In order to improve short-term (less than an hour) forecasting, a cell-tracking algorithm was applied to strong precipitation areas. The surface rainfall data derived from an X-band multi-parameter radar were used as initial data, and Algorithm for the Identification and Tracking Convective Cells (AITCC) was used to estimate the movement vectors of strong precipitation areas. The results showed that the cell-tracking system improved the forecast of hourly rainfall compared to traditional pattern matching extrapolation, especially for quasi-stationary rainfall systems such as back-building storms.

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We developed the advanced nowcast method focusing on the difference of precipitation propagation between the horizontal scales. We separate the precipitation distribution observed by X-band MP radars into small-scale and large-scale component using the wavelet transform. Prediction of each component is made by applying the conventional nowcast method. We get prediction of precipitation distribution by adding the predicted small and large components. Developed method is better at prediction of the propagation of small-scale component than traditional method. As a result, the prediction error decreased.

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A lot of regional heavy rains that are called a Guerrilla-heavy rain are reported in our country starting with the disaster in the Hyogo Prefecture Toga river on July, 2008. In recent years, such disasters become a problem. As part of measures of such disasters, we research about dangerous prospect of baby cells of Guerrilla-heavy rain by analysis in terms of vorticity that uses Doppler velocity. we define two vortexes with different size, and evaluate a relationship qualitatively between rainfall and the existence of vortex.

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 Hii river is located in the southern part of Lake Shinji where there is significant snowfall in the winter.
Therefore, it is important that we estimate how much and when runoff from snowmelt is being produced in this area.
 In this sutudy, we have developed models for the estimation of distibuted snow water equivalent and snowmelt. The objective of the present work was to develop and compare simple snowmelt model formulations using data from Hii river basin.

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For better estimation of snow water equivalents for a dam basin in cold snowy regions, the relationship between snow depth distribution and topography (elevation, slope, curvature and slope aspect) in the forest was investigated using a high-resolution DEM created from an airborne laser scanning conducted on a certain day in the snowy period and another one in the snow-free period. Based on the results, a snow water equivalent estimation model was developed. The model was used to estimate snow water equivalents in six dams, and resulted in estimates with a higher level of accuracy than those based on snow surveys.

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This study investigated annual and monthly glacier mass balances Tuni and Huayna Potosi glaciers in Bolivian Andes by hydrological method. Results suggest that hydrological method is sensitive to meteorological and hydrological data but reliable measurements enable it to carry out frequent and intensive analysis that clarify temporal and spatial glacier mass balances. Sublimation, evaporation, and evapotranspiration were also included and proved to be an important element in the water balance. 

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  Groundwater observation wells have been bored in 42 sites in Tokyo Metropolis by Tokyo Metropolitan Government. Large fluctuations of confined groundwater levels in Tokyo were observed following the 2011 Off the Pacific Coast of Tohoku Earthquake. In this study, the fluctuations of confined groundwater level caused by the earthquake were investigated. As for the results, seven fluctuation patterns were identified for the confined groundwater levels. The increase after short drawdown was a major pattern for the confined groundwater levels. The causes of those patterns were additionally outlined in this study.

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Water resources are not sufficiently available in arid areas, moreover, its distribution in space and time has been ever challenging to water managers. Groundwater availability shows mainly spatial variability in terms of quality and quantity due to the hydrogeologic setting boundary conditions and aquifer properties.
Based on the highlights mentioned above, conjunctive use of surface water and groundwater considering surface and subsurface environments and an integrated management of the limited water resources are most critical for the development of the Nile Delta aquifer. Simulated water head was presented with current and future scenario of flow rate change under steady stat conditions

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To reveal spatiotemporal structure of groundwater-river interaction, a combined approach of isotopic tracer and numerical simulation was applied to the Nasu alluvial fan. Results showed that river-recharged groundwater dominated in areas up to 3 km from river channel in the fan apex, while it became narrower in the fan rim zone. These areas shrank from wet season to dry season. The estimated contribution ratios for different recharge sources by the present approach were in very good agreement with those estimated by End Member Mixing Analysis, suggesting significant reliability of the estimates.

