九州大学 研究者情報
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広城 吉成(ひろしろ よしなり) データ更新日:2022.04.28

准教授 /  工学研究院 環境社会部門 水・資源循環システム学


原著論文
1. 武藤圭誠,広城吉成, 水循環解析モデルを用いたウォーターバンキング効果の分析-福岡県瑞梅寺川流域を対象として-, 土木学会論文集G(環境), Vol.77, No.5, I_9-I_15, 土木学会論文集G(環境)Vol.77,No.5, I_9-I_15, Sep. 2021., 2021.09, 瑞梅寺川流域では豊かな自然環境と貴重な生態系を有している.一方で,都市開発や水田の減少に伴い地下水涵養量の減少が懸念されている.このような水循環系に対する問題の解決策としてウォーターバンキング(以下WB)が注目されている.
本研究では同流域を対象とした水収支解析を行い,WBの効果を検証した.その結果,荒地と水田にWBを行った場合の差が明らかになった他,WBにより地下水涵養量が約7%増加,表面流出量が約15.5%減少,全余剰表流水を7%地下に貯留できることが確認された.また,地下水淡水位はWB直後に上昇し,地下水塩水位に関してはWBを長期間実施するほど地下水の塩水化が低減した.さらに,1差分格子あたりでは周辺の表面流出率が一様に低く,流出係数が大きい土地利用ほどWBによる地下水位改善が効果的であることが判明した.
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2. Shinichi Ozaki, Christel Abi Akl, Tatsuya Nagino, Yoshinari Hiroshiro, Investigating Effect of Pumping Ratio on Effectiveness of Barrier Wells for Saltwater Intrusion: Lab-Scale Experiments and Numerical Modeling, Water, 10.3390/w13152100, Vol.13(Issue15), 2100, Water, Vol.13(Issue15), 2100; DOI:10.3390/w13152100, 2021.07, Saltwater intrusion, leading to the salinization of fresh groundwater, is the most challenging problem in coastal regions. Saltwater pumping from a barrier well is widely applied to prevent saltwater intrusion. Owing to its easy installation, many studies have investigated saltwater pumping. However, quantitative relationships between the barrier and inland production wells have not been revealed. In this study, lab-scale experiments were conducted to examine the effectiveness of a barrier well on the possible flow rate of freshwater from a production well. Moreover, a two-dimensional numerical model was created and simulated under the same conditions as those used in the experiments to analyze the experimental results. Consequently, a critical pumping ratio of 1.9 was obtained. In the numerical simulation, it was confirmed that an upconing of highly concentrated saltwater toward the barrier well was observed when the pumping ratio was less than the critical ratio. In conclusion, there is a critical pumping ratio between the barrier and the production well, and saltwater intrusion can be controlled by keeping the pumping rates under the critical ratio. Although further studies have yet to be conducted on a practical scale, this study showed the potential of the pumping ratio control to manage saltwater intrusion.
Keywords: salinity-affected coastal aquifer; saltwater intrusion; barrier well; production well; critical groundwater pumping ratio; laboratory experiment; global warming; sandy aquifer.
3. 西山浩司,横田いずみ,広城吉成,朝位孝二, 自己組織化マップに基づく広島県の豪雨災害を引き起こした気象場パターンの分析, 水工学論文集,土木学会論文集B1(水工学), 第64巻, No.4, 2019.11.
4. @広城吉成,#武藤圭誠, 地下水湧出に伴う栄養塩負荷量の推定-福岡市今津干潟を事例として-, 土木学会論文集G, 75, 5, 119-126, 2019.08.
5. 松本大毅,広城吉成,木下詔彦,堤敦, 小流域河川の地下水-表流水間の相互作用を考慮した水循環解析―大原川を事例としてー, 土木学会水工学河川技術論文集, 第25巻,7-12, 2019.06.
6. @広城吉成、#井辺弘貴、#重松藍、@森山晃、@松岡史郎, 浄水過程におけるPAC(ポリ塩化アルミニウム)の凝集に及ぼすイオン状シリカの影響, 水道協会雑誌, 87, 10, 11-16, 第87巻,第10号(第1009号), p.11-16(ISSN 0371-0785), 2018.10, 水道原水である河川水が降雨に伴い濁りが増すと、浄水場での最適PAC注入濃度も多くなることはよく知られたことである。しかしながら、大分県杵築市浄水場では、無水降水期間に水道原水である河川水の濁度が上がっていないのにも関わらず、PACの最適注入濃度が増加するとの報告があった。杵築市浄水場では水道原水の一つとして場内の地下水も利用しており、特にイオン状シリカ濃度が高いことがわかった。水道原水中の高濃度のイオン状シリカと最適PAC注入濃度の定量的関係をジャーテストによって調査し、高濃度のイオン状シリカはPACの凝集剤としての働きを阻害することがわかった。.
7. 広城 吉成, 横田 雅紀, 2005年福岡県西方沖地震による地下水位の変動特性, 地盤工学会、Kansai Geo-Symposium2017論文集, 46-49, 2017.11.
8. Yoshinari HIROSHIRO, Masataka MATSUMOTO, Akihiko KINOSHITA, Atushi TSUTSUMI, Hydrological Analysis of Interaction between Surface and Subsurface Water in the Middle Basin of the Obaru River, Western Fukuoka, Japan, International Symposium on Earth Science and Technology 2017, 2017.11, To reproduce an accurate hydrological cycle condition quantitatively with numerical analysis model, it is essential to incorporate hydraulic geological conditions of the investigated area as clearly as possible. In the previous research, although the river flow discharge was calculated by the TSUTSUMI-JINNO model as will hereinafter be described, the numerical value of the river flow discharge at the most downstream observation point was considerably higher than the observation value. Therefore, hydraulic geological conditions of the basin had to be reconsidered. In this paper, in order to reproduce the actual surface water-groundwater relationship, a new model is developed by adding the following the two conditions: 1)the existence of the former channel of the Obaru river, and 2)phenomenon of groundwater flow out to river as gaining river(stream) is also taken into account the phenomenon of river water flow in to groundwater as losing river(stream) as well. As the results, considering the two phenomena, the calculated river flow discharge and its observed value showed good correlation at the observation point. To reproduce real hydrological cycle condition quantitatively, it is important that evaluating the accurate hydraulic geological conditions in the investigated area are incorporated in the model..
9. Yoshinari HIROSHIRO, Keisuke KONISHI, Kento TERASHIMA, Atsushi TSUTSUMI, Two Different Modeling Approaches for Quantitative Analysis of Nutrient Input from River and Groundwater to Imazu Bay in Fukuoka, Japan, Proceedings of International Symposium on Earth Science and Technology 2016, 394-397, 394-397, 2016.12.
10. 広城 吉成, 森田祐輝, 右田義臣, 天日美薫, 田籠久也, 竹チップ散布による地下水水質への影響評価, 土木学会論文集G, Vol.72, No.5, 119-126, 2016.08.
11. Yoshinari HIROSHIRO, Keisuke KONISHI, Estimation of amount of groundwater pumping discharge and its effect on salinization of groundwater around Ito Campus, Kyushu University, MEMOIRS OF THE FACULTY OF ENGINEERING KYUSHU UNIVERSITY, Vol.76, No.1, 2016.07, Kyushu University has been constructing its new campus (Ito Campus) in an area spanning the Motooka-Kuwabara district in Fukuoka City. Agriculture is active in this area and a large amount of groundwater is used for irrigation and horticultural facilities. In recent years, land development for house building has proceeded and one of groundwater recharge sources, paddy area has decreased. Therefore, it is the urgent need to grasp the total amount of groundwater discharge by pumping wells. It was estimated that dividing into three usage ways; for living, agriculture and business. The result shows the daily average groundwater discharge is approximately 635m3 and the percentages of groundwater usage are 59 percent for agriculture, 38 percent for living and 3 percent for business. Next, saline-affected groundwater by effects of groundwater pumping was evaluated from value changes of EC (electrical conductivity), Na and Cl at the wells for agriculture. Consequently, it was revealed that groundwater pumping has an effect on salinization of groundwater and its influences were reflected on the groundwater quality about one month later..
12. Yoshinari HIROSHIRO, Keisuke Konishi, Kento Terashima, Atushi Tsutsumi, Quantive Analysis of Nutrient Inflow from River and Groundwater to Imazu Bay in Fukuoka, Japan, 18th International Conference on Environment and Water Resource Management, 3320-3325, 2016.05.
13. 広城 吉成, 三浦聖二, 砂によるヒ素除去効果の実験的評価, 土木学会論文集B1(水工学), 水工学論文集第59巻,土木学会論文集B1(水工学),Vol.71, No.4, p.241-p.246, 2015.02.
14. 広城 吉成, 横田 いずみ, 西山 浩司, 神野 健二, 藤野 恭裕, 塚原 健一, 若い世代の節水に関する意識調査, 水道協会誌, 83, 7, 2014.07.
15. M. A. Halim, Ratan K. Majumder, G. Rasul, Y. Hirosiro, K. Sasaki, J. Shimada, K. Jinno, Geochemical Evaluation of Arsenic and Manganese in Shallow Groundwater and Core Sediment in Singair Upazila, Central Bangladesh, Arabian Journal for Science and Engineering, 10.1007/s13369-014-1111-x, 39, 7, 5585-5601, 2014.01, [URL], Geochemical characteristics of shallow groundwaters and core sediments are studied to better understand the sources and transportation process responsible for As and Mn enrichment in Singair Upazila of Manikgonj District in Bangladesh. Results demonstrate that the groundwater is mostly of Ca-HCO3 and Ca-Mg-HCO3 types. Concentrations of As in groundwater ranged from 1 to 159 μg/L, with about 59% of these exceeded the WHO drinking water guideline of 10 mg/L. In addition, all groundwater samples had higher concentrations of Mn (0.6-5.7 mg/L) and Fe (0.9-16.5 mg/L) than the WHO drinking water guidelines (0.4 and 0.3 μg/L, respectively). Most groundwaters contained both As(III) and As(V) species in which the concentration of As(III) was generally higher than that of As(V). High concentration of As (23 mg/kg) with elevated levels of FeO, MnO and TOC were found within the upper 15 m of silty clay sediments. Multivariate geostatistical analysis showed that dissolution of the Fe-Mn oxides was the dominant process of As and Mn release in groundwater. Geochemical modeling suggested that the concentrations of As, Mn, Fe and PO43- in groundwaters were also influenced by secondary minerals phases in addition to redox processes..
16. 川上馨詞, 越智啓太, 渡邉佑輔, 広城 吉成, 地下水中の酸化還元反応を考慮した断面2次元ヒ素輸送モデル, 土木学会論文集B1(水工学) , Vol.69, No.4, 565-570, 2013.02.
17. Abdur Razzak, Kenji Jinno, Yoshinari Hiroshiro, Development of numerical removal model of arsenic from groundwater, Memoirs of the Faculty of Engineering, Kyushu University, 72, 3, 85-102, 2012.10, There is a tremendous demand for developing efficient methods for arsenic removal from drinking waters due to its severe toxicity effect on living beings. In order to predict an appropriate technique for arsenic removal from groundwater a numerical model that is able to describe the removal of arsenic and other background species from the groundwater considering chemical and biochemical processes has been developed in the present paper. Based on the adsorption/co-precipitation of arsenic with iron(III) hydroxides, the behavior of arsenic and iron under oxidation dominant environment including advection, dispersion, molecular diffusion and the microbially mediated chemical processes are also presented. The arsenic transport equation and the balance equations are solved numerically using the finite difference method and method of characteristics (MOC), subject to prescribed initial and boundary conditions are also presented. The kinetic sub model describes the heterotrophic metabolisms of several groups of microorganisms. Microbial growth is assumed to follow Monod type kinetics. The results of the removal simulation model demonstrated that availability of substrate (e.g. organic carbon), maximum growth rate, yield coefficient of bacteria, the precipitation rate of iron-hydroxide and the adsorption/precipitation rate of arsenic with iron hydroxide were important parameters which affected the removal of arsenic from groundwater. Among all the parameters organic carbon concentration proved as the most important..
18. Kosuke Sato,Cintia Bartacchi Uvo,Yoshinari Hiroshiro,Koji Nishiyama,H. Yasuda,X.C. Zhang,J.Y. Zheng, Decadal Variation in Rainfall in the Yellow River Basin, International Symposium on Earth Science and Technology 2011, 549-552, 2011.12.
19. 安元純,広城吉成,末益大嗣,高岡秀朋,神野健二, 有明海沿岸火山岩地域における海底湧水の湧出機構と栄養塩の輸送特性, 水工学論文集, 第55巻, p.589-594, 2011.02.
20. 川上馨詞,安藤利博,小田圭太,広城吉成, 酸化還元状況下における鉄-ヒ素の吸脱着機構を考慮したヒ素輸送モデル, 水工学論文集, 第55巻, p.607-612, 2011.02.
21. M.A. Halim, R.K. Majumder, S.A. Nessa, Y. Hiroshiro, K. Sasaki, B.B. Saha, A. Saepuloh and K. Jinno, Evaluation of processes controlling the geochemical constituents in deep groundwater in Bangladesh: spatial variability on arsenic and boron enrichment, Journal of Hazardous Materials, 10.1016/j.jhazmat.2010.01.008, Vol.180, 50-62, 2010.10.
