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: Most submarines use sonar as a navigation aid. How would sonar enable an underwater vessel to move through the ocean depths? It would enable an underwater vessel to move through the ocean depths because it would tell the navigator how far away they are from the bottom, and if they are too close or too far.
Oceanographers study the ocean through sonar and submersibles. Oceanographers use sound waves(sonar) to find the location of objects or to communicate. The sound waves travel to the ocean floor then back, and oceanographers count how long it takes to find how deep the ocean is at that location. Oceanographers use that to make maps and profiles of the ocean floor. Oceanographers use submersibles to study the ocean depths. Submersibles help oceanographers make discoveries about the deep ocean.
Explanation:
It would have to be Brazil
Explanation:
Verkhoyansk Mountains, also spelled Verkhoiansk or Verchojansk, Russian Verkhoyansky Khrebet, mountains of Sakha (Yakutiya), far northeastern Russia, extending for 700 miles (1,100 km)—in a huge arc parallel to and east of the lower Lena River—to the Laptev Sea.
