100 Hub: A New-Town Proposal for Hong Kong as a Model for High-Density Sustainable Cities
BY JOHN WANG AND JOE LIAO
April 6, 2018
This article is adapted from a submission for the 2017 Hong Kong Seek Road Dream City Urban Design Competition. The competition challenged participants to select a site of 100 hectares and come up with a plan that accommodates up to 100,000 residents. 100 Hub received First Prize as well as Public’s Favorite Prize by online voting. Elements of the original proposal have been revised and edited for this publication.
A city’s ability to respond to emerging challenges such as an aging population, rising cost of housing, changing patterns of work and lifestyle, and climate change is crucial to advancing its livability and competitiveness in the near future. This article takes Hong Kong as a case study, and advocates three main design proposals: intergenerational co-living, terraced housing, and agricultural technology. These suggestions aim to advance Hong Kong as a high-density and sustainable city in an increasingly urbanized world.
Hong Kong was ranked the world’s priciest home market for the seventh year in 2017. Apartments cost on average 18.1 times the median income, surpassing the cost to income ratio in Sydney, Vancouver, and San Francisco, cities that typify what has been called the affordability crisis today. Indeed, the high cost of housing in this Asian metropolis has emerged as one of the most urgent issues facing the city, with ramifications extending far beyond the realm of housing policy and into that of land use, economic opportunities, and social discontent.
At the same time, Hong Kong boasts more than just the world’s most expensive home; it is also home to people who live “the world’s longest lives.” This may be a cause of considerable pride, but a steadily declining birth rate clouds over the city’s future. According to government census, in the next three decades, one in three residents will qualify as elderly, legally defined as 65 years old or above, while those below age 14 will decrease to less than 10% of the total population. Soon enough, Hong Kong will reckon with the challenges of caring for an aging population.
Fig 1. Population distribution by age, Hong Kong (1960 – 2062). Data: World Bank and Hong Kong Census and Statistics Department
The issues of housing and an aging population may appear at first separate and unrelated, but a closer look soon reveals their mutual dependency. For one, housing needs to evolve as household composition changes. Increasingly, families have become more nucleated, with one-to-two-person households projected to represent nearly half of all households by 2024 (see fig. 2). Among them are a growing proportion of elders who live on their own, often with minimal built-in support. Even if elder care service is quickly expanded, housing design will need to adapt as well in order to ensure that those who live in care facilities feel safe and free.
To address the twofold challenges of demographic shifts and housing provision, our first proposal is to adopt intergenerational coliving at a community level. In this arrangement, older and younger adults live together in housing units designed specifically to accommodate the needs of these two age groups. Design features, on the hardware side, can include wider hallways with handrails to ensure safe and easy access, good sound proofing to reduce noise disruptions, and spaces with various level of openness to balance social interaction and privacy; on the software side, to increase resident compatibility, monitor level of physical activity to predict healthiness of elders, and set up a system of shared responsibility to enhance community trust. Compared to existing options such as micro-units on one hand and senior homes on the other, intergenerational coliving can deliver greater community support for elderly while helping to reduce the cost of housing for senior citizens and young adults alike.
Fig 2. Household size distribution in Hong Kong (2014 – 2024) and proposed distribution. Data: Hong Kong Housing Department
Given the complexity of the housing model, a public-private partnership is likely to have the greatest promise for success. A social enterprise would take charge of the management while the government provides policy incentives for the execution and project delivery such as land grant or access to healthcare and social service resources. From a land use perspective, the coliving model serves to optimize apartment sizes in relation to household composition. Assuming that it accounts for up to 20% of new housing construction, it can potentially reduce residential space need by up to 9%.
Terraced Housing Scheme
A new approach to land acquisition will also be necessary to fully tackle Hong Kong’s housing shortage. To this end, we utilized GIS (Geographic Information System) analysis to systematically and transparently conduct our land search. Taking into consideration current development plans, major infrastructural projects, and city topography as well as flood risks posed by climate change, we arrived at the northeastern side of Lantau Island, just south of the small town Mui Wo.
Figure 3. Terraced farms of Yunnan, China. Source: Wikipedia Commons.
Given the hilly landscape of the site, we proposed a housing type that takes inspiration from the terraced farm and village houses in Yunnan, China, and the Greek Cycladic houses. Low-rise houses of five to six stories stretch out along the contour lines of the hills and are fully connected horizontally. Every 100 meters, a communal core provides common activity spaces as well as vertical circulation to connect the terraces. The diminished building height increases the feasibility and efficiency of development on slopes by reducing the depth of building foundations.
Figure 4. Map of flood risks associated with rising sea-level.
