Diverse environmental performances of urban villages and insights for enhancing quality of urban renewal in Shenzhen

Abstract

As a prevalent neighbourhood type in contemporary Chinese cities, urban villages provide affordable housing and employment opportunities for low-income populations while also support the operation and development of cities. Shenzhen exemplifies this situation as the city’s urban villages currently house over half of its total population. However, over the past two decades, urban villages have been systematically demolished and redeveloped into high-rise low-density luxury compounds. Such mode of urban renewal has resulted in homogeneous city fabric, contributing to the degeneration of urban diversity and adaptability. One of the main cited reasons for the government, urban practitioners and even most environmental researchers to demolish urban villages is the so-called “poor” environmental qualities of the urban villages. Originated from former rural villages and with rapid urbanization and construction, the urban villages usually possess a high-density mid-rise pattern along with heterogeneous building layouts. The high density and irregular urban patterns of urban village are frequently cited as the main contributors to the environmental qualities in both academic literature and urban renewal policies. This dissertation makes a critical study of the demolition-oriented mode of urban renewal in Shenzhen and questions the problematically uniform pronouncements of the environmental qualities of urban villages. Through systematic on-site measurement, in-situ observation, and behavioral mapping, the research evaluates and compares environmental qualities of representative urban villages and urban (sub)neighbourhoods with daylighting and thermal comfort conditions as the key environmental indicators. In addition, the environmental performances in the redeveloped urban villages of Shenzhen are cross compared with their pre-demolition state through computational simulation. In recent years, the Shenzhen government has initiated a new direction of “Integrated Rehabilitation” of each urban village for future urban renewals instead of large-scale demolition. Under this circumstance, the investigation of relationships between urban morphological characteristics and environmental performances in urban villages and urban neighborhoods in this dissertation are of great significance for the formulation of more specific and detailed urban renewal strategies. This research reveals that morphological characteristics of each urban village play a critical role in influencing the environmental performance of the neighbourhoods, while the high-density mid-rise pattern does not necessarily lead to a decline in environmental quality. Although none of the detected morphological patterns in an urban village neighbourhood could continuously present good environmental performance at all times, the results demonstrate that urban villages present better environmental performances than the newly-built large-scale high-rise building blocks under extreme hot weather. The research presents merits and drawbacks of each morphological pattern in a specific time, and their timings are asynchronous but coherent. This leads to an understanding that the multiple morphological patterns in an urban village neighbourhood are environmentally complementary and have formed a synergetic network. These insights lead to a conceptualization of Shared Urban Ecologies, as the mixed-density pattern of each urban village neighbourhood encourages and enables the residents of the urban villages to have a continuous outdoor living space. This concept provides both spatial and environmental principles to form a Zoning Renewal planning and implement a more nuanced and detailed “Integrated Rehabilitation” of urban villages in Shenzhen. In conclusion, the environmental performance-based framework is suggested for policymakers and urban practitioners to recognize that urban villages not only contain productive and diverse socio-cultural resources but also have important environmental contributions to the living habitat of cities.