New Manchester high-rise features new rain garden for sustainable urban drainage

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Manchester has received a new rain garden – an innovative and eco-friendly sustainable drainage solution – as part of the New Victoria development, which consists of 520 new homes in two 20- and 25-storey buildings.

The £185 million development, completed by VINCI Construction, is located on Corporation Street, adjacent to Victoria Station in Manchester. RSK Group company SCP Infrastructure was contracted to create the surface water drainage assessment and opted for a rain garden to harness vegetation and soil as part of the solution.

SCP Infrastructure Project Manager Jamie Larkin said: “Surface water runs into the garden and vegetation can soak it up. The remainder goes into the ground or, if this is saturated, is directed to a perforated pipe, which connects to a traditional drainage system.

“The rain garden prevents flooding in storm events by slowing the flow of water so the drainage network downstream is not overloaded. In addition to having a greater drainage capacity than traditional systems, it provides an area of vegetation at the front of the development that is not only visually appealing but also offers a small area of ecology – plants, flowers and insects.”

Jamie said that sustainable urban drainage systems serve as an alternative to gullies and pipes that are traditionally used to control rainwater and run-off.

“Rain gardens are designed to reduce the flow of water and as such cannot take excessive rainfall or water run-off like swales – shallow vegetated drainage channels – can. This is why rain gardens have a supplementary system that directs additional water to the traditional drainage system when the rain garden has absorbed all it can. Both rain gardens and swales are types of sustainable urban drainage systems that can be retrofitted into cities to assist with rainwater control while supporting biodiversity.”

Jamie said a similar solution using trees, known as a tree pit, was initially discussed, but the area and depth required for the trees’ root systems meant that the pit would encounter utilities, so a rain garden was proposed as a shallower alternative.

SCP Infrastructure Managing Director Steven Carmody said: “As far as we are aware, this rain garden is the first of its type in Manchester. We hope that this innovative drainage system feature will encourage the use of more sustainable urban drainage systems around the city.”