Complex sentence: Warragamba Dam was also a popular picnic spot for Sydneysiders, with up to 3000 people visiting the area on a typical Father's Day, however the dam is now closed to public access.
Split into simpler sentences: Warragamba Dam was also a popular picnic spot for Sydneysiders, with up to 3000 people visiting the area on a typical Father's Day. However, the dam is now closed to public access.