In recent years, due to development in agricultural activities in Iran, a considerable groundwater draft has been occurred in almost all plains this country. The plain of Bastam is one of these plains which its groundwater resources have been markedly diminished in last few years. In order to evaluate the groundwater draft in this plain, groundwater levels for an eight-year period (2000-2007) were collected and the unit hydrograph of the plain prepared. According to the unit hydrograph of the Bastam plain, it is obvious that there is a continuous decline in groundwater level in this plain. Comparing the precipitation of this plain from 2000 to 2007 with its average in a 21-year period reveal that the main reason for groundwater decline in this region is concerned to heavy groundwater discharge. Keywords: Bastam plain, unit hydrograph, groundwater draft

Bastam plain unit hydrograph groundwater draft