Live Water Work

Wharemauku Erosion Protection

The contracted works comprises clearing of worksite, excavations, backfilling, supply & placing of Rip Rap, formation of rock riffle and living walls, supply and installation of “Filtrex” Filtersox involved in the realignment and armouring of the Wharemauku Stream.

Earthworks & Associated Works

  • Vegetation removal
  • Strip & stockpile topsoil for reuse
  • Construct temporary access to site and reinstate on completion
  • Excavate to waste

Rock Riffles

  • Excavate 750 deep
  • Place riprap and key in anchor rocks
  • Place & interlock rocks and fill voids with small rocks and fines
  • Stream diverted around works wherever possible. Sometimes work had to be done in the live stream due to confined work areas.

Living Walls

  • Place rock toe and foundation aggregates
  • Place geogrid
  • Fill socks with compost for front of wall and backfill behind

General Comments

  • 1340 tonnes of rock imported and placed
  • Very confined work areas
  • Swamp pads were used for stream crossings
  • Stream crossings were minimised
  • Fencing was done to protect a cabbage tree
  • Kingfisher borrows had to be looked out for and notified
  • Fish passage had to be maintained

Machinery Used

  • Excavators – 20 tonne excavator
  • Dumper – LD1000 Track dumper
  • Trucks – road trucks – carting in rocks

Anzac Cliffs – Anac Park Channel Realignment & Cliff Recontouring and Subdivision

River diversion, alignment and relining in the Manawatu River. Work was necessary to stop the cliff eroding.  An estimate of 20,000m3 was eroding away each year.

Bulk earthworks for new residential subdivision at the top of the cliff.  Construction of stone columns.

River Works

  • 140,000m3 cut to fill – cut diversion channel and excavate gravels to accommodate bed armouring, fill embankment and shape to accommodate rock lining.
  • Completely reshape river channel
  • Transport and place 35,000 tonne of rock lining
  • Construct rock groyne in river
  • Construct access tracks
  • Divert creek


  • 250,000m3 cut to fill
  • 6,500m3 topsoil strip, stockpile and respreads
  • Construct 305 stone columns including supply of stone

Erosion & Sediment Control

  • All controls in accordance with Horizons Regional Council

General Comments

  • Very wet conditions encountered. Used lime stabilisation to complete the earthworks.
  • Working in a large river required careful planning and monitoring of the flow.



Ashurst River Diversion an Bank Repair

Diversion of river channel away from right bank immediately up-river from the Ashhurst bridge.  Works was necessary due to the bank eroding away, along with the carpark.


  • Cut new river channel with the D10 and the excavator
  • Once channel was completed, broke open the top end to let the river through
  • Used the excavated material to rebuild the eroded bank
  • Due to the nature and location of the works, the weather was constantly monitored. Machines were stored well out of the flood path.


  • Cat D10R Bulldozer
  • 50 tonne excavator
  • 2x 40 tonne dump trucks

Contracted directly to Horizons Regional Council.
Works completed to high standard.  Principal happy with the finished product and the amount of communications.