Information on water allocation in New Zealand

Abstract

Water allocation is identified as a high priority in the Ministry for the Environment’s Draft National Agenda for Sustainable Water Management. The purpose of this project was to develop an information base concerning the status of water allocation in each region, and the systems that are being used to allocate water. The information base will contribute essential information to ongoing work in water allocation. There are two parts to the report. First, a quantitative analysis based on consent database information to assess where water is allocated from and the uses it is allocated to. Secondly, an overview of current water allocation practice within New Zealand based on interviews with regional council staff and review of documents including draft, proposed or operative regional water plans. The quantitative analysis has shown that: • 70.5% of all water allocated in New Zealand is allocated from surface water, 29.5% is allocated from groundwater. • 77% of water allocated is for irrigation, 16% is for community, municipal and domestic uses, and 7% is for industrial takes. • 58% of water allocated in New Zealand is allocated from the Canterbury region. The North Island accounts for 17% of water allocated. • 19% of the current weekly allocation has been allocated since 1990. The majority of water in New Zealand was therefore initially allocated under legislation predating the RMA. • There is approximately 500,000 hectares of irrigated land in New Zealand, 350,000 hectares of which is in Canterbury. • 41% of the irrigated land area is irrigated from groundwater. • The area of irrigated land is increasing at around 55% each decade. • The “at farm gate” value of irrigation water is estimated to be around $800 million. The figures above are all based on weekly allocations and will typically relate to the maximum volumes required during a dry summer week. Water taken for hydro-electricity generation or any other non-consumptive use has been excluded from the analysis. The figures are for allocated volumes rather than use. Because irrigation is the dominant use of water, actual use is greatest in dry summers. When measurements of actual water use have been compared to allocated amounts on a weekly basis, the total take from a water resource is seldom more than 40% of the allocated volume. Annual use varies between 20% and 65% of the allocated volume depending on climatic conditions. The second part of the report summarises the management of water quantity and water allocation by region. Issues addressed are, setting minimum river flows or groundwater levels, determining limits to the total amount of water that can be allocated from a resource, dealing with over-allocated resources, managing abstractions during water-short periods, promoting efficient use, consent administration, and enforcement/compliance issues. The approach chosen by each council depends on a wide variety of factors including: the dynamics of a water resource and the ecosystem it supports, the associated values, the history of water allocation, the level of information available, and the political environment. While it is not appropriate, given differences in these factors, to identify a “right” way to allocate water, the report describes a range of issues, obstacles and research needs for the implementation of successful water allocation systems.