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Understanding the interactions between surface water and groundwater is critical for effective water resource management. This study is the first attempt to determine the spatio-temporal patterns of the interactions between the Red River and the PCA in Hanoi, Vietnam. In this study, an integrated surface-groundwater model was developed by coupling two commercial modeling packages: MIKE 11 and MODFLOW. The results revealed that there was very high correlation between the river water levels and PCA groundwater levels. The correlation was found decreasing not only with the distance from the river but also from the upstream to downstream along the river.

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This paper shows that the flow rate of fresh groundwater or its recharge rate is an important key to positioning of the saltwater wedge in an aquifer through the theoretical approach. To grasp growing/shrinking triggers of saltwater wedge, a clear interface between fresh and salt water without a mixture zone is assumed. The relationship between a horizontal distance from the seashore front and a vertical one from the sea-surface to the interface can be derived. This equation derived herein can prove that the flow rate of fresh groundwater or the corresponding recharge rate strongly affects the position of the saltwater wedge.

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Failure of the traffic occurs often after the heavy rain due to the spewing groundwater from the pavement in reclaimed ground over the small valleys on Tama Hills.In this paper, for study of spring water drainage by the Ground water level observation for several years and describes the hydrological characteristics

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Land surface hydrological processes (soil moisture, permafrost and snow cover) over the Tibetan Plateau affect the Asian Summer Monsoon variability. Particularly, permafrost degradation leads to substantial changes in hydrologic characteristics under continued global warming. Therefore, interdecadal changes in seasonal freezing and thawing depth in permafrost play important roles on heat and water cycle in the Tibetan Plateau. In this paper, the characteristics of soil moisture and temperature change are firstly revealed based on the observed data in the Tibetan Plateau. Secondary, the long term simulation is carried out by using CLM3.5 (Community Land Model Version 3.5). The observed data indicates that soil moisture in deeper soil has been increasing in the South observation site, on the other hand, has been decreasing in the north part. The offline CLM3.5 simulated the vertical profile of soil moisture and temperature in the Tibetan Plateau. The characteristic of CLM3.5 is to overestimate the soil moisture compared with the observed data. It is found that the estimated soil moisture and temperature does not agree with the observed one. It is because that the initial condition and input data are not evaluated based on the observed data. Therefore, to simulate the hydrological process precisely, we should improve the initial condition and input data by analyzing the observed data.

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Sprinkling management is indispensable for lawn-planting in greening urban areas. In this study, numerical experiments are performed using 1-D soil-plant-atmosphere continuum model in order to quantify the effect of sprinkling on the temperature distribution. Reproducibility of 1-D soil-plant-atmosphere continuum model is attempted using micro-meteorological observations. The observations were carried out in an urban green park and on a thin rooftop greening. The model parameters are set by measure and literature value. The calculated results agree well with the observed values except high soil moisture retention condition.

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This study try to represent the redistribution of soil water within a soil column numerically. It is shown that both suspended water and surface soil moisture can be represented by using emperical formulae induced from numerical solutions of Richards eqution.

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We developed a new hydrological model by integrating sediment transport process to runoff model called Hydro-BEAM.
The model can analyze transport of cesium attached to sediment.
We applied the model to The Abukuma River.

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The goal of this study is preliminarily to assess the application of the high-resolution ensemble NWP model data for the purpose of flood forecasting using distributed hydrologic model. In dealing with the ensemble flood forecasting, we used the ensemble rainfall information of high-resolution NWP model and carried out forecasting verification to assess the quality of forecast in comparison with observed radar rainfall. Furthermore, we assess the changeable aspects of flood forecasting using ensemble rainfall information. 

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In this paper, we implement a Kalman filter on Urban Storage Function (USF) model which incorporates urban runoff process. The model parameters are updated with 1-minute river discharge data by the Kalman filter. The model is applied to the upper river catchment of the Kanda River in Tokyo. The results show that USF model using the Kalman filter forecasted the amount of river discharge accurately.

