Complex sentence: On 1 March 2002, the spring was closed temporarily for two months to facilitate some improvements works when the area around the spring had become sodden and muddy, and litter had become a problem because of the large numbers of visitors who flocked to the hot spring.
Split into simpler sentences: On 1 March 2002, the spring was closed for two months while improvement works were carried out to the area around the spring, which had become sodden and muddy. Litter had also become a problem because of the large numbers of visitors who flocked to the hot spring.