Kyushu University Academic Staff Educational and Research Activities Database
List of Papers
Kazuaki Hiramatsu Last modified date:2021.10.07

Professor / Division of Bioproduction Environmental Sciences / Department of Agro-environmental Sciences / Faculty of Agriculture


Papers
1. Ta Dang Thuan, Bui Quoc Lap, Le Minh Thanh, Masayoshi Harada, Kazuaki Hiramatsu and Toshinori Tabata, Ta Dang Thuan, Bui Quoc Lap, Le Minh Thanh, Masayoshi Harada, Kazuaki Hiramatsu and Toshinori Tabata, Journal of the Faculty of Agriculture, Kyushu University, https://doi.org/10.5109/4363557, 66, 1, 97-104, 2021.02, Many lakes in inner Hanoi have been affected by eutrophication, which commonly leads to uncontrolled growth of algae, generation of cyanobacteria and toxic algae, increased water–treatment costs, and lake shallowing. This study presents an overview of the recent eutrophication status in Hanoi lakes and compares the lakes with Cu Chinh Lake based on a case study performed from April 2017 to March 2018. The eutrophication was mainly assessed by comparing the nutritional parameters (phosphorus and nitrogen) with values of poor nutrition and the concentration of algal biomass with concentrations found in hypereutrophic lakes. In addition, we investigated which nutrients contribute to limiting the growth of algae based on the total nitrogen/total phosphorus ratio, and we identified groups of algae that contained typical species in Cu Chinh Lake. The nutrient levels and algal biomass in many lakes were maintained between the eutrophic and hypereutrophic limits and underwent seasonal changes throughout the year. In Cu Chinh Lake, phosphorus is the predominant limiting nutrient for the development of algae. Thus, some typical algae genera, such as Microcystis, Anabaena of cyanobacteria, and Scenedesmus of green algae, are biological indicators of eutrophication in the lake..
2. Sai Hong Anh, Toshinori Tabata, Kazuaki Hiramatsu, Le Viet Son and Masayoshi Harada, Floodwater impacts on residential areas in floodplain areas along Day River system in emergency situation, Journal of the Faculty of Agriculture, Kyushu University, https://doi.org/10.5109/4363555, 66, 1, 77-90, 2021.02, Hanoi, the capital of Vietnam, is protected from floods by dike systems for the Red and Day Rivers. In emergency situations resulting from catastrophic floods, floodwater from the Red River is discharged into the Van Coc Lake, which is a regulating reservoir that drains into the Day River system through the Day Weir at the downstream end of the Van Coc Lake. The authors investigated the flood mitigation function of the Van Coc Lake and identified an optimal operation scenario for the lake for the largest recorded flood, which occurred between the 16th and 27th of August 1971. However, a comprehensive evaluation of the flood risk level in residential areas within the floodplain areas located along the Day River system to determine an optimal operation scenario has not been conducted. In this study, a two–dimensional depth-integrated hydrodynamic model was employed to investigate flood risk levels in these residential areas when the floodwater level reached 11.0 m, 12.0 m, and 12.72 m (the flood peak) at the Day Weir and at 10 and 30 h after the flood peak, under the optimal operation scenario. The time at which floodwater from the Van Coc Lake reached the Day Weir was referred to as Time–0 in this study and was used to estimate the movement of floodwater. The study area, from the Day Weir to the downstream end, was more than 100 km in length and was divided into three zones: the northern part, designated Zone 1; the central part, designated Zone 2; and the downstream end part, designated Zone 3. The simulation results were used to produce reliable flood susceptibility maps that identify the areas at greatest risk of being impacted by floodwater. At the flood peak time, residential areas in the study area were inundated at levels of 84.00% (9.50 km2) in Zone 1, 71.84% (29.18 km2) in Zone 2, and 98.59% (13.31 km2) in Zone 3. Floodwater needed 75, 87, and 135 h from Time–0 to reach 11.0 m, 12.0 m, and the flood peak at 12.72 m at the Day Weir. The results of this study form a basis for future land planning and the design of risk reduction strategies for the Day River system and serve as a strong warning about the dangers of floodwater throughout the study area..
3. Sai Hong Anh, Toshinori Tabata, Kazuaki Hiramatsu, Masayoshi Harada and Luong Ngoc Chung, An optimal scenario for the emergency solution to protect Hanoi Capital from the Red Riverfloodwater using Van Coc Lake, Journal of Flood Risk Management, https://doi.org/10.1111/jfr3.12661, 13, 4, 2020.12, The Red River dike system was built, and an emergency solution was implemented to protect Hanoi Capital city from flood disasters. In the solution, floodwater from the Red River is discharged through the Van Coc Gate, with an overflow point into Van Coc Lake, and is drained downstream through the Day Weir. However, an optimal scenario for the operating procedure of the emergency solution, based on a comprehensive evaluation of the flood risk level from the Red River to the residential areas located outside the protected areas of the dike system, has not been adequately addressed to date. In this study, we employed the latest digital elevation map in a high spatial resolution for the first time, and a two-dimensional depth-integrated hydrodynamic model was utilised to obtain the optimal operation for the emergency solution. The optimal scenario was determined to minimise the flood risk level to the residential areas and optimise the inflow discharge at the Van Coc Gate and the overflow point, and the outflow discharge at the Day Weir for ensuring the safety of the operating system. This study lays a promising foundation for designing risk-reduction strategies in Hanoi Capital..
4. Trieu Anh Ngoc, Vu Thi Hoai Thu, Kazuaki Hiramatsu, Vu Le Duy Thai, Do Van Dao, Vu Hai Son, Pham Tran Hoang Son, Assessing Water Quality in the Cai River, Ninh Thuan Province, Vietnam, by Field Observations, Journal of the Faculty of Agriculture, Kyushu University, https://doi.org/10.5109/4103897, 65, 2, 321-330, 2020.09, The Cai River is the main river in Ninh Thuan Province, Vietnam, and plays a crucial role as arterial river in the entire province. The Cai River is the main river of the Cai River basin; the Sat, Cho Mo, and Ngang Rivers are located on the left hand side, whereas the Ong, Cha, Than, Quao, and Lu Rivers are located on the right hand side of the basin. In this study, the prevailing water quality of the Cai River basin was evaluated by comparing the observed water quality in the Cai River and at the confluences of its tributaries, and the evaluated water quality of the Cai River was compared with the Vietnamese standards. Several parameters, including the pH, total suspended solids, phosphate, dissolved oxygen, biochemical oxygen demand, and chemical oxygen demand were selected for evaluation. Results show that in comparison with water quality standards of Vietnam for irrigation or other domains with low water quality, the water quality standards in the Cai River and in confluences of its tributaries were not significantly affected by polluting factors..
5. Makoto Fukui, Kazuaki Hiramatsu, Shinji Fukuda, Dario Pineda, Masayoshi Harada and Toshinori Tabata, Evaluation of Water-Saving Methodologies for Rice Farming Using a Distributed Long-Term Rainfall-Runoff Model Incorporated Agricultural Ponds Detected by Multi-Temporal SAR Images in the Ibague Watershed, Colombia, Journal of the Faculty of Agriculture, Kyushu University, https://doi.org/10.5109/4103896, 65, 2, 313-320, 2020.09, A distributed long–term rainfall–runoff model was developed to quantify the watershed scale impacts of water–saving measures in the Ibague watershed, Colombia. The water–saving effects were evaluated by scenario analyses that incorporated the introduction of a water–saving irrigation method (early stopping) to improve irrigation efficiency with respect to redundant paddy irrigation water. In addition to water stopping, the impacts of a new water–saving rice genotype are analyzed. To calculate rainfall–runoff, the Sugawara tank model was utilized. The tank model quantified runoff discharges from forest, upland, paddy field, and urban areas by incorporating each land type into every mesh for a distributed rainfall–runoff model. This quantified the rainfall–runoff characteristics for each land use. Agricultural ponds and irrigation canals were allocated to each corresponding mesh to model irrigation management practices in the watershed. Agricultural ponds, which have a significant effect on the water balance at the watershed scale, were detected by performing cluster analysis on the seasonal transition of the backscatter coefficient obtained from multi–temporal Sentinel–1 SAR images. Quantitative analyses of the impacts of water–conservation under various scenarios indicated that the early–stopping irrigation method reduced water consumption by 9.4%, compared to the conventional methods. The scenarios, which assumed the introduction of a new water–saving rice genotype, assumed regular irrigation intervals of one or two days and indicated 24.1% and 48.2% reductions, for water consumption, respectively, compared to conventional irrigation methods. Scenarios that implemented a new water–saving rice genotype, as well as the early–stopping irrigation method showed reductions of 30.7% and 53.2% in water consumption compared to the conventional irrigation method, for the one and two day irrigation periods respectively..
6. Sai Hong Anh, Toshinori Tabata, Kazuaki Hiramatsu, Masayoshi Harada and Le Viet Son, Flood Hazard Assessment of Residential Areas Inside the Van Coc Lake, Hanoi, in an Emergency Situation, Journal of the Faculty of Agriculture, Kyushu University, https://doi.org/10.5109/4103895, 65, 2, 305-311, 2020.09, The Van Coc Lake is a regulating reservoir located in the Dan Phuong and Phuc Tho Districts (30 km from the center of the Hanoi Capital). It is usually dry and includes arable land and residential areas. To protect the Hanoi Capital from flood disasters in emergency situations, floodwater is received from the Red River through the Van Coc Gate and the overflow point, and the floodwater drains downstream through the Day Weir. The authors have proposed the effective operating procedure in the emergency situations by optimizing the inflow discharge at the Van Coc Gate and the overflow point, and the outflow discharge at the Day Weir for ensuring the flood mitigation effect of the lake and the safety of the operating system. However, risk–reduction strategies based on a flood hazard assessment for the residential areas located inside the lake have not been adequately resolved. In this study, the inundation situations inside the lake area were identified with a two–dimensional depth–integrated hydrodynamic model in high resolution. The results indicated that the residential areas were highly vulnerable to floods. When the water depth in front of the Day Weir reached 1.0 m, 3.0 m, and its peak at 4.9 m, 57.13%, 85.52%, and 99.76% of the total residential areas (6.33 km2) were inundated respectively. The highest velocity was primarily focused around the Van Coc Gate, overflow point, and Day Weir with velocities of 0.6 – 2.0 m/s..
7. Asari Takada, Kazuaki Hiramatsu, Trieu Anh Ngoc, Masayoshi Harada and Toshinori Tabata: Development of a Distributed Rainfall-runoff Model Incorporated with Tank Models for Several Land Utilizations and Quantitative Evaluation of Runoff Change Induced by Rural Development and Climate Change, Transactions of the Japanese Society of Irrigation, Drainage and Rural Engineering, 88(1), pp. II_11-II_20, 2020.
8. Akihiro Fukuda, Toshinori Tabata, Kazuaki Hiramatsu and Masayoshi Harada, Salinity Analysis for Tracking the Behavior of Large Freshwater Discharge into Hakata Bay Due to Heavy Rainfall Using a Three-Dimensional Sigam-Coordinate Model, Proceedings of the International Workshop on “Integrated Land & Water Management and Climate Change in Vietnam and Japan” between Vietnam National University of Agriculture and Kyushu University, 86-93, ISBN 978-604-924-439-1, 2019.11, Massive freshwater discharges due to heavy rainfall have recently caused negative changes such as red tides and anoxic water masses in semi-enclosed bays. Hakata Bay, one of the semi-enclosed bays of Fukuoka, Japan, has experienced red tides and anoxic water masses due to large freshwater inflows after extreme rainfall events. In this research, the impacts of large freshwater discharges were evaluated by analyzing the horizontal and vertical salinity distribution using a three-dimensional  -coordinate model. Specifically, the bay was examined after the heavy rainfall event that greatly damaged Fukuoka City on 16 September 2002. The calculation period was 11–27 September 2002. River discharge values were calculated using Sugawara’s tank models, which were considered to be the river inflow in a hydrodynamic and salinity diffusion model of Hakata Bay. The model was validated, and the results showed high reproducibility; the calculated tidal current and salinity values agreed well with the observed data. The results also showed that: (1) salinities less than 15.0 psu were found at the river mouths just after the heavy rainfall; (2) low-salinity water spread across the surface of the inner part of the bay; and (3) salinity differences between the surface and bottom were large (approximately 4 psu) and lasted for three days after the heavy rainfall. These results indicate that red tides and anoxic water masses could be induced in the inner part of the bay..
9. Asari Takada, Kazuaki Hiramatsu, Ngoc Anh Trieu, Masayoshi Harada and Toshinori Tabata, Development of a Distributed Rainfall-Runoff Model Incorporated with Tank Models of Several Land Uses and Evaluation of Impact of Climate Change on Rainfall-Runoff in a Vietnamese Watershed, Proceedings of the International Workshop on “Integrated Land & Water Management and Climate Change in Vietnam and Japan” between Vietnam National University of Agriculture and Kyushu University, 94-100, ISBN 978-604-924-439-1, 2019.11, In this study, a distributed rainfall-runoff model, which could overcome the problems of calculation time and data scarcity in Southeast Asian watersheds was developed to quantitatively analyze the changes in runoff due to rainfall variations under future climate change scenarios. To capture a variety of land uses and the spatial non-uniform rainfall characteristics of the tropical region, a distributed rainfall-runoff model, which represents the watershed as a square mesh aggregate, was constructed. To greatly reduce the calculation time, the original digital elevation map data with a 90 m mesh were scaled to a resolution of 4500 m. Four Sugawara’s tank models representing the rainfall-runoff characteristics of paddy, upland field, urban, and forest areas were incorporated into each mesh element to simulate the runoff from different land uses. A watershed groundwater tank model covering the entire watershed was incorporated to represent the temporally stable base-flow component. The scenario analyses related to future rainfall change indicated that the annual runoff and peak discharge from the watershed increased with the change rates of the future rainfall. The annual runoff discharge had almost the same trend as the rainfall change rates, and the peak discharge was higher than the increase rates of rainfall during the period..
10. Sai Hong Anh, Toshinori Tabata, Kazuaki Hiramatsu and Masayoshi Harada, Evaluation of Flood Mitigation Function of the Van Coc Lake in a Catastrophic Flood Event of the Red River, Northern Vietnam, Proceedings of the International Workshop on “Integrated Land & Water Management and Climate Change in Vietnam and Japan” between Vietnam National University of Agriculture and Kyushu University, 101-108, ISBN 978-604-924-439-1, 2019.11, The Van Coc Lake is a regulating reservoir located in the Dan Phuong and Phuc Tho Districts (30km from the center of Hanoi Capital). In emergency situations, floodwater from the Red River is discharged through the Van Coc Gate and the overflow point on the bank to the downstream through Day Weir. However, the flood mitigation function of the Van Coc Lake in emergency situations to minimize flood risk levels to residential areas located outside protected areas of the Red River dike system (the river area inside the dike system) has not been adequately addressed. In this study, a two-dimensional depth-averaged hydrodynamic model and the latest digital elevation map were utilized to evaluate the flood mitigation function of the Van Coc Lake in the emergency situation. The results of our analyses showed that the lake was a useful regulating reservoir to protect the Hanoi Capital in flood disaster events. However, the residential areas were inundated with 96.0 % (38.0 km2) of the total residential areas vulnerable to flood disasters. This study is aimed at being a foundation for further research on designing flood risk-reduction strategies in Hanoi Capital..
