If you live in an urban or built-up area, you might have already noticed the urban heat island (UHI) effect, where your locale is significantly warmer than the outlying rural areas.
This phenomenon is the result of higher levels of human activity, with heat created by energy from all the people, buses, cars and trains in big cities, as well as close construction of all the buildings and modern insulation materials holding in the heat.
Dense populations and necessarily dense construction mean that the expansion of urban areas takes place in an upward direction, with waste heat having nowhere to go, lingering instead in and between the buildings, trapped on lower levels with nowhere to go.
This then leads to issues like poorer air quality, pollutant buildup and poorer water quality – but the good news for those living in cities is that you can design your way around the UHI effect at home.
For example, you can keep your urban gardens cool by creating areas of shade through vertical layering of trees, plants and shrubs. Doing so will drive transpiration processes, with plants releasing water vapour to lower temperatures, similar to how natural woodland works.
Your choice of landscaping material is also paramount if you want to reduce the UHI. Using lots of materials like concrete, brick and hard paving means that the UHI will be increased, because these are all heat absorbent. Instead, opt for the likes of gravel and clay, both of which are permeable and can help drive down surface temperatures.
Similarly, consider using lighter colours throughout your garden spaces so that light is reflected rather than absorbed, reducing heat accumulation.
And finally, look into introducing various water features like ponds and fountains to help your gardens cool down. The added benefit of this, of course, is that you’ll support local wildlife and biodiversity – so it’s a very real win-win!