scholarly journals Karakteristik Fluktuasi Permukaan Air Tanah Pada Akuifer Tidak Tertekan di Kelurahan Cibabat, Kecamatan Cimahi Utara, Kota Cimahi

2017 ◽  
Vol 8 (3) ◽  
pp. 117
Author(s):  
Aditya Priyo Utomo
Keyword(s):  
Hydraulic Conductivity ◽  
Groundwater Level ◽  
Pumping Test ◽  
Research Area ◽  
Unconfined Aquifer ◽  
Shallow Aquifer ◽  
Recharge Area ◽  
Groundwater Level Fluctuations ◽  
Level Measurement ◽  
Administrative Area

ABSTRAKCibabat berada dalam wilayah administratif Kecamatan Cimahi Utara, yang pada tahun 2014 memiliki tingkatpertumbuhan penduduk sebesar 25% per tahun. Peningkatan jumlah penduduk berdampak terhadap perubahantataguna lahan, yang berimbas pada berkurangnya area resapan air tanah dan meningkatnya kebutuhan pendudukakan air tanah yang mengakibatkan terjadinya fluktuasi air tanah pada daerah tersebut. Penelitian ini dilakukan untukmengetahui perbedaan fluktuasi permukaan air tanah pada daerah Cibabat, yang dipengaruhi iklim, keadaan geologi,dan kepadatan penduduk. Metode yang digunakan dalam penelitian ini di antaranya adalah geolistrik untuk intepretasigelogi bawah permukaan, pengukuran permukaan air tanah dan uji pemompaan untuk mengetahui tingkat fluktuasimuka air tanah dan besaran transmisivitas dan konduktivitas hidroliknya. Dari hasil penelitian diketahui bahwaakuifer dangkal pada daerah Cibabat merupakan akuifer bebas, dengan tingkat transmisivitas rendah yakni 0,08 / haridan konduktivitas hidrolik sebesar 1,3 10-9. Hasil pemantauan muka air tanah menunjukan fluktuasi muka air tanahyang beragam dengan tingkat penurunan terdalam berada pada bagian utara daerah penelitian yang mencapai 4,4mpada musim kemarau. Dalam jangka waktu panjang, dengan jumlah kepadatan penduduk yang terus bertambah akanmengakibatkan rusaknya keseimbangan air tanah pada daerah tersebut.Kata kunci: Cibabat, fluktuasi muka air tanah, transmisivitasABSTRACTCibabat located in the administrative area of of Cimahi Utara Distrct, which in 2014 had a population growth rateof 25% per year. The increase in population resulted in a change of land use, which impact on the reduction ofgroundwater recharge area and the increas in needs of the population will be groundwater. This study was conductedto determine differences in the groundwater level fluctuations in Cibabat area, which influenced the climate, geologicalconditions and population density. The method used in this study include the geoelectric to interpret geologicalsubsurface, groundwater level measurement and pumping test to determine the level of groundwater level fluctuationsand the amount of transmissivity and hydraulic conductivity. The result showed that the shallow aquifer in Cibabatis unconfined aquifer, with a low transmissivity level that is 0,08 / day and the hydraulic conductivity of 1,3 10-9.Monitoring results showed groundwater level fluctuations that vary with the level of the deepest decline was in thenorthern part of the research area that reached 4,4m in the dry season. In the longer term, this situation will lead tothe destruction of the groundnwater balance in the area.Keywords: Cibabat groundwater, groundwater level fluctuations, transmissivity

scholarly journals Using Geoelectric Soundings for Estimation of Hydraulic Characteristics of Aquifers in the Coastal Area of Lagos, Southwestern Nigeria

2014 ◽  
Vol 11 ◽  
pp. 30-39 ◽  
Author(s):  
J.O. Fatoba ◽  
S.D. Omolayo ◽  
E.O. Adigun
Keyword(s):  
Hydraulic Conductivity ◽  
Saline Water ◽  
Pumping Test ◽  
Shallow Aquifer ◽  
High Porosity ◽  
Hydraulic Characteristics ◽  
Southwestern Nigeria ◽  
Geoelectric Section ◽  
Current Electrode ◽  
Transverse Resistance

