The authors of the D.V.C. Data Book point out that ‘curves establishing relations between
flood storage versus damage in the lower valley have not been worked out after a
carefully planned survey of the affected regions after the occurrence of floods’, and that,
in consequence, the benefits of the moderation of floods achieved by the use of the
D.V.C. dams have not yet been assessed on a scientific basis. An approximate appraisal
of the flood-control benefits of D.V.C. is attempted in the Data Book as follows.
Firstly, the moderation of floods by the D.V.C. reservoir system since it started operating
in 1958 is described. This is shown here in Table 5
Table 5 Actual Moderation of Damodar Floods, 1958- 63
Date Peak flow (without dams)
In thousand cusecs*
Moderate flow at dams in
thousand cusecs*
23 - 24 July 1958 228 30
12 - 13 Aug 1958 126 32
16 - 17 Sept 1958 555 175
11 July 1959 134 71
21 - 22 July 1959 137 90
10 Sept 1959 137 101
13 Sept 1959 137 56
1 - 2 Oct 1959 623 288
25 - 26 Aug 1960 119 72
30 Aug 1960 173 104
27 - 28 Sept 1960 348 92
22 - 23 Aug 1961 110 64
10 - 11 Sept 1961 118 44
2 - 3 Oct 1961 516 161
25 - 26 July 1962 117 44
22 - 23 Sept 1962 152 45
28 - 29 Sept 1963 216 41
2 - 3 Oct 1963 451 121
24 - 25 Oct 1963 465 91
- A cusec is one cubic foot per second. Source: D.V.C. Data Book (1966).
Secondly, the relationship between the flood discharge and the area affected is stated to
be as in Table 6
Table 6: Relationship between Flood Discharge and Area Affected
Flood discharges Region affected Area in square miles
Less than 100,000 cusec None 0
100,000 to 200,000 cusec Amta - Mudeswari 300
200,000 to 300,000 cusec Amta - Mudeswari and Raina Area 500
300,000 cusec and above Amta - Mudeswari, Raina and left-
bank area
1500