Geography of the world’s groundwater systems

2013 ◽  
pp. 35-66
Keyword(s):  
Groundwater Systems

COMBINED RADIOCARBON AND SEQUENCING ANALYSES TO UNDERSTAND CARBON SOURCES IN GROUNDWATER SYSTEMS

2020 ◽  
Author(s):  
Brian Mailloux ◽  
◽  
Tyler Ellis ◽  
Kazi Matin Ahmed ◽  
Imtiaz Choudhury ◽  
...  
Keyword(s):  
Carbon Sources ◽  
Groundwater Systems

scholarly journals Evaluation of Climate Change Impact on Groundwater Recharge in Groundwater Regions in Taiwan

Water ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1153
Author(s):  
Shih-Jung Wang ◽  
Cheng-Haw Lee ◽  
Chen-Feng Yeh ◽  
Yong Fern Choo ◽  
Hung-Wei Tseng
Keyword(s):  
Climate Change ◽  
Groundwater Recharge ◽  
Climate Change Impact ◽  
Groundwater Resources ◽  
Regression Equations ◽  
Impact Of Climate Change ◽  
Groundwater Systems ◽  
Change Impact ◽  
The Impact ◽  
Assessment Results

Climate change can directly or indirectly influence groundwater resources. The mechanisms of this influence are complex and not easily quantified. Understanding the effect of climate change on groundwater systems can help governments adopt suitable strategies for water resources. The baseflow concept can be used to relate climate conditions to groundwater systems for assessing the climate change impact on groundwater resources. This study applies the stable baseflow concept to the estimation of the groundwater recharge in ten groundwater regions in Taiwan, under historical and climate scenario conditions. The recharge rates at the main river gauge stations in the groundwater regions were assessed using historical data. Regression equations between rainfall and groundwater recharge quantities were developed for the ten groundwater regions. The assessment results can be used for recharge evaluation in Taiwan. The climate change estimation results show that climate change would increase groundwater recharge by 32.6% or decrease it by 28.9% on average under the climate scenarios, with respect to the baseline quantity in Taiwan. The impact of climate change on groundwater systems may be positive. This study proposes a method for assessing the impact of climate change on groundwater systems. The assessment results provide important information for strategy development in groundwater resources management.

scholarly journals High-Arsenic Groundwater in Paleochannels of the Lower Yellow River, China: Distribution and Genesis Mechanisms

Water ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 338
Author(s):  
Chuanshun Zhi ◽  
Wengeng Cao ◽  
Zhen Wang ◽  
Zeyan Li
Keyword(s):  
Yellow River ◽  
The Yellow River ◽  
Rock Interaction ◽  
Lower Yellow River ◽  
The Lower Yellow River ◽  
Groundwater Samples ◽  
Groundwater Systems ◽  
Different Sources ◽  
High Arsenic ◽  
High Arsenic Groundwater

High–arsenic (As) groundwater poses a serious threat to human health. The upper and middle reaches of the Yellow River are well–known areas for the enrichment of high–arsenic groundwater. However, little is known about the distribution characteristics and formation mechanism of high-As groundwater in the lower reach of the Yellow River. There were 203 groundwater samples collected in different groundwater systems of the lower Yellow River for the exploration of its hydrogeochemical characteristics. Results showed that more than 20% of the samples have arsenic concentrations exceeding 10 μg/L. The high-As groundwater was mainly distributed in Late Pleistocene–Holocene aquifers, and the As concentrations in the paleochannels systems (C2 and C4) were significantly higher than that of the paleointerfluve system (C3) and modern Yellow River affected system (C5). The high-As groundwater is characterized by high Fe2+ and NH4+ and low Eh and NO3−, indicating that reductive dissolution of the As–bearing iron oxides is probably the main cause of As release. The arsenic concentrations strikingly showed an increasing tendency as the HCO3− proportion increases, suggesting that HCO3− competitive adsorption may facilitate As mobilization, too. In addition, a Gibbs diagram showed that the evaporation of groundwater could be another significant hydrogeochemical processes, except for the water–rock interaction in the study area. Different sources of aquifer medium and sedimentary structure may be the main reasons for the significant zonation of the As spatial distribution in the lower Yellow River.

scholarly journals Saltwater intrusion into groundwater systems in the Mekong Delta and links to global change

2021 ◽  
Author(s):  
Han Xiao ◽  
Yin Tang ◽  
Hai-Ming Li ◽  
Lu Zhang ◽  
Thanh Ngo-Duc ◽  
...  
Keyword(s):  
Global Change ◽  
Saltwater Intrusion ◽  
Mekong Delta ◽  
Groundwater Systems

scholarly journals Using hydraulic head, chloride and electrical conductivity data to distinguish between mountain-front and mountain-block recharge to basin aquifers

2018 ◽  
Vol 22 (2) ◽  
pp. 1629-1648 ◽  
Author(s):  
Etienne Bresciani ◽  
Roger H. Cranswick ◽  
Eddie W. Banks ◽  
Jordi Batlle-Aguilar ◽  
Peter G. Cook ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Arid Regions ◽  
South Australia ◽  
Hydraulic Head ◽  
Mountain Front ◽  
Quaternary Aquifers ◽  
Groundwater Systems ◽  
Flow Directions ◽  
Electrical Conductivity Data

Abstract. Numerous basin aquifers in arid and semi-arid regions of the world derive a significant portion of their recharge from adjacent mountains. Such recharge can effectively occur through either stream infiltration in the mountain-front zone (mountain-front recharge, MFR) or subsurface flow from the mountain (mountain-block recharge, MBR). While a thorough understanding of recharge mechanisms is critical for conceptualizing and managing groundwater systems, distinguishing between MFR and MBR is difficult. We present an approach that uses hydraulic head, chloride and electrical conductivity (EC) data to distinguish between MFR and MBR. These variables are inexpensive to measure, and may be readily available from hydrogeological databases in many cases. Hydraulic heads can provide information on groundwater flow directions and stream–aquifer interactions, while chloride concentrations and EC values can be used to distinguish between different water sources if these have a distinct signature. Such information can provide evidence for the occurrence or absence of MFR and MBR. This approach is tested through application to the Adelaide Plains basin, South Australia. The recharge mechanisms of this basin have long been debated, in part due to difficulties in understanding the hydraulic role of faults. Both hydraulic head and chloride (equivalently, EC) data consistently suggest that streams are gaining in the adjacent Mount Lofty Ranges and losing when entering the basin. Moreover, the data indicate that not only the Quaternary aquifers but also the deeper Tertiary aquifers are recharged through MFR and not MBR. It is expected that this finding will have a significant impact on the management of water resources in the region. This study demonstrates the relevance of using hydraulic head, chloride and EC data to distinguish between MFR and MBR.

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