Channel opening good, but in the wrong place

The Entrance Channel was opened pre-emptively by Central Coast Council in Feb 2022.

Many thanks to the Central Coast Council for opening The Entrance channel during the recent flood event.

It certainly helped as the water was not as high as it could have been with all that rain.

A qualified hydrologist colleague, however, noted the opening was in the incorrect spot – the widening of the south end of the entrance channel can only ever be shallow, due to the underlying bedrock there.

This also partially explained why the water took time to drain this flood.

Next time, next year, it would be much more effective to excavate a straight east-west channel just south of the Little Tern area – about 10m wide.

This is where depth and fast flow can be obtained as the water can exit under pressure there and take more volume – and work even in high/king tides and strong waves. 

To the south, the channel naturally curves, slows down, deposits sand and is not as effective.

Guy McKanna, Chittaway

2 Comments on "Channel opening good, but in the wrong place"

  1. Campbell Black | March 13, 2022 at 3:29 pm |

    It was good to see Council being proactive in dealing with the impending flooding coming our way at The Entrance channel.The gallery was lined every day with onlookers watching repeated efforts at opening new canals and reactions were both mirth and anger.
    The main question asked is why a large bulldozer wasnt used from the outset scraping the area they were working on down to a foot or so above the waterline about 200 t0 300metres wide so that the rising flood would have a large area to spill into the ocean.
    The surplus sand could have been just left there for Mother Nature to deal with. Who knows she may even throw a bit back on our beaches.
    Instead of a week this would have only a day or so and leave Council workers to do more important jobs like clearing blocked drains.

  2. Steve Middendorf | March 16, 2022 at 5:39 pm |

    It was good to see Council out there proactively widening the channel. The “what is” seems to change in the telling. At least the diggers were there, ahead of time to work with what we had on the day. I’m in favour of doing some experimenting with the opening. But we must keep in mind that mother nature can throw something new out us at any time. Council can’t be blamed for that, only for inaction.

Comments are closed.