. Choose the correct answer from the followings: 1. The double mass curve technique is used to a) estimate the missing rainfall data b) check the consistency of raingauge records c) find the average rainfall over a number of years d) find the number of raingauge needed 2. Virgin flow is a) the flow that would exist in the stream if there were no abstractions to the precipitation b) the flow unaffected works of man c) the flow in the river downstream of agauging station d) the flow in the river downstream of agauging station 3. A mean annual runoff of 1 m³/sec from a catchment of area 31.54Km² represents an effective rainfall of a) 100 mm b) 100 cm c) 1.0 cm d) 3.17 cm 4. In Horton's infiltration equation fitted to data from a soil, the initial infiltration capacity is 10 mm/h, final infiltration capacity is 5 mm/h and the exponential decay constant is 0.5 h.Assuming the infiltration takes place at capacity rates, the total infiltration depth for uniform storm of duration 8hours is a) 80mm b) 60mm 5. Direct runoff is made up of c) 40 mm d) 90 mm a) overland flow and infiltration b) rainfall and evaporation c) surface run off, infiltration and evapotranspiration d) surface runoff,prompt interflow and channel precipitation.