Parts of the Waikato’s groundwater resources are under stress from overuse, this week’s Environment Waikato Environment Committee meeting heard.
Groundwater (water stored in underground aquifers) makes up about 90 percent of the Region’s freshwater supplies. Most areas of groundwater are under low or medium stress, with less than 30 percent of the available groundwater allocated for use.
However 13 aquifers have been identified as under high stress, with more than 30 percent of water allocated, hydrologist Dr Edmund Brown said.
Groundwater is used extensively for agriculture, water supply and industry and about 400 new wells are drilled each year. With the increasing demand for groundwater it was important to identify areas in the Region where there was high use to prevent adverse environmental and economic effects.
“The amount of water in our aquifers will sustain our needs as long as we use the water efficiently. Recent years have seen large increases in the amount of surface and groundwater used in our Region.”
When too much water was taken, groundwater levels declined, not enough was available for everyone to use, less water flowed into streams, land could subside and in coastal areas salt water could contaminate the groundwater.
Larger water takes were increasing steadily, especially during the dairy boom, and substantial increases were occurring from irrigation and intensified land use.
The next step was to do more detailed investigations in areas of high use to assess the environmental effects of increased groundwater use on spring flows, stream flow and salt water intrusion. This would also provide better estimates of available groundwater.
Further studies would be done in Pukekohe, Cooks Beach and Reporoa.
This would help the Council’s Water Allocation Project review its policies to ensure there was a fair and efficient allocation of available water in the Region, he said.
Cr Steve Osborne said groundwater availability and quality was important for the continuing viability of the farming community.
“We have to be careful to use water efficiently so that there is enough for rural, industrial and urban uses.”