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.
The Welbedacht Dam is a concrete barrage-type dam on the Caledon River which was designed and constructed by the Department of Water Affairs. The dam has a catchment area of some 15 245 km 2 with a natural MAR of approximately 1210 million m 3 /a (1920 to 1987) and was completed in 1973.Its purpose was to supply water to the city of Bloemfontein via the 115 km long Caledon-Bloemfontein pipeline which has a capacity of ~1.157 m 3 /s.he dam has a catchment area of some 15 245 km 2 with a natural MAR of approximately 1210 million m 3 /a (1920 to 1987) and was completed in 1973. Its purpose was to supply water to the city of Bloemfontein via the 115 km long Caledon-Bloemfontein pipeline which has a capacity of ~1.157 m 3 /s.