Which statement describes the effect of sediment buildup on reservoir operations?

• A. It increases storage capacity.
• B. It has no effect on reservoir operations.
• C. It reduces storage capacity and degrades water quality.
• D. It improves water quality.

Answer: (C)

Sediment buildup in a reservoir reduces the volume available for storage and often degrades water quality. When sediments from the watershed settle in the reservoir, they occupy space that used to hold clear water, shrinking the active storage available for supply, drought relief, irrigation, and flood control. Over time, the deposited layer raises the bottom, farther reducing usable depth and limiting the reservoir’s ability to store water during dry periods or to cushion floods. The settled sediments also increase turbidity and suspended solids, which cloud the water, can release nutrients and contaminants, and often lead to taste, odor, or color problems. These changes complicate operations and may require dredging or sediment management to maintain storage and release targets. The statement that sediment has no effect, or that it increases storage capacity or improves water quality, does not align with how sedimentation impacts reservoirs.