With global demand for water projected to outstrip supply by 40% in 2030, cities around the world are facing a water-insecure future unless they balance rising demand with limited, and often variable, supplies.
Water security, according to the United Nations, is 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; ensuring protection against water-borne pollution and water-related disasters; and for preserving ecosystems in a climate of peace and political stability.
In other words, water security is the ability of a population to access good quality water of sufficient quantity necessary for sustaining livelihoods, human well-being and socio-economic development.
In the context of cities, urban water security is the ability of an urban population to safeguard sustainable access to adequate supplies of good quality water.
Challenges to urban water security
There are numerous climatic and non-climatic challenges to urban water security including:
- Variable precipitation levels and increased storm events: Storm events (flooding) wash pollutants from urban areas into surface water bodies, as well as contaminate ground water supplies: In the Danube region annual precipitation will probably remain constant, but seasonal changes are expected to occur, with a decrease in summer and an increase in winter
- Heat-island effects: Air temperatures in urban areas compared to surrounding rural areas are 3.5 to 4 degrees Celsius higher. The result is an increase in demand for water for cooling and drinking: In Vienna, the number of summer days that are 25° C or more is projected to increase by 30-50% over the period 2071 to 2100
- Heat waves and droughts: During heat waves and droughts, demand for water increases (drinking water and water for cooling)
- Land-use changes: Water quality is threatened by land-use changes that degrade ecosystems, as well as increased pollution. For instance, municipalities generate around 60% of the wastewater treated in the Danube River Basin, much of which is not significantly treated
- Inefficiency: Water is frequently wasted with leakages in the supply system, no water saving technologies installed, too much unnecessary irrigation, dripping taps etc. According to the European Commission, 20-40% of Europe’s available water is being wasted while a ‘business as usual’ scenario will see water consumption increasing by 16% by 2030
The costs of increasing water supply
Traditionally, cities facing increased demand for water, along with variable supply, have relied on large-scale, supply-side infrastructural projects such as dams and reservoirs to meet increased demand for water. This is termed ‘supply-side’ management. However, supply-side management is costly in economic, environmental and political terms. Economically, water has to be transported over long distances increasing the costs of transportation. Additionally, the water is often of inferior quality and so requires additional treatment for potable consumption, increasing energy as well as chemical costs in water treatment plants. Environmentally, large-scale diversion of water disrupts the health of waterways that support aquatic ecosystems. Politically, because the vast majority of water is transboundary, ‘importing’ water creates political tensions with other water users, irrespective of whether they are located in the same country or not.
Achieving urban water security through demand management
Urban water security – the ability of an urban population to safeguard sustainable access to adequate supplies of good quality water – can be increased through demand management, which involves the better use of existing water supplies before plans are made to further increase supply. In particular, demand management promotes water conservation Click & Tweet! , during times of both normal conditions and uncertainty, through changes in practices, cultures and people’s attitudes towards water resources. Overall demand management aims to:
- Reduce loss and misuse
- Optimize water use by ensuring reasonable allocation between various users while taking into account downstream users, both human and natural
- Facilitate major financial and infrastructural savings for cities
- Reduce stress on water resources by reducing unsustainable consumption levels.
Types of demand management instruments
There are two types of demand management instruments available to cities to achieve urban water security: economic and regulatory instruments and communication and information instruments.
Economic and regulatory demand management tool examples
Economic and regulatory instruments including the pricing of water to lower consumption levels; subsidies and rebates for the uptake of water-efficient technologies; retrofitting of new or existing developments with water meters and water efficient devices; enforcing reductions of unaccounted for water (UFW) and product labeling of household appliances’ water efficiency.
Case 1: Water and wastewater charges in Singapore
Singapore’s Public Utilities Board (PUB) charges a volumetric tariff for domestic (residential) and non-domestic (non-residential) water consumption. For domestic users there are two tiers – for consumption rates between 1 to 40 cubic meters per month the tariff is $1.17, which combined with the WCT of 30% results in a total of $1.52 per cubic meters of water consumed, while above 40 cubic meters the tariff is $1.40 with a WCT of 45% resulting in a total of $2.03 per cubic meters of water consumed. After the water is used, it goes through the network and is treated and so customers pay a Waterborne Fee (WBF) (volume-based used water fee) and a fixed Sanitary Appliance Fee (SAF) (fixed used water fee based on the number of sanitary appliances). These two fees are used to recover the costs of treating the used water. For non-domestic users, the water bill is based on a flat volumetric rate (no tiers) with the tariff set at $1.17 per cubic meter of water consumed plus the WCT (30%) leading to non-domestic users paying $1.52 per cubic meter of water. For used water, non-domestic users also pay the volume-based WBF and SAF.
Case 2: Water Corporation of Western Australia’s Water Efficiency Management Plan Program
The Water Efficiency Management Plan Program requires all businesses using more than 20,000 kL of water a year to complete a Water Efficiency Management Plan (WEMP) to help save water. The program involves businesses detailing water saving actions and initiatives and providing annual progress reports about their efforts. As part of the program a WEMP includes:
- Site water use history
- Water saving opportunities (including benchmark indicators and targets)
- Water saving action plan (including timeframes)
- Management and Water Corporation commitment
Once the WEMP is submitted and accepted the plan is valid for 5 years. However, if the business changes ownership or water use increases significantly a revised WEMP may need to be submitted.
Communication and information instruments
Communication and information instruments including public education on the need to conserve water including public events and social media campaigns that raise awareness on the need to use water wisely as well as school curriculum that raises awareness of the hydrological cycle at a young age.
Case 3: San Francisco’s racy water conservation messages
Over the past few summers, the San Francisco Public Utilities Commission (SFPUC) has implemented a head-turning water conservation strategy that involves using bold, risqué, multilingual water conservation advertisements to change the behavior of water users in the city. The SFPUC’s racy public awareness advertisements, featured in or on newspapers, bus shelters, buses and billboards, were designed to get the heart racing with creatively crafted messages that blare out for customers to ‘’Jiggle it’’ when looking for leaks, ‘’Make it a quickie’’ when having a shower, and ‘’Doing it’’ by replacing old toilets and getting paid for it.
Case 4: Dubai’s push to save water (and energy)
Over the summer period, the Dubai Electricity and Water Authority (DEWA) ran its ‘Lets make the summer green’ program to promote the rational use of water, as well as electricity, during the sweltering hot months. The program, launched via social media channels as well as other audiovisual media channels, provided customers with tips on how to fix water leaks, install drip irrigation systems as well as encourage the setting of AC systems to 24°C. In addition, DEWA’s Conservation Team organized lectures and field visits to government organizations and departments, private companies, malls and union centers to raise awareness on the importance of rational use of water and electricity.
Water utilities can implement a variety of demand management strategies to become water-secure including pricing water to encourage efficient use, encouraging large non-domestic users to develop water efficiency plans, running catchy ad campaigns and harnessing the power of social media.
*Robert C. Brears is the author of Urban Water Security (Wiley). Urban Water Security argues that, with climate change and rapid urbanization, cities need to transition from supply-side to demand-side management to achieve urban water security.