Complex sentence: In Wailua Beach, there was one lifeguard rescue that resulted in the swimmer being sent to a local hospital and three other people were swept away at the mouth of the Wailua River, all of whom were quickly rescued.
Split into simpler sentences: In Wailua Beach, there was one lifeguard rescue that resulted in the swimmer being sent to a local hospital. Three other people were swept away at the mouth of the Wailua River, all of whom were quickly rescued.