Green infrastructure provision for environmental justice: Application of the equity index in Guangzhou, China

Urban Forestry & Urban Greening 46 (2019) 126443

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Original article

Green infrastructure provision for environmental justice: Application of the equity index in Guangzhou, China Zhanqiang Zhua,b,c, Jie Rend, Xuan Liue,

T

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a

School of Geography and Planning, Sun Yat Sen University, PR China Guangdong Provincial Engineering Research Center for Public Security and Disaster, Guangzhou, PR China, 510275 c China Regional Coordinated Development and Rural Construction Institute, Sun Yat-sen University, Guangzhou 510275, China d Centre for Housing Innovations, the Chinese University of Hong Kong, PR China e School of Public Affairs and Administration, University of Electronic Science and Technology of China, No. 2006 Xiyuan Road, 611731, Chengdu, Sichuan Province, PR China b

A R T I C LE I N FO

A B S T R A C T

Handling Editor: J. Jun Yang

Following decades of debate, there is a growing consensus that environmental justice is an important value that should be pursued in green infrastructure (GI) provision, though there is a limited understanding of the precise ways by which to measure and respond to environmental justice needs. By developing a GI Equity Index that has been adjusted to reflect the local situation in Haizhu District in Guangzhou, this research examines environmental justice problems in respect to the provision of GI and proposes an amendment to the future GI plan. The integrated equity index map provides a comprehensive picture of the urgency of GI provision: Communities with the highest 20% equity index value are concentrated in the central part of Haizhu, which is a combination of an old city and villages. These areas are also where most of the urban waterlogging points are situated, and the loss would thus be greater. Unfortunately, these areas have been ignored by the Sponge City Plan of Guangzhou (2016–2030). This has led to a proposal in this research to adjust the GI plan: Additional green amenities should be provided in neighbourhoods with high GI equity index values. Such amenities could include small parks and playgrounds in densely developed central cities, or the replacement of impervious surfaces with permeable surfaces, etc.

Keywords: Environmental justice Equity index Green infrastructure Guangzhou

1. Introduction Environmental justice is defined as ‘the fair treatment and meaningful involvement of all people regardless of race, colour, national origin, or income with respect to the development, implementation, and enforcement of environmental laws, regulations, and policies’ (EPA, 2009). The focus on environmental justice in recent years indicates a global concern about equity challenges in relation to the distribution of environmental benefits and threats (Pickett et al., 2013). Less environmental amenities and a higher risk of environmental hazards in communities of colour or residents with fewer socio-economic resources have been widely reported around the world (Bullard, 2005; Downey, 2006; Mohai and Saha, 2007; Pellow, 2007). The situation is further worsened as affected communities of environmental injustice would seldom have an opportunity to participate in the decisions regarding the location of environmental amenities or exposure to environmental hazards (Cutter, 2006; Pena, 2006). Environmental justice began as a social movement in affected communities (Bullard et al., ⁎

2011), but there is a growing consensus that environmental justice, as a form of social equity, is an important value that should be strived for in terms of the provision of environmental amenities (Rigolon, 2016). In the field of public administration, social equity means that the benefits should be greater for the most disadvantaged but there is not an equal treatment for all (Denhardt and Catlaw, 2014), and public administrations must go further to ensure that public services are provided to those who need them the most (Frederickson, 2005). This is also what was targeted by environmental justice. As the most important environmental amenity within a city, green infrastructure (GI) plays a fundamental role establishing the overall environmental justice situation. The term ‘green infrastructure’ (GI) is often used broadly to refer to land uses including parks, street trees, greenways and sometimes private gardens (Heckert and Rosan, 2016; Xiao et al., 2016). GI indicates a network of green spaces that are multifunctional in terms of ecology, landscape, recreation, culture etc. (Hansen and Pauleit, 2014; La Rosa and Privitera, 2013; McMahon and Benedict, 2000; Xu, 2013). The concept derives from the greenway

Corresponding author. E-mail addresses: [email protected] (Z. Zhu), [email protected] (J. Ren), [email protected] (X. Liu).

https://doi.org/10.1016/j.ufug.2019.126443 Received 16 February 2019; Received in revised form 27 August 2019; Accepted 29 August 2019 Available online 29 August 2019 1618-8667/ © 2019 Elsevier GmbH. All rights reserved.