11. Toshinori Tabata, Akihiro Fukuda, Kazuaki Hiramatsu and Masayoshi Harada, Applicability of a Three-Dimensional Dissolved Oxygen Model, Proceedings of the International Workshop on “Integrated Land & Water Management and Climate Change in Vietnam and Japan” between Vietnam National University of Agriculture and Kyushu University, 109-116, ISBN 978-604-924-439-1, 2019.11, Because of the eutrophication accompanying the high economic growth in the 1960s, the occurrence of anoxic water masses in semi-enclosed bays in Japan has been a serious problem, and its dynamic analysis is an urgent issue. The ecosystem model is currently the most widely used model for analyzing the dynamics of anoxic water masses. The ecosystem model can model material circulation in a target area in detail and can analyze the influential factors precisely. However, as the number of required state variables increases, the number of parameters to be determined also increases. Therefore, the ecosystem model requires not only time-intensive calculations but also a considerable period to build the model. Therefore, in this study, a three-dimensional dissolved oxygen (DO) model was constructed for the Ariake Sea, for which a dynamic analysis of anoxic water masses is required. The DO model adds a net oxygen consumption term to the turbulent DO diffusion equation and is much simpler than an ecosystem model. As a result, it was possible to reproduce the anoxic water mass generated in 2010 in the Ariake Sea. Although the reproduction of the short-term fluctuations of the DO is a future task, the DO model developed in this study is an effective method for analyzing the dynamics of the anoxic water mass in the Ariake Sea..
12. Makoto Fukui, Kazuaki Hiramatsu, Shinji Fukuda, Dario Pineda, Toshinori Tabata and Masayoshi Harada, Development of long-term rainfall-runoff model and scenario analyses for water-saving effect in rice farming in the Ibague Watershed, Colombia, Proceedings of the International Workshop on “Integrated Land & Water Management and Climate Change in Vietnam and Japan” between Vietnam National University of Agriculture and Kyushu University, 117-123, ISBN 978-604-924-439-1, 2019.11, A distributed long-term rainfall-runoff model was developed and various scenarios analyzed to quantify water-saving effect at the watershed scale. This study focused two points: a water-saving irrigation method called early stopping to improve irrigation efficiency with respect to redundant paddy irrigation water, and the introduction of a new water-saving rice genotype in the Ibague Watershed, Colombia. The Sugawara’s tank model, which is used for calculating runoff discharge from forests, upland and paddy fields, and urban areas, was incorporated into each mesh of a distributed rainfall-runoff model to overcome the scarcity of hydro-meteorological data. A hypothetical pond was placed in each mesh that included a paddy field to reproduce actual irrigation management practices in the watershed. Quantitative analyses of the various scenarios to evaluate the effect of water-saving paddy irrigation showed that using the early stopping irrigation method reduced the water consumption by 9.9 % compared to the conventional irrigation method. The scenarios, which prolonged one- and two-day irrigation intervals by assuming the use of a new water-saving rice genotype and the early stopping irrigation method, showed 33.3 % and 51.6 % reductions in water consumption, respectively, compared to the conventional irrigation method..
13. Misaki Kawara, Masayoshi Harada, Kazuaki Hiramatsu and Toshinori Tabata, Experimental Suppression of Phytoplankton Growth Employing Bactericidal Effects of Copper Ions under Eutrophic Conditions, Proceedings of the International Workshop on “Integrated Land & Water Management and Climate Change in Vietnam and Japan” between Vietnam National University of Agriculture and Kyushu University, 185-188, ISBN 978-604-924-439-1, 2019.11, Eutrophication of closed bodies of freshwater such as lakes and reservoirs has increased in recent times, leading to deterioration of aquatic environments due to hypertrophication and occurrence of cyanobacteria blooms over the entire water surface during summer. This study quantitatively assessed methods to control algal growth using the bactericidal properties of copper ions (Cu2+) as a specific anti-eutrophication measure for aquatic environment restoration in a hypertrophic waterbody. In particular, this study examined the feasibility and effectiveness of controlling phytoplankton growth using bactericidal effects of copper ions under standardized laboratory conditions. Our results indicated that inhibitory effects of Cu2+strongly depend on phytoplankton abundance and nutrient concentrations. Furthermore, Cu2+ concentrations of about 400 μg/L successfully suppressed Ch1.a production by all algae including cyanobacteria to 10 µg/L or less, which may help prevent algal blooms..
14. Takuma Kobayashi, Masayoshi Harada, Kazuaki Hiramatsu and Toshinori Tabata, Seasonal Changes in Phytoplankton characteristics in a Hyper-eutrophic Water Area under Nitrogen Limitation, Proceedings of the International Workshop on “Integrated Land & Water Management and Climate Change in Vietnam and Japan” between Vietnam National University of Agriculture and Kyushu University, 189-194, ISBN 978-604-924-439-1, 2019.11, In recent years, eutrophication has increased, leading to deterioration of the aquatic environment due to hypertrophication causing the appearance of water blooms over a long period of time over the entire water surface. This study was aimed to elucidate the mechanisms of how abnormal proliferation of phytoplankton occurs in a hypertrophic agricultural reservoir. As an example of such reservoir, we considered a pond extremely high in PO₄-P and highly nitrogen limited (Pond A) and conducted quantitative analysis on the dynamic characteristics of the water quality through detailed aquatic environmental survey. Furthermore, the characteristics of seasonal changes in phytoplankton within hypertrophic waters were investigated by analyzing the data on the water quality obtained for an agricultural reservoir (Pond B located near the Pond A) as an eutrophicated waterbody. The seasonal variations in Chl.a in Pond A were characterized by the dominance of cyanobacteria and an increase in NO₃-N due to the high water inflow load during the rainy season. However, the different situation was observed for Pond B. Specifically, cyanobacterial Chl.a exceeded 150 µg/L during the period from August to October in 2018, and this was caused by the nitrogen inflow due to the heavy rainfall in early July. As a result of the phytoplankton growth, despite having the shallow water depth of approximately 2 m, the water near the bottom became strongly reductive having Oxidation-Reduction Potential (ORP) < -150 mV due to anoxia. It was implied that the occurrence of such a strong reductive state led to diminution of PO₄-P and NH₄-N, and consequently, to the generation of H₂S, indicating the severity of aquatic environmental problems in the studied hypertrophic shallow waterbody..
15. Vu Thi Hoai THU, TABATA Toshinori, HIRAMATSU Kazuaki, NGOC Anh Trieu, HARADA Masayoshi, Evaluation of Influence of River Inflow Discharge and Tidal Level to Spatial-temporal Distribution of Salinity in Can Gio Area, South of Vietnam by Two Series of Field Observations, Journal of the Faculty of Agriculture, Kyushu University, 64, 2, 345-353, 2019.09, This study assesses the influences of river inflow discharge and tidal levels on the spatial–temporal distribution of salinity along the main rivers in Can Gio mangrove forest in the south of Vietnam. Field observations were conducted to collect salinity time series, spatial salinity distribution, and vertical profiles of salinity during two periods in the 2017 and 2018 wet seasons. Period I (2018) experienced a high discharge from upstream rivers as well as at middle tide, while Period II (2017) had a regular discharge from the upstream rivers and at spring tide. The results showed that salinities in Can Gio area changed depending not only on the tidal regime from the East Sea, but also on river discharge resulting from rainfall runoff. Most of the freshwater flows into Can Gio area through Phu Xuan, which is located at the upstream end of the observed area. The salinities at Phu Xuan changed significantly in Period II, with the practical salinity unit (psu) ranging from 1.6 to 6.0, while in Period I salinity only ranged from 0.1 to 0.4 psu. The salinities along the main rivers in the area, Long Tau River and Soai Rap River, changed depending on their respective distances to the sea, i.e. sites closer to the sea had a higher salinity. Conspicuously, the salinities along Thi Vai River were very high, approximately 20psu, even though the distances to the sea were relatively large. This unusual salinity prevalence can be explained by the location and surrounding topography of Thi Vai River, as its upstream inflow is relatively small. Furthermore, this narrow inlet is combined with peculiar topography and a river intersection, causing an unmixing water area..
16. Sai Hong Anh, Toshinori Tabata, Kazuaki Hiramatsu, Masayoshi Harada and Le Viet Son, Assessment of floodwater behavior in Van Coc Lake, Hanoi in case of emergency situation, Japan Agricultural Research Quarterly, 53, 3, 181-190, 2019.07, Van Coc Lake located in the Dan Phuong and Phuc Tho districts of Hanoi, Vietnam has an area of 30.83 km2. It is usually dry and utilized as arable land and residential areas. However, in order to protect the city of Hanoi from catastrophic floods, in emergency situations Van Coc Lake receives the floodwater from the Red River as a regulating reservoir and drains the floodwater to the downstream Day River through the Day weir. In this study, we performed numerical simulations to assess the behavior of floodwater in Van Coc Lake and evaluated the impact of floodwater on the residential areas of Van Coc Lake. A two-dimensional depth-integrated hydrodynamic model was constructed to simulate inundation in Van Coc Lake in the case of the different inflow rates from the Van Coc [sluice] Gate that is located on the banks of the Red River. The model was firstly validated with observations from the Red River and the effects of Manning’s coefficient of roughness on the floodwater behavior were also examined. In case of emergency situations, Van Coc Lake has to receive an inflow of 2,500 m3/s into the area. Inflow rates of 1,200 m3/s and 600 m3/s were also examined to compare the results. The simulation results indicate that Van Coc Lake was entirely inundated in 13, 28, and 56 hours by inflow rates of 2,500, 1,200, and 600 m3/s, respectively. Between 66% and 99% of residential areas were inundated. The highest-velocity areas primarily focused behind the gate with a velocity of 1.5–1.8 m/s. The spatially variable Manning’s coefficient of roughness n was effective for predicting local flow velocities and the spread of inundated areas. .
17. Vu Thi Hoai Thu, Toshinori Tabata, Kazuaki Hiramatsu, Trieu Anh Ngoc and Masayoshi Harada, Impact of gate operating modes of sea dikes on hydrodynamic regime and inundated area in Can Gio Bay, Coastal Engineering Journal, https://doi.org/10.1080/21664250.2019.1579460, 61, 2, 171-186, 2019.05, [URL], Ho Chi Minh City gets severely inundated by upstream flooding and a combination of rising spring tides and rain, owing to the combined impacts of rapid urbanization and sea level changes. A sea dike to close Can Gio Bay has been proposed to regulate storage and control water levels in the drainage and sewer system of Ho Chi Minh City. However, this proposed sea dike and different gate operating modes could significantly change the hydrodynamic regime in Can Gio Bay. In this study, a two-dimensional hydrodynamic model was developed to assess changes in the hydrodynamic regime after construction of the sea dike, including fluctuations in the inundated areas in Can Gio Bay mangrove forests. The results show that sea dike construction is an effective solution for controlling water levels and reducing inundation, especially considering a sea level rise scenario in the year 2050. Further, the gate operation mode also affects the effectiveness of inundation reduction, which is approximately 10% better than the same sea dike type without gate operation. However, the sea dike was less effective in a sea water level rise scenario in 2100 for all scenarios..
18. Asari Takada, Kazuaki Hiramatsu, Trieu Anh Ngoc, Masayoshi Harada and Toshinori Tabata, Development of an optimizing method for the operation rule curves of multi-purpose reservoir in Southeast Asian watershed, Paddy and Water Environment, https://doi.org/10.1007/s10333-019-00711-8, 17, 2, 195-202, 2019.04, Water scarcity and flooding constitute major problems for developing countries located within the tropical climatic region of Southeast Asia. In addition, regional water consumption is increasing and water usage patterns have been changing recently. Therefore, an advanced water resources management framework that considers both water supply and flood control is needed. Multipurpose reservoirs are widely used to manage water resources efficiently; however, water-related problems occur with reservoirs in Southeast Asian watersheds because of inadequate operation rule curves. We developed a method for constructing optimal operation rule curves for Dau Tieng Reservoir, which is one of the largest multipurpose reservoirs in Vietnam. The reservoir is used for flood control, domestic water supply, industrial uses, environmental flows, and agricultural uses, in order of priority. The operation rule curves of the Dau Tieng Reservoir comprise five reference water levels: the retarding water level, upper water level, lower water level, critical water level, and dead water level. Water release from the reservoir is determined based on the relationship between the reservoir level and the rule curves. In this study, the rule curves were newly determined using the Shuffled Complex Evolution method of the University of Arizona (SCE-UA method). The objective function for optimization was defined by focusing on the improvement of insufficient supply for agricultural uses and environmental flow downstream of the Dau Tieng Reservoir. Inadequate solutions were prevented by introducing penalty functions into the objective function. Experimental results indicate that the proposed optimization method efficiently searches for optimal rule curves..
19. Akinori Ozaki, Kazuaki Hiramatsu and Takehide Hama, Survey of Agricultural Reservoirs Damaged by Torrential Rains in Northern Kyushu on July 2017, Paddy and Water Environment, https://doi.org/10.1007/s10333-019-00716-3, 17, 2, 237-246, 2019.04, The torrential rains that hit northern Kyushu, Japan, on July 5–6, 2017, caused serious damage, especially in Asakura City, Fukuoka Prefecture, and in Hita City, Oita Prefecture. The primary meteorological mechanism that caused these torrential rains can be summarized as record-breaking heavy rains caused by linear rainbands in northern Kyushu. These heavy rains triggered hillside collapse, with the massive volume of driftwood and soil destroying downstream areas. Shortly after the immediate damage caused by the torrential rains was confirmed, the agricultural reservoirs were suspected to have exacerbated the flood damage in downstream areas. However, it is considered that the reservoirs helped mitigate flood impacts. To verify the disaster mitigation effect of the reservoirs on these torrential rains, the Japan Society of Irrigation, Drainage and Rural Engineering organized a survey team to investigate the damaged agricultural reservoirs in Asakura City. From the survey, four of 11 surveyed reservoirs were confirmed ravaged because of the massive driftwood and soil volume from the hillside area. However, the other reservoirs remained intact, and two distinctive characteristics were found to have helped prevent the flood from worsening. One was the reservoirs’ capacity to store soil; they had a large water capacity, and their strong walls kept the soil inside at their full water level. The other was spillway type and location. The reservoirs that had side-overflow spillways were able to discharge driftwood. Therefore, the water storage capacity of the reservoirs, dike strength, and spillway type and location are important factors that may help mitigate flooding..
