Increasing numbers of households are facing the bleak possibility of flooding in the future. The Foresight Future Flooding report - published in 2004 by Chief Scientific Adviser to the Government – predicted that flood risks will grow to unacceptable levels in every considered scenario. That prediction is evolving into fact, as flooding has become more common over recent years:
- 2012 - 8,000 homes flooded
- 2013 to 2014 - 11,000 homes flooded
- 2015 to 2016 - 17,000 homes flooded3
Check if you’re at risk
RHS research into flooding
The positive news is that home owners can take action to mitigate the risks to their property - and gardens could be part of the way forward. RHS Prinicipal Scienctist, Tijana Blanusa, whose research interests lie in understanding the intereraction between plants and the environment, runs several projects investigating the contribution of greenery to the moderation of temperature, capture of rainwater and pollutants.
"It's possible to reduce the impact of a flood at your home by using flood resilience measures. You can never eliminate the risk of flooding entirely, but you can reduce the risk of water getting into your home," she said.
What can I do to reduce my flood risk?
Tijana's research suggests that the following actions may help:
1. Remove 'sealed surfaces' and plant something
A quarter of all front gardens are completely paved over. Removing greenery and covering soil with impenetrable surfaces are the main causes of increased flood risk4.
"You can improve everywhere by planting something – anything is better than retaining sealed surfaces," said Tijana.
Plants help by intercepting rainfall and delaying the moment the rain hits the ground - taking pressure off public drains. Plants also take up water from the soil and return it to the atmosphere (a process known as evapo-transpiration) this allows the soil to absorb more rainfall.
2. Plant evergreen hedges for year-long benefits
Hedges are popular features in domestic gardens and worth keeping in preference to fences. You could also consider planting some evergreen hedges which are in leaf all year. In winter, when there are no leaves on the deciduous trees and hedges, the presence of evergreens is invaluable to retain and remove rainfall.
Recent research into "the benefits of different plant types on the environment" suggests an advantage of evergreen species due to a year-round provision of flood protection5 but also various other benefits including noise reduction, providing biodiversity and air quality improvement.
3. Grow a variety of plant types
Different species are more effective in taking up and intercepting rainfall at different times of the year.
Hawthorn, for example, was found to remove rainfall in summer, but when dormant in winter was less effective than mixed evergreen planting.
RHS report on hedges to meet urban challenges
More shrubs that thrive in damp soils
Follow Tijana’s tips and you won’t just minimise your flood risk you’ll also improve local air quality, encourage wildlife and ease stress for yourself and others.
More RHS advice on mitigating flood risk
Read the Government’s guidance on creating a personal flood plan
4. Perry T, Nawaz R (2008) An investigation into the extent and impacts of hard surfacing of domestic gardens in an area of Leeds, United Kingdom. Landscape and Urban Planning 86 (1):1-13
5. Blanusa T, Hadley J, Hunt L, Alexander P, Hobbs K (2018) Provision of ecosystem services by hedges in urban domestic gardens: focus on rainfall mitigation. Acta Horticulturae, 1189. pp. 519-523. ISSN 2406-6168 doi: https://doi.org/10.17660/ActaHortic.2017.1189.104