Wallace Building Contractors involvement in the Porriua stream flood protection was as the main contractor to the Wellington Regional Council. The work undertaken involved the realignment of the stream and concrete floodwalls through the City Center.
The realignment included building up new stop banks with conditioned fill and placement of Rip Rap Rock to both sides of the wetlands at the mouth of the stream. The concrete floodwalls were constructed to protect the neighboring commercial buildings and had a decorative finish to both sides. The contract also included a large area of landscaping which involved the building of timber walkways over the wetland area and the complete planting of the 2.5-kilometer length of the stream flood protection works.
This contract, completed in 1994 was the biggest workload that Wallace Building Contractors had taken on at the time. The contract was completed on time and within the Council budget. During construction we encountered a 5-year flood and all our temporary works held well. We had temporary walls and bunds along with flow over weirs crossing the stream. This was a major construction project within the Porriua City centre.