New Glasgow Flood Defences Pass Their First Test

White Cart Water Flood Prevention Schme

Just four weeks after the White Cart Flood Prevention Scheme had its official inauguration, new flood defences successfully held back rising water and helped protected hundreds of homes and businesses within Glasgow.

Heavy rain and wind at the end of November caused flooding across many parts of Scotland.  Officials at Glasgow City Council said that all the defences were monitored throughout the flood threat and they worked extremely well during the storm.

It is estimated that nearly £11 million of flood damage would have been inflicted on homes and businesses in the south side of the city without these new defences.

The world’s largest ever Hydro-Brake® Flow Controls are central to the £53 million White Cart Water Flood Prevention scheme, designed to protect 1,750 properties in the south of the city from the risk of flooding.  The Hydro-Brake® Flow Controls constructed in three dams are designed to hold back water in three flood storage areas upstream of Glasgow, which together have the capability to hold back millions of gallons of floodwater generated by extreme rainfall.

Gordon Matheson, Leader of Glasgow City Council, said: “This was a major test for these new flood defences since its inauguration and they have passed with flying colours.

“This was a major investment and commitment by the council to protect homes within the south side of the city. I am sure that these new defence have brought huge comfort to local Glasgow residents and businesses that heavy rains now won’t cause havoc and flooding to their properties.”

During the last days of November, the three reservoirs held a total of 237 million gallons of flood water, the same amount as approximately 350 Olympic-size swimming pools – which is about 43% of the total storage volume.

Manufacturer Hydro International had to pioneer new manufacturing and installation techniques to construct the eight-metre long, six metre-high, cone-shaped Hydro-Brake® Flow Controls which were positioned in dams at Blackhouse and Kittoch.  A further three Hydro-Brake® Flow Controls were installed in the dam at Kirkland Bridge.   With a combined stainless steel weight of more than 60 tonnes, all five are the biggest ever produced.

Normally, a shallow, fast-flowing river, White Cart Water is prone to flash-flooding and water levels can rise by six metres after only 12 hours of rain.  Since 1908 it has inflicted more than 20 serious floods on homes and other properties in the south side of the city.

Scotland’s largest confirmed flood prevention scheme has been designed by consulting engineers Halcrow on behalf of Glasgow City Council.   During peak storms, the Hydro-Brake® Flow Controls hold back the White Cart Water and its tributaries Earn Water and Kittoch Water causing the storage areas to flood.  Water is released downstream at a controlled rate so that it does not overspill new flood defences being constructed in the city.

Since Hydro International developed and pioneered the Hydro-Brake® Flow Control’s unique vortex technology 30 years ago, it has become an industry-standard method of flow control.  Most frequently used in much smaller dimensions as part of urban surface water drainage designs, the Hydro-Brake® Flow Control’s internal geometry is designed to enable water to flow through unrestricted for as long as possible.  A self-activating vortex is created when the water reaches a pre-determined height, for example in a flood situation, holding back the water, and releasing it at a measured, controlled rate.

The new flood storage areas are at Blackhouse (Earn Water) in East Renfrewshire, Kirkland Bridge (White Cart Water) and Kittoch Bridge (Kittoch Water).

The White Cart, which rises near Eaglesham in Renfrewshire and flows six miles through Glasgow’s south-side, is a shallow and fast flowing river making it prone to flash flooding. Only 12 hours of rain can raise water levels by 12ft which has the capacity to affect many hundreds of properties along the course of the river.

As well as the new flood storage areas, the scheme also includes new flood defences downstream including five miles of new embankment walls.

The fully operational scheme gives those living along the White Cart and its tributaries peace of mind and provide protection from an up to a 1: 200 year storm.

The scheme is also supported by the Metropolitan Glasgow Strategic Drainage Partnership (MGSDP). This is a unique partnership formed by organisations involved with the operation of the sewerage and drainage network in the area including Glasgow City Council, Scottish Water, Scottish Environment Protection Agency, the Scottish Governments and British Waterways. The overarching aim of MGSDP is to provide a holistic approach to managing surface water which will reduce flood risk and unlock development potential while improving water quality and allowing residential areas to co-exist with the natural landscape. The website is www.mgsdp.org

Read more about the White Cart Flood Prevention Scheme.

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