TY - CONF EP - 27 UR - https://itny.ac.id ID - ITNYREPOID1790 Y1 - 2016/10/10/ SP - 23 N2 - Eruption of Mount Merapi in 2010 ago had an impact on the quality of surface water, but no clear effect on the groundwater. Code Sub-drainage Area is an affected area of the volcanic eruption, because the river is located on the slopes of Merapi and its upstream comes from the upper slope of the mountain. Groundwater flows in the area surrounding the River Code in south direction, with gradient flow smaller in the downstream direction. This flow pattern resembles the surface topography. Types of shallow groundwater chemistry is dominated by sodium calcium ? bicarbonate water, consist of Ca-HCO3; Ca-Cl,SO4,HCO3; Na,Ca-HCO3 whereas the hydrochemistry types of deep groundwater is more varied (Na,Mg-Cl,HCO3; Na,Ca,Mg-SO4, HCO3 and Na, Ca,Mg-HCO3. Groundwater from the springs which were found has the type of Na,Mg ? Cl,HCO3. The hydrochemistry of groundwater is highly dependent on the Merapi volcanic rock aquifers, espcially from Yogyakarta Formation and controlled by mixing and leaching hydrochemical processes. Keywords- hydrochemistry, groundwater, Code Sub-drainage Area. A1 - T. Listyani, R.A. AV - public TI - Hydrochemistry of Groundwater in Yogyakarta Graben Area of Code Sub Drainage, Yogyakarta, Indonesia M2 - Singapore T2 - 16. 5th Annual International Conference on Geological & Earth Sciences (GEOS 2016), GSTF, Singapore (2016) KW - hydrochemistry KW - groundwater KW - Code Sub-drainage Area. hydrochemistry KW - groundwater KW - Code Sub-drainage Area. hydrochemistry KW - groundwater KW - Code Sub-drainage Area. ER -