Holding Back The Flood and The Urban Rain Garden

There is a new category of show garden at Hampton Court this year – ‘Gardens For A Changing World’. Each garden considers a challenge of our times and creates a design which will address the issue and offer solutions. Both The Urban Rain Garden and Streetscape’s Holding Back The Flood consider water management issues, exploring ways of conserving our precious supplies and preventing flooding.

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Will Williams has created an undulating flooded area around the alder trees

The youngest designer at the show, Will Williams (21) has created a symbolic garden which offers a way to prevent flood damage using alder trees (Alnus glutinosa) rather than relying on concrete barriers. The garden is inspired by the town of Pickering in North Yorkshire which was turned down for a twenty million pound grant despite its high flood risk.

Needing alternative options and drawing on research from around the world, the inhabitants instigated a scheme to plant thousands of alders and create leaky dams to slow down and even prevent downstream flood water. If such lower cost, environmentally-friendly and aesthetically-sensitive options prove successful, it offers a positive way to approach the model predictions of a 35% rise in winter rainfall and a 25% increase in daily rainfall totals in some parts of the UK by 2080 (source: The role of woodland in flood control: a landscape perspective).

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Although not a conventional ‘garden’, I loved the reflections in the water and the space they gave you to approach the design in your own time and on your own terms

Another community aspect to this design was the construction team – all from Streetscape’s team of landscape garden apprentices. As a social enterprise company, Streetscape provides apprenticeships for 18-25 year olds, helping them to build the skills, experience and attributes they need to fulfill their dreams, and move into and retain work. This must have been a complex build with 52,000 litres of water to contain and nine alders to plant, but it all looks effortless and peaceful, showing the calm beauty of this ingenious, age-old water management system.

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An alder sapling establishing itself

As well as its beauty, the woodland approach to water management also scores highly on sustainability. Will has included miniature saplings around the garden to show how the alders would gradually spread to create a self-supporting ecosystem. The alders can survive up to three weeks submerged in deep water and even longer in boggy ground whilst the flooding recedes. As our climate changes over the next few decades, the research undertaken by organisations like the Forestry Commission, flood prevention schemes such as the one in Pickering, and gardens like Will William’s all help to investigate practical solutions to an increasingly important issue.

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Will Williams enjoying the garden after a challenging build

The Urban Rain Garden also offers solutions to flash flooding, but this time within a domestic setting. I liked the realistic scale of the front and back gardens in this design – allowing visitors to imagine how the raised borders might work in a real setting.

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The back garden is bordered by beautiful raised beds with a hidden water management purpose

Designer Rhiannon Williams completed her Masters Degree in Landscape Architecture last year and has a keen interest in the subject of sustainability and water management. She explained that she designed the raised planters to step down in order to take water away from the house. As the water drains from planter to planter, the moisture levels reduce and the planting reflects this.

The water runs off the roof via downpipes and metal chains

In the planters nearest the downpipes, Rhiannon has included marginal plants such as corkscrew rush (Juncus effusus), rough horsetail (Equisetum hyemale), arum lily (Zantedeschia ‘Crowborough) and Apache beads (Anemopsis californica) which cope with raised water levels in periods of flash flooding.

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Water then drains from planter to planter

As the planters continue and become drier, the planting changes, moving from hostas (‘Devon Green’ and ‘Purple Heart’) to brighter perennials like sea holly (Eryngium ‘Big Blue’), Agapanthus ‘Navy Blue’, Salvia ‘Caradonna’, ‘Blue Note’, ‘Amistad’ and ‘Ostfriesland’, and Achillea ‘Anthea’.

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Mixed perennial planting towards the end of the garden

In times of heavy rainfall, water reaches the end of the bed system and drains into a tank beneath where it can be stored to use in future times of drought. In this way, the garden addresses two key issues which are likely to become even more important over the next few years – flooding and drought, offering practical solutions in a realistic garden setting.

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The planting also proved popular with the pollinators

Holding Back The Flood and The Urban Rain Garden demonstrate ways in which gardeners and communities can use innovative, practical water management techniques to deal with flooding and drought. In a world where we increasingly need to address the challenges posed by climate breakdown, ‘Gardens For A Changing World’ offers new ideas and solutions to give us inspiration for the future.

If you’d like to read more about the RHS Hampton Court Gardens, my other articles include:

London Glades: Forest Garden Solutions For Urban Spaces at RHS Hampton Court Flower Show

12 Practical Ways To Create A Modern Kitchen Garden

and you can follow my blog below. Happy gardening  🙂

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6 thoughts on “Holding Back The Flood and The Urban Rain Garden

    • dogwooddays says:

      Yes, I think there are a lot of practical take home ideas, but the whole system would probably be quite expensive. Worth it though if your garden kept getting flooded!

  1. JudyBJudy says:

    I enjoyed the concepts of both of these gardens/water solutions.
    With the urban one, although I liked the planting, I was left a bit confused that it was completely paved front and back… isn’t gravel (if grass not practical) encouraged in urban settings to aid rain water drainage, and concreting or paving thought the worst option, and actively discouraged by the urban environmentists? I guess the buried tank would take care of flash rainfall up to a point, but in typical small urban terraces that’s a lot of heavy digging/soil removal… to where?

    • dogwooddays says:

      Maybe they were trying to appeal to the modern urban gardener who might like a contemporary style and want a paved section in the front garden to park on? I think the main central area in the back garden was grass, although there were steps and a patio. It’s not at all my kind of garden, I prefer altogether wilder spaces, but I suspect it was aimed to appeal to a sleeker, more modern generation than me!! 😊

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