Complex sentence: A new design was underway by 1971, which was approved in 1975; however, environmental groups filed lawsuits to stop construction, and the controversy continued even when construction finally resumed in 1981.
Split into simpler sentences: A new design was underway by 1971, which was approved in 1975. However, environmental groups filed lawsuits to stop construction and the controversy continued even when construction finally resumed in 1981.