ECan warns of dry summer

The region is in for a long, dry summer according to Environment Canterbury's latest water resource report.

ECan is predicting declines in groundwater during the anticipated El Nino summer as high levels of irrigation and low river flows look set to affect shallow aquifers.

Heavy rain in May gave the region's groundwater a boost, but a lack of significant recharge since has meant that many wells, while currently at average or average to low levels, are declining.

Climate predictions show the El Nino summer will bring dry conditions.

Temperatures are predicted to remain normal between now and December while rainfall isn't expected to fall below average until early next year.

It wasn't all bad news though, as the report noted a nine-year declining groundwater trend was broken as deep inland aquifers were recharged during heavy rainfall in May.

The recharge appeared to have been significant enough to lift aquifer levels three to five metres higher than in 2008 and break the declining trend.

Ecan's 70-page booklet outlined surface water resources including rainfall trends, snowfall, riverflow and water balance while looking at groundwater resources and climate outlook in the region.

South Canterbury received above average amounts of rain through winter to the start of spring, while rainfall levels across the region since then were predominantly below average.

Soil moisture levels over most of the region were above average for the early part of the winter, but had declined to below average levels by the end of September.

Data showed South Canterbury received average rainfall between May and September.

The Opihi, Pareora, Waihao and Rangitata rivers were flowing at an an average 130 per cent of the long term median between May and September.

Rangitata's rainy start to winter resulted in a good aquifer recharge with groundwater levels dropping at higher than usual rates around August.

Most groundwater levels were around average but trended down due to early irrigation start-up.

Groundwater levels in Pareora were very low in January but also got a recharge in May and have fallen to below average levels since.

- © Fairfax NZ News