Investigation of the effect of Haloxylon planted on groundwater resources (Case study: Jafarieh plain Qom)

Investigation of the effect of plant community on limited water resources of deserts is an important issue in water resources management. Different species of Haloxylon are compatible with desert condition and can use groundwater resources due to deep roots and proper structural condition. The purpose of this study was investigation of the effect of Haloxylon planted forests on groundwater resources in Jafarieh plain. For doing the study, at first the number of Haloxylon plants was determined in these forests using satellite images and JMicroVision software. Then using minimum water requirement of each plant, estimated with lysimeter, the number of surplus plants was determined based on their water requirement and rainfall of the region. Then groundwater level status was determined using GMS 8.3 software and MODFLOW model. The results showed that the number of Haloxylon plants in the study area was equal to 3746291 and the amount of groundwater evacuation by these plants was equal to 56.194 Mm3. The reduction of groundwater table was about 0.46 meter in the first study period (1992-2001) and 0.93 meter in the second study period (2002-2012) so that the reduction of groundwater level in the second study period was about 2 times bigger than the first study. This results showed that severe reduction of groundwater table has happened in recent decade because of planting Haloxylon. However the positive effects of these forests on reducing damages of dust storms should not be ignored.