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movement in America (Benedict and McMahon, 2006) and was first applied in Maryland in 1999 to describe a better system of green space. GI targets were subsequently expanded further with the aim of combatting ‘urban diseases’ such as stormwater risks, heat island effects, and public health problems (McMahon and Benedict, 2000; Rouse and Bunster-Ossa, 2013; Coutts and Hahn, 2015). On the one hand, green infrastructure helps to create wind alleys, mitigate heat island effects, reduce the risks of waterlogging and flooding, etc. (Cowell and Lennon, 2014; Derkzen et al., 2017; La Rosa and Privitera, 2013; Norton et al., 2015). On the other hand, GI in cities also serves as an important component of public infrastructure, and has a positive influence on public health (Coutts and Hahn, 2015; Dobbs et al., 2011; Grahn and Stigsdotter, 2003; Qian et al., 2015; Shin et al., 2011; Yang et al., 2005) as GI ensures space for sports, facilitates social networks, and creates a sense of community (Comber et al., 2008; Wendel et al., 2012). The provision of GI is also perceived as helping to boost declining neighbourhoods through increased property values (Netusil et al., 2014). Taking the diverse benefits and cost effectiveness of GI (Jaffe, 2010) into consideration, urban leaders view GI as an important facility that can provide diverse co-benefits along with traditional services (Finewood et al., 2019). However, the provision of GI is also a field that encounters environmental justice-related problems. Recent studies reveal that GI may not be equally accessed by various social groups. Income, ethnic-racial characteristics, age (e.g., children (Cutts et al., 2009) the elderly (Kabisch and Haase, 2014; Yung et al., 2016)), gender, (dis)ability, unemployment, migration, and other demographic characteristics (Ode Sang et al., 2016; Wolch et al., 2014; Xiao et al., 2017) could substantially impact the chance of gaining access to GI. Studies have also found inequalities with respect to accessibility or the provision of green spaces in socioeconomically deprived and high-minority neighbourhoods (Boone et al., 2009; Dai, 2011; Heckert, 2013; Yin et al., 2008). Environmental justice must be taken into consideration in GI provision not only because of inequalities in relation to access to existing GI by vulnerable groups, but also because of the vulnerability of these groups when faced with environmental hazards, such as flooding, drought etc (Walker and Burningham, 2011). For instance, poor people are more likely to occupy housing that is least resilient to the ingress of water, are less able to afford products that can be installed to protect homes against flooding (Walker and Burningham, 2011), and are more likely to occupy an environment at a community level, in which the consequences of flooding are more serious (Few, 2003). Similarly, income and the status of caring for children are also recognized as important factors that affect an individual’s ability to adapt to flooding events (Masozera et al., 2007). To reduce the damage caused by natural disasters and to offer more protection to vulnerable groups, greater attention has been paid to promote environmental justice by arranging or adjusting GI provisions (Herk et al., 2011; Mees and Driessen, 2011; Zimmermann et al., 2016). Recently, with the support of GIS tools, a GI equity index has proven advantageous in helping to achieve an integrative goal based on the evaluation of environmental justice needs in the face of climate adaptation (Heckert and Rosan, 2016). This research attempts to adapt the GI equity index to the local conditions of a Chinese city (i.e., Guangzhou) and applies the equity index to the GI plan in Guangzhou. The remaining sections of this paper are organised as follows: The next section introduces the methodology that is utilised to develop the GI equity index, and the adjustment is presented to explain how the index can be adapted to the local situation. The index is then applied to study the provision of green infrastructure in Haizhu, an inner-city district in Guangzhou. These practices in Haizhu allow us to propose several suggestions aimed at adjusting the GI plan for Haizhu.

