Author Question: Why is living on a floodplain behind a levee safe from flooding? a. Levees are rarely overtopped. ... (Read 53 times)

abern · **on:** Jul 13, 2018

Why is living on a floodplain behind a levee safe from flooding?
a. Levees are rarely overtopped.
b. Water cannot seep under levees to flood the floodplain.
c. Levee banks are rarely eroded enough to fail.
d. Once a levee is built high enough to contain a 100-year flood, it will never flood.
e. Actually, 100-year flood levels often continue to get higher with time.

Question 2

How does a bridge promote erosion in a channel?
a. The bridge pilings interfere with the water flow, causing additional sediments to be deposited.
b. The water velocity decreases, due to restricted flow over the floodplain.
c. The water velocity increases, due to restricted flow over the floodplain.
d. The channel height decreases, and large particles fall out, creating more surfaces for erosion to occur.
e. A bridge does not promote erosion.