Urban design with Blue-Green infrastructure plays a key role in addressing climate related water challenges such as water pollution, water scarcity, floods, land subsidence, stormwater management, ecosystem services and public health. Nanco Dolman (Royal HaskoningDHV) discusses this in greater detail.

Integrated water management

Integration of water management in the different phases of design and development is incredibly important in urban retrofit projects and new development.

Approaches such as water-sensitive urban design (WSUD) provide useful tools for strengthening the integration of water in spatial planning and urban design processes, requiring any spatial intervention or new development to be evaluated on opportunities for sustainability and innovation.

Nature-based solutions (NBS), sustainable drainage systems (SuDS) and blue-green infrastructure (BGI, e.g. urban wetlands, green roofs, swales, rain gardens, detention basins and ponds) are widely employed. These approaches enrich society through the provision of multiple co-benefits, including access to public greenspace, recreational opportunities, aesthetic enhancements, and improved management of environmental processes such as flooding, drought, urban heat and air pollution.

Just as infrastructure and the choice of development site are key factors in planning considerations, water management has a legitimate claim to be considered in this process. It is not just about open water and riverbanks: the choice of rainwater and wastewater systems also determine the required water storage facilities. Water is a connecting challenge in making cities resilient. Water then becomes a focal way of looking at cities and making them climate- and future-proof.

This makes it possible to move towards a balanced approach to treat precipitation close to where it lands through measures that deliver multiple benefits for water management alongside environmental and amenity benefits.

New and retrofit SuDS are being developed in appropriate places and integrated with programmes to deliver better and larger sewer systems. More projects are taking an urban design approach by building adaptively with water in mind and by investing in BGI. By strengthening BGI and giving water more space in both the public and private domain, the water city of the future has the potential to grow into a Blue-Green City.

Living with and making space for water

Solving the urban water assignment, or required storage capacity, is centred on ‘living with and making space for water’. This is both an engineering and design challenge. We must consider optional alternatives during the design process by linking the water assignment (e.g. required water storage) to BGI metrics (e.g. system and site scale measures). Figure 1 distinguishes the following four quadrants:

1. Urban typologies – land use analysis in layers
2. Water systems approach – cities as water catchments
3. The urban water assignment
4. Blue-green infrastructure – cities as ecosystem services providers

Figure 1. Linking the urban water assignment to Blue-Green infrastructure metrics

Urban typologies – the Dutch layers approach

In 1998, a stratified model that distinguished spatial planning tasks based on the differing spatial dynamics of substratum, networks and occupation patterns – i.e. three layers – was introduced in the national debate on spatial planning in the Netherlands. Although using layered models was not a new thing, this model hit a nerve in spatial planning practice, initially on a national level, but later also on provincial and municipal levels. Since 1998, this “layers model” has developed into an approach to spatial planning and design: the Dutch layers approach.

Water systems approach – cities as water catchments

One of the layers to spatial planning and design is the water system, both on the surface and sub-surface. Cities are part of, and have developed in, water catchments. Understanding both the urban and natural water system is vital when proposing and evaluating spatial interventions or new development. After the mid-19^th century, towns and cities expanded to accommodate growth in industrial activity and population. Many waterways lost their infrastructure function and were filled in. During the 20^th century the urbanisation pattern became linked to the new motorway network and water stopped contributing an organising role in urban development, whilst hydraulic engineering expertise made it possible to protect the land from flooding.

The urban water assignment

The water system analysis can be captured in a water balance or hydrological model. The starting point for the design of any urban water system is an overview of the functions the water system must fulfil, now and in a sustainable future. These functions and functionalities are the basis for the design standards that are to be applied. Such an overview of functions (or ecosystem services) should be composed for all five types of urban water (surface water, groundwater, rainwater, wastewater and drinking water), as well as for the urban soil and subsurface.

Storage and discharge are exchangeable. Stormwater runoff that we cannot discharge into the drainage system needs to be stored temporarily in the urban environment. We will have to discharge any runoff we do not have capacity to store. The required storage capacity (or water assignment) does not only depend on runoff intensity, but also on discharge capacity. As designers we want to understand the relationship between the required storage capacity and discharge capacity.

Runoff intensity and volume can also be reduced. Runoff intensity depends on the design and construction of the buildings, streets, gardens and other urban infrastructure. Normally storm water will drain quickly from roofs and streets to canals and ponds via the storm sewers; the delay will be no more than 5-15 minutes and runoff losses could be 10% or less. But if we could divert the storm water to an infiltration facility via urban groundwater – in many cases a subsurface drainage system – the delay would be hundreds or even a thousand times larger.

