Assessment of Aridity Using Geographical Information System in Zayandeh-Roud Basin, Isfahan, Iran

Rapid growth of population and human activities has caused a perceptible change in the climate in some parts of Zayandeh-Roud Basin (Z.R.B.).High temperatures and aridity in some parts are a growing environmental problem.Assessment and monitoring of aridity is essential to protect desertification and mitigate drought.A Geographical Information System (GIS) was used in this paper for the assessment of (Z.R.B) using climatic data collected from 11 stations situated in the basin.In order to assess aridity, three well-known aridity models, viz De Martonne Aridity Index, Thornthwait Precipitation Effectiveness index and UNESCO Aridity Index, were used.Result showed that climate of Z.R.B is mostly becoming drier.There exists a small climatically wet zone in the area.