22. Edangodage D.P. Perera, Kenji Jinno, Atsushi Tsutsumi, Yoshinari Hiroshiro, A numerical study of saline contamination of a coastal aquifer, Proceedings of the Institution of Civil Engineers: Water Management, 10.1680/wama.2010.163.7.367, 163, 7, 367-375, 2010.07, [URL], A three-dimensional mathematical model of variable density groundwater flow and miscible solute transport is developed to investigate the saltwater contamination of a coastal aquifer in west Japan. The selected area is an agricultural region located on a coastal aquifer where the groundwater is being consumed continuously as the main water source for drinking, greenhouses and industries. The salinity of the pumped water has been analysed periodically and it has been found that the threat of saltwater intrusion is emerging due to the continuous exploitation of groundwater. Owing to the distributed nature of pumping-well locations and nonuniform geological conditions, a three-dimensional model is needed to understand the saline contamination of the coastal aquifer. A numerical model was built by using the finite difference framework, taking into account the development of a transition zone and the variation of fluid density within it. The model simulates the saturated and unsaturated zone groundwater flow under the influence of a variable density situation in the coastal aquifer. Moreover, it can be used as a numerical tool to simulate the salinity contamination of the freshwater in this coastal aquifer..
23. Shiguo XU, Changwu YU, Yoshinari Hiroshiro, Migration behavior of Fe, Cu, Zn, and Mo in alkaline tailings from Lanjiagou porphyry molybdenum deposits, Northern China, MEMOIRS OF THE FACULTY OF ENGINEERING KYUSHU UNIVERSITY, Vol.70, No.2, 2010.06.
24. Shiguo XU, Yong DING, Kenji Jinno, Wenyi LI, Yoshinari Hiroshiro , Feasibility and Quantification Analysis of Floodwater Utilization, MEMOIRS OF THE FACULTY OF ENGINEERING KYUSHU UNIVERSITY, Vol.70, No.1, 2010.03.
25. 広城吉成,松本大毅,横田雅紀,堤敦,神野健二 , 結晶片岩-花崗閃緑岩地質境界における地下水・表流水の交流特性, 水工学論文集, 第54巻, 589-594, 2010.02.
26. 土方栄示,広城吉成,神野健二 , 冬期と夏期における稲わら混合水田土壌を用いた下水処理水中の窒素除去実験, 水工学論文集, 第54巻, 619-624, 2010.02.
27. 野村哲裕,堤敦,神野健二,広城吉成, 糸島半島における水循環機構の解析, 水工学論文集, 第54巻, 577-582, 2010.02.
28. Md Abdul Halim, Ratan K. Majumder, Syeda Afsarun Nessa, Keita Oda, Yoshinari Hiroshiro, Kenji Jinno, Arsenic in shallow aquifer in the eastern region of Bangladesh
Insights from principal component analysis of groundwater compositions, Environmental Monitoring and Assessment, 10.1007/s10661-009-0760-9, 161, 1-4, 453-472, 2010.02, [URL], Probable sources and mechanisms of arsenic (As) release in shallow aquifer in eastern Bangladesh are evaluated using statistical analysis of groundwater compositions. Dissolved As in 39 samples ranged from 8.05 to 341.5 μg/L with an average of 95.14 μg/L. Ninety seven percent of wells exceed the WHO limit (10 μg/L) for safe drinking water. Principal component analysis is applied to reduce 16 measured compositional variables to five significant components (principal components-PCs) that explain 86.63% of the geochemical variance. Two component loadings, namely PC 1 and PC 2 (45.31% and 23.05%) indicate the natural processes within the aquifers in which organic matter is a key reactant in the weathering reactions. Four groups of wells are defined by the PCA and each group of wells represents distinct physicochemical characteristics. Among them, group III groundwater shows higher As concentration together with high concentrations of Fe, Mn, dissolved organic carbon, PO43 and HCO3- than groups I and II. Speciation calculations suggest that only wells of group III are saturated with respect to siderite, and all groups of samples are supersaturated with respect of rhodochrosite. The relationship of As with these parameters in the different groups of wells of the study area suggests that reductive dissolution of Fe-Mn oxyhydroxides with microbially mediated degradation of organic matter is considered to be the dominant processes to release As in groundwater..
29. M.A. Halim, R.K. Majumder, S.A. Nessa, Y. Hiroshiro, K. Sasaki, B.B. Saha, A. Saepuloh and K. Jinno , Evaluation of processes controlling the geochemical constituents in deep groundwater in Bangladesh: spatial variability on arsenic and boron enrichment
, Journal of Hazardous Materials, 10.1016/j.jhazmat.2010.01.008, 2010.01.
30. E.D.P. Perera, Kenji Jinno,Yoshinari Hiroshiro , Bacteria-mediated Reduction and Precipitation of Fe(OH)3 and FeS in the Subsurface of a Coastal Aquifer: A Numerical Investigation, Water Quality, Exposure and Health, Springer, 10.1007/s12403-009-0021-8, 2010.01.
31. E. D.P. Perera, K. Jinno, Yoshinari Hiroshiro, A. Tsutsumi, Numerical simulation of electric conductivity fluctuations due to groundwater pumping in a coastal aquifer, Advances in Geosciences
Volume 17: Hydrological Science (HS)
, 10.1142/7158-vol17, 79-88, 2010.01, [URL], The Motooka area of Fukuoka prefecture of Japan is an agricultural area located on a coastal aquifer where the groundwater is being exploited for drinking and green house agriculture. The groundwater is the main water supply for drinking and greenhouse agriculture. With the increased water demand, groundwater is being extracted at the rate of 1,200m3/day. The salinity of the pumped water has been analyzed periodically and it has found that the aquifer is affected by the saltwater intrusion due to over exploitation of groundwater. The high salinity of pumped water is not suitable for both drinking and greenhouse farming. The salinity fluctuation in the pumped groundwater has become an important issue to attract much attention of the green house farmers due to its significant effect on their crops. To the authors' knowledge, research on the salinity fluctuations with groundwater pumping and their effects on seasonal recharge of groundwater in the Motooka region has not been conducted thus far. In the field of numerical modeling of saltwater intrusion, so far the simulation of salinity fluctuations is not significant. Therefore authors found a keen interest on numerical simulation of the saltwater intrusion and the salinity fluctuation phenomenon in the Motooka. To this end, a three dimensional density dependent finite difference solute transport numerical model was developed. Due to the distributed nature of pumping well locations and non-uniform geological conditions; a three-dimensional model was needed to understand the saltwater intrusion and salinity fluctuations in the Motooka. The developed model is capable of simulating the saltwater intrusion and the salinity fluctuations due to groundwater pumping for satisfactory extent..
32. E. D.P. Perera, K. Jinno, Yoshinari Hiroshiro, A. Tsutsumi, Numerical simulation of electric conductivity fluctuations due to groundwater pumping in a coastal aquifer, Advances in Geosciences
Volume 17: Hydrological Science (HS)
, 10.1142/7158-vol17, 79-88, 2010.01, [URL], The Motooka area of Fukuoka prefecture of Japan is an agricultural area located on a coastal aquifer where the groundwater is being exploited for drinking and green house agriculture. The groundwater is the main water supply for drinking and greenhouse agriculture. With the increased water demand, groundwater is being extracted at the rate of 1,200m3/day. The salinity of the pumped water has been analyzed periodically and it has found that the aquifer is affected by the saltwater intrusion due to over exploitation of groundwater. The high salinity of pumped water is not suitable for both drinking and greenhouse farming. The salinity fluctuation in the pumped groundwater has become an important issue to attract much attention of the green house farmers due to its significant effect on their crops. To the authors' knowledge, research on the salinity fluctuations with groundwater pumping and their effects on seasonal recharge of groundwater in the Motooka region has not been conducted thus far. In the field of numerical modeling of saltwater intrusion, so far the simulation of salinity fluctuations is not significant. Therefore authors found a keen interest on numerical simulation of the saltwater intrusion and the salinity fluctuation phenomenon in the Motooka. To this end, a three dimensional density dependent finite difference solute transport numerical model was developed. Due to the distributed nature of pumping well locations and non-uniform geological conditions; a three-dimensional model was needed to understand the saltwater intrusion and salinity fluctuations in the Motooka. The developed model is capable of simulating the saltwater intrusion and the salinity fluctuations due to groundwater pumping for satisfactory extent..
33. E. D.P. Perera, K. Jinno, Yoshinari Hiroshiro, A. Tsutsumi, Numerical simulation of electric conductivity fluctuations due to groundwater pumping in a coastal aquifer, Advances in Geosciences
Volume 17: Hydrological Science (HS)
, 10.1142/7158-vol17, 79-88, 2010.01, [URL], The Motooka area of Fukuoka prefecture of Japan is an agricultural area located on a coastal aquifer where the groundwater is being exploited for drinking and green house agriculture. The groundwater is the main water supply for drinking and greenhouse agriculture. With the increased water demand, groundwater is being extracted at the rate of 1,200m3/day. The salinity of the pumped water has been analyzed periodically and it has found that the aquifer is affected by the saltwater intrusion due to over exploitation of groundwater. The high salinity of pumped water is not suitable for both drinking and greenhouse farming. The salinity fluctuation in the pumped groundwater has become an important issue to attract much attention of the green house farmers due to its significant effect on their crops. To the authors' knowledge, research on the salinity fluctuations with groundwater pumping and their effects on seasonal recharge of groundwater in the Motooka region has not been conducted thus far. In the field of numerical modeling of saltwater intrusion, so far the simulation of salinity fluctuations is not significant. Therefore authors found a keen interest on numerical simulation of the saltwater intrusion and the salinity fluctuation phenomenon in the Motooka. To this end, a three dimensional density dependent finite difference solute transport numerical model was developed. Due to the distributed nature of pumping well locations and non-uniform geological conditions; a three-dimensional model was needed to understand the saltwater intrusion and salinity fluctuations in the Motooka. The developed model is capable of simulating the saltwater intrusion and the salinity fluctuations due to groundwater pumping for satisfactory extent..
34. Md. Abdul HALIM, Ratan K. MAJUMDER, Keita ODA, Yoshinari Hiroshiro, Keiko SASAKI and Kenji JINNO, Assessment of Processes Controlling the Geochemical Constituents in Deep Groundwater of Bangladesh with Spatial Variability on Arsenic and Boron Enrichment, International Symposium on Earth Science and Technology 2009, 167-170, 2009.12.
35. E. D.P. Perera, K. Jinno, Yoshinari Hiroshiro, A. Tsutsumi, Evaluation of seawater intrusion to a coastal aquifer by developing a three dimensional numerical model, International Conference on Hydrological Changes and Management from Headwaters to the Ocean, HYDROCHANGE 2008
From Headwaters to the Ocean
Hydrological Changes and Watershed Management - Proc. of the International Conference on Hydrological Changes and Management from Headwaters to the Ocean, HYDROCHAN 2008
, 231-236, 2009.12, The Motooka region in Fukuoka, Japan is a coastal region where agriculture is dominant. The green houses and wineries cover their water demand from groundwater. With the increased water demand, seawater intrusion is identified as an alarming threat to the Motooka coastal aquifer in near future. The measured electric conductivities of the water samples have been analyzed periodically. Until now the measured electric conductivities do not show high values but those values convince the emerging threat of seawater intrusion in this aquifer in future if groundwater will be pumped at current rate further. Therefore it is worth to conduct a numerical study of seawater intrusion and its impact to the Motooka area since the sustainability of the aquifer is inevitable for the future groundwater development and agriculture. In this paper a numerical study of the seawater intrusion of the Motooka is discussed. The numerical model presented in this paper was developed by coupling the groundwater flow equation with the mass transport equation to simulate the density dependent solute transport in the three dimensional space. The usage of this model as a management tool to simulate the salinity variation with groundwater pumping is emphasized. The numerical model was adequately capable of simulating the seawater intrusion and numerical results show a satisfactory agreement with the field observations..
36. E. D.P. Perera, K. Jinno, A. Tsutsumi, Y. Hiroshiro, Three dimensional solute transport numerical modeling of salinity fluctuations in a coastal aquifer, 18th World IMACS Congress and International Congress on Modelling and Simulation: Interfacing Modelling and Simulation with Mathematical and Computational Sciences, MODSIM 2009
18th World IMACS Congress and MODSIM 2009 - International Congress on Modelling and Simulation
Interfacing Modelling and Simulation with Mathematical and Computational Sciences, Proceedings
, 4128-4134, 2020, Over-exploitation of groundwater in coastal aquifers is one of the major reasons for saltwater intrusion. Saltwater intrusion contaminates the freshwater resource in coastal aquifers by increasing the salinity levels of the groundwater. A small quantity of saltwater is enough to contaminate the large quantity of freshwater in a coastal aquifer. Therefore, saltwater intrusion should be considered seriously. Numerical models are needed to enhance the understanding of saltwater intrusion and its related phenomena extensively. The Motooka region in the Fukuoka prefecture in Japan is a coastal area, where groundwater is the main water resource for green house agriculture and domestic use. Over-exploitation of groundwater in this coastal region has resulted in saltwater intrusion and thus in the contamination of the freshwater aquifer. In addition to the more obvious effects of saltwater intrusion, fluctuations in salinity caused by such intrusion is a crucial problem to address, since even slight changes in salinity of the water use for agricultural purposes significantly affect the crop's growth and yield. So far, a research on the salinity fluctuations with groundwater pumping and their effects on seasonal recharge of groundwater in the Motooka region has not been conducted. Therefore, in this study a three-dimensional density-dependent solute transport flow model is developed to simulate the salinity fluctuations due to groundwater pumping. In the present numerical study, the emphasis is on the development of conceptual, mathematical and numerical model of variable density flow and solute transport and its application to simulate the salinity fluctuation due to groundwater pumping at different rates. The model is based on the “transition zone” approach, which considers the interface as a miscible zone where freshwater and saltwater is mixing while maintaining a density gradient across the freshwater/saltwater interface. The transition zone approach requires simultaneous solutions of the governing water flow and solute transport equations. To this end, the model incorporates three fundamental equations in flow and solute transport, namely Darcy's law, general groundwater flow equation and the advection dispersion solute transport equation. The groundwater flow equation and solute transport equation are coupled by the equation of state to produce the salt concentration at each time step for whole flow domain. The finite difference method is used as the numerical technique to solve the partial differential equations of flow and transport under an implicit scheme. The method of characteristics is applied to solve the advection term in the solute transport equation. A non-uniform discretized grid system is adopted in the flow domain allocating relatively small grid sizes to pumping well locations. To achieve reliable results, relevant and important hydro-geological parameters are assigned to the numerical model after considering the hydrological situation of the Motooka region. Different boundary conditions are assigned considering the dominant hydrological processes those are believed to be in effect in the selected area. The numerical results obtained from the model demonstrate the salinity variation due to groundwater pumping and seasonal recharge rates from year 2001 to 2007 under the influence of saltwater intrusion. The results also reveal that model is capable of correctly simulating the physical processes. A comparison of the measured and modeled electric conductivities shows reasonable agreement..
