Cities of the Future

Cities and villages across the globe are confronting growing challenges of supplying safe clean water and sanitation services to residents and industry and protecting urban ecology. Urban populations are expanding, climate change is beginning to create more erratic patterns of droughts and storms threatening coastal areas with more flooding, and per capita consumption and use of resources is on the rise. It has been realized by the scientific community, policy makers, and now by public that the current wasteful urban metabolism (Rees, 1996, 1997), including water/stormwater/wastewater management is not sustainable, overuses resources, requires a lot of energy, and emits excessive amounts of greenhouse gases (GHG).

There is a need to implement water conservation and change the current linear system of water management and the entire urban metabolism to a cyclic system that would not only save water and energy but also be attractive to developers and city planners and desired by public. This paradigm of urbanization is based on the premise that urban waters are the lifeline of cities and the focus of the movement towards more sustainable cities (Novotny and Brown, 2007). Cities of the Future (COTF) evolution is ranging from the microscale “green” buildings, subdivisions, or “ecoblock” to macroscale ecocities and ecologically reengineered urban watersheds, incorporating also transportation, and neighborhood urban living.

The new paradigm must include consideration of energy and green house gas emission reductions and treat stormwater and reclaimed used water as a resource to be reused rather than wasted, requiring costly disposal that can further damage the environment. Therefore, the COTFs will combine concepts of “smart/green” developments and the landscape with natural systems and controls of pollution and stormwater flows from the landscape. They will reuse highly treated effluents and urban stormwater for various purposes including landscape and agricultural irrigation, groundwater recharge to enhance groundwater resources and minimize subsidence of historic infrastructure; environmental flow enhancement of effluent-dominated and flow deprived streams; and  for nonpotable water supply. The organic content and energy in used water will be treated as a recoverable resource along with reclamation and reuse of urban stormwater. 

The drive to develop sustainable cities (COTF) has emerged because of the realization of anticipated consequences of business as usual progression of cities under the major stresses of (1) population increases and migration, (2) threats of adverse impacts of global climatic changes, and (3) increasing water shortages in many highly populated regions of the world. There is now an almost uniform agreement among professionals in many disciplines that the current infrastructure and urban planning paradigm that relies on fast surface underground conveyance of water and wastewater, regional water and wastewater management systems, energy overuse and use of other resource in the cities, have become impediments to achieving sustainable urban development and living, and addressing the impacts of global climatic change. 

Content Table

• Urban metabolism
• Cities of the Future - Ecocites
• One Planet Living (OPL) principles
• Ecocity/ecovillage
• References
• Related Articles
• Links

Urban metabolism

Sustainability of the cities, pollution, and social qualities and other attributes and amenities are related to “urban metabolism” (Kennedy, Cuddihi, and Engel-Yan, 2007). Cities and their interconnected surroundings are complex systems consisting of nonliving infrastructure, machinery, roads and ecosystems with living organisms. Humans are a part of the ecosystem. The urban system receives inputs which are accumulated and growing, cycled, attenuated and transformed within the system and produces outputs (Figure 1). The urban metabolism can be defined as the “sum of the technical and socio – economic processes that occur within the cities, resulting in growth, production of energy, and elimination of waste (Kennedy et al., 2007). The balance or imbalance between the inputs, accumulation and growth, and waste resulting in emissions of undesirable pollutants determine the sustainability or un-sustainability of the city.

Generally, the inputs can be categorized into five groups

Materials (raw materials for buildings and production of goods and services within the city)   

Food (homegrown and imported)

Water (potable and nonpotable from the grid, harvested rainwater)

Energy (coal, natural gas, gasoline, electricity from renewable and fossil fuel sources)

Chemicals (industrial fertilizers, pesticides, road and highway deicing chemicals, pharmaceutical products and other drugs, household and commercial cleaners and solvents)

If new cities were continuing to be built and existing cities to operate in the current linear mode, the demand on resources – the ecological water footprints- would be three times more than the total available resources on earth (Rees, 1996, 1997; Daigger, 2009). Furthermore, the GHG emissions would dramatically increase over the current already unsustainable levels which would lead to social conflicts and tensions. The solutions are:

1) Conservation of input resources in the cities of the developing world which overuse.

2)  A switch from the linear to some form of circular (hybrid or almost fully closed) metabolism of inputs in the city resulting in the  reduction of waste and no pollution

3) Adaptation of circular metabolism in all new and retrofitted older communities.