20. Toshinori Tabata, Wataru Hayashi, Akihiro Fukuda, Kazuaki Hiramatsu , Development of Three Dimensional Dissolved Oxygen Model in the Ariake Sea, Japan, Proceedings of International Conference 2018 of the International Society of Paddy and Water Environment Engineering (PAWEES) and International Network for Water and Ecosystem in Paddy Fields (INWEPF), 689-697, 2018.11, In semi-enclosed bay in Japan, due to eutrophication accompanying high economic growth in the 1960's, the occurrence of anoxic water mass has been a serious problem and its dynamic analysis has been the urgent issue. Currently, the most widely used model for analyzing the dynamics of anoxic water mass is the ecosystem model. The ecosystem model can model the material circulation in the area in detail, and can analyze the influential factors precisely. However, as the number of required state variables increases, the number of parameters to be determined also increases. Therefore, the ecosystem model requires not only a long time calculation but also a considerable period to build the model. Therefore, in this study, a three dimensional dissolved oxygen (DO) model was constructed in the Ariake Sea where dynamic analysis of anoxic water mass is required. DO model is a model that adds a net oxygen consumption term to the turbulent diffusion equation of DO and is much more simply than an ecosystem model. In the previous studies, the DO model was applied only to a vertical one-dimensional model, and the oxygen consumption term was given as a constant. In this study, DO model was applied to a three-dimensional model and analyzed dynamics of anoxic water mass by giving seasonal change and locational change to oxygen consumption term. As a result, it was possible to reproduce the anoxic water mass generated in 2010 in the Ariake Sea. Although the reproduction of the short-term fluctuation of DO was a future task, the DO model developed in this study was an effective method for analyzing the dynamics of anoxic water mass in the Ariake Sea..
21. Asari Takada, Kazuaki Hiramatsu, Trieu Anh Ngoc, Masayoshi Harada and Toshinori Tabata, Development of an optimizing method for the operation rule curves of multi-purpose reservoir in Southeast Asian watershed, Proceedings of International Conference 2018 of the International Society of Paddy and Water Environment Engineering (PAWEES) and International Network for Water and Ecosystem in Paddy Fields (INWEPF), 519-528, 2018.11, Water scarcity in the dry season and flooding in the rainy season constitute major problems for developing countries located within the tropical climatic region of Southeast Asia. In addition, regional water consumption is increasing and water usage patterns are changing because of lifestyle changes and recent socioeconomic activities. Therefore, an advanced framework for water resource management that considers both water supply and flood control is needed urgently. Multipurpose reservoirs are used widely to manage water resources efficiently; however, water-related problems occur for reservoirs in watersheds in Southeast Asia because of inadequate operation rule curves. We developed a method for constructing optimal operation rule curves for Dau Tieng Reservoir, which is one of the largest multipurpose reservoirs in Vietnam. The reservoir is used for flood control, domestic water supply, industrial uses, regulation of environmental flows, and agricultural uses in order of priority. The operation rule curves of the Dau Tieng Reservoir comprise five reference water levels: the retarding water level, upper water level, lower water level, critical water level, and dead water level. Water release from the reservoir is determined based on the relationship between the reservoir level and the rule curves. In this study, the rule curves were newly determined using the SCE-UA global optimization method (Shuffled Complex Evolution method of the University of Arizona). The objective function for optimization was defined by focusing on the improvement of insufficient supply for agricultural uses and environmental flow downstream of the Dau Tieng Reservoir. Inadequate solutions were prevented by introducing penalty functions into the objective function. Following the optimization, it was concluded that the proposed optimization method efficiently searched for rule curves considered effective for ensuring both flood control and water supply..
22. Akinori Ozaki, Kazuaki Hiramatsu and Takehide Hama, Survey of Agricultural Reservoirs Damaged by Torrential Rains in Northern Kyushu on July 2017, Proceedings of International Conference 2018 of the International Society of Paddy and Water Environment Engineering (PAWEES) and International Network for Water and Ecosystem in Paddy Fields (INWEPF), 252-261, 2018.11, The torrential rains that hit northern Kyushu, Japan, on July 5–6, 2017, caused serious damage, especially in Asakura City, Fukuoka Prefecture, and in Hita City, Oita Prefecture. The primary meteorological mechanism that caused these torrential rains can be summarized as record-breaking heavy rains caused by linear rainbands in northern Kyushu. These heavy rains triggered hillside collapse, with the massive volume of driftwood and soil destroying downstream areas. Shortly after the immediate damage caused by the torrential rains was confirmed, the agricultural reservoirs were suspected to have exacerbated the flood damage in downstream areas. However, it is considered that the reservoirs helped mitigate flood impacts. To verify the disaster mitigation effect of the reservoirs on these torrential rains, the Japan Society of Irrigation, Drainage and Rural Engineering (JSIDRE) organized a survey team to investigate the damaged agricultural reservoirs in Asakura City. From the survey, 4 of 11 surveyed reservoirs were confirmed ravaged because of the massive driftwood and soil volume from the hillside area. However, the other reservoirs remained intact, and two distinctive characteristics were found to have helped prevent the flood from worsening. One was the reservoirs’ capacity to store soil; they had a large water capacity, and their strong walls kept the soil inside at their full water level. The other was spillway type and location. The reservoirs that had side-overflow spillways were able to discharge driftwood. Therefore, the water storage capacity of the reservoirs, dike strength, and spillway type and location are important factors that may help mitigate flooding..
23. Asari Takada, Kazuaki Hiramatsu, Trieu Anh Ngoc, Masayoshi Harada and Toshinori Tabata: Towards the proposal of optimum operation method for a multipurpose reservoir considering flood control and water supply in Southeast Asian watershed, Applied Hydrology, 31, 61-70, 2018.
24. Vu Thi Hoai Thu, Toshinori Tabata, Kazuaki Hiramatsu, Trieu Anh Ngoc, and Masayoshi Harada, Assessment of Spatial-temporal Distribution of Observed Salinity Based on Location and Water Depth in Can Gio Area, Southern Vietnam, Journal of the Faculty of Agriculture, Kyushu University, 63, 2, 379-385, 2018.09, The Can Gio mangrove forest in southern Vietnam hosts abundant ecological resources and plays an important role in protecting Ho Chi Minh City from storms in the East Sea. This area is currently facing environmental problems, including changes in water salinity that affect mangrove health, because of the complexity of the local river system. Freshwater from the Sai Gon - Dong Nai River system mixes with seawater from the East Sea, altering salinity at different locations along with the effects of the tidal regime. In this study, we surveyed the spatial-temporal distribution of salinity in the Can Gio area with referenec to location and river depth using commercial data loggers to record salinity time series at two locations and salinity depth profiles at 24 locations along the two main rivers in the area. Our results showed that salinity steadily declined upstream from the sea and was strongly affected by the tide regime. Salinity also changed based on the water depth, the hydrodynamic effects of current and river channel width..
25. Akihiro Fukuda, Toshinori Tabata, Yori Honda, Kazuaki Hiramatsu and Masayoshi Harada, Simulation of large fresh water behavior in Hakata Bay due to torrential rain using nested two-dimensional model, Proceedings of 21st Congress of International Association for Hydro-Environment Engineering and Research (IAHR), Asia Pacific Division (APD), 521-529, 2018.09, In this study, a numerical simulation consisting of a two-dimensional model of Hakata Bay, Kyushu Island, Japan, was conducted to analyze the impact of large river discharges due to torrential rain. Since Fukuoka city, one of the largest cities in Japan, surrounds Hakata Bay, the bay has a very complex environment, including an artificial island (Island City) in its eastern region and small bay (Imazu Bay) where tideland is spread with rich ecosystems in its western region. Tank models were applied to calculate the discharges of the 38 rivers that flow into Hakata Bay, and a two-way nesting technique, “edge nesting,” was developed and applied in the model to capture the influence of complex geographical features, such as the Island City area and the Imazu Bay area, which were nested with a high resolution mesh. The model accurately reproduced the observed tidal current and salinity data. To simulate the behavior of large river discharges, an historical simulation period including a torrential rain event (163.5 mm/d) was input into the model. The results showed that after the rain event, low-salinity water covered the entire inner part of Hakata Bay, and fresh water covered the entire area of the tidal flats and flowed out from the mouth of Imazu Bay. The behavior of this large mass of fresh water was remarkably different from usual discharge river flow. These results indicate that the environment in the bay can be significantly changed by torrential rain events..
26. Masayoshi Harada, Tran Tuan Thach, Kazuaki Hiramatsu and Toshinori Tabata, Biochemical characteristics of water quality dynamics near the bottom sediment under anaerobic state in the organically polluted reservoir, Proceedings of 21st Congress of International Association for Hydro-Environment Engineering and Research (IAHR), Asia Pacific Division (APD), 783-791, 2018.09, Anoxic conditions, occurring in enclosed water bodies from an overabundance of organic matter, cause further deterioration of the aquatic environment through nutrient elution and hydrogen sulfide production. The quantitates of biochemical reactions under anaerobic state, such as denitrification, iron reduction and sulfate reduction are important research topics when considering conservation and improvement of water quality environment. This study involved regular observations for two years in the reservoir, in which overabundant organic matter was prominent due to humic acid, to evaluate the water quality dynamic near the bottom during long-term anoxic periods. Based on the temporal changes of dissolved oxygen, nitrate-nitrogen, ammonia-nitrogen, phosphate-phosphorus, sulfide, total iron ions and sulfate, this study focused specifically on the influence of the redox state of the sediment surface during the early stage of thermal stratification on the anaerobic biochemical reactions. As a result, nitrate-nitrogen started to decrease to zero due to denitrification as soon as the anoxic sate occurred, and then both ammonia-nitrogen and phosphate-phosphorus increased linearly with time due to iron reduction after nitrate-nitrogen had decreased to zero. Sulfide began to increase linearly due to sulfate reduction as soon as nitrate-nitrogen disappeared. Also, the initial redox state of sediment impacted on the change characteristics of phosphate-phosphorus, ammonia-nitrogen and sulfide in the points of increasing timings, duration and rates. It was concluded that our results would provide important finding about the mechanisms of aqueous environmental deterioration due to organic pollution as well as beneficial information for the modification of water quality prediction model..
27. Toshinori Tabata, Kodai Nakashima, Kazuaki Hiramatsu and Masayoshi Harada, Investigation of the effects of human activities using multi-box ecosystem model in the Ariake Sea, Japan, Proceedings of 21st Congress of International Association for Hydro-Environment Engineering and Research (IAHR), Asia Pacific Division (APD), 531-538, 2018.09, In this research, the effect of human activities has been investigated in the Ariake Sea located in Kyushu Island, Japan. The Ariake Sea has been suffering from environmental degradation for more than a decade with unstable fisheries productivity. Therefore, it is important to understand the change of environmental characteristics in the Ariake Sea quantitatively. Moreover, it is concerned that the fertilizer applied for the aquaculture is effecting to the ecosystem in the sea. Also, since nutrient loading from rivers are so high that red tide or anoxic water mass occurs every year, it is significant to evaluate the effect of nutrient load to the sea. Therefore, in order to characterize the coastal environment and investigate the effect of human activities, Muti-Box Ecosystem model have constructed to simulate the water quality items in the Ariake Sea. The sea was divided into 12 boxes. Each box is comprised of three layers which is water, oxidative bottom and reductive bottom layer. Simulation period was set from 1st January 2000 to 31st December 2012. The model reproduced the water quality items well. Then, the model calculated with two different scenarios about the fertilizer application to the aquaculture and nutrient load from the river. The result showed that the fertilizer for the aquaculture has no effect to the coastal ecosystem and coastal environment would improve if the nutrient load reduced by half..
28. Asari Takada, Kazuaki Hiramatsu, Trieu Anh Ngoc, Masayoshi Harada and Toshinori Tabata, Development of a mesh-based distributed runoff model incorporated with tank models of several land utilizations in a Southeast Asian watershed, Proceedings of 21st Congress of International Association for Hydro-Environment Engineering and Research (IAHR), Asia Pacific Division (APD), 539-547, 2018.09, We propose a new long-term rainfall-runoff model for a Southeast Asian watershed. To reflect the impact of land use changes associated with rural development, and the nonuniformity of rainfall in tropical regions, a mesh-based distributed runoff model was constructed. Four tank models (paddy, upland field, urban, and forest) were incorporated into each mesh element, to capture the outflow from different land uses. Each mesh element was connected to the river network to reproduce the rainfall-runoff flow processes. By incorporating a watershed groundwater tank, we improved the representation of the baseflow component which is important in long-term runoff analysis. To shorten the calculation time and improve the application to other watersheds, we introduced an inflow/outflow matrix that defines the direction of rainwater flow between adjacent mesh elements. The model was applied to the Dau Tieng watershed in Southern Vietnam, with an area of 2,700 km2. The model was run for the period 1999-2009, and the calculated discharge was compared with the observed values, and a good model fit was achieved. As the model represents the flow processes from rainfall to river discharge with highly versatile tank models, it can be applied to watersheds where hydrological data for model verification are scarce, which is a common issue for many developing countries in Southeast Asia..
29. Vu Thi Hoai Thu, Toshinori Tabata, Kazuaki Hiramatsu, Trieu Anh Ngoc and Masayoshi Harada, Assessing Spatial Distribution of River Water Quality in Can Gio Mangrove Forest, Proceedings of International Symposium on Lowland Technonogy (ISLT 2018), 2018.09, The Can Gio mangrove forest, located in Ho Chi Minh City in Vietnam, has been an important environmental conservation focus for this region. Over time, the Can Gio mangrove forest has been negatively affected by erosion and environmental degradation caused by climate change and human activities. In this region, the Soai Rap and Long Tau Rivers, located at the downstream end of the Saigon River Basin, significantly affect the hydrodynamic regime of their subbranches. As such, the water quality of the Soai Rap and Long Tau Rivers directly affects the environmental health of the Can Gio mangrove forest. In this study, we used different technologies to assess the water quality along the Soai Rap and Long Tau Rivers based on various water quality indices including dissolved oxygen (DO), oxidation reduction potential (ORP), turbidity, pH, and salinity. These indices were measured continuously using commercial sensors and data loggers attached to the side of a moving boat and were combined with water depth and geographic information system (GIS) location data. Additional salinity data was collected using commercial data loggers for an extended time at upstream (Phu Xuan) and midpoint (Nga Bay) locations in the Can Gio mangrove forest, and salinity profiles were developed at select points along the Soai Rap and Long Tau Rivers. Field results indicated that several water quality indices varied by spatial location. The DO ranged from 4.90 to 6.46 mg/L, depending on river location. Similarly, the pH was consistently higher than 6.90 but differed between primary and secondary river locations. The salinity also differed considerably, depending on the river cross section, river depth, and distance to the sea. Conversely, the ORP and turbidity did not differ by location but were instead affected by the river’s flow conditions and human activities..
