Surplus water available from river
Waikato has a river of two halves when it comes to demand on the region’s water.
Surplus water has now become available for allocation at various points along the Waikato River, including the iconic Huka Falls, after work by the regional council and water take consent applicants.
But that good news is offset by warnings that urban and industrial developments in fast-growing north Waikato could be affected by pressure on water resources there.
The issue of allocation pressure on the region’s rivers is a key one for the regional council, which has to manage sometimes conflicting demands to protect the environment and to enable economic activity and housing growth.
In the past, there has been more water sought than is available for allocation from the Waikato and Waipā rivers. But a report to last Tuesday’s environmental performance committee noted that surplus water was now available at three key points along the Waikato River.
Resource use director Brent Sinclair said there had been a queue for water for a long time, with more sought than was available. Applications were dealt with on a first in, first served basis.
But proactive work by consents staff with applicants and ‘‘pencil sharpening’’ by those seeking water to reduce their requests ‘‘has meant we’re in a position where we have more water to allocate than we have water sought’’, he said.
At one point on the river, this equated to more than 100,000 cubic metres a day being free of allocation.
Sinclair told Stuff that the ‘‘pencil sharpening’’ reflected ‘‘public-spiritedness’’ on the part of applicants. But he also noted the council’s ability to hurry things along and withdraw allocation rights if water wasn’t being used.
Despite the good work, there were still hundreds of applicants in the queue, as they all needed to go through the consents process.
And, in a separate report on water quantity, staff noted an overall declining rainfall trend in the region since 1960, and an increase in potential evapotranspiration from the 1990s to 2020.
‘‘This drying has resulted in a reduction in mean river flows and allocable flow, particularly during summer.’’
The report noted that the Piako River (which drains to the Firth of Thames), the Whangamarino River in north Waikato, and the Pokaiwhenua Stream near Maungatautari were experiencing ‘‘heavy allocation pressure’’. The latter two flow into the Waikato River.
The report said the Piako and Lower Waikato River area (where the Whangamarino is sited) had experienced the greatest declines in annual low flow, rainfall and water availability.
‘‘Incidentally, the Lower Waikato area has the fastest population growth and potential increase in water demand in the region’’, the report said, a reference to urban and industrial developments.
‘‘There are some pinch points in the region,’’ Sinclair told Stuff. A regional plan review under way would tease out the detail of these potential problems and possible responses, he said.