CANBERRA, Sept. 11 (Xinhua) -- Australia's intensifying La Nina cycles bring heavy rains that are increasingly causing ground movement, threatening the stability of homes and infrastructure, new research shows.
Prolonged La Nina rainfall is increasing shrink-swell in clay soils, destabilizing foundations, cracking pipelines, and damaging roads, according to a statement released Thursday by the University of South Australia (UniSA).
These soils repeatedly expand when wet and contract when dry, causing increasingly severe and widespread ground movement, it said.
Researchers analyzed over 100 years of rainfall and climate data, showing La Nina events fluctuated with frequent episodes in the late 20th century, a lull afterwards, and then a recent resurgence in the last 25 years.
Expansive clay soils swell and shrink with rainfall changes during both La Nina and El Nino cycles, according to the study, published in the Journal of Environmental Management.
The La Nina event that occurred at the break of Australia's Millennium Drought (1997-2009) caused soil expansion that damaged thousands of houses built during the drought.
"Even small shifts in climate cycles can lead to cracking, subsidence or costly repairs," said co-author, UniSA Professor Simon Beecham.
Beecham called for urgent inclusion of climate change in development strategies, warning it could seriously affect many Australian homes but has so far been overlooked. ■
