scholarly journals Groundwater Flow Modeling at Sejorong Watershed, Sumbawa,West Nusa Tenggara, Indonesia

2019 ◽  
Vol 4 (2) ◽  
pp. 43
Author(s):  
Adelide Asriati Sekar Rianda ◽  
Doni Prakasa Eka Putra ◽  
Wahyu Wilopo

Batu Hijau mine pit is known as one of the largest copper pit mine in Nusa Tenggara Barat, Indonesia. Similiar as other copper mine pits in Indonesia, This site also faces acid mine water (AMD) problem. Based on the mine management plan, the AMD generated from this pit is being collected into Santong ponds in the southwest of the pit located in the upstrean area if Sejorong watershed. By the next decade, Batu Hijau mine will be in the closure mine period and it is important to understand the probable movement of AMD under the Santong ponds whether the AMD leaked to groundwater or not. This research aims to develop a numerical model of groundwater flow and predict the movement of AMD by applying particle tracking method. Secondary and primary data of geology, hydrology, and hydrogeology. Also, groundwater pumpage discharge information was collected and analysed to develop hydrogeological conceptual model and the numerical model. The conceptual model of hydrogeological system in the research area is known to be built on unconfined aquifer system from a combination of weathered and fractured volcanic rocks in the upstream to middle part of watershed and majorly by alluvial and coastal deposits in the downstream area. The thickness of aquifer is vary between 20 to about 300 m and divide into 5 layers in the numerical model, with hydraulic conductivity ranges between 5 to 100 m/day and groundwater recharge is vary between 180 to 700 mm/year from downstream to upstream of watershed. Groundwater flow boundaries in the Sejorong watershed are mainly controlled by topographical feature as water divide boundaries and the existing of Sejorong parennial rivers in the middle of this watershed. Steady state particle tracking results from the numerical groundwater flow model show AMD from Santong ponds may migrate in groundwater only to a distance of about 500 m to the downstream and therefore it is unlikely that AMD seepages from Santong pond may contaminate water in the production wells

2021 ◽  
Vol 926 (1) ◽  
pp. 012078
Author(s):  
D L Setyaningsih ◽  
K D Setyawan ◽  
D P E Putra ◽  
Salahuddin

Abstract Randublatung groundwater basin is one of the groundwaters basins with massive utilization of groundwater pumping. However, the knowledge of the comprehensive hydrogeological system in this groundwater basin is limited, so this research aims to determine a comprehensive hydrogeological conceptual model of the Randublatung groundwater basin. The methodology was conducted by collecting secondary and primary data of deep and shallow wells to evaluate boundaries of pattern and direction of groundwater flow and develop the aquifer system’s geometry. The result shows that the groundwater flow boundaries are Grogol River in the west, Wado River in the East, Bengawan Solo river in the South as a river boundary, and Rembang Mountains in the North as a constant head boundary. Therefore, groundwater flows from the hills area to the Bengawan Solo River and the north as the river’s flow. Based on the log bor evaluation, the aquifer system of the study area consist of an unconfined aquifer with a maximum thickness of 20 m and three layers of confined aquifers with thickness vary between 8 to 60 m. the hydraulic conductivity of the aquifers depends on the aquifer’s lithology range from sand, gravel, limestone, and sandstone. This hydrogeological conceptual model provides essential information for numerical groundwater models in the middle of the Randublatung groundwater basin.


2020 ◽  
Vol 1 (1) ◽  
pp. 7-11
Author(s):  
Avellyn Shintya Sari ◽  
Sari Bahagiarti K ◽  
Suharsono Suharsono ◽  
C Prasetyadi

The hydrogeological condition of a region is determined by the type of lithology, morphology, and subsurface conditions where the condition is very helpful in the study of groundwater exploration. Especially when we encounter interesting geological conditions when the groundwater exploration in the karst area in which volcanic rocks are resulting from the activities of the active volcano in the past. Groundwater exploration at Ponjong area and surrounding does have its special characteristics, because it has 2 different rock characteristics where the northern part of the research area in the form of a karst area (limestone of Wonosari Formation) while the southern part is an area of ancient volcanoes with dominant volcanic rocks from Wuni Formation, As for the research on the above and subsurface research area where the research is conducted based on surface geology mapping, geoelectric data collection, and groundwater sampling. Geological mapping includes geomorphological data, stratigraphy, and geological structure. The aquifer system of the research area can be divided into two systems, inter-grain aquifer systems, and fracture aquifer systems. Overall quality groundwater in the research area is quite good. Ponjong District there are mining activities that have resulted in changes in the land use system in the area. This can cause changes in the water surplus in the area due to the changing catchment area.


