Gardens: the green line of flood defence

Climate change isn’t just about higher temperatures and heatwaves.

Garden in the rain

In her article (09/09/2023) entitled ‘Rain gardens offer a first green line of flood defence‘ in the Financial Times, Sharon Smith looks into how garden designers are adapting gardens to cope with the recurring and heavier rainfall we are experiencing. According to Met Office data, this year the UK had its sixth wettest July on record (wettest since 2009), with 70 per cent more rainfall than average.

Smith looks into to reducing run-off by building rain gardens and stormwater planters, and reducing hard landscaping, including incorporating plantings in patios and terracing. ‘On July 4 2021, the Edinburgh site of Royal Botanic Garden Edinburgh had a month’s worth of rain in less than an hour. Paths were eroded, compost was washed out of flower beds and plants were flattened‘, she writes. According to Smith four gardens at the RBGE are adapting to climate change by upgrading paths with porous materials and slowing down run-off emptying into drains. All of which are applicable to our own gardens.

In terms of planting rain gardens, Smith takes you through the various planting schemes that the RBGE are working on. ‘A rain garden typically absorbs 30 per cent more rain than a lawn. The RBGE rain garden measures 20m x 7m and has a depth of 450mm at its centre. Run-off pools in the middle then soaks slowly into soil that has been improved to enhance drainage. Plant roots take up some of the water and leaves intercept and slow rainfall. Plantings are a mixture of perennials and grasses that can cope with extreme conditions‘, she writes. 

An interesting article, explaining how the right mix of soil, plants and design can combat the wetter weather and sharper downpours brought by climate change.