Diffuse flow separation in the three largest springs on the north side of the Karangbolong karst area, Central Java, Indonesia

2021 ◽  
Author(s):  
Danang Riza Fauzi ◽  
Tjahyo Nugroho Adji ◽  
Andy Setyawan ◽  
Aulia Ika Rahmawati ◽  
Danung Shodikh Makhrizal ◽  
...  
Keyword(s):  
Flow Separation ◽  
Karst Area ◽  
Diffuse Flow ◽  
The North ◽  
Central Java ◽  
North Side

Analysis of floods recession constant of several karst springs in the north side of Karangbolong (Gombong) karst area, Central Java

2021 ◽  
Author(s):  
Danang Riza Fauzi ◽  
Tjahyo Nugroho Adji ◽  
Andy Setyawan ◽  
Aulia Ika Rahmawati ◽  
Danung Shodikh Mahrizkhal ◽  
...  
Keyword(s):  
Karst Area ◽  
Karst Springs ◽  
The North ◽  
Central Java ◽  
North Side ◽  
Recession Constant

scholarly journals DIFFUSE FLOW SEPARATION WITHIN KARST UNDERGROUND RIVER AT NGRENENG CAVE

2017 ◽  
Author(s):  
Tjahyo Nugroho Adji ◽  
Heru Hendrayana ◽  
Sudarmadji ◽  
Suratman Woro
Keyword(s):  
Water Level ◽  
Flow Separation ◽  
Karst Aquifer ◽  
Digital Filtering ◽  
Base Flow ◽  
Karst Area ◽  
Flood Events ◽  
Wet Season ◽  
Diffuse Flow ◽  
Underground River

Diffuse flow is a dependable flow to recharge karst underground river within the dry season. Thisresearch is conducted at Ngreneng Cave, which is famous as the leakage tributary of Bribin River, themost important underground river in Gunungsewu karst area, Central Java. The objective of this researchis to separate the karst flow components at Ngreneng Cave, in order to acknowledge the percentage ofdiffuse flow during the period of measurement. A water level data logger is installed during one yearperiod to understand the variation of water level within dry and wet season. Furthermore, to define StageDischarge Rating Curve, several discharge measurement is conducted within minimum, average andmaximum discharge condition. Afterwards, the diffuse flow separation from its total flow is conducted byusing automated base flow separation by digital filtering. The digital filtering values is acquired from theanalysis of recession constant value in the occurrence of flood events in a year observation and related tothe value of the base flow maximum indices (BFI) of karst aquifer. The result shows that during one yearobservation, Ngreneng Cave experiences 68 times of flooding, with digital filtering value of 0.992. Ingeneral, the monthly estimation of the diffuse flow percentage is very close to 80%, whereas it decreasesto 41-59% during flood events.

scholarly journals Groundwater Flooding due to Tropical Cyclone Cempaka in Ngreneng Karst Window, Gunungsewu Karst Area, Indonesia

2019 ◽  
Vol 125 ◽  
pp. 01020
Author(s):  
Ahmad Cahyadi ◽  
Eko Haryono ◽  
Tjahyo Nugroho Adji ◽  
M Widyastuti ◽  
Indra Agus Riyanto ◽  
...  
Keyword(s):  
Tropical Cyclone ◽  
Indian Ocean ◽  
Extreme Rainfall ◽  
River System ◽  
Karst Area ◽  
Diffuse Flow ◽  
Central Java ◽  
The Indian Ocean ◽  
Water Filling ◽  
Underground River

Tropical Cyclone Cempaka occurred on November 27, 2017 in the Indian Ocean, just south of Central Java. This incident induced high rainfall leading to flash floods in the southern part of Central Java, including Gunungsewu Karst Area. The highest rainfall recorded on November 28, 2017, in this area was 239 mm/day (Automatic Rainfall Recorder/ARR Station in Pindul Cave) and 341 mm/day (ARR Station in Tepus). The extreme rainfall also caused groundwater flood in Ngreneng Karst Window. This study aimed to analyze the mechanism of this flood. The results of the analysis showed that it was caused by water filling up the conduit passage in the entire Bribin-Baron underground river system. The flow of the conduit pushed the diffuse flow into the surface fast, and the water that came out of Ngreneng Karst Window was thereby clear. The inundation lasted for ten days and submerged up to 26.4 ha of the study area.

