Complex sentence: This increased the maximum flow along the flume to Roslyn Lake from about to about and, since the combined flow entered the lower Bull Run River after leaving the powerhouse, the system altered the flows of three rivers.
Split into simpler sentences: This increased the maximum flow along the flume to Roslyn Lake from about to about. Since the combined flow entered the lower Bull Run River after leaving the powerhouse, the system altered the flows of three rivers.