Freshwater monthly snapshot
Following a wet start to summer, rainfall across most of the region was average, or below average in some areas. River flows were close to average, with some early January sporadic rainfall in north Canterbury causing good flows in coastal streams.
Surface take restrictions for irrigation
The number of sites on restriction for the 2018 irrigation season to date have been steadily increasing since the start of 2019. The sites currently on restriction include smaller spring fed streams, and most of the lower reliability bands on the foothill and alpine rivers. Some of the higher reliability bands are on partial restrictions now also.
The bottom plot shows the history of the full 2017/2018 year for comparison.
Irrigation restrictions through October to the end of January 2019
Irrigation restrictions for 2017/18 season
Groundwater levels and forecast
Groundwater levels across the region were getting a bit low after a relatively dry winter, but they have responded to the rain of the past couple of months. They are currently at average levels for the time of year. The graph below shows the cycle since 2010 in an indicator well west of Christchurch.
Groundwater depth below surface in a West Melton monitoring well
Selwyn River/Waikirikiri flows
The good news for the Selwyn River / Waikirikiri, particularly the lower part below Chamberlains Ford, is that groundwater levels are still above average and there are still sustaining reasonably flows for Coes Ford, although several hot weeks have shown the flows to be declining slowly since early January.
The Selwyn River / Waikirikiri was high in late November (38-40 cumecs), following high rainfall, but flow has now ceased to flow under SH1. It is likely that the drying across the plains will continue for the remainder of the summer while the lower parts of the river will continue to flow.