Subsurface Flow and Surface Water Interactions Quantification in Gunung Kidul Karst Area Using Hydro- Chemical and Stable Isotopes Data Variations

Abstract

Subsurface flow is one of the available water sources in the Karsts area such as in GunungKidul. The study of the pattern of the variations of stable isotopes content as a function oftime and its interaction with other water sources such as rain waters, groundwater, riverwater will be a very good tool to assess the potential of the subsurface flow as a water source.For this purpose, the variations of stable isotopes content of subsurface flow around GunungKidul Karsts area and its interactions with other local water sources have been studied for thelast two years. From the comparison of stable isotopes variations pattern of the subsurfaceflow with monthly rain water, the interaction of the subsurface flow with other water sourcesin the area has been quantified. Based on hydro-chemical data, it was found that the rechargearea of subsurface flow were relatively further than other samples and it was also found thatSeropan and Bribin subsurface flow systems originate from different geologic structures.Based on stable isotopes relative contents, it was found Ngobaran and Baron Caves have beenmixed with domestic sewerage water or other surface water.Keywords : Karsts area, stable isotopes, subsurface flow

Upstream Hydraulic Interconnection Study of Gunungkidul Karst Area Underground Rivers

“…Hydrochemical contents of collected samples are very important parameters to trace back the geological formation that water has passed through due to the fact that water is a good solvent [10]. and oxygen-18 ratio ( 18 O), respectively and is given in equations 1 and 2 [12].…”

Studi Daerah Imbuh Sistem Air Sungai Bawah Tanah Gunungkidul–Yogyakarta Menggunakan Isotop Stabil δ18O dan δ2H

“…Kebutuhan terhadap air semakin lama semakin meningkat seiring pertumbuhan penduduk dan perkembangan industri [1,2]. Karena kondisi geologi, tidak semua daerah memiliki ketersediaan air yang cukup untuk memenuhi kebutuhan masyarakat di sekitarnya, seperti yang terjadi di daerah Gunungkidul yang umumnya didominasi oleh batuan gamping [3]. Untuk memenuhi kebutuhan air, penduduk biasanya banyak memanfaatkan air yang berasal dari mata air yang muncul di beberapa lokasi.…”

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

“…A tracer (possibly, Sulforhodamine B) injected in Sawah Ombo Pond was expected to emerge in the Bribin Underground River; instead, it appeared in Beton Spring and caused the water in Beton Dam to turn red. Subsequent hydrogeochemical studies using natural isotope and injection of an artificial tracer (uranine), e.g., Sidauruk et al [10,11], found that Sawah Ombo Pond was connected to Sriti Spring. Sidauruk et al [11] mentioned that the spring is a leak of the underground river system from Sawah Ombo Pond to Beton Spring.…”

“…However, it ignored the existence of Jomblangan Cave, which the Faculty of Forestry UGM [2] claimed was connected to Sawah Ombo Pond, and Seropan Ponor, which is the headwater of Sriti Spring (unknown lower course). Also, based on the natural isotope analysis, Sidauruk et al [10] explained that Sawah Ombo Pond does not issue water to the Bribin Underground River even though no artificial tracer test was performed in this section. Later, Setiawan et al [12] corroborate the findings of Sidauruk et al [10] through natural isotope analysis.…”