By Robyn Edwards, Tonkin + Taylor Ltd
Contaminated land and groundwater remediation projects are inherently complex, requiring technical and scientific expertise, careful navigation of evolving regulatory frameworks, and a commitment to social responsibility. Yet, while significant focus is often placed on the technical aspects of contamination assessment and remedial technologies, one key factor consistently underpins long-term success: collaborative and meaningful engagement with all stakeholders. Early collaboration—whether with regulatory authorities, iwi (tangata whenua), or affected communities—is what can ensure management of challenges, risks, and expectations throughout the remediation project.
An example of this is a multi-year remediation project in New Zealand, which has shown the critical role of collaboration and engagement in delivering meaningful, sustainable outcomes, while navigating cultural, technical, and social complexity.
Project overview
This 16-hectare site, formerly an agricultural chemical production facility, operated for over 60 years and saw multiple changes in ownership, including a period under Regional Council management before returning to the client. Throughout its operational lifetime, contamination of land and groundwater occurred, leaving behind a complex legacy of environmental challenges.
In early 2023, the site was purchased by the client committed to undertaking a full detailed site investigation (DSI) and subsequent remediation as required. Building on the worksite’s complex history, regulatory requirements, and cultural significance, Tonkin + Taylor was engaged to prepare a sustainable remediation road map using a multi-phased approach. This project reflects not only technical ambition but also a commitment to genuine engagement with affected communities, iwi, regulatory authorities, and local stakeholders.
The road map to remediation: a multi-phased approach
The development of the Tonkin + Taylor remediation road map incorporated site-specific complexities and sought to address technical, social, cultural, and logistical challenges. The phased approach was designed to adapt over time as new information emerged and to accommodate external factors influencing the timeline.
Simplified phased approach:
1. Phase 1: review, update, and stabilize
With the site now non-operational, the first steps involved updating existing plans, including stormwater and groundwater management protocols, to manage environmental risks during the interim period.
2. Phase 2: site investigation planning (PSI)
Desk-based review and Preliminary Site Investigation (PSI) planning, including gathering historical data on site contamination. This phase incorporated opportunities for enhanced engagement, including interviews with former employees and the community to gain an understanding of the site’s legacy.
3. Phase 3: detailed investigation + risk assessment
Using the conceptual site model (CSM) from the PSI, Tonkin + Taylor developed a comprehensive Sampling and Analysis Plan (SAP) to characterize the nature and extent of contamination. Targeted investigations applied advanced methodologies to address the site’s challenging geology, hydrogeology, and contamination profile.
4. Phase 4: consenting and planning
Understanding the full extent of contamination will inform potential remedial options. Addressing and obtaining additional consents is critical as remediation progresses due to uncertain contamination levels and the absence of a pre-determined future site use.
5. Phase 5: active remediation
Where required, remediation activities (yet to be implemented) will address contamination hotspots while considering sustainable remediation practices.
This approach provided the flexibility to pivot as engagement and technical findings evolved—and was underpinned by a dual focus: parallel technical progress and continuous, meaningful engagement across all stakeholders.
Navigating complexity through engagement
While the technical challenges of the site were significant (including complex geology and hydrogeology, diverse contamination types, and multi-layered deliverables), non-technical complexities amplified the need for a thoughtful engagement strategy.
Client engagement for an international perspective
With the client not based in New Zealand nor initially familiar with the local environmental, cultural, and regulatory landscapes, Tonkin + Taylor took an active role in educating and supporting them. Key efforts included:
- Tailored project orientation: Educating the client about New Zealand’s cultural values, regulatory frameworks, and environmental expectations via briefing sessions.
- Public affairs support: Providing media training and updates about the political landscape to prepare the client for public and media attention.
- Iwi engagement framework: Facilitating monthly hui (meetings) between the client and tangata whenua to foster cultural understanding.
Community engagement
Given the site’s long history of agricultural chemical production, public scrutiny was inevitable. Recognizing this as an opportunity rather than a challenge, Tonkin + Taylor developed robust engagement tools to build transparency and trust, including:
- Community survey and interviews: A dedicated online survey hosted on the project website and enhanced with local media advertising. The team physically distributed 500 letters and employed a local resident to boost engagement. Results were backed up by in-person, phone, and email interviews with former employees and neighbouring residents.
- PSI community summary: Condensing a 137-page PSI report to an accessible 4-page summary posted on the project website for public viewing.
These efforts allowed for meaningful community input, improved understanding of legacy impacts, and ultimately reduced resistance by building transparency into every step of the project.
Cultural engagement: iwi collaboration
The site’s high cultural significance required a dedicated and respectful approach to tangata whenua engagement. Beyond traditional consultation, Tonkin + Taylor positioned iwi partnership as integral to every phase of the project. Key actions included:
- Appointing a Māori advisor to bridge the gap between the client and iwi.
- Facilitating site blessings and providing dedicated cultural monitors for upcoming investigations to ensure cultural values were upheld during physical works.
- Ensuring collaborative decision-making on remediation strategies, integrating mātauranga Māori (Māori knowledge) into the technical approach.
Managing external factors and complexity: from obstacles to opportunities
Delays resulting from external influences were inevitable across the project’s multi-year timeline. Instead of problems, these delays became opportunities for engagement, refinement, and alignment:
- Regulatory updates: Delays in management plan reviews allowed Tonkin + Taylor to liaise with new council representatives, improving alignment relationships.
- Independent review process: Engaging an independent peer reviewer for all deliverables ensured technical rigor while introducing a second perspective.
- Community tools: Community interest sparked the development of user-friendly tools for sharing project progress such as the dedicated project website.
A collaborative pathway to sustainable remediation
This multi-phase remediation project demonstrates that the success of complex contaminated land projects is not purely dependent on technical achievement. Rather, it is built on early, genuine, and sustained engagement with iwi, regulators, communities, and clients.
This article was submitted by our Corporate Partner.