Complex sentence: Local springs were used to form a boating lake in the park, but frequent drying up problems led to the lake being filled in and the river was culverted in 1967; however, in 2012, the Wandle was restored to the surface in Wandle Park.
Split into simpler sentences: Local springs were used to form a boating lake in the park, but frequent drying up problems led to the lake being filled in and the river was culverted in 1967. In 2012, the Wandle was restored to the surface in Wandle Park.