Is Climate Change The Reason for the Westlink / Broadway Flood?

At the weekend during "freak" weather conditions, parts of Northern Ireland received in excess of August's rainfall in under 12hrs, leading to extensive flooding across the province, which lead to 850 calls to emergency services, and over 8000 calls for assistance from public service providers such as the Department of the Environment (DoE), Road Service NI, and Northern Ireland Water. Since I had not posted since Saturday, I'm sure you may have even thought I was stuck somewhere.

However, one iconic part of the road network in Belfast was left submerged in 20ft of water, capturing in excess of 20 million gallons of water. The Westlink and M1 upgrade scheme began in February 2006 at a cost of around £104m in a bid to solve the problems of daily rush-hour bottlenecks. The underpass was opened to traffic six weeks ago — 13 months ahead of schedule — and was designed to improve the strategic links between the M1, the M2 and the M3 motorways.

The Broadway roundabout underpass has two live rivers that run beside it, the Clowney Water to the west, and the Blackstaff adjacent to the east. These rivers are underground and therefore have a fixed capacity. Despite the construction of a large overflow chamber under Broadway roundabout. The design shape of the Westlink is effectively a basin or bowl which would funnel any water to the centre, this water would then drain away, making use of the overflow chamber. In the days preceding the "extraordinary event", there had been continued rainfall, this saturated the area which was worst affected, leading to the ground being unable to absorb any further rainfall. Rain then lay, or in the cases where it fell on uneven ground ran to the lowest point. This increased substantially the amount of water in rivers, and water from previous days were still filtering downwards. At the Clowney Water and Blackstaff, where the capacity is fixed, water could only pass through at normal rates, or increased rates at increased flow, so to cope with twice as much water, the river would have to have passed at twice normal speed, it can to a certain degree cope until no more when the waters will back up an eventually force the rivers to burst their banks.

This month has been the wettest August on record, with 177.8mm of rainfall so far. The last wettest August was in a 1956 with 161mm of rainfall. So how could climate change or global warming be to blame?

Research from Newcastle University in 2006 suggested that rain intensity has doubled in the UK over the last 40 years due to climate change, this has an affect on current systems which may have been designed to cope with large amounts of water over long periods, however as rainfall becomes heavier and more intense, these systems have to cope with the same amount of water but in a shorter time frame, as on Saturday; existing systems simply could not cope.

"If the trend continues, which is likely, this suggests we will have an increase in flooding over the coming years which has major implications for flood risk management"
Dr Hayley Fowler, Newcastle University

This may not be the last time that the Broadway underpass becomes submerged, holding the equivalent water of 32 Olympic swimming pools as the area flooded previously in December 2007, and that was before the underpass had been dug out, it's now only a matter of time and alot of intense rain before it happens again. Floods can also be exacerbated by plastic bags. Bangladesh, imposed the ban after it was revealed they were a major contributor to the 1988 and 1998 floods which submerged two-thirds of the country.

There is a great deal of sympathy for those who have been affected by the recent events, its hard to contemplate that it may be months or even a year before homes will be returned to normal, and the loss of irreplaceable items.

For those disposing of destroyed white goods and electronics, you should contact the council for a free household amenities collection. When replacing white goods, consider purchasing the most energy efficient appliances.



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Photos
Belfast Telegraph (2-5)