41.The unit Iwdrograph due to a storm may be obtained by dividing the ordinates of the direct runoff hydrograph by direct runoff volume
42. The unit hydrograph of a specified duration can be used to evaluate the
hydrograph of storms of any duration
43. S-hydrograph is used to obtain unit hydrograph of shorter duration from longer duration,longer duration from shorter duration .
44. If two 4-hour unit hydrographs are staggered by 4 hours and added graphically, the resulting hydrograph will be 8-hour hydrograph with 20 mm
runoff
45. According to Dicken's formula for estimating floods, the peak discharge is
proportional to
where A is catchment area in square kilometres
46. The relation between probability (P) and recurrence interval (T) is given by
PT = 1
47. Dimensions of coefficient of transmissibility are
48. If d is the depth of the aquifer through which water is flowing, then the relationship between permeability k and transmissibility T is given by
T = kd
49. An artesian aquifer is the one where water is under pressure between two
impervious strata
50. A deep well has more discharge than a shallow well
51. A multipurpose reservoir is the one which is planned and constructed to serve
various purposes
52. The useful storage is the volume of water stored in the reservoir between minimum pool level and normal pool level
53. The water stored in the reservoir below the minimum pool level is called
dead storage
54. For a flood control reservoir, the effective storage is equal to useful storage + surcharge storage -valley storage
55. Trap efficiency of a reservoir is a function of capacity/inflow ratio
56. The total capacity of a reservoir is 25 million cubic metres and dead storage is 5
million cubic metres. If the average volume of sediment deposition is 0.10
million cubic metre per year, then the usefulness of the reservoir will start
reducing after 50 years
57. The forces, which are considered for the analysis of an elementary profile of a
gravity dam under empty reservoir condition, are Self weight
58. When the upstream face of a gravity dam is vertical, then the intensity of water pressure at the water surface and at the base respectively will be 0 and wH
59. The uplift pressure on a dam can be controlled by constructing cutoff under upstream face,constructing drainage channels between the dam and its foundation,by pressure grouting in foundation
60. The uplift pressure on the face of a drainage gallery in a dam is taken as
two-third of hydrostatic pressure at toe plus one-third of hydrostatic pressure at heel
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