Characteristics of kalisirah karst subterranean stream subdistrict of buayan, kebumen, central java with tracing test

Abstract

Abstract The Karst Landscape Region (KRL) Gombong is an area that has developed subterranean stream and provides abundant water resources, one of which is the Kalisirah Springs in Sikayu Village, Buayan District, Kebumen. The Kalisirah spring supports thousands of surrounding communities, especially for domestic needs, fisheries and agriculture. The karst area is an area that is sensitive to change so it is necessary to know the character of a developing subterranean stream system, so that groundwater resources can be maintained in terms of quality and quantity. The method used is a tracing test with a qualitative and quantitative approach to obtain detailed information about the characteristics of the karst aquifer flow. Release of trace substances is carried out in Goa Pucung and the fluorometer is placed in the Kalisirah Springs. Release on September 23, 2018 at 9.57 p.m and September 24, 2018 at 3.25 p.m. Fluorometer records an increase in fluorescent concentration. Connection of Goa Pucung-Kalisirah through 2 karst windows (Kalijeblosan and Kaliwinong) that are visible in plain view. The concentration of released tracer substances can be recovered 26.18% in the Kalisirah springs, with discharge recovery reaching 4493%, which indicates a divergence and convergence of the Kalisirah subterranean stream aquifer system. Flow volume from the subterranean stream system of Goa Pucung-Kalisirah reached 23,403,064.49 liters with an average residence time of 24.11 hours. The cross-sectional area is 12.19 m2 and the diameter of the Flow-Channel reaches 3.94 m, and with hydraulic depth from the Flow-Channel 3.09 meters.