Rainfall provides temporary relief to dry conditions

While this week’s rain is a welcome reprieve for gardens, pastures and water tanks, it is likely to provide only one-week’s relief to the low river and groundwater levels, particularly in the Mataura and Ōreti catchments.

Environment Southland chief scientist Karen Wilson said this week we have received between 20 and 35mm of rain across Southland, and Metservice predicts a little more in the next 24 hours.

“This will likely see rivers rise slightly for a short period and provide some temporary relief for freshwater ecosystems, however, further sustained rainfall is required to bring water levels back up to within a normal range.”

The MetService long-range forecast is predicting near normal monthly rainfall totals for Southland in March, with drier than normal rainfall over the April and May period.

“This could mean a period of up and down river levels, which would impact consent holders in particular as river and groundwater levels go above and below their consented restrictions.”

In January, Southland received about 40% of its normal average rainfall. North-western and coastal Southland were particularly dry experiencing 19% and 37% of normal rainfall respectively.

Many aquifers are within the normal range for this time of year, however the Whitestone, Waipounamu, Wendon and Edendale aquifers were all below normal (within the lowest 10% of record observed at this time of year).

The January days were also hot, with all monitoring sites recording temperatures above average. Invercargill was 2.2°C above average and had 13 hot days (where the temperature gets above 25°C), which is well above the average number of four.

Across Southland, about 70 consent holders have already had to cease abstraction or have some level of restriction with their water take. Southland and Gore District, and Invercargill City Councils all have some level of water restriction and are encouraging their residents to conserve water.

“Those in towns should check their local council website for information on water restrictions and advice on actions you can take to conserve water,” Karen Wilson said.

In addition, farmers are encouraged to check their consent conditions, check and maintain their bores, and visit the Beef and Lamb or DairyNZ websites for tips on further actions that can be taken on-farm to conserve water.

On Thursday 23 February, a stakeholder group is meeting, convened by Environment Southland and the Rural Support Trust.

Environment Southland general manager integrated catchment management Paul Hulse said the group includes councils, rural agencies and Ministry for Primary Industry representatives.

“The group is coming together to share science, particularly around forecasts and hydrology, and gather information to support councils and agencies in planning for their communities’ needs if the situation worsens.”

More information about the current low water levels is available on Environment Southland’s website at www.es.govt.nz/low-water-levels.