Cities of the Future - Ecocites

The new paradigm of sustainable future communities introduced at the Wingspread Workshop (Novotny and Brown, 2007) offers a promise of adequate amounts of clean water for all beneficial uses. The most obvious differences between the current linear and unsustainable water/stormwater/used water and energy cities and the cities of the future are given in Table 1. Summarizing the discussions at the Wingspread Workshop and criteria by which the concepts and performance of the new sustainable urban water management will be judged include:

• replacing the linear flow through systems by an integration of water conservation, stormwater management and wastewater disposal into a one system managed on a principle of a hybrid (partially closed) of fully closed hydrologic balance concept (Heaney et  al., 2000);

• considering designs that reduce risks of failure and catastrophes due to the effects of extreme events and are adaptable to future anticipated increases of temperature and associated weather and sea level changes (IPCC, 2002);

• incorporating LEED (USGBC, 2005) certified green buildings that will reduce water use by water conservation, reduce storm runoff with best management practices (BMP’s), including green roofs, rain gardens and infiltration;

Table 1    Comparison of Traditional and Cities of the Future (Fifth Paradigm) Concepts

Adapted from Valerie Nelson, unpublished document

• incorporating heat energy and cooling water recovery from sewage in the cluster water reclamation and energy recovery facilities;

• implementing new innovative and integrated less energy demanding infrastructure for reclamation and reuse of highly treated effluents and urban stormwater for various purposes including landscape irrigation and aquifer replenishment (Hill, 2007; Ahern 2007); LEED criteria; minimization or even elimination of long distance subsurface transfers of stormwater and wastewater and their mixtures (Heaney et al., 2000);

• energy recovery from used water; environmental flow enhancement of effluent-dominated and flow-deprived streams; and ultimately a source for safe water supply;

• strive for net zero GHG footprint by incorporating renewable energy sources into the system of the water-energy nexus;

• implementing surface stormwater drainage and hydrologically and ecologically functioning landscape, making the combined structural and natural drainage infrastructure and the landscape far more resilient to the extreme meteorological events than the current underground infrastructure. The landscape design will emphasize interconnected ecotones containing ecologically with a viable interconnected surface water systems. Surface stormwater drainage is also less costly than subsurface systems and enhances aesthetic and recreational amenities of the area (Hill, 2007;  Ahern, 2007);

• considering pollution loading capacity of the receiving waters as the limit for residual pollution loads (Rees, 1996; Novotny, 2003) as also defined in the Total Maximum Daily Load (TMDL) guidelines and documents (US EPA, 2007), and strive for zero pollution load systems (Asano et l., 2007);

• adopting and developing new green urban designs through new or reengineered resilient drainage infrastructure and retrofitted old underground systems interlinked with the daylighted or existing surface streams (Novotny, Ahern, and Brown, 2010);

• reclaiming and restoring floodplains as ecotones buffering the diffuse (nonpoint)  pollution loads from the surrounding human habitats and incorporating best management practices that increase attenuation of pollution such as ponds and wetlands;

• connecting green cities, their transportation needs and infrastructure with drainage and receiving waters that would be ecologically based, protecting the aquatic life, provide recreation and by doing so be acceptable to and desired by the public;

• decentralization of water conservation, stormwater management and used water treatment to minimize or eliminate long distance transfer, enable water reclamation near the use and energy recovery (Heaney et al., 2000);

• developing surface and underground drainage infrastructure and landscape that will:
  1. store and convey water for reuse and providing ecological flow to urban flow deprived rivers, and safe downstream uses;
  2. treat and reclaim polluted flows; and
  3. integrate the urban hydrologic cycle with multiple urban uses and functions to make it more sustainable.

One Planet Living (OPL) principles

The World Wild Life Fund (WWF, 2008) and the charity, Bioregional,  have developed and are promoting the principles that include social and technological metrics under the name of One Planet. Some ecocity developments are now aiming at OPL certification (e.g., Masdar, Sonoma Valley-see next section) to showcase  their  ecocity/ecovillage status. These criteria are far more broad and stringent than LEED criteria. OPL criteria are as follows:

·         zero carbon emissions with 100% of the energy coming from renewable resources;

·         zero solid waste with the diversion of 99% of the solid waste from landfills;

·         sustainable transportation with zero carbon emission coming from transportation inside of the city;

·         local and sustainable materials used throughout the construction;

·         sustainable foods with retail outlets providing organic and or fair trade products;

·         sustainable water with a 50% reduction in water use from the national average;

·         Natural habitat and wildlife protection and preservation;

·         Preservation of local culture and heritage with architecture to integrate local values;

·         equity and fair trade with wages and working conditions following the international labor standards; and

·         health and happiness with facilities and events for every demographic group.

Ecocity/ecovillage

The notion of the Cities of the Future is in many aspects synonymous to the earlier defined “Ecocity” presented in the Box. COTFs represent a major paradigm shift in the way new cities will be built or older ones retrofitted to achieve a change from the current unsustainable status to sustainability. Rigorous analysis of the performance of current and alternative urban systems is required to give weight to the paradigm shift toward more sustainable urban designs.  An ecocity is a city or a part thereof that balances social, economic and environmental factors (triple bottom line) to achieve sustainable development.

Definition

An ecocity is a city or a part thereof that balances social, economic and environmental factors (triple bottom line) to achieve sustainable development. It is a city designed with consideration of environmental impact, inhabited by people dedicated to minimization of required inputs of energy, water and food, and waste output of heat, air pollution - CO₂, methane, and water pollution. Ideally, a sustainable city powers itself with renewable sources of energy, creates the smallest possible ecological footprint, and produces the lowest quantity of pollution possible. It also efficiently uses land and recycles or converts waste to energy. If such practices are adapted, overall contribution of the city to climate change will be minimal and below the resiliency threshold. Urban (green) infrastructure; resilient and hydrologically and ecologically functioning landscape and water resources will constitute one system.

