scholarly journals ESTIMATION OF GROUNDWATER FLOW SYSTEM IN THE KUROBE RIVER BASIN BASED ON GROUNDWATER LEVEL AND WATER QUALITY OBSERVATIONS

2015 ◽  
Vol 71 (5) ◽  
pp. I_111-I_116
Author(s):  
Ryuhei KITA ◽  
Taichi TEBAKARI
Keyword(s):  
Water Quality ◽  
Groundwater Flow ◽  
River Basin ◽  
Groundwater Level ◽  
Flow System ◽  
Groundwater Flow System

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 Simulation of the regional groundwater-flow system in the St. Louis River basin, Minnesota

2019 ◽  
Author(s):  
Megan J. Haserodt ◽  
Randall J. Hunt ◽  
Timothy K. Cowdery ◽  
Andrew T. Leaf ◽  
Anna C. Baker
Keyword(s):  
Groundwater Flow ◽  
River Basin ◽  
Flow System ◽  
Groundwater Flow System ◽  
Regional Groundwater

scholarly journals Distribution of 36Cl in the Yoro River Basin, Central Japan, and Its Relation to the Residence Time of the Regional Groundwater Flow System

Water ◽  
2011 ◽  
Vol 3 (1) ◽  
pp. 64-78 ◽  
Author(s):  
Yuki Tosaki ◽  
Norio Tase ◽  
Akihiko Kondoh ◽  
Kimikazu Sasa ◽  
Tsutomu Takahashi ◽  
...  
Keyword(s):  
Groundwater Flow ◽  
River Basin ◽  
Residence Time ◽  
Flow System ◽  
Central Japan ◽  
Groundwater Flow System ◽  
Regional Groundwater

scholarly journals Implications of Self-Potential Distribution for Groundwater Flow System in a Nonvolcanic Mountain Slope

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Tada-nori Goto ◽  
Kazuya Kondo ◽  
Rina Ito ◽  
Keisuke Esaki ◽  
Yasuo Oouchi ◽  
...  
Keyword(s):  
Groundwater Flow ◽  
General Trend ◽  
Flow System ◽  
Ground Surface ◽  
Mountain Slope ◽  
Infiltration Process ◽  
Groundwater Flow System ◽  
Self Potential ◽  
Sp Anomaly ◽  
Fft Analysis

Self-potential (SP) measurements were conducted at Mt. Tsukuba, Japan, which is a nonvolcanic mountain, to infer groundwater flow system in the mountain. Survey routes were set around the northern slope, and the reliability of observed SP anomaly was checked by using SP values along parallel survey routes; the error was almost within 10 mV. The FFT analysis of the spatial SP distribution allows us a separation of raw data into two components with shorter and longer wavelength. In the shorter (altitudinal) wavelength than ∼200 meters, several positive SP peaks of more than 100 mV in magnitude are present, which indicate shallow perched water discharges along the slope. In the regional SP pattern of longer wavelength, there are two major perturbations from the general trend reflecting the topographic effect. By comparing the SP and hydrological data, the perturbation around the foothill is interpreted to be caused by heterogeneous infiltration at the ground surface. The perturbation around the summit is also interpreted to be caused by heterogeneous infiltration process, based on a simplified numerical modeling of SP. As a result, the SP pattern is well explained by groundwater flow and infiltration processes. Thus, SP data is thought to be very useful for understanding of groundwater flow system on a mountain scale.

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