Safety of peat dikes during a drought raises concerns

THE HAGUE - The question of living safely behind Dutch dikes became more problematic when during the night of August, 25, 2003 a local Wilnis area dike was dislodged by some seven metres along a stretch of 60 metres. The calamity resulted in about 230,000 m3 of water flooding a residential area and causing material damage worth about 10 million euros. The occasion involved no storm, no tropical downpours or high water levels but, as strange as it may sound, a lengthy drought. The 2003 breach caused consternation among dike district officials everywhere who have since been monitoring dikes with a similar structure as that of the Wilnis dike: peat soil used, perhaps centuries ago, on top of a different soil structure. With peat material shriveling during times of drought, water pressure can push the dike off its footing, the Dutch learnt the hard way. The Lowlands are going through another drought currently, leading to questions from Wilders’ PVV party regarding the safety of peat dikes. The junior minister responsible for this portfolio, Joop Atsma, was ready with an answer. The country has about 1,000 kilometres of ‘peat’ dikes (veendijken) of which about 300 kilometres has been upgraded since 2003, and another 300 kilometres merits a higher level of monitoring. Meanwhile, the Wilnis breach exposed another problem to claimants for compensation of the damage. Government agencies may not be as fully responsible to pay claims as previously assumed. Officials stated that they had taken sufficient measures against excessive rainwater and melt water but that there had never been a failure due to a prolonged drought. Without sufficient instructions no one was blamed: therefore, the authorities could not be held responsible either.