The Black Death was a plague the spread across medieval Europe in 590CE to 1500CE. It was an infection caused by rats and then spread by fleas. The rats were carrying a lot of germs and bacteria at the time so a flea would bite the rat and then would and bite a person.
The average life expectancy of a dam is 50 years, and 25% of the dams in the Army Corps of Engineers National Inventory of Dams are now more than 50 years old.This number is projected to increase to 85% by the year 2020.he Glen Canyon Dam supplies over 5 million people with power (Glen Canyon Dam Adaptive Management Program, 2007). These two dams also have the capacity to store 32,471,000 acre-feet and 27,000,000 acre-feet of water, respectively. In order to harvest hydropower however, dams must be built.
1 Gordon below Franklin Dam â 105 metres (344 ft) high, at 42Â°35â²2â³S 145Â°43â²55â³Eï»¿ / ï»¿42.58389Â°S 145.73194Â°Eï»¿ / -42.58389; 145.73194 - accessed via the Gordon River from Strahan. 2  This was the lowest point on the river possible for a dam, since the tidal zone extends to Big Eddy, just 1 kilometre (0.62 mi) downstream. This was the lowest point on the river possible for a dam, since the tidal zone extends to Big Eddy, just 1 kilometre (0.62 mi) downstream. 2  Dam #2 â 200 metres (660 ft) high, at 42Â°22â²34â³S 145Â°45â²25â³Eï»¿ / ï»¿42.37611Â°S 145.75694Â°Eï»¿ / -42.37611; 145.75694, accessed by the Mount McCall Track (Franklin River Road).