Complex sentence: Additional rain events in June and September each moved the lake overcapacity again by less than, and the water levels eventually dropped below the spillway on December 5,2010, the last time Lake Stamford was full.
Split into simpler sentences: Additional rain events in June and September each moved the lake overcapacity again by less than. Water levels eventually dropped below the spillway on December 5,2010, the last time Lake Stamford was full.