Complex sentence: The one generous feature of the valley was its water supply; the slightly muddy Jordan River flowed strongly throughout the year in a trough about below the valley floor, fed by numerous clear springs and wadis running into it on either side.
Split into simpler sentences: The one generous feature of the valley was its water supply. The slightly muddy Jordan River flowed strongly throughout the year in a trough about below the valley floor, fed by numerous clear springs and wadis running into it on either side.