The Asia-Pacific region is one of the most rapidly urbanising regions in the world. Currently, seven of the world's mega-cities (cities with populations of 10 million or more) are located in Asia-Pacific. However, by 2025 there will be 21 mega-cities in the region. With three out of four Asia-Pacific countries already experiencing water scarcity, urban centers in the region will likely face further water insecurity as a result of climate change and the various impacts of urbanization.
Temporary ordinances used in times of scarcity (e.g.bans on filling swimming pools). Photo: watermarkherveybay.com.au
Traditionally, urban water managers facing increased demand alongside varying levels of supplies have relied on large-scale, supply-side infrastructural projects, such as dams and reservoirs, to meet increased demands for water; however, these projects are economically unfeasible and environmentally unsafe. Environmental costs include disruptions of waterways that support aquatic ecosystems, while economic costs stem primarily from a reliance on more distant water supplies. Distant was supplies are often of inferior quality, which not only increases the costs of transportation, but also the cost of treatment; furthermore, the vast majority of water resources in Asia-Pacific are transboundary and supply-side projects can create political tensions due to intra- and inter-state administrative and political boundaries.
"Urban centers in the region will likely face further water insecurity as a result of climate change and the impacts of urbanization."
Challenges to urban water security in Asia-Pacific
Water security is defined as the following: 1) the capacity of a population to safeguard sustainable access to adequate quantities of acceptable quality water for sustaining livelihoods, human well-being, and socio-economic development, 2) ensuring protection against water-borne pollution and water-related disasters, 3) and for preserving ecosystems in a climate of peace and political stability. In other words, water insecurity is when a population does not have nearby access quality water to be used on sustaining livelihoods, human well-being and socio-economic development.
In the Asia-Pacific region, cities are at risk of water insecurity as a result of climate change and the various impacts of urbanisation. The Asia-Pacific region suffers disproportionately from natural disasters; for example, 90% of the population affected by natural disasters between 2001 and 2010 reside in the Asia-Pacific region. Water insecurity alongside the effects of climate change is likely to enhance the negative impact on these vulnerable populations. In the Asia-Pacific region, water security may decrease with the greater frequency and magnitude of floods and droughts. In particular, flooding affects the availability of quality water through the contamination of surface and groundwater supplies, while droughts affect the quantity of water and increases the demand of potable water. Climate change is projected to affect urban water security in the following ways:
- Precipitation and storm events: Storm events (flooding) wash pollutants from urban areas into surface water bodies, as well as contaminate ground water supplies.
- Heat-island effects: Air temperatures in urban areas compared to surrounding rural areas are elevated 3.5°C to 4°C higher; this situation increases the demand for potable water.
- Heat waves and droughts: During heat waves and droughts, demand for water increases (potable water and water for cooling).
- Sea-level rise and coastal flooding: Globally, cities are mainly concentrated among coastal zones. This situation leaves a significant portion of the world’s urban population exposed to the risk of sea-level rise and intensified storm-surges, which contaminate groundwater supplies and damage water infrastructure.
With urban populations in Asia-Pacific growing at 2.3% per annum, this region continues to be one of the most rapidly urbanising regions in the world and most vulnerable. Currently, there are 10 mega-cities in the region, but the number of mega-cities will increase to 15 by 2025. These cities will have an even more significant level of demand for water resources. In addition, water quality is threatened by land-use changes that degrade ecosystems as well as increased pollution. Patterns of urbanisation are projected to impact water security in a number of ways:
- Increase in population: Rapid population growth has increased domestic and non-domestic demands for water, frequently contributing to the over-exploitation of water resources. This results in excessive withdrawals and water scarcity.
- Land-use change: Urbanization (urban sprawl or encroachment into river basin catchment areas) lowers the availability of good quality water of sufficient quantity through direct and indirect pollution. Pollution can include, but not be limited to industrial or domestic wastewater and inorganic or organic pathogens.