scholarly journals Banjir Airtanah Akibat Siklon Tropis Cempaka di Karst Window Ngreneng, Kawasan Karst Gunungsewu, Indonesia

2018 ◽  
Author(s):  
Ahmad Cahyadi ◽  
Tjahyo Nugroho Adji ◽  
Indra Agus Riyanto ◽  
Hendy Fatchurohman ◽  
Eko Haryono ◽  
...  
Keyword(s):  
Tropical Cyclone ◽  
Indian Ocean ◽  
Extreme Rainfall ◽  
River System ◽  
Karst Area ◽  
Diffuse Flow ◽  
Central Java ◽  
The Indian Ocean ◽  
Water Filling ◽  
Underground River

Tropical Cyclone Cempaka occurred on November 27, 2017 in the Indian Ocean, just south of Central Java. This incident induced high rainfall leading to flash floods in the southern part of Central Java, including Gunungsewu Karst Area. The highest rainfall recorded on November 28, 2017, in this area was 239 mm/day (Automatic Rainfall Recorder/ARR Station in Pindul Cave) and 341 mm/day (ARR Station in Tepus). The extreme rainfall also caused groundwater flood in Ngreneng Karst Window. This study aimed to analyze the mechanism of this flood. The results of the analysis showed that it was caused by water filling up the conduit passage in the entire Bribin-Baron underground river system. The flow of the conduit pushed the diffuse flow into the surface fast, and the water that came out of Ngreneng Karst Window was thereby clear. The inundation lasted for ten days and submerged up to 26.4 ha of the study area.

scholarly journals Master Recession Curve (MRC) analysis to characterize karst aquifers of several springs in the north side of the Karangbolong (Gombong) karst area

2020 ◽  
Vol 202 ◽  
pp. 04002
Author(s):  
Aulia Ika Rahmawati ◽  
Alpine Prima Priambada ◽  
Muhammad Qodri Al-Ghozali ◽  
Danang Riza Fauzi ◽  
Tjahyo Nugroho Adji ◽  
...  
Keyword(s):  
Karst Aquifer ◽  
Base Flow ◽  
Karst Area ◽  
Karst Aquifers ◽  
The North ◽  
North Side ◽  
Recession Curve ◽  
Flood Hydrograph ◽  
Master Recession Curve ◽  
Discharge Regime

Karst aquifers have triple porosity (diffuse, fissure, and conduit) which makes their characterization difficult, and often requires a combination of particular methods and investigation over a long period. The purpose of this study is to analyse the components of the flood hydrograph and create a master recession curve (MRC) in karst aquifers that recharge several springs on the north side of the Karangbolong Karst Area (Gombong). The springs studied include Kalisirah, Jumbleng, and Kalikarak springs. The data used are time-series discharges recorded every 15 minutes from November 2018 to March 2020. Furthermore, the reconstruction of the flow regime for MRC is carried out with the help of RC 4.0 software, which is at the same time able to define the level of karst aquifer development. The results showed that Kalisirah and Kalikarak Springs have a complex discharge regime with a degree of karstification in class 8, while Jumbleng Springs in class 5. Analysis of the components of the flood hydrograph reinforces the results of the calculation of the karstification degree. The time to the peak (Tlag) of the Kalisirah and Kalikarak Springs is relatively fast (1.94 and 1.44 hours), which indicates that conduit flow has developed, while Jumbleng spring has a longer Tlag of 2.69 hours. Calculation of time to base flow (Tb) both manually (by flood events analysis) and automatically (by MRC) shows that Kalikarak Springs has the longest time with an average of about 31 hours which reflects that karst aquifers which contribute to it are still quite good in storing groundwater, while Jumbleng spring has the fastest Tb value with an average of 17.25 hours which reflects the shortest release of water storage compared to the other two springs.

A Radiocarbon-dated Collared Urn from Oban

2001 ◽  
Vol 23 (2) ◽  
pp. 105-118
Author(s):  
CHRISTOPHER LOWE ◽  
ANN MacSWEEN ◽  
KATHLEEN McSWEENEY
Keyword(s):  
The North ◽  
North Side ◽  
Funerary Ritual

A collared urn was found during the course of a watching-brief on the raised beach on the north side of Oban bay. Post-excavation analysis has succeeded in throwing some further light on the chronology of this type of urn and possibly on some elements of the funerary ritual associated with its burial. The same watching-brief also revealed the site of a truncated pit of medieval date, filled with fire-cracked stones.

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