Mahtab Safari Shad1, Mahmoud. Habibnejad Roshan, Alireza Ildoromi and Maryam. Dashti Marvili
According to the studies, about 60 percent of surface waters and 57 percent of ground waters in our country originate in snowy peaks. In the most of the northern hemisphere and specifically in Alpine areas, snow melt runoff both causes the instantaneous flow peaks and constitutes the better part of the annual debit. Considering the problems posed by field monitoring and measurement of snow coverage surfaces in mountainous areas, satellite imagery is now considered a viable alternative. In the present study, we set out to investigate a section of Gharachai Basin as a representative case. Data collected via Terra satellite was used in tandem with MODIS for calculation of daily variations of snow coverage surface area. For the days for which no satellite data were available, we substituted the use of daily measured temperature and snow density data. Daily variation of snow coverage surface area was compared against variation in debit, both recorded for a period of two years. Results show that snowmelt runoff has a drastic effect on the debit and this effect is more pronounced in the month of April. Hydrographs representing the basin show that the snowmelt period corresponds to the highest monthly water table. It can be seen that snowmelt causes the increase in and maximization of the groundwater and surface water volume in the area; the issue is hence important for water resource planning.
