Complex sentence: Each time a person pulled her, the water pooled around her, rising up so that it seemed she would drown if they let her go, so rescue workers placed a tire around her body to keep her afloat.
Split into simpler sentences: Each time a person pulled her, the water pooled around her, rising up so that it seemed she would drown if they let her go. Rescue workers placed a tire around her body to keep her afloat.