Harnessing the runoff reduction potential of urban bioswales as an adaptation response to climate change.

Nature-based solutions (NbS), including China's Sponge City Program (SCP), can address the challenges urban communities face due to surface runoff and flooding. The current capacity of SCP facilities in urban environments falls short of meeting the demands placed on communities by climate change. Bioswales are a form of SCP facility that plays an important role in reducing surface runoff by promoting infiltration. This study assesses the potential of SCP facilities to reduce runoff in urban communities under climate change using the storm water management model. The study site in Ningbo, China, was used to evaluate the potential role of bioswales in reducing runoff risks from climate change. We found that bioswales were most effective in scenarios when rainfall peaks occurred early and were less effective in right-skewed rainfall events. The overall performance of SCP facilities was similar across all climate scenarios. To maintain the current protection level of SCP facilities, bioswales would need to cover at least 4% of the catchment area. These findings from Ningbo provide a useful method for assessing NbS in other regions and indicative values for the increase in the bioswale coverage needed to adapt to climate change.

A lack of focus on data sharing, stakeholders, and economic benefits in current global green infrastructure planning.

Green infrastructure (GI) is increasingly popular in solving urban environmental challenges and enhancing ecosystem services. Yet the research status and challenges of GI planning have not been comprehensively benchmarked to date. We explored the GI types, actions, goals, and spatiotemporal characteristics of GI planning cases worldwide based on the available literature. The challenges of GI planning were also investigated by the cases included in this manuscript. Additionally, the urban governance solutions to address these challenges were proposed. We found that multi-type GI planning is the most popular. Data sharing, stakeholder participation, economic benefits and research funding for GI planning research were generally inadequate, although they have improved trend over time. Multiple-goal GI planning frequently has higher levels of data sharing, stakeholder participation and economic benefits than GI planning that just takes into account one purpose. We conclude that the future transformation of GI planning requires efficient data sharing mechanisms, effective co-design among stakeholders, systematic business models, and available research funding.

Lifestyle and language barriers influence community engagement with green infrastructure.

Few studies have focused on value structures, experiences, and cultural diversity as it relates to bioswale planning and implementation. We used 'Point of Opportunity Interactions' to understand previously undocumented views of the Cantonese-speaking immigrant community regarding bioswale design and use for stormwater management in Portland, Oregon, USA. Approximately half of participants were not aware of bioswale function. Maintenance costs and aesthetics were noted concerns, but parking and safety were not. Lack of outreach materials in the Chinese language(s), evening and weekend work schedules, and lack of clarity about maintenance responsibility were among barriers to public participation. Overall, lack of trust for the city and city officials was apparent, and hindered outreach and engagement. Emphasis on informality and place-based data collection near bioswales as neutral outdoors spaces, and proximate to participant residences, facilitated communication with this 'hard-to-reach' population and revealed information that would have gone unknown using traditional outreach strategies.

Improving urban flood resilience via GDELT GKG analyses in China's Sponge Cities.

Urban floods are the most severe disaster in most Chinese cities due to rapid urbanisation and climate challenges. Recently, media data analytics has become prominent in enhancing urban flood resilience. In this study, news media data from the GKG of the GDELT project was innovatively used to examine the pattern of news media responses towards urban flooding in China's Sponge City Programme (SCP) pilot cities. We find that public sentiments toward urban flood events have been more positive in SCP pilot cities from 2015 to 2021. News media responses towards urban floods exhibit strong seasonality, which is significantly connected with rainfall patterns. Most of the media articles were posted during the urban flood event. Finally, we suggest the opportunities and challenges in applying GKG data analytics and new technologies for urban flood resilience. The results can provide beneficial references to urban flood management strategies in China's Sponge Cities for associated policymakers and stakeholders.

Determining the drivers and rates of soil erosion on the Loess Plateau since 1901.

Attributing soil erosion to land management and climatic drivers is important for global policy development to protect soils. The Chinese Loess Plateau is one of the most eroded areas in the world. However, there has been limited assessment of historic spatial changes in erosion rates on the Loess Plateau and the major contributors driving these spatial changes. In this study, the Revised Universal Soil Loss Equation was empirically validated and employed to assess spatially distributed historical erosion rates on the Loess Plateau from 1901 to 2016. A double mass curve attribution technique was then used to investigate the impact of land management and climatic drivers on the Loess Plateau. Decadal average erosion rates and the total area with intensive erosion (>5000 t km-2 yr-1) experienced a sharp increase from the 1930s to 1970s, followed by a decline to an historic low between the 1980s and 2000s. Mean erosion rates for the 2000s were 54.3% less than those of the 1970s. However, a recent increase in erosion rates was observed between 2010 and 2016. Land management change was the dominant driver of historical erosion rate changes before 2010. Extensive deforestation and farming, driven by population increase, were responsible for intensifying erosion between the 1930s and 1970s, while policy-driven conservation schemes and revegetation led to reduction thereafter. However, the recent increase in erosion between 2010 and 2016 was mainly driven by extreme rainfall events, a major concern given climate change projections. Advanced erosion control strategies are therefore required as part of integrated catchment management that both maintain water supplies for human use during dry periods while reducing erosion during storm events.

Evolving framework of studies on global gulf ecosystems with Sustainable Development Goals.

