Flood risk

The flooding at Blaendolau on Saturday 9 June 2012.

The flooding at Blaendolau on Saturday 9 June 2012.

22 October 2012

A report by researchers at Aberystwyth University into the causes and consequences of the June 2012 flood in Aberystwyth and surrounding villages concludes that events of this magnitude are characteristic of rivers that flow from the Cambrian Mountains in west Wales and should be expected again in the future.

Professor Mark Macklin, Dr Paul Brewer, Dr Simon Foulds, Rachel Betson and Dr Sara Rassner, from the University’s Institute of Geography and Earth Sciences, explain that extreme floods are likely to be repeated in the future and may even become more frequent in a warming climate.

However, the report also notes that although June rainfall totals in the Cambrian Mountains were high, they were not extreme and did not approach any UK records.

The amount of rain that fell appears to have been similar to the last serious floods in the Aberystwyth area in August 1973 and December 1964. Other serious flooding incidents that have occurred in the area include June 1935, June 1919 and October 1896.

The authors argue that compared to the earlier floods of 1964 and 1973, the 2012 flood was exacerbated by floodplain development.

Professor Macklin explains, “Since 1906, there has been a dramatic increase in building on the Rheidol floodplain. Most of the floodplain development has occurred in the last 30-40 years with the construction of Glanyrafon Industrial Estate, Parc-y-llyn Retail Park and, more recently, local council and government office buildings.

“Of particular concern is the development of camping and caravanning areas on floodplains which places a great deal of residents at a high exposure to flood risk. Although there were no fatalities, several car parks were flooded and this type of land is particularly vulnerable to flood damage.”

The research also found that 2012 flood mobilised large quantities of contaminated material from old mine workings and floodplain soils.  The majority of flood sediment samples were found to exceed UK and European metal thresholds for residential and industrial usage.  

Professor Macklin added: “Floodplain contamination in West Wales is a chronic and long standing issue, but it is a problem shared with other river catchments in the UK that have a history of metal mining.”

The report “Causes and consequences of a large summer storm and flood in west Wales 8th-9th June 2012” is published on Tuesday 23 October. A full copy of the document can be found by clicking on http://www.aber.ac.uk/fluvio-west-wales-floods-2012.

Its findings will be featured in Week In Week Out on BBC1 Wales on Tuesday 23 October at 22:35 and which will look specifically at the June floods in Ceredigion and the findings of this report.

The researchers completed this report as part of Aberystwyth and Bangor University’s Centre for Catchment & Coastal Research and Aberystwyth University's River Basin Dynamics and Hydrology Research Group.