The Ponjong Hydrogeological Subsystem is a part of the Gunungsewu Karst Area on Java Island, Indonesia, and is uniquely influenced by allogenic recharge. This allogenic river system exists because the karst in this subsystem develops over a Tertiary volcanic formation. The contact between the Wonosari Formation limestone and the volcanic rocks, primarily composed of explosive volcanic materials from the Semillir Formation, allows this system forming. In this area, allogenic river catchments are dominated by relatively impermeable volcanic rocks and steep gradients, which often lead to flash floods. This study aimed to determine the characteristics of the cave and conduit networks within the underground river system influenced by allogenic recharge. An artificial tracer test using fluorescent dyes with breakthrough curves recorded by a fluorometer was conducted. Data analysis revealed that large, single conduits predominantly shape the cave networks in the study area. Due to the large discharge and steep gradient of the underground river system, a single conduit is formed instead of a maze-like cave system. The identification of connectivity between the allogenic rivers and the Gremeng Resurgence highlights that the karst drainage basin of the Gremeng Resurgence is not part of the Beton Karst Drainage Basin, as previously suggested by researchers who used methods other than artificial tracer tests. The development of large underground river systems indicates a high vulnerability to groundwater pollution and the ability to release groundwater reserves quickly. This poses a challenge for future environmental management, particularly in relation to water quality and water resource quantity management.

Keywords: allogenic river, artificial tracer test, dissolution passage, fluorescent dyes

REFERENCES

Abdulrazzaq ZT, Ahmed MM, Salih SA, Asfahani J (2022) Hydro-geophysical parameters estimation of porous aquifer using geoelectrical technique – case study from Baiji-Tikrit Sub-Basin, Iraq. ANAS Transactions Earth Sciences 1:3–16. https://doi.org/10.33677/ggianas20220100068

Adji TN (2011) Baseflow separation of the Bribin River Upstream in Gilap Cave Flowage, Sewu Mountain Karst, Gunung Kidul, Yogyakarta. Jurnal Geologi Indonesia 6(3):165–175. https://doi.org/10.17014/ijog.6.3.165-175 (in Indonesian)

Adji TN (2012) Wet season hydrochemistry of Bribin Cave in Gunung Sewu Karst, Indonesia. Environmental Earth Sciences 67(6):1563–1572. http://dx.doi.org/10.1007/s12665-012-1599-x

Akmaluddin, Setijadji DL, Watanabe K, Itaya T (2005) New interpretation on magmatic belts evolution during the Neogene-Quaternary periods as revealed from newly collected K-Ar ages from Central-East Java, Indonesia. Proceedings Joint Convention Surabaya 2005 – HAGI-IAGI-PERHAPI. The 30th HAGI, The 34th IAGI, and The 14th PERHAPI Annual Conference and Exhibition. http://repository.ugm.ac.id/digitasi/download.php?file=3261

Auler AS (2013) Sources of water aggressiveness – the driving forces of karstification. In: Treatise on Geomorphology, vol. 6. Elsevier Inc., London p 23–28, https://doi.org/10.1016/B978-0-12-374739-6.00099-3

Behrens H, Beims U, Dieter H et al. (2001) Toxicological and ecotoxicological assessment of water tracer. Hydrogeology Journal 9: 321–325. https://doi.org/10.1007/s100400100126

Benischke R, Goldscheider N, Smart C (2007) Tracer techniques. In: Methods in karst hydrogeology. Taylor and Francis Group, London, p 147–170

Bronto S, Mulyaningsih S, Hartono G, Astuti B (2009) Waduk Parangjoho and Songputri Reservoirs: alternative eruption sources of Semilir Formation in Eromoko Area, Wonogiri Regency, Central Java. Jurnal Geologi Indonesia 4(2):79–92. http://dx.doi.org/10.17014/ijog.4.2.77–92 (in Indonesian)

Budiyanto E, Lestari EP (2019) Sensitivity of Gremeng Karst Spring to rainfall in its catchment area. Jurnal Geografi: Geografi dan Pengajarannya 17(1):63–70 (in Indonesian)

Cahyadi A, Agniy RF (2016) Breakthrough curve analysis for passage characterization in Pindul underground river system. https://osf.io/preprints/inarxiv/3bs2v/ (in Indonesian)

Cahyadi A, Riyanto IA, Adji TN et al (2018a) Hydrostratigraphy and its impact on the emergence of springs in the Panggang Sub-System, Gunungsewu Karst Region, Gunungkidul Regency. Proceedings of Seminar Nasional Geografi II organized by Himpunan Mahasiswa Pascasarjana Geografi (HMPG) UGM. https://doi.org/osf.io/preprints/inarxiv/pc9fv/ (in Indonesian)

Cahyadi A, Riyanto I, Irshabdillah MR et al (2018b) Inventory and characterization of allogenic river flow system in Karst Gunungsewu Area of Gunungkidul Regency. Research Report (Faculty of Geography, Universitas Gadjah Mada), Yogyakarta, Indonesia, 92 p. https://acadstaff.ugm.ac.id/karya_files/inventarisasi-dan-karakterisasi-sistem-aliran-sungai-alogenik-di-kawasan-karst-gunungsewu-kabupaten-gunungkidul-0eab08e1810838be9e4be72cdfe44ac7 (in Indonesian)

