By 2030, 5 billion people will be living in urban areas with hundreds of millions living in one of the world’s 41 mega-cities, up from 28 today. At the same time, global demand for water is projected to outstrip supply by 40 percent. As such, cities around the world are at risk of water insecurity, the inability of a population to access good quality water of sufficient quantity necessary for sustaining livelihoods, human well-being and socio-economic development.
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. This is termed “supply-side” management. However, supply-side management is costly in economic, environmental and political terms.
- Economically, water must 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, regardless whether they are in the same country.
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.
Demand management promotes water conservation, during times of both normal conditions and uncertainty, through changes in practices, cultures and people’s attitudes towards water resources. Demand management aims to:
- Reduce loss and misuse.
- Optimize water use by ensuring reasonable allocation between various users while considering downstream users, both human and natural.
- Facilitate major financial and infrastructural savings for cities.
- Reduce stress on water resources by reducing unsustainable consumption levels.
Two types of demand management instruments are available to cities to achieve urban water security: economic and regulatory instruments; and communication and information instruments.
Economic and regulatory instruments
Economic and regulatory instruments include 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: Vancouver’s seasonal water rates
In Vancouver, the price of water increases by around 25 percent during the drier months, compared to the low-peak rate from November through May, to reflect the added cost of supplying water to the city. The summer surcharge enables the city to meet its Greenest City 2020 goal of reducing water consumption by 33 percent, which has two benefits for all Vancouver residents:
- It helps reduce the strain on the city’s existing water system, eliminating the need for costly system upgrades that could lead to higher utility rates.
- It helps the city live within its water means, ensuring all residents have access to abundant safe, clean water no matter how much the city grows.
Case 2: Western Australia’s Water Efficiency Management Plan Program
The Water Corporation of Western Australia’s 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 five years. However, if the business changes ownership or water use increases significantly, a revised WEMP may need to be submitted. (…)
Makalenin tam metinini https://www.greenbiz.com/article/how-cities-can-fight-global-water-insecurity adresinde okuyabilirsiniz.