A new monitoring station near Gore could shed light on how significantly melting snow impacts Southland floodwaters.

Environment Southland revealed in a report this week it had set up a monitoring station at Hyde Rock, north of Gore, which would provide live information on “snow conditions and weather variables relevant to snowmelt”.

Melting snow was a large contributor to Southland flood flows, but the council’s models did not specifically account for it prior to the project, the council report said.

“The benefits of this work extend beyond flood forecasting.

“Seasonal snow storage and snowmelt make important contributions to Southland’s river flows, lake levels and groundwater recharge, meaning changes in snowpack conditions have implications for future water availability.”

The arrival of snowpack monitoring and snowmelt forecasting meant the council had improved its flood forecasting capability, the report showed.

And the equipment appeared to have arrived at an opportune time, given the report also noted snow volume was expected to reduce 40%-50% under some climate scenarios.

By 2050, Southland’s snowline was projected to rise by as much as 300m, the report said.

“These changes have potential implications for water users, ecosystem health and long-term water resource management.”

The report explained melting snow could contribute significantly to flood waters in the Aparima, Oreti and Waikaia catchments, with melt already accounting for about 17% of flow during Waikaia’s September 2023 flooding.

The Hyde Rock snowpack monitoring station was located in Waikaia, and the snow melt forecasting model was for that catchment.

Hyde Rock was selected because it had good accessibility and had been used for measuring rain water and air temperatures over the past 20 years.

Upgrades to the station were finished in April, and the forecasting model was completed in June.

LDR is local body journalism co-funded by RNZ and NZ On Air.