A survey of nitrate contamination of New Zealand aquifers was carried out in mid 1998. This involved reviewing existing data to determine the extent and magnitude of nitrate contamination of New Zealand's groundwater systems. Many of New Zealand's trading partners have implemented policies designed to reduce nitrate concentrations in aquifers by controlling land use activities, and it is important that New Zealand quantifies its position and response. These areas, as expected, are associated with intensive farming. Several other areas are below the MAV but require monitoring.
Irrigated agriculture is by far the largest consumptive user of water in New Zealand.
Over 400,000 hectares of land are irrigated throughout the country, consuming five times more water than the total domestic requirement for the whole of New Zealand. Peak demands in irrigation consume up to 15 times the domestic demand and usage is increasing rapidly. The ultimate extension of MAF operational research and BMP-funded irrigation initiatives is the development, and implementation, of irrigation BMP guidelines. The guidelines will provide land managers with practical information to help them reduce the environmental impact of irrigated agriculture and increase their profitability. The guidelines are intended to complement a set of practical indicators of sustainable irrigated agriculture.