London - NbS for a leading sustainable city

There are a number of potential impacts of NbS that could address the challenges identified for London, which were assessed by the different projects through modelling.

1. Thermal stress

Modelling in BRIDGE has shown that vegetation can be important in adding to shadows at ground level, particularly in summer (Lindberg and Grimmond, 2011). This is important as this is when urban heat waves are more prevalent and heat stress is likely to occur. The mean reduction in mean radiant temperature along a north-south transect across London when vegetation is included is 3.1 °C (min. 1.4 (7S) max 7.5 (9S)) during the summer and 3.2 °C (min. 1.2 (7S) max 3.5 (9S)) during autumn.

1. Flood risk

In BRIDGE, the impact of land use change on the water balance was modelled by changing houses and streets from baseline to green areas with deciduous trees by +/- 2 %, +/- 5 %. For runoff, this showed a decrease to 0.98 and 0.93 (relative change to base) for a 2 % and 5 % increase in deciduous trees respectively (D8.2).

RAMSES is going to apply its flood model to London to identify the flood hazard, exposure and vulnerability, especially for transport. Based on work in Newcastle it is expected that big events cannot be handled by GI alone, but that it can have benefits if placed strategically. RAMSES are working to understand flow paths and to identify the best places for its location. This ties in with a GLA stakeholder in BRIDGE who said that they were supportive of tree planting, but, for managing floods, trees are not helpful. For lower rainfall events, GI can provide benefits especially if it is at or near the source of flow. It is also intended in RAMSES to use modelling to test how different green adaptation options, including blue and green roofs, permeable pavements and urban green space, could affect water flows (D3.3).

TURAS has carried out lab experiments using rainfall simulators into the effectiveness of different types of green roofs with carious substrates under simulated rainfall conditions.

1. Air quality

BRIDGE applied the UFORE model to three scenarios within the CAZ and with two model assumptions: a) 50 % re-suspension of particles b) zero re-suspension. This showed the importance of trees in PM10 removal, with conifers being particularly important due to their greater effectiveness (Tallis et al., 2011), stemming from the presence of their needles all the year round (Table 1). Modelling using two different methods for calculating PM10 removal showed that there could be a 19 % reduction in PM10 removal by 2050 due to a decrease in PM10 exposure (Tallis et al., 2011). If the GLA plan (GLA, 2010) to increase the canopy cover from 20 % to 30 % of the land area by 2050 is realised and the proportion of the different types of tree cover remain the same, then PM10 capture could increase by 18 %.

Table 1: Modelled PM10 removal by street canopy trees (from BRIDGE D3.4).

1. Increasing GI

BRIDGE modelled the potential for green roof expansion based on the slope of the roof (<20 % slope) and the area of roof with that slope (>25 m). It showed that about 15 % of the CAZ area potentially be retrofitted with green roofs (D3.4).

There are a large number of NbS initiatives and actions in London, as they are seen as playing an important role in making London a green capital and in achieving its sustainability goals through addressing multiple objectives. These include mitigating surface water flooding, improving air quality, urban cooling, walking and cycling opportunities, aesthetic improvements and enhancing biodiversity and ecological resilience (Cross River Partnership, 2016). The examples above demonstrate how NbS can not only enhance biodiversity and sustainability, but also contribute to climate mitigation through carbon storage, as well as reducing heat stress and flood risks. They also include exemplars of how these multiple benefits can be achieved, when restoring brownfield sites or constructing green roofs.

The planning process is a key element in the implementation of GI and NbS. For example, the London Plan and local authorities have GI on their agenda, as London has a green roof policy. Also, there has been an important report recently on incorporating nature into housing developments as a way of meeting some of the biodiversity targets in the London Plan (London Assembly, 2017). It includes a number of important NbS-related recommendations, including amendment of the Plan to include ‘net gain’ of nature, and GI is seen as an important mechanism for its delivery.

