Morpho-climatic study of gully erosion in arid areas, Case study: Qom province

Gully erosion is one of water erosion types that happen due to improper management of agricultural lands. The main objectives of this research are zonation and characterisation of gully erosion. For this purpose، affected areas by gully erosion were noticed in Arial photographs and satellite images. Areas with more than 500 ha and their dominant climates were specified with climate map and for each climate two areas in which one representative gully and two repetition gullies were chosen. Morphology characteristics، soil sampling and other related studies were performed in each gully. Consequently، according to the main characteristics، such as climate and view plan، these gullies were classified by cluster analysis and their digitized zonation maps were provided. According to the results، six regions with a total area of 7437. 3 ha were affected by gully erosion with three different types of climates، from which، three regions had moderately arid climate (Qeshlagh Alborz and Naizar) and warm semi-arid (Rahjerd) with more than 500 ha. These regions that are classified in two classes based on cluster analysis، have lateral gullies which are developed beside the natural drainages and are classified as un continuous gullies. The texture of soil surface is usually sandy-loam and in some cases loam and silty-loam and sandy-loam and silty-loam in the subsurface layer. Highly sensitive lands، flood occurrence، past heavy rainfalls and high amount of salts in some areas، are from the most morpho-climatic factors causing gully erosion in dry regions and deserts of Qom province.