Mill Creek Stabilisation 2012

 

Mill Creek Stabilisation 2012

Grant Hood Contracting Limited was contractor for the construction of 840m of bank stabilisation works through 5 sections of Mill Creek.

Scope: 

  • Clearing vegetation, cleaning and reshaping of the streambed and embankments.
  • Stabilising the streambed and embankments using either timber retaining walls, dry packed rocks, gab ion baskets or sandbagging.
  • Erosion and sediment control and management of dry weather and wet weather flows.
  • Landscaping, hard and soft including the supply, planting and maintenance of in excess of 6,500 plants.
  • Working around Listed Protected Trees.

Technical Difficulty:

  • Mill Creek meanders through the residential area of Ashburton.
  • Property boundaries extending to the centreline of the creek. Majority of works on private land. Landscaped creek frontages.
  • Access had to be negotiated and in many instances this limited the size of machinery that could be utilised. Not many people are receptive to 20 tonne excavators tracking across their lawns and gardens.
  • Confined work areas and limited access provided logistical problems. Through some sites the only area available to the contractor was the bed of the creek itself.
  • Clearing and excavation of the bank and bed was generally limited to that length that could be stabilised on the day.
  • Mill Creek forms part of the ADC stock water network so the flow could be disrupted.
  • Works within 10m of Listed Protected Trees.
  • Works in public reserves.
  • Working in waterway, compliance with Resource Consents.
  • Site clearance often revealed the unexpected requiring constant reappraisal of specified methods against alternatives to deliver desired outcomes.

Contract Value $890,000