Water supply system and historical development

A water supply system is the complete set of works (source, intake, treatment, transmission, storage and distribution) that collects water from a source and delivers it to consumers in adequate quantity, of adequate quality and at adequate pressure.

Historical development

• Ancient period: Early settlements grew along rivers, lakes and springs. People used hand-dug wells and carried water in pots. The Indus Valley civilisation (Mohenjo-daro, about 2500 BC) had wells and covered drains.
• Roman period: Aqueducts brought water by gravity over long distances to cities; lead and masonry pipes, public baths and fountains were used (about 300 BC to 200 AD).
• Middle Ages: Water supply and sanitation declined in Europe, and outbreaks of disease were common.
• 17th to 18th century: Cast iron pipes and steam pumps came into use, and cities such as London and Paris built piped supplies.
• 19th century: Slow sand filtration was introduced (Paisley, Scotland, 1804; London, 1829). John Snow showed in 1854 that cholera spreads through water, and Pasteur and Koch established the germ theory. Rapid filtration began in the late 1800s and chlorination in the early 1900s.
• 20th century: Chemical coagulation, mechanical filters, ozone and UV treatment were developed, along with national and international (WHO) drinking water standards.
• Nepal: Ancient stone spouts (hiti or dhunge dhara) supplied water in the Kathmandu valley. Piped supply started in 1891 AD (1948 BS) under Bir Shumsher, with the Bir Dhara. Later the Nepal Water Supply Corporation (1990) and Kathmandu Upatyaka Khanepani Limited (2008) were formed. Rural schemes expanded under the Department of Water Supply and Sewerage and during the International Drinking Water Supply and Sanitation Decade (1981 to 1990).