Line segments have two end points
rays only have one end point
The U.S. has more than 87,000 dams greater than six feet high (and two million overall). While many dams continue to provide benefits such as flood control, irrigation, and water supply, for other dams the cost of maintenance or the negative effects on communities, fish, and tribes justifies their removal.
Dam owners and regulators decide whether to remove a dam by weighing many factors including: the cost of removal and the ability to replace any lost power generation against avoided long-term maintenance; safety concerns; benefits to endangered fish populations; increased recreational and commercial fishing; and restoration of cultural values of nearby tribes.
By 2020, roughly 70% of dams will be more than 50 years old, inviting us to reconsider the value to the public of long-term investments in this infrastructure.
Answer:
The stream will flow fastest between 2 and 3.
Explanation:
On this map, we can see two basic elements, one being the contour lines, and the other being the color with which a stream is presented. The contour lines are giving us a good representation of the relief and where it is steeper and where it is less steep. Basically, where the contour lines are closer to each other, we have a steeper relief, and when the contour lines are further away, the relief is less steep.
The water moves under the influence of gravity, so downward. Where the steepness is the greatest, the gravity influences it the most, so it moves faster, while where the steepness is smaller, the gravity influences it less, so it moves slower. On this map, the contour lines are closest to each other between points 2 and 3, meaning it is the steepest part of the relief, and it is the place where the stream flows the fastest.
