Complex sentence: During the wet season here starting in December, water levels can rise some 25 to 40 feet although water levels have been strongly affected by the building of the controversial Balbina Dam on the river in the nid to late 1980s to generate electricity.
Split into simpler sentences: During the wet season starting in December, water levels can rise some 25 to 40 feet. Water levels have been strongly affected by the building of the controversial Balbina Dam on the river in the mid to late 1980s to generate electricity.