Test: Water Demand - Civil Engineering (CE) MCQ

Good Quality water, hotter climate and modern living, all these factors will increase the per capita water consumption.
However, metering system will reduce the consumption as people will be cautious while using the water as they need to pay for it.

Maximum daily demand
= 1.8 x Average daily demand Maximum hourly demand
= 1.5 x Maximum daily demand

Maximum hourly consumption of the maximum day i.e. peak demand

For general community purposes, the total draft is not taken as the sum of maximum hourly demand and fire demand, but is taken as the sum of maximum daily demand and fire demand, or the maximum hourly demand, whichever is more. The maximum daily demand (i.e. 1.8 times the average daily demand) when added to fire draft,for working out total draft, is known as coincident draft.

In geometric increase method compounding is done every decade unlike in arithmetic increase method. Thus geometrical increase method gives higher value than the arithmetic increase method.

Equation of logistic curve is given by,
In [(P_s - P)/(P_s - P₀)] = -kP_st
where,
P₀ = The population at the start pt. of the curve A
P_s = Saturation population
P = Population at any time t from the origin A
K = Constant

Break up of per capita demand (q) for an average Indian city

∴ Design growth rate,

In 2010 population will be,
P = 58000 + 6000 = 64000

The pipe mains carrying water from the source to the reservoir are designed for the maximum daily draft = 1.8 times the average daily draft.
However, pipes for distributing water to households etc. are designed for maximum hourly draft of the maximum day = 2.7 times the average daily draft.