In the rational formula Q = CiA, the runoff coefficient C depends on:
Choose the correct answer
Rainfall intensity only
Land use and cover (impervious vs pervious), soil type (infiltration capacity), and catchment slope
Basin area only
Stream gradient only
Correct Answer
B. Land use and cover (impervious vs pervious), soil type (infiltration capacity), and catchment slope
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Runoff coefficient C: ratio of peak runoff rate to average rainfall intensity over time of concentration. C values: impervious urban (0.7-0.95), lawns/parks (0.1-0.35), agricultural land (0.2-0.5), forests (0.1-0.3). For composite catchments: C = sum(Ci x Ai) / A. Valid for small catchments (< 2.5 km2, T_c < 20 min).
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