City and Environment Interactions最新文献

Shacks in urban informal settlements will be the most common form of housing in Namibia by 2025. Informal settlements are usually not connected to municipal sewage systems for multiple reasons, including lack of land tenure and lack of official capacity to invest in infrastructure in unplanned spaces. On-site decentralised sanitation is therefore the norm for shack dwellings in Namibia, but any official opposition to this system results in complete absence of sanitation and inadvertently promotes open defecation. This grey zone of urban informality and the gap in sanitation delivery is the focus of this study, which evaluates interactions between local communities, non-government organisations (Clay House Project and Development Workshop Namibia) and an international development agency (GIZ) as they navigate the physical, economic and political landscape of implementing bottom-up sanitation solutions for informal settlements in Namibia. In critical analysis of the three different sanitation delivery models of these organisations, we consider their historical development, underlying philosophies and technical solutions. We also examine how products from different sanitation systems are managed and whether urine source separation could improve their management. Overall, the results provide insights into bridging gaps in sanitation delivery in informal settlements, which are home to more than a billion people worldwide.

Large-scale, centralised sanitation systems provide safe, reliable, affordable and dignified sanitation to those located within the waterborne sewerage network. However, publicly managed hydro-modernist sanitation systems are not available to all, with many households and communities across the world having to access basic off-grid, state-provided sanitation services, such as pit latrines or Urine Diversion Dehydration Toilets, or having to provide their own solutions to sanitation waste. Urban green sanitation, which is non-sewered and off-grid, represents a new form of hydro-social and socio-technical relations. It aims to address sanitation backlogs and provide an alternative to centralised sanitation systems using ecological circularity. This paper categorises the social acceptability of urban green sanitation technologies into four main dimensions: social concerns, environmental concerns, the right to sanitation, and making a contribution to change. It draws on social assessments undertaken between 2016 and 2023, for the testing of sanitation technologies in Durban, South Africa, as part of the Engineering Field Testing Platform funded by the Bill and Melinda Gates Foundation’s Reinvent the Toilet Challenge and the Water Research Commission, South Africa, to reflect on the social dimensions of urban green sanitation. It argues that transdisciplinary research approaches and the co-production of knowledge are essential in understanding the social acceptability of green sanitation.

Modeling and prediction of mode choice are essential to support more sustainable and safer transportation decisions. There is plenty of literature in this decade showing that machine learning (ML) models have been effective predicting techniques, although not easily interpretable. When these techniques are used, there is a lack of connection with the data-gathering step, which is crucial to the technique selection and appropriate analysis of results. Based on a systematic literature review on mode choice studies, we present a methodology that interconnects the data-gathering process as a fundamental part of the descriptive phase when ML classification methods are used to predict mode choice preferences. The case study presented occurs in a university context whose descriptive phase shows interesting behavior patterns and highly imbalanced data in terms of mode choice. We show how decision tree methods allow us to tackle this issue in a contextualized manner and permit sensitivity analysis to test policies promoting changes in the modal split that aim for more sustainable mobility for the community of the university.

Downscaling is a particularly needed process in many environmental, social and governance applications at the fine scale. The need for an automated and reliable very high spatial resolution downscaling approach is then required. In this paper, a fully-automated open-access downscaling approach was proposed, named HSR-LST. It is based on the High Spatial Resolution (HSR) Red, Green and Blue (RGB) bands collected from commercial and free-to-access satellite images, generating LST values lower than 2-m spatial resolutions. This is based on the Landsat-8 thermal datasets and while implementing a fully-automated Ordinary Least Squares (OLS) approach. HSR-LST was implemented over Beirut, Boston and Dubai between 2016 and 2018. In comparison to an airborne LST image captured over ElKhorn River in Nebraska, USA, HSR-LST showed an AME of 0.88 °C and a R-squared value of 86.33%. Main results showed the variability of LST based on the sensed land features’ type. Different LST distribution footprints (i.e., irregular in Beirut, intermitted in Boston, systematic in Dubai) were highlighted depicting a characteristic urban configuration in each city. This latter along buildings’ material, density and height appear also to show a different effect on the local and surrounding LST values. By implementing the automated HSR-LST model in cities around the Globe, urban planners, policy makers and inhabitants can acquire improved information to assess urban heat islands, to propose more adequate planning policies, but more importantly to tackle urban heat and thermal comfort at the finest scales. HST-LST will effectively address the low spatial resolution of thermal bands. As HSR-LST is both automated and dynamic, it can be portable to other urban areas with diverse climatic regions.

