Estimated rate of karst aquifer development by MRC analysis and flood hydrograph components at Guntur Springs, Gunungsewu Karst Area, Indonesia

Understanding the stage of karst aquifer development (karstification) is of vital importance because this parameter can reflect the character of flow system release, from which relevant management patterns are derived. Master Recession Curve (MRC) construction is considered ideal for identifying at which stage karstification works because MRC relies on recession curves as its primary input. Recession curves are the most stable component of flow hydrographs in representing aquifer characteristics. The study focused on springs located in a karst hydrogeological subsystem, namely, Guntur Spring in the Panggang Hydrogeological Subsystem (Gunungsewu Karst Area). It was designed to determine (1) the flow characteristics and (2) the degree of karst aquifer development at Guntur Spring. It utilized a one-year flow hydrograph with a 30-minute logging interval as the main data. The flood hydrograph showed that a fissure system dominated the flow characteristics. Moreover, the MRC construction results indicated that the karstification level at Guntur Spring was 5.0, confirming the dominant fissure system and also signs of the recent development of conduit flows