BY KATIE - MYGREENPOD, 08 July '16

RHS Hampton Court Palace Flower Show winner demonstrates effective rainwater harvesting

Torrential rain and thunderstorms caused flash flooding in parts of London a fortnight ago and more heavy rain is expected to fall across the country in the coming weeks. In response to Britain’s increasingly wet summers, the RHS is calling on the nation to make efforts to conserve rainwater in our gardens to help mitigate flooding.

Gardens and flooding

At the RHS Hampton Court Palace Flower Show 2016 (5-10 July), sponsored by Viking Cruises, a Water Garden demonstrating ways we can use water run-off from buildings and paving to create wildlife-friendly water features in our own gardens was awarded Best Show Garden.

‘Some people don’t realise the massive role that gardens play in reducing the risk of flooding. Rainwater needs somewhere to go, so if it’s not soaked up or captured in some way, it’ll usually flow into street drains which can’t always cope with the thousands of extra litres in a storm so may result in flooding.’

GUY BARTER
RHS Chief Horticulturist

Working Wetland Garden

The Gold-medal winning ‘WWT Working Wetland Garden’, supported by the HSBC Water Programme and designed by Peterborough-based Jeni Cairns, encourages people to use rainwater to help minimise flash flooding, particularly in urban areas where paving, tarmac and concrete increase the amount of rainwater run-off by as much as 50%.

In the garden, water is collected from the roof which then passes through a cascading water feature where soil and plants slow down the water flow before it ends up in a wildlife pond. In periods of heavy rain the pond then overflows into an area of mini wetlands that holds the water before releasing it naturally and slowly.

‘Flooding is a big problem here in the UK so if you’ve got more grey than green in your garden come to the RHS Hampton Court Palace Flower Show where thousands of plants are sold every day. There are also plant experts on hand to help you select the best plants for your outside space. Come rain or shine, Hampton is a great show whatever the weather.’

DAVE GREEN
RHS Show Manager

The Water Gardens are making a comeback to RHS Hampton Court Palace Flower Show after an eight-year absence. This year they include Perennial’s ‘Immerse’ as well as the Scandinavian Garden from new headline sponsor, Viking Cruises.

Guy Barter’s 12 flood control tips

1. On its own one garden with opportunities for rain to soak in or be temporarily held rather than flowing into the street might not make much difference but together many gardens optimised to retain rain water will greatly reduce sudden floods.

2. Rainwater can be collected from the roof of homes, garages, greenhouses and other garden structures as long as they have gutters and a drainpipe – even in dry areas, 24,000 litres fall on the roof of an average home each year.

3. Local councils, water companies and DIY stores are often good places to purchase basic affordable plastic water butts.

4. When watering the garden use water butts first so there is capacity to collect water in summer downpours.

5. Plenty of tall vegetation especially hedges and trees catches water in summer on the leaves from which much evaporates before it reached the soil.

6. Trees especially dry nearby soil which can then gulp up heavy rain particularly in clay soils where fissures appear in the soil that soon fill with water.

7. Avoid leaving soil bare – it compacts under heavy rain and run-off occurs often taking valuable top soil with it. Instead cover with mulch or sow with a speedy green manure crop such as mustard.

8. Containers, even hanging baskets, absorb water each time it rains and covering as much as is convenient of the patio with container plants will go far to reduce run off.

9. Use porous paving options where water could run off into the street, with in the case of gravel, plastic or concrete reinforcing cell units to keep the gravel in place and spread the load.

10. Allow pond levels to fall in dry periods (with proper care for the welfare of any fish) so they can take up subsequent heavy rainfall.

11. Planted or green roofs can also absorb water. Sheds and other small structures are relatively cheap, practical and easier to ‘green roof’ than bigger buildings.

12. Monitor weather forecasts and avoid watering before rains. Rain won’t soak into saturated soils and is likely to run off possibly in damaging ways. And you might be able to save a job if the rain is heavy enough to do your watering for you.

Click here to buy tickets for the RHS Hampton Court Palace Flower Show 2016.