Blue green solutions: a systems approach to sustainable, resilient and cost-efficient urban development

Between 1950 and 2014, the global urban population underwent a five-fold increase, rising from 0.75 billion to 3.9 billion. Increased urbanisation brings with it a host of problems: increased pressure on essential resources such as food and water; increased air pollution due to transportation; loss of biodiversity; and increased risk of ill health (Figure 1). The challenge posed by urbanisation is, however, magnified when coupled with climate change. Climate change is expected to lead to more extreme weather events in the form of severe floods, droughts and heat waves1-6. Such events can spell disaster for a city, especially when it is already dealing with the challenges that increasing urbanisation presents.

Urban planners and local governments are working to address these challenges. Many recognise that bringing Nature Based Solutions into the city is a powerful remedy for alleviating urban pressures and achieving resilience to climate change. Proven benefits of Nature Based Solutions7-12 include reduction of water and air pollution, mitigation of flood risk and heat islands, increased resource efficiency, as well as provision of areas for recreation/amenity and urban agriculture. A key advantage is that being vegetation based, their construction and operation has a low carbon and materials footprint. Other benefits include improved financial and aesthetic property values, job creation, reduced building running costs and lower health and insurance premiums. However, at present we are not getting the best out of Nature Based Solutions (NBS), neither for new developments, nor for retrofits.

NBS are often used in a mono-functional way, e.g. to provide shading or detain stormwater runoff, or simply for their aesthetic value. Moreover, they are usually valued only in terms of their benefits to the developer/principal stakeholder(s). In fact, a key advantage of NBS is that they can provide multiple benefits to multiple stakeholders. Many of these co-benefits only arise when NBS are planned so as to utilise their beneficial interactions (synergies) with the local urban environment. The challenge therefore, both for new developments and for retrofits, is to enable current urban planning practice to realise the synergistic benefits of NBS. The Climate-KIC Innovation project Blue Green Dream (2012-2015), led by Imperial College London, initiated a step-change in how we map and exploit the potential benefits of NBS.

A key focus was the use of NBS to achieve urban sustainability and climate change resilience. What really set the Blue Green Dream project apart from other NBS (especially, green infrastructure) projects were two key innovations: Its holistic, integrated planning methodology, which entails engaging with a wide panel of stakeholders across the whole planning process. The concept of modelling, quantifying and optimising potential synergies between NBS, local water resources, the local built environment and climate, innovations in urban design and architecture, etc., to achieve lower life-cycle costs and enhanced benefits. The Blue Green Dream project was awarded the 2015 Business Green Technology Award for Research and Development Programme of the Year13.

This guide presents the integrated planning methodology developed from the Blue Green Dream Project, referred to hereafter as the Blue Green (BG) Systems approach. We showcase several case studies, each demonstrating a different element of our approach. The case studies show that through applying this holistic, quantitative approach to their planning and design, NBS can be highly costeffective. Not only do they increase the value of developments, but they deliver substantial savings in operational costs. This guide contributes to Climate-KIC’s ‘Urban Transitions’ theme, showcasing its novel approach to creating low carbon and resilient cities.

source :
https://www.climate-kic.org/wp-content/uploads/2018/03/BGDGuide.pdf