Urban climate resilience is imperative. With more people living in urban areas, there is a reduction in urban living space for residents. Alongside this, climate change is having an increasing impact and therefore needs a much greater focus in urban planning. The high threat combined with high populations in urban areas means that planners and engineers must respond with more efficient means of living. In this article for Sustainable Cities and Society, four Pillars were identified to address the challenges of urban resilience: resistance, recovery, adaption, and transformation. It has been suggested that the way in which cities have been built since the 1950s is unsustainable and therefore, a more sustainable urbanisation approach is needed.
Risks
Future-proofing our cities from natural disasters is a key part of building urban resilience. Extreme weather patterns are becoming a more frequent occurrence. This includes an increase in warmer temperaures, as seen in the 2022 heatwave, rising sea levels, and an increase in heavy rainfall. Cities have not been designed to withstand such events and therefore, structural resistance needs to be at the forefront of urban planning.
Urban living
Forum for the Future predicts that more than 70% of people are estimated to be living in urban areas by 2040 despite a decrease in living space within urban cities. Globally, urban areas provide some aspects of attractiveness, Typically, living within urban areas coincides with improved living standards. As evidence shows there is better access to improved sanitation, improved drinking water, and clean fuels for cooking and heating . On the other hand, the urbanisation of new developments is having a detrimental impact on these benefits. The Committee on Climate Change stated that in the past five years over 570,000 new houses have been built that are not resilient to future high temperatures.
Blue-Green Infrastructure
With urban living problems becoming more prominent, infrastructure is needed to tackle these issues. Flooding is one major issue that infrastructure is aiming to tackle. One in six properties in England are at risk of flooding from rivers or the sea and a further 2.8 million properties are susceptible to surface water flooding alone.
Blue-Green infrastructure (BGI) is a solution to enhance climate resilience and a type of sustainable urban drainage solution (SuDS). BGI is a nature-friendly way of managing urban flood-risk through interconnected networks of natural and designed landscapes. This could include green roofs, retention and detention ponds, swales, infiltration trenches, retention basins and rain gardens. Blue Green infrastructure as a climate resilience solution also offers many additional benefits including improvements to air and water quality, aesthetics, and biodiversity.
The anticipated increase in heavy rain events will cause issues with surface flooding. Open spaces and green infrastructure can assist in managing surface level flooding by slowing the flow and storing excess water. Green infrastructure can provide crucial flood risk management system.
Health Implications
Health implications are also very relevant to urban development. With less access to green space in urban areas, mental health and wellbeing are put at risk. In England, only half of people live within 300 metres of green space and this is expected to decrease in the coming years as urban infrastructure expands. This lack of access to green space is having adverse effects on mental health and well-being. With a sedentary urban lifestyle there is an association with physical and mental illnesses which in turn create increased economic and social costs. The NHS stated in their 2021 nature campaign that people spending two or more hours a week in nature experience better health and psychological wellbeing. This time spend outdoors reduces blood pressure and stress levels, leading to improved moods . With green space diminishing, this is becoming more difficult for people living in urban areas.
Optimising space
Typical SuDs components that can help to increase blue green infrastructure and provide important benefits of water quality, biodiversity, amenity and well-being include green roofs for source control, trenches for infiltration, detention basins, retention ponds, rain gardens, wetlands and swales. These features play an important role in filtering, slowing the flow and storing water. However, with space limitations mean that these methods do not always provide the required level of flood risk management alone. Maximizing nature-based solutions and combining with traditional or engineered stormwater management systems can’ provide the required level of surface water attenuation to mimimise flood risk whilst also providing a range of other benefits.
Wavin’s Contribution
Wavin’s stormwater solutions include a range of geocellular attenuation tanks which can be used for storage and controlled release of surface water. They can be used in conjunction with landscaped SuDs to provide an optimal solution that benefits water quality, biodiversity and space for amenity as well as managing water quantity and preventing flooding particularly in extreme weather events.
