scholarly journals Analisis MRC untuk Karakterisasi Akuifer Karst di Mataair Mudal, Kabupaten Kuloprogo

2020 ◽  
Vol 33 (2) ◽  
Author(s):  
Afid Nurkholis ◽  
Tjahyo Nugroho Adji ◽  
Eko Haryono ◽  
Ahmad Cahyadi ◽  
Wisnu Agung Waskito ◽  
...  

Akuifer karst memiliki triple porosity yang membuat karakterisasinya sulit dilakukan. Tujuan dari penelitian ini adalah menganalisis komponen hidrograf banjir dan membuat Master Recession Curve (MRC) pada akuifer karst yang mengimbuh Mataair Mudal. Data yang digunakan adalah debit aliran dan curah hujan yang tercatat setiap 30 menit pada November 2017 hingga Mei 2018 (6 bulan). Hasil penelitian menunjukkan bahwa Mataair Mudal memiliki complex discharge regime dengan derajat karstifikasi pada kelas 5,5. Analisis komponen hidrograf banjir menguatkan hasil perhitungan derajat karstifikasi. Waktu menuju puncak banjir (Tlag) yang tergolong cepat (2,5 jam) menunjukkan telah adanya aliran conduit. Perhitungan waktu menuju aliran dasar (Tb) baik secara manual (hidrograf banjir) maupun automatis (MRC) memiliki rerata sekitar 40 jam yang mencerminkan bahwa akuifer karst yang mengimbunya masih baik dalam menyimpan airtanah. Secara keseluruhan, akuifer karst di Mataair Mudal masih didominasi oleh retakan bertipe diffuse, meskipun sudah memiliki retakan bertipe conduit yang cukup berkembangThe objective of this research was to analyze the nature of the flood hydrograph components and create a Master Recession Curve (MRC) to estimate the degree of karstification in Mudal Spring. Discharge and rainfall data were recorded every 30 minutes at time intervals between November 2017 and May 2018. The results show that Mudal Spring has a complex discharge regime with a karstification degree in the class of 5.5. Meanwhile, the time to peak flood (Tlag) which is relatively fast (2.5 hours) shows the existence of conduit flow in the flood event. Calculation of time to baseflow (Tb) has an average of 40 hours which reflects that the karst aquifer was still good in storing groundwater. Overall, karst aquifers in Mudal Spring are still dominated by diffuse type voids, although they already have conduit type voids that are quite developed.

2020 ◽  
Vol 202 ◽  
pp. 04002
Author(s):  
Aulia Ika Rahmawati ◽  
Alpine Prima Priambada ◽  
Muhammad Qodri Al-Ghozali ◽  
Danang Riza Fauzi ◽  
Tjahyo Nugroho Adji ◽  
...  

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.


2022 ◽  
Author(s):  
Fatemeh Geravand ◽  
Seiyed Mossa Hosseini ◽  
Mehran Maghsoudi ◽  
Mojtaba Yamani

Abstract Karst groundwater resources in the Zagros Mountains are vital for supplying of different demands in the region which need to sustainable management and protection. Quantitative and qualitative characterization of karst aquifers in this region were understudied due to lack of site-specific logging-data and speleological investigations. In this study, a state-of-the-art of the statistical methods developed to characterize karst aquifer based on analyses of the spring recession hydrograph and spring water quality are presented. These methods including Manging’s method for classification of karst aquifers, relationships of precipitation and discharge data, groundwater quality index (GQI), hydrochemical diagrams (Piper, Durov and Gibbs), and Saturation index (SI), Chloro-Alkaline indices (CAI). 42 major karst springs mainly located in folded part of Zagros region (western Iran) are selected for application of the reviewed methods. Results indicated that the saturated zone exerts almost main control over the discharge of 76% of the studied springs. The base-flow contributes as between 80.0% to 100% of total water storage in the study aquifers. 78.5% of the studied aquifers have a high karstification degree. An insignificant lag-time is observed between the precipitation on the karst basin and spring discharge. The hydrochemical diagrams show that the waters are dominated by HCO3 and Ca and the majority of the waters are alkaline, with originate from silicate minerals weathering. Such repeatable methods adopted in this study can provide crucial information of the karst aquifers, especially those suffer scarcity of aquifer hydrodynamic data.


Author(s):  
Wei Chang ◽  
Junwei Wan ◽  
Jiahua Tan ◽  
Zongxing Wang ◽  
Cong Jiang ◽  
...  

It is a challenge to describe the hydrogeological characteristics of karst aquifers due to the complex structure with extremely high heterogeneity. As the response of karst aquifers to rainfall events, spring discharge variations after precipitation can be used to identify the internal structure of karst systems. In this study, responses of spring discharge to different kinds of precipitations are investigated by continuously monitoring precipitation and karst spring flow at a single-conduit karst aquifer in western Hunan province, China. Recession curves were used to analyze hydrodynamic behaviors and separate recession stages. The results show that the shape of the recession curve was changed under different rainfall conditions. Recession processes can be divided in to three recession stages under heavy rain conditions due to water drainage mainly from conduits, fracture, and matrix at each stage, but only one recession stage representing drainage mainly from matrix in the case of light rain. With the change in amount and intensity of precipitation, the calculated recession coefficient at each stage changes in an order of magnitude. The influence of precipitation on the recharge coefficient and the discharge composition at each recession are discussed, and then the conceptual model diagram of water filling and releasing in the single-conduit karst aquifers is concluded. The findings provide more insight understand on hydraulic behaviors of karst spring under different types of rainfall events and provide support for water resource management in karst regions.


