Urban Water Management
Sustainable management of urban water has been necessitated to ensure urban sustainability. Growing population and aging infrastructure are creating challenges for efficient water management in cities. Groundwater decline is major problem across the cities relying on groundwater as a source of drinking water. Higher rate of abstraction of groundwater than its replenishment causes water table to decline. UN statistics reveals two people being added to the urban population every second, and 27% of the urban population are lacking access to piped water at home.
Declining levels of groundwater have been assessed in cities such as Barcelona, Houston, Los Angeles, Mexico City, New York, Rome, many large cities in China, Libya, India and Pakistan and Middle East and Central Asian regions in a study using global hydro-logical model PCR-GLOBWB. Dhaka, capital city of Bangladesh, faces groundwater depletion problems as 84% of present municipal water comes from groundwater. Groundwater levels in 54 percent of the wells in India have been found to be decreasing and 16 percent are declining by more than one meter per year. India experienced 10-25 mm groundwater decline between 2002 and 2016 and 200,000 people are being severely affected by lack of access to safe drinking water.
A positive effect of urbanisation on groundwater includes increases in recharge by water-mains leakage, waste water seepage, storm-water soakways and excess garden irrigation. However, contamination from in-situ sanitation, sewer leakage, industrial chemical pollution and disposal of liquid effluents and solid wastes are pitfalls of urbanisation.
Management of water supply infrastructure is challenging and expensive. Water supply pipes are mostly underground and monitoring is arduous task. The leakage statistics of average UK home is 133 litres per day. Huge proportion of purified water could be lost because of aging and leaky pipes, broken water mains and faulty meters.
Increasing water demand, higher rate of water abstraction and rapid urbanisation might induce effects such as induced seepage of contaminated water, land subsidence and coastal saline intrusion. Government initiatives will be less effective if vacuum exists for responsibility and accountability of urban water management. Integrated approach with wider participation of stakeholders, public and private agencies will be more effective in managing urban water.