Water allocation modelling as a tool for freshwater quantity accounting

Water allocation modelling is relatively new to the scene in New Zealand but it’s rapidly becoming a hot topic. Increasing pressures on our freshwater systems from population and industry, and a changing climate, have motivated recent mandates on freshwater quantity accounting. Through the National Policy Statement for Freshwater Management, regional councils are being required to adopt policies and tools to “sustainably manage the taking, using, damming, or diverting of fresh water” and to improve their information on freshwater takes by developing “freshwater quantity accounting systems”, which presumably means databases, spreadsheet calculations and more sophisticated computational tools – like water allocation models. In this paper, Dr Tim Cox discusses the challenges for regional councils in decision making around water allocation and the role that water allocation models can take in that process, illustrated through case studies.