Author(s):  
Riccardo Armellini ◽  
Elena Baldini ◽  
Dario Del Seppia ◽  
Fabrizio Franceschini ◽  
Natacha Gori ◽  
...  

This work provides a groundwater flow and transport model of trichlorethylene and tetrachlorethylene contamination in the Cecina’s coastal aquifer. The contamination analysis, with source located in the Poggio Gagliardo area (Montescudaio, Pisa), was necessary to optimize the groundwater monitoring and remediation design. The work was carried out in two phases: • design of a conceptual model of the aquifer using GIS analysis of many stratigraphic, chemical and hydrogeological data, collected from 2004 to 2012 in six aqueduct wells; • implementation of a groundwater flow and transport numerical model using the MODFLOW 88/96 and MT3D code and the graphical user interface GroundWaterVistas 5. The conceptual model hypothesizes a multilayer aquifer in the coastal plain extended to the sandy-clay hills, recharged by rainfall and by the Cecina River. The aquifer shows important hydrodynamic features affecting both the contamination spreading, due to the presence of a perched and heavily polluted layer separate from the underlying productive aquifer, and the hydrological balance, due to a thick separation layer that limits exchanges between the river and the second groundwater aquifer. The numerical model, built using increasingly complex versions of the initial conceptual model, has been calibrated using monitoring surveys conducted by the Environmental Protection Agency of Regione Toscana (ARPAT), in order to obtain possible forecast scenarios based on the minimum and maximum flow periods, and it is currently used as a tool for decision support regarding the reclamation and/or protection of the aquifer. Future developments will regard the implementation of the multilayer transport model, based on a new survey, and the final coupling with the regional hydrological model named MOBIDIC.


2019 ◽  
Vol 24 (2) ◽  
pp. 30-38
Author(s):  
Rita Bhandari ◽  
Dinesh Pathak

 Models are simplification of reality to investigate certain phenomena or to predict future behavior and always tries to generate scenario that is close to the real condition. Groundwater flow models are computer models generated through using established flow equations that simulate and predict aquifer conditions. The result of groundwater modeling is used for groundwater management and remediation. In the present study, hydrostratigraphic units were identified through interpreting the lithological logs of the drilled wells then fence diagram was prepared with three major aquifer horizons, namely unconfined, shallow confined and deep confined aquifers. In addition, hydrogeologic data were integrated to develop a conceptual hydrogeologic model of the aquifer system of the Chitwan Dun valley, which was the basis for the development of the numerical model. The aquifer system was modeled numerically using MODFLOW-2005 numerical modeling, which was further calibrated and an acceptable numerical model was obtained which showed different flow direction in each aquifer layer. The model was validated by comparing the observed and simulated heads. The result shows that in each of the aquifer layers, the general flow direction is towards west and south-west.


Author(s):  
Giovanna De Filippis ◽  
Mauro Giudici ◽  
Stefano Margiotta ◽  
Fiorella Mazzone ◽  
Sergio Negrini ◽  
...  

Water resources represented by coastal aquifers are very important for regions characterized by a relevant request of freshwater, but limited rainfall, lack of surface water bodies and intrusion of the seawater through the sediments which host groundwater. Therefore some coastal areas, like the Salento peninsula (southern Italy), are subjected to the risk of desertification and a proper management of groundwater resources requires tools to analyze and predict the water balance and the evolution of the physical system in response to human activities (e.g., ground water withdrawals) and climatic factors. The Salento peninsula is a typical Mediterranean basin, where the main water resource is the aquifer hosted in Cretaceous carbonatic rocks (Calcare di Altamura, Altamura limestone): this is a fractured and karst aquifer, with a poor recharge and complex relationships with the sea. In order to develop a tool to assess the water balance at regional scale for the considered aquifer system, a groundwater flow model was developed by Giudici et al. (2012a); it is based on a conceptual model obtained from a reconstruction of the hydrostratigraphic architecture of the region, which includes the main aquifer and the overlaying rocks characterized by low permeability which can host local and relatively thin aquifers. In this paper that work is updated, by improving the reconstruction of the hydraulic head and of the conceptual model, above all in those areas that the previous model evidenced as critical for the absence of fresh water along the whole aquifer thickness. Moreover, since the estimate of some model’s input parameters is affected by high uncertainty, a sensitivity analysis is performed to evaluate the effects of this uncertainty on the model’s results.


