DAM ENGINEERS this week played down fears expressed by climate experts that earthfill structures would be more likely to collapse in the face of increasingly heavy rainfall.
Authors of a new report, Assessment of potential effects and adaptations for climate change in Europe, said that earth slopes would be destabilised as a result of increased saturation caused by heavier, more prolonged rainfall.
The report, launched last week, said the water content of earthfill structures is set to rise significantly over the next few decades. Ground water levels will also rise, affecting foundations.
But engineers disputed the claim. Binnie Black & Veatch technical director Andrew Rowland said there was a theoretical danger that higher water pore pressure on the down stream slope of embankment dams would result in structural failure.
But he said that modern dams were designed with a far larger surface water drainage capacity than required and would be able to cope with foreseeable increases in rainfall and extreme events.
All old dams have been inspected to ensure they measure up to current performance standards, he added.
Increased water pore pressure is likely to result in localised soil slump on downstream slopes, requiring increased maintenance, said Brown & Root chief dam engineer John Gosden.
If unchecked, soil slump could, over a long period, lead to more serious damage.
The report, published by the Jackson Environment Institute for the European Commission, predicts rainfall will increase by up to 4% per decade.
It says that by 2050 changing weather patterns will result in far wetter winters and drier summers. Rainfall will be concentrated in prolonged, heavy downpours rather than evenly spread through the winter months.