News release
5 May 2008

Wet weather breaks drought for most

Above average rainfall this April has boosted river flows, aquifers and soil moisture levels, effectively breaking summer’s drought in most parts of the region.

Greater Wellington's monthly hydrological summary for April shows that overall rainfall totals for the month in the west of the region were 150% to double the long-term averages.

But the eastern Wairarapa hill country has remained drier than usual with our monitoring site ‘Tanawa Hut’ receiving only half of its long term rainfall average for the year to date.

The main feature of the month was a northerly downpour early on the 30th that triggered flood warning alert systems in the Hutt and Waikanae rivers.

The downpour boosted April rainfall totals to 143mm for Greater Wellington’s Karori monitoring site and 138.5mm for Waikanae, both well above average for the month.

The Wairarapa plains also enjoyed significant rains during April and rainfall totals for the year to date are now 80% of average, up from about 60% at the end of March.

Although the rains boosted river flows significantly, most rivers still had below-average flows for April due to the long-lasting effects of the extended dry spell.

However, aquifers recovered significantly due to more rainfall, lower evaporation and less irrigation.

Soil moisture levels also recovered significantly increasing almost to the pre-summer levels at Greater Wellington monitoring sites on the Wairarapa plains. But the drier eastern hills need more rain to eliminate the moisture shortfall from the dry summer.

This summary is based on data from selected monitoring locations in the Wellington region. Greater Wellington monitors rainfall, river flows, groundwater levels and soil moisture at many locations that may not be mentioned in this summary report. Maps of site locations and up-to-date data can be found at www.gw.govt.nz/monitoring

ENDS

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