Porous Urban Landscapes

A recent study conducted by Stockholm University has concluded that rainwater anywhere in the world is now too toxic to be safe for human consumption. Researchers discovered high levels of artificially synthesised toxic chemicals, known as perfluoroalkyl and polyfluoroalkyl substances (PFAS), in rainwater across the globe. Along with an increasingly unstable climate and increasingly unpredictable patterns of extreme weather – urban areas are experiencing flooding and drought in the same season - we have come to realise that this is an emergency that demands radical action. Firstly, we must act around on one of the world’s most precious natural resources – water. With the increased consumption of water for industrial processes as well as human consumption, the world’s hydrological cycles have suffered. The urban water cycles have been disrupted, resulting in extreme floods and droughts.

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Our cities, homes and urban environments must adapt to the shift in the global climate and changes in the way we live. Currently our cities and denser urban environments suffer from a lack of ground infiltration to allow more controlled surface water runoff and reduce loading on ageing drainage/ sewer infrastructure. But by mimicking more natural ground infiltration with sustainable drainage systems (SuDS), designed into urban fabric infrastructure and landscapes, even those within more sealed and normally less porous hardscapes (streets, roads, public and civic spaces), we can reduce and slow down surface water runoff, mimicking the natural water cycle to improve water quality and enhance the amenity and biodiversity function and benefit of the built and natural environment around us. These concepts aren’t new but by bringing the principles into our architectural and urban infrastructure as a key form of expression we may define a new visual and sustainable language for our urban settings, ‘Porous Urban Landscapes’.

How often does development address this need and how often do we end up with hard sealed urban landscapes that only serve to enhance flood risk and do not capture water for any form of purification or re-use; missing the opportunity for sustainable water management and its associated infrastructure to support climate and nature positive developments. By implementing urban and civic strategies, replacing hard and impermeable ground cover surfaces with alternative, more permeable and sustainable surfaces, e.g. green infrastructure interventions including above ground soft, green and grey-green solutions like swales, filter strips, permeable paving, that increase shallow and deep runoff infiltration levels, which may in turn filter the harmful sediments from the city and replenish the aquifers with purified freshwater. A green and porous ground plane can also emerge, as a natural by-product, with potential for economic gain through the wide range of functions and benefits afforded to people and wildlife, including space for recreation, restoration and urban habitat, recognising the value of natural assets in an urban context. Tools such as the Building with Nature Standards offer industry a framework of holistic design principles to better understand how ‘soft’ green elements can be integral to the functionality of places, rather than acting merely as adornments to development. In short, we are asking nature to work harder and smarter; to design places that are resilient to change, as we learn to design in an age characterised by uncertainty.

By opting for a reciprocal design approach, we can target the urban realm through three scales of intervention: infrastructure, architecture and landscape. As part of Heta’s design agenda, we are looking at an atlas of elements setting out scalable public realm interventions that facilitates a more sustainable water circulation strategy enhancing the urban fabric of our cities. With the ultimate aim to create more inclusive, resilient and user-friendly urban ecosystems. If we build these principles into future design codes and planning guidance this could ensure private and public sector developments all contribute to this ‘Porous-City’ approach, ultimately shifting the perception of our ground plane, as a more permeable layer to support ecology and allow biodiversity retention & enhancement to increase and flourish, interconnecting ecosystems above and below ground.

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Written by HETA Architects, Amanda Dolga & Jon Fielding
in collaboration with Dr. Gemma Jerome, Building with Nature.

Heta are exploring some of these principles across a number of recent projects; for our elevated urban park in Project Mideo, a new urban district for downtown Seoul, South Korea and the recent award-winning concept for ‘The Future of Co-Living’ a restorative and healing environment for living in harmony with our earth, in collaboration with Dr Gemma Jerome FLI, an ecology, Biodiversity and green infrastructure expert from Building with Nature.