Region not at threat of drought
Wednesday, 11 February 2015 10:00 a.m.
Recent rain following a dry January means the Bay of Plenty is not currently at risk of drought.
February has so far seen 15-70mm of rainfall across the Bay of Plenty Regional Council’s monitoring network. Although this rain has been patchy, it has provided temporary relief across the region. At a few sites, including Kokomoka in the upper Rangitāiki catchment and Te Teko in the lower Rangitāiki catchment, this rainfall is already more than the total during January.
January was characterised by air pressures that resulted in an abnormal north-easterly airflow and a predominance of highs over the country. This resulted in an abundance of dry, warm and sunny weather for most of the country during January, which was reflected in the month’s below-normal rainfalls. January saw an average of 40 percent of normal for the BOPRC rain gauge network, with some sites as low as 14 percent of normal.
The lack of rain has resulted in soil moisture levels being below normal for the time of year in parts of the Bay of Plenty, with traditional dry areas such as Galatea, Rerewhakaaitu and Reporoa being very dry. Resulting stream flows are dropping, but reference flow monitoring sites indicate most rivers are still above or just approaching normal annual summer low flows.
The one notable exception is the Tarawera River, which is just below its average annual low flow.
“Rivers are at what we would call a mean annual flood,” says data services manager Glenn Ellery.
The council’s rain gauge figures show the Bay of Plenty had a wetter December than usual. The Whakatāne gauge at Kopeopeo recorded 161mm – 174 percent of normal – for December, and the gauges at Te Teko and Opotiki wharf had 141.5mm and 190mm – 143 and 183 percent of normal respectively.
“We were lucky to have rain in October and December last year, as this would have helped recharge the groundwater stores that act as the primary contributors to base flows during dry periods,” Glenn says.
“This in turn helped us prevent some of the extremes present in other parts of the country.
The Rural Support Trust, which has a principal role in monitoring adverse impacts on farmers and recommending drought declarations to the Hon Nathan Guy, Minister for Primary Industries, continues to monitor the situation.
For more information visit http://monitoring.boprc.govt.nz/RainfallMap/.