Oct 12 Lecture: Flooding

Question 1

explain how flood control dams work

Answer 1

they retain excess runoff and release it in a controlled manner (so a stream is not overwhelmed).
- they can also provide water for agriculture or hydroelectric power

Question 2

what are some downsides of flood control dams?

Answer 2

• navigation of streams (by animals/ humans) limited
• can cause EQ by their added weight on the rocks
• as velocity decreases rapidly at the dam, waters heavily loaded with sediment will deposit their load (this increases the stage of the dam, could lead to failure)
• sediment free water released by dams can heavily erode downstream

Question 3

Why are tailings dam failures so problematic? Give 2 examples

Answer 3

b/c the water is usually toxic

• athabasca river tailings spill (obed coal mine)
• mount polley

Question 4

ice jams pose a threat for sudden ___ in river levels

Answer 4

increase

up and downstream of the ice jam