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.
I you are trying to find X. For the first triangle you want to do “x-9=5” and you should get x=14. For the second one you want to do “x+5=8” and you should get x= 3.
The difference between the two mentioned magnitudes is 4.
A magnitude 1 earth-quack is 10000 times bigger than a magnitude -3 earth-quack. On the other hand, it is 1000000 times stronger in terms of energy release.
Note: To calculate the difference in energy between two earth-quacks, first you calculate the difference between their magnitudes and then you raise 10 to the output you obtain.
The role of religion has steadily declined in recent years.
