Caption: Kims Climate Change Garden in West Wales
Caption: Kim allowing wildlife and Weeds into her swale to provide flood protection
In an extract from the Dalefoot sponsored, The Climate Change Garden Book, co-author Kim Stoddart explains how to better protect your garden from flooding...
As Cop 26 brings awareness to the on-the-ground importance of environmental action around climate change, many parts of the country are mopping up after a weekend of heavy rain and storms. In the UK an estimated five million homes in the UK are at risk of flooding and with the predicted rising sea levels, and greater extremes of weather, unfortunately flooding is going to become more commonplace. It already is.
In the garden, compost rich soil is better able to hold and absorb a greater excess of water, so making your loam the best it can be is always a help all year round for natural resilience and vitality from the ground up. Working with perennials, which have deeper root structures and can help soak up rain, using ground cover over winter and not digging your soil are all incredibly important actions to take for our whatever-the-weather future.
In a natural ecosystem, most of the rainwater soaks into the ground. While some is taken up by plant roots, most continues downward to the water table. The water is filtered through the rocks, so clean water recharges the water table. But, in gardens, hard landscaping and other impermeable surfaces mean that the water cannot soak into the ground so it has to flow elsewhere. To stop your garden from flooding you need to slow down the movement of water, giving it the chance to soak into the ground or flow gently into local water courses.
Slow it, spread it, sink it. Here’s how:
Work together with neighbours
It’s surprising just how much difference a group of neighbouring gardeners can do to reduce flood risk, so work together. Joint actions might include collecting rainwater by using water butts, avoiding bare patches of soil, directing water away from neighbours’ gardens, to reduce the amount of water leaving one garden and entering that of a neighbours. And a really simple, but effective, idea to trap and slow down water is for everybody in the street to simply put a load of buckets on their deck or patio to catch water. They can empty them gradually after the rain has stopped or use them to refill water butts.
Slowing down water
Slow water means encouraging water to move into the soil and reducing run off and there are lots of ways you can improve the flood resilience of your garden by incorporating clever slow water features in your garden.
1. Mulching Spreading a thick layer of compost over the soil each year will boost soil organic matter and create a permeable surface that water can penetrate and drain through. Bare soil can be surprisingly impervious as the impact of water droplets on soil creates a barrier, so don’t leave bare soil. Instead, mulch it with compost, cover it with plastic or grow a green manure. Trees are useful too, as their roots absorb water from over a large area, so a garden with trees and shrubs can absorb more water than the same area of garden without trees and shrubs.
2. Raised beds can be incredibly useful in gardens where water collects. The advantage of a raised bed is that it lies above the water level, so the soil does not get waterlogged.
3. Avoiding large areas of concrete and other impermeable surfaces is important as they create a lot of run-off. Instead, use paving stones, bricks or gravel so that water can seep through the gaps.
4. French drains and weeping tiles A French drain is a small trench that is backfilled with gravel. It allows water to drain away from a building, driveway or lawn, stopping water from collecting and reducing the risk of flash floods. To improve the flow of water further, a perforated drainage pipe known as a weeping tile is laid along the bottom of the trench to help carry water away from the house to an area that can cope with the water or to a soakaway. Weeping tiles were once made from terracotta but nowadays they are plastic.
5. Water butts and storage tanks are great for harvesting water for use in the garden in summer but, once they are full in winter, they are no help at all in slowing down water. After a storm, when they are full to capacity, it is best to let the water drain away gradually so that, when it rains again, they can collect a large volume of water. Make sure the valves are closed from April onwards so you have plenty of water for summer.
6. Swales and berms Swales are ditches that are built along the garden contours and are physical barriers to slow down the movement of water and runoff. The raised bank beside the swale is called a berm and they work together to slow run off, with the swale filling with water and slowing down its movement. Swales can be built so that they direct water to a soak away, rain garden or storm drain.
About the Climate Change Garden Book
Kim is the co-author of The Climate Change Garden book with Sally Morgan, the essential guide to all things climate change savvy growing in our changing climate. www.climatechangegarden.uk
About Kim Stoddart
Kim has been writing in the national press on climate change gardening since 2013 in publications such as The Guardian. She has regular columns in Country Smallholding and Grow Your Own magazines and edits The Organic Way magazine for Garden Organic. Kim also runs in-person and online courses on resilient growing via www.greenrocketcourses.com