Depo Provera is considered a very effective method of birth control. If taken every thirteen weeks, it is estimated to be 99% effective. It does not, however, protect a woman from STDs. Studies indicate that women on Depo have a decreased risk of ovarian cancer, Pelvic Inflammatory Disease, and Endometrial Cancer.
The Orinoco is one of the longest rivers in South America at 2,140 kilometres (1,330 mi). Its drainage basin, sometimes called the Orinoquia, covers 880,000 square kilometres (340,000 sq mi), with 76.3 percent of it in Venezuela and the remainder in Colombia.
Over 200 rivers are tributaries to the mighty Orinoco which extends 1290 mi (2150 km) from source to delta. During the rainy season, the river reaches a width of 13 mi (22 km) at San Rafael de Barrancas and a depth of 330 ft (100 m).see map) The most notable fall in this area, at 56 ft (17 m) is Salto Libertador. Navigation, where possible on this part of the river, is by shallow dugout, or canoe. 60 miles (100 km) from the source, the first tributary, the Ugueto, joins the Orinoco.