بهینه نمودن و منطقه بندی ضرایب هیدرودینامیکی آبخوان دشت زاهدان با استفاده از مدل ریاضی جریان

Zahedan city is located in south eastern of Iran on the Zahedan plain aquifer. A huge mass of water is extracted from the mentioned aquifer for urban, industrial and agricultural demands. According to recent drought and also much extraction, water table has decreasing in recent years. In this research, by inputting the necessary data such as kind and number of layers, top and bottom of the layers elevation, water table elevation in observation wells and modifying model domain in PMWIN V۵.۳ software environment, the initial basic structure for the model was made. In the next step according to the provided plain unit hydrograph, water table elevation in December ۱۹۹۸ was imported to the model as initial hydraulic head and model was calibrated for steady state condition. After optimizing the horizontal conductivity coefficient at steady state condition, Model was calibrated at transient condition for one year from December ۱۹۹۸ to ۱۹۹۹ and then was verified for three years from ۱۹۹۹ to ۲۰۰۲. By performing these steps and considering suitable values and zonings, the horizontal hydraulic conductivity and specific yield coefficient of aquifer were optimized. Horizontal hydraulic conductivity was estimated maximum ۴۳m/day in north western and minimum ۱۸m/day in north eastern of the plain. The specific yield was calculated maximum about ۰.۲۴ in west and minimum about ۰.۰۸ in south eastern of the plain. The unit hydrograph of the plain and also model outputs show about ۸cm average drowdown annually.