Response

What are some of the drawbacks to building Flood-Control Dams? Explain how reservoir behind a dam can lower its own capacity for storage and ultimately greatly reduces its effectiveness.

While Flood-Control Dams were built to lessen the catastrophic effect of floods, building these structures also has significant costs and consequences. (Lutgens & Tarbuck, 2011, pg 93) Flood-Control Dams spread the flooding in large areas gradually at the expense of land. The dams also block sediment from passing through. Flood-Control Dams can even fail.

Reservoirs created by dams may cover historic sites and scenic valleys. (Lutgens & Tarbuck, 2011, pg 93) Although the dams prevent flooding from happening the water is released slowly on to the land, it can overflow farmland, making it impossible to grow anymore. The water can fill into the forest killing some of the wildlife.

When the dam block the sediment from flowing through it builds up at the bottom leaving less room for the flood water to occupy. This creates less storage space for the flood water and decreases the effectiveness of the dam more as more sediment builds. Now more water is flowing over and at a much faster rate that was expected.

Everything man made can fail, such as dams. When a dam breaks the water is suddenly released at a rapid pace, over flowing the reservoir behind it. Land that was people once occupied to live has now been flooded. Everything that the dam was built to prevent will happen.

Lutgens, F.K. & Tarbuck, E.J. (2011) Foundations of Earth Science (6th ed). Upper Saddle River, NJ: Prentice Hall