30. Tran Tuan Thach, Masayoshi Harada, Kazuaki Hiramatsu and Toshinori Tabata, The Influence of Bottom Sediment Redox State on Water Quality Dynamics under Long-term Anoxic Conditions in an Organically Polluted Reservoir, Journal of Rainwater Catchment Systems, 24, 1, 23-31, 2018.07, This study involved regular observations for four years in the reservoir, in which overabundant organic matter was prominent due to humic acid, to evaluate the water quality dynamic near the bottom during long-term anoxic periods. Based on the temporal changes of dissolved oxygen, nitrate-nitrogen, ammonia-nitrogen, phosphate-phosphorus, sulfide, total iron ions and sulfate, this study focused specifically on the influence of the redox state of the sediment surface during the early stage of thermal stratification on the anaerobic biochemical reactions. As a result, ni-trate-nitrogen started to decrease to zero due to denitrification as soon as the anoxic sate occurred, and then both ammonia-nitrogen and phosphate-phosphorus increased linearly with time due to iron reduction after nitrate-nitrogen had decreased to zero. Sulfide began to increase linearly due to sulfate reduction as soon as nitrate-nitrogen disap-peared. Also, the initial redox state of sediment impacted on the change characteristics of phosphate-phosphorus, ammonia-nitrogen and sulfide in the points of increasing timings, duration and rates. It was concluded that our results would provide important finding about the mechanisms of aqueous environmental deterioration due to organic pollu-tion as well as beneficial information for the modification of water quality prediction model..
31. Tran Tuan Thach, Masayoshi Harada, Ayaka Oniki, Kazuaki Hiramatsu and Toshinori Tabata, Estimation of water quality dynamics under long-term anoxic state in organically polluted reservoir by field observations and improved ecosystem model, Paddy and Water Environment, https://doi.org/10.1007/s10333-018-0659-6, 16, 665-686, 2018.06, [URL], In closed water bodies with significant organic pollution, anoxification due to thermal stratifica-tion leads to the elution of nitrogen and phosphorus from the bottom sediment and the generation of sulfide, resulting in further degradation of the water environment. This study focuses on the water quality dynamics in an organically polluted reservoir exhibiting long-term anoxification using two approaches: (1) field observations of seasonal changes in vertical profiles of dissolved oxygen, nitrogen, phosphorus, and sulfide, and (2) construction of a water quality prediction mod-el based on an ecosystem model incorporated with anaerobic biochemical processes. Iron and sulfate reduction occurred simultaneously because nitrate-nitrogen was reduced by denitrifying bacteria after the anoxification, and iron reduction became the main factor of the increase in am-monium-nitrogen and phosphate-phosphorus. The redox state of the bottom sediment surface, when anoxification began to occur, greatly affected the water quality dynamics caused by gradual reductive reactions under anaerobic conditions. Furthermore, the calculation accuracy of ammoni-um-nitrogen, phosphate-phosphorus, and sulfide was highly improved by modifying the conven-tional model based on the field observations. The characteristics of water quality under anaerobic conditions were sufficiently reflected in the upgraded ecosystem model. The proposed water quali-ty prediction model could be used to quantitatively estimate the water environment dynamics in organically polluted water bodies. The model could be developed further in the future to solve the problems caused by long-term anoxification..
32. Kei Kondo, Julien Boulange, Kazuaki Hiramatsu, Thai Khanh Phong, Tsuyoshi Inoue and Hirozumi Watanabe, Development and application of a dynamic in-river agrochemical fate and transport model for simulating behavior of rice herbicide in urbanizing catchment, Agricultural Water Management, DOI 10.1016/j.agwat.2017.08.006, 193, 102-115, 2017.11.
33. Tran Tuan Thach, Masayoshi Harada, Ayaka Oniki, Kazuaki Hiramatsu and Toshinori Tabata, Experimental Study on the Influence of Dissolved Or-ganic Matter and Redox State of Bottom Sediment on Water Quality Dynamics under Anaerobic Conditions due to Organic Pollution, Paddy and Water Environment, DOI 10.1007/s10333-017-0600-4, 15, 4, 889-906, 2017.10.
34. Akihiro Fukuda, Toshinori Tabata, Yuri Honda, Kazuaki Hiramatsu and Masayoshi Harada, Impact of Large Fresh Water Discharges into Hakata Bay Due to Torrential Rain Using Nested Two-Dimensional Convective-Dispersive Model, Journal of Water Resource and Protection, DOI: 10.4236/jwarp.2017.96036 , 9, 553-565, 2017.05.
35. Toshinori Tabata, Wataru Hayashi, Emi Otsubo, Kazuaki Hiramatsu and Masayoshi Harada, Appropriate Water Quality Environment for Protecting the Coastal Ecosystem in the Ariake Sea, Japan, Proceedins of the 37th World Congress of the International Association for Hydro-Environment Engineering and Research (IAHR), Paper No. 04-18-0765, 2017.05.
36. Le Van Chinh, Kazuaki Hiramatsu, Masayoshi Harada, Ta Thi Tha, Le Phu Dong, Nguyen Trong Cuu, Truong Thi Lan, Estimation of Nitrogen Transformation in Cau River Basin, Vietnam Using a Material Flow Analysis Model, Journal of the Faculty of Agriculture, Kyushu University, 62, 1, 153-162, 2017.02.
37. Le Van Chinh, Kazuaki Hiramatsu, Masayoshi Harada, Nguyen Trong Cuu, Truong Thi Lan, Estimation of Water Environment Capacity in the Cau River Basin, Vietnam using the Streeter–Phelps Model, Journal of the Faculty of Agriculture, Kyushu University, 62, 1, 163-169, 2017.02.
38. Asari Takada, Kazuaki Hiramatsu, Trieu Anh Ngoc, Masayoshi Harada, Toshinori Tabata, Development of a Grid-based Distributed Runoff Model and Flood Scenario Analyses in Dau Tieng River Watershed, Vietnam, Journal of Rainwater Catchment Systems, 22, 2, 9-17, 2017.01.
39. Ayaka Oniki, Masayoshi Harada, Kazuaki Hiramatsu and Toshinori Tabata: Experimental Study on Dynamics of Water Qualities near Bed Material in Anoxic Water Area Focused on Nitrate Nitrogen, Journal of Rainwater Catchment Systems, 22(2), 31-39, 2017.
40. Shinji Fukuda, Kazuaki Hiramatsu, Masayoshi Harada, Assessment of depth measurement using an acoustic Doppler current profiler and a CTD profiler in a small river in Japan, Lecture Notes in Computer Science 9835, Intelligent Robotics and Applications, Springer International Publishing, 10.1007/978-3-319-43518-3_30, 308-316, 2016.08.
41. Masayoshi Harada, Yosuke Kawano, Kazuaki Hiramatsu, Toshinori Tabata: Experimental study on improvement effect of DO environment in an organic polluted water body using an underwater LED considering optical absorption property of chlorophyll a .
42. Thanh Letrung, Trieu Anh Ngoc, Kazuaki Hiramatsu, Effect of the interaction between monsoon currents and waves on the morphological processes in the Mekong River Delta Coast, Japan Agricultural Research Quarterly, 50, 2, 121-133, 2016.02.
43. Takayoshi Nishioka, Masayoshi Harada, Kazuaki Hiramatsu and Toshinori Tabata: Experimental Study on Dynamics of Water Qualities under the Anaero-bic State in an Organically Polluted Water Body, Journal of Rainwater Catchment Systems, 21(2), 13-21, 2016.2..
44. Luong Bang NGUYEN, Qiong Fang LI, Trieu Anh NGOC, Kazuaki Hiramatsu, Adaptive Neuro-Fuzzy Inference System for Drought Forecasting in the Cai River Basin in Vietnam, JOURNAL OF THE FACULTY OF AGRICULTURE KYUSHU UNIVERSITY, 60, 2, 405-415, 2015.09.
45. Luong Bang NGUYEN, Qiong Fang LI, Trieu Anh NGOC, Kazuaki Hiramatsu, Drought Assessment in Cai River Basin, Vietnam: a Comparison with Regard to SPI, SPEI, SSI, and SIDI, JOURNAL OF THE FACULTY OF AGRICULTURE KYUSHU UNIVERSITY, 60, 2, 417-425, 2015.09.
46. Shinji Fukuda, Taichi Tanakura, Kazuaki Hiramatsu, 原田 昌佳, Assessment of spatial habitat heterogeneity by coupling data-driven habitat suitability models with a 2D hydrodynamic model in small-scale streams, ECOLOGICAL INFORMATICS, 10.1016/j.ecoinf.2014.10.003, 29, 147-155, 2015.09.
47. Nguyen Viet Anh, Shinji Fukuda, Kazuaki Hiramatsu, 原田 昌佳, Sensitivity-based calibration of SWAT for hydrologic cycle simulation in the Cong Watershed, Vietnam, Water Environment Research, DOI: http://dx.doi.org/10.2175/106143015X14338845156948, 87, 8, 735-750, 2015.08.
48. Shinji Fukuda, Taichi Tanakura, Kazuaki Hiramatsu and Masayoshi Harada: Application of a two dimensional ecohydraulic model for assessing restoration scenarios in an agricultural canal, Water, Land and Environmental Engineering, Vol.83, No.3, pp.175-178, 2015.03.
49. Application of a Two Dimensional Ecohydraulic Model for Assessing Restoration Scenarios in an Agricultural Canal.
50. Toshinori Tabata, Kazuaki Hiramatsu, Masayoshi Harada, Numerical Analysis for Effective Transplant and Seabed Restoration for Recovery of Pen shell Resources in the Ariake Sea, Japan, International Journal of Environmental Science and Development, DOI: 10.7763/IJESD.2015.V6.568, 6, 2, 93-99, 2015.02.
51. Kei Kondo, Julien Boulange, Thai Khanh Phong, Kazuaki Hiramatsu, Tsuyoshi Inoue and Hirozumi Watanabe: Research background and summary of "Award in 2014 for Excellent Publication in the Journal of Pesticide Science", Journal of Pesticide Science, Vol.39, No.3, pp.134-136, 2015.02.
52. Shinji Fukuda, Luis Armando Castilla, Lorena López-Galvis, Taro Takahashi, Akihiko Kamoshita, Kensuke Okada, Kazuaki Hiramatsu, Application of Random Forests for modelling rice yield from monthly weather data in Ibague, Colombia, Proceedings of the 1st International Conference on Asian Highland Natural Resources Management,International Conference, Paper Number: , 2015.01.
53. Masayoshi Harada, Akifumi Douma and Kazuaki Hiramatsu: Short-term Prediction of Chlorophyll-a Time Series using Periodic Chaos Neural Network with Observation Noise Processing, Journal of Rainwater Catchment Systems, Vol.20, No.2, pp.53-60, 2015.01..
54. Do Thuy Nguyen, Yuichiro Yoshimura, Masayoshi Harada, Kazuaki Hiramatsu, Generation of hydrogen sulfide in the deepest part of a reservoir under anoxic water conditions, Paddy and Water Environment, DOI 10.1007/s10333-013-0412-0, 13, 1, 101-113, 2015.01.
55. Toshinori Tabata, Kazuaki Hiramatsu, Masayoshi Harada, Assessment of the Water Quality in the Ariake Sea Using Principal Component Analysis, Journak of Water Resource and Protection, DOI: 10.4236/jwarp.2015.71003, 7, 41-49, 2015.01.
56. Nguyen Viet Anh, Kazuaki Hiramatsu, Shinji Fukuda, Masayoshi Harada, Application of the SWAT model and the indicators hydrologic alteration (IHA) method to hydrologic cycle assessment in the Cong Watershed, Vietnam, Proceedings of the 8th International Symposium on the East Asian Environmental Problems (EAEP2014), 1, Paper Number 4-4-2, 2014.12.
57. Masayoshi Harada, Kazuaki Hiramatsu, Shinji Fukuda, Short-term Prediction of Chlorophyll-a in a Eutrophic Closed Water Body using Chaos Recurrent Neural Network, Proceedings of the 19th Congress of Asia and Pacific Division of the International Association of Hydraulic Engineering and Research, 1, Paper Number: Environmental Hydaulics 92, 2014.09.
58. Trieu Anh Ngoc, Dang Dong Nguyen, Vu Thi Hoai Thu, Kazuaki Hiramatsu, FRAMEWORK FOR FLOOD DAMAGE ASSESSMENT CONSIDERING ABNORMAL CONDITIONS BY USING THE HYDRAULIC AND GIS MODELING, Proceedings of JSPS Core-to-Core Program SOWAC Project 2014 Fifth Joint Seminar between Water Resources University, Vietnam and Kyushu University, Japan, 1, 80-86, 2014.08.
59. Nguyen Viet Anh, Shinji Fukuda, Kazuaki Hiramatsu, Masayoshi Harada, APPLICATION OF SWAT MODEL TO THE HYDROLOGIC CYCLE AND SEDIMMENT TRANSPORT ASSESSMENT IN THE CONG WATERSHED, VIETNAM, Proceedings of JSPS Core-to-Core Program SOWAC Project 2014 Fifth Joint Seminar between Water Resources University, Vietnam and Kyushu University, Japan, 1, 54-68, 2014.08.
60. Osama Eljamal, Kazuaki Hiramatsu, Masayoshi Harada, MODELING OF PHOSPHORUS RETENTION IN CALCIUM CARBONATE MATERIALS; MODEL APPLICATION TO COLUMN EXPERIMENTS, Proceedings of JSPS Core-to-Core Program SOWAC Project 2014 Fifth Joint Seminar between Water Resources University, Vietnam and Kyushu University, Japan, 1, 172-176, 2014.08.
61. Masayoshi Harada, Kazuaki Hiramatsu and Shinji Fukuda: Dynamics of Water Qualities under the Anaerobic and Reductive State in an Organically Polluted Closed Water Body, Journal of Rainwater Catchment Systems, Vol.20, No.1, pp.49-55, 2014.
62. Osama Eljamal, Junya Okawauchi, Kazuaki Hiramatsu, Product Rich in Phosphorus Produced From Phosphorus-Contaminated Water, Advanced Materials Research, doi:10.4028/www.scientific.net/AMR.894.261, 894, 261-265, 2014.02.
63. Bui Quoc Lap, Masayoshi Harada, Kazuaki Hiramatsu, The Initial Result of Development of k-e Model for Simulation of Hydrodynamics in Lakes Toward to Simulation of Their Water Quality, Journal of the Faculty of Agriculture, Kyushu University, 59, 1, 155-161, 2014.02.