- Degradation of ecosystems: Over-exploitation of ground and surface water degrades ecosystems and their services (e.g. reduced ability to purify water).
- Competition: Over-exploitation can lead to inter-sectoral, inter-regional, and possibly international competition over scarce water resources.
For all of these reasons, the Asia-Pacific reason will be characterised by growing water scarcity over the coming decades; ultimately, policymakers will need to address these challenges and provide appropriate use of demand management techniques.
Demand management to achieve urban water security
Demand management is the process by which improved provisions of existing water supplies are developed. In particular, demand management promotes water conservation during times of both normal and atypical conditions, through changes in practices, culture, and people’s attitudes towards water resources. Demand management involves communicating ideas, norms and innovating methods for water conservation across individuals and society; the purpose of demand management is to positively adapt society to reduce water consumption patterns and achieve water security.
Urban water managers use two types of demand management instruments to achieve urban water security: communication and information instruments and regulatory instruments.
Communication and information instruments
Communication and information instruments encourage a water-orientated society. In particular, communication and information tools aim to change behaviour through public awareness campaigns around the need to conserve scarce water resources.
Public education: Urban water managers use a variety of strategies, including informative educational sessions and supplemental information on water conservation to increase young people’s knowledge of the water cycle and encourage the sustainable use of scarce water resources. Meanwhile, water managers may also use public education to persuade individuals and communities to conserve water resources by increasing their knowledge and awareness of environmental problems associated with water scarcity.
Competition between users: Urban water managers can also increase participation rates in water conservation programmes by promoting competition among individuals and communities to achieve specific water consumption targets. Examples of competitions include eliciting commitments to water savings targets and promoting competition through a water utility bill. The water bill can also be used as a tool for competition between water users; for example, the water bills can compare a household’s water consumption to the average household in the neighbourhood, city, province or state.
Regulatory instruments are frequently used in concordance with water management standards and involve setting allocation and water-use limits. In addition, regulatory instruments are used to provide incentives for all water users to conserve water and use it efficiently.
Conservation awareness messages include taking shorter showers. Photo: Hgtv.com
- Conservation ordinances: Temporary urban water conservation ordinance and regulations restrict certain types of water use during specified times and/or restrict the level of water use to a specified amount. Meanwhile, permanent urban water conservation ordinance and regulations include amendments to building codes or requiring the installation of water meters and water-saving devices (e.g. low-flow toilets, showerheads, and faucets in all newly constructed or renovated homes and offices).
- Water pricing: Water managers can use a variety of different price structures, all of which send different conservation signals to individuals and communities: A flat rate for water usage regardless of the volume used, a volumetric rate based on the volume used at a constant rate (e.g. $1 per cubic meter of water used), an increasing block tariff rate containing different prices for two or more pre-specified quantities (blocks) of water with the price increasing with each successive block, and a two-part tariff system involving a fixed and a variable component.
- Subsidies and rebates: Economic instruments such as subsidies, incentives, or rebates may be used to modify an individual’s behaviour in a predictable, cost-effective way (e.g. reducing water consumption by providing subsidies for advanced water-efficient toilets).
- Product labelling and retrofit programmes: The labelling of household appliances according to the degree of water efficiency is important in reducing household water consumption by eliminating unsustainable products from the market. Retrofit programs use replacement devices to physically reduce water use in homes and offices. The most common type is toilet retrofits and aptly, older toilets replaced with newer low-/dual-flush toilets.
"Climate change and rapid urbanization are threatening urban water security."
Climate change and rapid urbanization are threatening urban water security in Asia-Pacific. This situation results in poor access to quality water. To achieve water security, urban water managers in the region can use demand management instruments to change people’s culture, attitudes, and practices regarding water resources and reduce consumption patterns. Specifically, communication and information instruments may be used to raise public awareness on the need to conserve threatened water resources, while regulatory instruments can be used to physically reduce water consumption levels through incentives.