2. Provision for environmental justice: green infrastructure equity index 2.1. Green infrastructure equity index The green index is not a new issue. Scholars have long been aware that it is important to understand how GI investments are distributed across urban areas in order to promote environmental justice in the context of climate adaptation (Porse, 2018). Green indicators, such as the Normalized Deviation Vegetation Index and Urban Neighbourhood Green Index, have been used at street-level, neighbourhood-, and landscape-level scales (Li and Liu, 2016; Li et al., 2014; Liu et al., 2016; Mansor et al., 2017; Yao et al., 2014), and have indirectly revealed spatial inequality in respect to urban green spaces. However, most of these studies focus on the physical provision of greenery and seldom consider the needs of vulnerable groups, as well as on climate change issues such as rainstorms and flooding. In the meantime, new efforts seek to identify potential inequities with respect to access to green spaces, by different socioeconomic groups (Heckert, 2013; Hughey et al., 2016; Ibes, 2015; Shen et al., 2017; Xiao et al., 2017; Yin et al., 2008; You, 2016). Check-in records have been used to study spatial mismatches with regard to the accessibility of public green space, residents’ visits, and the demands of socially vulnerable groups (Shen et al., 2017; Xiao et al., 2019). These two research trends need to be integrated to identify an effective solution for the provision of future GI that considers both the risk of natural hazards and the vulnerability of certain social groups. Heckert and Rosan (2016) first applied the GI equity index in Philadelphia to discuss the ‘equity void ranking’ of all communities by assessing both built environment and socioeconomic variables. Heckert and Rosan accepted not only greenways but parks and other green spaces etc., as amenities that could provide environmental benefits as well as protect residents from stormwater. In the meantime, they used race or socio-economic status as markers of environmental justice. A total of 14 variables are included to assess disadvantaged areas, the concentration of vulnerable groups, exposure to environmental risks, and access to environmental amenities. This method offered an integrated evaluation of equitable GI provision in a given city. As a theoretical evaluation, the equity index can provide a tool to evaluate the need for GI provision in communities for both physically and socially vulnerable groups. Thus, it could offer useful guidance for GI planning within a city, especially for a city that is exposed to a high risk of flooding. 2.2. Need to adjust the equity index for the city of Guangzhou The equity index that is designed for the US could not be applied globally. The GI equity index aims to not only reduce cumulative sewer overflows and avoid the release of raw sewage into waterways, but also promote better distribution of green infrastructures for social equity. Therefore, the way in which floods cause damage to different cities and the distribution of social equity problems would inevitably influence the selection of variables that would be used in the Equity Index. Following the GI practices in the US and other countries, the first greenway network project in China was introduced in Guangdong Province in 2010 (Liu et al., 2018). The successful practice in Guangzhou became the best GI publicity. Thereafter, GI became the most important part of the ‘sponge city’ national project (Chan et al., 2018). Chinese governments expected that GI could help to achieve multiple targets, such as resistance to urban flooding, public health and recreation. This research aims to develop an Equity Index that is suitable for Guangzhou, a region that suffers heavily from waterlogging within the city after rainstorms, and green infrastructures are the main spaces that are used for recreation and sports. GI provision in Chinese cities is primarily characterized by a top-down systematic arrangement by governments, in which citizens do not play a significant role. If the 2

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faces problems of inequity in the provision of green infrastructure (Jiang et al., 2010a,b; Zhou et al., 2013). As shown in Fig.1, most green infrastructure facilities in Guangzhou are located near mounts and rivers as these locations enjoy more favourable natural conditions for plant growth. As more green infrastructure facilities are provided in places where high-end residences tend to concentrate, complaints about insufficient access to green infrastructure by low income population groups often appear in the newspapers and other forms of public media (Biswas and Hartley, 2017). Flooding and waterlogging after storms always generated complaints from communities within old towns that were directly affected by it, especially from disadvantaged groups (Sidner, 2017). It is evident that such groups should be better cared for, in light of social equity. Therefore, a new task for the local government and planning departments in Guangzhou concerns the way in which environmental injustice in the provision of GI can be measured so that the plan for green infrastructure could be adjusted accordingly. It is especially important for the newly established Guangzhou Water Affairs Bureau (GWAB). GWAB was established in 2009 and its aim was urban flood control and other water-related issues. With growing political concerns and limited financial resources, GWAB need a sound schedule to identify the priority of developing amenities to reduce the impact of floods, including GI.

