What is the most logical effect of siltation on lake water storage?

Correct answer: Depth and storage capacity will decrease

The direct answer is C, depth and storage capacity will decrease. Siltation means fine soil and sediment settle on the bottom of a lake. The steps are simple: soil is carried into the lake; it settles on the bed; the bed rises; the water becomes shallower; the space available for storing water becomes smaller. Option C is correct because it states both important effects. Option A is wrong because silt does not always increase storage; it normally fills useful space and reduces it. Option B is wrong because sediment entering a lake does not immediately make salinity zero, and salinity is a different water-quality issue. Option D is wrong because a lake does not become a sea merely because silt accumulates. Remember: siltation means a raised bed, a shallower lake, and reduced storage.