Cahyadi A, Adji TN, Haryono E, Widyastuti M, Agniy RF (2022) Tracing flow directions of the Pentung Allogenic River in Gunungsewu Karst Area, Gunungkidul, using artificial tracer test. IOP Conference Series: Earth and Environmental Science, vol. 1098 (1).  https://iopscience.iop.org/article/10.1088/1755-1315/1098/1/012048

Davis SN, Thompson GM, Bentley HW, Stiles G (1980) Ground-water tracers – a short review. Groundwater Journal 18(1):14–21. https://doi.org/10.1111/j.1745-6584.1980.tb03366.x

Eppelbaum L, Zheludev V, Averbuch A (2014) Diffusion maps as a powerful tool for integrated geophysical analysis to detecting hidden karst terranes. ANAS Transactions Earth Sciences 1-2:36–46

Field MS (2003) A review of some tracer-test design equations for tracer-mass estimation and sample-collection frequency. Environmental Geology 43:867–881. https://doi.org/10.1007/s00254-002-0708-7

Field MS (2005) Tracer-Test design for losing stream-aquifer systems. International Journal of Speleology 35(1):25–36. http://dx.doi.org/10.5038/1827-806X.35.1.4

Ford D, Williams P (2007) Karst hydrology and geomorphology. John Wiley and Sons Ltd., Chichester, West Sussex, United State of America, p 576. https://doi.org/10.1002/9781118684986

Gilli E (2015) Karstology – karst, caves and springs: elements of fundamental and applied karstology. CRC Press, Boca Raton, Florida, United State of America, p 256. http://dx.doi.org/10.1201/b18380.

Goldscheider N, Meiman J, Pronk M, Smart C (2008) Tracer tests in karst hydrogeology and speleology. International Journal of Speleology 37(1):27–40. http://dx.doi.org/10.5038/1827-806X.37.1.3

Haryono E (2011) Introduction to Gunungsewu karst. Field Guide. Asian Trans-Disciplinary Karst Conference. https://osf.io/preprints/inarxiv/7w2sh_v1

Haryono E, Barianto DH, Cahyadi A (2017) Hydrogeology of Gunungsewu Karst Area: field guide for the 2^nd annual scientific week of the association of Indonesian groundwater experts. https://osf.io/preprints/inarxiv/t5dgp/ (in Indonesian)

Hess JW, White WB (1989) Chemical hydrology. In: Karst hydrology: concepts from the Mammoth Cave Area. Springer, New York, United State of America, p 145–174

Imrani ZT, Zeynalova KZ, Hidayati GA (2023) A study of caves and their speleotourism potential in Azerbaijan. ANAS Transactions Earth Sciences 1:100–110. http://doi.org/10.33677/ggianas20230100097

Käss W (1998) Tracing technique in geohydrology. Balkema, Rotterdam, Netherland, 602 p

Leibundgut C, Maloszewski P, Külls C (2009) Tracers in hydrology. Wiley Blackwell, New York, USA, 432 p

Lestari Y, Haryono E, Fatchurohman H (2014) Identification of catchment area criticality level to determine management direction: case study of Beton Spring Catchment, Ponjong, Gunungkidul. In: Environmental ecology of Indonesian Karst Areas: maintaining the preservation of Indonesia's Karst Areas, Second Edition. Deepublish, Yogyakarta, Indonesia, p 52–65 (in Indonesian)

Palmer AN (2001) Dynamics of cave development by allogenic water. Acta Carsologica 30(2):13–32

Palmer AN (2007) Cave geology. Caves Books, Dayton, Ohio, United State of America, p.454

Pratiwi ES (2013) Weaknesses and constraints of the application of the EPIK method in determining intrinsic groundwater vulnerability zoning in the Gunungsewu Karst Area, Indonesia. In: Environmental ecology of Indonesian Karst Areas: maintaining the preservation of Indonesia's Karst Areas, First Edition, Deepublish, Yogyakarta, Indonesia, p 53–63. https://books.google.co.id/ books/about/Ekologi_lingkungan_Kawasan_Karst_Indones.html?id=i05iEQAAQBAJ&redir_esc=y  (in Indonesian)

Riyanto IA, Cahyadi A, Adji TN, Haryono E et al (2018) Connectivity analysis and characterization of passage using tracer test in epikarst spring of Panggang Sub system, Gunungsewu Karst Area. Proceeding of Indonesian Hydrogeologist Expert Community Annual meeting (in Indonesian)

Surono BT, Sudarno I, Wiryosujono S (1992) Geology of the Surakarta-Giritontro Quadrangles, Java: Bandung, geological research and development center, Indonesia, scale 1:100,000

Surono S (2008) Sedimentation of the Semilir formation in Sendang Village, Wuryantoro, Wonogiri, Central Java. Jurnal Sumber Daya Geologi 28(1):29–41 (in Indonesian)

van Bemmelen RW (1949) The geology of Indonesia. Vol. IA, General geology. Martinus Nijhoff, The Hague, Netherland

White WB (1988) Geomorphology and hydrology of karst terrains. Oxford University, New York, p 480

Worthington SRH (2011) Management of carbonate aquifers. In: Karst management. Springer, Dordrecht, Netherland, p 241–263