Complex sentence: Roughly 1/2 of the creek's length runs through a reservoir preserve owned by Orange County, NY, this preserve status is credited with maintaining the upper creek's floodplain in its natural state for over one century.
Split into simpler sentences: Roughly 1/2 of the creek's length runs through a reservoir preserve owned by Orange County. This preserve status is credited with maintaining the upper creek's floodplain in its natural state for over one century.