海角视频

It鈥檚 not every day we get to overhear conversations about water, but we recently listened in on a conversation between Carys Thomas and David Palmer from our water team.

鈥淪o what do you think of sponge cities, David?鈥�聽 鈥淚 think they鈥檙e a great concept, Carys.聽 You?鈥澛� 鈥�I love it.聽 The idea of making space for water and creating habitat and enhancing public realm is great. We should adopt for all our new masterplan projects.鈥�聽 鈥淲ell, we do to a large extent, Carys, but it can be a tougher concept to adopt and implement within a well-established and dense urban environment, such as London.鈥澛� 鈥�But, there鈥檚 always something we can do, isn鈥檛 there?鈥�聽 鈥淵es, there always is.聽 Let鈥檚 take a look at this in a bit more detail.鈥� 鈥�Where shall we start, David?鈥�聽 鈥淓rm, let鈥檚 give the beginning a try and see where we get to鈥︹��

In simple terms, a sponge city is a concept that aims to absorb, store, re-use and slowly release rainwater through the adoption of nature-based solutions. The benefits of such an approach include reduced flood risk on and off site, reductions in potable demand, habitat creation, improved air quality, visual amenity, recreation and education.

The reality is that climate change is with us and it is paramount that the resilience of our urban areas is enhanced to ensure a safe and sustainable future. The frequency and intensity of rainfall events are changing and the volume of surface water flow, the magnitude of flood events and the pressure on existing drainage infrastructure is increasing.

The concept of a 鈥渟ponge city鈥� was first identified in China in the early 2000s, as a recognition that traditional 鈥済rey鈥� infrastructure water management systems were not only no longer coping, but were actually exacerbating the impacts of climate change.聽 It was the catastrophic Beijing flood of 2012 that provided the catalyst for research to become national policy.聽 China plans to have 80% of their urban centres harvesting 70% of the rainfall.聽 A truly impressive target.

Like many of the best things in life, the essence of a sponge city is quite straightforward.  The intent is simply to ensure that an urban development is informed, as far as practicable, by the natural framework.  That is, that as much of Mother Nature鈥檚 great work is respected and included within the work of the engineers, architects and planners, as possible.  Sounds simple, doesn鈥檛 it?  And neither is the concept one that is necessarily investment-heavy. 

So, if it鈥檚 not technically complex or financially onerous, what鈥檚 the issue?

The primary challenge is that a sponge city is very space hungry, and space is the commodity that is most at a premium in our long-established urban centres.聽 Once a space is occupied, it can be difficult to find space for greenery, big or small.聽 As we look to transition our urban centres to sponge cities we look greedily, in part, to our highways and pedestrian areas.聽 But these areas are already creaking and under pressure to absorb greater populations, cycle lanes, bus-only lanes and pedestrian only routes.

Even in such constrained areas, there are opportunities for swales within our public realm, rain gardens in traffic islands and roundabouts and permeable paving within our roads, cycle paths and car parks. 

Our towns and cities are blessed with numerous green spaces, which can lend a huge hand when it comes to creating a sponge city.  Catchments ponds, storage areas and swales will reduce run-off, increase infiltration to ground and provide habitat and visual amenity, as well as sources for education, at the same time. It鈥檚 also important that we don鈥檛 just look down.  In 2007 Antony Gormley鈥檚 life-sized statues taught Londoners to look up and our rooftops provide huge opportunities.  Our cities include thousands of square miles of rooftops, which, by and large, provide little value except from keeping the rain from our heads. 

There exists a huge opportunity to turn these areas into multi-use, green, brown, blue roofs, providing benefits in terms of reduced run-off, habitat creation, building insulation, public realm and welfare. 

All of these measures will help make a city 鈥榮pongier鈥� and ease the pressure on our creaking sewer networks and watercourses.  The opportunities abound and it is clear that our success will be driven by the adoption of the full suite of measures, from the micro to the macro scale.

There is no shortage of precedent for this approach, with cities, such as Wuhan and Shenzhen in China, having taken a lead on large-scale sponge city projects.聽 In Europe, Copenhagen and Rotterdam have both taken a lead on nature-based solutions, as have cities in Australia and North America.聽 In London, the Olympic Park leaned heavily on mother nature as many kilometres of hard river edges were restored and wetlands and swales and wet woodlands were created. Similarly, at Mayfield in Manchester, parks are being transformed into sponge parks using swales, raingardens, permeable paving and bio-retention trees.聽

So, what do we need? 

We need buy-in.  From architects, planners, engineers, local authorities and central government to help regulate and ensure the buy-in results in delivery.  We need to adopt the processes defined in guidance such as the London Plan, and government and local government need to ensure that the guidance is extended to include not just the major developments, but all new builds.  If we鈥檙e going to crack this, it鈥檚 important that we have a bottom-up and top-down approach.

鈥淪o what do you think, Carys?鈥�  鈥�Well, I think it all sounds very exciting and doable to me.鈥� 鈥淕reat, shall we get cracking then?鈥� 鈥�Good idea.鈥�&苍产蝉辫;

To find out more about sponge cities and usage, please contact David Palmer or Carys Thomas.