Volume 16, No. 3, 2022
Received: 2022/02/09, Accepted: 2022/05/15
This study investigates the relation between the Wala dam monthly inflows and outflows and the main features of the monthly inflows that are obtained for the proper reservoir operation. The rainy season monthly inflows and outflows were obtained from daily data from November 2002 to April 2016. It has been found that water release schemes generally followed the rise and fall pattern of the monthly inflows and that major water release activities are delayed 1 month after major inflows without any consideration for nonflowing or low inflows in subsequent months. Regarding nonflowing months, the event of 1 month zero inflow usually occurs once every 2 rainy seasons, while zero inflow periods of 4 months or more are rare events. The analysis finds that January and February contribute about 50% of the total inflow enters the Wala dam while most of water release occurs in February and March each season. Finally, to predict the monthly inflow magnitude that is associated to a certain recurrence time, the Normal distribution can be used effectively after applying power transformation to normalize the inflows. Later the predicted normalized inflow is back-transformed to the original inflow domain.
Monthly inflow, Nonflowing months, Normal distribution, Wala dam.