design of GI does not adequately consider environmental justice or social equity, this could lead to greater environmental justice problems. In 2016, a total of 0.79 billion people were living in cities in China, representing 57.4% of the country’s population (National Bureau of Statistics of China, 2017). The cities in China are so densely populated that the provision of green infrastructure has become essential to making cities sustainable and habitable. Developing a better green infrastructure network also helps cities to adapt to climate change by mitigating the increasing prevalence of urban flooding and waterlogging, which is now a very serious water-related issue in Chinese cities (Chan et al., 2018; Francesch-Huidobro et al., 2016; Mguni et al., 2015; Yang et al., 2015). The development of urban GI in similar cities in China has been ongoing in response to flooding control targets, particularly since 2014, when the Chinese government adopted the ‘sponge city program’. Billions of dollars have been invested practically in GI in order to reinforce the cities’ ability to adapt (Bai, 2015; Biswas and Hartley, 2017; Huang et al., 2018; Jia et al., 2018; Nguyen et al., 2019; Workman, 2017). GI approaches that help to adapt to rainstorms and urban flooding, such as greenways, parks, waterfront areas, green roofs, bioretention (i.e., bioswales, ponds, biofilters or bio-gardens), urban permeable pavements, etc. are in the process of being constructed (Nguyen et al., 2019). However, the urban greening strategies, and the targeted mitigation of exposure to flooding and waterlogging among disadvantaged groups, have seldom been considered over the course of this surge in the provision of green infrastructure. Jiang et al. (2010b) found that high social-status and high-income groups enjoy greater accessibility to green infrastructure in Guangzhou. Poor levels of accessibility were found in the sub-districts inhabited by the elderly or unemployed residents in Shanghai (Shen et al., 2017). An urgent task for local governments in China is to find a more effective way to promote the equitable distribution of green infrastructure. As the third biggest city in China, Guangzhou city is confronted with the pressure of extreme rainstorms which is mainly caused by climate change (Francesch-Huidobro et al., 2016). For the period 2009–2016, Guangzhou experienced an average of six rainstorms per year and over 50 mm of rainfall in a six hour period, followed by long lasting urban waterlogging (Huang et al., 2018). Urban waterlogging points are mostly concentrated in densely developed inner city areas where more low-income groups are found. Further aggravating the environmental injustice problem, the provision of GI in Guangzhou has not been effective enough to reduce the damage caused by rainstorms for vulnerable groups. In fact, Guangzhou

2.3. Equity index adjustment for Guangzhou By aiming to introduce a set of equity indices for the provision of GI for Chinese cities based on local contexts, this research selects Haizhu district in Guangzhou as the study area in order to identify the local economic, social, and environmental factors that must be highlighted to pursue better protection from floods and waterlogging, and to achieve environmental justice through the provision of GI. A need-based definition of environmental justice is applied in this research. Two groups of factors were collected and evaluated, as shown in Table 1. The environmental factors group contains factors that demonstrate the physical distribution of GI, such as vegetation coverage, park accessibility, playground accessibility, vacant lots, and water surfaces. Each of the above variables represent a form of service provided by GI, which may help to counter the problems associated with flooding or waterlogging. Vegetation coverage helps to identify green space areas which play an important role as they facilitate water retention and are permeable areas that mitigate the risk of flooding and waterlogging exposure. Park accessibility highlights the important role

Fig. 1. The distribution of green infrastructure in Guangzhou and Haizhu District. 3

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Table 1 Green Infrastructure Equity Index and measurements. Category

Factor

Variable

Description

Expected impact

Environ-mental factors

vegetation coverage

score of dense vegetation

negative

park access playground access vacant lots water surface impervious surfaces

proportion of park proportion of playground proportion of vacant lots proportion of water surface proportion of impervious land population density Housing affordability proportion of children proportion of elderly people proportion of poorlyeducated people