Blue-Green infrastructure – cities providing ecosystem services

The design solutions to solve the water assignment are elaborated in city planning and in urban vision (statement) projects as well as demonstration (pilot) projects. Some practical measures and optional alternatives, both at system and site scales, include: (re) use of water, surface drainage (delay), retention (streets, parks), infiltration (swales), green infrastructure, storage of surface water, and adaptive and flood-proof building.

Plenty of BGI elements exist to reduce runoff and create numerous alternative options for solving the storage design problem. These alternatives must be addressed during the design process by at least considering separately a fast surface and piped runoff component and a slow runoff component through the soil/subsurface drainage system. Incorporating these best practice guidelines or BGI elements in a manual would be the next step forward.

Justification

The contents of this blog have been adapted based on part of the chapter [2] on ‘Integration of water management and urban design for climate resilient cities’ in the forthcoming Palgrave Macmillan book on ‘Climate Resilient Urban Areas – Governance, design and development in coastal delta cities’.

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When we think about public infrastructure, such as roads, parks, or even sewers, we often think of large, connected systems that are easy to spot and hard to ignore. But what about the more hidden types of infrastructure that are decentralised and small but collectively serve a big purpose? Blue-green infrastructure (BGI), such as green roofs, bioswales, rain barrels and rain gardens, are exactly this (Figures 1 and 2). While some BGI approaches, such as rain barrels (water butts), are on an individual’s private property, other approaches, such as bioswales and rain gardens, are in the public right-of-way. How will BGI, an important piece of the public infrastructure puzzle, be maintained as city budgets continue to come under pressure?

Figure 1. Green roofs in Portland’s South Waterfront District

Introducing the study

To explore this question, our study estimated people’s willingness-to-pay (in dollars) and willingness-to-volunteer (in hours) to maintain BGI. We surveyed residents in two major U.S. cities (Chicago, Illinois and Portland, Oregon) that are leaders in adopting innovative approaches for stormwater management. While using surveys to estimate willingness-to-pay for public goods is frequently done, our study used a novel approach that allowed us to also estimate the number of hours a resident would be willing to volunteer in their neighbourhood to maintain BGI. This is particularly important for small, decentralised BGI systems that are costly for municipal workers to access and maintain, but are hyper-local and easily accessed by nearby residents in their own neighbourhoods. We found that residents are, in fact, willing to donate a significant amount of time to maintain BGI.

Multiple benefits

Incorporating BGI into stormwater systems provides numerous benefits that are often bundled together. We estimated people’s willingness-to-pay and willingness-to-volunteer for specific benefits from BGI (not just the bundled outcome) such as improvements in water quality, improvements in aquatic habitat quality, and reductions in flood frequency. While it’s not surprising that we found residents strongly value reductions in the frequency of flooding, we also found that people place non-trivial values (both in dollars and in volunteer hours) on improvements in water quality and aquatic habitat.

Figure 2. Bioswale adjacent to a house listed for sale

For example, we estimated the benefits of a hypothetical program that would improve aquatic habitat from its current level (fair) to the highest possible level (excellent), water quality from its current level (boatable) to the highest possible level (swimmable), and would reduce flooding by 50%. The annual household willingness-to-pay for this program was $323 in Chicago and $279 in Portland with aggregate willingness-to-pay (based on the number of households in each city) of $4,015 million in Chicago and $856 million in Portland. The annual willingness-to-volunteer to participate in a program that would achieve these goals was 29 hours per household in Chicago and 77 hours per household in Portland.

Figure 3. Outreach efforts: Portland’s Green Streets medallion and green infrastructure sign

Motivation to maintain BGI

What motivates people to volunteer to support BGI? We found that people derive significant enjoyment from volunteering in their neighbourhoods to support BGI. Other possible reasons why residents volunteer to maintain BGI include the link between BGI and property values (Figure 2) and extensive efforts by government agencies to educate residents about the relationship between BGI, stormwater runoff, water quality, and reduced sewer overflows (Figure 3).

Portland’s Green Streets Steward Program has around 200 participants with some stewards reporting that they maintain their green street on a weekly basis while others report maintenance occurring on a monthly or quarterly basis. Understanding what motivates residents to volunteer to maintain BGI remains an important area for future research, but “[o]ur results are cautiously encouraging for urban stormwater managers hoping to muster an army of volunteers to help maintain decentralised GI” (Ando et al. 2020,13).

