Complex sentence: Once the largest body of water in the city, almost the entire creek today is covered by landfill and converted to an underground culvert and a storm drain, with remnants of the creek flowing at both Glen Canyon Park San Francisco Recreation and Parks Department.
Split into simpler sentences: Once the largest body of water in the city, the entire waterbody today was reclaimed and the creek itself was converted to an underground culvert and a storm drain. Remnants of the original creek still exist today, and can be found flowing at both Glen Canyon Park San Francisco Recreation and Parks Department.