Data on rainfall simulation of the effectiveness of green roofs with different substrates was passed to the GLA as they were building a GI database and assessing the performance of SUDS. Several projects e.g. with Transport for London, Museum of London and Derbyshire PP linked back to TURAS e.g. Drain London (Connop, pers. comm). Also there was interest from Bowder Engineering, a company fitting green roofs, who wanted to use rainfall simulator to explore the use of different substrates as they wanted to move towards more biodiverse roofs. The revised planning consent for Barking Riverside is almost entirely based on findings from TURAS (J. Sinclair, pers. comm).

TURAS has prepared GI guidelines for local authorities, which are being used by city planners and designers to promote better urban resilience (WP2). TURAS findings are being disseminated through PhD and postdoctoral researchers, and this also helps to expand connections to policy-makers and planners in the case study area and in London as a whole. The TURAS document on ecomimicry (Connop and Nash, 2016) is being sent to local authorities and is part of the information that goes out to developers/landscape architects to show what they can do.

In the River Quaggy, local people were involved throughout the decision-making and implementation process, including providing the land in their gardens for the setback measures (NWRM, no date).

Public-private working occurred in Barking Riverside, where GLA worked with the developer Bellway to ensure the incorporation of GI. It is now seen as an exemplar and has been described as ‘the most exciting project in the whole of London.’ Also in Barking Riverside, where a new community is being created, a Community of Interest Company (CIC) has been established to eventually takeover entirely the management of the public space from the GLA and developer. TURAS (Stuart Connop) is involved in the CIC and providing advice on GI and is helping with the transitioning. TURAS have similarly been involved in other projects round London, including one in Hammersmith (primarily on climate change adaptation) where they talked to residents before designing GI. In Poplar-HARCA, there was an idea to create a Green Mile along the A12  road and TURAS was involved in bringing their GI expertise into the regeneration of the estate, identifying opportunities for GI enhancement and showing how to embed biodiversity, as well as identifying a series of projects to increase its attractiveness and air quality. The document they produced was given to the landscape architects and has become part of a bigger TfL (Transport for London) plan for the A12 (Connop, pers. comm.). TURAS are also working with the London Wildlife Trust who are building a community garden, so that if there is a community event TURAS has a board to explain what rain gardens, SUDS etc., are so that the local residents understand what is there and why.

There is an opportunity to develop and market GI skills as shown by the TURAS experience. Hammersmith Council approached TURAS (University of East London) for training in green skills and SUDS management, as they perceived an overall lack of expertise in GI and thought that they were some of the people who can do it. Tower Hamlets Council also approached them as they wanted SUDS guidance, wanted to learn from Barking Riverside and recognised that they were the only people who could produce tailored guidance for them. TURAS not only worked with them to develop this guidance on GI with biodiversity at its core, but also, as they wanted to demonstrate it could be done, they sourced Pocket Park funding for the SUDS. They won a Landscape Institute award for the design. In addition, Dermott Foley Landscape Architects have been successful in international bids for new NbS and co-creation processes in the last few years drawing upon their experiences as contributors in TURAS (WP2).

Success can revolve around a number of factors including the integration of GI into the planning process, the (early) and full engagement of local communities, the championing of NbS by individuals or organisations. Barriers can be related to personnel and there are also issues around the cost-effectiveness of NbS.

The success of NbS in Barking Riverside owed much to the recognition of the ecosystem value of green space so planning consent for the site set out a number of conditions to ensure sustainability, including:

• the development of sustainable public transport infrastructure;

• the conservation of the site’s valuable biodiversity;

• the retention of 40 % of the site as green space;

• the development of a comprehensive sustainable urban drainage system (SUDS).

The master plan also included the use of green roofs on 40 % of the properties, combined with swales, rain gardens, balancing ponds and the pre-existing creek network. This fits with the BRIDGE suggestion that GI is integrated too late in the planning process, which results in sub-optimal solutions like smaller tree species and irrigation-dependent trees that are decorative but cannot provide environmental services (Task 8.1).

In the GLA, NbS are facilitated by the planning framework which supports and encourages their implementation and there are now a number of very good examples. Also the planning framework is less prescriptive than in other (European) cities. London is possibly a special case, not just because of its size, but also because land values are very high and often high specification developments are carried out in which NbS costs are a small part of the overall development costs. In addition, developers are increasingly concerned about their image and resident pressure, and green approaches help in addressing these (all Peter Massini, pers. comm.).

