Analisis Konektivitas Dan Karakteristik Lorong Pada Sistem Hidrogeologi Mataair Beton, Kawasan Karst Gunungsewu, Kabupaten Gunungkidul Dengan Uji Perunutan

Abstract

Pemahaman tentang sistem hidrogeologi dan wilayah tangkapan air dari sebuah mata air sangatlah penting. Hal ini untuk membantu pengelolaan yang menjaga kelestariannya. Mataair Beton merupakan salah satu mataair yang memiliki peranan yang sangat penting di wilayah Ponjong, Kabupaten Gunungkidul. Suplai air dari mataair ini digunakan untuk memenuhi kebutuhan air bersih, irigasi persawahan dan perikanan. Penelitian ini bertujuan untuk mengetahui konektivitas dan karakterisasi lorong di sistem hidrogeologi Mataair Beton. Metode yang digunakan adalah tracer test dengan menggunakan fluorescent dyes. Hasil analisis menunjukkan bahwa Ponor Seropan memiliki konektivitas dengan Mataair Beton, dan memiliki karakteristik lorong berupa single conduit. Perkembangan lorong yang lanjut menunjukkan bahwa sistem hidrogeologi di lokasi kajian sangat dipengaruhi oleh imbuhan airtanah dari sistem alogenik yang berhulu di wilayah non-karst dan memiliki kerentanan terhadap pencemaran airtanah yang tinggi.Kata Kunci: Karst, Sungai Alogenik, Kawasan Karst Gunung Sewu, Uji Perunutan, Mataair BetonAn understanding of the hydrogeological system and catchment area of spring is very important. This is to help manage that maintains its sustainability. Beton Resurgence is one of the springs that have a very important role in the Ponjong area, Gunungkidul Regency. Water supply from the spring is used to supply clean water, irrigated rice fields, and fisheries. This study aims to determine the connectivity and characterization of Passage in the Beton hydrogeological system. The method used is a tracer test using fluorescent dyes. The results of the analysis of breaktrough curve indicate that Seropan Sinking Stream has connectivity with Beton resurgence, and has passage characteristics in the form of a single conduit. The further development of the passage shows that the hydrogeological system is strongly influenced by groundwater recharge originating from an allogenic system that originates in non-karst areas and has a high groundwater vulnerability to pollution. Keywords: Karst, Allogenic River, Gunungsewu Karst Area, Tracer Test, Beton Resurgence

Hydrogeological Characterization of the Gunungsewu Karst Area in the Upper Reach of Gremeng Karst Drainage Basin, Indonesia

“…BTCs of the three locations formed three separate single curves with steep rising and falling limbs, indicating that the conduits developing along the underground rivers have large slope gradients. Similar results were found in the conduit of the Beton Karst Drainage Basin, which shares the same geological characteristics with this research, located at the transition between Semilir and Wonosari Formations and in the same hydrogeological subsystem (i.e., Ponjong Hydrogeological Subsystem) [16]. Single BTCs also indicate that the three locations have single conduits.…”

“…Cahyadi et al (2019; 2020) [15,16] divide the northern segment of the Ponjong Hydrogeological Subsystem into two karst drainage basins: Beton and Gremeng, but have not discussed it in detail. Therefore, the current research set out to complement previous studies that merely separated the subsystem's northern part from the Bribin Karst Drainage Basin.…”

Tracing flow directions of the Pentung Allogenic River in Gunungsewu Karst Area, Gunungkidul, using artificial tracer test

“…This finding corresponds to Palmer [16,17], which explained that the underground tunnels influenced by allogenic rivers are generally single or in the form of caves with numerous branched passages (maze caves). The current research confirmed the artificial tracer test results conducted in the Seropan Ponor-Spring Beton system [15] and the cave passages in the upper course of the Gremeng KDB fed by the allogenic flows from the Panggung Masif Hills. The BTC presented in Figure 2 also showed connectivity between Jomblangan Cave and Beton Spring.…”

“…Therefore, it can be inferred that the groundwater flows from Sawah Ombo to Jomblangan Cave through a developed single conduit before it appears in Sriti Spring and flows as a surface river. The surface river then enters Seropan Ponor, which is connected to Beton Spring through a single large conduit [15]. The prediction of the flow from Pentung River to Beton Spring is presented in detail in Figure 4.…”

“…An artificial tracer test by Cahyadi [13,14] discovered that the western part of the allogenic river in the Ponjong Hydrogeological System supplies groundwater to Gremeng Spring instead of to Bribin KDB and that Gremeng KDB is separate from Beton KDB. According to another artificial tracer test by Cahyadi [15] at Seropan Ponor, it turns out that the river draining to the ponor (including from Sriti Spring) flows to Beton Spring through a single conduit of reasonably large size. These findings then raised a question as to whether the water from Sawah Ombo Pond flows directly to Beton Spring and partially leaks at Sriti Spring before reaching Seropan Ponor or entirely flows through Sriti Spring to Seropan Ponor and then Beton Spring.…”