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Research Topics

Study on Utilization of Satellite-based Topographical Data for Flood Risk Assessment

Developing countries often lack accurate topographic data necessary for water-related disaster risk assessment, and it is hoped that satellite-based topographic data will help those countries overcome this disadvantage. In this study, we will first test SRTM3 of NASA and ALOS of JAXA for reproducibility and then develop a topographic data processing method for each type of the data products to be used for inundation simulation. We will also develop a method for water-related disaster risk assessment which can use satellite topographic data.

Case study on comprehensive flood risk management in developing countries (Priority Project Research)

This case study project will develop methodologies specifically for developing countries to evaluate the effectiveness of various risk reduction alternatives, including the introduction of flood warning systems and flood hazard maps, and propose an effective flood risk reduction portfolio for a specific study area.

Publication of large flood reports (General Research)

Making use of a worldwide network of local experts, for example, through the IFI framework, policy effective information after major flood events is collected and analyzed, which will be published as “Large Flood Reports (tentative name)”.

World Water Assessment Program (WWAP)

The need for continuous monitoring and assessing the situation of the freshwater worldwide has gradually evolved as a result of a number of major conferences and fora (see: Water Milestones 1972-2003: from Stockholm to Kyoto). To ensure a continuous collective UN system-wide assessment process, the World Water Assessment Programme (WWAP) was launched in March 2000. The World Water Development Report (WWDR), the primary output of the WWAP, was first released in 2003 during the 3rd World Water Forum in Japan. WWDR includes thematic and methodological case study, water information and capacity building components.

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Flood Mitigation Policy in the Changjiang River

This research is a part of the research project -'Sustainable water policy scenarios for river basins with rapidly increasing population'-, started in October 2003. The project is one of the Core Research for Evolutional Science and Technology(CREST) research projects which are funded by Japan Science and Technology Agency(JST). We are executing the research in collaboration with the China Institute of Water Resources and Hydropower Research(IWHR).

The Flood plains and deltas of the middle to lower reach of the Changjiang River are prone to floods and are characterized by a high population density and extremely accumulated properties. Thus, one of the most important objectives of the Government of China is the construction of a flood control system in the area. Our research goal is to identify sustainable water policies for this area and to study the possibility of imparting the China's experience to other countries. To complete this research aim, we adopt a social science approach to analyze the process of establishing policy and its implementation process.

System Modeling Approaches for Assessment of Interaction between Social Changes and Water Cycle

This study is partially funded by the Core Research for Evolutional Science and Technology (CREST) Program under the Japan Science and Technology Agency (JST), "Research and Development of Hydrological System Modeling and Water Resources System." This study proposes system models for assessing effects of social changes on hydrological cycle in river watersheds, as well as water movement and balance especially among Asian countries, which are expected to be still dynamically developing with population and economical growths, industrial transfer and urbanization, while Japan is going to be in a stable developed stage. The models aim at quantitative assessment of interactions between meteorological-hydrological dynamics and social dynamism, and also of the availability and risk of freshwater resources in Asia. Also discussed are Japan's future water resources policies in connection with food and industrial policies, and strategic perspectives concerning how to contribute to the world.

As mentioned above, we intended to use the Chao Phraya River basin in Thailand as a case study. The Chao Phraya River Basin, the largest basin in the Kingdom of Thailand, is located in the central and northern part of Thailand.

Development of a database for hydrological model evaluation

In order to propose an approach to the mitigation of damage by water-related disasters such as floods and rain storms, it is essential to develop databases which enable the integration and management of various data regarding meteoro-hydrology, damage by disasters, social economy and other. The databases should also be able to serve for effective data sharing and use. This research aims to establish such databases that will be available for researchers in general and to contribute to the mitigation of damage by water-related disasters by analyzing a wide range of data.

Research on the methodology of estimation on coefficient of discharge on the spot

A new law established in 2003 allows a coefficient of discharge obtained by a field test at the site to be used for inundation measures when the land for non-residential use and more than 1000m2 is developed for other commercial or industrial purposes. However, there is not a established methodology for measuring a coefficient. The purpose of this research is to propose such methodology by carrying out field tests at different sites such as a dry field, a play ground, a forestland and so forth.

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Research on promotion of local use of satellite-based rainfall information in sparsely gauged areas (Priority Project Research)

In this research, the team aims to develop and disseminate the Integrated Flood Analysis System (IFAS) using satellite-based rainfall information and globally available GIS data and improve their applicability to poorly gauged basins in developing countries in order to assist them to implement efficient and effective flood forecasting and warning systems.

Outline of the Integrated Flood analysis system (IFAS)
Outline of the Integrated Flood analysis system (IFAS)

Development of a basin scale water and material circulation model

In rivers and water bodies, nutrient concentration levels remain unchanged despite various efforts to decrease them. Although river administrators are currently developing master plans for water quality improvement, it still remains uncertain whether the goals of the plans are actually achievable or not because nutrient discharge mechanisms from different sources to water bodies have not been clarified, and also because no basin-based water-quality assessment model has been developed to make an integrated assessment of the contribution of each source and the effects of countermeasures. To develop effective water-quality improvement plans, it is essential to establish a technique to simulate the discharge of nutrients (e.g. nitrogen and phosphorous) from different sources. It is also necessary to develop a tool for an integrated assessment and analysis of the quantitative effects of changes in land use and agricultural management, as well as the interaction of those factors.

