Another section of the seawall undermined and lost.
Paekakariki beach is known for its volatility and overnight change in beach sand levels. When a large amount of sand is shifted by unusual tides from one area to another inevitably the depth of wall foundations become critical. If the sand level erodes lower than the wall then the material behind the wall is washed out by the inherent volatile wave action. This causes a cavity to form behind the wall as the backing material falls into the turbulence. From that time on the wall’s survival is dependent on the strength of the timbers which take the full force and weight of the waves. Loud cracking of beams and snapping of poles can be heard above the sound of the incoming surf.
One may ask – why don’t the workers pour a bit of course, fast drying, concrete between tides into the cavity at the bottom behind the threatened wall when it is undermined by the sea. And THEN replace the lost backfill. The concrete would block off the bottom penetration of the surf and stop replacement fill being lost to the next tide. The wall is destroyed when there is no back fill to support it.
Boulders stockpiled by the council in the event of storm caused wall failure are poured by contractors into the gap left by the destroyed wall. Never mind, one might say, – Some of the boulders may be used for building the second tier of the proposed new wall which will offset a bit of the cost. But maybe not so because those proposed boulders are designed to be of larger size in order not to be dislodged by future wave violence.
When large earthmoving trucks and excavators are employed in a seemingly desperate environment, the potential for large waste of council funds escalates.
Some years ago during a situation I gained council permission to pour concrete into that opened up space. I decided to nip away for a couple of minutes to get a length of reinforcing steel to place in the concrete yet to be poured. And during that time a truck tipped replacement material into the hole spoiling the fix. And of course the wall was destroyed later that week.
Will they ever learn?
The beach level measured from the top of the wall at this point was 3.1 meters
Concrete extension fully undermined and exposed
Bit of a mess
Outfall flumes wiped out
Disappearing back fill
Wall in danger