The flow of the river is such that during flood it dumps a large amount of sand at its mouth. This is normally swept out to sea through the river mouth but as the flood stage receeds the river has less and less energy to flush-out its channel. Instead the sand accumulates as a river mouth bar which blocks the mouth of the river until the next flood stage or until a storm removes it seawards. The river continues to flow but the water gets to the sea by percolating through the permeable sand bar. The river is said to be blind.