Working with nature to solve the flooding problem
- Created on Saturday, 23 January 2016 16:54
- Written by Guest Writer
Janice Fuller, Consultant ecologist
As soon as the country was hit with the latest flooding crisis, the blame game started. The usual suspects were cited: ‘the government’ for lack of action since the last major floods and ‘the planners’ for poor planning decisions (i.e. the councillors in many cases). Lip service is also given to climate change as the reason for the unprecedented weather events.
Increasingly, there is a perception that wildlife is prioritised over people in the management of flooding and that nature conservation legislation is partly to blame for the lack of action regarding flood control.
According to John Comer, President of the Irish Creamery and Milk Suppliers Association (ICMSA), “Farmers believe that birds, frogs and fish are getting priority over humans and human suffering.”
The Office of Public Works (OPW) is the lead agency for flood risk management in Ireland; however there is a plethora of other organisations with some responsibility for water and watery issues (National Parks and Wildlife Service, Environmental Protection Agency, Waterways Ireland, Inland Fisheries Ireland, Local Authorities, Electricity Supply Board). The lack of a single authority to deal with water is also blamed for the abundance of red tape and confusion underpinning a lack of co-ordinated action.
Flooding is a part of nature and is a natural phenomenon. Draining wetlands; building in flood plains; deforestation; agricultural intensification; interfering with the natural course of rivers and streams, and climate change, have intensified the impact of flooding with devastating effects for the communities.
Flood plains are flat plains along the course of rivers or streams that are naturally subject to flooding and therefore extensive building in these locations - as is the case in many parts of Ireland - is bound to lead to problems.
Vegetation, especially woodland, intercepts rainfall, and the loss of woodland, hedgerows and in particular wetlands on the landscape, as well as poor management of riparian vegetation, has led to greater run-off of water into streams and rivers.
We lost most of our native woodland resource long ago but continue to drain, infill and build on wetlands with little regard for their function on the landscape as natural sponges. Planting of native woodland is on the increase but much more is needed.
Global climate change is undoubtedly having an impact on Ireland’s weather patterns. The current flooding crisis came at the end of the warmest year globally on record. A very strong El Niño on top of ongoing climate change hit Ireland with six storms resulting in an entire winter's worth of rainfall falling during December alone.
Past approaches to flood management have been piecemeal and reactive. The focus to date has been on land drainage schemes (mainly for agricultural improvement) and ‘hard engineering’ solutions, such as flood walls, embankments, channels, drains etc.
Many local politicians, farm organisations and flood-affected businesses and communities are calling for further land drainage and flood control measures with the apparent aim of finding the fastest method of getting water through the country’s rivers and out to sea.
In many cases however, slowing the water down ― especially in the upper catchment ― would do more to mitigate the impacts of flooding as high rainfall events would be less likely to overwhelm natural or man-made defences. There will always be a need for the traditional flood control measures but a more sustainable and cost-effective approach is long overdue in Ireland and urgently required.
Sustainable flood management is achieved by a catchment-based approach that aims to protect existing natural defences such as wetlands and woodlands (that hold water and release it slowly), and promotes ‘soft engineering’ solutions (e.g. restoring and creating wetlands, planting trees, reconnecting rivers with their floodplains, restricting development in flood plains).
The aim is to restore a river’s natural capacity to cope with floods via its wetlands, floodplain and riparian woodland. Traditional flood control measures will still be required where they are the only option, as in many urban centres. In addition, innovative techniques can be utilised to hold water upstream and release it slowly, by creating water storage areas and using porous dams to release water slowly, for example.
Hard engineering solutions focus solely on the symptoms of flooding and not on the cause. The symptoms are felt downstream in towns and villages, but the actual causes usually begin upstream.
The current Irish National Flood Policy strongly emphasises catchment-wide flood risk assessment and management (CFRAM); however development of CFRAM plans still appear to be at an early stage. Soft engineering solutions are mentioned as an option in the Policy but there is little evidence that this approach has been adopted to date.
The policy states: ‘The contribution of wetland eco-systems to flood attenuation needs to be formally recognised' but there has been no action to capitalise on this natural resource. The OPW has produced flood maps as part of the Policy but there doesn’t appear to be any assessment of natural flood defences.
A national survey of wetlands should be conducted to assess the extent and condition of this resource and to determine the potential for restoration and enhanced flood mitigation. It is impossible to completely control flooding but it is possible to mitigate the impacts if we adopt a sustainable approach to flood management based on the whole river catchment, and employ flood control and mitigation measures including soft engineering techniques as well as the traditional solutions.
This approach is likely to be more cost effective with additional benefits for biodiversity and the environment. If we accept that soft engineering solutions, which recognise the value of wetlands and riparian woodlands, are part of the way forward in flood management, a multidisciplinary approach is essential i.e. engineers, hydrogeologists, hydrologists, ecologists and planners working together.
In addition, a mechanism that allows all the relevant state agencies and organisations to work together and develop a common policy framework in relation to flood risk management and the protection of water quality, biodiversity and the environment is urgently required to avoid contradictory policies, confusion and delays. Finally, we have to accept that there are unlikely to be any solutions that will completely cope with extreme weather events and there will always be flooding to some extent. In the current era of climate change we need more than ever to work with nature rather than against it.
Slowing the flow - examples from the UK