37. E. D.P. Perera, K. Jinno, Yoshinari Hiroshiro, A. Tsutsumi, Evaluation of seawater intrusion to a coastal aquifer by developing a three dimensional numerical model, International Conference on Hydrological Changes and Management from Headwaters to the Ocean, HYDROCHANGE 2008
From Headwaters to the Ocean
Hydrological Changes and Watershed Management - Proc. of the International Conference on Hydrological Changes and Management from Headwaters to the Ocean, HYDROCHAN 2008
, 231-236, 2009.12, The Motooka region in Fukuoka, Japan is a coastal region where agriculture is dominant. The green houses and wineries cover their water demand from groundwater. With the increased water demand, seawater intrusion is identified as an alarming threat to the Motooka coastal aquifer in near future. The measured electric conductivities of the water samples have been analyzed periodically. Until now the measured electric conductivities do not show high values but those values convince the emerging threat of seawater intrusion in this aquifer in future if groundwater will be pumped at current rate further. Therefore it is worth to conduct a numerical study of seawater intrusion and its impact to the Motooka area since the sustainability of the aquifer is inevitable for the future groundwater development and agriculture. In this paper a numerical study of the seawater intrusion of the Motooka is discussed. The numerical model presented in this paper was developed by coupling the groundwater flow equation with the mass transport equation to simulate the density dependent solute transport in the three dimensional space. The usage of this model as a management tool to simulate the salinity variation with groundwater pumping is emphasized. The numerical model was adequately capable of simulating the seawater intrusion and numerical results show a satisfactory agreement with the field observations..
38. E. D.P. Perera, K. Jinno, A. Tsutsumi, Y. Hiroshiro, Three dimensional solute transport numerical modeling of salinity fluctuations in a coastal aquifer, 18th World IMACS Congress and International Congress on Modelling and Simulation: Interfacing Modelling and Simulation with Mathematical and Computational Sciences, MODSIM09
18th World IMACS Congress and MODSIM09 International Congress on Modelling and Simulation
Interfacing Modelling and Simulation with Mathematical and Computational Sciences, Proceedings
, 4128-4134, 2009.12, Over-exploitation of groundwater in coastal aquifers is one of the major reasons for saltwater intrusion. Saltwater intrusion contaminates the freshwater resource in coastal aquifers by increasing the salinity levels of the groundwater. A small quantity of saltwater is enough to contaminate the large quantity of freshwater in a coastal aquifer. Therefore, saltwater intrusion should be considered seriously. Numerical models are needed to enhance the understanding of saltwater intrusion and its related phenomena extensively. The Motooka region in the Fukuoka prefecture in Japan is a coastal area, where groundwater is the main water resource for green house agriculture and domestic use. Over-exploitation of groundwater in this coastal region has resulted in saltwater intrusion and thus in the contamination of the freshwater aquifer. In addition to the more obvious effects of saltwater intrusion, fluctuations in salinity caused by such intrusion is a crucial problem to address, since even slight changes in salinity of the water use for agricultural purposes significantly affect the crop's growth and yield. So far, a research on the salinity fluctuations with groundwater pumping and their effects on seasonal recharge of groundwater in the Motooka region has not been conducted. Therefore, in this study a three-dimensional density-dependent solute transport flow model is developed to simulate the salinity fluctuations due to groundwater pumping. In the present numerical study, the emphasis is on the development of conceptual, mathematical and numerical model of variable density flow and solute transport and its application to simulate the salinity fluctuation due to groundwater pumping at different rates. The model is based on the "transition zone"approach, which considers the interface as a miscible zone where freshwater and saltwater is mixing while maintaining a density gradient across the freshwater/saltwater interface. The transition zone approach requires simultaneous solutions of the governing water flow and solute transport equations. To this end, the model incorporates three fundamental equations in flow and solute transport, namely Darcy's law, general groundwater flow equation and the advection dispersion solute transport equation. The groundwater flow equation and solute transport equation are coupled by the equation of state to produce the salt concentration at each time step for whole flow domain. The finite difference method is used as the numerical technique to solve the partial differential equations of flow and transport under an implicit scheme. The method of characteristics is applied to solve the advection term in the solute transport equation. A non-uniform discretized grid system is adopted in the flow domain allocating relatively small grid sizes to pumping well locations. To achieve reliable results, relevant and important hydro-geological parameters are assigned to the numerical model after considering the hydrological situation of the Motooka region. Different boundary conditions are assigned considering the dominant hydrological processes those are believed to be in effect in the selected area. The numerical results obtained from the model demonstrate the salinity variation due to groundwater pumping and seasonal recharge rates from year 2001 to 2007 under the influence of saltwater intrusion. The results also reveal that model is capable of correctly simulating the physical processes. A comparison of the measured and modeled electric conductivities shows reasonable agreement..
39. 松本大毅,広城吉成,神野健二,堤 敦, 地下水流動計算と放射性同位体を用いた地下水・表流水交流解析, 水文・水資源学会誌, 第22巻,第4号,pp.286-293,2009年7月, 2009.07.
40. M. A. Halim, R. K. Majumder, S. A. Nessa, K. Oda, Y. Hiroshiro, B. B. Saha, S. M. Hassain, Sk A. Latif, M. A. Islam, K. Jinno, Groundwater contamination with arsenic in Sherajdikhan, Bangladesh
Geochemical and hydrological implications, Environmental Geology, 10.1007/s00254-008-1493-8, 58, 1, 73-84, 2009.07, [URL], An integrated study has been carried out to elucidate the distribution and occurrence of arsenic in selected groundwater samples in the area of Sherajdikhan, Bangladesh. Arsenic and other parameters (T, pH, EC, Na +, K+, Ca2+, Mg2+, Cl-, NO3 -, SO4 2-, HCO3 -, PO4 3-, Fe, Mn and DOC) have been measured in groundwater samples collected from shallow/deep tube wells at different depths. Hydrogeochemical data suggest that the groundwaters are generally Ca-Mg-HCO3 and Mg-Ca-HCO3 types with bicarbonate (HCO 3 -) as the dominant anion, though the other type of water has also been observed. Dissolved arsenic in groundwater ranged from 0.006 to 0.461 mg/l, with 69% groundwater samples exceeded the Bangladesh limit for safe drinking water (0.05 mg/l). Correlation and principal component analysis have been performed to find out possible relationships among the examined parameters in groundwater. Low concentrations of NO3 - and SO 4 2-, and high concentrations of DOC, HCO3 - and PO4 3- indicate the reducing condition of subsurface aquifer where sediments are deposited with abundant organic matter. Distinct relationship of As with Fe and Mn, and strong correlation with DOC suggests that the biodegradation of organic matter along with reductive dissolution of Fe-Mn oxyhydroxides has being considered the dominant process to release As in the aquifers studied herein..
41. Abdur Razzak, Kenji Jinno, Yoshinari Hiroshiro, Md Abdul Halim, Keita Oda, Mathematical modeling of biologically mediated redox processes of iron and arsenic release in groundwater, Environmental Geology, 10.1007/s00254-008-1517-4, 58, 3, 459-469, 2009.07, [URL], A one dimensional reactive transport model was developed in order to illustrate the biogeochemical behavior of arsenic and iron reduction and release to groundwater that accounts for the reaction coupling the major redox elements under reducing environment. Mass transport equation and the method of characteristics were used considering fundamental geochemical processes to simulate transport processes of different pollutants in mobile phase. The kinetic sub-model describes the heterotrophic metabolisms of several microorganisms. To model a complete redox sequence (aerobic or denitrifiers, Fe(III)-reduction, respiration bacteria of iron and arsenic compounds, and As(V) reduction) four functional bacterial groups (X1, X2, X3, and X4) were defined. Microbial growth was assumed to follow Monod type kinetics. The exchange between the different phases (mobile, bio, and matrix) was also considered in this approach. Results from a soil column experiment were used to verify the simulation results of the model. The model depicts the utilization of oxygen, nitrate, iron oxide and arsenic as electron acceptors for oxidation of organic carbon (OC) in a column. The OC as electron donor is one of the most important factors that affect the iron and arsenic reduction bacterial activity..
42. M. A. Halim, R. K. Majumder, S. A. Nessa, K. Oda, Y. Hiroshiro, B. B. Saha, S. M. Hassain, Sk A. Latif, M. A. Islam, K. Jinno, Groundwater contamination with arsenic in Sherajdikhan, Bangladesh
Geochemical and hydrological implications, Environmental Geology, 10.1007/s00254-008-1493-8, 58, 1, 73-84, 2009.07, [URL], An integrated study has been carried out to elucidate the distribution and occurrence of arsenic in selected groundwater samples in the area of Sherajdikhan, Bangladesh. Arsenic and other parameters (T, pH, EC, Na +, K+, Ca2+, Mg2+, Cl-, NO3 -, SO4 2-, HCO3 -, PO4 3-, Fe, Mn and DOC) have been measured in groundwater samples collected from shallow/deep tube wells at different depths. Hydrogeochemical data suggest that the groundwaters are generally Ca-Mg-HCO3 and Mg-Ca-HCO3 types with bicarbonate (HCO 3 -) as the dominant anion, though the other type of water has also been observed. Dissolved arsenic in groundwater ranged from 0.006 to 0.461 mg/l, with 69% groundwater samples exceeded the Bangladesh limit for safe drinking water (0.05 mg/l). Correlation and principal component analysis have been performed to find out possible relationships among the examined parameters in groundwater. Low concentrations of NO3 - and SO 4 2-, and high concentrations of DOC, HCO3 - and PO4 3- indicate the reducing condition of subsurface aquifer where sediments are deposited with abundant organic matter. Distinct relationship of As with Fe and Mn, and strong correlation with DOC suggests that the biodegradation of organic matter along with reductive dissolution of Fe-Mn oxyhydroxides has being considered the dominant process to release As in the aquifers studied herein..
43. Abdur Razzak, Kenji Jinno, Yoshinari Hiroshiro, Md Abdul Halim, Keita Oda, Mathematical modeling of biologically mediated redox processes of iron and arsenic release in groundwater, Environmental Geology, 10.1007/s00254-008-1517-4, 58, 3, 459-469, 2009.07, [URL], A one dimensional reactive transport model was developed in order to illustrate the biogeochemical behavior of arsenic and iron reduction and release to groundwater that accounts for the reaction coupling the major redox elements under reducing environment. Mass transport equation and the method of characteristics were used considering fundamental geochemical processes to simulate transport processes of different pollutants in mobile phase. The kinetic sub-model describes the heterotrophic metabolisms of several microorganisms. To model a complete redox sequence (aerobic or denitrifiers, Fe(III)-reduction, respiration bacteria of iron and arsenic compounds, and As(V) reduction) four functional bacterial groups (X1, X2, X3, and X4) were defined. Microbial growth was assumed to follow Monod type kinetics. The exchange between the different phases (mobile, bio, and matrix) was also considered in this approach. Results from a soil column experiment were used to verify the simulation results of the model. The model depicts the utilization of oxygen, nitrate, iron oxide and arsenic as electron acceptors for oxidation of organic carbon (OC) in a column. The OC as electron donor is one of the most important factors that affect the iron and arsenic reduction bacterial activity..
44. M. A. Halim, R. K. Majumder, S. A. Nessa, Y. Hiroshiro, M. J. Uddin, J. Shimada, K. Jinno, Hydrogeochemistry and arsenic contamination of groundwater in the Ganges Delta Plain, Bangladesh, Journal of Hazardous Materials, 10.1016/j.jhazmat.2008.09.046, 164, 2-3, 1335-1345, 2009.05, [URL], Geochemical composition and the level of Arsenic (As) contamination of groundwater in the Ganges Delta Plain, southwestern Bangladesh were elucidated. Hydrogeochemical data of tube well samples suggested that the groundwater is mostly Ca-Mg-HCO3 type with bicarbonate (HCO3-) as the dominant anion, though other type waters are also observed. In contrast, the elevated EC, Cl- and high content of Na+ relative to Ca2+, Mg2+ and K+ in six groundwater samples suggest their saline origin. Low concentrations of NO3- and SO42-, and high concentrations of dissolved organic carbon (DOC), HCO3- and PO43- indicate the reducing conditions of subsurface aquifer where sediments are deposited with abundant organic matter. The total As concentration in the analyzed samples is very high (0.0431-1.352 mg/L) along with high Fe (2.791-17.058 mg/L) and relatively low Mn (0.134-1.972 mg/L) at different depths. Distinct relationship of As with Fe and Mn, and strong correlation with DOC suggests that the biodegradation of organic matter and reductive dissolution of Fe-oxyhydroxide is considered to be the dominant processes to release As in aquifers. Moreover, negative correlation between As and SO42- demonstrates the As may not be directly mobilized from sulfide minerals like arsenopyrite..
