Floodplains & Flood Control Quiz

Floodplains & Flood Control Quiz

Dams, levees, flood risks (10 questions).

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Floodplains & Flood Control Quiz: Quick Study Notes

Floodplains act as natural buffers and fertile agricultural grounds, yet they present significant hazards to human settlements. This section reviews key concepts regarding river dynamics, protective infrastructure like dams and levees, and the statistical analysis of flood risks used by planners.

Dams

Barriers built across rivers to store water, regulate flow, and generate power, often creating an upstream reservoir.

Levees

Natural or artificial embankments running parallel to a river channel designed to prevent water from spilling over the banks.

100-Year Flood

A statistical probability indicating a flood event has a 1% chance of occurring in any single given year, not a frequency guarantee.

Alluvium

Loose, fertile soil or sediment (clay, silt, sand) that has been eroded, reshaped by water, and redeposited in a non-marine setting.

Key Takeaways

  • Floodplains form through the erosion of riverbanks and the deposition of nutrient-rich sediments.
  • Urbanization tends to increase flood risk by replacing absorbent soil with impermeable surfaces like asphalt.
  • While dams control floods and provide power, they disrupt sediment transport and aquatic migration.
  • Levees can fail catastrophically via overtopping or breaching during extreme weather events.
  • Non-structural controls like zoning laws restrict building in high-risk zones to minimize damage.

Frequently Asked Questions

What is a floodplain?

A floodplain is an area of low-lying ground adjacent to a river, formed mainly of river sediments and subject to flooding.

How do levees function?

Levees work by artificially raising the height of riverbanks, confining the flow of the river to its channel during high water events.

What is the difference between a dam and a levee?

A dam runs perpendicular to the river flow to stop or impound water, whereas a levee runs parallel to the river to contain it.

Why are floodplains often used for agriculture?

They contain alluvium, a nutrient-rich sediment deposited by floodwaters that makes the soil exceptionally fertile for farming.

What causes a flash flood?

Flash floods are caused by heavy or excessive rainfall in a short period of time, often on saturated soil or impermeable urban surfaces.

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