Impacts and implications of climate change on wastewater systems: A New Zealand perspective

Wastewater systems provide a critical service to society, and their vulnerability to the impacts of climate change. places the health and sanitation of many communities at risk. The impacts of climate change on wastewater systems are numerous and can lead to wide ranging implications over changing timescales. This paper considers the significance of the impacts and implications, how they will be distributed across different groups, how they will manifest in different contexts and locations, and conclude by proposing a range of guiding principles for local government decision makers. The research firstly considered direct climate-related impacts on a range of wastewater system elements (including reticulated wastewater systems, on-site wastewater systems and treatment plants), in both urban and peri-urban settings in New Zealand. The impacts identified for each aspect of the wastewater network were found to fit within three broad impact themes; nuisance flooding spills and odour, water quality deterioration due to increased uncontrolled discharges and damage to infrastructure. The research shows that the immediate and long-term implications resulting from these impacts are likely to be experienced widely across the social, cultural, environmental and economic domains. Examples include loss and damage to assets - leading to disruption to communities, water quality deterioration with consequential social, environmental, economic and cultural effects, public health risks, and economic costs related to damages, foregone production and insurance. Cultural implications are of particular importance in a New Zealand context, given the strong connection of Maori to the environment and water.