Advancing urban metabolism studies through GIS data: resource flows and stocks, geography, and informality in Mexico City

Urban Metabolism (UM) studies have evolved in recent years by adopting an interdisciplinary and multiscale approach of urban systems and paying increasing attention to socioeconomic contexts, relations of power among stakeholders, and the study of the ecology of entire urban areas. Localizing and quantifying urban flows and stocks could be of great value to identify infrastructure deficiencies and unequal access to resources for vulnerable population groups and in deprived urban areas. However, only a few studies provide spatial-explicit accountings of UM flows (e.g. Yeoh and Cheah, 2019), which can contribute towards more resource-sensitive urban planning. Mexico City is a city-region that includes 16 municipalities with a total population of approximately 8,9 million. An estimated 3,4 million residents live below the poverty line in high-density neighborhoods with limited access to facility and green spaces (with 160 thousand classified as informal, unregistered, population). Based on the results of previous UM studies (Guibrunet et al, 2016; Delgado-Ramos, 2015 and 2013; Kennedy et al, 2011; Hoornweg et al, 2011; Rossi et al, 2008), Mexico City provides a valuable case study due to the complex relations that were observed between resource accessibility, stock efficiency and the management of in-boundary resource flows. The aim of the research is to understand what kinds of data are better suited to improve the visualization of UM assessments and to identify the relationship between specific urban flows and public space. The following spatially-explicit datasets were used in the study: (1) utility infrastructure and resource-management facilities (e.g. energy lines, water distribution and sewage network), (2) geographic features of the city (e.g. topography, landscapes) including green and blue infrastructure networks, and (3) informal settlements and their sociodemographic characteristics. Additionally, UM data sourced from recent studies were allocated spatially. After visualizing the selected GIS data at the city-region level, a series of hotspots were identified, e.g. urban areas with a high concentration of public space, informal settlements and resource-management facilities. The hotspots were categorized by their land area and use type as well as by the quantity and quality of the elements they are physically connected with (e.g. number and type of public space and resource management facilities). The results highlight systems of urban flows and stocks circumscribed within different municipality boundaries and their links to the network of public spaces at the regional scale. It emphasizes inequalities in terms of accessibility to public spaces and resources among different municipalities and can suggest spatial design and planning strategies to mitigate them. The research also provides an improved understanding of the metabolic profiles, physical characteristics, and development opportunities of informal settlements in Mexico City concentrated between the built environment and regional nature reserves. The findings of this study can inform urban and landscape planners as well as UM analysts to formulate and apply landscape infrastructure design strategies based on a multi-scale, spatial-explicit approach. It suggests the need for further research on integrated UM and GIS analysis as a way forward to improve UM application in urban and landscape planning