Further reference to the terraced farms is evident in the utilization of rooftop space. The connection between the rooftop of one level and the ground floor of the level above allows two spaces to be designed collectively as pathways, green spaces, and/or communal farms. This integrated approach contrasts with the dominant high-rise development in Hong Kong in which ground spaces are often of low air and light quality while rooftop areas are practically unutilized. From an economic point of view, the loss of density from capped height is made up for in spread since roads and green spaces are overlaid on residential rooftops, which results in a level of density comparable to that of most existing high-rise housing.
Experientially, the terrace type poses minimal visual impact on both the landscape and the city. The stepped structure serves to avoid a common frustration of urban living in Hong Kong: the window-to-window view. From above, green roofs and community farms cover the buildings, visually and functionally integrating them into the natural landscape, as in the case of terraced farms in China and Southeast Asia, many of which have become popular tourist destinations. Since the housing follows topographic contours, horizontal access will be largely level, making it ideal for bike-sharing. In our proposal, bike stations are distributed on each terrace near the community core so that vertical and horizontal circulation is integrated. As in the case with traditional terraced farms, the stepped form makes for easy water capturing and reuse, thus reducing water consumption for the upkeep of the green spaces.
Though the proposal was originally conceived for a specific site, the terraced house typology may prove feasible for countless other areas with slopes of similar grade, curvatures and geological composition. This opens up a fair amount of possible lands for development across Hong Kong, at the same time alleviating the pressure for landfills which result in lands that are at the highest-risk of being compromised by climate change.
Figure 5. View from hiking trail above 100hub. The terraced housing formation blends into the natural landscape.
The third and final section of our proposal puts forth agriculture and technology as a high-yield area for economic development. Though agriculture rarely participates in city design today, recent development in fields such as landscape architecture have brought into focus the value of ecological design in urban areas. More specifically, a wide range of community-based agricultural projects have recently taken root in cities around the world, ranging from rooftop beekeeping to raising oysters in city waters. Technological developments such as better greenhouses and aquaponics are also beginning to render urban agriculture increasingly feasible, reliable, and likely profitable.
Figure 6. View on terrace level. Rooftops are connected with roads and used as community gardens and green spaces.
Since the economic boom in the 1980s, the importance of agriculture to Hong Kong’s economy has drastically declined. In 2014, it accounted for less than 0.1% of the city’s gross domestic output. As an economy, Hong Kong relies primarily on financial services, trading and logistics, tourism, and professional services, but an overreliance on these industries may prove imprudent in the long run as questions about the future of work begin to emerge. Agriculture, partly due to its diminished role today, holds considerable promise for future growth.
Economic opportunities aside, establishing a strong agricultural base will have multiple added benefits. From a security perspective, by increasing local production, this helps boost the self-sufficiency of Hong Kong, which currently imports about 90% of its food. It is also likely to boost public confidence in food safety, where reports of such concerns are frequent.
Figure 7. Evergreens Republic is Hong Kong’s largest aquaponics farm.
In many respects, the challenges facing Hong Kong are reflective of those confronting major cities elsewhere — aging populations, housing affordability, food security, and climate change. Though these proposals remain largely speculative at this stage, a number of recent case studies are beginning to reveal their viability. Should these innovations be adopted at the city level, they have the potential to transform Hong Kong into a model for high-density, resilient urban living in a world that will continue to urbanize in the coming decades.
 “Hong Kong the world’s priciest home market for the seventh year,” South China Morning Post, Jan 23, 2017. http://www.scmp.com/business/article/2064554/hong-kong-named-most-expensive-housing-market-world-seventh-straight-year
 “Hong Kong women and men enjoy world’s longest life expectancy due to low smoking rates, health experts claim,” South China Morning Post, July 28, 2016. http://www.scmp.com/news/hong-kong/health-environment/article/1995947/hong-kong-women-and-men-enjoy-worlds-longest-life
 “More elderly live alone and in care facilities,” South China Morning Post, Sept 01, 2009. http://www.scmp.com/article/691142/more-elderly-live-alone-and-care-facilities
 A recent report published by the Joint Center for Housing Studies suggests that among other considerations, accessibility and community are some of the pressing challenges facing elderly housing. See “Housing America’s Older Adults,” Joint Center for Housing Studies Harvard University, 2014. http://www.jchs.harvard.edu/sites/jchs.harvard.edu/files/jchs-housing_americas_older_adults_2014.pdf
 The larger the family unit size, the less per person area is required due to the increased sharing of space.
 According to the 2011 Census, Mui Wo has a population of 5,485.
 See, for example, “New York’s Big Climate Plan Really Does Include Oysters” CityLab, Dec 15, 2015. https://www.citylab.com/environment/2015/12/new-yorks-big-climate-plan-really-does-include-oysters/419847/
 “Pearl farming in Hong Kong: enthusiasts restock oyster beds in city waters to revive a 1,000-year-old industry,” South China Morning Post, Feb 15, 2018. http://www.scmp.com/magazines/post-magazine/long-reads/article/2132680/pearl-farming-hong-kong-enthusiasts-restock