Dense vegetation includes parks, residential green spaces, roadside green spaces, street-side green spaces. All are derived from high-resolution remote sensing image in 2012. percentage of 0.8 km buffer of parks to the total area percentage of 0.8 km buffer of playgrounds to the total area percentage of 0.8 km buffer of vacant lots of total area percentage of the water surface of the total area Impervious land consists of buildings, roads, or other paved surfaces based on high-resolution remote sensing image (2012) Population within a certain spatial unit housing rental prices percentage of children under 6 to the total population percentage of the elderly over 60 to the total population percentage of adults not completing high school based on the sixth national census (2010)

positive

Density Income Children Elderly poorly-educated

negative negative negative negative positive positive positive positive positive

Note: Expected impact indicates the potential contribution of a certain variable to the resulting Green Infrastructure Equity Index.

equity index is achieved by summing the non-weighted geometric mean of both the PN and PS value.

that parks play in environmental refuge, as well as decreasing the exposure to flooding and waterlogging. Vacant lots, which are normally permeable in China, are functional as they may potentially be used as facilities to retain water during rainstorms. Playgrounds play a role similar to vacant lots in the event of flooding and waterlogging. Moreover, they are also easily transformed into GI. Water surfaces may be viewed as containers for flood water. Impervious surfaces are also included to indicate the areas in which GI should be implemented, while considering the higher risk of loss in the event of flooding and waterlogging. The socio-economic factors group highlights the need for GI among people, especially for vulnerable groups. Inspired by the research carried out by Shen et al. (2017) and Xiao et al. (2017), and having considered the accessibility of data, we included the population density as well as the proportion of children, elderly people, low-income groups, and poorly educated populations. All of these variables are overlaid using equity mapping and a bottom-up GIS approach. Following the methodology proposed by Talen (1998); (2000), we determine technical flow using the following three steps: (1) normalization; (2) aggregation; (3) non-geometric mean. The first step is to conduct normalization on each factor to obtain comparable variables. In order to avoid the impact of magnitudes of various variables, we standardised each set of raw values (vegetation cover is excluded) to scores ranging from 0 to 1. With the exception of the vegetation cover factor, the scores of all other factors were standardised using the following equation: standardised score = (raw score - minimum value)/the range of existing values. We then assumed that ‘0′ indicated the least disadvantaged score and ‘1′ indicated the most disadvantaged. For the variables, i.e., income level, park access, playground access, vacancy rate, vegetation cover, road network density, and water area, a higher value indicates better provision or less of a need for GI. We subtracted the result from ‘1′ in order to maintain a score of ‘1′ that consistently indicated the most disadvantaged communities. We then calculated the index value by adding the standardised scores for each of the eleven variables and visualised the results using ArcGIS10.3 in order to obtain the map that illustrates need, while using a quantile classification (i.e., each of the five colours represents 20% of the communities). However, in terms of parks, playgrounds, vacant lots, and water areas, the method is slightly different because the number of communities that show a standardised score of ‘0′ or ‘1′ is above 20%. The second step aims to obtain an integrated potential supply (PS) of GI by aggregating all of the environmental variables, and an integrated potential need (PN) for GI by aggregating all socio-economic variables. Using this process, the bias, which is caused by an uneven number of environmental factors (n = 6) and social and economic factors (n = 5), is expected to be eliminated. Finally, the integrated GI

3. Case study: equity index evaluation of Haizhu District, Guangzhou 3.1. Quantifying variables for Haizhu district Assuming that there is a greater need for green infrastructure in communities with poor environmental conditions, the equitable distribution of green infrastructure should take into account the allocation and accessibility of environmental amenities and the risk of damage caused by a disaster. Hence, the environmental measures included: vegetation coverage, park access, playground access, vacant lots, water surfaces, and the scale of impervious surfaces. Standardized scores are used to evaluate the vegetation coverage. The National Garden City Standard in China set the minimum benchmark of dense vegetation provision at 36%. In this research, dense vegetation coverage of 36% or above is scored ‘1′. For communities with a coverage lower than 36%, the standardised score = (raw score - minimum value)/(36% minimum value). Following Heckert and Rosan’s (2016) study, we used the percentage of the 0.8 km buffer to the total area for variables including accessibility of parks, playgrounds, and vacant lots, and the percentage of water surfaces in the total area to evaluate how water surfaces may contribute to decreasing the damage that may be caused by floods. An arbitrary distance of 0.8 km (0.5 mi.) is regarded as acceptable and convenient. This size of buffer zone refers to area in which a certain facility, such as a playground or vacant lot, may play a critical role in the event of a rainstorm or waterlogging. The proportion of an impervious surface is defined as the area of the impervious surface in relation to the overall area within a certain census community. The selection of social and economic factors is based on the possible damage that could be caused by natural disasters. Population density is the first variable, since a population that is more affected means that a higher loss would be incurred in the event of flooding or waterlogging. Income level is used as the indicator to represent the socioeconomic background of citizens. Low income communities are confronted with a comparatively greater need to be close green infrastructures because low income citizens in these communities have few opportunities to drive to green infrastructure amenities. Furthermore, they often lack the resources to relocate to more affluent neighbourhoods where more amenities could be availed of (Heckert and Rosan, 2016). Due to the limitations of the census data (there is no income information in the sixth national survey in China), this study used housing rent to evaluate the income level of each community, following the example shown in existing research (Chen, Liu et al. 2016). For each community, we 4