2014 ◽  
Vol 18 (2) ◽  
pp. 803-817 ◽  
Author(s):  
V. Allocca ◽  
F. Manna ◽  
P. De Vita

Abstract. To assess the mean annual groundwater recharge of the karst aquifers in the southern Apennines (Italy), the estimation of the mean annual groundwater recharge coefficient (AGRC) was conducted by means of an integrated approach based on hydrogeological, hydrological, geomorphological, land use and soil cover analyses. Starting from the hydrological budget equation, the coefficient was conceived as the ratio between the net groundwater outflow and the precipitation minus actual evapotranspiration (P − ETR) for a karst aquifer. A large part of the southern Apennines, which is covered by a meteorological network containing 40 principal karst aquifers, was studied. Using precipitation and air temperature time series gathered through monitoring stations operating in the period 1926–2012, the mean annual P − ETR was estimated, and its distribution was modelled at a regional scale by considering the orographic barrier and rain shadow effects of the Apennine chain, as well as the altitudinal control. Four sample karst aquifers with available long spring discharge time series were identified for estimating the AGRC. The resulting values were correlated with other parameters that control groundwater recharge, such as the extension of outcropping karst rocks, morphological settings, land use and covering soil type. A multiple linear regression between the AGRC, lithology and the summit plateau and endorheic areas was found. This empirical model was used to assess the AGRC and mean annual groundwater recharge in other regional karst aquifers. The coefficient was calculated as ranging between 50 and 79%, thus being comparable with other similar estimations carried out for karst aquifers of European and Mediterranean countries. The mean annual groundwater recharge for karst aquifers of the southern Apennines was assessed by these characterizations and validated by a comparison with available groundwater outflow measurements. These results represent a deeper understanding of an aspect of groundwater hydrology in karst aquifers which is fundamental for the formulation of appropriate management models of groundwater resources at a regional scale, also taking into account mitigation strategies for climate change impacts. Finally, the proposed hydrological characterizations are also supposed to be useful for the assessment of mean annual runoff over carbonate mountains, which is another important topic concerning water management in the southern Apennines.


2012 ◽  
Vol 60 (1) ◽  
pp. 3-15 ◽  
Author(s):  
Miloš Gregor ◽  
Peter Malík

Construction of Master Recession Curve Using Genetic Algorithms The article describes a new methodology of using genetic algorithms to assemble a natural time series of discharge recession, from which a master recession curve can be interpreted both for streams and for springs. Presented approach can avoid obstacles such as limited time-series datasets, incomplete recessions or too many recessionary segments in many recession series, different time intervals of observations (daily or weekly frequencies). Short time-series intervals, imprecise or mistaken measurements and different types of datasets (averaged or directly measured data) are taken into account as well. Even rough measurements of discharges with inaccurate sensing range can be analysed, if sufficiently long observation is available. Complicated hydrograph shapes in the case of e.g. karstic springs (often caused by combination of laminar and turbulent discharge sub-regimes due to karst network settings) can be processed as well. Subsequent construction of master recession curve is much easier an offers better conditions for its interpretation. Presented algorithm was already implemented to a programme solution, completed on the user form.


2021 ◽  
Author(s):  
Luka Vucinic ◽  
David O'Connell ◽  
Donata Dubber ◽  
Patrice Behan ◽  
Quentin Crowley ◽  
...  

<p>Lowland karst aquifers in Ireland are extremely complex to understand and are considered to be highly vulnerable to pollution (e.g. low-lying karst catchments exhibit a lot of surface water – groundwater interactions which makes them very susceptible to direct contamination). These aquifers are impacted by multiple contamination sources on land (in particular, rural sources from agriculture and on-site domestic wastewater effluent) which makes their protection and management challenging. Human wastewater effluent is identified as significant threat to groundwater quality in such lowland Irish karst environments, since approximately one-third of the population in Ireland is relying on decentralized wastewater treatment systems for the treatment of domestic wastewater. However, it is difficult to distinguish between human wastewater effluent and agricultural pollution impacts on karst aquifers using only traditional water quality parameters or any single environmental tracing method. Hence, the impact of microbial and chemical contaminants of human wastewater origin on groundwater quality must be assessed using a multiple-tracer approach, ideally targeting source-specific tracers. This paper presents an overview of the results obtained during the research conducted throughout the last several years at nine karst catchments in Ireland using a range of methodologies in order to determine and quantify domestic wastewater pollution impacts on karst springs. Microbial pollution was assessed using flow cytometric fingerprinting and faecal indicator bacteria, while chemical pollution impact assessment included the analysis of fluorescent whitening compounds (FWCs; well-known indicators of human contamination since their origin is mostly from laundry detergents), specific anion ratio signatures (Cl/Br), quantification and identification of microplastic particles using Fourier-transform infrared spectroscopy (FTIR), and faecal sterol and stanol profiles and ratios. A thorough analysis of the results obtained using a multiple-tracer approach has been conducted and methodologies have been evaluated in terms of applicability and sensitivity in a range of different karst catchments. The ability of these methodologies and techniques to determine and quantify human faecal pollution impacts on karst springs will be discussed. The results show a significant correlation between microplastic particle counts and detected FWCs signals at different springs, which helps to understand the contribution of household-derived contaminants to this environmental problem. Moreover, our results indicate that faecal sterols and stanols can be useful faecal source tracking method in karst aquifer systems despite the fact that concentrations of sterols and stanols of interest were usually low which makes the interpretation of results challenging.</p>


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