45. M. A. Halim, R. K. Majumder, S. A. Nessa, Y. Hiroshiro, M. J. Uddin, J. Shimada, K. Jinno, Hydrogeochemistry and arsenic contamination of groundwater in the Ganges Delta Plain, Bangladesh, Journal of Hazardous Materials, 10.1016/j.jhazmat.2008.09.046, 164, 2-3, 1335-1345, 2009.05, [URL], Geochemical composition and the level of Arsenic (As) contamination of groundwater in the Ganges Delta Plain, southwestern Bangladesh were elucidated. Hydrogeochemical data of tube well samples suggested that the groundwater is mostly Ca-Mg-HCO3 type with bicarbonate (HCO3-) as the dominant anion, though other type waters are also observed. In contrast, the elevated EC, Cl- and high content of Na+ relative to Ca2+, Mg2+ and K+ in six groundwater samples suggest their saline origin. Low concentrations of NO3- and SO42-, and high concentrations of dissolved organic carbon (DOC), HCO3- and PO43- indicate the reducing conditions of subsurface aquifer where sediments are deposited with abundant organic matter. The total As concentration in the analyzed samples is very high (0.0431-1.352 mg/L) along with high Fe (2.791-17.058 mg/L) and relatively low Mn (0.134-1.972 mg/L) at different depths. Distinct relationship of As with Fe and Mn, and strong correlation with DOC suggests that the biodegradation of organic matter and reductive dissolution of Fe-oxyhydroxide is considered to be the dominant processes to release As in aquifers. Moreover, negative correlation between As and SO42- demonstrates the As may not be directly mobilized from sulfide minerals like arsenopyrite..
46. Md. Abdul Halim, Ratan K. Majumder, Syeda Afsarun Nessa, Keita Oda, Yoshinari Hiroshiro, Kenji Jinno, Arsenic in shallow aquifer in the eastern region of Bangladesh: Insights from principal component analysis of groundwater compositions, Environmental Monitoring and Assessment, DOI:10.1007/s10661-009-0760-9,Vol.152,No.1, 2009.03.
47. 小田圭太,広城吉成,M.A.Halim,神野健二, バングラデシュの地下水におけるヒ素溶出特性と関連化学種との統計解析, 土木学会水工学論文集, 第53巻,p.553-558, 2009.02.
48. 横田いずみ,井料隆太,井芹慶彦,広城吉成,神野健二, 自己組織化マップを用いた福岡市民の水に関するアンケート調査結果分析, 土木学会水工学論文集, 第53巻,p.553-558, 2009.02.
49. E. D.P. Perera, K. Jinno, A. Tsutsumi, Y. Hiroshiro, Numerical study of salinity variation in a coastal aquifer
A case study of the Motooka region in western Japan, Stochastic Environmental Research and Risk Assessment, 10.1007/s00477-008-0279-6, 23, 7, 957-965, 2009.01, [URL], The Motooka region in the Fukuoka prefecture in western Japan is a coastal area, where groundwater is utilized as the main water resource for greenhouse agriculture and domestic use. Over-exploitation of groundwater has resulted in seawater intrusion and thus in the contamination of the freshwater aquifer. Fluctuations in electric conductivities caused by such intrusion are a crucial problem, since even slight changes in electric conductivities of the water used for agricultural purposes significantly affect the crops' growth and yield. However, no study has thus far been conducted on the electric conductivity fluctuations caused by groundwater pumping and seasonal recharge of groundwater in the Motooka region. To this end, an attempt is made in the present study to develop a numerical variable-density solute transport model and then apply it to simulate the electric conductivity fluctuations with groundwater pumping and rainwater recharge. This model is developed under a finite difference scheme, and the method of characteristics is used as the numerical technique for solving the advection term of the advection-dispersion solute transport equation. The results from this numerical model are compared with the field measurements..
50. E. D.P. Perera, K. Jinno, A. Tsutsumi, Y. Hiroshiro, Numerical study of salinity variation in a coastal aquifer
A case study of the Motooka region in western Japan, Stochastic Environmental Research and Risk Assessment, 10.1007/s00477-008-0279-6, 23, 7, 957-965, 2009.01, [URL], The Motooka region in the Fukuoka prefecture in western Japan is a coastal area, where groundwater is utilized as the main water resource for greenhouse agriculture and domestic use. Over-exploitation of groundwater has resulted in seawater intrusion and thus in the contamination of the freshwater aquifer. Fluctuations in electric conductivities caused by such intrusion are a crucial problem, since even slight changes in electric conductivities of the water used for agricultural purposes significantly affect the crops' growth and yield. However, no study has thus far been conducted on the electric conductivity fluctuations caused by groundwater pumping and seasonal recharge of groundwater in the Motooka region. To this end, an attempt is made in the present study to develop a numerical variable-density solute transport model and then apply it to simulate the electric conductivity fluctuations with groundwater pumping and rainwater recharge. This model is developed under a finite difference scheme, and the method of characteristics is used as the numerical technique for solving the advection term of the advection-dispersion solute transport equation. The results from this numerical model are compared with the field measurements..
51. M. Katsuki, J. Yasumoto, A. Tsutsumi, Yoshinari Hiroshiro, K. Jinno, Estimation of groundwater discharge to the sea using a distributed recharge model, International Conference on Hydrological Changes and Management from Headwaters to the Ocean, HYDROCHANGE 2008
From Headwaters to the Ocean: Hydrological Changes and Watershed Management - Proc. of the International Conference on Hydrological Changes and Management from Headwaters to the Ocean, HYDROCHAN 2008
, 625-630, 2009, Groundwater discharge to sea areas affects environmental conditions along coasts. Enclosed bays may experience eutrophication caused by nutrient input from land areas through groundwater discharge since groundwater is often contaminated by large amounts of nutrients as compared with river water. Therefore, it is necessary to estimate the groundwater discharge into seas quantitatively in order to understand nutrient pathways. A distributed groundwater recharge model was developed in order to estimate total groundwater discharge flow into the Ariake Bay, in Kyushu, Japan. The Komoda catchment within the Kikuchi River basin in Kumamoto prefecture was studied as a representative area for the Ariake Bay. The model partitions rainfall into direct runoff, evapotranspiration, and groundwater recharge. Parameters are set based on land use. Groundwater discharge is calculated using a water balance approach. The results show that groundwater discharge into the Ariake Bay from Kukuchi River basin is on average 123 mm year-1. The groundwater discharge accounts for about 8% of total water discharge and 9% of river discharge. The results can be used to better estimate annual transport of nutrients in the groundwater to the sea and thus also to better manage eutrophication problems..
52. M. Katsuki, J. Yasumoto, A. Tsutsumi, Yoshinari Hiroshiro, K. Jinno, Estimation of groundwater discharge to the sea using a distributed recharge model, International Conference on Hydrological Changes and Management from Headwaters to the Ocean, HYDROCHANGE 2008
From Headwaters to the Ocean: Hydrological Changes and Watershed Management - Proc. of the International Conference on Hydrological Changes and Management from Headwaters to the Ocean, HYDROCHAN 2008
, 625-630, 2009, Groundwater discharge to sea areas affects environmental conditions along coasts. Enclosed bays may experience eutrophication caused by nutrient input from land areas through groundwater discharge since groundwater is often contaminated by large amounts of nutrients as compared with river water. Therefore, it is necessary to estimate the groundwater discharge into seas quantitatively in order to understand nutrient pathways. A distributed groundwater recharge model was developed in order to estimate total groundwater discharge flow into the Ariake Bay, in Kyushu, Japan. The Komoda catchment within the Kikuchi River basin in Kumamoto prefecture was studied as a representative area for the Ariake Bay. The model partitions rainfall into direct runoff, evapotranspiration, and groundwater recharge. Parameters are set based on land use. Groundwater discharge is calculated using a water balance approach. The results show that groundwater discharge into the Ariake Bay from Kukuchi River basin is on average 123 mm year-1. The groundwater discharge accounts for about 8% of total water discharge and 9% of river discharge. The results can be used to better estimate annual transport of nutrients in the groundwater to the sea and thus also to better manage eutrophication problems..
53. M. Katsuki, J. Yasumoto, A. Tsutsumi, Y. Hiroshiro & K. Jinno, Estimation of groundwater discharge to the sea using a distributed recharge model, HYDROLOGICAL CHANGES AND WATERSHED MANAGEMENT, Taylor & Francis Group, London, ISBN 978-0-415-47279-1, 2008.11.
54. K. Jinno, T. Hosokawa, K. Akagi, Y. Hiroshiro, J. Yasumoto, Geochemical processes and their modelling at the fresh and salt water mixing zone, International Conference on Calibration and Reliability in Groundwater Modelling: Credibility of Modelling, ModelCARE2007
Proceedings of an International Conference on Calibration and Reliability in Groundwater Modelling
Credibility of Modelling, ModelCARE2007
, 191-196, 2008.11, Oxidation-reduction geochemical processes coupled with mass transport in a coastal aquifer is a unique subsurface environmental phenomenon to model. When a porous material is contaminated by organic carbons, nitrate is denitrified and manganese dioxide and oxi-iron hydroxide would be reduced. However, it is expected that the reduced divalent iron is oxidized once again by seawater when discharged to the sea. The paper discusses a numerical model of transport and geochemical reaction processes along the mixing zone of fresh and reduced salt water in a coastal aquifer. By comparing the numerical solution with experimental observations for the precipitation of divalent iron along the mixing zone, the validity of the model is demonstrated..
55. K. Jinno, T. Hosokawa, K. Akagi, Y. Hiroshiro, J. Yasumoto, Geochemical processes and their modelling at the fresh and salt water mixing zone, International Conference on Calibration and Reliability in Groundwater Modelling: Credibility of Modelling, ModelCARE2007
Proceedings of an International Conference on Calibration and Reliability in Groundwater Modelling
Credibility of Modelling, ModelCARE2007
, 191-196, 2008.11, Oxidation-reduction geochemical processes coupled with mass transport in a coastal aquifer is a unique subsurface environmental phenomenon to model. When a porous material is contaminated by organic carbons, nitrate is denitrified and manganese dioxide and oxi-iron hydroxide would be reduced. However, it is expected that the reduced divalent iron is oxidized once again by seawater when discharged to the sea. The paper discusses a numerical model of transport and geochemical reaction processes along the mixing zone of fresh and reduced salt water in a coastal aquifer. By comparing the numerical solution with experimental observations for the precipitation of divalent iron along the mixing zone, the validity of the model is demonstrated..
56. M. A. Halim, R. K. Majumder, S. A. Nessa, K. Oda, Y. Hiroshiro, B.B. Saha, S. M. Hassain, Sk. A. Latif, M. A. Islam, Kenji Jinno, Hydrogeochemistry and Arsenic Contamination of Groundwater in the Ganges Delta Plain, Bangladesh, Journal of Hazardous Materials, ELSEVIER, DOI:101016/j_jhazmat.2008.09.046, 2008.10.
57. Abdur Razzak, Kenji Jinno, Yoshinari Hiroshiro, Md. Abdul Halim, Keita Oda, Mathematical modeling of biologically mediated redox processes of iron and arsenic release in groundwater, Environmental Geology, DOI 10.1007/s00254-008-1517-4, Springer-Verlag, 2008.08.
58. E. D. P. Perera, K. Jinno, A. Tsutsumi & Y. Hiroshiro, Numerical study of salinity variation in a coastal aquifer: a case study of the Motooka region in western Japan, Stoch. Environ. Res. Risk Assess, Springer- Verlag, DOI 10.1007/s00477-008-0279-6, 2008.08.
59. E. D. P. PERERA, Kenji JINNO, Atsushi TSUTSUMI , Yoshinari HIROSHIRO, Development and Verification of a Three Dimensional Density-Dependent Solute Transport Model for Seawater Intrusion, MEMOIRS OF THE FACULTY OF ENGINEERING KYUSHU UNIVERSITY, Vol.68, No.2, 2008.07.
60. Md. Abdul Halim, Kenji Jinno, Abdur Razzak, Keita Oda, Yoshinari Hiroshiro, EXPERIMENTAL AND BIOGEOCHEMICAL MODELING STUDIES ON ARSENIC RELEASE IN SOIL UNDER ANAEROBIC CONDITION, The International Journal of Soil, Sediment and Water, Vol.1, No.2, ISSN:1940-3259, 2008.07.
61. M. A. Halim, R. K. Majumder, S. A. Nessa, K. Oda, Y. Hiroshiro, B.B. Saha, S. M. Hassain, Sk. A. Latif, M. A. Islam, Kenji Jinno, Groundwater contamination with arsenic in Sherajdikhan, Bangladesh: geochemical and hydrological implications, Environmental Geology, DOI 10.1007/s00254-008-1493-8, Springer-Verlag, 2008.07.
62. Kenji JINNO, Tosao HOSOKAWA, Yoshinari HIROSHIRO, Jun YASUMOTO, Geochemical Processes and their Modeling at the Fresh and Salt Water Mixing Zone, IAHS, IAHS Publ. No.312, 191-196, 2008.06.
