New River Mouth Silts Over - Closes

Overnight on the first night of creating the Duke's Head Channel, the "mouth" has silted over.  This was caused by a combination of the overnight high tide and big swell pushing sand up onto the beach, and the sides of the channel collapsing and the sand falling in and not being swept away.  There is now a lot of conjecture about whether or not it will work. The trench digger is back in action.   It seems to me the channel has been cut too obliquely from the river to the sea.  You will see from photos below (the last two) that the channel comes in at a right angle off the river.  This doesn't seem natural, nor how rivers are naturally shaped.  Also there is bedrock about the first third of the way in, thus limiting the depth and the amount of water gushing through the channel (that is when it is able to).  Obviously the stronger it gushes the greater the chance of establishing a permanent mouth.  In summer the river level may well be lower than this bedrock.  If so then the river will be unable to follow the present channel course.  It will need to change shape before then.     I spoke to the operators of the trench digger and they said that with persistence it will work.  But maybe the money will run out by then.  (The Shire is not noted for its largess, especially to things Augusta.)  These people also thought the channel should have been cut further to the east (where Trevor Price says there is no bedrock).  Price thinks it could work if the course changes direction naturally to get away from the bedrock. You can easily sense his disappointment and frustration at the moment.  He is the river's only professional fisherman and he knows it like the back of his hand.  Surprisingly, no-one sought his advice about where the cut should go. If it was up to me, I would cut my losses and start again, this time coming in more of a straight line off the river and directly through the dunes to the east of the present position. This is where Price would have suggested it to go.    I hope the new channel works, and it can work, but I don't think the configuration of the channel is right.  I don't feel optomistic at the moment.  Time will tell.

Blackwood River mouth

Well folks, here it is....the new Blackwood River mouth, born at 7am Wednesday 18 August 2010.  The trench digger is still in place as there is a low tide at 4pm and it will then scoop out some more sand at the beach-head.  Dukes Head channel is only a meter or two deep as they struck bed-rock.  According to the local professional fisherman Trevor Price if they had made the channel 100m to the east this would not have happened.  He expects the existing river mouth which is a good km further east, to now close over fairly soon.  This will help to better establish the new channel.   Trevor is pictured right with his father Colin, who with his father Norman and another man, crated the famous river mouth in 1945 using a horse and scoop.  He has lived to see history repeated.  Well done Colin!

Blackwood River-mouth progress

These photos were taken at 10am Tues 17 August 2010. Much progress has been made since last Saturday with a 2m deep channel now extending from the river to the beach just short of the waters' edge.  The cut does not take the shortest distance from the river to the sea, but is angled to reach the sea at the surfing beach in front of the Lions Look-out.  Some concern has been expressed about this because this is where the greatest wave action occurs due to the sand bank that exists here.  It gives the best braking wave for the surfers.

The concern is that because of the sand bank in this part of the beach, and the wave action it causes, that the new river-mouth will soon silt up again.
Lets hope not.









This is a photo of me fishing in the dinghy with Jason and Ashley which was published in the Western Fisheries magazine a couple of years ago. The last photo is just a bit of bragging!

          

Blackwood River

Work started this weekend (14-15 August 2010) to create a new mouth of the Blackwood River.  It is expected that this will increase the tidal flow of sea water into the Hardy Estuary, thereby eliminating outbreaks of algal bloom that are adversely affecting the estuary.