Application of Tank Model and F.J. Mock for Water Management in the Sub Watershed Cikijing, Indonesia

Discharge conditions in rivers always change throughout the year. Changes in river discharge and water level must always be observed at all times both in the rainy season and dry season. There are two models used in this study to analyze the characteristics parameters of a watershed both in terms of quality and quantity using the Tank Model and F.J.Mock methods (FJMM). The purpose of the analysis using these two methods is to estimate the distribution of water flow vertically and horizontally based on time so that it can be known the availability of water in a watershed area. From the results of this study, the highest water availability with 90% discharge reliability in the Cikijing Sub-watershed for both methods was in February at 3.36 m3 /s for the Tank Model method and 3.11 m3 /s for the FJMM. Whereas the water demand in 2016 was obtained of 0.213 m3 /s, in 2019 of 0.240 m3 /s, in 2022 of 0.270 m3 /s, and in 2025 of 0.303 m3 /s. Water balance in 2016 and 2019 there were water deficits in July, August and September, while in 2022 and 2025 there were water deficits in July, August, September and October. The results of this study indicate that the discharge generated by these two methods is almost the same, however the Tank Model method is more recommended because the method analyzes more parameters in one watershed, so that the calculation results are more valid.