Tasman region

The varied topography and patterns of precipitation in the Region combined with the complex geology creates unique patterns of water availability and demand. 70% of the Region is comprised of conservation land with annual precipitation levels up to 6000mm, while only 5% is flatter lowlands with precipitation totals down to 900mm.

The lowland areas in the eastern regions have the highest population and industrial concentrations as well as intensive horticulture areas such as pipfruit, market gardens, vineyards, berries and hops. Much of this water demand is met from the groundwater which is linked closely to surface water sources.

Thus high abstraction rates pose risks to maintaining instream river flows as well as positive aquifer pressure to limit salt water intrusion at the coast. Detailed water management plans for these areas are designed to ration water abstraction during periods of high demand and low availability so as to protect the river flows and aquifer integrity. The Waimea area has an over allocated water resource and hence water rationing is a routine practice during most summer months. The Waimea Community Dam is now in the commissioning phase and once operational hopefully beginning of 2024, will store water in the winter to be released in the summer to augment river flows and reduce the frequency of water rationing.

The regions to the northwest and south are generally wetter and are dominated by dairy farming. Traditionally irrigation in these areas has been limited, but in the last decade water demand has begun to grow.