Complex sentence: Through the City of Cambridge's exclusive municipal water system, the city further controls two exclave areas, one being Payson Park Reservoir and Gatehouse, a 2009 listed American Water Landmark located roughly one mile west of Fresh Pond and surrounded by the town of Belmont.
Split into simpler sentences: Through the city of Cambridge's exclusive municipal water system, the city further controls two exclave areas. One being Payson Park Reservoir & Gatehouse, a 2009 listed American Water Landmark located roughly 1 mile west of Fresh Pond which is surrounded by the town of Belmont.