Complex sentence: From 1950 to 1954, though, the Dallas/Garland area suffered from a serious and extended drought, so supplement the water provided by wells, Garland began using the water from the nearby Lake Lavon.
Split into simpler sentences: From 1950 to 1954, the Dallas/Garland area suffered from a serious and extended drought. To supplement the water provided by wells, Garland began using the water from the nearby Lake Lavon.