geography

How can Highway 857 potentially affect flooding in Hickory Estates?

The road could block floodwaters and cause the river to flow south.

Because of the impermeable road surface, both Route 857 and Route 342 would cause floodwaters to be potentially trapped in Hickory Estates, causing flooding.

The road would have no effect; flooding is not affected by urbanization.

The bridge across the river could block water flow, causing higher water levels and increasing the potential for flooding.

Stream gradient is calculated as the change in elevation (measured in feet) divided by the distance traveled (in miles). Using the base flood elevation lines, what is the stream gradient of the main trunk of Clearwater River shown on the map?

approximately 3 feet/mile

approximately .5 feet/mile

approximately 10 feet/mile

approximately 15 feet/mile

According to the map, how many total buildings in Hazard City are at a high risk for flooding during a 100-year storm event?

0

3

13

more than 20

If the Palouse River is dammed upstream, how might this affect future flooding in Ralston?

It would have no effect.

It would raise Clearwater River, increasing the amount of water in its tributary, and increase the risk in Ralston.

It could lower Clearwater River, decreasing the amount of water in its tributary, but this would have no effect on Ralston.

It could lower Clearwater River, decreasing the amount of water in its tributary, and decrease the risk in Ralston.

Paleo-flood (ancient flood) deposits have been found in parts of Ralston that are currently in Zone C. Which of these answers provides a possible explanation for this finding?

The flood map is drawn incorrectly.

The river system experienced a flood greater than the 500-year flood.

The river was previously located closer to Ralston and has moved.

All of these are possible explanations.

You are buying a home in Ralston, located in Zone B with no previous flooding. The home costs $250,000 and has no basement. How much should you expect your flood insurance rate to be?

$773.50/year

$221/year

$441/year

$552.50/year

A flood greater than the 500-year flood travels through Hazard City. Which side of the river would be safest to live on?

They will both be equally affected.

north

south

It is impossible to tell.

A new housing development is being built upstream. How might this affect flooding in Hazard City?

It would have no effect.

Development can cause more water runoff into a stream and increase the potential for flooding.

Development can cause more water runoff into a stream and decrease the potential for flooding.

Development allows water to soak into the ground faster and decreases the potential for flooding downstream.