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range of multi-value extra benefits, such as for people first by identifying measures that reductions in energy use, the heat island can best support their needs. Considering effect and noise pollution, and increases micro-climates and the correct planting in community cohesion, recreational can create positive effects. Ecological opportunity and habitat. and pedestrian connections will already exist, but considering how they can be In the UK, these approaches have also improved will enhance the local amenity started to be used on a small scale. For and biodiversity. example, at Halewood Primary School in Merseyside, retrofit SuDS have been built Planning ahead is important. Any space to reduce the risk of flooding to the school that has an ambiguous function will most playing field. The Green Infrastructure likely fall into disrepair. Retrofitted SWMM North West Valuation Toolkit was used to should have a clear function and where assess a total of 12 different benefits. This possible measures should have more than resulted in a net present value of £80 000 one use. For example, an auditorium in a over a 50 year period, and although there is school playground in Sweden (Figure 7) some sensitivity in the monetised benefits, also functions as a surface water storage they provide a helpful indication to the likely area during heavy rainfall. Good places are scale of the benefits that will be created never finished, they evolve, so places should from such work. be designed to have the ability to adapt to changes in the future. The importance of good urban design Figure 5 Rain garden built in Ashby Grove, Where possible, retrofit SWMM should London to collect roof water and infiltrate into be integrated into an urban area in an the ground appropriate way. Understanding the views of the local community is extremely When using a wide range of SWMM, important. Their views can influence what especially those that are above ground, a SWMM will look like once constructed. far wider range of benefits (than pollution Engaging with local communities can and flood risk) become possible, which take time. Experience shows that the are often not seen when traditional below early involvement of local communities, ground measures (such as pipes) are used. understanding what is important to them These benefits can include: and explaining problems some time before reducing the financial and carbon costs delivering solutions can lead to successful of wastewater treatment and pumping retrofitting of a range of measures. increasing property values through an Identifying a range of key issues that are enhanced urban area important to the local communities helps to capture their attention, giving them a greater replenishing of water resources stronger reason to be involved. and reducing water use reducing air and noise pollution To ensure that measures are appropriate enhancing biodiversity by creating new for an area (beyond the main drainage or improved habitats considerations), the context in which better health through increasing levels retrofitting occurs should be understood. of exercise and outdoor activity from This includes understanding each place’s Figure 6 The Dings, Bristol where permeable improved urban spaces characteristics, building typology, layout and pavement was retrofitted during the creation orientation, ecology, and the views of the of the ‘Homezones’ area (courtesy of Sustrain) mitigating the urban heat island effect local community. The Spaceshaper Toolkit creating greater awareness and by CABE (2007) can help to measure the How to retrofit understanding of water by involving quality of the existing space. In the UK, a wide range of SWMM are society. starting to be considered and used to It is now possible to start valuing these To ensure that any retrofit measures are manage surface water. To date there have extra benefits, which is important given successfully integrated, an understanding been several exemplar projects such as the current emphasis being placed on of the scale of the retrofit also will be Ashby Grove (Figure 5) and The Dings demonstrating the benefit and cost of required. Depending on whether the Bristol (Figure 6). Many of these have solutions to manage surface water. Work measures are to be incorporated on a come about due to local champions making overseas, particularly in Australia and single plot, across a street, throughout it happen and proving that retrofitting the USA, has shown that these benefits a neighbourhood or within the whole non-traditional SWMM can be achieved can be quantified on large infrastructure catchment will influence the choice of in the UK. However, it is also clear that projects. For example, in Philadelphia, USA, measures used and their design. Different examples from a business as usual approach a combined surface water management places suit different measures and different are emerging. Organisations, such as approach of a tunnel and above ground designs so it is important to consider when Ofwat recognise that using a wider range (green infrastructure) features will create an to introduce hard and soft features and of measures will be important and have estimated $3bn of benefits over a 40 year how to mix them. asked water and sewerage companies to lifetime. The green values calculator from consider using them in designs during the the Center for Neighborhood Technology People need to be able to move around current asset management period (AMP) (CNT, 2010) was used, which includes a safely and freely. So the design should cater (2010–2015). 3


evolutionwinter2012
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