Untangling the Gordian knot: estuary survival under sea‐level rise and catchment pollution requires a new policy and governance approach

ABSTRACT Many estuaries are squeezed between sea‐level rise, coastal hardening and adverse cumulative effects from unsustainable catchment activities. In Aotearoa New Zealand, there is little planning to provide future accommodation space for estuaries. A complex knot of policies and plans, and accompanying poor implementation also affect ecological sustainability. We examine these issues for Brooklands Lagoon/Te Riu o Te Aika Kawa, a tidal lagoon northeast of Christchurch/Ōtautahi. It is within the takiwā of Ngāi Tahu iwi and Ngāi Tūāhuriri hapū, and the jurisdictions of Christchurch City Council and Environment Canterbury. The estuary is influenced by three rivers, and surrounding land use is managed under three different statutory resource management plans, along with several non‐regulatory strategies and organisational management plans. However, these plans are poorly integrated and estuarine ecological health is compromised. The incoming tide of resource management and local government reform will add complexity, but also an opportunity to accommodate and enhance the estuary as a blue carbon sink, and to restore cultural and ecological values. This requires specific recognition of estuaries in the proposed managed retreat and spatial planning laws, and within the replacement resource management statute. Legal recognition of Indigenous customary rights could also produce novel governance models to improve management.