Canaipa Passage Maintenance Dredging 2014

Channel Maintenance and Beach Nourishment

Principal: Gold Coast Waterways Authority

Location: Canaipa Passage, Gold Coast

Contract Value: $480,000

Completion Date: May 2014

Canaipa Passage is a 13 kilometre secondary navigation channel between North Stradbroke Island and Russell Island in southern Moreton Bay. The channel is heavily used by a variety of recreational and commercial vessels particularly during school holidays as the calm waters offer protection to yachties and anglers in addition to campers making their way to and from the increasingly popular Slipping Sands.

Scope of Work

The Gold Coast Waterways Authority have nominated two areas to be dredged to a depth of 2.5m below LAT (maximum depth of 2.8m below LAT). The total material that was dredged is approximately 34,000m3.

The southern dredge area involved the slight realignment of the crossover channel to align better with the natural seabed contours. Almost 25,000m3 was pumped from this area and transported only 500m to the nourishment area. The northern dredge area required the removal of only 10,000m3 of material, but this material had to be transported almost 2,000m to the nourishment.

The dredged sand was used to nourish the eroded beaches in front of the fishing huts and along the beach in front of the Slipping Sands on the western side of North Stradbroke Island.

Innovations

  • Use of discharge barge to place material along the beach at slipping sands
  • Adaption of an anchor barge with a three point anchoring system to manoeuvre the discharge pontoon along the beach at Slipping Sands

Challenges

  • Pumping the material up to 2,000m at a reduced production rate from the northern dredge area
  • Spreading the material evenly along the beach at the nourishment
  • Maintaining safe navigational access for all boating traffic in this very popular and busy recreational waterway.