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Storm Water Tanks
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Rills
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A Rain Garden
Water, Water Everywhere
We have just seen the wettest winter on record. Gardens have suffered and in some cases been destroyed. We are fortunate that we live in a hilly region and so the risks of flooding on the scale of those in Somerset are reduced. However, we still need to be aware of flash floods and design our gardens to be able to cope with massive amounts of rainfall.
All of this water has to go somewhere. It can either go straight into the drains, which can easily become overwhelmed and cause flooding, or we can try and keep as much as possible in our gardens where we can manage where it goes and it can drain away without causing harm. This goes under the umbrella term of Rain Gardens and there are a series of ways of designing what is called the Storm Water Chain.
This is an example of how it can work. Each element is designed in such as way as to overflow into the next whilst still absorbing water and slowing the rate of flow.
• Rain falls onto roofs and hard surfaces which cannot absorb it.
• One option to start the chain is to install a green roof.
• From here it is fed, either via the down pipes or a rain chain, into a Storm Water Planter which is essentially an above ground waterproof bed designed to hold water for about 2 – 6 hours. This overflows into
• Rills. Shallow channels which will send the water towards a
• Filter Strip. A gently sloping area, either a lawn or planted but with a gravel filled trench along its top edge. This will spread the water out into a sheet & will slow it down. From here the water can be collected in a
• Swale or planted hollow. A long narrow depression no more than 60 cm wide. If this also overflows the water can be fed using more rills into one of the final elements of the chain, a
• Retention Pond. This will mimic a natural wetland and the water levels will fluctuate throughout the year. Only if this overflows might you need to direct the water into the drains.
There are many plants that can survive occasional submersion, some suggestions include: Astilbes. Echinacea purpurea. Miscanthus sinensis and Panicum virgatum grasses. Cornus sanguinea. Mahonia aquifolium. Alder, River Birch and Willows.
For more information contact colette@charsleydesign.com
t: 01803 722449. m: 07774 827799.
Follow me on Twitter @ColetteCharsley
First published By The Dart March 2014