64. Tran Thi Thanh HUE, Doan Cao SON, Nguyen Thi Lan ANH, Thi Kieu ANH, Thai Khanh PHONG, Kazuaki Hiramatsu, A Simple and Rapid Method to Measure Residue of Cefexime – a Cephalosporin Antibiotic in the Wastewater of Pharmaceutical Production Plant, Journal of the Faculty of Agriculture, Kyushu University, 59, 1, 169-175, 2014.02.
65. Nguyen Do Thuy, Masayoshi Harada, Kazuaki Hiramatsu, Shinji Fukuda, Application of a simple genetic algorithm for the calibration of aquatic ecosystem model of an agricultural pond, Paddy and Water Environment, 10.1007/s10333-012-0353-z, 12, 1, 1-15, 2014.01, In this study, we aim to construct and apply a simple genetic algorithm (SGA) to optimize a large number of parameters of an one-box ecosystem model. The ecosystem model was used to simulate the water quality over a 6-month period based on the new observation data in an agricultural pond which was strongly influenced by a green algal bloom. Of the 54 parameters in this model, 10 important parameters were initially selected for the optimization, with one other parameter being subsequently added. The SGA program was used for three purposes, namely (1) to narrow the search space for the 10 parameters, (2) to assess the influence of the additional parameter on the optimization results, and (3) to observe the distribution and convergence of the optimized values for the 10 selected parameters. In the next step, new ranges for these 10 important parameters were assigned and the SGA was applied to all 54 model parameters to seek the optimum value for each parameter. The modeling approach and the results presented here provide valuable and reliable evidences of the optimum parameters for further simulations to clarify the mechanisms of the biochemical processes in the water. © 2013 Springer Japan..
66. Trieu Anh Ngoc, Kazuaki Hiramatsu, Masayoshi Harada, Optimizing the rule curves of multi-use reservoir operation using a genetic algorithm with a penalty strategy, Paddy and Water Environment, 10.1007/s10333-013-0366-2, 12, 1, 125-137, 2014.01, This study aims to propose a methodology for establishing the optimal rule curves of reservoir operation based on a multi-use reservoir system. Located on the upper Saigon River, Dau Tieng Reservoir plays an important role in economic and social aspects: (1) flood control; (2) domestic and industrial demands; (3) flushing out salt water intrusion from the downstream area; and (4) agriculture irrigation. We propose a reservoir operation model using a constrained genetic algorithm (CGA), in which the fitness function was constrained by penalty functions. The proposed model was formulated by including various water demands configured into the objective function. The penalty functions were designed for various constraints and integrated into the objectives of the operation process to perform the fitness function. The model's performance was simulated for the last 20 years with 1-month intervals and evaluated through a generalized shortage index (GSI). The derived results of three CGA cases with associated environmental flow requirements significantly improved the efficiency and effectiveness of water supply capability to various water demands as compared to current operation. Among the three cases, CGA case 3 achieved much better water releases from the reservoir as indicated by a small derived GSI value (0.33), the smallest shortage of environmental water (0.11 m3/s) and the highest water usage (63.8 %). Thus, the derived results of CGA case 3 were presented as the best rule curves for reservoir operation. To summarize, CGA was demonstrated as an effective and powerful tool for optimal strategy searching for multi-use reservoir operations. © 2013 Springer Japan..
67. Masayoshi Harada, Akifumi Douma, Kazuaki Hiramatsu, Do Thuy Nguyen, Atsushi Marui, Analysis of Seasonal Changes of Water Qualities in Eutrophic Reservoirs in Flat Low-lying Agricultural Area Using an Algae-considered Ecosystem Model, Irrigation and Drainage, DOI: 10.1002/ird.1770, 62, S1, 24-35, 2013.10.
68. Masayoshi Harada, Takafumi Tominaga, Kazuaki Hiramatsu, Atsushi Marui, Real-time Prediction of Chlorophyll-a Time Series in a Eutrophic Agricultural Reservoir in a Coastal Zone using Recurrent Neural Networks with Periodic Chaos Neurons, Irrigation and Drainage, DOI: 10.1002/ird.1757, 62, S1, 36-43, 2013.10.
69. Nguyen Manh Hung, Le Van Chinh, Kazuaki Hiramatsu, Masayoshi Harada, Dao Ngoc Tuan, Flood Inundation Analysis using a Distributed Tank Model for a Flat, Low-Lying Agricultural Area Undergoing Urbanization in Hanoi, Vietnam, Irrigation and Drainage, DOI: 10.1002/ird.1769, 62, S1, 52-64, 2013.10.
70. Trieu Anh Ngoc, Thanh Letrung, Kazuaki Hiramatsu, Thai Quyet Nguyen, The Effect of Simulated Sea Level on the Sedimentation of the Tien River Estuaries, Lower Mekong River, Southern Vietnam, Japan Agricultural Research Quarterly, 47, 4, 405-415, 2013.10.
71. Kazuaki Hiramatsu, Mathematical Tools for Water Environment Conservation from a View Point of Integrated Watershed Management, Proceedings of JSPS Core-to-Core Program SOWAC Project 2013 Third Joint Seminar between Water Resources University, Vietnam and Kyushu University, Japan, 2-2, 2013.08.
72. Nguyen Do Thuy, Masayoshi Harada, Kazuaki Hiramatsu, GENERATION OF HYDROGEN SULFIDE IN THE DEEPEST PART OF A RESERVOIR UNDER ANOXIC WATER CONDITIONS, Proceedings of JSPS Core-to-Core Program SOWAC Project 2013 Third Joint Seminar between Water Resources University, Vietnam and Kyushu University, Japan, 222-222, 2013.08.
73. Trieu Anh Ngoc, Kazuaki Hiramatsu, Masayoshi Harada, DEVELOPMENT OF MATHEMATICAL MODEL FOR OPTIMIZING OPERATION OF MULTI-PURPOSE RESERVOIR IN BALANCE OF HUMAN AND ENVIRONMENT FLOW REQUIREMENTS, Proceedings of JSPS Core-to-Core Program SOWAC Project 2013 Third Joint Seminar between Water Resources University, Vietnam and Kyushu University, Japan, 222-222, 2013.08.
74. Osama Eljamal, Junya Okawauchi, Kazuaki Hiramatsu, SOIL COLUMN EXPERIMENTS TO STUDY THE REMOVAL OF PHOSPHORUS FROM WATER, Proceedings of JSPS Core-to-Core Program SOWAC Project 2013 Third Joint Seminar between Water Resources University, Vietnam and Kyushu University, Japan, 92-95, 2013.08.
75. Toshinori Tabata, Kazuaki Hiramatsu, Masayoshi Harada, Michinobu Hirose, Numerical analysis of convective dispersion of pen shell Atrina pectinata larvae to support seabed restoration and resource recovery in the Ariake Sea, Japan, Ecological Engineering, http://dx.doi.org/10.1016/j.ecoleng.2013.04.018, 57, 154-161, 2013.05.
76. Bui Quoc Lap, Harada Masayoshi, Kazuaki Hiramatsu, Dynamics of Water Quality in the Truc Bach Lake, Hanoi Capital, Vietnam, Bui Quoc Lap, Masayoshi Harada and Kazuaki Hiramatsu, 47, 1, 85-96, 2013.02.
77. Thai Khanh Phong, Dam Hoang Phuc, Thai Ha Phi, Kazuaki Hiramatsu, Measuring Load of Phosphate in the Environment by Passive Sampling Techniques – An Introduction, Journal of the Faculty of Agriculture, Kyushu University, 58, 1, 153-157, 2013.02.
78. Haruka Iseri, Kazuaki Hiramatsu and Masayoshi Harada: Application of Distributed Nitrogen and Phosphorus Runoff Model to the Urbanizing Zuibaiji River Watershed, Transactions of the Japanese Society of Irrigation, Drainage and Rural Engineering, 81(1), pp.99-110, 2013.
79. Lap Bui Quoc, Harada Masayoshi, Hiramatsu Kazuaki, 原田 昌佳, 平松 和昭, Dynamics of Water Quality in the Truc Bach Lake, Hanoi Capital, Vietnam, 九州大学大学院農学研究院紀要, 58, 1, 145-151, 2013.02, Hanoi, the 1,000–year–old capital of Vietnam, has over 100 lakes which play a very important role in creating the landscape, as well as being the habitat for a variety of aquatic animals. However, as closed bodies of water, these lakes are facing a wide range of water quality problems due to their poor rate of exchange with external water sources. Thermal stratification, in particular, which is highly dependent upon meteorological conditions, has a great impact on the quality of their water. To gain insight into this problem, Truc Bach Lake, which is located in the northwest of Hanoi's central region, was chosen as a typical lake that would thus be a favorable place to conduct a case study. In our research, the water quality variables of Truc Bach Lake during its daily cycle were measured on site and were sampled periodically (over four seasons) for laboratory analysis, in order to investigate the vertical dynamics of its water quality during a daily cycle, as well as the seasonal changes that take place in a single year. The results of this study provide much valuable information on the temporal and spatial changes of the lake's water quality over the course of a year. They also provide a foundation for the simulation of the water quality dynamics in the targeted lake, which would provide a useful basis for further research..
80. Le Van Chinh, Haruka Iseri, Kazuaki Hiramatsu, Harada Masayoshi, Makito Mori, Simulation of Rainfall Runoff and Pollutant Load for Chikugo River Basin in Japan Using GIS-based Distributed Parameter Model, Paddy and Water Environment, 10.1007/s10333-011-0296-9, 11, 1-4, 97-112, 2013.01.
81. Trieu Anh Ngoc, Kazuaki Hiramatsu, Harada Masayoshi, Optimizing Parameters for Two Conceptual Hydrological Models Using a Genetic Algorithm: A Case Study in the Dau Tieng River Watershed, Vietnam, Japan Agricultural Research Quarterly, 47, 1, 85-96, 2013.01.
82. Toshinori Tabata, Kazuaki Hiramatsu, Masayoshi Harada and Shinji Fukuda: A Study of Resource Conservation in the Ariake Sea Using a Two-Dimensional Convective-Dispersion Model, Proceedings of 2012 Annual Conference of Applied Hydrailics Research Divison of the Japanese Society of Irrigation, Drainage and Rural Engineering, pp.53-59, 2012.
83. Kei Kondo, Julien Boulange, Thai Khanh Phong, Kazuaki Hiramatsu, Tsuyoshi Inoue, Hirozumi Watanabe, Probabilistic assessment of herbicide runoff from Japanese rice paddies: The effects of local meteorological conditions and site-specific water management, Journal of Pesticide Science, 10.1584/jpestics.D11-058, 37, 4, 312-322, 2012.12.
84. Trieu Anh Ngoc, Kazuaki Hiramatsu, Harada Masayoshi, Optimal Operation of Multi-purpose Reservoir by Constrained Genetic Algorithms, Proceedings of the 6th International Symposium on the East Asian Environmental Problems (EAEP2012), 136-147, 2012.11.
85. Thai Khanh Phong, Tsuyoshi Inoue, Katsunori Yoshino, Kazuaki Hiramatsu, Dang Thi Tuyet Nhung, Temporal trend of pesticide concentrations in the Chikugo River (Japan) with changes in environmental regulation and field infrastructure, Agricultural Water Management, 10.1016/j.agwat.2012.07.002, 113, 96-104, 2012.10.
86. Toshinori Tabata, Kazuaki Hiramatsu, Harada Masayoshi, Optimal Configuration of Nori Aquafarming Grounds in the Ariake Sea using a Two-dimensional Convective-Dispersion Model and an index of Nitrogen Assimilation Rates, Proceedings of the 4th International Conference on Estuaries and Coasts, ICEC2012, 1, 269-276, 2012.10.
87. Yuri Honda, Kazuaki Hiramatsu, Harada Masayoshi, Comparative Study on Two Nesting Techniques of Overlap and Sponge-Layer in Two-dimensional Numerical Calculations of Tidal Currents in Coastal Waters , Proceedings of the 4th International Conference on Estuaries and Coasts, ICEC2012, 1, 277-283, 2012.10.
88. Junya Okawauchi, Osama Eljamal, Kazuaki Hiramatsu and Masayoshi Harada: Phosphorus Adsorption from Aqueous Solution Using Natural Materials, Science Bulletin of the Faculty of Agriculture, Kyushu University, 67(2), pp.59-68, 2012.
89. Shinji FUKUDA, Maho Kiyota, Shinya Masuda, Shun-ichiro Ishibashi, Kazuaki Hiramatsu, Harada Masayoshi, Diel Change of Habitat Preference of Japanese Medaka (Oryzias Latipes), Proceedings of the 9th International Symposium on Ecohydraulics (ISE 2012), Paper Number 15540, 2012.09.
90. Taichi Tanakura, Shinji FUKUDA, Kazuaki Hiramatsu, Harada Masayoshi, Effect of Variable Species Distribution Models on the Evaluation of Habitat Suitability for Japanese Medaka (Oryzias Latipes), Proceedings of the 9th International Symposium on Ecohydraulics (ISE 2012), Paper Number 16633, 2012.09.
91. Nguyen Manh Hung, Le Van Chinh, Kazuaki Hiramatsu, Harada Masayoshi, Dao Ngoc Tuan, Scenario Analyses of Flood Inundation Using a Distributed Tank Model in an Urbanizing Agricultural Area of Song Nhue Hydraulic Structure Scheme in Hanoi, Proceedings of the Joint Symposium between Kyushu University and Hanoi University of Agriculture - Innovative Approaches to Land, Water and Environmenttal Research in Vietnam and Japan, 122-129, 2012.09.
92. Do Thuy Nguyen, Yuichiro Yoshimura, Harada Masayoshi, Kazuaki Hiramatsu, Simulating Mechanism of Acid-votile Sulfide in a Regulating Pond with Scarce Underwater Light Environment, Proceedings of JSPS Core-to-Core Program SOWAC Project 2012 First Joint Seminar between Water Resources University, Vietnam and Kyushu University, Japan, 86-91, 2012.08.
93. ELJAMAL OSAMA, Junya Okawauchi, Kazuaki Hiramatsu, Harada Masayoshi, An Investigation of Phosphorus Removal from Aqueous Solution using Byproduct Materials, Proceedings of JSPS Core-to-Core Program SOWAC Project 2012 First Joint Seminar between Water Resources University, Vietnam and Kyushu University, Japan, 82-85, 2012.08.
94. Yuri Honda, Kazuaki Hiramatsu and Masayoshi Harada: Application of One-way-nesting Technique on Tidal Current Simulation in Coastal Waters using a Two-dimensional Shallow Water Model, Science Bulletin of the Faculty of Agriculture, Kyushu University, 67(1), pp.9-23, 2012.2.
95. Kiroku Masuno, Masayoshi Harada, Kazuaki Hiramatsu and Atsushi Marui: Quantitative Evaluation of Seasonal Fluctuations in Water Quality in Eutrophic Reservoirs using Self-Organizing Maps, Science Bulletin of the Faculty of Agriculture, Kyushu University, 67(1), pp.25-33, 2012.2.