Adapted from Register (1987) and Novotny et al.(2010)

Table 2 shows the degree of decentralization and cluster management of various components of the future hydrologically and ecologically functioning ecocities. COTF concept is not a utopian vision but a necessity because the current unbalanced linear water/stormwater/wastewater management is not sustainable, requires a lot of energy, and emits excessive amounts of greenhouse gases (GHG). In some developed countries water infrastructure is crumbling and, in developing countries, it either does not exist or is not functioning. There is a need to implement water conservation and change the linear system of water management and the entire urban metabolism to a cyclic or hybrid system that would not only save water and energy but also be profitable to developers and city planners and desired by public. The “Cities and Villages of the Future – the Ecocities” are now emerging from the laboratories and design studios of architects and water consultancies into reality in some countries, including Australia, Canada (Dockside Green in Victoria BC), China (Tianjin, Caofeidian, parts of Beijing, Harbin, Shenyang, Beijing, Chengdu, cluster of cities in the Pearl River Delta, etc.), Germany, Singapore, Sweden (Hammarby Sjöstad, Malmö), United Kingdom (2012 Olympic Sites ), Portugal, Kenya, Brazil, Democratic Korea, United Arab Emirates (Masdar). Figure 2 is a photograph of one of the first communities built with the COTF concepts – the Hammarby Sjöstad, a part of Stockholm (Sweden). 

Table 2   Centralized and decentralized components of the future ecocities (Adapted from Daigger, 2009)

Figure 2

Hammarby Sjöstad in Stockholm is the first sustainable ecocity in the developed world.

Photo courtesy Malena Karlsson, GlashusEtt, Stockhom, Sweden.   

References

This article has been written by Vladimir Novotny.

For more information on the subject, see the recently published book: Cities of the Future, Towards integrated sustainable water and landscape management, edited by Vladimir Novotny and Paul Brown.

Ahern, J. (2007) Green infrastructure for cities: The spatial dimension, a chapter in Cities of the Future: Towards integrated sustainable water and landscape management (V. Novotny, and P. Brown, eds.), IWA Publishing, London, UK

Asano, T,  F.L. Burton, H.L. Leverenz, R. Tsuchihashi, and G. Tchobanoglous (2007) Water Reuse – Issues, Technologies, and Applications, Metcalf & Eddy/WECOM, McGraw Hill, New York

Daigger, G. (2009) Evolving urban water and residuals management paradigms: Water reclamation and reuse, decentralization, resource recovery, Water Environment Research 81(8):809-823

Heaney, J.P, L.Wright, and D. Sample (2000) Sustainable urban water management, Chapter 3 in Innovative Urban Wet-Weather Flow Management Systems (R.. Field, J. P. Heaney, and R.Pitt, eds.) TECHNOMIC Publ. Comp., Lancaster. PA

Hill, K. (2007) Urban ecological design and urban ecology: an assessment of the state of current knowledge and a suggested research agenda, in Cities of the Future: Towards integrated sustainable water and landscape management (V. Novotny and P. Brown, eds), IWA Publishing, London, UK

IPCC (2007). Summary for Policy Makers, Climate Change 2007: The Physical Scientific Basis, Fourth Assessment Report, Intergovernmental Panel on Climatic Change, Working Group (WG 1),Geneva.

Kennedy, C., J. Cuddihy, and J. Engel – Yan (2007) The changing metabolism of cities, Journal of Industrial Ecology, 11(2):43-59

Novotny, V. (2003) WATER QUALITY: Diffuse Pollution and Watershed Management, J. Wiley, Hobokan, New Jersey

Novotny, V. and P. Brown (2007) Cities of the Future-Towards  Integrated Sustainable Water, Landscape and Infrastructure Management” IWA Publishing Co., London

Novotny, V. J.F. Ahern, and P.R. Brown (2010) Water-centric Sustainable Communities: Planning, Building and Retrofitting Future Urban Environments, J.Wiley & Sons, Hoboken, NJ (in press)

Rees, W. E. (1996) Revisiting carrying capacity: Area based indicators of sustainability. Popul. Environ. 17:195-215

Rees, W. E. (1997) Urban ecosystems: the human dimension,, Urban Ecosystems 1:63-75

Register, R.  (1987) Ecocity Berkeley: building cities for a healthy future, North Atlantic Books. ISBN 1556430094

US Environmental Protection Agency (2007) Total Maximum Daily Loads with Stormwater Sources: A Summary of 17 TMDLs, EPA 841-R-07-002, Office of Wetlands, Oceans and Watersheds, Washington, DC,(www.epa.gov/owow/tmdl/techsupp.html)

USGBC (2007) LEED for Neighborhood Development Rating System, Pilot Version, US Green Building Council, Washington, DC. , http://www.usgbc.org

WWF (2008) One planet living, World Wildlife Fund, http://www.oneplanetliving.org/index.htm 

Related Articles

Cities of the Future Resources
Sustainable Water Infrastructure for Villages and Cities of the Future

Links

WWF

Bioregional Charity