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standardised scores for all the environmental variables (Fig. 3h), we found that the communities in the top 20% (i.e., those that have poor environmental conditions) are mainly located in central and western sections of Haizhu District. This means the green spaces are not adequate within the congested old city and villages. Inequality problems in the distribution of existing green infrastructure concentrates in several sections as the overlap ratio of the equity index, which assesses five environmental variables, is above 50%, except for the need value based on vegetation. Similarly, an obviously uneven distribution of social and economic needs is observed. The population is concentrated in the west area of Haizhu district and communities in the top 20% are situated along Jiangnan Avenue and Baogang Avenue (Fig. 4a). Twenty percent of the lowest income communities are situated in the north-eastern, central, and south-western sections of Haizhu district. However, 20% of the highest income communities are in the west and north (Fig. 4b). The top 20% of communities with adults without high school education and above are in the eastern and central section where villages and small industries such as knitting, processing and wholesales are concentrated (e.g., Kangle Village or Lijiao Village), or areas (in the east part of Haizhu) where big scale estate projects are under construction (Fig. 4c). The top 20% of communities with children under six years old are in the southwest and north (Fig. 4d). The top 20% of aging communities with adults over 60 years old are concentrated in the west area of Haizhu district (Fig. 4e). The top 20% of communities with better socioeconomic conditions were identified by summing all of the scores of socioeconomic factors. These areas with the lowest need for GI are mainly located in the northern part of Haizhu district, whereas the top 20% communities in a highest need are concentrated in the east or west (Fig. 4f). Following the technological flow chart (see Fig. 2), this research aggregates the equity index of environmental and socio-economic factors separately, and then integrates them into an integrated equity index. As shown in Fig. 5, the distribution of the integrated equity index indicates the following results:

multiplied the average rent by the average housing area to obtain the housing rent. The percentage of adults who did not complete high school, and the percentage of those under age 6 and over age 60 were also used to indicate the concentration of vulnerable groups. Children and the elderly are potentially more vulnerable to environmental justice issues due to limitations related to their age and mobility (Boone et al., 2009; Reyes et al., 2014). The readers of this paper may note that in China, it is widely accepted that the elderly population refers to those who are aged 60 years old and above (Shen et al., 2017). ‘Community’ in this research represents the spatial unit upon which census data are collected and all of the calculations are based. The data used in this study were obtained from the following sources: (1) demographic data and housing area data for 257 communities (census units) in Haizhu were extracted from the sixth Guangzhou Census of 2010; (2) housing rent data were obtained from a study of the spatial pattern of housing rent (Chen et al., 2016); (3) CAD land use map in 2015 in Haizhu; (4) vegetation coverage data were obtained from high resolution aerial remote sensing images of Haizhu in 2012 using eCognition 9.0. After proofreading the spatial land use data, remote sensing images, and the investigative report on the present situation, the data required for the research were generated using ArcGIS10.3.

