**4.6 HDI2 at Sutami sub-watershed**

The Z test analysis showed that p = 0.064 > α = 0.05 and this means the simulation and observation are not the same as the mean test while Mann–Whitney median test also showed the value of p = 0.0547 > α = 0.05 and this also indicates the same trend as indicated in **Table 1**.

The Qsimulation mean value was observed to be within the tolerance range of the Qobservation while the p-value > α = 0.05 indicates the simulation is not the same as the observation data but the analysis conducted at Sutami Dam showed that the simulation data can be accepted.

The results showed that the simulation can be used to predict the drought in the Sutami sub-watershed for 2007–2014 with the dry limit observed to be at 0.000 < HDI < 0.0119, the very dry limit at 0.0059 < HDI < 0.000, and the extremely dry limit at HDI < 0.0059. The analysis further indicates that the lowest HDI value that has ever occurred was 0.006 which is included in the extremely dry criteria.