Electrical resistivity investigation was carried out at Ibeju Lekki, Southwestern Nigeria. The thrust of this study is to determine the geoelectrical parameters of the shallow aquifer and estimate the hydraulic characteristics of this aquifer unit from the surface geophysics. The area falls within the Dahomey basin of the Nigeria sedimentary terrain. Twenty-one VES were conducted using Shlumberger array with a maximum half current electrode (AB/2) of 100 m giving total spread of 200 m. Data were interpreted using partial curve matching technique and assisted 1-D forward modeling with WINRESIST software. The qualitative interpretation revealed KQ curves (ρ1 < ρ2 > ρ3 > ρ4) and KH curve (ρ1 < ρ2 > ρ3 < ρ4). The geoelectric section generated from the results of the VES revealed a four geo-electric layers; these include topsoil with resistivity ranging from 213-5404 Ωm, dry sand with resistivity values vary from 301to 17178 Ωm, saturated sand with resistivity varying from 110 to1724 Ωm and sand (saline water content) with resistivity values of between 8 and 97 Ωm. The major aquifer in the area occurs at the third geoelectric layer. The depth to this aquifer is of between 0.7m and 6.0m and the layer thickness is between 0.2 m and 19.9 m. The hydraulic characteristics of the aquifer estimated from the geoelectric parameters reveal that the aquifer has porosity values of between 29.4 % and 57.7 %, protective capacities of between 0.00013 and 0.015 mhos, transverse resistance ranges from 345-18502 Ωm2, transmissivity values vary from 13 to 310 m2/day and hydraulic conductivity ranges from 0.8-65 m/day. The results show that the aquifer is characterized by high porosity and low protective capacities of overburden layers indicating that it is highly vulnerable to surface contamination. It has high transverse resistance, high transmissivity, and high hydraulic conductivity indicating that the aquifer can transmit water at higher rate and sustain the need of the community. This study has demonstrated the efficacy of surface geophysics in estimating hydraulic characteristics of an aquifer where pumping test data are not available and also to determine its vulnerability to surface contaminants.

Hydrologic Characteristics and Response of Fractured Till and Clay Confining a Shallow Aquifer

1975 ◽  
Vol 12 (1) ◽  
pp. 23-43 ◽  
Author(s):  
G. E. Grisak ◽  
J. A. Cherry
Keyword(s):  
Hydraulic Conductivity ◽  
Fractured Rock ◽  
Nuclear Research ◽  
Pumping Test ◽  
Shallow Aquifer ◽  
Ratio Method ◽  
Clay Loam ◽  
Specific Storage ◽  
Groundwater Movement ◽  
Lacustrine Clay

Fractures in glacial till and glaciolacustrine clay were observed in excavations up to 20 ft (6.1 m) in depth and in drill cores at the Whiteshell Nuclear Research Establishment (WNRE) in southeastern Manitoba. The fractures are characteristically coated with carbonate and oxide precipitates, which indicate groundwater movement through the fractures. The fractures impart an effective bulk hydraulic conductivity to the clay–loam till and lacustrine clay, as evidenced by tritium tracer experiments and piezometer responses in the till and clay to pumping of an underlying sandy aquifer.The intergranular hydraulic conductivity of clay–loam till and glaciolacustrine clay in the Interior Plains, as determined from laboratory consolidation test data, is in the range of 2 × 10−10 to 9 × 10−11 ft s−1 (6 × 10−9 to 2.7 × 10−9 cm s−1). The bulk hydraulic conductivity of the fractured clay–loam till at WNRE, as determined from finite-element mathematical modeling, is about 6 × 10−9 ft s−1 (1.8 × 10−7 cm s−1). The model value represents the effective hydraulic conductivity imparted to the till by the fractures.Seven pumping tests, ranging in duration from 8.75 to 120 h were conducted on the sandy aquifer and drawdown data in the aquifer were analyzed to obtain the hydraulic conductivity and storativity of the aquifers.A 32 day pumping test on the aquifer showed that many of the piezometers in the till and clay respond quickly and strongly to the aquifer drawdown, while others show no noticeable response. The responding piezometers intersect open fractures whereas the others do not. Analysis of the piezometer drawdowns during the long-term pumping test using the Neuman and Witherspoon ‘ratio’ method indicates that the rapid piezometer drawdowns in the confining layers can be accounted for by assigning specific storativity values in the range of 1 × 10−5 to 5 × 10−6 ft−1 (3 × 10−5 to 1.5 × 10−5 m−1) to the clay–loam till and lacustrine clay. These values are typical of fractured rock. If intergranular specific storage values are used, the calculated piezometer drawdowns are very small or negligible.

