4 Discussion

Trend analysis results of all the relevant factors in the water resource management of the watershed over time (Figure \ref{574713} and Table \ref{974045}) indicated that precipitation, discharge, and cultivated area have not displayed any significant trends. These factors were trend-free, while the inter-basin water transfer tunnel showed a positive trend and the aquifer storage volume experienced a drastic negative trend. Therefore, there is an imbalance between the inflow and outflow. Otherwise, there was either an upward or downward trend in the discharge of the Eskandari station (watershed outlet). The imbalance suggested a water loss during the period. So, we first determined the extent of water loss in the watershed, and then investigated the plausible factors contributing to this water loss.