Gulf ecosystems provide many beneficial services to humanity and play a key role in achieving the Sustainable Development Goals (SDGs). However, the sustainability of gulf ecosystems has been severely threatened by climatic and anthropogenic stresses. Using network analysis of article records downloaded from Web of Science, we summarize the current research framework of gulf ecosystems via the perspectives of research themes, interdisciplinarity, and international collaborations. Research themes involve nutrient and eutrophication, biodiversity, mangrove and sediment pollution, and ecosystem service and climate change. Nevertheless, these themes usually focus on gulf ecosystems themselves with little consideration of their connectivity with other ecosystems. Interdisciplinarity has remained mostly within natural sciences while international collaborations exist mainly between developed and developing countries and among developed countries. Combined with the SDGs, we propose the future research framework where research themes should consider the impacts of terrestrial and freshwater ecosystems on gulf ecosystems at the watershed scale. Interdisciplinarity between natural and social and management sciences needs to be promoted by utilizing the advantages of data sciences. Collaborations with developing countries led by China, Mexico, Brazil, and India need to be strengthened. The evolved research framework could offer decision support for stakeholders to manage gulf ecosystems and achieve the SDGs.

Potency of the pandemic on air quality: An urban resilience perspective.

Since the outbreak of COVID-19 pandemic, the lockdown policy across the globe has brought improved air quality while fighting against the coronavirus. After the closure, urban air quality was subject to emission reduction of air pollutants and rebounded to the previous level after the potency period of recession. Different response patterns exhibit divergent sensitivities of urban resilience in regard to air pollution. In this paper, we investigate the post-lockdown AQI values of 314 major cities in China to analyse their differential effects on the influence factors of urban resilience. The major findings of this paper include: 1) Cities exhibit considerable range of resilience with their AQI values which are dropped by 21.1% per day, took 3.97 days on average to reach the significantly decreased trough point, and reduced by 49.3% after the lockdown initiatives. 2) Mega cities and cities that locate as the focal points of transportation for nearby provinces, together with those with high AQI values, were more struggling to maintain a good air quality with high rebounds. 3) Urban resilience shows divergent spatial sensitivities to air pollution controls. Failing to consider multi-dimensional factors besides from geomorphological and economical activities could lead to uneven results of environmental policies. The results unveil key drivers of urban air pollution mitigation, and provide valuable insights for prediction of air quality in response to anthropogenic interference events under different macro-economic contexts. Research findings in this paper can be adopted for prevention and management of public health risks from the perspective of urban resilience and environmental management in face of disruptive outbreak events in future.

Synthesis of dominant plastic microfibre prevalence and pollution control feasibility in Chinese freshwater environments.

Microplastic pollution of freshwaters is known to be a great concern in China and these pollutants can be discharged into the coastal environment through fluvial processes, posing threats to the global marine ecosystem. This paper reviewed the literature measuring microplastic pollution in the Chinese freshwater environment and found that microfibres dominate other plastic morphologies in more than 65% of samples collected in surface water, sediments and effluents of wastewater treatment plants and domestic sewers. Current potential sources of microfibre pollution are identified including fishery activities, laundry sewage, and waste textiles according to previous research. Recommendations are offered using the circular economy management framework, such as textile waste reuse and recycling systems in China, for improving current control measures for microplastics in freshwaters.

Interpretation and application of Sponge City guidelines in China.

'Sponge City' is the term used to describe the Chinese government's approach to urban surface water management. The concept was conceived in 2014 in response to an increasing incidence of urban flooding or water-logging in Chinese cities. While ambitious and far-reaching in its aim (of decreasing national flood risk, increasing water supply and improving water quality), the initiative must be implemented by individual subprovincial or municipal-level government entities. Thus, while the concept is similar to sustainable drainage systems (SuDS) in the UK (or low-impact development (LID) in the USA), it is developing with different regional characteristics, and during continuing rapid urbanization. Indeed, the increasing use of national rather than international examples of best practice reflects a growing body of knowledge that has evolved since the start of the Sponge City initiative. In this paper, interpretation and development of the national Sponge City guidelines are assessed for the Ningbo Municipality, an affluent and rapidly expanding city on China's low-lying east coast. While climate, geology and socio-economic factors can all be seen to influence the way that national guidelines are implemented, project financing, integration and assessment are found to be of increasing influence. This article is part of the theme issue 'Urban flood resilience'.

Reach-scale variation surface water quality in a reticular canal system in the lower Yangtze River Delta region, China.

The aim of this research was to assess the spatial and temporal distribution of surface water pollution within a reticular canal system typical of those found in the lower Yangtze River Delta (YRD). For this purpose, surface water quality data was collected from a drainage canal that bisected the southeast district of Ningbo Municipality (Zhejiang) from 2013 to 2015. The sampling transect was designed to represent the change in land-use from the agriculture dominated rural hinterland, to the predominantly urban city-centre. To calculate the representative land-use fraction of each sampling location, the contributing area was defined using an uni-directional 1 km vector line-buffer around the 'upstream' section of canal. The spatial and temporal variation of EC, DO, NH3 and turbidity indicated a measureable difference between the urban and rural sections of the channel. Water quality indicators were most sensitive to urban and parkland land-use types. The study yielded an increased spatial resolution to knowledge of water-quality variability in the urban environment compared to previous studies within the YRD region. The results were used to make recommendations for the development of an effective long-term strategy for the improvement in surface water quality in this region.