Authors

Noelwah R. Netusil, Reed College (Portland, Oregon) and Bryan Parthum, University of Illinois (Urbana, Illinois).

For more information

The paper, “Willingness-to-volunteer and stability of preferences between cities: Estimating the benefits of stormwater management,” is published in the Journal of Environmental Economics and Management. [https://doi.org/10.1016/j.jeem.2019.102274]

A press release about the paper is available at: https://aces.illinois.edu/news/stormwater-management-and-green-infrastructure-provide-benefits-urban-residents-are-willing

Portland’s Green Streets Steward Program: https://www.portlandoregon.gov/bes/52501

Bioswale in the public right-of-way

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“We live in an isolated age.” An age where people are separated from nature and cities are disconnected from green fields. Today, Chinese cities are facing rapid urbanisation, leading to fast growing urban populations. For example, the population in Shanghai currently exceeds 24 million, in Guangzhou there are over 15 million, Beijing over 12 million, and Shenzhen over 10 million people. Chinese cities are also experiencing declines in urban environmental quality. Lei Li and Faith Chan (University of Nottingham Ningbo China) explore whether the Sponge City Program (SCP) can help reduce these risks through effective water cycle management.

Sponge City Program

The Sponge City Program (SCP) is a new concept for Chinese cities, aiming to manage urban stormwater by utilising Blue-Green Infrastructure (BGI). This will bring a more natural water cycle back into cities through accumulation, filtration, purification, storage and reuse of rainwater, as well as providing co-benefits to the environment and society. The SCP was proposed in December 2013 by the National Government. Several institutions, including the Ministries of Finance, Water Resources, and Housing and Rural-Urban Development, launched the pilot program. This comprised 16 pilot cities in the first batch and 14 pilot cities in the second batch.

The National Government issued SCP guidelines in October 2015, dictating that 20% of urban areas should include ‘sponge’ features (e.g. rain gardens, swales, wetlands, ponds and permeable paving). This increases to 70% by 2020 and 80% by 2030. Achieving this goal will mean retrofitting existing urban areas and implementing SCP measures in new towns and developments.

Ningbo

Ningbo was selected for the SCP in 2015. So far, efforts have improved the water quality in urban catchments and rivers. Nutrient levels have reduced and waterlogging has been alleviated, improving the urban living environment. There are some great examples, such as Shuanggudu Park (Figure 1), Eco-corridor in Ningbo New East town (Figure 2), New Ci Town (Figure 3), New Sanjiangkou Park, Xiejia Binjiang Park and Yaojiang Binjiang Park. Urban recreational space has increased significantly, and cities have become ecological and liveable. One of the SCP features in Ningbo is the combination of grey infrastructure and BGI, which effectively treat urban stormwater discharge and runoff.

Figure 1. Shuanggudu Park in Ningbo (source: Zhou, 2019)

Figure 2. Eco-corridor in Ningbo New East town (source: Ningbo Municipal Government, 2018)

Figure 3. The central lake in New Ci Town in Ningbo (source: Xie and Ying, 2017)

SCP in 2020

The SCP is now at a crossroads after almost 5 years since the program initiated. Doubts and uncertainties have been raised and there are queries from the media regarding the effectiveness. Headlines include: ‘Pilots of 30 sponge cities nationwide, 19 cities experienced flooding this year’ (Wang, 2016), ‘The “Sponge City” must address water uncertainty‘ (Beijing Youth Daily, 2016), ‘Sponge City is still waterlogged, related issues remain to be clarified’ (Hu, 2017). Only relying on the SCP and BGI cannot completely solve urban floods in Chinese cities.

Perceptions and functionality

Public perceptions of the function of Sponge Cities often differ to the technical guidance published by the National Government (Ministry of Housing and Urban-Rural Development (MOHURD), 2014). Chan et al. (2018) argued that according to the SCP guidelines, infrastructure can only withstand 1-in-30 year return period stormwater events. SCP measures are not designed for intensive rainstorms (e.g. generated by typhoons) or climatic extremes (high magnitude floods and droughts). They are an important part of the solution to managing flood risk in Chinese cities, but not the only part.

