Question

Hoover Dam is the largest dam in the United States, built on the Colorado River to supply hydroelectric power and flood control. Which of the following best describes a downstream environmental effect of Hoover Dam on the Colorado River watershed?

The damming of the Colorado River led to a change in stream flow, preventing river water and sediments from reaching the delta area.

Answer 1

The best description of a downstream environmental effect of Hoover Dam on the Colorado River watershed is that the damming of the Colorado River led to a change in stream flow, preventing river water and sediments from reaching the delta area. This is because the dam blocks the flow of water and captures sediment, which would have continued downstream and been deposited in the delta area to create rich soil and support aquatic and bird life. Without the regular input of fresh water and sediment, the delta area has become increasingly dry and barren, impacting the local ecosystem and economy.

Answer 2

Hoover Dam's environmental effect on the Colorado River watershed includes a change in stream flow, preventing water and sediments from reaching the delta area.

Step-by-step explanation:

A downstream environmental effect of Hoover Dam on the Colorado River watershed is a change in stream flow, which prevents river water and sediments from reaching the delta area.

Before the construction of Hoover Dam, the Colorado River would flow freely through the river channel and deliver water and sediment to the delta, which is a critical ecological area. However, with the dam in place, the flow of the river is regulated, and a significant portion of the water and sediments is captured and stored in Lake Mead, the reservoir created by the dam.

This reduction in stream flow and the lack of sediment deposition has led to a decline in the size and health of the delta, impacting the local ecosystems and wildlife that depend on it.