Whangaparāoa
Slip Remediation, Stabilisation & Civil Works
Slip remediation and slope stabilisation for 48 Riverhaven, Whangaparāoa - drainage, retaining, and civil works under constrained steep terrain, subcontracting for Fulton Hogan with zero incidents.
We were engaged by Fulton Hogan to provide specialist civil, drainage, and slope stabilisation works after a significant slip on a narrow street in Whangaparāoa. Being subcontracted by New Zealand’s largest civil and roading contractor was a major vote of confidence in our capability and trustworthiness.
Scope & Challenges
- A substantial land slip occurred, threatening the road’s stability, adjacent properties, and existing services.
- The site was extremely constrained: steep slopes, limited working width, minimal allowance for staging or spoil storage, and adjacent vegetation/native bush to protect.
- The street was narrow, so every movement, delivery, machine placement, and crane lift needed exact sequencing, traffic and pedestrian management.
- Ground conditions were variable, likely with wet soil, soft zones, and slope instability risks.
- Safety, environmental protection (erosion control, sediment runoff, interface with native bush), and coordination with Fulton Hogan’s main works and design teams were critical.
Key Deliverables & Solutions
- Capping beam: we worked around a robust capping beam (reinforced concrete) at the toe or critical location of the slip zone to stabilise the slope and tie structures together.
- Drainage & relief works: to prevent further slippage, we installed new drainage, collector pipes, subsoil drainage, and relief drains to lower groundwater pressures.
- Retaining / slope support works: we built cut/fill transitions, batter shaping, slope benches, and anchoring.
- Interface with existing services: we integrated new works with existing water, stormwater, wastewater, and utilities without disrupting them.
- Erosion & sediment control: we put in place mulches, silt fences, geotextiles, clean water diversion, temporary earthworks sequencing to protect the environment/bush edge.
- Traffic, access & staging: we developed a complex traffic management plan, temporary works zones, safe pedestrian egress, and carefully scheduled deliveries to avoid congestion.
- Health & Safety: worked under Fulton Hogan’s SSMP (Site Safety & Management Plan), carrying out hazard identification, daily briefings, risk assessments, exclusion zones, and ensuring zero incidents throughout. Our safety record here underscores our reliability under pressure.
Outcomes & Highlights
- The slip zone was stabilised fully, ensuring long-term road safety and protecting adjacent land.
- All works were completed without any safety incidents - an achievement given the steep slopes, confined space, and high-risk nature of the job.
- The remediation and civil works completed in close coordination with Fulton Hogan’s broader project allowed seamless continuation for the main contract.
- Our successful delivery on this high-risk, high-visibility subcontract positions us strongly for similar slip / remediation / urban stabilisation projects going forward.