We want to emphasis that the SCP cannot solve all urban flood and water management issues. We encourage stakeholders to be patient and give the SCP time to be completed, and benefits to accrue. SCP projects offer many benefits, and, importantly, are implemented is public places (e.g. urban wetland parks). This increases recreational opportunities and may help improve social wellbeing (e.g. health and happiness) and environmental awareness of future challenges (e.g. climate change, land use change).

“We should bear in mind that profound changes in attitudes, behaviours and policies will be required to create a world in which human beings live in harmony with nature.”

Sam Kahamba Kutesa, UN General Assembly President, during the Dialogue on Harmony with Nature (UN News, 2015).

Understanding of urban ecosystems and planning of future cities require comprehensive thinking and innovative design, and perhaps a little imagination and passion. The SCP provides opportunity to boost up the greenery and nature in Chinese cities, while managing water challenges.

Authors:

Lei Li (Postgraduate Researcher on Nature Based Solutions, Green Infrastructure and Sponge Cities, School of Geographical Sciences, University of Nottingham Ningbo China)

Faith Chan (Associate Professor, School of Geographical Sciences, University of Nottingham Ningbo China)

References

• Beijing Youth Daily (2016). The “Sponge City” must address water uncertainty.
• Chan, F. K. S., et al. (2018). “Sponge City” in China—A breakthrough of planning and flood risk management in the urban context. Land Use Policy, 76, 772–778.
• General Office of the State Council (2015). Guiding Opinions of the General Office of the State Council on Promoting the Construction of the Sponge City. Beijing, People’s Republic of China: General Office of the State Council.
• Ministry of Housing and Urban-Rural Development (MOHURD). (2014). The construction guideline of Sponge City in China. Low impact development of storm water system. Beijing, People’s Republic of China: MOHURD.
• Hu, H.D. (2017). Sponge City is still waterlogged, related issues remain to be clarified. Shanghai Information platform. December 12, Available at: http://www.istis.sh.cn/list/list.aspx?id=10935. (Accessed: 6 March 2020).
• Ningbo Municipal Government (2018). The new appearance of Ningbo New East Town Eco-Corridor Phase II and Yongxin River Park. Available at: http://gtoc.ningbo.gov.cn/art/2018/9/30/art_168_951559.html (Accessed: 6 March 2020).
• Sidner, L. (2017). Sponge City: Solutions for China’s Thirsty and Flooded Cities, NewSecurityBeat, June 21, Available at: https://www.newsecuritybeat.org/2017/07/sponge-city-solutions-chinas-thirsty-flooded-cities/ (Accessed: 6 March 2020).
• Statement at the Interactive Dialogue on Harmony with Nature | General Assembly of the United Nations. Available at: http://www.un.org/pga/270415_statement-interactive-dialogue-on-harmony-with-nature/  (Accessed: 6 March 2020).
• Wang H.R. (2016) A pilot of 30 sponge cities nationwide, 19 cities have experienced flooding this year, China Economic Weekly, (35), 48-50.
• Xie, Y. and Ying, L. (2017). Sponge city, people and water in harmony, Ningbo Ci Town leads in creating a “Sponge” demonstration area Zhejiang News, Available at: https://zj.zjol.com.cn/news/731728.html?ismobilephone=1&t=1529196447898 (Accessed: 6 March 2020).
• Zhou, K.N. (2019). What is the “visible” effect of Ningbo sponge city construction? What can be shared? Zhejiang News, Available at: http://zjnews.zjol.com.cn/zjnews/nbnews/201902/t20190227_9545808.shtml (Accessed: 6 March 2020).

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In early November the Amsterdam International Water Week (AIWW) brought together leaders from government, the private sector and academia to explore a new era of sustainable water management. AIWW is a global movement committed to a future in which a circular and sustainable water environment is achieved. One of the core topic areas this year was ‘Blue-green solutions for urban resilience’, which aligns with the research we are conducting as part of the ‘Blue-Green Futures‘ project. In this blog post, Nanco Dolman and I (Emily O’Donnell) reflect on the key themes.

Resilient Cities Leaders Forum

On 4^th November we participated in the Resilient Cities Leaders Forum on the Water Sensitive Futures table. Nanco hosted the table and I was an expert contributor. We shared experiences of water sensitive urban design and Blue-Green Infrastructure (e.g. swales, rain gardens, green roofs, restored river channels) being used to manage flood risk, enhance the environment and improve quality of life. Best practice approaches in Denmark, Australia, New Zealand and the Netherlands were discussed. We also shared our ongoing research into how socio-political barriers to the implementation of Blue-Green infrastructure have been overcome in four international cities (Newcastle, UK; Ningbo, China; Rotterdam, Netherlands; and Portland, Oregon USA) – see our earlier blog for further insight.