3.2. Findings: environmental justice problems in Haizhu Haizhu District is in central Guangzhou, surrounded by the waterway of the Pearl River. GI in Haizhu District, such as wetlands, lakes, parks, and other forms of green land, have provided various ecosystem services and have offered recreation spaces to citizens which promotes social interaction. Moreover, Haizhu district has experienced the same situation as Guanghzou city in terms of rainstorms, and the flooding and waterlogging that results (Huang et al., 2018). Following the technological flow chart (Fig. 2), this research aggregates the equity index of environmental and socio-economic factors separately and illustrates the results in Figs. 3 and 4. An integrated GI equity index is shown in Fig. 5. Fig. 3 shows the distribution of environmental factors in Haizhu District which indicates the observed inequality in the provision of green infrastructure. In general, there is an over-provision of green spaces in eastern Haizhu, but an inadequate provision within the congested old city and villages. By overlaying

(1) There are obvious environmental justice problems in Haizhu District: the communities with the highest 20% of equity index values are mainly located in the central part of Haizhu, where there

Fig. 2. Technological flow chart. (a) Supply of vegetation (b) Supply of parks (c) Supply of playground (d) Supply of vacant land (e) distribution of impervious surface (f) Supply of water surface (g) integrative assessment of environmental factors. 5

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Fig. 3. Equity index of environmental factors for green infrastructure provisions. (a) needs indicated by population density (b) needs by low-income groups (c) needs by poorly-educated groups (d) needs by children under 6 (e) needs by older population (f) integrative assessment of socioeconomic factors.

relatively equal distribution of the urban sewage system, existing environmental justice problems related to GI provision should be blamed the most for the waterlogging problems in Haizhu. (3) In Haizhu, the GI equity index is more defined by environmental factors. Among the top 20% of in need communities (comprises 51 communities), 37 are among the top 20%, as shown in the environmental shelf index; and 22 are among the top 20%, as shown in social and economic need index. Only ten communities have simultaneous equality and equity problems. Among the top 20% of in

is a combination of an old city and villages. These areas include Fengyang Jiedao, Jianghai Jiedao, and Chigang Jiedao. Some other communities with high need values were in the northwest (such as Binjiang Jiedao and Sushe Jiedao) and Pazhou Jiedao which is in the east of Haizhu. (2) By overlaying the map of waterlogging points for the period 2009–2015 and the equity index map (Fig. 6), one could easily observe that areas with highest need for GI are also those where most urban waterlogging points are located. Considering the 6

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Fig. 4. Equity index of socio-economic factors for green infrastructure provisions.

spatially locating green infrastructure, which may contribute towards achieving environmental justice. Using this spatial guide, measures to increase green infrastructure could be applied precisely, and could be tailored to reflect the unique character of different locations. This research suggests that areas with the highest equity index value (20%) should be given priority for future GI provisions. This suggestion is also proposed for the review and adjustment of the Sponge City Plan of Guangzhou (2016–2030). The Sponge City Plan of Guangzhou (2016–2030) was issued in 2017 by the Municipal Bureau of Land Resources and Planning to locate all of the natural reservation areas and cleaning points for a sustainable city. Such facilities include sponge parks, wetlands, sponge green belts etc. that help to improve the city’s ability to adapt to flooding. A comparison of the area with a higher equity index value and new provisions of natural reservation areas and

need communities, only 14 are among the top 20% of low-income communities, 14 are among the top 20% of poorly educated people, 13 are among the top 20% of aging communities, and nine appear in the top 20% of communities with children under six years old. (4) Pazhou Street Community has a large proportion of agricultural land and water areas, though still suffers from high GI equity index values. This finding indicated that productive green land did not represent an adequate substitute for green infrastructure, especially for vulnerable groups. 4. Application of the equity index for urban planning in Guangzhou This case provides one of the most effective mechanisms for 7

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Fig. 5. Distribution of integrated equity index of communities in Haizhu.

