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Diploma and Master Theses (authored and supervised):

K. Kogure:
"Human impacts on river water quality - comparative research in the catchment areas of the Tone River and the Mur River";
Supervisor: M. Zessner; Institut für Wassergüte, Ressourcenmanagement und Abfallwirtschaft, Department of Environment Systems, Graduate School of Frontier Sciences, The University of Tokyo, 2013; final examination: 03-2013.



English abstract:
Human activities in river basin affect river water quality discharges into river with pollutant after we use water. The more people live in urban areas river water quality can become worse because of the inverse of the release of waste water. However, development of public sewer system with waste water treatment has enabled to improve river water quality. The main objective of this research is to reveal sources and pathways of pollutants put into river water and to find out effect of land use in the catchment area. By detecting pollutants source, pathway, and contribution of land use, we may know more influential factor of human activities. We can take proper measure to maintain ideal river environment by detecting factor and target. It is also expected to consider proper river basin management.
In this study, material flow analysis was done at first and secondary nutrient emissionmodeling by MONERIS was conducted. In order to clarify the land use contribution and climate condition, comparison of Japanese and European river basin area has been made. Content of this paper is MFA, MONERIS calculation, comparison of the Tone River Basin and the Mur River Basin, and possible proposal for river basin management.
Material Flow Analysis (MFA) was conducted for water cycle in the both river basin area. Nutrients sources and pathways were drawn by material flow chart. River water is the main focus of this study as the river water quality reflects nutrient emission into surface water from each factor in the basin. Data for area specific chart was obtained from statistical information, official reports, other information sources and results of calculation with MONERIS.
The model MONERIS (MOdelling Nutrient Emissions in RIver Systems; Behrendt et al., 2000) was applied to estimate the nutrient emissions in the Danube river basin by point sources and various diffuse pathways. The model is based on data of river flow and water quality as well as a geographical information system (GIS).Data collection and modelling for the Mur River Basin was already carried out by the Institute of Water Quality, Resources and Waste Management at the Vienna University of Technology. This research includes data collection, modelling with MONERIS for the Tone River Basin, and comparative analysis for these two river basins.
As MONERIS is GIS based numerical calculation system, GIS data were collected from various public agency or administrative websites. Other data can be obtained as published statistics and statistical data can be obtained from administrative agency of ministries. The sub catchment should have monitoring point for water quality and flow
data at the end of the area. The Tone River Basin was divided into six tributaries and five sub catchments from main channel. Monitoring data were obtained from 16 monitoring points along the river. Collected data sets were handled and analyzed to apply to MONERIS.
The soil surface balance calculates the difference between the total quantity of nutrient input entering the soil and quantity of nutrient output leaving the soil annually. By agricultural statistical data and specific N content formulas of harvests, animal products and excrement, N surplus can be calculated
In order to describe specific water cycle in the river basin area, water amount was subdivided to each land use category. Water cycle for the Mur River and for the Tone River Basin was described. In the Mur River basin, input water mainly passes through natural covered area and arable land. Irrigation is not done also in this area due to enough precipitation. In the Tone River Basin, they rely on highly in surface water especially for agricultural water supply. Urban area is 9 % and this may affect water cycle as evapotranspiration and ground water. As 37 % of the basin is agricultural area, effect of water use and transport related in the area was observed.
Numerical calculation for nutrient emission was carried out with MONERIS. The estimation of the nutrient emissions was carried out for 11 different sub catchment areas covering the Tone river basin for the time period 2000 to 2006.
TN emissions into the Tone river basin were about 51.23 kt/y N. The dominant pathway was input via groundwater with 67 %. The ratio of point sources in nitrogen emissions amounts to about 5 %, and the share of input vie surface runoff was also about 5%. TN emission via ground water was dominant for all sub catchments and urban area was also important emission pathway, and urban runoff was following.
Effect of human activities is observed in urban structure and agricultural activity. Water supply and sewer system construct urban water cycle via pipeline structure. Excess of evapotranspiration in agricultural area in the Tone River Basin is also influential the whole water cycle in the basin.
As share of arable land is 37% and agricultural products are delivered from this area, it is thought that N emission originated from agricultural activity is main nutrient pollution source. Assumption in case of 10% N surplus was simulated with MONERIS. TN emission was 99% identical the results of the Tone River Basin. Even though short term N surplus reduction does not show drastic impact on N emission, it is of importance to reduce excess of fertilization and encourage effective agricultural activity.
Population rate of waste water treatment is 67 % in the total catchment area. Assumption in case of 100% WWT was simulated with MONERIS. The result suggests that connection to public sewer system with WWTP is effective and potential measure for river basin management.
TN emission in the Tone River Basin is higher than it in the Mur River Basin. The Tone River Basin has higher emission stress in a certain area. Emission per capita is almost same level for both basin areas. Even though the personal pollution stresses same as European basin area, the basin has the large number of population and activities to support daily life of huge population. Higher emission stress is charged in the Tone River Basin because of its large population.
Agricultural activity and urban structure have great impacts on N emission and also on the river water quality. Possible remedy for river pollution from is construction of sewer system with waste water treatment plant. Agricultural activity is potential betterment factor.

Keywords:
River basin management, water cycle, nutrient emission, MFA, MONERIS

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