Resilient City Leaders Forum discussions on Table 9, City of Vejle (Denmark): Developing water sensitive futures (photo credit: Guus Schoonewille).

Business as usual is not enough

The conference featured many inspiring speakers passionate about global cooperation to achieve the Sustainable Development Goals (SDGs) and to create sustainable solutions across water, waste, urban development, energy and finance. Henk Ovink, Special Envoy for International Water Affairs, delivered one of the opening keynotes that set the tone for the conference. Water is central to the climate crisis and central to the delivery of the SDGs. Business as usual is not enough, and in fact, business as usual is lethal.

There is no silver bullet to address global water challenges but collaboration with all stakeholder groups is essential, as is the combination of long-term planning and short term action. The solutions to global water challenges are not easy but the will to make the changes needed has to be present, and this is something that is lacking in many countries. What was echoed many times throughout the day was the need for action.

While it is essential to continue scientific research and keep developing innovative solutions to mitigate risk and improve peoples’ quality of life, there has to be action and a commitment to making changes, even if the economic cost is high. As echoed by David Nabarro, Former UN special adviser on the 2030 Agenda for Sustainable Development, we cannot wait for another disaster to happen.

AIWW 2019 was officially opened in a late afternoon ceremony by a video message from Ban Ki-moon, former Secretary-General of the United Nations, and leader of the Global Commission on Adaptation. He reiterated the need for action on climate change.

Day 2 – collaboration to build more resilient communities

Day 2 of the AIWW conference offered a choice of more substantive sessions, including dissemination of research, new developments and sharing practitioner experience. The key message was a need for continued collaboration to build more resilient communities.

To stimulate collaboration and accelerate dialogue between actors, a new gamified tool called STAIN was presented in the “Blue-green solutions with focus on inclusive city master planning” morning session. This digital twin city game enables the design of city resilience strategies as part of early stage multi-stakeholder analyses. It emphasises the role of local knowledge and personal interpretation of Blue-Green solutions, combining these with city data and risk data to improve the quantification of urban resilience. The city of Rotterdam, one of the Blue-Green Futures case study cities, was the first city to use STAIN to develop a Blue-Green vision for the Rotterdam-North neighbourhood.

Benchmarking cities to encourage more Blue-Green infrastructure

An afternoon workshop session was dedicated to benchmarking cities to stimulate the implementation of Blue-Green infrastructure. In the EU Interreg CATCH-project, an online decision support tool (DST) has been developed that can support cities to develop tailor-made, long term adaptation strategies. This DST builds on the ‘Water Sensitive City’ (Wong and Brown, 2008) theory that combines physical infrastructure (e.g. Blue-Green), with social systems (e.g. governance and engagement). The aim is to create cities where the infrastructure and systems enhance the connections that people have with water, and ultimately improve quality of life.

Benchmarking of cities and navigation in planning for climate adaptation” session (photo credit: Anne Fleur Weusthuis).

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Authors: Noelwah R. Netusil and Ben Thomas, Reed College (Portland, Oregon).

Portland, Oregon, USA was identified as an international leader in the Blue-Green Futures questionnaire that explored the perceived benefits, beneficiaries, multifunctionality and challenges of planning and delivering Blue-Green infrastructure (see our earlier blog).

Portland has relied heavily on green infrastructure (GI) projects, such as ecoroofs (also known as green roofs or living roofs) and green streets to reduce stormwater runoff (Figures 1-3). The primary driver for adopting these approaches is to reduce flooding and combined sewer overflows, but other GI benefits include a reduction in urban water pollution and the creation of open space.

Figure 1. Ecoroof on the Academic and Student Recreation Center at Portland State University. Photo credit: Noelwah Netusil.

Figure 2. Solar panels and vegetation on top of the Science Research and Teaching Center at Portland State University. Photo credit: Noelwah Netusil.

Figure 3. Ecoroof on the Academic and Student Recreation Center at Portland State University. Photo credit: Noelwah Netusil.