2018 ◽  
Vol 7 (4) ◽  
pp. 191
Author(s):  
Sherwan Sh. Qurtas

Recharge estimation accurately is crucial to proper groundwater resource management, for the groundwater is dynamic and replenished natural resource. Usually recharge estimation depends on the; the water balance, water levels, and precipitation. This paper is studying the south-middle part of Erbil basin, with the majority of Quaternary sediments, the unconfined aquifer system is dominant, and the unsaturated zone is ranging from 15 to 50 meters, which groundwater levels response is moderate. The purpose of this study is quantification the natural recharge from precipitation. The water table fluctuation method is applied; using groundwater levels data of selected monitoring wells, neighboring meteorological station of the wells, and the specific yield of the aquifers. This method is widely used for its simplicity, scientific, realistic, and direct measurement. The accuracy depends on the how much the determination of specific yield is accurate, accuracy of the data, and the extrapolations of recession of groundwater levels curves of no rain periods. The normal annual precipitation there is 420 mm, the average recharge is 89 mm, and the average specific yield is around 0.03. The data of one water year of 2009 and 2010 has taken for some technical and accuracy reasons.


2017 ◽  
Vol 11 (1) ◽  
pp. 69-96
Author(s):  
Siti Yuliaty Chansa Arfah ◽  
Harianto . ◽  
Suharno .

Penelitian ini bertujuan untuk mengkaji daya saing komoditi kakao di Sulawesi Tengah dan melihat peran pemerintah dalam meningkatkan daya saing komoditi kakao. Data primer berasal dari observasi, wawancara dan kuesioner, sementara data sekunder berasal dari instansi terkait. Metode analisis menggunakan Policy Analysis Matrix (PAM) dan analisis sensitivitas. Penelitian ini menemukan bahwa nilai PCR Kabupaten Parigi Moutong 0,589 dan Kabupaten Sigi 0,396. Sedangkan nilai DRC Kabupaten Parigi Moutong 0,387 dan Kabupaten Sigi 0,319. Hal tersebut mengindikasikan bahwa usahatani komoditi kakao di Sulawesi Tengah memiliki daya saing, namun tidak menguntungkan secara ekonomi karena Sulawesi Tengah menghasilkan biji kakao yang tidak difermentasi akibatnya petani menerima harga rendah. Berdasarkan hasil analisis, pemerintah belum memberikan proteksi terhadap harga biji kakao dalam negeri melalui harga referensi biji kakao sehingga harga biji kakao didaerah penelitian masih tergolong rendah jika dibandingkan dengan harga di pasar internasional. Sementara terhadap input, pemerintah telah memberikan kebijakan subsidi kepada petani, namun implementasinya masih perlu perbaikan terutama terkait penyaluran dan pengelolaan bantuan agar merata. Kajian ini merekomendasikan masih diperlukan kebijakan pemerintah baik terhadap input maupun output untuk meningkatkan produktivitas, menurunkan biaya produksi dan menaikkan harga jual biji kakao, sehingga dapat meningkatkan daya saing biji kakao. The purpose of this study is to assess the competitiveness of cocoa in Central Sulawesi and to investigate the role of government in improving the competitiveness of cocoa. The primary data were generated through observation, interviews and some questionnaires. The secondary data were obtained from the agency or the institution related to the research. This study uses the Policy Analysis Matrix (PAM) and sensitivity analysis. The study found that the PCR value for Parigi Moutong district was 0.589 and Sigi district was 0.396. While, the DRC value for Parigi Moutong district was 0.387 and Sigi district was 0.319. This indicates that cocoa beans farming in Central Sulawesi has competitiveness, but not economically beneficial because Central Sulawesi produces unfermented cocoa beans consequently farmers receive low prices. Based on the results of the government's impact on output analysis, the government did not provide protection for domestic cocoa seed prices through the reference price of cocoa beans, consequently the price of domestic cocoa beans, particularly in the research area, was relatively low compared to the price of cocoa beans at the international market. Seen from the government policy on inputs, the government have provided subsidies to farmers but they need to improve the distribution and management of aid to be evenly distributed. It is necessary to set up good government policy on inputs and outputs in order to increase cocoa seed productivity, decrease production cost and increase the price which simultaneously can improve its competitiveness in the research location.


Author(s):  
John P. Masterson ◽  
Carl S. Carlson ◽  
Donald A. Walter ◽  
Gardner C. Other contributing authors: Bent ◽  
Andrew J. Massey

Sign in / Sign up

Export Citation Format

Share Document