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Affiliation |
Graduate School of Engineering Science Department of Systems Design Engineering Civil and Environmental Engineering Course |
AMITA Kazuhiro
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Graduating School 【 display / non-display 】
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1991.04-1995.03
Kochi University Faculty of Science Graduated
Graduate School 【 display / non-display 】
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-2003.03
Kyoto University Graduate School, Division of Natural Science Doctor's Course Completed
Campus Career 【 display / non-display 】
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2018.04-Now
Akita University Graduate School of Engineering Science Department of Systems Design Engineering Civil and Environmental Engineering Course Assistant Professor
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2016.04-2018.03
Akita University Graduate School of Engineering Science Research Center for Engineering Science Assistant Professor
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2014.04-2016.03
Akita University Graduate School of Engineering and Resource Science Research Center for Engineering Science Assistant Professor
Research Areas 【 display / non-display 】
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Natural Science / Atmospheric and hydrospheric sciences / 水資源・地表環境学
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Environmental Science/Agriculture Science / Environmental impact assessment
Research Achievements 【 display / non-display 】
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Study on Neutralization of Tamagawa Acidic Water Using Iron and Steel Slags
KAGAYA Fumito, SAITO Noritoshi, MINAMIDA Yu, AMITA Kazuhiro
Journal of the Society of Materials Science, Japan ( The Society of Materials Science, Japan ) 74 ( 4 ) 267 - 272 2025.04
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Hydrological regime in volcanic lakes based on lake-water leakage: Review and interpretation
CHIKITA Kazuhisa, GOTO Akio, OKADA Jun, OYAGI Hideo, AMITA Kazuhiro
Journal of the Japanese Society of Physical Hydrology ( Japanese Society of Physical Hydrology ) 7 ( 1 ) 3 - 13 2025
Focusing on a hydrological phenomenon of groundwater outflow Gout from lakes, relations between calculated Gout and hydrological conditions of the lakes were reviewed and interpreted for some caldera lakes and a crater lake, where their water budgets, groundwater outflow Gout and groundwater inflow Gin had been quantified. Although the water budget periods were then adopted at a wide range of several days to several years, hydrological features of the volcanoes were clarified by comprehensively grasping relations between calculated Gout and lake level or lake volume. The net groundwater input (Gin – Gout) was numerically obtained by estimating the hydrological budget of each lake, and then the Gin or Gout value was obtained by the following three ways: 1) by calculating a Gin value as a baseflow in a completely ice-covered period when both evaporation and precipitation at lake water surface can be ignored, 2) by solving the simultaneous equations for hydrological and chemical budgets, and 3) by simulating a lake water level based on a Gin value from the surrounding catchment calculated by a tank model. The calculated Gout values exhibited the high correlation (R2 = 0.988, p <0.01) with the lake volume, suggesting that Gout occurs as a confined groundwater flow. It is also found out that, reflecting the permeability of the volcano, the lake has a different adjustment ability to water level.
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Prototype geochemical towing observation system for detection of coastal seafloor discharge of volcanic fluids and its evaluation of performance at volcanic CO<sub>2</sub> upwelling area
OHSAWA Shinji, AMITA Kazuhiro, MISHIMA Taketoshi, SAITO Kei, MASAMOTO Futo, TAKAHASHI Hiroshi, MORIKAWA Noritoshi
Journal of Japanese Association of Hydrological Sciences ( THE JAPANESE ASSOCIATION OF HYDOROLOGICAL SCIENCES ) 52 ( 3 ) 107 - 121 2022.12
<p>A prototype “Geochemical Towing Observation System" was developed to detect the presence of volcanic fluids discharging from the coastal seafloor in shallow waters from the sea. We confirmed the stable operation of the observation system and evaluated its ability to detect volcanic fluid discharge in one of the coastal waters of Himeshima Island (Oita Prefecture, Japan), where volcanic CO<sub>2</sub> gas has been discharged from the seafloor. In the observed sea area, as the concentration of dissolved inorganic carbon (DIC) in seawater increases, its δ<sup>13</sup>C value changes toward the estimated δ<sup>13</sup>C of volcanic CO<sub>2</sub>, so we believe that the observation system has successfully captured the seafloor discharge of volcanic fluids. In addition to DIC, a significant change in redox potential (ORP/Eh) also appeared, which can be explained by the detection of H<sub>2</sub>S dissolved in seawater contained in seafloor gases. Combined measurements of <sup>222</sup>Rn, salinity corresponding to electric conductivity, and water temperature, which have been effective in detecting submarine groundwater and hot spring water discharges from the seafloor in the Beppu Hot Springs coastal area in the back of Beppu Bay, showed no expected changes. This may indicate that submarine groundwater discharge from the seafloor along the coast of Himeshima Island is not significant and that gas discharge is the main cause.</p>
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STUDY ON IMPROVEMENT OF TAMAGAWA ACIDIC WATER USING FLY ASH GRANUTRALIZER
SAITO Noritoshi, KAGAYA Fumito, IKEUCHI Takao, SASAKI Asuka, MINAMIDA Yu, AMITA Kazuhiro
Journal of Japan Society of Civil Engineers, Ser. G (Environmental Research) ( Japan Society of Civil Engineers ) 78 ( 5 ) I_233 - I_238 2022
<p> The Tamagawa acidic water originates from the Tamagawa hot springs in eastern Akita Prefecture. Currently, the pH of Lake Tazawa has increased from 4.6 to about 5.8 due to the operation of a neutralization treatment facility. However, it has not recovered to 6.8, and the water environment and ecosystem have not yet recovered. In this study, a neutralizer was prepared using fly ash to improve Tamagawa acidic water and to expand the use of coal ash. Neutralization experiments were conducted to evaluate the effectiveness of the neutralizer by analyzing pH changes, the neutralizer, and treated water. The results showed that the neutralizer did not disintegrate or leach heavy metal ions in the weakly acidic range, suggesting that the neutralizer could be used stably.</p>
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A study on water balance and water quality improvement in Lake Tazawa
OYAGI Hideo, CHIKITA Kazuhisa, AMITA Kazuhiro, Fujii Tomoyasu
Proceedings of the General Meeting of the Association of Japanese Geographers ( The Association of Japanese Geographers ) 2020 ( 0 ) 2020
<p>A study on water balance and water quality improvement in Lake Tazawa</p>