Ecoroof dimensions and policies

Portland has used a combination of education, incentive-based policies, and regulations to increase the number of ecoroofs. An ecoroof incentive program, which was in place from 2008-2012, provided private developers with a subsidy of up to $5 per square foot and the potential to qualify for a building density bonus (Environmental Services 2019). As of 2019, there were almost 400 ecoroofs in the city of Portland with 152 ecoroofs (almost 1 million square feet) on properties with a commercial use (Table 1). Institutional buildings, which include colleges, universities and hospitals, accounted for almost the same total square footage as government buildings.

While residential buildings with ecoroofs are distributed around the city, ecoroofs on commercial, government and institutional buildings are more concentrated in downtown Portland (Figure 4).

Table 1. Portland Ecoroof Building Use and Square Footage (Source: Portland State University, Portland’s Greenroof information Thinktank (GRiT), and Portland State University’s Home Ecology Research (HERE) Lab).

Figure 4. Ecoroof Location in Portland by Building Use (Source: Portland State University, Portland’s Greenroof information Thinktank (GRiT), and Portland State University’s Home Ecology Research (HERE) Lab).

Central City Plan 2035

In May 2018, the Portland City Council adopted the Central City 2035 Plan that added an ecoroof requirement to Portland’s Zoning Code for new buildings with a net building area of 20,000 square feet or more (Environmental Services 2018; City of Portland 2019). This is viewed as one of the most (if not the most) stringent ecoroof requirement in the US. However, the three buildings that would have been required to install an ecoroof as part of the new requirement received exemptions.

Ecoroof research

Much research exists on the private benefits from ecoroofs such as the reduction in energy costs and increased roof lifespan. As detailed in “Valuing the Benefits of Green Stormwater Infrastructure” (Ando and Netusil 2018), there exists a gap in the literature on valuing the public benefits of ecoroofs such as the benefits from allowing public access, reducing stormwater runoff (and combined sewer overflows), mitigating the urban heat island effect, and increasing the number of pollinators. A research team from Reed College (Noelwah R. Netusil), Portland State University (Sahan Dissanayake), and the University of Illinois at Urbana-Champaign (Amy W. Ando) is in the process of designing a choice experiment to value the public benefits from ecoroofs with a goal of sharing their findings with policymakers and ecoroof designers.

References

Ando, Amy W., and Noelwah R. Netusil. 2018. Valuing the Benefits of Green Stormwater Infrastructure. Vol. 1. Oxford University Press. https://doi.org/10.1093/acrefore/9780199389414.013.605.

City of Portland Environmental Services. 2018. Guidance on CC2035 Ecoroof Requirements and the SWMM.  Available at: https://www.portlandoregon.gov/bes/article/691262

City of Portland Environmental Services. 2019. Portland Ecoroofs.  Available at: https://www.portlandoregon.gov/bes/44422

City of Portland. 2019 Central City Plan, Title 33, Planning and Zoning (§33.510.243 Ecoroofs) (March 1).  Available at: https://www.portlandoregon.gov/bps/article/53363

Portland State University, Portland’s Greenroof information Thinktank (GRiT), and Portland State University’s Home Ecology Research (HERE) Lab. 2019. Portland Ecoroof Map. Available at: https://ecoroofs.research.pdx.edu/#!/

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Behaviour has been shown to be predicted by a combination of implicit (subconscious) and explicit (conscious) attitudes and perceptions. Explicit perceptions can be captured through techniques such as questionnaires, interviews, and stated preference tests, that ask respondents to report their attitudes and beliefs. But how can we measure our implicit perceptions, those that are rooted in our subconscious and outside of conscious awareness and control? Emily O’Donnell introduces the Implicit Association Test (IAT) as a novel technique to determine subconscious perceptions.

Understanding public attitudes towards Blue-Green infrastructure

To date there are relatively few academic studies of the public perceptions of Blue-Green infrastructure and SuDS (Sustainable Drainage Systems), all of which have used explicit measures to collect data. As an example, my colleagues on the Blue-Green Cities research project investigated the public perceptions of Portland’s (Oregon, USA) bioswales (Everett et al., 2018). They found that bioswales were generally regarded as aesthetically-pleasing but residents were concerned over ‘mess’ and littering, typically influenced by site-specific physical characteristics especially plant choice and maintenance regime (Figure 2). Concerns over the health and safety risk of SuDS, especially those with open water, have also been raised (Bastien et al., 2012), yet views of open water are highly valued with regards to aesthetics. We are interested to see if implicit perceptions can help explain these conflicting attitudes.

Figure 1. Portland’s bioswales – rich in biodiversity and attractive or unsafe and messy?

