Abstract
In this study, we investigated daily reservoir inflows and water volumes of Wonogiri dam and dry and wet seasons irrigated areas in the Solo River Basin, Indonesia, by applying the BTOP model with the Japanese Meteorological Research Institute (MRI)-Atmospheric General Circulation Model (AGCM)3.2S precipitation outputs of the Representative Concentration Pathways (RCPs) 8.5 emission scenario for the present (1/1979-12/2003) and future (01/2075-12/2099) climates. Wonogiri Dam is located in the headwaters of the Solo River basin and is a multi-purpose dam with the effective water storage capacity of 0.615 cubic km. From BTOP model results, Wonogiri Dam inflows increase during rainy seasons from November to March due increased future RCP8.5 precipitation of the MRI-AGCM3.2S outputs. In the future climates, the downstream irrigated area is expected to increase, especially in dry seasons, due to available water for irrigation in the reservoir and the period of fully occupied storage also increases indicating the ineffective dam discharge. As a result, there is a potential for new water resources development in the Solo River basin while the revision of Wonogiri dam operation rule is necessary for adjusting for the future climatic patterns.