96. Thai Khanh Phong, Dam Hoang Phuc, Le Anh Tuan, Thai Ha Phi and Kazuaki Hiramatsu, Applications of Passive Sampling Techniques in Monitoring Organic Pollutants in the Environment, Journal of the Faculty of Agriculture, Kyushu University, 57, 1, 169-174, 2012.02.
97. Nguyen Manh Hung, Le Van Chinh, Kazuaki Hiramatsu, Masayoshi Harada and Dao Ngoc Tuan, Flood Inundation Analysis Using a Distributed Tank Model in an Urbanizing Agricultural Area of Song Nhue Hydraulic Structure Scheme in Hanoi, Proceedings of the 5th International Symposium on the East Asian Environmental Problems (EAEP2011), 235-240, 2011.11.
98. Trieu Anh Ngoc, Kazuaki Hiramatsu and Masayoshi Harada, Optimization of Parameters for Two Conceptual Hydrological Models by using a Genetic Algorithm, Proceedings of the 5th International Symposium on the East Asian Environmental Problems (EAEP2011), 241-246, 2011.11.
99. Nguyen Thuy Do, Kazuaki Hiramatsu and Masayoshi Harada, Application of Simple Genetic Algorithms for Calibrating an Aquatic Ecosysytem Model, Proceedings of the 5th International Symposium on the East Asian Environmental Problems (EAEP2011), 247-251, 2011.11.
100. Le Van Chinh, Haruka Iseri, Kazuaki Hiramatsu, Masayoshi Harada and Makito Mori, Simulation of Raifall Runoff and Pollutant Load using a GIS-based Distributed Parameter Model, a Case Study in Chikugo River Basin in Japan, Proceedings of the 5th International Symposium on the East Asian Environmental Problems (EAEP2011), 253-258, 2011.11.
101. Joko Sujono, Naoki Matsuo, Kazuaki Hiramatsu and Toshihiro Mochizuki, Improving the water productivity of paddy rice (Oryza sativa L.) cultivation through water saving irrigation treatments, Agricultural Sciences, 10.4236/as.2011.24066, 2, 4, 511-517, 2011.11.
102. Trieu Anh Ngoc, Kazuaki Hiramatsu, Le Van Duc and Nguyen Trung Quan: Procedure Development for Parameter Optimization of Hydrological Tank Model using a Genetic Algorithm, Journal of Water Resources and Environmental Engineering, 35, pp.124-130, 2011.
103. Trieu Anh Ngoc, Le Van Chinh, Kazuaki Hiramatsu and Masayoshi Harada, Parameter Identification for Two Conceptual Hydrological Models of Upper Dau Tieng River Watershed in Vietnam, Journal of the Faculty of Agriculture, Kyushu University, 56, 2, 335-341, 2011.10.
104. Toshinori Tabata, Kazuaki Hiramatsu, Masayoshi Harada, Hideto Shiraishi and Toshio Shuto: Appropriate Arrangement of Nori Aquafarming Grounds in the Ariake Sea on the Basis Convective Dispersion Simulation Model, Transactions of the Japanese Society of Irrigation, Drainage and Rural Engineering, 79(4), pp.303-310, 2011.
105. Shinji Fukuda, Bernard De Baets, Ans M. Mouton, Willem Waegeman, Jun Nakajima, Takahiko Mukai, Kazuaki Hiramatsu and Norio Onikura, Effect of model formulation on the optimization of a genetic Takagi-Sugeno fuzzy system for fish habitat suitability evaluation, Ecological Modelling, 222, 1401-1413, 2011.04.
106. Shinji Fukuda, Shinya Masuda, Kazuaki Hiramatsu and Masayoshi Harada: Assessing the effects of data types and categorization methods on HSI-based habitat suitability analysis for Japanese medaka (Oryzias latipes), Transactions of Japanese Society of Irrigation, Drainage and Rural Engineering, 79(2), pp.11-19, 2011.
107. Haruka Iseri, Kazuaki Hiramatsu and Masayoshi Harada: Nitrogen and Phosphorous Load Runoff Analysis by a GIS-based Distributed Model for Chikugo River Watershed, Transactions of Japanese Society of Irrigation, Drainage and Rural Engineering, 79(2), pp.53-63 2011.
108. HSIモデルを用いたメダカの生息場選好性評価におけるデータ形式およびカテゴリー化手法の影響.
109. Thai Khanh Phong,Kazuaki Hiramatsu and Hirozumi Watanabe, Simulating concentration of bensulfuron-methyl in a drainage canal of a paddy block by a rice pesticide model, Environmental Technology, 32, 1, 69-81, 2011.01.
110. Do Thuy Nguyen, Masayoshi Harada and Kazuaki Hiramatsu, Evaluation of the water-quality dynamics in a eutrophic agricultural pond by using a one-box ecosystem model considering several algal groups, Paddy and Water Environment, 8, 4, 301-318, 2010.12.
111. Yuichiro Yoshimura, Masayoshi Harada, Kazuaki Hiramatsu and Atsushi Marui: Quantification of Water Environment in the no. 5 Regulation Pond in the Ito Campus, Kyushu University, Science Bulletin of the Faculty of Agriculture, Kyushu University, 65(2), pp.57-72, 2010.12.
112. Akifumi Douma, Masayoshi Harada, Kazuaki Hiramatsu and Atsushi Marui: Dynamic Analysis of Chlorophyll-a and Nutrients in Eutrophic Reservoirs by using a Water Quality Model Based on Species Composition of Algae, Science Bulletin of the Faculty of Agriculture, Kyushu University, 65(2), pp.73-89, 2010.10.
113. Toshinori Tabata, Kazuaki Hiramatsu and Masayoshi Harada: Numerical Simulations of Tidal Currents in the Ariake Sea Coastal Waters by Considering Nori Aquafarming Grounds, Science Bulletin of the Faculty of Agriculture, Kyushu University, 65(2), pp.91-105, 2010.10.
114. Thai Khanh Phong, Son Hong Vu, Satoru Ishihara, Kazuaki Hiramatsu and Hirozumi Watanabe, Exposure risk assessment and evaluation of the best management practice for controlling pestiside runoff from paddy fields. Part 2: Model simulation for the herbicide pretilachlor, Pest management science, 67, 70-76, 2010.11.
115. Masayoshi Harada, Kazuaki Hiramatsu, Do Thuy Nguyen and Akifumi Douma, Numerical Simulation of Water Quality in a Eutrophic Reservoir using an Ecosystem Model considering Species Composition of Algae, Proceedings of Joint Symposium on Integrated Water and Soil Management between Water Resources University, Vietnam and Kyushu University, Japan, 1-8, 2010.11.
116. Do Thuy Nguyen, Masayoshi Harada and Kazuaki Hiramatsu, Application of Simple Genetic Algorithm for calibrating an Aquatic Ecosystem Model, Proceedings of 3rd IWA Asia Pacific Young Water Professionals Conference, Achieving Sustainable Development in the New Era, CD-Paper No.YWP006-FPV, 2010.11.
117. Le Van Chinh, Haruka Iseri, Kazuaki Hiramatsu and Masayoshi Harada, A GIS-based Distributed Parameter Model for Rainfall Runoff Calculation using Arc Hydro Tool and Curve Number Method for Chikugo River Basin in Japan, Journal of the Faculty of Agriculture, Kyushu University, 55, 2, 313-319, 2010.10.
118. Thai Khanh Phong, Katsunori Yoshino, Kazuaki Hiramatsu, Masayoshi Harada and Tsuyoshi Inoue, Behavior of Pretilachlor and Dimethametryn in Water of Flooded Rice FieldsJ, Journal of the Faculty of Agriculture, Kyushu University, 55, 2, 321-326, 2010.10.
119. Le Van Chinh, Kazuaki Hiramatsu, Masayoshi Harada and Makito Mori, Mathematical Modeling of Surface Water Quantity and Quality for Optimal Management of Water Resources in a Flat Low-lying Agricultural Area, Proceedings of Hydrology Conference 2010, The Changing Physical and Social Environment: Hydrologic Impacts and Feedbacks, CD-Paper No.P1.16, 2010.10.
120. Shinya Masuda, Shinji Fukuda, Kazuaki Hiramatsu and Masayoshi Harada, Habitat suitability analysis for Japanese medaka (Oryzias latipes) using presence-absence data with four different categorization approaches, Proceedings of the 8th International Symposium on Ecohydraulics 2010, Bridging between Ecology and Hydraulics and Leading the Society's New Need - Living with Nature, CD-Paper No.S5B-2, 2010.09.
121. Thai Khanh Phong, Katsunori Yoshino, Kazuaki Hiramatsu, Masayoshi Harada and Tsuyoshi Inoue, Pestiside discharge and water management in a paddy catchment in Japan, Paddy and Water Environment, 8, 4, 361-369, 2009.12.
122. Katsunori Yoshino, Thai Khanh Phong,Kazuaki Hiramatsu,Masayoshi Harada,Kei Kondo, Hirozumi Watanabe and Tsuyoshi Inoue, Water management and water balance estimation in a paddy block: A case study in Kurume City, Fukuoka, Proceedings of the 6th Japan-Korea International Joint Symposium, CD-Paper No.P-26KU, 2009.11.
123. Do Thuy Nguyen, Masayoshi Harada and Kazuaki Hiramatsu, Numerical Simulation of Water Quality in an Agricultural Pond using a One-box Ecosystem Model, Proceedings of the 6th Japan-Korea International Joint Symposium, CD-Paper No.WS2A-1KU, 2009.11.
124. Thai Khanh Phong, Kazuaki Hiramatsu, Son Hong Vu, Satoru Ishihara and Hirozumi Watanabe, Simulation of Pesticide Behavior in a Paddy Block by a Pesticide Fate and Transport Model, Journal of the Faculty of Agriculture, Kyushu University, 54, 2, 505-512, 54(2), pp.505-512, 2009.10.
125. Thai Khanh Phong, Dang Thi Tuyet Nhung, Kazuaki Hiramatsu and Hirozumi Watanabe, Prediction of the Fate of Oxytetracycline and Oxolinic Acid in a Fish Pond Using Simulation Model – A Preliminary Study, Journal of the Faculty of Agriculture, Kyushu University, 54, 2, 513-522, 54(2), pp.513-522, 2009.10.
126. Takafumi Tominaga, Masayoshi Harada, Kazuaki Hiramatsu and Atsushi Marui:Time Series Analysis of Chlorophyll-a Concentration considering Algae Class in a Eutrophic Water Body using Discrete Wavelet Transform, Science Bulletin of the Faculty of Agriculture, Kyushu University, 64(2), pp.125-134, 2009.10.
127. Shinya Masuda, Masayoshi Harada, Kazuaki Hiramatsu and Atsushi Marui:Formulation of Water Quality Prediction Model Considering Several Species of Phytoplankton, Science Bulletin of the Faculty of Agriculture, Kyushu University, 64(2), pp.135-146, 2009.10.
128. Ichiro Nakashima, Haruka Iseri, Taisuke Fukata, Kazuaki Hiramatsu, Masayoshi Harada and Phong Khanh Thai:Application of a GIS-based Pesticide Runoff Model to Chikugo River Basin, Science Bulletin of the Faculty of Agriculture, Kyushu University, 64(2), pp.147-160, 2009.10.
129. Thai Khanh Phong,Hirozumi Watanabe and Kazuaki Hiramatsu, Uncertainties in modelling pesticide losses from rice fields to an adjacent drainage canal, Proceedings of of the 12th IUPAC International Congress of Pesticide Chemistry, Abstract Number 466, 2009.07.
130. Le Van Chinh, Kazuaki Hiramatsu, Masayoshi Harada and Makito Mori, Estimation of Water Levels in a Main Drainage Canal in a Flat Low-lying Agricultural Area Using Artificial Neural Network Models, Agricultural Water Management, No.96, pp.1332-1338, 2009.06.
131. Masayoshi Harada, Kazuaki Hiramatsu, Takashi Saitoh, Makito Mori and Atsushi Marui: Dynamics of Water Qualities in a Eutrophic Water Body under Scarce Underwater Light Environment, Journal of Rainwater Catchment Systems, 14(2), pp.87-96, 2009.1.
132. Le Van Chinh, Kazuaki Hiramatsu, Masayoshi Harada and Makito Mori, Nitrogen and Phosphorus Runoff Modeling in a Flat Low-lying Paddy Cultivated Area, Paddy and Water Environment, 6(4), pp.405-414, 2008.12.
133. Le Van Chinh, Kazuaki Hiramatsu, Masayoshi Harada and Makito Mori, Numerical Modeling of Nitrogen and Phosphorus in a Flat Low-Lying Paddy Cultivated Area, Proceedings of the JSPS International Seminar 2008 "Hybrid Rice and Transformation of Farming Systems", pp.152-159, 2008.11.
134. Haruka Iseri, Masayoshi Harada, Kazuaki Hiramatsu, Makito Mori and Atsusshi Marui: Evaluation of Water Quality Environment in Eutrophic Reservoirs using an Ecosystem Model, Science Bulletin of the Faculty of Agriculture, Kyushu University, 63(2), pp.147-160, 2008.10.
135. Akiko Matsumoto, Masayoshi Harada, Kazuaki Hiramatsu, Makito Mori and Atsushi Marui: Evaluations of Aquatic Environment in Eutrophic Reservoirs Based on the Seasonal Change in Phytoplankton and Zooplankton, Science Bulletin of the Faculty of Agriculture, Kyushu University, 63(2), pp.161-177, 2008.10.
136. Le Van Chinh, Kazuaki Hiramatsu, Masayoshi Harada and Makito Mori, Optimal Gate Operation of a Main Drainage Canal in a Flat Low-lying Agricultural Area using a Tank Model, Paddy and Water Environment, 6(3), pp.243-256, 2008.09.
137. Shinji Fukuda and Kazuaki Hiramatsu, Prediction ability and sensitivity of artificial intelligence-based habitat preference models for predicting spatial distribution of Japanese medaka (Oryzias latipes), Ecological Modelling, 215(4), pp.301-313, 2008.06.
138. Koji Sai, Masayoshi Harada, Kazuaki Hiramatsu and Makito Mori: Numerical Analysis of Disolved Oxygen Behavior in Lake Togo using 3-dimensional Eco-hydrodynamic Model, Transactions of the Japanese Society of Irrigation, Drainage and Rural Engineering, 76(3), pp.31-40, 2008.6.
139. Makito Mori, Kazuaki Hiramatsu, Masayoshi Harada and Le Van Chinh, Estimation of Potential Evapotranspiration in a Flat, Low-Lying Area Using Routine Meteorological Data, Abstract book of the International Symposium on Agricultural Meteorology ISAM2008, p.116, 2008.03.
