Pat O’Brien, environmental scientist
The recent apocalyptic flooding episodes that inundated large parts of the country during December 2015 and early 2016 were for those affected, a case of déjà vu – mindful of the 2009 floods.
Granted, we are all aware that flooding is a natural process that can happen at any time in many different locations. Flooding from the sea and from rivers is probably best known; however, prolonged, intense and localised rainfall causes sewer and drain flooding; overland flow and groundwater flooding with significant impacts on human activities such as housing, transport, public service infrastructure, commercial, industrial and agricultural enterprises.
The health, social, economic and environmental impacts can be significant and cause wide community impact, evinced from the recent scenarios – notably in the Shannon catchment, which by comparison with the rest of the country, had terrible consequences in terms of loss of property and personal deprivation.
Few lessons learnt
Have any lessons been learned, let alone implemented, from the deluge of 2009 when we were assured by the then Minister of State with responsibility for the OPW, that flood mitigation measures would be implemented against future events?
Some were, but not enough. Granted, many CFRAM (Catchment Flood Risk Assessment Management) plans were drawn up, but very few were implemented in flood-prone areas.
For decades, the main problem regarding flood control in river basins has been interference with natural hydraulic patterns such drainage of wetlands, most notably within the Shannon Catchment, which has five wetlands of international importance.
Development can also exacerbate potential flood zones by accelerating and increasing surface water run-off, altering watercourses and removing floodplain storage.
Wetlands, or the lack thereof, were a significant factor in the severe flooding in the Upper Mississippi and Missouri River Basins in the summer of 1993.
Damage associated with the flooding was undoubtedly worse than would have been if flood-plain wetlands had still been in place. Human modification of the original wetlands destroyed their ability to modify flooding. Flood control, however, is only one of the values that wetlands have for society.
In order to protect wetlands, the public must first recognise their value. People need to understand what is lost when a wetland is changed into an agricultural field, a car park, or a housing development. Understanding the functions of wetlands will make it easier to evaluate wetlands when other uses are considered.
In the case of the Shannon catchment, decades of successive Irish governments have shown a lack of concern for the negative impact of large-scale drainage schemes. But of course, such schemes were aided and abetted by Brussels and Dublin by way of subsidies, resulting in large-scale farming development on reclaimed wetlands exacerbating the risk of flooding.
As a consequence of the 2009 floods, the situation regarding wetland development changed; however farmers then reacted angrily to proposed new environmental regulations that required planning permission to reclaim swampy scrubland or wetlands.
At the time, the European Court of Justice ruled that Ireland’s Environmental Impact Assessment (EIA) screening for certain agricultural development was in breach of EU directives. The regulations also allowed the removal of field boundaries, semi-natural areas and drainage and irrigation projects.
The president of the Irish Cattle and Sheep Farmers Association at the time described the new regulations as “an outrageous assault on property rights and the concept of freedom to farm”. That statement must now ring hollow in the ears of many farmers in the Shannon catchment who find themselves totally waterlogged as a result of their interference with wetlands.
The Dutch, despite most of their country being below sea level ― and unlike Ireland where the vast majority of the country is above sea level ― are well capable of managing flood episodes. They have undertaken ‘de-poldering’ – lowering or removing the dikes in some areas of farmland and designating the land as a flood zone.
In other areas, retreat is being managed by protecting farm houses and acknowledging that the farm land itself will flood. This is being done by demolishing existing farm houses, constructing giant man-made mounds (~20 acres each) and rebuilding farm houses on top of them (hopefully) higher than the flood waters would reach (~7-8m high).
One example is the Overdiepse Polder where sixteen farms have been designated as flood zones to protect the 140,000 residents of Den Bosch.
Adaptable and open-minded
The most important advice we can take from the Dutch experience of flood risk management is the need to be adaptable, open-minded to changing historic land-use patterns and be prepared to take radical solutions.
There is no point applying mitigation measures in one riverine locality to the detriment of another. What is needed is an integrated approach comprising a fit-for-purpose programme of mitigation measures.
Ireland has transposed into law the EU Water Famework Directive 2006 and the EU Directive on the Assessment and Management of Flood Risks 2007, but is falling far short of implementing the key requirements of those directives that relate to flood management in river basins.
It is little comfort to people affected by flooding to have ministers assuring them that everything will be done to prevent such future catastrophic floods. And happen they will as we are now in a cycle of much more frequent extreme weather events.
There are simple, basic practices to be followed to mitigate flooding in river basin catchments, such as non-interference with wetlands and non-felling of trees on high ground to promote sheep farming.
As pointed out by Dr Tom McDermott from the School of Economics and the Environmental Research Institute at University College Cork: “We appear as a society to be overly-exposed to flood risk. There are various reasons why developers and house builders do not take full account of flood risk when deciding where to build.”
As a small island nation replete with a network of lotic and lentic systems (lakes and rivers) this stands to reason.
Despite the severe flooding, there are still Irish local authorities and developers who are either wilfully or blissfully ignorant about allowing developments on flood plains. This will continue unless existing flood plain regulations are enforced and complied with.
The message: interfere with natural flood plains – by way of drainage, tree and hedge clearing, or building ― and you will suffer the consequences.