Projects

MAP was proud to partner with Tauranga City Council and Tonkin and Taylor on a multi-stage Early Contractor Involvement (ECI) contract to deliver a vital flood detention structure. This project plays a key role in managing stormwater catchments, reducing flood risk, improving water quality, and supporting future urban development.

The works included construction of the dam structure and the integration of roading and infrastructure to support a proposed subdivision. The site presented significant geotechnical challenges, with much of the area too soft to support heavy machinery. To overcome this, the team engineered a robust access solution using forestry matting and 500mm of imported GAP 150 rock.

To support the outlet structure and pipeline, we installed and drove 153 timber piles, providing additional structural integrity.

We placed 11,000m³ of surcharge pre-load material across the upstream and downstream buttress zones, covering two-thirds of the dam footprint. Settlement was carefully monitored until the required consolidation was achieved, ensuring long-term stability.

Following settlement, the preload was removed to allow excavation of a clay cut-off trench. The dam was then reconstructed to meet modern engineering standards, incorporating filter blankets, geofabric, subsoil drainage, and other critical layers.

The main stormwater pipe system featured a 3.2m diameter PE pipe, with a 1m low-flow PE pipe and breather extending from the intake to the manhole. To ensure durability, sections adjacent to the clay core and the manhole were concrete encased. This phase presented unique challenges, particularly with flotation during concrete encasement, which our team successfully navigated.

Quality was maintained through rigorous testing and surveying. MAP utilised GPS technology to accurately record earthwork levels, drainage inverts, and pipeline alignments. Our innovative approach and close monitoring ensured full compliance and high performance throughout the contract period.

The project was delivered to a high standard, and Tauranga City Council was extremely satisfied with both the process and the final result. This success reflects MAP’s commitment to smart engineering, collaboration, and excellence in execution.