1. Patterns of Water Demand
Lecture 2
Patterns of Water Demand

2. Patterns of Water Demand
The water consumption varies hourly, daily, monthly and seasonally. This variation is caused by peoples activities that differs from one hour to another during the day , and by climate conditions.
Demand Patterns are diagrams that show the variation of water consumption during a certain period of time. These diagrams are based on recordings for each type of water demand (Domestic, commercial, industrial … etc). Then the diagram is plotted between the time on the X axis and the ratio of the recorded flow to the average flow on the Y axis.
Demand patterns for domestic consumption are usually generated using metric readings and billing records.
For other types of demand studies are made to generate the demand patterns.

3. House information Al Naser St. Residential Area Beach Camp well (3)
Source of water
Mostly (13:00-16:00)
Duration of water supply
2 floors
House
Upper tanks
Water recording
2 cold + 1 hot
No. of tanks 6
Family member
2 College students, 2 school pupils
Working Father
Description
Tank perimeter (m)
Diameter (D) (m)
Area m2

4. Consumption Q (litter ) Hour 186 4-6 15 6-8 63 8-10 28 10-12 19 12-2 9
2-4 71 50
8--10
136
10--12
12--2 31
2--4

5. Cumulative Consumption
Hour
Q (litter )
4-6
186
6-8
201
8-10
264
10-12
292
12-2
311
2-4
320
329
400
8--10
450
10--12
586
12--2
649
2--4
680

6. Average consumption\ 2 hours =
Consumption = 680\6 = l\c\d
Average consumption\ 2 hours = =
Hour
Pattern Values
4--6
3.280
6--8
0.264
8--10
1.110
10--12
0.494
12--2
0.335
2--4
0.158
1.252
0.882
2.410
0.547

7. Factor
Time ( hr )

8. Annual consumption Month Q ( m3 ) January 56 February 51 March 45
April 40
May 39
June 49
July 54
August 53
September 46
October 33
November 37
December 50

9. Annual pattern Month Pattern Values January 1.215 February 1.106 March
0.976
April
0.868
May
0.846
June
1.063
July
1.171
August
1.150
September
0.998
October
0.716
November
0.803
December
1.085

10. Factor

11. فندق مصنع بلاط زراعي (طماطم) زراعي (فراولة) مدرسة (فترتين)
مدرسة (فترة واحدة)
مسجد
محطة وقود
التجاري
الساعة
0.83
0.14
0.05
0:00-1:00
0.69
0.21
1:00-2:00
0.55
0.6
2:00-3:00
0.49
2.08
0.28
0.53
3:00-4:00
0.31
0.74
4:00-5:00
0.9
0.89
0.25
1.27
5:00-6:00
1.25
1.07
3.73
5.19
1.32
4.28
0.3
1.69
6:00-7:00
1.11
1.71
7.06
5.02
2.43
2.12
2.11
7:00-8:00
1.59
2.98
8:00-9:00
0.42
1.93
4.86
2.57
2.64
9:00-10:00
2.14
1.48
2.4
0.7
3.16
10:00-11:00
1.37
2.23
1.05
2.32
11:00-12:00
1.04
3.21
3.01
2.74
4.47
1.68
1.58
12:00-13:00
2.79
4.39
2.47
0.71
2.39
13:00-14:00
1.53
1.06
0.86
2.81
14:00-15:00
1.66
1.16
0.68
0.84
15:00-16:00
1.39
3.81
4.24
0.79
0.34
3.22
1.12
0.63
16:00-17:00
0.64
7.08
17:00-18:00
1.46
4.36
0.32
18:00-19:00
3.57
19:00-20:00
1.19
20:00-21:00
3.69
21:00-22:00
0.97
0.11
22:00-23:00
23:00-24:00

12. Example ( 1 )
A water supply company delivered an average annual quantity of 10,000,000 m³.On the maximum consumption day, the registered delivery was as follows :
Determine :
The daily pattern for the water delivery of that area.
The maximum seasonal variation factor for that day.
Hour 1 2 3 4 5 6 7 8 9 10 11 12
Q (m³/h)
989
945
902
727
844
1164
1571
1600
1775
1964
2066
2110 13 14 15 16 17 18 19 20 21 22 23 24
1600
1309
1091
945
1062
1455
1745
2139
2110
2037
1746
1018

13. Solution :
Find the average daily consumption = ∑ Q / 24 = m³/hr
For each hour, the pattern factor = Q / Qavg
Hour 1 2 3 4 5 6 7 8 9 10 11 12
Q (m³/h)
989
945
902
727
844
1164
1571
1600
1775
1964
2066
2110
Factor
0.68
0.65
0.62
0.5
0.58
0.8
1.08
1.1
1.22
1.35
1.42
1.45 13 14 15 16 17 18 19 20 21 22 23 24
1600
1309
1091
945
1062
1455
1745
2139
2110
2037
1746
1018
1.1
0.9
0.75
0.65
0.73
1.0
1.2
1.47
1.45
1.4
0.7

14. The seasonal variation factor = 1454.75/1141.55 = 1.274.
Time ( hr )
The average consumption, based on the annual figure = 10,000,000/365/24 = m³/h.
The seasonal variation factor = / =

15. Example ( 2 )
A water supply company delivers an annual volume of 13,350,000 m³. The maximum daily demand of 42,420 m³ was observed on 26 July. The minimum, observed on 30 January, was 27,360 m³. The following delivery was registered on 11 March:
Determine:
Delivery on an average consumption day and the range of seasonal peak factors.
The Final peak factor diagram.

