Rainwater Harvesting & Run-off Control for More Sustainable Landscaping

In part 1 of this series, we talked about how we can conserve water resources in landscaping, particularly as our climate becomes warmer and drier. But as an island nation, we still have sufficient rain to maintain a ‘green and pleasant land’ if we can find ways of storing it for future use. Sometimes we simply have too much of it and flooding is a problem.

In this article, we will discuss how rainwater can be harvested and stored for future use. We will also look at how we can mitigate the effects of heavy rainfall to reduce flooding risk and retain more water in the soil.


Storing water - from butts to underground tanks

The roofs of our houses collect a tremendous amount of water during the course of the year; all good, clean rainwater that is far better for plants than tap water. And the traditional water butt is a common feature of many small- to medium-sized gardens. Converted from old oak barrels or moulded in modern plastic, these can only hold a fraction of the water that the roof sheds in the rainy seasons and will soon run empty in a dry summer.

Many commercial and large-scale gardens realise the value of rainwater harvesting as it reduces their metered water bills, and have installed large tanks to harvest the water from the roofs of buildings and greenhouses. The larger of these tanks are made from sectional steel, with medium-sized versions made of durable plastic.

If a large, cylindrical tank is too unsightly for your location, slimline rectangular water tanks are designed to tuck unobtrusively into small spaces next to garden sheds or behind screens. With capacities of up to 1,000 litres, these can hold four times as much as a standard domestic water butt.

If 1,000 litres isn’t enough for you but you don’t want an eyesore, consider investing in an underground rainwater storage tank – these vary in capacity from 1,500 litres to a whopping 5,800 litres and can be incorporated into a landscaping design with almost zero visual impact.

Whatever the size of your garden, landscaping project or budget, investing in rainwater harvesting will help you secure water for your future needs

green roofs

Reducing flooding risk – green roofs

Even with a large rainwater harvesting system in place, it’s impossible to capture all the water that falls on our roofs. If there’s a particularly heavy downpour the roof will shed water too quickly for the gutters to cope and when a water butt or storage tank is full, all excess water will be diverted back to the storm drains. When the storm drains overflow, flooding occurs.

One solution that is gaining popularity is green roofs. Suitable for use on pitched or flat roofs, a green roof serves many purposes including reducing urban temperatures, regulating the temperature inside buildings, increasing biodiversity and, of course, slowing down the rate at which a roof sheds rain.

A green roof is like an enormous sponge, soaking up water during rainfall and then slowly releasing it at a rate that guttering systems can manage.

Green roof technology can also be used to create attractive features such as flower beds, shrubberies and lawns on a roof garden or terrace high above the city streets, where residents and office workers can take a break in calm, natural surroundings.

RoofEdge is a galvanised steel landscape edging product designed and manufactured by Kinley specifically for green roof installation. This innovative product is easily installed on all types of green roofs, roof gardens and terraces, providing a durable, low-maintenance barrier between soft and hard landscaping.


Reducing flooding risk – permeable paths and drives

Paths and drives serve both aesthetic and practical purposes in landscape design, drawing the eye and leading us from one feature to the next while keeping our shoes clean and dry, giving places for vehicles to pass or park and preserving the beauty of the soft landscaping.

But many materials used for paths and drives are poor at retaining water. Solid concrete and asphalt will shed water immediately while the gaps between stone, brick and concrete slabs and blocks will only absorb a limited amount of water.

Gravel is a good alternative for paths as water can quickly pass through it and be absorbed into the earth below, although loose gravel on lawns can wreak havoc with lawnmowers and other garden maintenance machinery.

Metal landscape edging is very effective at holding the gravel in place and preventing earth, mulch and lawns from spreading onto the path. As we mentioned in the previous post, it also has better sustainability credentials than timber and concrete edging.

Another surface that is gaining rapidly in popularity is resin-bound aggregate. Primarily used for driveways, this provides a hardwearing, low-maintenance surface with much of the appearance of fine gravel or asphalt. It is also a permeable surface that allows rainwater to percolate through to the ground below, so is an ideal candidate for anyone looking to reduce water run-off.

ResinEdge is a heavy-duty extruded aluminium edge restraint developed exclusively for use with resin-bound paths, driveways and recreational areas. It is also available as rigid or flexible edging, so arrow-straight lines and spectacular curves can be created to faithfully follow the landscape’s design.


This is the second in a three-part series on sustainable landscape design. Other posts in the series are:

Part 1 can already be accessed using the above link. Look out for Part 3 in the coming weeks!

We hope you are finding this information helpful and interesting, and if you would like to find out more about aluminium and steel landscape edging, call the friendly team of experts at Kinley on 01580 830688 or email sales@kinley.co.uk.