A Review on Major Water Erosion Factors in Iran

Soil erosion in a given area depends on natural characteristics of the place as well as the rate of  human impact. In Iran, the Mediterranean precipitation regime and relatively high erosivity of rain, wide area of erodible soils/lithological formations, sparse natural vegetation in many regions and mountainous topography are main natural factors that affect soil erosion by water. Accelerated soil erosion is due to inaccurate human activities particularly by land misuse without considering its capability and capacity. Wast changing in land uses and removing surface protective cover are common phenomena in many parts of the country. Some features such as over grazing in ranges and ploughing inefficient dry farms in agricultural and natural resources areas; implementation of development projects such as road construction, building and mining, without taking into account principles of soil conservation are increasingly exacerbate the rate of soil erosion. Poor enacted legislation on the area of soil conservation as well as improper implementation should be considered as an important issues too which worsen the erosion situation. This article reviews and discusses above mentioned factors by means of some quantitative and qualitative data and examples countrywide.