Complex sentence: FERC's plan was to dredge or bypass the sediment while PacifiCorp's plan uses the demolition of the dam to quickly flush as much sediment as possible, thereby minimizing the amount of time the sediment plume harms downstream aquatic life.
Split into simpler sentences: FERC's plan was to dredge or bypass the sediment. While PacifiCorp's plan uses the demolition of the dam to quickly flush as much sediment as possible, thereby minimizing the amount of time the sediment plume harms downstream aquatic life.