Tjahyo Nugroho Adji

Diffuse flow characteristics and their relation to hydrochemistry conditions in the Petoyan Spring, Gunungsewu Karst, Java, Indonesia

This study was conducted on the Petoyan Spring, one of the most important springs in the western part of Gunung Sewu Karst, Java, Indonesia. The main purpose of the study is to define the diffuse flow characteristics of the spring. It also focuses on identifying the relationship between the diffuse flow proportion and several hydrochemical parameters to provide a better aquifer characterization. Water-level monitoring and discharge measurements were conducted over an eight months period in order to define the discharge hydrograph. The calculation of recession constants, including the diffuse flow (Kb), fissure flow (Ki), and conduit flow (Kc), was done by selecting several flood hydrograph events. Furthermore, the base flow-separation analysis was conducted to determine the diffuse flow proportion throughout the research period. Water sampling for hydrogeochemical analysis was taken every week and every hour for two selected flood events. A bivariate plot analysis between the diffuse flow proportion and certain hydrochemical parameters was made in order to describe the hydrogeochemical processes. The results showed that the diffuse- flow significantly dominates the spring discharge during non-flooding and flooding recession periods. Conversely, during the rising limb period, the diffuse proportion decreased drastically due to the conduit flow supply. This fact was also supported by the high Kb and short Tp (time to peak) and Tb (time to base flow) values. Hydrogeochemically the correlation between the diffuse flow proportion and major dissolved elements during the flood recession periods was strong because the conduit flow domination was replaced by the diffuse flow, causing the domination of water-rock interaction. According to the diffuse flow and its relation to its hydrochemistry, it is apparent that small fractures in the Petoyan Spring aquifer still provide good storage for the diffuse flow, even though the conduit fracture has already been developed.

Spatial and temporal hydrochemistry variations of karst water in Gunung Sewu, Java, Indonesia

A hydrogeochemical study was conducted in the Gunung Sewu Karst, Java Island, Indonesia. The main objective of this study is to describe the spatial and temporal variations of hydrochemistry that occur in the central and western parts of Gunung Sewu. Discharge measurements for a one-year period are taken in some karst springs or underground rivers to define their discharge hydrograph. Furthermore, baseflow separation analysis was conducted to determine the base flow percentage throughout the year. Water sampling for hydrogeochemical analysis was taken every month to represent the dry and rainy season conditions. To describe the hydrogeochemical processes, a scatter plot analysis with a small sample size was conducted. The results showed that the hydrochemistry of karst water in the study area has different characteristics spatially and temporally. Within the dry season, the dominant hydrogeochemical process is water–rock interaction (precipitation of calcite mineral), indicated by achieving the maximum level of Ca2+, HCO3−, electrical conductivity, base flow percentage, and SI calcite, with the lowest level of log

Application Of Water Table Fluctuation Method To Quantify Spatial Groundwater Recharge Witidn The Southern Slope Of Merapi Volcano, Indonesia

P_{{{\text{CO}}_{2} }}

Wet season hydrochemistry of Bribin Cave in Gunung Sewu Karst, Indonesia

PCO2 in the water. In addition, the dry season hydrochemistry is characterized by a strong relationship between electrical conductivity–calcium/bicarbonate, base flow percentage-discharge, base flow percentage-SI calcite, and SI calcite-log

The Investigation of Groundwater Potential by Vertical Electrical Sounding (VES) Approach in Arguni Bay Region, Kaimana Regency, West Papua

P_{{{\text{CO}}_{2} }}

Hidrostratigrafi Akuifer dan Estimasi Potensi Airtanah Bebas Guna Mendukung Kebutuhan Air Domestik Desa Sembungan

PCO2. Spatially, the different level of correlations between these parameters depended on the sampling location, flow recharge, and the conduit development. Conversely, in the rainy season, the hydrogeochemical process shifted from water–rock interaction to dilution of rainwater as a result of rain water supply through a conduit system channel, which is characterized by declining Ca2+, HCO3−, electrical conductivity, base flow percentage, and SI calcite, with the highest level of log