Climate impacts on the national water cycle

Rakaia river and surrounding mountains Photo by David Allen

National hydrological and water resource impacts of climate change

This century, climate change will alter New Zealand’s natural water cycle significantly. It will change how much rain and snow we receive, and at what time of year. It will change how much water is stored in the soil, snow, glaciers and aquifers. It will change how much water evaporates back to the atmosphere and how much flows through streams and rivers to the coast. And it will change the severity of droughts, floods and power shortages.

In New Zealand, fresh water is central to our natural environment, economy and way of life. It has shaped our landscapes and wildlife, supports farming, tourism and other industries, supplies over 50 percent of our electricity through hydropower, and is integral to our heritage and sense of place.

This research project will conduct a comprehensive national assessment of the impact of climate change on New Zealand’s hydrological cycle this century. Using NIWA’s hydrological modelling tool, TopNet, we’ll examine the potential effects of climate change on the movement of our freshwater, from the mountains to the coast, with a focus on agriculture, hydropower and flood hazards.

As part of this project we’ll identify where New Zealand’s water cycle is most vulnerable to change and develop a new approach to calculating the likelihood and severity of future floods. The data and results we generate will also help other research projects study the implications for flood management and irrigation supply.

Project contact: Christian Zammit, NIWA
Project budget: $400,000
Project duration: July 2017 – June 2019

Research and findings:
National hydrological and water resource impacts of climate change Daniel Collins & Christian Zammit, Deep South Symposium


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