## Table 112

Average Daily Flow Rates (m3/hr) for the Months of June and July

Day Flow Rate

1 38.29

4 38.04

7 38.33

10 38.40

13 45.00

16 29.96

19 30.90

22 31.04

25 38.46

28 38.38

31 30.92

34 38.83

37 37.50

40 42.21

43 32.00

46 44.92

49 32.00

52 30.33

55 37.92

58 34.50

61 32.71

Day Flow Rate

June

2 30.92

5 31.21

8 30.92

11 38.83

14 37.50

17 42.75

20 45.00

23 44.92

26 30.92

29 30.54

July

32 45.20

35 30.92

38 38.29

41 34.13

44 37.38

47 44.56

50 36.79

53 38.83

56 38.00

59 43.67

Day Flow Rate

3 45.21

6 31.13

9 45.20

12 30.89

15 30.67

18 38.80

21 37.50

24 45.21

27 37.46

30 38.38

33 38.42

36 45.21

39 30.92

42 31.79

45 32.58

48 37.96

51 38.58

54 31.04

57 36.83

### 60 42.54

drawing small rectangles; each of these rectangles has an area equal to the height multiplied by the time interval (equals 2). The areas of each of these rectangles are then added. This summation divided by 24 represents the average daily flow rate for this first day of June, 38.29 m /h. This procedure is repeated for each of the days up to the full 61 days duration of the study. The results are given in Table 1.12.

The next step is to arrange the data in either the ascending or descending order. Choosing the descending order, Table 1.13 is produced. Reading at the 0.5 probability, the mean is 37.92 m3/h. Thus, the average daily flow rate is 37.92 m3/h. If the 0.50 probability had not been available from the table, then the mean would have to be interpolated.

### 1.7.2 Peak Hourly Flow Rate

The peak hourly flow rate will now be derived. Remember that maximum values correspond to a probability of zero. Therefore, to obtain the peak hourly flow rate, read or extrapolate the flow rate corresponding to zero in the probability distribution obtained from an array arranged in descending order. 