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

2015 ◽  
Vol 3 (2) ◽  
Author(s):  
Doni Prakasa Eka Putra

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

2015 ◽  
Vol 2 (1) ◽  
Author(s):  
Doni Prakasa Eka Putra

In the last two decades, urbanization has transformed Yogyakarta City expanding beyond its administrative area with about one million inhabitants. The City sited on shallow unconfined aquifer has rapidly changed without appropriate access to sanitation and piped water supply. Until now, only 9% of the urban population is served by sewers system and less than 30% of urban population have access to clean water which supplied by the local public water-work. Most of the urban population depend on shallow groundwater for much of their water supply. Regards to the massive used of on-site sanitation systems in the city, contamination of nitrate in shallow groundwater is predicted to occur and surveys of domestic dug wells have revealed a widespread nitrate contamination of the groundwater. Comparison of groundwater nitrate and chloride concentration from several old data and the latest data shows clearly an evidence of the increasing of nitrate concentration and nitrate leaching in the shallow groundwater under Yogyakarta City overtime. Considering the trend, it is no doubt that most of nitrate concentration under urbanized area in the Yogyakarta City will be greater than 50 mg/L in the next several years, if appropriate management action to deal with the on-site sanitation system is not conducted.


Teknik ◽  
2016 ◽  
Vol 37 (1) ◽  
pp. 26
Author(s):  
Thomas Triadi Putranto ◽  
Dian Agus Widiarso ◽  
Fatir Yuslihanu

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.


2020 ◽  
Author(s):  
Claudia Schepp ◽  
Bernd Diekkrüger ◽  
Mathias Becker

<p>Due to their prolonged water availability wetlands are of increasing importance for small scale agriculture in East Africa. In the inundating landscape of central Uganda, inland valley wetlands are a common landscape unit with high potential for crop cultivation year-round. Yet little is known about the hydrological processes which bring out these favourable conditions. This study focusses on the relevance of interflow processes from the slopes into the wetland regarding water and nutrient delivery from different land use types. Hereby special attention is given to water pathways at the transition from upland geology to valley sediments and to nutrient relocation along the slopes.</p><p>Electrical Resistivity Tomography (ERT) was used as a non-invasive method to characterise interflow pathways in the highly variable saprolite geology and for subsurface delineation of the valley sediments. The measurements were complimented by a drilling campaign and infiltration experiments in different depths. Interflow collection pits were installed at the slope toe in order to quantify water and nutrient fluxes towards the wetland during two consecutive years. Additionally, soil moisture and nitrate content in the soil water were quantified at various positions along the slope.</p><p>ERT-imaging supports the hypothesis of a separation between a confined shallow aquifer and the soil water in the wetland sediments. Drilling results and hydrogeochemical analysis of the interflow and this shallow groundwater indicate a connection of the two components via macropores in the upper saprolite at the slope toe. At the same time interflow is transferred to the soil water of the wetland via a sandy loam layer which is found on top of the confining clay-loam layer of the wetland sediments. Both processes are active even during the dry season and therefore water from the interflow is relevant for water storage (shallow aquifer) and agricultural production (soil water) in the wetland.</p><p>Interflow volume and nitrate content both show a fast reaction to rainfall events, while the amount of water and nutrients delivered to the wetland is related to the land-use on the slope. Nitrate content in the soil water on the slopes suggests a relocation of nutrients in the upper soil horizons towards the slope toe. As infiltration capacity of the soil’s A-horizon is higher compared to the B-horizon a second  lateral flow component appears to be present close to the soil surface.</p><p>The results of this study emphasize the relevance of subsurface flow for wetland hydrology and give first explanations of wetland-upland connectivity in a complex saprolite geology.</p>


2017 ◽  
Vol 18 (2) ◽  
pp. 399-407 ◽  
Author(s):  
Bassam Tawabini ◽  
Mohammed Makkawi

Abstract The proximity of shallow groundwater systems to sources of contamination usually exposes them to severe environmental threats. Hazardous pollutants that leak from gas stations, landfills, and industrial facilities may eventually reach the underneath shallow groundwater aquifers, posing risks to human health and the environment. Cleaning contaminated groundwater sources has always been a challenge to the local authorities. This is even more challenging when dealing with difficult pollutants such as methyl tertiary butyl ether (MTBE) due its high solubility in water, poor biodegradability, and poor adsorption onto solids. This study aims to assess the efficiency of a pilot groundwater remediation system to treat a shallow aquifer contaminated with MTBE. The in-house designed and fabricated pilot system combines the technology of circulation wells and UV-based advanced oxidation technology for the breakdown and removal of MTBE from water. An ultraviolet/hydrogen peroxide (UV/H2O2) process was used in this study to remove MTBE from water. The concentration of MTBE was reduced from approximately 1,400 μg/L to as low as 34 μg/L within 30 minutes, with a treatment efficiency of about 98%. The study also assesses the effects of the UV intensity and the treatment time needed to remove the target pollutant.