This research aims to develop a practical basin-scale integrated water/material cycle model by improving the WEP model which has been developed by PWRI. To this end, discharge and transport models for nitrogen and phosphorus need to be added to the WEP model by clearly establishing discharge mechanisms from different sources to water bodies. Also, by studying actual applications of material cycle models both in Japan and overseas, modeling guidelines for selecting effective information to formulate basin-based policies is made.

Development of technology to evaluate flood risk based on Radar raingage information

Radar precipitation data can be effectively used to support risk management for floods in medium and small river basins, which have been frequent in recent years. They can also contribute to the effective use of water resources through advanced low flow management of river systems, because the data is easily accessible nationwide to input precipitation distribution for any basin. However, the current use of radar precipitation data hardly meets its high potentiality due to lack of research on the specific procedures and effects of its advanced use. Under these circumstances, it is important to promote assistance in flood risk management through the development of tools for precipitation analysis and flood risk assessment which make full use of the existing radar precipitation data.

This research aims to develop a tool to assist the flood risk management in poorly gauged medium and small river basins. To this purpose, the research plans to develop technologies to analyze precipitation using radar precipitation data (e.g. DAD analysis), to improve observational reliability using additional information provided by the radar system of the Japan Meteorological Agency.

Improvement of reliability on discharge observation data by using new sensor technologies

In order to achieve accuracy and efficiency in discharge data collection - need to be improved to ensure data reliability. In reality, discharge observation has not gone through any fundamental change since the 1960s and still remains inefficient at both field and office work. It is urgent to ensure both accuracy and efficiency in discharge data collection through the introduction of innovative observational technologies and the reduction of labor and cost in the process of producing and checking HQ curves. This research aims to verify the accuracy of discharge data collected in actual rivers using ADCP and prepare draft guidelines for the application and operation of ADCP for practical use. Also, the research plans to improve the existing HQ system to produce and check HQ curves, which are critical to determine official discharge data. These improvements will help ensure accuracy in the determination of discharge data and, at the same time, reduce labor and cost. Ultimately, the research will contribute to the standardization of an advanced technology which provides highly reliable low flow and high water discharge data.

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Assessment of the impact of climate change on flood disaster risk and its reduction measures over the globe and specific vulnerable areas

There is widespread concern about increasing flood risk worldwide due to climate change. In this research, global flood risk projection will be conducted using distributed flood analysis technology and the output results of a super-high-resolution atmospheric model. (1)First, change in flood hazard will be analyzed based on climate change projections. Also, flood vulnerability will be analyzed based on social data. Analyzing those data together, a 10-40 km mesh global flood risk map will be produced to show flood risk change during the period between the present and the end of the 21st century. (2)For specified vulnerable areas, flood risk change will be analyzed in 1 km grid size. (3)In both cases, necessary countermeasure scenarios for adapting to increasing flood risk will be proposed and the cost of those countermeasures will also be proposed with considering benefit from floods.

Development of a basic system for flood warning based on information derived from artificial satellites

There is an immediate need for early flood forecasting/warning systems in developing countries to mitigate flood damage in poorly gauged river basins. In such basins, however, it is difficult to get access to necessary hydrological data at a right timing and thus to apply a flood runoff model, because of the inadequate number of hydrological stations and incomplete observational databases.

In this research, a user friendly flood analysis system which can use satellite-based rainfall information, which has been developed recently, in near real time will be jointly developed with the private sector. The system will be applied to river basins in developing countries for validation and improvement. Flood analysis models and input/output interface functions (including systems for flood forecasting/warning) will be added to the system as necessary.

Utilization of satellite derived topography data to flood risk assessment

With water-related disasters increasingly more frequent worldwide, disaster preparedness is regarded as ever more important to cope with such disasters. It is in this context that flood risk assessment is urgently needed. In developing countries where it is often difficult to implement structural measures for various reasons, it is considered effective to design non-structural measures, such as land use, based on results of flood risk assessments. It is not always possible, however, to conduct flood risk assessment in developing countries, because they often lack access to topographical data that are accurate enough to use in such assessment. Alternatively, the use of satellite-based topographical data has been proposed. However the accuracy of satellite-based topographical data need to be assessed as soon as possible to be applied in flood risk assessment.

The following are planned in this research: verification of topographical reproducibility of SRTM3 developed by NASA and ALOS data developed by JAXA; development of a procedure for topographical data processing to optimize flood risk simulations using each topographical data; and flood risk assessment based on both flood runoff and inundation simulations. Also, the research will work on the development of a manual for satellite-based data processing and educational materials to introduce the use of satellite-based topographical data.

Other Research Projects

  • Research on sustainable tsunami countermeasures in developing countries (Priority Project Research)
  • Research on flood preparedness indices for local communities
  • Development of a method for practical use of satellite-based topographic data in water-related disaster risk management (Priority Project Research)
  • Development of a basin-scale water-/material-cycle model (Priority Project Research)
  • Development of systems for unmanned automatic river discharge measurement and methods for improving the reliability (Strategic Research)

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