Empirical formula for determining Beanch terraces spacing in Duhok governorate

الملخص EN

As population increases rapidly, marginal lands are brought into cultivation where land pressures are high, Bench terraces are effective soil conservation must be approach to stop or reduce soil erosion on slope lands and retain runoff for moisture conservation, they were built without proper design using traditional methods , resulting in either high construction costs or limited use.

On the other hand, some design criteria are complicated which to restrain their application.

This study introduces a simple but scientific design for bench terraces after determining and comparing the study terraces parameters with their suited for our location and condition, which represent rainfall distribution, soil erodibility, soil management and land use.

The proposed equation is VI= 0.21S + 0.9 .Comparing our results in calculated design and that which real obtained on the study location shown many differences in number of terraces and vertical and horizontal interval, as well as neglect the effect of riser parameter in farmer terraces, also the value of soil loss was differ among the terraces and ranged from 7.55-25.17 ton/ha/year