140. Makito Mori, Kazuaki Hiramatsu and Masayoshi Harada, Relationship between GPS-derived Precipitable Water Vapor and Surface Vapor Pressure under Low-humidity Conditions, Abstract book of the International Symposium on Agricultural Meteorology ISAM2008, p.117, 2008.03.
141. Masayoshi HARADA, Koji SAI, Masako MISHIMA, Isao YOSHIDA, Kazuaki HIRAMATSU and MAkito MORI: On the Formation and Destructive Process of Density Stratification in Lake Koyama, Transactions of the Japanese Society of Irrigation, Drainage and Reclamation Engineering, 75(5), pp.107-115, 2007.10.
142. Koji SAI, Masayoshi HARADA, Isao YOSHIDA, Kazuaki HIRAMATSU and Makito MORI, Application of Artificial Neural Network Models to the Estimation of Chlorophyll a Concentration in Lake Koyama, Tottori Prefecture, Japan, Journal of the Faculty of Agriculture, Kyushu University, 52(2), pp.405-409, 2007.10.
143. Le Van CHINH, Kazuaki HIRAMATSU, Masayoshi HARADA and Makito MORI, Mathematical Simulation for Flood Inundation and Gate Operation of a Main Drainage Canal in a Flat Low-lying Agricultural Area, Journal of the Faculty of Agriculture, Kyushu University, 52(2), pp.411-422, 2007.10.
144. Hour IX, Kazuaki HIRAMATSU, Masayoshi HARADA and Makito MORI, Water Quality Conservation in an Agricultural Pond using an Ecosystem Model and Scenario Analysis, Journal of the Faculty of Agriculture, Kyushu University, 52(2), pp.423-429, 2007.10.
145. Hour IX, Makito MORI, Kazuaki HIRAMATSU and Masayoshi HARADA, GIS-based Watershed Management Modeling for Surface Runoff Calculation in Tatara River Basin, Japan, Journal of the Faculty of Agriculture, Kyushu University, 52(2), pp.431-438, 2007.10.
146. Ichiro NAKASHIMA, Masayoshi HARADA, Kazuaki HIRAMATSU, Makito MORIm, Toshihiro MOCHIZUKI and Naoki MATSUO: Evaluation of Runoff Characteristic of Rice Herbicides from a Paddy Field using Paddy Model, Science Bulletin of the Faculty of Agriculture, Kyushu University, 62(2), pp.19-30, 2007.10.
147. Tatsuya YAMAMOTO, Masayoshi HARADA, Kazuaki HIRAMATSU and Makito MORI: Scenario Analyses of Water Quality Environment in an Agricultural Pond using a Primary Ecosystem Model, Science Bulletin of the Faculty of Agriculture, Kyushu University, 62(2), pp.31-42, 2007.10.
148. Makito MORI, Kazuaki HIRAMATSU and Masayoshi HARADA: Estimating Daily Potential Evapotranspiration using the Relation between GPS-derived Precipitable Water Vapor and Surface Temperature, Transactions of the Japanese Society of Irrigation, Drainage and Reclamation Engineering, 75-4, pp.1-6, 2007.8
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149. Makito MORI, Kazuaki HIRAMATSU and Masayoshi HARADA: Estimation of Monthly Potential Evapotranspiration using GPS-derived Precipitable Water Vapor, Transactions of the Japanese Society of Irrigation, Drainage and Reclamation Engineering, 75-4, pp.7-15, 2007.8
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150. Makito MORI, Hironobu TANAKA, Kazuaki HIRAMATSU and Masayoshi HARADA: Examination of an Index for Predicting Heavy Precipitation using GPS-derived Precipitable Water Vapor, Transactions of the Japanese Society of Irrigation, Drainage and Reclamation Engineering, 75-4, pp.17-25, 2007.8
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151. Koji SAI, MAsayoshi HARADA, Isao YOSHIDA, Kazuaki HIRAMATSU and Makito MORI: Real-time Prediction of Dissolved Oxygen in Eutrophic Lake using Feedback Artificial Neural Network Models, Transactions of the Japanese Society of Irrigation, Drainage and Reclamation Engineering, 75-2, pp.47-54, 2007.4
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152. Koji SAI, MAsayoshi HARADA, Isao YOSHIDA, Kazuaki HIRAMATSU and Makito MORI: Estimation of Chlorophyll a Concentration in an Eutrophic Lake with Artificial Neural Network Models, Transactions of the Japanese Society of Irrigation, Drainage and Reclamation Engineering, 75-4, pp.57-64, 2007.8
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153. Shinji Fukuda and Kazuaki Hiramatsu, Prediction Ability of Resource Selection Functions for the Estimation of Fish Habitat Preference, Transactions of the Japanese Society of Irrigation, Drainage and Reclamation Engineering, 75(1), pp.113-118, 2007.02.
154. Shinji FUKUDA, Kazuaki HIRAMATSU and Shuji OKUSHIMA, An information-theoretic approach for the model selection in habitat preference evaluation of Japanese medaka (Oryzias latipes), Bulletin of the Institute of Tropical Agriculture Kyushu University, 29(2), pp.105-118, 2006.12.
155. Masayoshi HARADA, Mayumi FUKUDA, Koji SAI, Isao YOSHIDA, Kazuaki HIRAMATSU and Makito MORI: Short-term prediction of Dissolved Oxygen in eutrophic lake by local approximation method incorporated with wavelet analysis, Transactions of the Japanese Society of Irrigation, Drainage and Reclamation Engineering, 74(6),pp.139-149, 2006.12.
156. Hideaki TASAI, Kazuaki HIRAMATSU, Makito MORI and Masayoshi HARADA: Characteristics evaluation of TOPMODEL parameters using SCE-UA method, Science Bulletin of the Faculty of Agriculture, Kyushu University, 61(2), pp.261-272, 2006.11
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157. Kyohei SAKAKI, Masayoshi HARADA, Koji SAI, Isao YOSHIDA, Kazuaki HIRAMATSU and Makito MORI: Numerical Simulation of Water Motion and Salinity Diffusion in Lake Togo by Two-dimensional One-layer Model, Science Bulletin of the Faculty of Agriculture, Kyushu University, 61(2), pp.273-280, 2006.11.
158. Koji SAI, Masayoshi HARADA, Isao YOSHIDA, Kazuaki HIRAMATSU and Makito MORI: Numerical Simulation of Water Motion in Lake Koyama by Two-dimensional One-layer Model with ADI method, Science Bulletin of the Faculty of Agriculture, Kyushu University, 61(2), pp.281-288, 2006.11.
159. Masao KAMIYA, Kazuaki HIRAMATSU, Masayoshi HARADA and Makito MORI: A three-dimensional sigma-coordinate ocean model with a wetting and drying scheme and its application to Isahaya Bay, Science Bulletin of the Faculty of Agriculture, Kyushu University, 61(2), pp.289-296, 2006.11.
160. Takashi SAITO, Masayoshi HARADA, Kazuaki HIRAMATSU and Makito MORI: Scenario Analyses for Nitrogen Reduction in an Agricultural Pond using One-box Ecosystem Model, Science Bulletin of the Faculty of Agriculture, Kyushu University, 61(2), pp.297-301, 2006.11.
161. Le Van CHINH, Kazuaki HIRAMATSU, Masayoshi HARADA and Makito MORI, Optimal Gate Operation of a Main Drainage Canal in a Flat Low-lying Agricultural Area using a Tank Model Incorporated with a Genetic Algorithm, Journal of the Faculty of Agriculture, Kyushu University, 51(2), PP.351-359, 2006.11.
162. Koji SAI, Masayoshi HARADA, Isao YOSHIDA, Kazuaki HIRAMATSU and Makito MORI: Short-term Prediction of Dissolved Oxygen of Lake Koyama, Tottori Prefecture, by Artificial Neural Network Model and Improvement of Prediction Accuracy by Wavelet Analysis, Applied Hydrology, 19, pp.31-40, 2006.11.
163. Shinji FUKUDA and Kazuaki HIRAMATSU: The use of Akaike information criterion for selecting optimal habitat preference model of Japanese medaka (Oryzias latipes), Applied Hydrology, 19, pp.51-61, 2006.11.
164. Makito MORI, Kazuaki HIRAMATSU and Masayoshi HARADA: Prediction of Heavy Precipitation Based on Relation Between Surface Temperature and GPS-derived Precipitable Water Vapor, Applied Hydrology, 19, pp.117-125, 2006.11.
165. Shinji FUKUDA, Kazuaki HIRAMATSU and Makito MORI, Fuzzified neural networks model for habitat evaluation procedures to estimate habitat quality for Japanese Medaka (Oryzias latipes) in agricultural canals, Paddy and Water Environment, 4(3), pp.119-124, 2006.09.
166. Shinji Fukuda, Kazuaki Hiramatsu, Makito Mori, Fuzzy neural network model for habitat prediction and HEP for habitat quality estimation focusing on Japanese medaka (Oryzias latipes) in agricultural canals, Paddy and Water Environment, 10.1007/s10333-006-0039-5, 4, 3, 119-124, 2006.09, In the field of agriculture, development of evaluation techniques for environmental changes is urgently required for the purpose of finding a balance between growth in agricultural productivity and environmental considerations. The habitat evaluation procedures (HEP) constitute one technique for habitat assessment. While HEP is widely applied to estimate both habitat quality and quantity in an environment, it appears to be necessary to develop an accurate habitat prediction model in order to evaluate environments precisely. In fact, habitat selection by fish is affected by complicated interaction between multiple environmental factors, which makes it difficult to relate physical environments to habitat preference. In the present study, we utilize artificial neural networks (ANNs), which are commonly applied to model complex systems, to predict the habitat selection of Japanese medaka (Oryzias latipes) in agricultural canals. Considering the essential vagueness of fish behavior, fuzzy membership functions are introduced into the input layer, which advances ANN to fuzzy neural network (FNN). In addition, symmetric triangular fuzzy numbers are employed to account for uncertainty in measurement errors and dispersions of physical environment. The FNN model precisely predicts the habitat preference of Japanese medaka in an agricultural canal, and the results show a good agreement between the calculated and observed habitat suitability indices (HSI). Finally, the habitat quality of two different reaches at the same point in time is compared using HEP, with a view of suitable habitat for Japanese medaka. © Springer-Verlag 2006..
167. Shinji FUKUDA, Kazuaki HIRAMATSU, Makito MORI, Masayoshi HARADA and Shiomi SHIKASHO, Model selection toward the quantification of fish habitat preference of Japanese medaka (Oryzias latipes), Proceedings of International Conference on Ecological Modelling 2006, pp.152-153, 2006.08.
168. Shinji FUKUDA, Kazuaki HIRAMATSU, Makito MORI and Shiomi SHIKASHO, Numerical quantification of the significance of aquatic vegetation affecting spatial distribution of Japanese medaka (Oryzias latipes) in an agricultural canal, Landscape and Ecological Engineering, 2(1), pp.65-80, 2006.05.
169. Makito Mori, Takamichi Mimori, Kazuaki Hiramatsu and Shiomi Shikasho: Estimation of water pressure near the ground from GPS-derived precipitable water vapor, Transactions of the Japanese Society of Irrigation, Drainage and Reclamation Engineering, 242, pp.91-97, 2006.4.
170. Koji SAI, Masayoshi HARADA, Isao YOSHIDA, Kazuaki HIRAMATSU and Makito MORI: Seasonal Variation and Spatial Distribution of Water Quality in Lake Togo, Tottori Prefecture, Transactions of the Japanese Society of Irrigation, Drainage and Reclamation Engineering, 75(1),pp.31-36, 2006.12.
171. Kazuaki HIRAMATSU, Kiyoshi KUROSAWA, Makito MORI and Shiomi SHIKASHO, Flood Inundation Analysis in a Flat Low-lying Paddy-cultivated Area of the Red River Delta, Viet Nam, Bulletin of the Institute of Tropical Agriculture Kyushu Univbersity, 28(1), pp.121-136, 2005.12.
172. Kei NAKAYAMA, Yoji OSHIMA, Kazuaki HIARMATSU, Yohei SHIMAZAKI and Tsuneo HONJO, Effects of polychlorinated biphenyls on the schooling behavior of Japanese Medaka (oryzias latipes), Environmental Toxicology and Chemistry, 10.1897/04-518R2.1, 24, 10, 2588-2593, 24(10), pp.2588-2593, 2005.11.
173. Shinji FUKUDA, Kazuaki HIARMATSU and Makito MORI: Fuzzified neural network model for habitat prediction of Japanese Medaka (Oryzias latipes) and habitat quality estimation using habitat evaluation procedures, Applied Hydrology, 18, pp.40-47, 2005.11.
174. Shinji FUKUDA, Kazuaki HIRAMATSU, Makito MORI and Shiomi SHIKASHO: Mathematical Characterization of Fuzziness in Fish Habitat Preference of Japanese Medaka (Oryzias latipes) in Agricultural Canal, Transactions of the Japanese Society of Irrigation, Drainage and Reclamation Engineering, 239, pp.43-49, 2005.11.
175. Shinji FUKUDA, Kazuaki HIRAMATSU, Makito MORI and Shiomi SHIKASHO, An Adaptive Modeling Technique for Instream Fish Habitat Preference of Japanese Medaka (Oryzias latipes), Journal of the Faculty of Agriculture, Kyushu University, 50, 2, 363-373, 50(2), pp.363-373, 2005.11.
176. Yuko OKADA, Kazuaki HIRAMATSU, Shiomi SHIKASHO and Makito MOR: Rainfall Runoff Modeling in a Small Mountainous Basin Using TOPMODEL, Science Bulletin of the Faculty of Agriculture, Kyushu University, 60(2), pp.151-163, 2005.11.
177. Koichi URANO, Shiomi SHIKASHO, Kazuaki HIRAMATSU and Makito MORI: Applicability of the Long- and Short-Term Runoff Model in a Small Mountainous Basin, Science Bulletin of the Faculty of Agriculture, Kyushu University, 60(2), pp.165-172, 2005.11.
178. Katsuichirou ABE, Shinji FUKUDA, Kazuaki HIRAMATSU, Makito MORI and Shiomi SHIKASHO: Quantification of Preference Intensity of Japanese Medaka for Environmental Factors in Agricultural Canal, Science Bulletin of the Faculty of Agriculture, Kyushu University, 60(2), pp.173-178, 2005.11.
179. Kazuaki HIRAMATSU, Yoji OSHIMA, Suguru INOUE and Shiomi SHIKASHO, Numerical modeling of environmental behavior and fate of tributyltin in a semi-closed bay, Paddy and Water Environment, 10.1007/s10333-005-0003-9, 3, 2, 79-92, 3(2), pp.72-92, 2005.06.
180. Kazuaki HIRAMATSU, Shiomi SHIKASHO and Ken MORI, Numerical prediction of suspended sediment concentration in the Ariake Sea, Japan, using time-dependent sediment resuspension and deposition model, Paddy and Water Environment, 10.1007/s10333-004-0057-0, 3, 1, 13-19, 3(1), pp.13-19, 2005.03.