16. Solution : Maximum seasonal Peak Factor =
Delivery on an average consumption day =
Minimum seasonal Peak Factor =
Maximum seasonal Peak Factor =
Range of seasonal peak factors 0.75 – 1.16
To generate the peak factor diagram : Q avg = 1435 m³/hr , Ps = 1.16
/day
Hour 1 2 3 4 5 6 7 8 9 10 11 12
Factor
0.35
0.454
0.52
0.675
1.172
1.328
1.5
1.553
1.564
1.525
1.391
1.383 13 14 15 16 17 18 19 20 21 22 23 24
1.32
1.338
1.446
1.555
1.686
1.661
1.571
1.174
0.984
0.657
0.546
0.486

17. Generate the final demand pattern for 24 hrs.
Example ( 3 )
A Family of 7 members has the following Daily Consumption :
Generate the final demand pattern for 24 hrs.
Hour 1 2 3 4 5 6 7 8 9 10 11
Q (l/h) 25 15 34 14 70 53 12 13 14 15 16 17 18 19 20 21 22 23 47 67 95
103 57 34 38 25
And the following Annual Consumption :
Month 1 2 3 4 5 6 7 8 9 10 11 12
Q (m³/d)
19.7
18.6
21.5
23.4
26.9
35.7
42.4
45.9
37.5
32.3
25.4
20.1

18. Solution :
Calculate the maximum monthly factor from the monthly pattern. The average monthly consumption = m³/d.
So the monthly peak factor = 1.58
Generate the pattern for daily consumption :
Qavg= m3/h
Month 1 2 3 4 5 6 7 8 9 10 11 12
Q (m³/d)
19.7
18.6
21.5
23.4
26.9
35.7
42.4
45.9
37.5
32.3
25.4
20.1
Factor
0.68
0.64
0.74
0.80
0.92
1.23
1.46
1.58
1.29
1.11
0.87
0.69
Hour 1 2 3 4 5 6 7 8 9 10 11
Q (l/h) 25 15
6.5 34 14 70 53
Factor
1.15
0.69
0.37
0.30
0.23
0.51
1.57
0.65
3.23
2.45 12 13 14 15 16 17 18 19 20 21 22 23 47 67 95
103 57 34 38 25
2.17
3.09
4.39
4.76
2.63
1.57
1.76
1.15
1.06
0.88
0.69

19. Example ( 4 )
For a given junction serves different average consumptions (Qave-2h) and patterns.
Calculate the total average consumption (Residential, Commercial & Agriculture) and combined pattern for this junction.
Time (hour)
0-2
2-4
4-6
6-8
8-10
10-12
12-14
14-16
16-18
18-20
20-22
22-24
Residential
(Qav=15 m3/2h)
0.5
0.3 2
1.5
1.1 1
1.2
0.8
Commercial
(Qav=3 m3/2h)
1.7
2.5 3
Agriculture
(Qav=10 m3/2h)
2.4
2.6

20. Equivalent Pattern Factor
Time (hour)
0-2
2-4
4-6
6-8
8-10
10-12
12-14
14-16
16-18
18-20
20-22
22-24
Qav
Residential
0.5
0.3 2
1.5
1.1 1
1.2
0.8
(Qav=15 m3/2h)
7.5
4.5 30
22.5
16.5 15 18 12
16.25
Commercial
1.7
2.5 3
(Qav=3 m3/2h)
2.4
5.1 9
3.6
Agriculture
2.6
(Qav=10 m3/2h) 10 24 26 20
Total Qav
29.25
The Total average consumption = m³/2 hr
Time (hour)
0-2
2-4
4-6
6-8
8-10
10-12
12-14
14-16
16-18
18-20
20-22
22-24
Residential
7.5
4.5 30
22.5
16.5 15 18 12
Commercial
2.4
5.1 9
3.6
1.5
Agriculture 10 24 26 20
Total Q
42.4
57.6 48 47
41.6
Equivalent Pattern Factor
0.256
0.154
1.450
1.969
1.641
0.821
1.607
1.422
0.564
0.410

21. Homework # 1
For Example ( 1 ), if an average leakage of 20 % is assumed. Find the daily pattern for the water consumption of that area.

22. Questions