If you're going to be in the St. George area in late March-early April then make a plan to visit Gunlock State Park to see the seasonal waterfalls flowing. The waterfalls flow when Gunlock Reservoir overflows, which typically happens after spring runoff starts.

You have to pay to park at Gunlock State Park. It costs $10 for Utah residents and $15 for out-of-state vehicles. The park is open from 7am-10pm daily. Get there early if you're going to see the watefalls, because it can get crowded!