85. The elevation Z of the watershed is
A. reduced level of the top most point of the basin
B. reduced level of the lower most point of the basin
C. average elevation of the highest and lowest point of the drainage basin
D. obtained by the formula + a2z2 + a3z3 +

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86. Run off is measured in
A. cubic metres
B. cubic metres per sec.
C. cubic metres per minute
D. cubic metres per hour.

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87.  The time required by rain water to reach the outlet of drainage basin, is generally called
A. time of concentration
B.time of overland flow
C. concentration time of overland flow
D. duration of the rainfall

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88.  Time of overland flow, is affected by
A. slope of the basin
B. type of the ground surface
C. length of the flow path
D. all the above.

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89.  The initial basin recharge is equal to
A. interception
B. depression storage
C. rain absorbed by the moisture deficiency
D. all the above.

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90.  The run off a drainage basin is
A. Initial recharge + ground water accretion + precipitation
B. Precipitation + ground water accretion + initial recharge
C. Precipitation ? ground water accretion + initial recharge
D. Precipitation ? ground water accretion ? initial recharge,

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91.  For computing the run off volumes of large areas, number of infiltrations used are
A.2
B.3
C.4
D.5

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