63. Edangodage Duminda Pradeep Perera, Kenji Jinno, Atsushi Tsutsumi, Yoshinari Hiroshiro, Development and verification of a three dimensional density dependent solute transport model for seawater intrusion, Memoirs of the Faculty of Engineering, Kyushu University, 68, 2, 93-106, 2008.06, Seawater intrusion is identified as a critical issue that needs to be addressed in coastal hydrology, due its irreversible effect on the water quality of coastal freshwater aquifers. Due to the density differences in seawater and freshwater, the density dependent flow phenomenon is dominant seawater intrusion. Three dimensional numerical model is necessary to address the complex hydro-geological formations. Therefore, it is important to develop a three dimensional simulation model to understand the density dependent solute transport process taking place in the seawater intrusion problem. The model developed in this study is based on the transition zone approach which couples the groundwater flow and mass transport equation to solve the density dependent flow. The finite difference method is used as the numerical method to solve the partial difference equations of groundwater flow and solute transport. The method of characteristic is applied to solve the advection term of mass transport equation. Therefore, in this paper, a valued attempt has been taken to simulate the seawater intrusion in the three dimensional point of view under the density dependent flow effect. Motooka area of Fukuoka Prefecture Japan which is a coastal area is selected as an application area for the developed model to emphasize seawater intrusion and justify the model. This area is affected by seawater intrusion and so far numerical study of seawater intrusion under the density dependent flow concept has not performed..
64. Edangodage Duminda Pradeep Perera, Kenji Jinno, Atsushi Tsutsumi, Yoshinari Hiroshiro, Development and verification of a three dimensional density dependent solute transport model for seawater intrusion, Memoirs of the Faculty of Engineering, Kyushu University, 68, 2, 93-106, 2008.06, Seawater intrusion is identified as a critical issue that needs to be addressed in coastal hydrology, due its irreversible effect on the water quality of coastal freshwater aquifers. Due to the density differences in seawater and freshwater, the density dependent flow phenomenon is dominant seawater intrusion. Three dimensional numerical model is necessary to address the complex hydro-geological formations. Therefore, it is important to develop a three dimensional simulation model to understand the density dependent solute transport process taking place in the seawater intrusion problem. The model developed in this study is based on the transition zone approach which couples the groundwater flow and mass transport equation to solve the density dependent flow. The finite difference method is used as the numerical method to solve the partial difference equations of groundwater flow and solute transport. The method of characteristic is applied to solve the advection term of mass transport equation. Therefore, in this paper, a valued attempt has been taken to simulate the seawater intrusion in the three dimensional point of view under the density dependent flow effect. Motooka area of Fukuoka Prefecture Japan which is a coastal area is selected as an application area for the developed model to emphasize seawater intrusion and justify the model. This area is affected by seawater intrusion and so far numerical study of seawater intrusion under the density dependent flow concept has not performed..
65. Abdur RAZZAK, Kenji JINNO, Yoshinari HIROSHIRO, Md. Abdul HALIM and Keita ODA, Transport Model for Sequential Release of Mn, Fe and As under Anaerobic Soil Water Environment, MEMOIRS OF THE FACULTY OF ENGINEERING KYUSHU UNIVERSITY, Vol.68, No.1, pp.43-59, 2008.03.
66. Abdur Razzak, Kenji Jinno, Yoshinari Hiroshiro, Md Abdul Halim, Keita Oda, Transport model for sequential release of Mn, Fe and As under anaerobic soil water environment, Memoirs of the Faculty of Engineering, Kyushu University, 68, 1, 43-59, 2008.03, Groundwater contamination has been rising as a critical issue to be solved. Prediction of distribution and fate of different contaminants need to be obtained prior to designing an appropriate monitoring and remediation scheme. To model bacteria mediated redox processes a one-dimensional, multi-component reactive transport model that accounts for the reaction coupling the major redox elements was presented. Mass transport equation was used to simulate transport processes of different pollutants. For the numerical modelling of mass transport in the mobile phase, the method of characteristics was used considering fundamental geochemical processes. Then, solute transport was coupled to microbially mediated organic carbon degradation. To model a complete redox sequence (aerobic or denitrifiers, Mn(IV)-reduction, Fe(III)-reduction, respiration bacteria of iron and arsenic compounds, and As(V) reduction) five functional bacterial groups (X1, X2, X3, X 4 and X5) were defined. Microbial growth was assumed to follow Monod type kinetics. The exchange between the different phases (mobile, bio, and matrix) was also considered in this approach. Results from a soil column experiment were used to verify the simulation results of the model. It was concluded that the transport model provides a useful framework for predicting the transport of arsenic in the groundwater aquifer..
67. Abdur Razzak, Kenji Jinno, Yoshinari Hiroshiro, Md Abdul Halim, Keita Oda, Transport model for sequential release of Mn, Fe and As under anaerobic soil water environment, Memoirs of the Faculty of Engineering, Kyushu University, 68, 1, 43-59, 2008.03, Groundwater contamination has been rising as a critical issue to be solved. Prediction of distribution and fate of different contaminants need to be obtained prior to designing an appropriate monitoring and remediation scheme. To model bacteria mediated redox processes a one-dimensional, multi-component reactive transport model that accounts for the reaction coupling the major redox elements was presented. Mass transport equation was used to simulate transport processes of different pollutants. For the numerical modelling of mass transport in the mobile phase, the method of characteristics was used considering fundamental geochemical processes. Then, solute transport was coupled to microbially mediated organic carbon degradation. To model a complete redox sequence (aerobic or denitrifiers, Mn(IV)-reduction, Fe(III)-reduction, respiration bacteria of iron and arsenic compounds, and As(V) reduction) five functional bacterial groups (X1, X2, X3, X 4 and X5) were defined. Microbial growth was assumed to follow Monod type kinetics. The exchange between the different phases (mobile, bio, and matrix) was also considered in this approach. Results from a soil column experiment were used to verify the simulation results of the model. It was concluded that the transport model provides a useful framework for predicting the transport of arsenic in the groundwater aquifer..
68. 広城吉成,小田圭太,Md. Abdul HALIM,Abdur RAZZAK,神野健二, 酸化還元環境変化に伴うヒ素-鉄の化学的相互作用, 地下水学会誌, 第50巻,第1号,pp.25-32, 2008.02.
69. 横溝理恵,広城吉成,神野健二, 地下環境下における岩石-水相互作用による酸化還元機構, 土木学会水工学論文集, 第52巻,pp.421-426, 2008.02.
70. Edangodagee D. P. Perera, K. Jinno, A. Tsutsumi, Y. Hiroshiro, Simulation of Saltwater Intrusion caused Electric Conductivity Fluctuations due to Groundwater Pumping in a Coastal Aquifer, International Congress on Modelling and Simulation, CD-ROM,1582-1588, 2007.12.
71. Kenji JINNO, Tosao HOSOKAWA, Yoshinari HIROSHIRO, Jun YASUMOTO, Geochemical Processes and their Modeling at the Fresh and Salt Water Mixing Zone, ModelCARE2007(IAHS), pp.350~355, 2007.09.
72. 広城吉成,赤木啓悟,細川土佐男,神野健二, 沿岸部帯水層の塩水遷移域における二価鉄イオンの動態に着目した輸送モデル, 土木学会論文集B, Vol.63, No.3, pp.178-188, 2007.07.
73. Jun YASUMOTO, Mamoru KATSUKI, Hidetomo TAKAOKA, Yoshinari HIROSHIRO, Kenji JINNO, Nutrient Inputs through Submarine Groundwater Discharge to Ariake Bay, Kyushu Island, Japan, IAHS(International Association of Hydrological Sciences), No.312, 159-168, 2007.07.
74. Othoman Ahmad ALKAEED, Atsushi TSUTSUMI, Kenji JINNO and Yoshinari HIROSHIRO, Application of a Groundwater Recharge Model for Estimating Surface Runoff Components in Sakurai River Watershed, Fukuoka, Japan, Proc. of 32nd Congress IAHR, CD-ROM, 2007.07.
75. Othoman Ahmad ALKAEED, Atsushi TSUTSUMI, Kenji JINNO, Yoshinari Hiroshiro, Using the Separation of Rainwater by the Groundwater Model to Estimate Surface Runoff and Groundwater Infiltration Rate, Proceedings of International Workshop on Earth Resources Technology, p.47-52, 2007.04.
76. Yoshinari Hiroshiro, Kenji Jinno, Atsushi Tsutsumi, Masataka Matsumoto, Ronny Berndtsson, Estimation of Residence Time and Catchment Area for Spring Water Using Radioactive Isotope and Groundwater Flow Model, MEMOIRS OF THE FACULTY OF ENGINEERING KYUSHU UNIVERSITY, Vol.67, No.1, pp.1-9, 2007.03.
77. Othoman Ahmad ALKAEED, Atsushi TSUTSUMI, Kenji JINNO, Yoshinari Hiroshiro, Estimation of Surface Runoff and Groundwater Infiltration Components By the Groundwater Recharge Model (Itoshima Area, Japan), MEMOIRS OF THE FACULTY OF ENGINEERING KYUSHU UNIVERSITY, Vol.67, No.1, pp.11-23, 2007.03.
78. Yoshinari Hiroshiro, Kenji Jinno, Atsushi Tsutsumi, Masataka Matsumoto, Ronny Berndtsson, Estimation of residence time and catchment area for spring water using radioactive isotope and groundwater flow model, Memoirs of the Faculty of Engineering, Kyushu University, 67, 1, 1-9, 2007.03, Spring water, however, is often formed in complex geological formations and therefore it is difficult to determine the catchment area contributing to the flow. The Sayanokami spring, located in western part of Fukuoka City, Japan, is such a spring and an important water resource for the local agriculture. In order to better understand the hydrological properties of infiltration and groundwater processes for the spring water, 222Rn and tritium were used as tracers. Results showed that the residence time for the spring water is 10 - 20 years. A groundwater model confirmed these results and the travel time from the catchment border estimated to be about 25 years. Using this information the catchment border and uptake area were estimated. The method can be used to more efficiently determine catchment area and travel time for groundwater and thus to better manage the spring water..
79. Othoman Ahmad Alkaeed, Atsushi Tsutsumi, Kenji Jinno, Yoshinari Hiroshiro, Estimation of surface runoff and groundwater infiltration components by the groundwater recharge model (itoshima area, Japan), Memoirs of the Faculty of Engineering, Kyushu University, 67, 1, 11-23, 2007.03, This paper presents the estimation of the parameters F, and (r)1/2 used in the groimdwater recharge model by separating the surface runoff component for isolated rainfall event. The time-area distribution method was used. Several types of land use were considered. The watershed of the upstream of Sakurai River at Suematsu Bridge in Itoshlma Peninsula which includes the western part of the new campus (Ito campus) area of Kyushu University in southern Japan, was selected as a site study to test the model approach. Since more than 80% of study area is covered with forest, the proposed model considers rainfall interception by forest canopy. The runoff parameters F and (r)1/2 were identified in this study using records of river discharge at the outlet point of the watershed. The results indicate that the separation approach satisfactorily predicted runoff parameters for different land use, and also showed that simulated runoff results agree well with observed results..
80. Yoshinari Hiroshiro, Kenji Jinno, Atsushi Tsutsumi, Masataka Matsumoto, Ronny Berndtsson, Estimation of residence time and catchment area for spring water using radioactive isotope and groundwater flow model, Memoirs of the Faculty of Engineering, Kyushu University, 67, 1, 1-9, 2007.03, Spring water, however, is often formed in complex geological formations and therefore it is difficult to determine the catchment area contributing to the flow. The Sayanokami spring, located in western part of Fukuoka City, Japan, is such a spring and an important water resource for the local agriculture. In order to better understand the hydrological properties of infiltration and groundwater processes for the spring water, 222Rn and tritium were used as tracers. Results showed that the residence time for the spring water is 10 - 20 years. A groundwater model confirmed these results and the travel time from the catchment border estimated to be about 25 years. Using this information the catchment border and uptake area were estimated. The method can be used to more efficiently determine catchment area and travel time for groundwater and thus to better manage the spring water..
81. Othoman Ahmad Alkaeed, Atsushi Tsutsumi, Kenji Jinno, Yoshinari Hiroshiro, Estimation of surface runoff and groundwater infiltration components by the groundwater recharge model (itoshima area, Japan), Memoirs of the Faculty of Engineering, Kyushu University, 67, 1, 11-23, 2007.03, This paper presents the estimation of the parameters F, and (r)1/2 used in the groimdwater recharge model by separating the surface runoff component for isolated rainfall event. The time-area distribution method was used. Several types of land use were considered. The watershed of the upstream of Sakurai River at Suematsu Bridge in Itoshlma Peninsula which includes the western part of the new campus (Ito campus) area of Kyushu University in southern Japan, was selected as a site study to test the model approach. Since more than 80% of study area is covered with forest, the proposed model considers rainfall interception by forest canopy. The runoff parameters F and (r)1/2 were identified in this study using records of river discharge at the outlet point of the watershed. The results indicate that the separation approach satisfactorily predicted runoff parameters for different land use, and also showed that simulated runoff results agree well with observed results..
82. 安元 純,広城吉成,高岡秀朋,古市久士,松原英隆,神野健二, 有明海沿岸域の佐賀県太良町大浦沖における海底地下水湧出と栄養塩の輸送, 水工学論文集, 第51巻,pp.481 -485, 2007.02.
83. 石橋純一郎,小川啓太,瀬口真理子、島田允堯,池見洋明,広城吉成, 福岡市西区・九州大学伊都キャンパス地区の岩脈年代と地下水の化学組成, 九州大学大学院理学研究院研究報告地球惑星科学, 第22巻,第2号,p.63-74, 2007.02.
