Complex sentence: Due to siltation, the width of the sand bar has fluctuated with the mouth getting choked and the spit of the lake continually changing; the location of the mouth has also frequently shifted, generally towards the northeast.
Split into simpler sentences: Due to siltation, the width of the barrier has fluctuated and the mouth to the sea has periodically been closed. The location of the mouth has also frequently shifted, generally towards the northeast.