PREDICTING RAINFALL-RUNOFF EROSIVITY FOR SINGLE STORMS IN NORTHERN IRAQ

Estimation of soil loss from single storm events is essential for basi n planning and nonpoint source pollution control. Rainfall-runoff eros ivity factors for single storm events in northern Iraq were derived fr om the basic theory of soil detachment and transport. The factors deri ved are a single parameter which includes runoff depth only and a fact or which combines runoff depth and peak rate. These two erosivity fact ors gave satisfactory results when tested using data from natural runo ff plots collected at different sites in the region. The same data wer e then used to test the applicability of various established erosivity factors. The two derived erosivity factors were superior to any known erosivity factor tested in the region. These include factors currentl y in use in Universal Soil Loss Equation (USLE) applications in differ ent parts of the world.