also include improving accessibility to existing parks and playgrounds by adopting a comprehensive traffic upgrading strategy. 2) In communities with a high density of buildings and intense land use, where it is difficult to provide new large public green spaces, other greening strategies, such as roof greening, vertical greening, parkways, and greenways, are recommended to create better green space access and greater opportunities for residents' daily recreation (Haaland and van den Bosch, 2015). 3) It is also recommended to redevelop sections of hard surfaces, such as parking lots, create permeable surfaces. Such measures can

cleaning points shows an obvious mismatch in GI provision and environmental justice needs (Fig. 7). Most new amenities have been provided in suburban areas with little consideration for the environmental justice needs that concentrate in the central areas. To provide GI more effectively, this research proposes the following measures to minimise environmental justice problems. 1) In communities that have enough space, measures could be taken to increase public green space amenities, such as the development of small green spaces, open water areas, parks, etc. Measures would

Fig. 6. Overlaid equity index map showing the top 20% in need areas and waterlogging points in Haizhu District. Note: the shaded areas show the kernel density of waterlogging points: The darker the colour of the area, the greater the number of waterlogging points. 8

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Fig. 7. Mismatch between environmental justice needs and GI provision in the Sponge City Plan (2016–2030).

high GI equity index values, indicating that such areas could not replace the role of green infrastructure, especially when considering people’s needs for GI for relaxation and recreation. These findings led us to propose the need to adjust the Green Infrastructure Plan of Guangzhou: more green amenities should be provided in neighbourhoods with high Green Infrastructure Equity Index values. Such amenities may include small parks and playgrounds in densely developed central cities, or the replacement of impervious surfaces by permeable surfaces, etc. The integrated equity index map offers a big picture of the urgency of GI provision throughout all neighbourhoods and a more rational timetable for in-depth surveys and construction could be achieved. Furthermore, in respect to the study of GI provision, the effectiveness of the equity index for environmental justice suggests a new way of measuring social equity needs for the provision of public services, especially for those services which largely define their effectiveness in terms of their level of accessibility to venues that provide public services. Recent studies have begun to pay attention to the way in which social equity is measured (Regens and Rycroft, 1986) (Ringquist, 2005), and have sought to take social equity into account when considering the distribution of public funds or programs (Collins and Gerber, 2008). The design of an equity index for public services could also include variables such as the proportion of the public budget that is designated to vulnerable groups and the number of volunteers that help vulnerable people etc., to highlight and illustrate the need for certain public services. However, the equitable physical distribution of GI is just one component of environmental justice. A more important component involves offering a greater opportunity for vulnerable groups to participate in the process and influence the decision making for GI provision. In other words, the study of the equity index should occur in conjunction with public participation, especially the participation of vulnerable groups, to achieve an overall target for environment justice. This research also suggests that greater attention should be paid to justice-related concerns involving the fairness of processes. This can include both the injustice of the process and the results.

facilitate better absorbability and the reuse of rainwater. 4) Measures should be taken to help improve the quality of existing facilities and their service capacity. Such measures may include improving water quality, dredging river channels, reforming drainage pipe facilities, upgrading the existing park environment, and so on. 5) The area with highest equity index value should also be prioritised first for future in-depth surveys and public participation to evaluate the specific needs of the community for GI provision. 5. Conclusion and discussion After decades of debate, there is a growing consensus that environmental justice is an important value that should be pursued by the public administration. Having carried out a literature review of this issue, it is clear that the equitable distribution of green infrastructure has not yet been considered systematically, though it is vital for a city to be more resilient and humane when faced with the threat of extreme weather, especially floods. Taking into consideration the important role that GI provision plays in establishing the overall situation of environmental justice, this research tries to adapt the GI equity index to the local conditions of a Chinese city, i.e., Guangzhou, to measure environmental justice needs in respect to the provision of green infrastructure and proposes an adjustment to the future green infrastructure plan. The results of this research highlight that environmental justice problems could be evaluated by employing a scientific design of a GI equity index and may be solved by an adjustment to the GI plans, accordingly. In Haizhu District, it is revealed that: (1) There are obvious environmental justice problems in Haizhu District: the communities with the highest 20% of equity index values are mainly located in the central part of Haizhu, where there is a combination of an old city and villages. (2) Unfortunately, these areas are also where most urban waterlogging points are located. Considering the relatively equal distribution of the urban sewage system, the existing environmental justice problems that are associated with GI provision should be blamed the most for the waterlogging problems in Haizhu. (3) Neighbourhoods with large water surfaces and less impervious surfaces may still have 9

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