scholarly journals Studi Kerentanan Air Tanah Terhadap Kontaminan Menggunakan Metode Drastic di Kota Pekalongan

Teknik ◽  
2016 ◽  
Vol 37 (1) ◽  
pp. 26
Author(s):  
Thomas Triadi Putranto ◽  
Dian Agus Widiarso ◽  
Fatir Yuslihanu
Keyword(s):  
Hydraulic Conductivity ◽  
Total Population ◽  
Shallow Groundwater ◽  
Groundwater Vulnerability ◽  
Unconfined Aquifer ◽  
Shallow Aquifer ◽  
The North ◽  
Drastic Method ◽  
Dug Wells ◽  
Aquifer Type

Kota Pekalongan berada di Pulau Jawa bagian Utara. Jumlah penduduk kota pekalongan setiap tahunnya mengalami peningkatan. Tahun 2008 jumlah penduduk Kota Pekalongan sebanyak 271.990 jiwa kemudian menjadi 290.347 di Tahun 2012.. Untuk memenuhi kebutuhan air, peduduk Kota Pekalongan menggunakan sumur gali yang menyadap air dari akuifer bebas atau akuifer dangkal. Air tanah bebas sangat rentan terhadap pencemaran akibat pengaruh letaknya yang dangkal dan aktivitas manusia. Oleh sebab itu diperlukan suatu kajian mengenai kerentanan air tanah terhadap kontaminan. Analisis dilakukan denganmenggunakan metode DRASTIC. Metode ini merupakan metode pombobotan berdasarkan beberapa parameter, yaitu: kedalaman muka air tanah (D), jumlah area recharge (R), litologi akuifer (A), jenis media tanah (S), topografi (T), jenis media zona tak jenuh air (I), dan konduktivitas hidrolika (C). Berdasarkan hasil analisis DRASTIC, terdapat tiga tingkat kerentanan yaitu: daerah tingkat kerentanan sedang dengan nilai DRASTIC Indeks (DI) 101-140, daerah tingkat kerentanan tinggi dengan nilai DI 141-180, dan daerah tingkat kerentanan sangat tinggi dengan nilai DI >180.[An Assessment of Groundwater Vulnerability of Contaminant Using DRASTIC Method in Pekalongan City] Pekalongan city which located on the north of Java Island is growing fast, in particular in the population growth. In 2008, total population in Pekalongan city was 271.990 inhabitants increased then up to 290.347 inhabitants in 2012. To fill the water necessary, people in Pekalongan city are using dug wells which are abstracted groundwater from the unconfined aquifer or shallow aquifer. Shallow groundwater can be vulnerabe which are influenced by surface and human activities. Thus, it requires an assessment of the groundwater vulnerability and risk of contaminant. It was analyzed by DRASTIC method. The DRASTIC method is applied by using weighted of some parameters, i.e.: groundwater Depth (D), amount of Recharge (R), Aquifer type (A), Soil type (S), topography (T), Impact of unsatuated zone (I), and hydraulic Conductivity (C). DRASTIC Index (DI) results in three vulnerability levels which are medium with DI 101-140, high with DI around 141-180 and above 180 for high vulnerable of contaminant.

scholarly journals Groundwater Resources Estimation in the Middle of Randublatung Groundwater Basin Based on Geoelectrical Investigation

2021 ◽  
Vol 930 (1) ◽  
pp. 012055
Author(s):  
D L Setyaningsih ◽  
K Setyawan ◽  
D P E Putra ◽  
Salahuddin
Keyword(s):  
Hydraulic Conductivity ◽  
Groundwater Flow ◽  
Groundwater Level ◽  
Groundwater Resources ◽  
Research Area ◽  
Silty Clay ◽  
Groundwater Abstraction ◽  
Aquifer Systems ◽  
Groundwater Basin ◽  
Basin Area