84. Jun Ichiro Ishibashi, Keita Ogawa, Mariko Seguchi, Nobutaka Shimada, Hiro Ikemi, Yoshinari Hiroshiro, K-Ar age determination of a lamprophyre dike, and geochemical features of groundwater in the Ito Campus, Kyushu University, Fukuoka, Science Reports of the Kyushu University, Department of Earth and Planetary Sciences, 22, 2, 63-74, 2007.02, Within the Ito Campus and surrounding area, subsurface investigations with several borings had been conducted by the Kyushu University. Core samples obtained by the boring and groundwater samples collected from the boring wells provide important information on understanding geological and geochemical features of this area. Age determination of a lamprophyre dike in the Itoshima Granitoid using K-Ar technique provided age of around 90.7 ± 1.2 Ma, which is in accordance with the reported age for main body of the granitoid. This result would be one of constraints for discussion on igneous activities in the northern Kyushu. The groundwater collected from this area can be classified into four types based on the chemical and isotopic compositions. The relationship between water chemistry and water elevation can be explained as a snap shot of groundwater evolution from meteoric water to the Ca-HCO3 type groundwater accompanying weathering of granitic rocks. Within the alluvial sediments in the east of the Ito Campus, the Na-Cl type groundwater is widely distributed, which is attributed to the influence of seawater intrusion. The natural flow which is associated with the West Off Fukuoka Earthquake on March 20, 2005 is explained as a result of rising of the freshwater-seawater boundary..
85. Jun Ichiro Ishibashi, Keita Ogawa, Mariko Seguchi, Nobutaka Shimada, Hiro Ikemi, Yoshinari Hiroshiro, K-Ar age determination of a lamprophyre dike, and geochemical features of groundwater in the Ito Campus, Kyushu University, Fukuoka, Science Reports of the Kyushu University, Department of Earth and Planetary Sciences, 22, 2, 63-74, 2007.02, Within the Ito Campus and surrounding area, subsurface investigations with several borings had been conducted by the Kyushu University. Core samples obtained by the boring and groundwater samples collected from the boring wells provide important information on understanding geological and geochemical features of this area. Age determination of a lamprophyre dike in the Itoshima Granitoid using K-Ar technique provided age of around 90.7 ± 1.2 Ma, which is in accordance with the reported age for main body of the granitoid. This result would be one of constraints for discussion on igneous activities in the northern Kyushu. The groundwater collected from this area can be classified into four types based on the chemical and isotopic compositions. The relationship between water chemistry and water elevation can be explained as a snap shot of groundwater evolution from meteoric water to the Ca-HCO3 type groundwater accompanying weathering of granitic rocks. Within the alluvial sediments in the east of the Ito Campus, the Na-Cl type groundwater is widely distributed, which is attributed to the influence of seawater intrusion. The natural flow which is associated with the West Off Fukuoka Earthquake on March 20, 2005 is explained as a result of rising of the freshwater-seawater boundary..
86. Abdul Halim, Kenji Jinno, Abdur Razzak, Keita Oda, Yoshinari Hiroshiro, Experimental and biogeochemical modeling studies on arsenic release in soil under anaerobic condition, 23rd Annual International Conference on Soils Sediments and Water 2007
Association for Environmental Health and Sciences - 23rd Annual International Conference on Soils, Sediments and Water 2007
, 13, 224-239, 2007, The identification of release mechanisms of arsenic may assist in designing safe and effective remediation strategies, due to its severe toxicity effect for the human body. In this regards, investigations were carried out to observe the release of As from soil into water. It was found that As concentration increased with decreasing oxidation reduction potential. Arsenic concentrations demonstrated negative covariation with the concentrations of NO3 but strongly correlated with DOC and Fe concentrations. Batch leaching tests at different pH conditions showed a strong pH dependence on arsenic and iron leaching. A numerical simulation of arsenic transport model, coupled with microbially mediated biogeochemical processes was developed for describing the release of As in soil under reducing environment. The simulation concentrations of Mn, Fe and As were well matched those found experimentally. The results of this study suggested that the microbially mediated degradation of organic matter and reductive dissolution of Fe-oxyhydroxide are considered to be the dominant processes to release As in aquifers..
87. Jun Yasumoto, Mamoru Katsuki, Hidetomo Takaoka, Yoshinari Hiroshiro, Kenji Jinno, Nutrient inputs through submarine groundwater discharge to Ariake Bay, Kyushu Island, Japan, International Symposium: A New Focus on Groundwater - Seawater Interactions - 24th General Assembly of the International Union of Geodesy and Geophysics (IUGG)
IAHS-AISH Publication - A New Focus on Groundwater - Seawater Interactions
, 159-168, 2007, Submarine groundwater discharge (SGD) is now recognized as an important pathway between land and sea. This study attempts to estimate the nutrient inputs through SGD to Ariake Bay. SGD rates and its quality along the coast of Ariake Bay in the Oura Region, Japan, were investigated. It was shown that the on-site SGD rate ranges from 0.01 to 20.52 μm/s, and SGD flows through the shallow confined aquifers, which consist of two kinds of rocks: basalt and pyroclastic rocks. The reduction reaction for SGD proceeded just up to denitrification. SGD associated with nutrient loads of N, P and SiO2 were estimated to be 1.40, 0.07 and 52.78 g m-2 d-1, respectively. This study demonstrates that SGD must be considered as a significant source of nutrient input to the coastal sea area in Ariake Bay..
88. E. D P Perera, K. Jinno, A. Tsutsumi, Yoshinari Hiroshiro, Simulation of saltwater intrusion caused electric conductivity fluctuations due to groundwater pumping in a coastal aquifer, International Congress on Modelling and Simulation - Land, Water and Environmental Management: Integrated Systems for Sustainability, MODSIM07
MODSIM07 - Land, Water and Environmental Management: Integrated Systems for Sustainability, Proceedings
, 1582-1588, 2007.
89. Abdul Halim, Kenji Jinno, Abdur Razzak, Keita Oda, Yoshinari Hiroshiro, Experimental and biogeochemical modeling studies on arsenic release in soil under anaerobic condition, 23rd Annual International Conference on Soils Sediments and Water 2007
Association for Environmental Health and Sciences - 23rd Annual International Conference on Soils, Sediments and Water 2007
, 13, 224-239, 2007, The identification of release mechanisms of arsenic may assist in designing safe and effective remediation strategies, due to its severe toxicity effect for the human body. In this regards, investigations were carried out to observe the release of As from soil into water. It was found that As concentration increased with decreasing oxidation reduction potential. Arsenic concentrations demonstrated negative covariation with the concentrations of NO3 but strongly correlated with DOC and Fe concentrations. Batch leaching tests at different pH conditions showed a strong pH dependence on arsenic and iron leaching. A numerical simulation of arsenic transport model, coupled with microbially mediated biogeochemical processes was developed for describing the release of As in soil under reducing environment. The simulation concentrations of Mn, Fe and As were well matched those found experimentally. The results of this study suggested that the microbially mediated degradation of organic matter and reductive dissolution of Fe-oxyhydroxide are considered to be the dominant processes to release As in aquifers..
90. Jun Yasumoto, Mamoru Katsuki, Hidetomo Takaoka, Yoshinari Hiroshiro, Kenji Jinno, Nutrient inputs through submarine groundwater discharge to Ariake Bay, Kyushu Island, Japan, International Symposium: A New Focus on Groundwater - Seawater Interactions - 24th General Assembly of the International Union of Geodesy and Geophysics (IUGG)
IAHS-AISH Publication - A New Focus on Groundwater - Seawater Interactions
, 159-168, 2007, Submarine groundwater discharge (SGD) is now recognized as an important pathway between land and sea. This study attempts to estimate the nutrient inputs through SGD to Ariake Bay. SGD rates and its quality along the coast of Ariake Bay in the Oura Region, Japan, were investigated. It was shown that the on-site SGD rate ranges from 0.01 to 20.52 μm/s, and SGD flows through the shallow confined aquifers, which consist of two kinds of rocks: basalt and pyroclastic rocks. The reduction reaction for SGD proceeded just up to denitrification. SGD associated with nutrient loads of N, P and SiO2 were estimated to be 1.40, 0.07 and 52.78 g m-2 d-1, respectively. This study demonstrates that SGD must be considered as a significant source of nutrient input to the coastal sea area in Ariake Bay..
91. E. D.P. Perera, K. Jinno, A. Tsutsumi, Y. Hiroshiro, Simulation of saltwater intrusion caused electric conductivity fluctuations due to groundwater pumping in a coastal aquifer, International Congress on Modelling and Simulation - Land, Water and Environmental Management: Integrated Systems for Sustainability, MODSIM07
MODSIM07 - Land, Water and Environmental Management
Integrated Systems for Sustainability, Proceedings
, 1582-1588, 2007.
92. Jun Yasumoto, Mamoru Katsuki, Hidetomo Takaoka, Yoshinari Hiroshiro, Kenji Jinno, Upscaling of groundwater flow and geochemical transport to the Ariake Bay, in Kyushu Island, Japan, Proceedings of international symposium on “International between seawater and groundwater in the coastal zone and their effect on the environmental nutrient load toward the sea”, pp.99-100, 2006.12.
93. Keigo Akagi, Tosao Hosokawa, Yoshinari Hiroshiro and Kenji Jinno, Modeling of Physical and Geochemical Behaviors of Saltwater in a Coastal Aquifer, Advances in Geosciences, Vol.4, p.251-260, 2006.06.
94. Yoshinari Hiroshiro, Kenji Jinno, Ronny Berndtsson, Hydrogeochemical properties of a salinity-affected coastal aquifer in western Japan, HYDROLOGICAL PROCESSES, Vol.20, 1425-1435, 2006.04.
95. Yoshinari Hiroshiro, Kenji Jinno, Ronny Berndtsson, Hydrogeochemical properties of a salinity-affected coastal aquifer in western Japan, Hydrological Processes, 10.1002/hyp.6099, 20, 6, 1425-1435, 2006.04, [URL], Coastal groundwater aquifers are often exposed to heavy pumping and consequently to risks of saltwater intrusion. In many cases, however, the observed increase in groundwater salinity can only be partly explained by actual saltwater intrusion from the sea. Other salinity-increasing processes may also significantly contribute to the total salt content of the groundwater. This paper describes a geochemical investigation that was carried out to investigate recent salinity increases in groundwater for the Motooka coastal area in Fukuoka, Japan. A strong increase in electrical conductivity at 15-20 m depth was observed, corresponding to the freshwater and saltwater interface. Oxidation-reduction potentials observed in deeper groundwater were low, indicating long residence time for the groundwater. These results, together with hydrogen-oxygen isotope ratio analysis, indicated that the deeper groundwater is affected by seawater. Consequently, observed tritium concentration in the shallow groundwater system was higher than that of the deeper groundwater system, and a 14C isotope dating of shell samples collected at 2 m depth indicated an age of about 2000 years. The overall results suggest that the aquifer was originally below the current sea floor and that deeper saline groundwater is not mixed with the shallower fresh groundwater. The deeper groundwater is, therefore, mainly affected by old seawater. In other words, modern saltwater intrusion has not yet occurred even if some wells contain saline water. The study shows that, even though coastal aquifers are heavily pumped, the reason for the rise in groundwater salinity may not necessarily be due to seawater intrusion. Further geochemical and hydrological investigations will be necessary to identify the underlying mechanisms..
96. Yoshinari Hiroshiro, Kenji Jinno, Ronny Berndtsson, Hydrogeochemical properties of a salinity-affected coastal aquifer in western Japan, Hydrological Processes, 10.1002/hyp.6099, 20, 6, 1425-1435, 2006.04, [URL], Coastal groundwater aquifers are often exposed to heavy pumping and consequently to risks of saltwater intrusion. In many cases, however, the observed increase in groundwater salinity can only be partly explained by actual saltwater intrusion from the sea. Other salinity-increasing processes may also significantly contribute to the total salt content of the groundwater. This paper describes a geochemical investigation that was carried out to investigate recent salinity increases in groundwater for the Motooka coastal area in Fukuoka, Japan. A strong increase in electrical conductivity at 15-20 m depth was observed, corresponding to the freshwater and saltwater interface. Oxidation-reduction potentials observed in deeper groundwater were low, indicating long residence time for the groundwater. These results, together with hydrogen-oxygen isotope ratio analysis, indicated that the deeper groundwater is affected by seawater. Consequently, observed tritium concentration in the shallow groundwater system was higher than that of the deeper groundwater system, and a 14C isotope dating of shell samples collected at 2 m depth indicated an age of about 2000 years. The overall results suggest that the aquifer was originally below the current sea floor and that deeper saline groundwater is not mixed with the shallower fresh groundwater. The deeper groundwater is, therefore, mainly affected by old seawater. In other words, modern saltwater intrusion has not yet occurred even if some wells contain saline water. The study shows that, even though coastal aquifers are heavily pumped, the reason for the rise in groundwater salinity may not necessarily be due to seawater intrusion. Further geochemical and hydrological investigations will be necessary to identify the underlying mechanisms..
