The potential of river discharge at the peak of the dry season in some disaster-prone area of Merapi Volcano

With a high level of volcanic activity and many people living in the disaster-prone area, sustainable disaster management in the Merapi Volcano area is still very much needed in the future. One of the needs in building disaster management is ensuring water resources available during the pre-eruption period. So far, springs are the primary source of water that has been widely used by residents in the volcanic foothills, which are prone to eruption disasters. However, at the time of the eruption, many springs were not functioning so that alternative water sources were needed. River water can be an alternative water source, and a study of river water's potential is required to ensure its feasibility. This study was conducted on the south to the southwest side of Merapi Volcano to analyze the quantity and quality of river water as an alternative water source. Data collected through observation, literature study, and document search. Data analysis performed using descriptive analysis, matching analysis, and statistical analysis using independent sample t-test and simple linear regression. The study results show that seven rivers in the south to the southwest slope can be used as water sources because they are not lava flows. These rivers have varying discharge and water quality. There is no difference in discharge and water quality between the top and the bottom of the volcano foot. When dry season is on the peak, three rivers have no flow because some springs locations are at the volcano's bottom. Overall, based on these findings, it can be emphasized that the use of water sources is needed to do at the closest point to the evacuation barracks. However, a water treatment installation needs to be provided in the evacuation barracks so that the river water is suitable for consumption.