Abstract The high groundwater use in the Randublatung Groundwater Basin area relates to groundwater abstraction for agriculture. Therefore, a question arises on how much groundwater resources in this area may support agricultural groundwater usage. This research has the objective to quantify the groundwater resources in this area. This research conducts a geoelectrical investigation to identify the aquifer’s lithology and observe the groundwater level. The research reveals that resistivity values of subsurface rock layers in the research area range from 0.13 to 124.86 Ωm. The aquifer layer consisted of two aquifer systems, with the hydraulic conductivity varies of the aquifer layer is 0.0001 cm/s until 0.01 cm/s. The aquifer layers estimated to be found at depths vary 5 – 90 m from the ground with thickness range from 10 to 70 m. Meanwhile, the aquiclude layers consisted of clay, silty clay, and sandy clay was estimated to be found at depths varies 0 – 50 m from the ground with thickness varies from 5 to 65 m. by combining those data with a hydraulic gradient of groundwater flow, the dynamic groundwater resources in the research area is estimated between 50 m3/day and 4,691 m3/day.

Evolution of groundwater chemistry on shallow aquifer of Yogyakarta City urban area

2015 ◽  
Vol 3 (2) ◽  
Author(s):  
Doni Prakasa Eka Putra
Keyword(s):  
Shallow Groundwater ◽  
Unconfined Aquifer ◽  
Groundwater Chemistry ◽  
Shallow Aquifer ◽  
Nitrate Content ◽  
New Business ◽  
Urban Settlements ◽  
A Minor ◽  
New Settlements ◽  
Yogyakarta City

Since 1980s, accelerated by urbanization, Yogyakarta City was shifting to many directions defined by main road networks and service centres. Urbanization has transformed rural dwellings to become urban settlements and generated urban agglomeration area. Until now, new business centres, education centres and tourism centres are growing hand in hand with new settlements (formal or informal) without proper provision of water supply and sanitation system. This condition increase the possibility of groundwater contamination from urban wastewater and a change of major chemistry of groundwater as shallow unconfined aquifer is lying under Yogyakarta City. To prove the evolution of groundwater chemistry, old data taken on 1980s were comparing with the recent groundwater chemistry data. The evaluation shows that nitrate content of groundwater in 1980s was a minor anion, but nowadays become a major anion, especially in the shallow groundwater in the centre of Yogyakarta City. This evidence shows that there is an evolution of groundwater chemistry in shallow groundwater below Yogyakarta City due to contamination from un-proper on-site sanitation system. Keywords: Urbanization, Yogyakarta city, rural dwellings, settlements, agglomeration, contamination, groundwater

scholarly journals Investigation of Sentinel-1 Derived Land Subsidence Using Wavelet Tools And Triple Exponential Smoothing Algorithm In Lagos, Nigeria

2021 ◽  
Author(s):  
Femi Emmanuel Ikuemonisan ◽  
Vitalis Chidi Ozebo ◽  
Olawale Babatunde Olatinsu
Keyword(s):  
Soil Moisture ◽  
Land Subsidence ◽  
Groundwater Level ◽  
Exponential Smoothing ◽  
Future Trend ◽  
Smoothing Algorithm ◽  
Groundwater Abstraction ◽  
Groundwater Level Fluctuations ◽  
History Of ◽  
Sbas Insar

Abstract Lagos has a history of long-term groundwater abstraction that is often compounded by the rising indiscriminate private borehole and water well proliferation. This has resulted in various forms of environmental degradation, including land subsidence. Prediction of the temporal evolution of land subsidence is central to successful land subsidence management. In this study, a triple exponential smoothing algorithm was applied to predict the future trend of land subsidence in Lagos. Land subsidence time series is computed with SBAS-InSAR technique with Sentinel-1 acquisitions from 2015 to 2019. Besides, Matlab wavelet tool was implemented to investigate the periodicity within land displacement signal components and to understand the relationship between the observed land subsidence, and groundwater level change and that of soil moisture. Results show that land subsidence in the LOS direction varied approximately between –94 and 15 mm/year. According to the wavelet-based analysis result, land subsidence in Lagos is partly influenced by both groundwater level fluctuations and soil moisture variability. Evaluation of the proposed model indicates good accuracy, with the highest residual of approximately 8%. We then used the model to predict land subsidence between the years 2020 and 2023. The result showed that by the end of 2023 the maximum subsidence would reach 958 mm which is approximately 23% increase.

Sign in / Sign up

Export Citation Format

Share Document