Waiwhetu Stream Remediation Trial, Lower Hutt
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Client: Greater Wellington Regional Council
Sector: Environment
Location: Wellington
Contract Value: $270,000
Completed: Nov 2009
Main Contractor: Brian Perry Civil

 

Waiwhetu Stream has been identified as one of the most contaminated streams in New Zealand.  This trial was the first stage of physical works to determine whether the proposed methodology to remove the contaminated material was viable on a large scale.

Prior to starting work Brian Perry Civil played an active role in risk workshops where risks around flood management and handling of the contaminated material were identified and mitigation measures agreed.

  The physical works included:

  • installation of three sheetpile walls to separate the stream into two cells;
  • over-pumping of the stream and dewatering of the active cell;
  • removal of over 400t of contaminated material to a licensed landfill in covered trucks with sealed trays.

This project attracted a high profile and achieved all expected outcomes.  Brian Perry Civil were also successful in winning the subsequent major project that commenced in July 2009.