2018 ◽  
Vol 42 (1) ◽  
pp. 41-54 ◽  
Author(s):  
Shahpara Sheikh Dola ◽  
Khairul Bahsar ◽  
Mazeda Islam ◽  
Md Mizanur Rahman Sarker

Attempt has been made to find the relationship between the basin groundwater flow and the current water chemistry of south-western part of Bangladesh considering their lithological distribution and aquifer condition. The correlation of water chemistry and basin groundwater flow is depicted in the conceptual model. The water-types of shallow groundwater are predominantly Mg-Na-HCO3 and Ca- Mg-Na-HCO3 type. In the deep aquifer of upper delta plain is predominately Na-Cl, Ca-HCO3 and Mg- HCO3 type. In the lower delta plain Na-Cl type of water mainly occurs in the shallow aquifer and occasionally Ca-HCO3, Ca-Mg-Na-HCO3 and Mg-HCO3 type may also occur in shallow aquifer of the eastern part of lower delta plain which could have originated from the recent recharge of rain water. Na- Cl type water is also found in the deep aquifer of lower delta plain. The origin of Na-Cl type water in the deep aquifer of lower delta part might be connate water or present day sea water intrusion. Fresh water occurring in the deep aquifer in the lower delta area is mostly of Mg-Ca-HCO3 and Na-HClO3 types. This type of water originate from intermediate or deep basin flow from the northern part of Bangladesh. The probable source of deep groundwater is Holocene marine transgression (Khan et al. 2000) occurred in 3000–7000 cal years BP and the deep groundwater of Upper Delta plain and Lower Delta plain is clearly influenced by deep basin flow coming from north part of BangladeshJournal of Bangladesh Academy of Sciences, Vol. 42, No. 1, 41-54, 2018


Author(s):  
F. M. Fordyce ◽  
B. É. Ó Dochartaigh ◽  
H. C. Bonsor ◽  
E. L. Ander ◽  
M. T. Graham ◽  
...  

ABSTRACTA new GIS-based screening tool to assess threats to shallow groundwater quality has been trialled in Glasgow, UK. The GRoundwater And Soil Pollutants (GRASP) tool is based on a British Standard method for assessing the threat from potential leaching of metal pollutants in unsaturated soil/superficial materials to shallow groundwater, using data on soil and Quaternary deposit properties, climate and depth to groundwater. GRASP breaks new ground by also incorporating a new Glasgow-wide soil chemistry dataset. GRASP considers eight metals, including chromium, lead and nickel at 1622 soil sample locations. The final output is a map to aid urban management, which highlights areas where shallow groundwater quality may be at risk from current and future surface pollutants. The tool indicated that 13% of soil sample sites in Glasgow present a very high potential threat to groundwater quality, due largely to shallow groundwater depths and high soil metal concentrations. Initial attempts to validate GRASP revealed partial spatial coincidence between the GRASP threat ranks (low, moderate, high and very high) and groundwater chemistry, with statistical correlation between areas of high soil and groundwater metal concentrations for both Cr and Cu (r2>0.152; P<0.05). Validation was hampered by a lack of, and inconsistency in, existing groundwater chemistry data. To address this, standardised subsurface data collection networks have been trialled recently in Glasgow. It is recommended that, once available, new groundwater depth and chemistry information from these networks is used to validate the GRASP model further.


Geofluids ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-21
Author(s):  
Zhaoxu Mi ◽  
Fugang Wang ◽  
Zhijie Yang ◽  
Xufeng Li ◽  
Yujie Diao ◽  
...  

CO2 geological storage in deep saline aquifers is an effective way to reduce CO2 emissions. The injection of CO2 inevitably causes a significant pressure increase in reservoirs. When there exist faults which cut through a deep reservoir and shallow aquifer system, there is a risk of the shallow aquifer being impacted by the changes in reservoir hydrodynamic fields. In this paper, a radial model and a 3D model are established by TOUGH2-ECO2N for the reservoir system in the CO2 geological storage demonstration site in the Junggar Basin to analyze the impact of the CO2 injection on the deep reservoir pressure field and the possible influence on the surrounding shallow groundwater sources. According to the results, the influence of CO2 injection on the reservoir pressure field in different periods and different numbers of well is analyzed. The result shows that the number of injection wells has a significant impact on the reservoir pressure field changes. The greater the number of injection wells is, the greater the pressure field changes. However, after the cessation of CO2 injection, the number of injection wells has little impact on the reservoir pressure recovery time. Under the geological conditions of the site and the constant injection pressure, although the CO2 injection has a significant influence on the pressure field in the deep reservoir, the impact on the shallow groundwater source area is minimal and can be neglected and the existing shallow groundwater sources are safe in the given project scenarios.


2019 ◽  
Vol 98 ◽  
pp. 08005 ◽  
Author(s):  
Yinlei Hao ◽  
Zhonghe Pang ◽  
Tianming Huang ◽  
Yanlong Kong ◽  
Jiao Tian ◽  
...  

Elucidating brine origin and evolution is a fundamental but not easy task especially for coastal geothermal systems with possible marine constituents and multistage evolution, as subsequently physical, chemical and biological alteration processes may mask the original and early-stage signatures. Here chemical and isotopic characteristics of water (D and 18O) and dissolved constituents (13C, 14C, 11B and 87Sr/86Sr) have been utilized to investigate the source and multistage evolution of the Jimo coastal geothermal system in eastern China, with dramatic differences of geochemical characteristics observed within a 0.2 km2 area. Results show that geothermal water is derived from paleo-meteoric water and has undergone a 3-stages evolution that involves: (1) Dissolution of marine halite and potash salts in the deep reservoir; (2) Water-rock reactions especially cation exchange produces a Cl-Na-Ca type water as deep geothermal water upwells along the fault zone; (3) A minor (<0.3%) addition of fossil seawater to the shallow aquifer that produces Cl-Na type waters in the west, whereas sulfide oxidation and dissolution of aluminosilicate and carbonates in the east produces Cl-Na-Ca type waters. The methodology utilized in this study offers a means of examining other similar complex geochemical systems having a multistage evolution.


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