The Implicit Association Test (IAT)

The IAT is a social-psychology tool that may overcome some of the issues with explicit tests, particularly issues of social desirability bias where we report that we ‘like’ all greenspace and environmental initiatives as we think that this is more socially acceptable. IATs can also highlight attitudes that people were not aware that they had. IATs have been used in investigations of perceived environmental hazards such as nuclear power (Truelove et al., 2014) and climate change (Beattie and McGuire 2012). Table 1 highlights the key differences between explicit and implicit measures.

Table 1. Characteristics of explicit and implicit measures to determine preferences.

How Implicit Association Tests work

Implicit attitudes are calculated by measuring the strength of associations between target concepts (e.g. flower or insect) and attributes (e.g. positive and negative words). Participants are asked to complete several trials on a computer or tablet. During each trial, they will make pairings between images/words of flowers and insects, and good and bad words (the idea being that flowers are viewed positively and insects are viewed negatively). The test argues that an implicit preference is shown if the participants finds it easier (i.e. respond faster) to make certain associations (such as those between positive words and flowers).

Using the IAT in the Blue-Green Futures project

IATs have had little application in water management research to date. We are currently developing an online IAT to investigate implicit perceptions of Blue-Green infrastructure (e.g. bioswales, rain gardens, green roofs) vs. Grey infrastructure (e.g. pipes, storm drains, culverts). These will be completed by respondents in our four case study cities, so in order to reduce any language issues we are actually creating four online IATs – UK English, US English (subtle differences between UK and US English that may affect response times, e.g. ‘grey’ vs. ‘gray’, ‘green roof’ vs. ‘eco-roof’), Dutch and Chinese. We hope to establish if there are implicit attitudes to Blue-Green infrastructure that people might explicitly reject because they conflict with accepted values or beliefs. We plan to launch our online IATs in July.

If you are interested in the IAT approach then have a look at the Project Implicit website. There is a lot of information about this technique and the opportunity to complete IATs on a range of topics, e.g. age, gender-science, weapons and US presidential popularity.

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As the multiple co-benefits of Blue-Green infrastructure become more widely recognised and acknowledged, more and more cities are incorporating these approaches into their strategies to tackle environmental and social challenges. Emily O’Donnell explores further in this blog.

Multiple co-benefits of Blue-Green infrastructure

As an example, the Ningbo (China) Eco-Corridor project (led by the Ningbo Planning and Design Research Institution) uses Blue-Green infrastructure to transform a 3.3 km brownfield site into a ‘living filter’. This helps to manage the city’s flood risk while restoring ecosystems and creating better synergy between human activity and wildlife (SWA 2018).

Ningbo Eco-Corridor (photo: E. O’Donnell, June 2015)

In Leicester (UK) the Ellis Meadows scheme reduces flood risk to over 2000 homes and businesses, and was highly commended for best practice in large-scale practical nature conservation by the Chartered Institute of Ecology and Environmental Management (CIEEM). This again shows how Blue-Green flood risk management schemes may meet other city objectives, in this case, creating new habitats and enhancing biodiversity in an area of poor ecological value to help deliver the Leicester Biodiversity Action Plan 2011-2021.

As another example, many policies in Rotterdam (the Netherlands) over the last decade for strengthening Blue-Green infrastructure focus on how this may improve the quality of live in the city. The Rotterdam Waterplan 2 (2007) and subsequent Water Sensitive Rotterdam Programme (2015) use Blue-Green infrastructure to improve the cityscape and encourage interaction with water, while managing flood risk, improving water quality, and reusing rainwater.

These examples (and many others in cities worldwide) show that Blue-Green projects are definitely not restricted to just managing water and flood risk.

So who are the international Blue-Green infrastructure leaders?

The Blue-Green Futures project team are currently analysing the responses from a questionnaire exploring the perceived benefits, beneficiaries, multifunctionality and associated challenges of planning and delivering Blue-Green infrastructure. The questionnaire was completed by professional stakeholders in our four case study cities: Newcastle (UK), Ningbo (China), Portland (Oregon) and Rotterdam (the Netherlands). One question asked “Which cities are leading in BGI implementation?” The responses are shown in the figure below.

A word cloud detailing cities acknowledged by our questionnaire respondents as leading in Blue-Green infrastructure implementation.

