The changes of the start in the wet season and dry season and potential electrical energy on wet season based on hydrology (Case: Kalijirak River, Karanganyar Regency)

Abstract Climate change causes changes at the beginning of the rainy season and the dry season. In Microhydro planning, determining the rainy season’s right start is very important to determine the energy potential. The beginning of the dry season is an excellent time to start carrying out structural work. This research was conducted in Kalijirak River, Mount Bromo Forest and Karanganyar Regency, a forest protected by the Indonesian government. The survey shows that the river flow is up to 1,458 m3/s in the dry season. This discharge is the potential to generate electrical energy. The construction must build in the dry season. This research aims to determine the beginning of the rainfall season to know the potential energy can generate and the beginning of the dry season to schedule the construction—analysis of seasonal changes based on rainfall intensity while analyzing energy potential based on dependable discharge. The rainfall-runoff simulation uses the Mock method to produce a dependable discharge. The results show that the beginning of the November rainy season period secondmeans that the rainy season shifts back four periods, and the beginning of the dry season in May period 2 means the dry season shifts back four periods). This means, if the season moves late, the start of construction is also late. It late up to fourPeriode. Besides that, it also shows that the annual energy potential is 64,774,372 kWh.