Complex sentence: It was reconstructed and expanded in 1952 to include a network of marshes bordering the Seret River when there was a massive rebuilding of Ternopil-and when it was decided to transfer the water resources of all local authorities in 1956, they began to recover Ternopil pond.
Split into simpler sentences: It was reconstructed and expanded in 1952 to include a network of marshes bordering the Seret River during the massive rebuilding of Ternopil. At that time, it was decided to transfer the water resources to the local authorities in 1956, which began to recover the Ternopil pond.