scholarly journals Spatial separation of groundwater flow paths from a multi-flow system by a simple mixing model using stable isotopes of oxygen and hydrogen as natural tracers

2007 ◽  
Vol 43 (9) ◽  
Author(s):  
Shinji Nakaya ◽  
Kenji Uesugi ◽  
Yusuke Motodate ◽  
Isao Ohmiya ◽  
Hiroyuki Komiya ◽  
...  
Keyword(s):  
Stable Isotopes ◽  
Groundwater Flow ◽  
Flow System ◽  
Spatial Separation ◽  
Mixing Model ◽  
Flow Paths ◽  
Natural Tracers

Groundwater Flow System in Tokyo Metropolitan Area, Japan: Focusing on Changes in the Last 60 Years

2020 ◽  
Author(s):  
Kosuke Nagano ◽  
Maki Tsujimura ◽  
Ryu Suzuki ◽  
Hiroko Asakura ◽  
Kazunori Tabe
Keyword(s):  
Stable Isotopes ◽  
Groundwater Flow ◽  
Metropolitan Area ◽  
Groundwater Level ◽  
Flow System ◽  
Average Distance ◽  
Groundwater Flow System ◽  
Tokyo Metropolitan ◽  
Tokyo Metropolitan Area ◽  
Lowland Area

<p>     In 1960s, the groundwater level dropped with serious land subsidence due to the excessive pumping of groundwater for economic development in Tokyo Metropolitan area, whereas the groundwater level has been recovered after 1990’s because of the strict groundwater use regulation by the government. A few studies have reported long-term changes in the groundwater including a groundwater level dropdown and the recovery in Southeast Asia, such as Ho Chi Minh City in Vietnam and Jakarta in Indonesia. However, there are not enough investigations to monitor the groundwater flow covering the water level dropdown and the recovery during more than 50 years at the megacities in Asia regions. Therefore, we investigated the change of groundwater flow system at the Tokyo Metropolitan area with a special concern on the lowland area where the impact of land subsidence was particularly large due to an excessive pumping in the 1960's.</p><p>     First, we observed a spatial distribution of hydraulic head and the chemical and stable isotopic compositions in the groundwater and the river water to understand a current groundwater flow system in the whole Tokyo area in 2019, in which the groundwater level is stable. Then, we compared those results with that monitored from 1960’s to 1990’s.</p><p>     Groundwater was sampled from May to October 2019 at multiple boreholes installed at whole of Tokyo area with the depths ranging from 5 m to 260 m, and the main inorganic dissolved ions, stable isotopes (δD, δ<sup>18</sup>O) and the dissolved gas (CFCs, SF<sub>6</sub>) were determined on all samples. The high Cl<sup>-</sup> concentration more than 500 mg/L is limited in the groundwater and the river water in the coastal area with the average distance of 6 km from the sea, whereas the contour line of 500 mg/L intruded inland area with the average distance of 15 km from the coastal line in 1965 and 12 km in 1971, then 8 km in 1994 (Institute of Civil Engineering of the Tokyo Metropolitan Government, 1996). The groundwater hydraulic head is -6 m (m.s.l) at the lowland area in 2019, whereas that was -58 m in 1965, -52 m in 1971, and - 14 m in 1994.</p><p>     The depleted stable isotopes and the higher solute concentrations are observed in the lowland in 2019. Also, SF<sub>6</sub> is not detected in the groundwater at the low land area, whereas we observe the SF<sub>6</sub> concentration ranging from 0.8 pptv to 78 pptv in the upland area. These suggest that the groundwater in the upland has an apparent age of approximately less than one year to 40 years, whereas the groundwater in the lowland is recharged with an age more than 80 years at the higher elevation.</p>

scholarly journals Groundwater flow system of the Kanto Plain estimated from the chemical composition and stable isotopes

2003 ◽  
Vol 33 (3) ◽  
pp. 125-136 ◽  
Author(s):  
Takeshi HAYASHI ◽  
Yohei UCHIDA ◽  
Masaya YASUHARA ◽  
Atsunao MARUI ◽  
Yasuo SAKURA ◽  
...  
Keyword(s):  
Stable Isotopes ◽  
Chemical Composition ◽  
Groundwater Flow ◽  
Flow System ◽  
Groundwater Flow System

Groundwater flow systems analysis on a regional and nation-wide scale in the Netherlands; the use of flow systems analysis in wetland management

1995 ◽  
Vol 31 (8) ◽  
pp. 375-378 ◽  
Author(s):  
F. H. Kloosterman ◽  
R. J. Stuurman ◽  
R. van der Meijden
Keyword(s):  
The Netherlands ◽  
Groundwater Flow ◽  
Systems Analysis ◽  
System Analysis ◽  
Drainage Basin ◽  
Flow System ◽  
Wetland Management ◽  
Groundwater Flow Systems ◽  
Flow Systems ◽  
Strong Relation

The project “National Groundwater Flow System Analysis” in The Netherlands was initiated in 1991 and will last until 1995. Financed by three Dutch Ministries, the project aims at the mapping of the regional groundwater flow systems to support policy makers at national levels and water/nature resources management. Much emphasis is put on biotic aspects such as the relation between groundwater and patterns in vegetation. The results are used in a detailed flow system analysis of the eco-hydrological valuable drainage basin of the brooks Beerze and Reusel in the southern parts of the country. In this study vegetation patterns and hydrological situations were analyzed in present and in historical settings to unravel the changes in the last decades leading to severe deterioration of habitats and wetlands. Historical data on flora from the beginning of this century on the basis of km-grid cells show a strong relation with the historical exfiltration areas where deep alkaline groundwaters rich in calcium-carbonate emerged. Agriculture and man-made changes to the natural drainage systems have led to diminishing nature values. Combining a sound understanding of the groundwater flow systems and the changes in the last decades produced a number of practical and viable measures to restore historical wetland settings and to preserve existing ones.

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