Question

How the american cities meet water requirement of large population?

Answer 1

Water and Cities
Facts and Figures
Water and urban growth by numbers
Coping with the growing needs of water and sanitation services within cities is one of the most pressing issues of
this century. Sustainable, efficient and equitable urban water management has never been as important as in
today’s world.
• Half of humanity now lives in cities and, within two decades,
nearly 60% of the world’s population -5 billion people- will be
urban dwellers.
• Urban growth is most rapid in the developing world, where
cities gain an average of 5 million residents every month.
• The exploding urban population growth creates
unprecedented challenges, among which provision for water
and sanitation have been the most pressing and painfully felt
when lacking.
• The relationship between water and cities is crucial. Cities
require a very large input of freshwater and in turn have a
huge impact on freshwater systems.
• Cities cannot be sustainable without ensuring reliable access
to safe drinking water and adequate sanitation.
Every second, the urban population grows by 2 people.
95% of the urban expansion in the next decades will take place in the developing world.
In Africa and Asia, the urban population is expected to double between 2000 and 2030.
Between 1998 and 2008, 1052 million urban dwellers gained access to improved drinking water
and 813 million to improved sanitation. However, the urban population in that period grew by
1089 million people and thus undermined the progress.
One out of four city residents worldwide, 789 million in total, lives without access to improved
sanitation facilities.
497 million people in cities rely on shared sanitation. In 1990, this number was 249 million.
27% of the urban dwellers in the developing world do not have access to piped water at home.
UN-Water Decade Programme on Advocacy and Communication (UNW-DPAC) 1

Answer 2

The water in the supply network which is linked with the city are maintained at positive pressure to ensure that water reaches all parts of the network bumy constitution of it at a height that a sufficient flow is available at every take off point and to ensure that untreated water in the ground cannot enter the network. The water is typically pressurised by pumps that pump water into storage tanks constructed at the highest local point in the network in the city where the plant is developed.