Specifier Review
Understanding Rainwater Harvesting

The Benefits of Rainwater Harvesting

With continual and rapid changes to our climate, the gradual increase in global temperatures and our ever exploding population, many countries across the world continue to experience a lack of water.

Mains potable water is a precious commodity that is ever under strain due to increases in demand from our rapidly growing population. In our own country the changes in weather and rainfall patterns have led to both drought and flooding.

It is highly likely that at some point in our near future the mains supply in many countries, including our own will not be able to meet the needs and increasing demands of our growing populations. Therefore with a little foresight more and more people are capturing their own water. Rainwater harvesting can provide nearly 50% of a family’s water needs, it saves water, money and reduces our environmental impact.

Architects, planners and builders are beginning to understand the importance of rainwater harvesting, allowing homes and houses to be more sustainable for the future.

Rainwater harvesting systems or RHS collect the water that falls freely onto the roof of your house. A rainwater harvesting tank can easily filter and store up to 6500 litres of clean water.

The RHS can be plumbed into your homes pipework and can be used for washing and toilets, thus reducing your water consumption by as much as 40%.

The Cloud House designed by Matthew Mazzotta is a unique harvesting system that we probably won’t see on a large scale in the UK!

The Cloud House - Understanding Rainwater Harvesting

On rainy days, a gutter system collects rain that hits the roof and directs it to a storage tank underneath the house. Sitting in the rocking chairs triggers a pump that brings the collected rainwater up into the ‘cloud’ to drop onto the roof, producing that warm pleasant sound of rain on a tin roof. At the same time, rainwater drops from the tops of the windows onto the edible plants growing in the window sills. Designed to collect and store rainwater for the ‘cloud’ to rain, at points throughout the year when there is low rainfall, the ‘cloud’ will not rain on the roof because it is simply out of water.

Understanding Rainwater Harvesting - Concave Roof

In many countries throughout the world water scarcity is at the forefront. Iran based BMDesign studios created an architectural solution to water shortages, called Concave roof.

The design involves a double-roof system designed to collect and store rainwater. It has been engineered with higher than average evaporation rates and low precipitation.

The double roof system which includes a domed roof beneath a bowl shaped catchment area has been designed to allow even the smallest quantities of rain flow down the roof and eventually gather into larger drops. Stacking a concave roof atop a convex roof also promotes natural cooling along with shade and wind movement.

Rainwater Harvesting - Sustainable Market Square

TomDavid an architect based in the Netherlands has designed a sustainable market square for the crowded and polluted central areas of Morocco. The design incorporates both the capture of rainwater along with the redirection of waste.
This clever design, which features an elevated platform shaded by a leaf-shaped canopy and underground shopping, promotes greater ventilation and human circulation and fosters a more sustainable market ethos.

Water that either pours or trickles off the canopies is harvested and stored in underground containers that supply the necessary water for the square’s plumbing or to clean the pavements. This process can be used to accumulate and store the water with the intention of reusing it throughout the dry season or during times of drought. Rainwater Harvesting is clearly of the hour and will continue to be for the uncertain years ahead. Rather than reading about it, maybe it’s time we did it.