Key trends

Portland and Rotterdam certainly stand out as cities acknowledged by many of our questionnaire respondents as BGI leaders. Portland; due to its extensive use of green infrastructure to manage stormwater and reduce combined sewer overflows (e.g. the ‘Grey to Green’ initiative), and Rotterdam; through its extensive research and investment into climate change adaptation and pioneering blue, green and grey infrastructure to manage risk and deliver benefits to society (e.g. the renowned Benthemplein Water Plaza).

The questionnaire responses suggests a lot of local support for Blue-Green infrastructure in Newcastle and the Chinese Sponge Cities. Other US cities – Seattle (Green Stormwater Infrastructure), Philadelphia (Green City, Clean Waters) and San Francisco (Green Infrastructure Projects) – are acknowledged as are cities further afield, including Singapore (Active, Beautiful, Clean Water Programme) and Melbourne (Green Infrastructure Projects).

Blue-Green infrastructure best practice is certainly evident on a global scale.

Follow our blogs for more insight into our research findings plus information on Blue-Green infrastructure progress, events and related research and practice.

The post Who are the international leaders in Blue-Green infrastructure? appeared first on Blue-Green Futures.

An exciting new international research project led by the University of Nottingham will focus on developing new Blue-Green futures for cities, where multifunctional infrastructure is used to address water challenges. This research is funded by the British Academy’s Tackling the UK’s International Challenges programme (January 2019 to July 2020). Emily O’Donnell gives a short introduction in this blog.

Blue-Green Futures

There is a recognised need for a fundamental change in how cities manage water in response to increasingly frequent and extreme rainfall events, drier summers and urban expansion. Approaches centred on ‘living with and making space for water’ are increasingly adopted internationally and address the full water spectrum (floods to droughts). These include the Dutch ‘Room for the River’ programme and Australian Water Sensitive Urban Design initiatives. These approaches are essential components of visions for Blue-Green futures.

What are Blue-Green Futures?

Futures that embrace Blue-Green principles are characterised by resilient and sustainable flood and water management approaches. Nature-based solutions, sustainable drainage systems (SuDS) and Blue-Green Infrastructure (e.g. green roofs, swales, rain gardens, detention basins and ponds) are widely employed. These approaches enrich society through the provision of multiple co-benefits. These include access to public greenspace, recreational opportunities, aesthetic enhancements, and improved management of environmental processes such as flooding, drought, urban heat, water and air pollution.

Project aim

This project brings together international researchers from three continents in a collaborative exploration of how the socio-political barriers to Blue-Green Infrastructure may be overcome to progress cities towards Blue-Green futures. Futures are founded on widespread implementation of infrastructure that creates multiple co-benefits to the environment, economy and society.

Through an analysis of explicit and implicit preferences and examination of how social learning may build capacity, we investigate how new forms of environmentally sustainable urban governance can be developed to address current water management challenges.

We focus on four cities that are known for their Blue-Green infrastructure advances yet have different governance approaches, challenges, perceptions and urban water narratives.

Figure 1. Our four international case studies. From top left and clockwise: sustainable drainage pond in Newcastle, green tram tracks in Rotterdam, the Ningbo Eco-corridor, and a school raingarden in Portland.

International case study cities

Cross-country learning on international best practices will be used to inform new Blue-Green futures and establish international benchmarks. We will focus on four case study cities and their existing Blue-Green visions (Figure 1);

• Newcastle (UK): Newcastle Declaration on Blue and Green infrastructure
• Rotterdam (the Netherlands): Rotterdam’s Urban Water Plans
• Ningbo (China): Chinese Sponge City programme
• Portland, Oregon (USA): citywide green infrastructure for stormwater management

We will explore how Blue-Green visions were developed in these cities, what the drivers for these were, and how learning could be applied in other cities.
 

Blue-Green Futures project team

UK: Simon Gosling (PI), Emily O’Donnell (researcher), University of Nottingham. China: Faith Chan (Co-I), University of Nottingham Ningbo China. USA: Noelwah Netusil (Co-I), Reed College, Portland Oregon. Netherlands: Nanco Dolman (Co-I), Royal HaskoningDHV, Amsterdam.
 

Keep in touch

We’ll be disseminating our research finding and other interesting papers on social media (follow us on Twitter @BlueGreenCities), this blog and future webinars. Subscribe to our blog updates to keep informed on our research progress.

We’d love to discuss paths to Blue-Green futures with you so please send us your thoughts via the comment box or Twitter.

For further information please contact Emily O’Donnell.

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