. Remember: silt settles, storage shrinks.