97. Keigo Akagi, Tosao Hosokawa, Yoshinari Hiroshiro, Kenji Jinno, Modeling of physical and geochemical behaviors of saltwater in a coastal aquifer, Advances in Geosciences Volume 4
Hydrological Science (HS)
, 10.1142/9789812707208_0031, 251-260, 2006.01, [URL], Groundwater quality is affected by the various reactions such as precipitation of dissolved ions, solid-liquid phase interaction, and the bacteriamediated reduction-oxidation process. The geochemical properties in coastal aquifers are unique and important for the management of groundwater environment. Although the studies analyzing the hydrological behaviors have been intensively done up to now, a study of coupling both groundwater flow and geochemical analysis is limited. In this study, the one-dimensional multicomponent solute transport model which accounts for the cation exchange reaction and the reduction reaction induced by anaerobic degradation is studied. It is found out both through experiment and numerical simulation that the cation exchange process is significant at the frontal part of the seawater infiltration, while reducing process by the bacteria mediation takes places at the entire soil column except for the top of the soil where dissolved oxygen infiltrates. Saltwater intrusion into a coastal aquifer is a traditional but still important for the hydro-geologists and civil engineers even at present time. Contamination of salt is a trouble for various freshwater uses. Therefore, much attention has been put on the movement and potential contamination. Meanwhile, the geophysical study is solely carried out. However, the consistent and accurate conclusion will be hardly obtained due to the complicated and limited information on the aquifer properties. In order to get a confident conclusion that can be agreed by the researchers in various fields, an interdisciplinary approach anticipating both hydrological and geochemical processes is indispensable..
98. Keigo Akagi, Tosao Hosokawa, Yoshinari Hiroshiro, Kenji Jinno, Modeling of physical and geochemical behaviors of saltwater in a coastal aquifer, Advances in Geosciences Volume 4
Hydrological Science (HS)
, 10.1142/9789812707208_0031, 251-260, 2006.01, [URL], Groundwater quality is affected by the various reactions such as precipitation of dissolved ions, solid-liquid phase interaction, and the bacteriamediated reduction-oxidation process. The geochemical properties in coastal aquifers are unique and important for the management of groundwater environment. Although the studies analyzing the hydrological behaviors have been intensively done up to now, a study of coupling both groundwater flow and geochemical analysis is limited. In this study, the one-dimensional multicomponent solute transport model which accounts for the cation exchange reaction and the reduction reaction induced by anaerobic degradation is studied. It is found out both through experiment and numerical simulation that the cation exchange process is significant at the frontal part of the seawater infiltration, while reducing process by the bacteria mediation takes places at the entire soil column except for the top of the soil where dissolved oxygen infiltrates. Saltwater intrusion into a coastal aquifer is a traditional but still important for the hydro-geologists and civil engineers even at present time. Contamination of salt is a trouble for various freshwater uses. Therefore, much attention has been put on the movement and potential contamination. Meanwhile, the geophysical study is solely carried out. However, the consistent and accurate conclusion will be hardly obtained due to the complicated and limited information on the aquifer properties. In order to get a confident conclusion that can be agreed by the researchers in various fields, an interdisciplinary approach anticipating both hydrological and geochemical processes is indispensable..
99. 大橋伸行,広城吉成,新井田 浩,神野健二, 沿岸低地部帯水層における淡水及び塩水境界の挙動解析, 地下水学会誌, 第47巻,第2号,pp.235 -251, 2005.05.
100. 南 健太,新井田 浩,神野 健二,堤 敦,広城 吉成,下大迫博志,濱里 学,泉谷隆志, 雨水貯留浸透施設の計画・評価手法−九州大学新キャンパス建設地を対象として−, 土木学会水工学論文集, 第49巻pp.67-72, 2005.02.
101. 赤木啓悟,細川土佐男,Ginnging GUERRA,神野 健二,広城 吉成,堤 敦, 有機質土壌中に海水を浸透させた場合の陽イオン交換及び微生物による還元反応を考慮した主要イオン輸送解析, 土木学会水工学論文集, 第49巻,pp.139-144, 2005.02.
102. 松本 大毅,広城 吉成,堤 敦,神野 健二,新井田 浩, ラドンおよびトリチウムによる地球化学的手法と地下水流動計算による湧水の滞留時間と集水域の推定, 土木学会水工学論文集, 第49巻,pp.127-132, 2005.02.
103. Yoshinari HIROSHIRO, Kenji JINNO, Takushi YOKOYAMA, S.-I. WADA, and M. KUBOTA, Multicomponent solute transport model with cation exchange in a redox subsurface environment, Calibration and Reliability in Groundwater Modelling,IAHS Publ. No.265 , pp.474〜480, Sept.2000., 265, 474-480, 2000.09.
104. 広城吉成,吉本拓磨,森田 守,神野健二,和田信一郎, 下水処理水を湛水させた土壌カラム中の多成分化学種の動態, 九州大学工学集報,第73巻,第5号,pp.599〜604,2000年9月., 2000.09.
105. 広城吉成,神野健二,佐伯和利,池見洋明,岩月輝希,松岡信明,岡村正紀,田籠久也, 環境同位体による塩水化地下水の地球化学的考察, 水工学論文集第46巻,pp.205〜210,2002年2月., 2002.02.
106. 中川 啓,細川土佐男,岩満公正,神野健二,広城吉成, 汀線近傍の暗渠排水に伴う海岸帯水層中の淡水と塩水の混合挙動に関する研究, 水工学論文集第46巻,pp.181〜186,2002年2月., 2002.02.
107. 広城吉成,神野健二,中野芳輔,河村 明,森 牧人,古賀 誠司,新井田 浩, 九州大学新キャンパス統合移転事業における水循環系の保全と管理について, 第6回水資源に関するシンポジウム論文集,pp.277〜282,2002年8月., 2002.08.
108. 佐伯和利,中川 啓,和田信一郎,柴田雅博,神野健二,広城吉成, ベントナイトにおける2価鉄、マンガンイオンの関与するイオン交換平衡の選択係数, 粘土科学,第42巻,第1号,pp.1-5,2002年8月., 2002.08.
109. 広城吉成,神野健二,佐伯和利,池見洋明,呉 潤根,松岡信明,岡村正紀,田籠久也, 塩水化地下水の地球化学的水質特性-韓国・濟州島東部,千葉県長生村,福岡県津屋崎町,福岡市西区元岡-, 地下水学会誌,第44巻,第3号,pp.227〜238,2002年9月., 2002.09.
110. Kei NAKAGAWA, Tosao HOSOKAWA, Kousei IWAMITSU, Kenji JINNO, Yoshinari HIROSHIRO, Behavior of fresh and salt groundwater in a sandy coastal aquifer under the beach erosion control using pipe drains, Journal of Hydroscience and Hydraulic Engineering, Vol.20, No.2, pp.71-82, Nov. 2002, 2002.11.
111. Gingging GUERRA, Yoshinari HIROSHIRO,Kenji JINNO, Behavior of chemical species under redox conditions using multicomponent solute transport model, Annual Journal of Hydraulic Engineering, JSCE, Vol.47,pp.319~324, Feb. 2003, 2003.02.
112. 堤 敦,神野健二,森 牧人,広城吉成, 遮断降雨を考慮した雨水の地下水涵養モデル, 水工学論文集第47巻,pp.277〜282,2003年2月., 2003.02.
113. Yoshinari HIROSHIRO, Kenji JINNO, Gingging GUERRA, Teruki IWATSUKI, Nobuaki MATSUOKA, Masaki OKAMURA, Hisaya TAGOMORI, Geochemical Investigations of Salinized Groundwater Using Environmental Isotopes, Journal of Hydroscience and Hydraulic Engineering, Vol.21, No.1, 79-85, 2003., 2003.05.
114. 堤 敦,神野健二,森 牧人,広城吉成, 表流水−地下水系水循環機構の解析−九州大学新キャンパス建設地を対象として−, 土木学会論文集, No.747/II-65,29-40, 2003.11.
115. Guerra Gingging, Kenji Jinno, Yoshinari Hiroshiro, Koji Nakamura, Multi-component Solute Transport Model with Cation Exchange under Redox Environment and its Application for Designing the Slow Infiltration Setup, MEMOIRS OF THE FACULTY OF ENGINEERING KYUSHU UNIVERSITY, Vol.64, No.1, pp.79-100, 2004.03.
116. Gingging GUERRA, Kenji JINNO, Yoshinari HIROSHIRO, Numerical simulation for designing the nitrate removal by soil infiltration, Proceedings of the XVth international Conference on Computational Methods in Water Resources, ELSEVIER., 55, 925-938, 925-938, 2004.06.
117. Moshood N. TIJANI, Kenji JINNO, Yoshinari HIROSHIRO, Environmental impact of heavy metals distribution in water and sediments of Ogunpa River, Ibadan area, southwestern Nigeria, Journal of Mining and Geology, Vol.40, No.1, pp.73-83, 2004., 2004.03.
118. 松本大毅,広城吉成,新井田 浩,神野健二,岡村正紀,仲島 賢,田籠久也,右田義臣, ラドンと水質から推定される湧水周辺の水文・地球化学的特性について-福岡市西区幸の神湧水における事例-, 水文・水資源学会誌, 第17巻,第6号,pp.627-635,2004年11月., 2004.11.
119. G. Guerra, K. Jinno, Yoshinari Hiroshiro, Numerical simulation for designing the nitrate removal by soil infiltration, Developments in Water Science, 10.1016/S0167-5648(04)80112-6, 55, PART 1, 925-938, 2004.12, [URL], A multicomponent solute transport model that includes the biochemical redox reactions and cation exchange reactions was developed. It takes into consideration four different phases: pore water phase, bio phase, soil matrix phase, and solid phase. The microbially mediated sequence of reactions was modeled using Monod type equations. The model computes changes in concentration over time caused by the processes of advection, dispersion, biochemical reactions, and cation exchange reactions. A soil column experiment was conducted to determine the behavior of chemical species in aoil columns applied with secondary treated sewage water. The soil column experiment and the solute transport model had produced interesting observations on the behavior of different chemical species. The observed concentrations correlated fairly well with the simulated concentrations. The model reproduced the sequential reduction reaction. O2 was reduced first after 30 hours then followed by NO3- after 31 hours. In this study, the numerical simulation of NO3- was done using the multicomponent solute transport model to determine the effect of pore velocity and input C H2O concentration needed to reduce the NO3- leaching. It is revealed that the multicomponent solute transport model is useful to design the land, treatment system for NO3- removal from wastewater..
120. Gingging Guerra, Kenji Jinno, Yoshinari Hiroshiro, Koji Nakamura, Multi-component solute transport model with cation exchange under redox environment and its application for designing the slow infiltration setup, Memoirs of the Faculty of Engineering, Kyushu University, 64, 1, 78-100, 2004.03, The present trend of disposing treated sewage water by allowing it to infiltrate the soil brings a new dimension to environmental problems. It is therefore necessary to identify the chemicals likely to be present in treated sewage water. A soil column experiment was conducted to determine the behavior of chemical species in soil columns applied with secondary treated sewage water. To predict the behavior of chemical species, a multicomponent solute transport model that includes the biochemical redox process and cation exchange process was developed. The model computes changes in concentration over time caused by the processes of advection, dispersion, biochemical reactions and cation exchange reactions. The solute transport model was able to predict the behavior of different chemical species in the soil column applied with secondary treated sewage water. The model reproduced the sequential reduction reaction. To design the safe depth of plow layer where NO 3 - is totally reduced, a numerical study of NO 3 - leach was done and it was found out that the pore velocity and concentration of CH 2O at the inject water was found to affect NO 3 - reduction in the mobile pore water phase. It is revealed that the multicomponent solute transport model is useful to design the land treatment system for NO 3 removal from wastewater..
121. Moshood N. Tijani, Kennji Jinno, Yoshinari Hiroshiro, Environmental impact of heavy metals distribution in water and sediments of Ogunpa River, Ibadan area, southwestern Nigeria, Journal of Mining and Geology, 10.4314/jmg.v40i1.18811, 40, 1, 73-83, 2004.01, [URL], Geochemical evaluation of distribution of heavy metals in water and sediments of Ogunpa River within Ibadan metropolis in Southwestern Nigeria is presented in respect of anthropogenic contamination from the surrounding urbanized catchment area. The results revealed low contamination or enrichment of the heavy metals (Pb, Zn, Cu, Cd, and As) in the water phase. Also, the sediment phase (<63μm) of the drainage system is anthropogenically enriched in Ph, Zn, Cu, Cd, As and t-Hg with all recording an estimated anthropogenic factor (AF) value above 1. The estimated index of geoaccumulation (Igco) with a value of approximately 2 for Pb, Zn and t-Hg indicates moderate or middle level contamination in the sediments while Igco of <1 recorded for Cu, Cd, and As indicate very low or no contamination. This trend is however, reversed in the water column with Cu and Cd having Igco value of 1.2 and 3.2 respectively, pointing to relative partitioning of the metals between the two media. Quantification of degree of pollution revealed high anthropogenic contribution for Pb (75%), Zn (75%) and t-Hg (60%), indicating enrichment by a factor of at least 5 in the sediment phase, while anthropogenic in-put also accounts for 70% (Cu) and 90% (Cd) in the water column. Furthermore, correlation of electrical conductivity (EC) peaks with the high values of Pb, Zn and t-Hg indicated that the inputs are related to anthropogenic sources along the stretches of the Ogunpa channel. The sources of contamination are attributed to urbanised anthropogenic sources, mostly vehicular emissions and related repair products, domestic sewage and effluents, varied household garbages and refuse dumps including incineration bye-products. Based on the overall evaluation, recommendations in respect of sanitization and contamination control/monitoring strategies in the study area are also presented..
