I was very excited to visit the raingarden in the Botanic Gardens of Edinburgh with the CIRIA Susdrain Group. The staff from the Botanic Garden explained how they had a problem with surface water flooding and, after some tests and investigation, they decided to excavate an area to create a rain garden to capture and hold some of the surface water. The soil tests were uninspiring and suggested that infiltration wasn’t going to be very effective, so they blended some other materials into the soil on site to improve infiltration rates. Surplus soil was used to create a berm to protect the footpath and, rather conveniently, to create a raised dais for us all to stand on as we learnt about the design details. Some of the local students are carrying out research on the rain garden to understand the effects of evapotranspiration and leaf cover, amongst other things, and we look forward to see what they learn.
The planting included some magnificent large-leaved plants alongside native flowering plants and as we stood there, we could see loads of flying insects enjoying the Scabious flowers. It is a beautiful place, that is loved by the wildlife, at the same time as being a magnificent SuDS feature. And there was just a little hint of Jurassic Park!
Jo Bradley. Director of Operations
