Analysis of water supply fulfillment for watering plants needs in potentially upcoming El Nino period using reliable discharge and planned rainfall discharge methods

Based on the statement from the Meteorology, Climatology, and Geophysics Agency (BMKG), Indonesia is potentially entering a period of El Nino and facing below-normal dry conditions that lead to drought. The Environmental Service of Surabaya City (DLH), that in charge of watering city parks every day is affected because this watering process utilizes water from existing water channels as its source. During the El Nino period, it is feared that the water channels will dry up, resulting in insufficient water supply for watering. The solution then is to analyze the water supply fulfillment. The method used is calculating the planned rainfall discharge to determine the water level in the rainy season and the reliable discharge to determine the water level in the dry season. Comparing the two water levels, the difference in water levels is then used to calculate the required water discharge. Through this analysis, it is found that the water demand during the dry season increases by 130 percent, reaching 676,000 liters. However, the water level in the existing channels decreased to 0 meters in July. Besides, the availability of alternative water from WWTP reaches 846,700 liters, which is sufficient to fulfill the watering water demand.