Document Type : Research Paper

Authors

• Mohammad Nasrollahi
• Maryam Mombeni
• Sara Valizadeh
• Hasan Khosravi

Abstract

Oneof the direct methods of land use impacts on thehydrological conditions of each region is the relation between landuse changes and the groundwater table fluctuations that can assistmanagers in optimal management of natural resources. In thisstudy, to evaluate the impacts of land use changes on thegroundwater level drops in Gilan-E gharb plain, satellite imagesfrom MSS, TM and ETM sensors in 1985, 2000, 2010 were used. Afterprocessing and analysis of images, the region were classified intosix classes in terms of land use including forest, pasture, dry and water farming, farming, and residential areas. Quantitative statistics of piezometric wells in the plain during1999 -2010was used to examinethe aquifer changes and the resulting layerswere also classified. The results showed that pasture land useholds the largest area with more than 50% of the maximum area, so thatit formed 61.8% (9927 ha) and 67.15% (10782 ha) of the area in1985and 2000 respectively. Its area has decreased during the period from2000 -2010,so thatit has covered 50.23% (8066 ha) of the region in 2010. Evaluation of dry andwater farming also showed that it has facedan area reduction of 0.84% (130 ha) during1985-2000,but these changes in the period of 2000 to 2010 has increased to 1429ha which formed 8.9% of the region. Investigating the rate of groundwater dropsshowed that ground water drop has increased by replacing the pasture land use class with water and dry farming classes.These changes have caused 83.93% ofthe area to have a groundwater drop of more than 50 cmper year in 2010, so that the area of this region has been43.85% of the regionin 2000. Human intervention is undoubtedly one of the most important factors ofthe region destruction.

Keywords

• Land use changes
• Satellite images
• Groundwater table
• Zonation؛ Gilan-e gharb plain