A River Is Flowing in a Broad, Alluvial Valley and the River

question 127

Multiple Choice

A river is flowing in a broad, alluvial valley and the river is silt- laden but also moves sand and a small amount of gravel. The government decides to build a dam across the valley for power and flood control. What will happen to the river, upstream of the dam?

• A) The river will not change.
• B) The river will start to deposit sand and gravel, frequently spilling out of its channel.
• C) The river will respond to the new temporary base level and cut laterally outside its valley, widening the valley.
• D) The river will downcut.