Designing liveable urban open spaces in high density cities

Abstract

Hong Kong is one of the densest cities compared to other metropolitan cities with population density in some districts exceeding 57,250 persons per sqkm. Hong Kong’s liveability has been affected by factors such as escalating urban density, lack of open spaces, congested living environments, air pollution concentration and high proneness to pandemics.Due to extremely high land premiums, some residents in Hong Kong live in nano flats small as 15sqm in high-rise towers. Given the congested nature of apartments, open spaces a play a vital role contributing to residents’ psychological and physical well-being. Due to peculiar topography and extreme high density, Hong Kong open space per capita is far from the WHO recommended standards of 9 sqm per person. Most urban open spaces are pocket spaces located among developments or adjacent to traffic roads with a high ratio of hardscape compared to vegetation. Due to challenging Summer conditions in Hong Kong with high temperature, humidity and stagnant wind most urban open spaces are underutilized.This research investigates the factors effecting enjoyment of open spaces and design factors that could contribute to improve their liveability as public amenities. Exploration is based on liveability parameters such as user comfort, user behaviour, and spatial attributes of urban open spaces. Field data was collected on seven urban open spaces within Tsuen Wan district during dry Summer days. Field data analysis was supplemented by simulation methods, photographic survey of users’ movement within open spaces and user interviews.All open spaces are located amidst of high-density urban environment facilitating easy access to residents in the neighbourhood proving sense of security. Findings indicate tendencies in using these open spaces in the afternoon after 4pm when these open spaces cool off from solar radiation. Majority of open spaces benefited from shading effect from surrounding buildings, however the seating arrangements have not benefited from the shading. Satisfactory wind speed could be observed in four open spaces out of the seven that benefited from South and SE wind directions providing desirable thermal comfort to users. The park that consisted of the highest ratio of greenery received the lowest wind speed due walled effect created by surrounding buildings. Ironically open spaces with high percentage of hardscape areas reported better wind performance indicating the possibility of high emissivity material creating low pressure pockets drawing winds in particularly in the afternoons.