Urban Flooding represents a significant problem in developing urban areas caused by inadequate stormwater drainage systems, increased impervious surface areas, and climate change. The performance of drainage systems can be evaluated using simulation models such as the stormwater management simulation model (SWMM). In this study, the potential impacts of future design rainfall on the performance of stormwater management systems were assessed by altering a hyetograph derived from rainfall intensity duration curves from three climate models. In addition, the effects of continued urbanization on the systems have been simulated by changing the percentage of imperviousness from current land use conditions. According to the findings, existing drainage systems cannot manage the expected flooding risks caused by a slight change in future rainfall intensity under each climate model. As a result of urban development, increasing the imperviousness ratio from 10% to 70% has increased peak runoff from 51.3 to 82.4 m³/s, flooding volume amplified from 24,320.5 x10³ to 33,647.4 x10³ m³ (representing 38.4% of the increase), and flooded nodes risen from 64 to 196 (representing 67.12% of raise). Overall, flooding locations and magnitude were identified, while drainage systems failed to safely convey surface runoff at baseline conditions, implying that future flooding will be more intense. As a result, selected mitigation strategies should be considered to alleviate the flooding risks that disrupt the socio-economic environment and the resulting significant property and life losses in Dodola, Ethiopia.

The world’s population is estimated to reach 11 billion in this century, with some 8.5 billion living in urban areas. Cities become unprecedented hot spots of demand for virgin water and food, as well as producers of large volumes of valuable waste. The recycling of urban nutrient-rich liquid and solid waste as fertilizer in agriculture will thus be of benefit to both sectors. The analysis suggests that recycling has the potential to become the ultimate sink for organic waste and wastewater, while simultaneously securing the supply of food and fertilizers, and reducing both local and global environmental impacts. Presently, harmful chemical substances from various consumer products in our chemical society are disposed of in urban waste flows and hamper recovery and reuse. A combination of counter measures such as not mixing nutrient-rich blackwater with grey water polluted with chemical compounds, are crucial. The sludge from the small volume of blackwater can contribute enough fertilizers to secure global food supplies by the year 2100. The voluminous grey water will contain few pathogenic microorganisms and can be treated for non-potable reuse. Three urban arrangements are analysed: Singapore (entire city), Helsingborg in Sweden (city district), and Bangalore in India (eco-house).

Although flush toilets and sewerage are usually considered the height of comfort in 21st-century urban societies and the technical and sanitary culmination of human excreta management, they are increasingly being challenged for their environmental footprint and financial cost. Alternative management methods, broadly termed “source separation”, are being developed to address these issues. However, the widely shared belief in the absolute superiority of sewerage for public health is hindering the development of such systems. In this paper, we briefly re-examine the contribution to public health of sewerage as a means of managing human feces, in both its historical development and current implementation. We suggest that management of feces by sewerage is just one element among others in a systemic change, that it usually occurred much later than the others, and that the epidemiological transition usually attributed to sewerage only was, as a matter of fact, strongly supported by associated improvements in drinking water, health care, hygiene practices and good nutrition. We show that risk control in sewered cities is not based on a barrier between human feces and the environment (what we might call sanitation), but on barriers between a contaminated environment and the different uses of water. We call for a more comprehensive analysis of the effects of sewerage on public health, in present times and historically, not only at the scale of a city but at the broader scale of all impacted communities. We also call for a comparison of these effects with those of other sanitation systems that have much lower environmental footprint.

This paper investigates the use of a citizen science approach for air quality monitoring to explore the likely pollution impacts of the new Missing Link #12 road passing through the informal settlement of Kibera, within Nairobi. Citizen science approaches are gaining relevance in air quality monitoring thanks to the advancement in environmental monitoring technology and the opportunities created for community-based organizations to collect data on air pollution through low-cost sensors. Fourteen households located in proximity to the Missing Link#12 were equipped with optical particle sensors. Data collected indicated that people living along the road are exposed to levels of PM_2.5 and PM₁₀ above WHO recommendations, mainly due to the particulate generated by the construction site and fuels used for indoor cooking. A community engagement workshop revealed that participatory approaches are useful for improving awareness of air pollution and associated health implications. It also allowed the community to enhance their capability to gain and use scientific tools to address local issues, and potentially lobby decision-makers to solve them. In the context of transport infrastructure development in African cities, such an approach can be a means of collecting data and monitoring the impacts of air pollution during and after road building.

Perched on the edge and corner of the city center, pocket parks transform urban vacant land into vibrant urban oases. It can greatly shorten the distance from citizens to the park, thereby promoting citizens' participation in outdoor activities and improving urban vitality. The construction of pocket parks in China started late. However, it has developed rapidly in recent years, which supports urban regeneration. A government document, published by the Ministry of Housing and Urban-Rural Development of the People’s Republic of China in 2002, promotes the construction of pocket parks. In the process of promoting the construction of pocket parks in Chinese cities, problems such as unclear construction standards, difficult operation and maintenance, blind copying, and emphasis on the landscape over the function have emerged. The aforementioned issues are elaborated and corresponding suggestions are pointed out in this short communication.