Hazardous zoning of Aleshtar plain karst aquifer with cap model

Karst aquifers in semi-arid regions play a vital role in people's lives. Therefore, recognizing the pollution potential of aquifers and their vulnerability in different sectors is very important. The western region of Iran, due to the expansion of the Zagros carbonate mountain range, has numerous karstic aquifers that are exposed to pollution in terms of environmental conditions and extensive human activities. The purpose of this study is to estimate the vulnerability map of Aleshtar plain karst aquifer located in Lorestan province against COP pollution. This model evaluates the vulnerability of karst water sources to pollution using three factors, cover layer (O), flow concentration (C) and precipitation regime (P). The results show that 19.14, 28.76, 35.01 and 17.09% of the area are located in very low, low, medium and high vulnerability zones, respectively, which indicates the almost low vulnerability of this karst aquifer compared to It is pollution. Findings indicate that the importance of the overlay factor, precipitation regime factor and flow concentration factor in the pollution of Aleshtar aquifer, respectively. Due to the small area of ​​fully developed karsts and the high slope of areas with developed karst, the role of flow concentration factor in pollution of Aleshtar aquifer is less and due to the drought trend of recent decades and the change of precipitation from snow to rain showers that water retention and therefore less penetration In the karst basin of Alshtar, the importance of the rainfall regime in the vulnerability of the Alshtar aquifer has decreased. Finally, due to the high permeability of the alluvial plain of Aleshtar, the cover layer has provided the ground for aquifer pollution. In general, in the study area, C, P and O, respectively, have the most role in the vulnerability of the area.