The study to update the Development Plan of 1973, prepared by NEDECO for the Jratunseluna Basin, has been completed. All projects in the constituting sub basins (Figure I-1), studied and reported by previous investigators and those identified during the course of this study were examined individually. Then, different combinations of projects were analyzed to produce a logical and viable scheme for the overall development of the water resources of the entire basin. The optimization of the development plan was derived with the help of a mathematical model of the basin (Figure 1,-2). The physical characteristics of the basin, potential irrigation. service areas (114,840 ha), projected demands for M & I water in the city of Semarang (4,000 l/s), and existing and potential hydropower generating: stations were incorporated in the model. The potential irrigation areas are shown on. Figure 1-3. The simulation studies of the integrated operation of all the reservoirs, transbasin diversions, diversions: for irrigation and M & I water demands, and of the hydropower plants in the model, were done by computer application. The study was originally started in May 1979 to prepare an integrated development plan for the Tuntang and the Jragung River Subbasins. The scope of the study was subsequently enlarged, in. December.: 1979, to include all subbasins into a conceptual development plan for the entire Jratunseluna Basin. The conclusions drawn from the study and the recommendations made by the Consultant are summarized in 'the following.