INFILTRATION AND RAINFALL – RUNOFF RELATIONSHIPS IN A SMALL CATCHMENT IN NORTHERN TUNISIA
Infiltration plays a major role in calculations of runoff and of the amount of water available for percolation to the ground water. This paper presents and discusses two aspects of infiltration: measured infiltration capacity and infiltration derived from rainfall-runoff relations. The measured infiltration capacity, which can be said to correspond to the infiltration of ponded water, was measured at about 50 points during one week in April 1983. The measurements showed a great variation in infiltration capacity over the catchment. The initial infiltration rate for the first half minute varied between about zero and up to more than 2000 mm/h. The various infiltration capacities seemed to be randomly distributed over the catchment. By studying precipitation-runoff relationships a lumped picture of the areal infiltration properties is obtained. Thirty rainfall-runoff events in the catchment as a whole and 24 rainfall-runoff events in the rural sub-catchment have been analyzed. The runoff volume showed a strong correlation to the rain volume. “Complete abstract not presented.”