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Water Demand Estimates

The document provides information on estimating water supply demand including the basic equation and factors to consider. It then gives two example calculations: 1) Estimating demand for a housing scheme with 225 homes, a mosque, and school totaling 507,131.25 liters per day. 2) Estimating annual demand for a "mukim" with 3,500 dwellings, 6 people per unit, and industrial and non-revenue water factored in, totaling 18.1 million liters per day.

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Kamarul Nizam
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2K views4 pages

Water Demand Estimates

The document provides information on estimating water supply demand including the basic equation and factors to consider. It then gives two example calculations: 1) Estimating demand for a housing scheme with 225 homes, a mosque, and school totaling 507,131.25 liters per day. 2) Estimating annual demand for a "mukim" with 3,500 dwellings, 6 people per unit, and industrial and non-revenue water factored in, totaling 18.1 million liters per day.

Uploaded by

Kamarul Nizam
Copyright
© Attribution Non-Commercial (BY-NC)
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as PPSX, PDF, TXT or read online on Scribd
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01/12/13

WATER SUPPLY DEMAND ESTIMATES


The basic equation for water supply demand estimation is given by Wdn = (Pn x q x F1 x F2) + NRW + Dn

where:
Wdn Pn q F1 = = = =

Water supply demand at the nth year end Population at the nth year end Per capita water supply demand Service Factor at nth year end (% of population covered by supply scheme) F2 = Design Factor NRW = Non Revenue Water Dn = Additional demand (eg. Industry, social, agriculture etc) Design Factor F2 is intended to compensate for water demand variations arising from seasonal changes, public activities, non-uniform industrial, commercial and agricultural activities. NRW is accounted through the water supply demand of a particular population group. click

01/12/13

Calculated example : Find the water supply demand for a housing scheme of 225 houses (7 person/unit) a mosque and a school with the following requirements; Water demand : i) people ii) mosque iii) school Design Factor Non-Revenue Water (NRW) = = = = = 145 litre/person/day (l/p/d) 2,500 litre/day (l/d) 5,000 litre/day 2.0 (peak factor) 15% click

Solution:
Daily water supply demand, Wdn = = (Pn x q x F1 x F2) + NRW + Dn Population NRW Industry etc

[ (225 x 7 x 145 ) + 2,500 + 5,000 ] x 2.0 + [ (225 x 7 x 145 ) + 2,500 + 5,000 ] x 15% +0 471,750 + 35,381.25 + 0 507,131.25 litre/day

= =

click

01/12/13

Calculated example : The following data is gathered for a mukim in the year 2005.
Dwellings Average occupancy Water consumption Industrial demand Design factor NRW = = = = = = 3,500 units 6 p/unit 275 l/p/d 1/3 of population demand 2.0 15 %

Estimate the water supply demand for that year with a coverage supply of 95% to the total population.

click

01/12/13

Data re-listed : Water usage Industrial demand Design factor NRW

= = = =

275 l/p/d 1/3 of total population 2.0 15 %

.... in the year 2005 where water supply coverage is 95% ... Daily demand, Population water usage Wdn = = = Industrial demand , Dn = = (Pn x q x F1 x F2) + NRW + Dn 21,000 x 275 x 0.95 x 2.0 10,972,500 l/d 1/3 x ( 21,000 x 275 x 2.0 ) 3,850,000 l/d
(calculated without coverage factor but with design factor)

NRW

=
=

15% x [ (21,000 x 275 )


Industry

population

+ 1/3 x ( 21,000 x 275 ) ]

1,155,000 l/d

Losses (calculated without design nor coverage factor)

Total Water Supply Demand

Thank you

= = =

10,972,500 + 3,850,000 + 1,155,000 15,977,500 l/d 18.1 x 10 6 l/d or 18.1 Ml/d

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