By Huw Morgan
People and Wildlife Officer Brighton
Rain Gardens are on the rise, here in the Brighton & Lewes Downs Biosphere following the evolution of this pioneering concept in the US and Sussex Wildlife Trust Youth Ranger group in Brighton have been busy building the first examples in the city.
A “rain garden” is simply a low-lying area of ground containing plants tolerant of wetter conditions that is designed to receive and retain rainfall from surface water run-off from hard surfaces, and then slowly drains away over time to leave them without any open water for most of the year.
This natural way of helping to alleviate local flooding is a form of ‘green infrastructure’, that works in combination with the conventional grey infrastructure systems of drains, pipes and sewers.
Rain Gardens are a type of Sustainable Drainage System, or ‘SuDS’, that can be created both in existing green spaces and as new elements of urban development, to help to reduce flood risk from heavy rainfall events – an phenomenon that is increasing with climate change.
The great thing about Rain Gardens is that they not only hold back storm water and reduce flooding, but they can also help to filter pollution, attract wildlife to your neighbourhood and look colourful at the same time – making them multi-functional in nature. ‘
The idea of rain gardens since spread to various cities across the US, most notably Portland, Oregon, where the city’s chief landscape architect Tom Liptan championed the idea, initiated various trials and produced guidance that allowed citizens to get involved by creating rain gardens in their own gardens or on adjacent verges. Tom emphasized the importance of multi-functionality, with rain gardens being promoted as attractive landscape features in their own right, as well as being drainage features.
Now the rain garden concept has a foothold in the UK, with a few projects around Stroud, in South Wales, London and now in Portslade as part of the Brighton & Lewes Downs Biosphere programme of environmental improvements.
The idea of the two new rain garden pilot schemes now established at Lockshill (Portslade village green) and Victoria Recreation Ground is that surface water runoff is re-directed into small basins or ‘swales’ from which it can slowly infiltrate into the underlying chalk or evaporate or transpire through plants later. These features in Portslade have also presented an opportunity to create two new wildlife habitats, by planting local wild flowers in to the chalk banks and seeding the damper hollows with wetland plants.
Although these new rain garden pilots are relatively small-scale, we hope that they will be the forerunners of many similar schemes in the Biosphere in the future, to help to reduce flood risk whilst bringing more nature to town. Such natural benefits are vital to sustain our urban quality of life and help cope with the effects of climate change.