In the River Quaggy, engagement with the public from the start was seen as critical to the success of the NWRM, as well the residents’ desire and a political will for a more natural option than traditional defences (NWRM, no date). Local residents groups were formed and were involved in various local issues, such as the design of the defences and dealing with Japanese knotweed. Another contribution to its success was the involvement of a multidisciplinary team of engineers, landscape architects, and ecologists in the design to ensure that opportunities for major visual, social and ecological enhancements were optimised while managing the flood risk.

Success can also revolve round an individual, thus changing personnel can be negative if a GI champion is lost, which can lead to many green elements in a new development being left behind for various reasons. For example, Stuart Connop (TURAS) has been important in staying involved with the Barking Riverside development; this is welcomed by the GLA and Barking and Dagenham Council.

A barrier to the implementation of NbS can be a lack of knowledge about cost-effectiveness. For example, a barrier to increasing green canopy cover is a lack of cost/benefit analysis of the various potential multiple monetary benefits e.g. estimating the benefits with respect to health, as well as climate change through a reduction in air conditioning and in flood prevention (BRIDGE 2009). BRIDGE Task 8.1: ‘We are still looking for ways to monetarise the benefits of green, how can we charge back the benefit of greening? Maintenance cost of green often blocks the creation of new areas; but it saves having to pay for sewage, air conditioning etc.’ (Grimmond, 2010).

In the GLA’s assessment of green walls and roofs, a number of barriers to implementation were identified: lack of common standards, fire hazard, maintenance, cost, structural issues, leakage and damage to waterproofing, lack of expertise and lack of policy (GLA, 2008).

The challenges in London are important drivers, especially in the context of sustainability, while the planning process certainly facilitates the implementation of GI and NbS. For example, local authorities have GI on their agenda, as London has a green roof policy and, as stated earlier, in Barking Riverside it was a part of the planning consent: developers had to ensure that there was no greater release of water and biodiversity conservation occurred. Hence, the SUDS strategy is another driver, which can also lead to the release of money e.g. in this case from Thames Water. Also, TURAS established a knowledge transfer partnership between Barking Riverside Ltd, the London Borough of Barking and Dagenham, Livingroofs.org, the University of East London and the Institute for Sustainability to investigate how GI design can increase the sustainability and resilience of the development (Connop and Nash, 2014).

The London Borough of Barking and Dagenham (LBBD) joined TURAS for a variety of reasons including learning from other cities undergoing the same rapid changes and from other project partners, as finding different, smarter ways of working at a time of budget constraints. Furthermore, it was undertaking a massive regeneration programme and needed to ensure the widest possible public involvement with its diverse communities. In the case of Barking Riverside, it wanted to find innovative ways of creating a large new community without losing the existing communities and doing so in a way that involved the communities both now and in the future. In TURAS the LBBD also worked with the Environment Agency for Brussels; BIC Lazio and the Municipality of Rome. In addition it co-produced some community material with Dublin City Council. Its involvement in TURAS enabled it to expand and accelerate its cross-disciplinary working, both within and beyond the municipality. This was especially helpful in the context of GI and community engagement.

In the River Quaggy, the original plan was to further raise the existing walls, however, this would have resulted in the loss of a large number of well-established trees (NWRM, no date). There was large local resistance to this approach and a strong political and local desire for a (more natural) flood storage solution rather than concrete channels.

The London Plan has a plan-monitor-manage process to track the overall direction of its associated policies, with a monitoring report based on 24 key performance indicators produced annually (GLA, 2016). These indicators include: minimising the loss of open space; increasing urban greening (increasing the total area of green roofs in the CAZ); reducing carbon emissions; protecting biodiversity habitat (no net loss of designated Sites of Importance for Nature Conservation) and improving London’s Blue Ribbon Network (restoring 15 km of rivers and streams in 2009 - 2015 and an additional 10 km by 2020). The report on encouraging nature in new housing development suggests that the Mayor should request that all developments share ecological data with Greenspace Information for Greater London after a development is completed (London Assembly, 2017).

