One of Green Action Trust’s (GAT) Landscape Architects designed an office raingarden and has transformed a derelict part of our carpark (where an old portacabin stood) into a biodiverse, plant-filled raingarden. The raingarden was installed in 2019, and provides us with a living lab to test out raingarden features, and see what works – and what doesn’t!
Move the slider to see before and after images:
Here’s two views of the Hillhouseridege raingarden from either end the main path, looking along the swale.
The diagram below shows the flow of water around the GAT raingarden. Rain falls on the roof of the barn and the workshop and downpipes take it down into the raingarden. It flows through different raingarden features, including a raingarden planter, a swale, and a basin. Some rainwater evaporates, some is taken up by plants, and some infiltrates back into the ground. An overflow in the corner of the raingarden can take water on to another pond in Shotts Nature Park.
Here’s a series of images showing you how the raingarden fills with rainwater at its eastern end, which has a more ‘urban’ feel with a downpipe draining to a channel across paving, and a shallow basin lined with slate.
Here’s a sequence looking from the western end showing you how the raingarden should fill up, depending on how much rain there is. However, we’ve found that because our swale is not lined, the rainwater seeps under the check dams and the raingarden fills up evenly across all the swales instead. If you are building a raingarden and have soil which has a high infiltration rate this would be something to think about in your design.