Civil Engineers develop solution for urban flooding
Anyone who has found themselves up to their ankles in water outside the shopping mall will appreciate the growing problem of urban flooding.
Downpours intensified by climate change have seen streets awash in non-traditional flood areas like Bootle, St Helens and Didsbury in the last year alone.
So how can we better channel urban rainfall in our increasingly concrete jungle towns and cities?
One innovative approach has seen Liverpool John Moores University create a combined-separate sewer system, which is suitable for narrow urban streets.
Tested at full-scale prototype at the Institute for Underground Infrastructure (IKT) in Germany, LJMU’s School of Civil Engineering and Built Environment and AB Infrastructure Ltd claim they can channel both foul and rainwater more effectively and create underground ‘sinks’ for excess storm water.
Space-efficient
They say it addresses disruptions to city streets and flooding events in downstream networks by mitigating the flow energy inside the storm chamber and enabling separate sewer pipes to be accommodated in one trench.
Dr Iacopo Carnacina, a reader in water and environmental engineering, said that initial tests of the system were very encouraging.
“The aim is to eliminate the problem of combined sewer overflow and increase the retention of storm water in the system. This will go some way to alleviate flooding in urban streets and overload in receiving water bodies,” he said.
The new manhole consists of an inner shaft for wastewater and an outer section that carries the storm water, enabling separate sewer pipes to be accommodated in one trench.
Narrow streets, hilly towns
“The design would be especially advantageous in narrow streets, which are common in many urban areas worldwide, particularly in hilly regions.
“Finding space for a traditional separate sewer system in these neighbourhoods is often challenging if not impossible.
“Our solution not only helps solve the space issue but reduces the initial construction cost and time.”
Dr Abbas Alaa, director of AB International Ltd says sewerage systems in many urban areas have frequently not changed in 100 years.
“Effectively what we’re doing is combine separate sewerage systems into one integral structure with two non-communicating internal chambers, allowing stormwater and foul sewage flows to pass through the same manhole without mixing.
“We believe it is better suited to addressing current challenges in terms of climate change adaptations and avoiding the issue of increasing floods, especially in downstream sections of hilly regions.”