122. Gingging Guerra, Kenji Jinno, Yoshinari Hiroshiro, Variation of chemical species in infiltrating treated sewage water using the multi-component solute transport model, IAHS-AISH Publication, 285, 92-99, 2003.12, Due to uncertainties raised about the presence of contaminants from recycled water it is necessary to identify the chemicals likely to be present in treated sewage water, and assess approaches for minimizing their release. The relevant physical, chemical and biochemical processes must be understood in order to determine the state and movement of contaminants. To simulate the mechanisms responsible for the movement of chemical species, predictive tools in the form of mathematical models have been developed. This study deals with the processes and chemical transport in an aqueous soil similar to paddy fields where successive reduction reactions occur. To examine the behaviour of the different chemical species present in the secondary treated sewage water, a two-soil column experiment was conducted. In order to more fully understand chemical and biochemical processes, a solute transport model that takes into consideration the biochemical reactions and cation exchange reactions was developed in this study. The soil column experiment and the solute transport model produced interesting observations on the behaviour of different chemical species. The observed concentrations correlated fairly well with the simulated concentrations and the sequence of reduction reactions were reproduced by the developed solute transport model..
123. G. Guerra, K. Jinno, Yoshinari Hiroshiro, Numerical simulation for designing the nitrate removal by soil infiltration, Developments in Water Science, 10.1016/S0167-5648(04)80112-6, 55, PART 1, 925-938, 2004.12, [URL], A multicomponent solute transport model that includes the biochemical redox reactions and cation exchange reactions was developed. It takes into consideration four different phases: pore water phase, bio phase, soil matrix phase, and solid phase. The microbially mediated sequence of reactions was modeled using Monod type equations. The model computes changes in concentration over time caused by the processes of advection, dispersion, biochemical reactions, and cation exchange reactions. A soil column experiment was conducted to determine the behavior of chemical species in aoil columns applied with secondary treated sewage water. The soil column experiment and the solute transport model had produced interesting observations on the behavior of different chemical species. The observed concentrations correlated fairly well with the simulated concentrations. The model reproduced the sequential reduction reaction. O2 was reduced first after 30 hours then followed by NO3- after 31 hours. In this study, the numerical simulation of NO3- was done using the multicomponent solute transport model to determine the effect of pore velocity and input C H2O concentration needed to reduce the NO3- leaching. It is revealed that the multicomponent solute transport model is useful to design the land, treatment system for NO3- removal from wastewater..
124. Gingging Guerra, Kenji Jinno, Yoshinari Hiroshiro, Koji Nakamura, Multi-component solute transport model with cation exchange under redox environment and its application for designing the slow infiltration setup, Memoirs of the Faculty of Engineering, Kyushu University, 64, 1, 78-100, 2004.03, The present trend of disposing treated sewage water by allowing it to infiltrate the soil brings a new dimension to environmental problems. It is therefore necessary to identify the chemicals likely to be present in treated sewage water. A soil column experiment was conducted to determine the behavior of chemical species in soil columns applied with secondary treated sewage water. To predict the behavior of chemical species, a multicomponent solute transport model that includes the biochemical redox process and cation exchange process was developed. The model computes changes in concentration over time caused by the processes of advection, dispersion, biochemical reactions and cation exchange reactions. The solute transport model was able to predict the behavior of different chemical species in the soil column applied with secondary treated sewage water. The model reproduced the sequential reduction reaction. To design the safe depth of plow layer where NO 3 - is totally reduced, a numerical study of NO 3 - leach was done and it was found out that the pore velocity and concentration of CH 2O at the inject water was found to affect NO 3 - reduction in the mobile pore water phase. It is revealed that the multicomponent solute transport model is useful to design the land treatment system for NO 3 removal from wastewater..
125. Moshood N. Tijani, Kennji Jinno, Yoshinari Hiroshiro, Environmental impact of heavy metals distribution in water and sediments of Ogunpa River, Ibadan area, southwestern Nigeria, Journal of Mining and Geology, 10.4314/jmg.v40i1.18811, 40, 1, 73-83, 2004.01, [URL], Geochemical evaluation of distribution of heavy metals in water and sediments of Ogunpa River within Ibadan metropolis in Southwestern Nigeria is presented in respect of anthropogenic contamination from the surrounding urbanized catchment area. The results revealed low contamination or enrichment of the heavy metals (Pb, Zn, Cu, Cd, and As) in the water phase. Also, the sediment phase (<63μm) of the drainage system is anthropogenically enriched in Ph, Zn, Cu, Cd, As and t-Hg with all recording an estimated anthropogenic factor (AF) value above 1. The estimated index of geoaccumulation (Igco) with a value of approximately 2 for Pb, Zn and t-Hg indicates moderate or middle level contamination in the sediments while Igco of <1 recorded for Cu, Cd, and As indicate very low or no contamination. This trend is however, reversed in the water column with Cu and Cd having Igco value of 1.2 and 3.2 respectively, pointing to relative partitioning of the metals between the two media. Quantification of degree of pollution revealed high anthropogenic contribution for Pb (75%), Zn (75%) and t-Hg (60%), indicating enrichment by a factor of at least 5 in the sediment phase, while anthropogenic in-put also accounts for 70% (Cu) and 90% (Cd) in the water column. Furthermore, correlation of electrical conductivity (EC) peaks with the high values of Pb, Zn and t-Hg indicated that the inputs are related to anthropogenic sources along the stretches of the Ogunpa channel. The sources of contamination are attributed to urbanised anthropogenic sources, mostly vehicular emissions and related repair products, domestic sewage and effluents, varied household garbages and refuse dumps including incineration bye-products. Based on the overall evaluation, recommendations in respect of sanitization and contamination control/monitoring strategies in the study area are also presented..
126. Gingging Guerra, Kenji Jinno, Yoshinari Hiroshiro, Variation of chemical species in infiltrating treated sewage water using the multi-component solute transport model, IAHS-AISH Publication, 285, 92-99, 2003.12, Due to uncertainties raised about the presence of contaminants from recycled water it is necessary to identify the chemicals likely to be present in treated sewage water, and assess approaches for minimizing their release. The relevant physical, chemical and biochemical processes must be understood in order to determine the state and movement of contaminants. To simulate the mechanisms responsible for the movement of chemical species, predictive tools in the form of mathematical models have been developed. This study deals with the processes and chemical transport in an aqueous soil similar to paddy fields where successive reduction reactions occur. To examine the behaviour of the different chemical species present in the secondary treated sewage water, a two-soil column experiment was conducted. In order to more fully understand chemical and biochemical processes, a solute transport model that takes into consideration the biochemical reactions and cation exchange reactions was developed in this study. The soil column experiment and the solute transport model produced interesting observations on the behaviour of different chemical species. The observed concentrations correlated fairly well with the simulated concentrations and the sequence of reduction reactions were reproduced by the developed solute transport model..
127. 広城吉成,神野健二,籾井和朗,斎藤啓一, 肥料に含まれる主要陽イオンによる地下水水質への影響, 水工学論文集第42巻,pp.379〜384,1998年2月., 1998.02.
128. Yoshinari HIROSHIRO, Motohiro KUBOTA, Kenji JINNO, Takushi YOKOYAMA, and Shin-Ichiro WADA, Properties of multicomponent transport with redox processes in a subsurface environment, International Symposium on Lowland Technology(ISLT’98),pp.487〜494,Nov.1998., 1998.11.
129. Yoshinari HIROSHIRO, Kenji JINNO, Takushi YOKOYAMA, and Shin-Ichiro WADA, Behavior of chemical species under reducing condition in a subaqueous soils column, Lowland Technology International ,Vol.1, No.1, pp.59〜66, June.1999., 1999.06.
130. 広城吉成,神野健二,和田信一郎,徳永隆司,森田 守, 酸化還元状況下における主要陽イオンの動態, 水環境学会誌,第22巻,第12号,pp.1005〜1009,1999年12月., 1999.12.
131. Y. Hiroshiro, K. Jinno, S. I. Wada, T. Yokoyama, M. Kubota, Multicomponent solute transport model with cation exchange in a redox subsurface environment, ModelCARE'99 Conference
IAHS-AISH Publication
, 265, 474-480, 2000.01, In order to clarify the behaviour of chemical species under reducing condition in a subaqueous soil similar to a paddy field, a column experiment was carried out. As Mn- and Fe-(hydr)oxides were dissolved by microbially mediated reduction, Na+, K+, Mg2+, Ca2+, Mn2+, and Fe2+ existed in the pore water as major cations. The Ca2+ concentration had a tendency to decrease in the layer at 5-25 cm depth in the column, whereas the Ca2+ concentration increased with time below 45 cm depth. This phenomenon can be assumed to be due to the desorption of Ca2+, by Mn2+ and Fe2+, and its infiltration. Therefore, it is necessary to develop a solute transport model which takes into account both biochemical and cation exchange reactions. In this paper, a simulation model that considers both reactions is described and applied to simulate the results of the column experiment. The reliability of this model was evaluated by comparing the calculated results with the result of the experiment..
132. Yoshinari Hiroshiro, Kazuro Momii, Kenji Jinno, Takushi Yokoyama, Hydrochemical solute transport model in subsurface environment
Model development and laboratory tests, IAHS-AISH Publication, 237, 321-331, 1996.12, This paper presents a numerical model for predicting solute transport with multicomponent chemical reactions in subsurface. A nonlinear least-squares estimation by the Levenberg-Marquardt method is adopted for obtaining numerical solution of the chemical reaction term in the advection-dispersion equations. To test the reliability of the model, a laboratory experiment is performed with continuous injection of KCl solution into an undisturbed soil column. The values of cation exchange capacity of the soil used in the experiment have spatial distribution with a range from 15 meq/100g in the upper part of the column to 5 meq/100g in the lower part. Based on the numerical and experimental results, the effect of the choice of selectivity coefficient on the cation concentrations is investigated. When the exponential function with respect to the equivalent fraction of K+ on sorption site is employed for selectivity coefficient between Ca2+ and K+, the calculated results by the model developed here are in good agreement with the measured vertical distributions of the cation concentrations in solution and sorption sites. The use of fixed selectivity coefficient results in poor prediction accuracy. It is concluded that the accuracy of model predictions can be improved by suitable choice of selectivity coefficient for the soil being considered..
133. Y. Hiroshiro, K. Jinno, S. I. Wada, T. Yokoyama, M. Kubota, Multicomponent solute transport model with cation exchange in a redox subsurface environment, ModelCARE'99 Conference
IAHS-AISH Publication
, 265, 474-480, 2000.01, In order to clarify the behaviour of chemical species under reducing condition in a subaqueous soil similar to a paddy field, a column experiment was carried out. As Mn- and Fe-(hydr)oxides were dissolved by microbially mediated reduction, Na+, K+, Mg2+, Ca2+, Mn2+, and Fe2+ existed in the pore water as major cations. The Ca2+ concentration had a tendency to decrease in the layer at 5-25 cm depth in the column, whereas the Ca2+ concentration increased with time below 45 cm depth. This phenomenon can be assumed to be due to the desorption of Ca2+, by Mn2+ and Fe2+, and its infiltration. Therefore, it is necessary to develop a solute transport model which takes into account both biochemical and cation exchange reactions. In this paper, a simulation model that considers both reactions is described and applied to simulate the results of the column experiment. The reliability of this model was evaluated by comparing the calculated results with the result of the experiment..
134. Kazuro Momii, Yoshinari Hiroshiro, Kenji Jinno, Ronny Berndtsson, Reactive solute transport with a variable selectivity coefficient in an undisturbed soil column, Soil Science Society of America Journal, 10.2136/sssaj1997.03615995006100060001x, 61, 6, 1539-1546, 1997.01, [URL], The spatial distribution of major ion concentration limits the predictability of solute sport processes in field soils. Therefore, it is important to analyze solute transport with chemical reactions based on results obtained from field soils and numerical simulation. A simulation model with cation-exchange reactions was developed and applied to solute-transport analysis of an undisturbed field soil. Chemical reaction terms in the convective-dispersive equation were estimated by the Levenberg-Marquardt nonlinear least-squares regression technique to satisfy physical stud chemical processes simultaneously. The reliability of the model was tested with liquid-phase and solid-phase concentrations of measured spatial distributions of Ca2+, Mg2+, Na+, and K+ after continuous infiltration of KCl solution into an undisturbed soft column. The experimental results revealed that the selectivity coefficients for Ca-Na and Co-Mg exchange could be kept constant, while those for Ca-K exchange increased with the equivalent fraction of K+ in the solid phase. The effects of the exchange selectivity coefficient on reactive solute transport are discussed based on the simulation results. When a constant selectivity coefficient was used, the model failed to predict the spatial distributions of cation concentrations in the solid phase. Thus, model predictions can be improved by use of variable instead of constant selectivity coefficients..
135. Yoshinari Hiroshiro, Kazuro Momii, Kenji Jinno, Takushi Yokoyama, Hydrochemical solute transport model in subsurface environment
Model development and laboratory tests, IAHS-AISH Publication, 237, 321-331, 1996.12, This paper presents a numerical model for predicting solute transport with multicomponent chemical reactions in subsurface. A nonlinear least-squares estimation by the Levenberg-Marquardt method is adopted for obtaining numerical solution of the chemical reaction term in the advection-dispersion equations. To test the reliability of the model, a laboratory experiment is performed with continuous injection of KCl solution into an undisturbed soil column. The values of cation exchange capacity of the soil used in the experiment have spatial distribution with a range from 15 meq/100g in the upper part of the column to 5 meq/100g in the lower part. Based on the numerical and experimental results, the effect of the choice of selectivity coefficient on the cation concentrations is investigated. When the exponential function with respect to the equivalent fraction of K+ on sorption site is employed for selectivity coefficient between Ca2+ and K+, the calculated results by the model developed here are in good agreement with the measured vertical distributions of the cation concentrations in solution and sorption sites. The use of fixed selectivity coefficient results in poor prediction accuracy. It is concluded that the accuracy of model predictions can be improved by suitable choice of selectivity coefficient for the soil being considered..

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