Rain provides some relief for parched Lake Opuha
Last week’s rainfall made a minimal impact on the parched Lake Opuha, but overall provided some relief Opuha Water Limited said.
As of Monday morning, Lake Opuha was sitting at 372.8 metres, which equates to 4.4% of its capacity, up from 371.4m (2%) before last week’s rainfall.
On March 21, Agriculture Minister Todd McClay, declared a medium-scale adverse event for the Canterbury and Otago regions because of the drought conditions.
Opuha Water Limited was forced to end irrigation on its scheme on March 23 with just 3 metres of water remaining in the lake.
The weather system, which brought varying amounts of rainfall to locations across South Canterbury last week, was the first significant rainfall in several months for the drought stricken region.
Lake Opuha received approximately 45 millimetres of rain in upper catchment, and around 20-30mm closer to the coast, Opuha Water Limited environmental manager, Julia Crossman, said.
Crossman said while the increase in the lake’s level had not been significant, the rain had helped in other ways.
“It has certainly been well received by shareholders scheme-wide, raising soil moistures,” Crossman said. “It has also provided additional lake storage that can be utilised to maintain river flows downstream if the autumn and winter are dry.”
Crossman said more frequent and consistent rainfalls were required over the remainder of autumn and winter to bring the lake levels to the normal range.
“There is currently no more rain in the forecast [for this week].”
In it’s April to June climate outlook, the National Institute of Water and Atmospheric Research had predicted temperatures were likely to be near average, or above average, for the east coast of the South Island. Rainfall was expected to be near normal or below normal for that period, and soil moisture levels and river flows would also be below normal.
Last week, an Environment Canterbury spokesperson said 2024 had seen some of the lowest river flows on record for some sites across Mid and South Canterbury.
“Lake Opuha is currently at its lowest level since the 2014-15 summer, which has led to very low flows in the Ōpihi River,” the spokesperson said.
Last week it was announced the Opuha Environmental Flow Release Advisory Group had requested an extension to the water shortage direction.
A notification, issued by ECan on April 9, said the direction restricting water takes would continue for 14 days from April 8. The notification was for the Ōpihi River and its tributaries and it does not include the Temuka River and its tributaries.