Practitioners' Perspective on Protecting Freshwater Biota and Habitats at Flood-Relief Pumps in New Zealand

Abstract

Land drainage infrastructure, including flood-relief pumps, plays a critical role in protecting life and property, and for maintaining productive land. However, there is increasing recognition of the significant negative effects of flood-relief pumps on aquatic species and habitats. Cultural drivers and recent legislative changes in Aotearoa New Zealand are causing owners of land drainage assets (generally New Zealand's regional councils) to consider how they can mitigate their environmental impacts while continuing to maintain service levels. Resolving this challenge in New Zealand was the focus of a collaborative workshop held in February 2024. It brought together researchers, ecologists, asset managers, policy and planning specialists and engineers from regional and central government entities. Participants unanimously accepted that old ways of thinking have led to the environmental problems we face today. We need to rethink the reason the infrastructure exists, how it is operated, and how environmental considerations can be incorporated – to deliver financial, environmental, cultural and socio-economic benefits from flood-relief pumps and associated infrastructure. This was broadly captured under the concept of applying a hierarchical approach of ‘remove’ (the pumping station), ‘replace’ (harmful infrastructure with fish-friendly equivalents/alternatives), or ‘mitigate’ (the effects by modifying infrastructure and/or operation to improve two-way connectivity). All participants recognised a need to prioritise remediation efforts. Resourcing is scarce, and so there is a need to ensure that investments target interventions that achieve the best outcomes in the right places. This requires strategic spatial planning of management actions. Many barriers to uptake were identified throughout the day, including socio-political challenges, cost (upfront versus lifetime), current knowledge of existing staff and reliable evidence on effective solutions. A key takeaway message was the need for holistic, multidisciplinary, evidence-based approaches to finding solutions.