It is the annual average amount of daily water required by one person and includes the domestic use, industrial use and commercial use, public use, waste thefts etc.<\/p>\n
It may be, therefore expressed as Per Capita Demand(q) in litres per day per person …(i)<\/p>\n
= Total yearly water requirement of the city in litres (i.e V) \/ 365 \u00d7 Design Population<\/p>\n
Thus, total yearly requirement of city can be estimated using eq. (i) provided that per capita demand is already known or assumed.<\/p>\n
For an average Indian city, as per recommendation of I.S. code, the per capita demand(q) may be taken as given in table.<\/p>\n
| Break up for per capita demand (q) for an average Indian City<\/th>\n<\/tr>\n | |
|---|---|
| Use<\/th>\n | Demand in \/pcd<\/th>\n<\/tr>\n |
| \n (i) Domestic Use<\/p>\n (ii) Industrial Use<\/p>\n (iii) Commercial Use<\/p>\n (iv) Civic or Public Use<\/p>\n (v) Waste and thefts, etc.<\/p>\n (vi) Fire demand<\/p>\n<\/td>\n | \n 200 (59.7% or 60%)<\/p>\n 50<\/p>\n 20<\/p>\n 10<\/p>\n 55<\/p>\n < 1<\/p>\n<\/td>\n<\/tr>\n |
| \n Total = 335<\/p>\n \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 = Per Capita Demand (q)<\/p>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n DESIGN PERIOD OF WATER SUPPLY UNIT<\/h2>\nA water supply scheme includes huge and costly structures (such as dams, reservoirs, treatment works, penstock pipes, etc.) which cannot be replaced or increased in their capacities, easily and conveniently. For example, the water mains including the distributing pipes are laid underground, and cannot be replaced or added easily, without digging the roads or disrupting the traffic. In order to avoid these future complications of expansion, the various components of a water supply scheme are purposely made larger, so as to satisfy the community needs for a reasonable number of years to come. This future period or the number of years for which a provision is made in designing the capacities of the various components of the water supply scheme is known as design period. design period The design period should neither be too long nor should it be too short.<\/p>\n |