How do flood control structures work?

What defines a watershed?

• A specific area of land where all water flows into a single ocean.

• The entire area of land where precipitation collects and drains into a common outlet.

• A network of underground pipes that collect rainwater.

• The highest point of land that separates two river systems.

How do small and large watersheds typically respond to rainfall events?

• Small watersheds flood during widespread, sustained wet weather, while large watersheds flood during single intense storms.

• Both small and large watersheds flood only during single intense storm events.

• Small watersheds flood during single intense storm events, while large watersheds flood in response to widespread, sustained wet weather.

• Neither small nor large watersheds are significantly affected by rainfall, only by snowmelt.

What is the consequence when a river channel "overbanks"?

• The river's flow rate decreases significantly.

• The river's water level drops, exposing more of the riverbed.

• A small rise in the river's level leads to a much wider area of inundation.

• The river's banks become steeper, confining the water more effectively.

What is the primary function of levees in flood control?

• To increase the natural flow rate of a river.

• To divert floodwaters to undeveloped areas.

• To confine rivers within artificial banks, protecting adjacent areas.

• To create new channels for navigation during floods.

What is the main purpose of diversion canals in flood management?

• To create new recreational waterways for boats.

• To increase the amount of water available for irrigation.

• To divert floodwaters to undeveloped areas, reducing damage to populated regions.

• To improve the aesthetic appeal of urban riverfronts.

What is the primary function of dams specifically designed for flood control?

• Generate hydroelectric power

• Provide water for irrigation

• Store excess water during floods for gradual release

• Create recreational lakes

What is a potential negative consequence when a reservoir, primarily used for water supply or hydropower, is already full during a major flood event?

• The dam will automatically generate more electricity.

• The excess water will be safely stored for future use.

• Floodgates may need to be opened, potentially causing or worsening downstream flooding.

• The reservoir will simply overflow without impact.

How do multi-purpose dams typically manage competing demands for water use and flood control?

• They are designed to prioritize only one function at a time.

• They use separate, independent dams for each specific purpose.

• They establish different "pools" or zones within the reservoir for various uses, such as conservation and flood storage.

• They rely on advanced technology to instantly convert water from one use to another.

Why is the term "flood risk management" increasingly preferred over "flood control" by engineers and hydrologists?

• "Flood control" is an outdated term with no practical meaning.

• It emphasizes the complete elimination of all flood events.

• It acknowledges the inherent limitations in fully controlling natural phenomena and focuses on mitigating potential impacts.

• It suggests that floods are always beneficial and should not be controlled.

Which of the following is an example of a flood risk management strategy that focuses on increasing resiliency and reducing the consequences of flooding, rather than solely preventing it?

• Constructing higher and stronger levees along riverbanks.

• Building more dams to hold back larger volumes of water.

• Converting floodplains into natural wetlands, parks, or trails.

• Implementing cloud seeding to reduce rainfall during storm events.