Complex sentence: In April 1921, the Municipal Dam, which, approved at a public meeting in 1913, had been delayed through cement shortages, was at last completed, and a picnic for the benefit for all the children followed in the evening by a dance.
Split into simpler sentences: In April 1921, the Municipal Dam, which was approved at a public meeting in 1913 but delayed through cement shortages, was at last completed. A picnic for the benefit for all the children was followed in the evening by a dance.