In the River Quaggy, a number of parameters were monitored during different stages of the scheme (NWRM, no date). Prior to construction, 11 baseline surveys were carried out including surveys of riverine flora, trees, bats, fish, invertebrates, birds and mammals to inform designs in progress and enable the process of environmental impact assessment. Water quality and sediment sampling was also undertaken and socioeconomic surveys carried out after the completion of the scheme to monitor visitor numbers to the park storage.

In the TURAS London case studies there was a lot of monitoring, as it is one of the solutions to understanding how to plan and deliver GI. For example, in the Thames Gateway, TURAS used the Natural England monitoring system on habitats on brownfield sites to identify which habitats were present or absent and then to see how they could be incorporated into green roofs and landscape design (Connop pers. comm.). They found that ephemeral wetland sites were missing so they tried experimenting on green roofs at Barking Riverside and the University of East London, by raising one side of the roof 25 mm or 50 mm and creating wetter areas, with raising one side by 50 mm leading to some permanent areas of water. Monitoring was also an important part of the development of the brownfield site habitats in Barking Riverside (Connop et al., 2014).

For the GLA, involvement in TURAS provided an opportunity to think about how to ensure landscape design for urban regeneration can be done using more ecological/NbS approaches when starting with a blank canvas, with Barking Riverside as a good example. Outputs from TURAS have informed the Housing and Land Team and they would like to encourage other boroughs to recognise the important work that has be done at Barking Riverside and how work e.g. on green roofs could be transferred. There have been discussions with RAMSES (Richard Dawson) to see how the work on NbS for water management could be applied in London. The GLA is, through the Local Governments for Sustainability (ICLEI), linked to other cities, although it is difficult to keep up with all that is going on and to find the time to participate more actively. The GLA is also involved in a Horizon 2020 NbS bid in conjunction with Milan and Hamburg. It is also involved with Groundwork (London) in Fulham in retrofitting climate change adaptation measures to a housing estate.

The report on incorporating nature into housing developments cites TURAS and Barking Riverside as an example of getting GI into a development (London Assembly, 2017) and the London Infrastructure Plan 2050 (Mayor of London, 2015) cites Barking Riverside as an example of major regeneration good practice.

The NWRM project, in which the River Quaggy was a case study, was led by the Office International de l’Eau (OIEau), in consortium with Actéon Environment (France), AMEC Foster Wheeler (United Kingdom), BEF (Baltic States), ENVECO (Sweden), IACO (Cyprus/Greece), IMDEA Water (Spain), REC (Hungary/Central & Eastern Europe), REKK inc. (Hungary), SLU (Sweden) and SRUC (UK) for DG Environment.

Public Health England has a Healthy New Towns project to look at mental health issues and Barking Riverside has been chosen as one of the pilots. A new H2020 Innovation Action, CONNECTING, is built on the findings of TURAS and the University of East London is involved in an academy to train people in GI, bringing examples from London and other cities, as well as the CIC experience.

The benefits of TURAS are a new approach to problem solving; a realisation that working on resilience and sustainability is not doing more with less but achieving the result by doing things differently. TURAS has been invaluable in terms of engaging with organisations across Europe in discussing problems and finding solutions. The mix of public sector authorities, universities and private sector organisations has been critical and the learnings and tools resulting from TURAS (as well as the networks) will be useful for the long term (Harley and Sinclair, no date).

Drawing up the case studies (e.g. Barking Riverside) enabled the LBBD to consolidate the knowledge that it had about how processes really worked. Other TURAS case studies and tools — e.g. the interactive timeline, ‘join the dots,’ community funding as well as the set of tools around urban green infrastructure are also of use. In addition, since the inception of the TURAS programme, LBBD has gone on to found its own energy company in order to bring cheaper and more efficient sources of energy to its residents. While these measures are not directly caused by TURAS, its influence has been material.

TURAS is feeding into the local development framework and fed directly into the environmental impact statement for the revised planning application for Barking Riverside. TURAS is also influencing the development of the Community Interest Company which will manage the infrastructure and running of Barking Riverside as it is built out.