The Realities of Adaptive Flood Risk Management
Stormwater Conference
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In recent decades, the Ōpāwaho/Heathcote River catchment in Christchurch has experienced a series of floods which have severely affected people, buildings and the environment. The risk of flooding has been substantially exacerbated following the Canterbury Earthquake Sequence, and now the catchment faces increasing risk with climate change, in particular, rising sea levels. As part of ongoing wider work to build resilience and plan for a range of natural hazards, Christchurch City Council is developing a catchment-wide flood management plan for the Ōpāwaho/Heathcote. The planning is embedding recognised climate adaptation principles to prepare for a 100 years’ time horizon.
This paper presents a range of observations made through the planning process in this complex catchment. Whilst no decision has been made within the project timeframe to implement any of the potential long-term adaptive option pathways developed, two important outcomes have resulted at this stage. Firstly, the specific information developed for this key catchment in the city is informing the engagement and ongoing drive for resilience to all hazards, and particularly how such dynamic catchments can adapt to the impacts of climate change. Secondly, having already worked towards an in depth understanding of the catchment and the range of possible options when flooding occurred in July 2017, the Council was able to rapidly consult and approve significant works which are underway.
These works, understood in the context of longer-term adaptation, will substantially reduce flooding in the current climate and some way into the future. This paper outlines some challenges and solutions encountered in the ongoing planning process which have relevance to the wider management of flooding both inland and near the coast. Climate change may be viewed as a ‘creeping’ hazard at the present time, but influential events can occur suddenly, and having a level of planning in place facilitates timely, sustainable and adaptive responses.