181. Hideaki TASAI,Kazuaki HIRAMATSU, Makito MORI and Shiomi SHIKASHO: Long- and Short-Term Runoff Analysis in a Small Mountainous Basin Using TOPMODEL, Science Bulletin of the Faculty of Agriculture, Kyushu University, 59(2), pp.173-183, 2004.11.
182. Hironobu TANAKA,Kazuaki HIRAMATSU,Makito MORI and Shiomi SHIKASHO: Measurement Parameters of Particle Image Velocimetry (PIV) for an Open Channel Backward-Facing Step Flow, Science Bulletin of the Faculty of Agriculture, Kyushu University, 59(2), pp.165-171, 2004.11.
183. Kazuaki HIRAMATSU, Eisaku SHIRATANI and Shiomi SHIKASHO: Creek Water Quality Analysis in Flat Low-lying Paddy-cultivated Area using an Ecosystem Model, Science Bulletin of the Faculty of Agriculture, Kyushu University, 59(2), pp.153-164, 2004.11.
184. Kazuaki HIRAMATSU, Shiomi SHIKASHO, Kiyoshi KUROSAWA and Makito MORI, Drainage and Inundation Analysis in a Flat Low-lying Paddy-cultivated Area of the Red River Delta, Viet Nam, Journal of the Faculty of Agriculture, Kyushu University, 49, 2, 383-399, 49(2), pp.383-399, 2004.11.
185. Kazuaki HIRAMATSU and Shiomi SHIKASHO, GA-based model optimization for preference intensity of Japanese Medaka Fish (Oryzias latipes) to streamflow environments, Paddy and Water Environment, 10.1007/s10333-004-0052-5, 2, 3, 135-143, 2(3), pp.135-143, 2004.11.
186. Kazuaki HIRAMATSU, Shiomi SHIKASHO and Shinji FUKUDA, Mathematical Modeling of Preference Intensity of Japanese Medaka Fish for Instream Water Environment using Fuzzy Reasoning, Proceedings of the 2004 ASAE/CSAE Annual International Meeting, CD-Paper No. 43069, 2004.08.
187. Kazuaki HIRAMATSU, Yuji OSHIMA, Suguru INOUE and Shiomi SHIKASHO, Numerical modeling of environmental behavior and fate of tributyltin in a semi-closed bay, Paddy and Water Environment, 10.1007/s10333-005-0003-9, 3, 2, 79-92, 3(2), pp.79-92, 2004.06.
188. Kazuaki HIRAMATSU, Shiomi SHIKASHO and Ken MORI, Numerical prediction of suspended sediment concentration in the Ariake Sea, Japan, using time-dependent sediment resuspension and deposition model, Paddy and Water Environment, 10.1007/s10333-004-0057-0, 3, 1, 13-19, 3(1), pp.13-19, 2004.03.
189. Joko SUJONO, Shiomi SHIKASHO and Kazuaki HIRAMATSU, A comparison of techniques for hydrograph recession analysis, Hydrological Processes, 10.1002/hyp.1247, 18, 3, 403-413, Vol.18-3, pp.403-413, 2004.02.
190. Kazuaki HIRAMATSU, Shinji FUKUDA and Shjiomi SHIKASHO: Mathematical Modeling of Preference Intensity of Japanese Medaka for Instream Water Environment using Fuzzy Inference, Transactions of the Japanese Society of Irrigation, Drainage and Reclamation Engineering, 228, 2003.12.
191. Joko SUJONO, Shiomi SHIKASHO and Kazuaki HIRAMATSU, Vagueness ratio of storage function model parameters and its relation to the accuracy of hydrograph prediction, Paddy and Water Environment, 10.1007/s10333-003-0027-y, 1, 4, 201-206, Vol.1-4, pp.201-206, 2003.12.
192. Yuko OKADA, Kazuaki HIRAMATSU and Shiomi SHIKASHO: Relationship between Basin Storage and Discharge in a Small Mountainous Basin,Science Bulletin of the Faculty of Agriculture, Kyushu University, 58-1/2, pp.55-60, 2003.11.
193. Kazuaki HIRAMATSU, Shinji FUKUDA and Shiomi SHIKASHO: Fuzzy Rule-based Quantification of Preference Intensity of Japanese Medaka for Instream Water Environment, Applied Hydrology, 16, pp.18.27, 2003.10.
194. Kazuaki HIRAMATSU and Shiomi SHIKASHO, Short-term Prediction of Water-Stage Time Series in a Tidal River using a State Space Predictor, Proceedings of 2nd International Workshop on Sustainable Development of Tidal Areas, pp.43-51, 2003.09.
195. Kazuaki HIRAMATSU and Shiomi SHIKASHO, Mathematical Modeling of Preference Intensity of Japanese Medaka for Environmental Factors in Streamflow, Journal of the Faculty of Agriculture, Kyushu University, 47, 1, 109-127, Vol.47-1, pp.109-127, 2002.11.
196. Joko SUJONO, Shiomi SHIKASHO and Kazuaki HIRAMATSU, Deriving the Storage Function Model Parameters by Using Runoff Data Only, Journal of the Faculty of Agriculture, Kyushu University, 47, 1, 129-138, Vol.47-1, pp.129-138, 2002.11.
197. Kazuaki HIRAMATSU, Kei NAKAYAMA, Yuji OSHIMA, Shiomi SHIKASHO and Tsuneo HONJO: An Approach to Fish-based Biomonitoring Using Behavior Analysis of Japanese Medaka Fish, Applied Hydrology, 15, pp.88-95, 2002.10.
198. Kazuaki HIRAMATSU and Shiomi SHIKASHO, Experimental Study on the Fish Preference for Hydraulic Environments, Proceedings of the 2002 ASAE Annual International Meeting / CIGR XVth World Congress, CD-027004, 2002.07.
199. Joko SUJONO, Shiomi SHIKASHO and Kazuaki HIRAMATSU, Evaluation of the Storage Function Model Parameters Using Fuzzy Linear Regression Approach, Proceedings of the 13th Congress of the Asia and Pacific Division of the International Association for Hydraulic Engineering and Research, 675-680, pp.675-680, 2002.07.
200. Joko SUJONO, Shiomi SHIKASHO and Kazuaki HIRAMATSU, Parameter Estimation of the Storage Function Model Using Fuzzy Linear Regression Approach, COMPUTATIONAL METHODS IN WATER RESOURCES, Proceedings of the XIV International Conference on Computational Methods in Water Resources, Jun 23-28, Delft, The Netherlands, Volume 2: Edited by S. M. Hassanizadeh, R. J. Schotting, W. G. Gray and G. F. Pinder: Elsevier Science, Amsterdam, The Netherlands, 47, 1565-1572, Vol.2, pp.1565-1572, 2002.06.
201. Ken MORI, Shiomi SHIKASHO and Kazuaki HIRAMATSU, Wind-Induced Flow in a Closed-Water Area with Discrete Wind Shear, Fisheries Engineering, Vol.37-3, pp.195-201, 2002.02.
202. Kazuaki HIRAMATSU and Shiomi SHIKASHO: An Approach to Estimation of Environmental Preference of Fish from Chaos Engineering, Applied Hydrology, 14, pp.74-81, 2001.11.
203. Kazuaki HIRAMATSU, Shiomi SHIKASHO and Ken MORI, Numerical Simulations of Cohesive Sediment Transportation in Coastal Waters Considering Time-dependent Sediment Resuspension and Deposition, Journal of the Faculty of Agriculture, Kyushu University, 46, 1, 1-14, Vol.46-1, pp.1-14, 2001.11.
204. Kazuaki HIRAMATSU and Shiomi SHIKASHO: Flood Mitigation Function Estimates of a Flat Low-lying Agricultural Area along the Lower Reach of the Chikugo River, Science Bulletin of the Faculty of Agriculture, Kyushu University, 56-1, pp.1-8, 2001.11.
205. Kazuaki HIRAMATSU, Shiomi SHIKASHO and Ken MORI, Two-dimensional Numerical Modeling of Cohesive Sediment Transportation for Coastal Waters in the Ariake Sea, Japan, Proceedings of the 1st Asian Regional Conference of ICID, CD-WS-14, 2001.09.
206. Ken MORI, Shiomi SHIKASHO and Kazukai HIRAMATSU: Daily Cyclic Variations of Dissolved Oxygen in a Closed-water Area, Fisheries Engineering, 38-1, pp.53-59, 2001.6.
207. Joko SUJONO, Shiomi SHIKASHO and Kazuaki HIRAMATSU, Hydrograph Recession Analysis Using Wavelet Transforms, Journal of the Faculty of Agriculture, Kyushu University, 45, 2, 557-564, Vol.45-2, pp.557-564, 2001.02.
208. Kazuaki HIRAMATSU, Yuji OSHIMA, Shiomi SHIKASHO, Ken MORI and Suguru INOUE: Muliple-compartment Modeling of Butyltin Compounds Contamination in the Ariake Sea, Applied Hydrology, 13, pp.11-20, 2000.11.
209. Kazuaki HIRAMATSU, Shiomi SHIKASHO and Ken MORI, Simulation and Analysis of a Fish School in a Water Tank using a Behavioral Pattern Model, Proceedings of the 12th Congress of the Asia and Pacific Division ofthe International Association for Hydraulic Engineering and Research, pp.1293-1302, 2000.11.
210. Joko SUJONO, Shiomi SHIKASHO, Ken MORI and Kazuaki HIRAMATSU, Design Unit Hydrograph Procedure for Eastern New South Wales, Australia, Proceedings of the 12th Congress of the Asia and Pacific Division ofthe International Association for Hydraulic Engineering and Research, pp.863-870, 2000.11.
211. Kazuaki HIRAMATSU, Shiomi SHIKASHO and Ken MORI, Mathematical Modeling of Fish Schooling of Japanese Medaka using Basic Behavioral Patterns, Journal of the Faculty of Agriculture, Kyushu University, 45, 1, 237-253, Vol.45-1, pp. 237-253, 2000.11.
212. Kazuaki HIRAMATSU, Shiomi SHIKASHO and Ken MORI, Chaotic and Fractal Modeling of Water-Stage Time Series in a Tidal River, Journal of the Faculty of Agriculture, Kyushu University, 45, 1, 255-265, Vol.45-1, pp.255-265, 2000.11.
213. Ken MORI, Shiomi SHIKASHO, Kazuaki HIRAMATSU and Takeshi TAKEGAKI, Flow in a U-shaped Burrow, Journal of the Faculty of Agriculture, Kyushu University, 45, 1, 267-276, Vol.45-1, pp.267-276, 2000.11.
214. Kazuaki HIRAMATSU, Shiomi SHIKASHO, Ken MORI and Suguru INOUE: Numerical Simulations of the Environmental Behavior and Fate pf Butyltin Compounds in the Ariake Sea, Science Bulletin of the Faculty of Agriculture, Kyushu University, 55-1, pp.27-43, 2000.11.
215. Sayaka NISHI, Ayako SUGA, Shimomi SHIKASHO, Ken MORI and Kazuaki HIRAMATSU: Study on Aesthetic Evaluation Methods of Water Space Including Agricultural Waterway, Science Bulletin of the Faculty of Agriculture, Kyushu University, 54-3/4, pp.133-139, 2000.2.
216. Masayoshi HARADA, Kazuaki HIRAMATSU and Shizuo HAYASHI, Settling Velocity of Particles in a Grid-Generated Turbulence, Journal of the Faculty of Agriculture, Kyushu University, 44, 3-4, 385-402, Vol.44-3/4, pp.385-402, 2000.02.
217. Kazuaki HIRAMATSU, Shiomi SHIKASHO and Ken MORI, Chaotic and Fractal Modeling of Water-Stage Time Series in a Tidal River, Journal of the Faculty of Agriculture, Kyushu University, Vol.44-1/2, pp.137-147, 1999.11.
218. Kazuaki HIRAMATSU, Shiomi SHIKASHO and Ken MORI: Estimation of the Flood Mitigation Function of Agricultural Land in a Flat Low-lying Area with Creek Networks, Science Bulletin of the Faculty of Agriculture, Kyushu University, 54-1/2, pp25-33, 1999.11.
219. Kazuaki HIRAMATSU, Shiomi SHIKASHO and Ken MORI, The Use of a State Space Predictor with Local Approximation for Short-Term Predictions of River Water-stages, Proceedings of the 8th International Conference on Urban Storm Drainage, pp.2186-2193, 1999.08.
220. Masayoshi HARADA, Kazuaki HIRAMATSU, Shiomi SHIKASHO and Ken MORI: Wavelet Analysis of Dynamic Response of Floc in Turbulent Shear Flows -Settling Velocity of Floc in Turbulent Flows(2)-, Transactions of the Japanese Society of Irrigation, Drainage and Reclamation Engineering, 201, pp.13-20, 1999.6.
221. Kazuaki HIRAMATSU, Shiomi SHIKASHO, Ken MORI and Masayoshi HARADA: Retardation of Settling Velocity in Sinusoidally Oscillating Flows -Settling Velocity of Floc in Turbulent Flows(1)-, Transactions of the Japanese Society of Irrigation, Drainage and Reclamation Engineering, 200, pp.15-23, 1999.4.
222. Kazuaki HIRAMATSU, Shiomi SHIKASHO and Ken MORI: Short-Term Prediction of Water-Stages in a Tidal River using Feedback Artificial Neurtal network Model, Applied Hydrology, 11, pp.37-45, 1998.10.
223. Kazuaki HIRAMATSU, Shiomi SHIKASHO and Ken MORI, The Use of Genetic Algorithm and Artificial Neural Network for the Short-Term Prediction of Water-Stages in a Tidal River, Proceedings of the 11th Congress of Asia and Pacific Division of the International Association for Hydraulic Research, pp.587-595, 1998.09.
224. Masayoshi HARADA, Kazuaki HIRAMATSU, Shiomi SHIKASHO and Ken MORI, Measuring Method of Suspension Concentration in Open Channel Flow using Image Processing, Proceedings of the 11th Congress of Asia and Pacific Division of the International Association for Hydraulic Research, pp.607-616, 1998.08.
225. Nguyen Do Thuy, Masayoshi Harada, Kazuaki Hiramatsu, Shinji FUKUDA, Application of a simple genetic algorithm for the calibration of aquatic ecosystem model of an agricultural pond, Paddy and Water Environment, DOI:10.1007/s10333-012-0353-z, 12, 1, 1-15.
226. Trieu Anh Ngoc, Kazuaki Hiramatsu, Masayoshi Harada, Optimizing the rule curves of multi-use reservoir operation using a genetic algorithm with a penalty strategy, Paddy and Water Environment, DOI 10.1007/s10333-013-0366-2, 12, 1, 125-137.