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In this study, the compromise programming of a multi-objective optimization method is applied to parameter estimation of the Tank Model to simulate both high and low flows with acceptable accuracy. Root Mean Square Error (RMSE) that emphasizes the errors at high flow and Root Mean Square of Relative Error (RR) that emphasizes the errors at low flow are used as objective functions. A compromise solution of the Tank Model parameter set is estimated by the compromise programming and Pareto solutions are also estimated by the weighting method using hydrological data of three dam basins.

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The weakening of vertical mixing in Lake Biwa is recently observed and may have the reverse impact on water quality. It is necessary to understand the mechanism of vertical mixing. In this study, three-dimension water quality model in the Lake Biwa was developed. This model includes nine components, such as, phytoplankton and dissolved oxygen. This model was calculated for 1 year of 2007.The calculated values showed the good agreement with the observed value, especially in seasonal variation. The result of the future forecast from 2050 to 2054 implies the effect of global warming.

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The study of specific nitrogen load for the upstream region in many basins, where are measured on the nitrogen of river water every month, is carried out by using the database of water information system. In the spring snowmelt period, the fresh snow changes to granular snow, and the ion of snowpack flows out, and its ion concentration gradually lowers. Therefore, the nitrogen concentration of large rivers with high mountains lowers by abundant and clean snowmelt water of granular snowpack. By returning this, the nitrogen concentration of the river in the no snowfall basin is high.

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Export of suspended solids means soil loss and export of nutrients absorbed, so it is important to estimate SS loads accurately. SS concentration demonstrates strong nonlinear relationship to flow rate in general. SALT sampling method enables the balanced sampling with appropriate proportion between high- and low-flow regime because that it samples data according to the magnitude of loading. In this paper, effectiveness of SALT sampling method in estimating SS load from a small forested catchment was evaluated. Improvement in load estimation with SALT sampling was also demonstrated.

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In recent years the eutrophication of the Lake Biwa and rivers has induced the serious environmental problems. The water quality model for the Yodo River Basin has been developed in order to solve these problems. In this study, the discharge from main five dams was estimated by arranging the dam water level in the flood period and in non-floods period. SS concentration in the dams was estimated by assuming the complete mixing. Consequently, the water quality model was improved to be able to predict the river water quality without the observed data in dams.

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In this study, we focus on probable maximum precipitation(PMP) for Japanese river basin, as following procedures.1.GPV data and Rader Amedas data are used for calculating precipitable water in several rainfall duration.2. Maximum values of atmospheric water vapour for storm maximization are estimated from maximum dewpoints by considering wind direction for heavy rainfall. 3.In this method, PMP is larger than precipitation by traditional  method because precipitable water accuracy is improved.4.Transposition method is studied from Typhoon characteristic ,such as Typhoon root, central pressure, wind speed.

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Return levels of daily rainfall at 21 observatories all over Japan were estimated by applying Peak-Over-Threshold (POT) theory, and POT estimates were compared with estimates by applying conventional extreme value theory to Annual Maximum Series (AMS). Threshold value required for POT method was standardized by using average and standard deviation of annual maximum daily rainfall, and the same standardized threshold was applied to daily rainfall data at each observatory. Results show that POT and AMS estimates were close for short return period for all observatories; however, significantly different for long return period for some observatories where extremely large rainfall was recorded.

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We used daily precipitation data at 51 obsevation stations and obtained the most appropriate probabily distribution. In addition to the GEV, Gumbel, log-normal, Pearson III distribution, we applied the Wakeby distribution, Kappa distribution and Levy distribution. As a result, we found that log-wakeby is most appropriate at a lot of observation stations.

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Recently, occurrences of localized heavy rainfall and the risk of the urban flooding are increase in urban area. Urban flood is occured rapidly after rainfall occurred. For these reasons, we developed the flow nomograph, which can be used quickly. The flow nomograph based on rainfall information is assembled and comprised by the relationship with flood discharge and level from rainfall scenarios. The application watershed is Cheonggye stream, Korea. As a result of assessment, more than 88% among 10 rainfall events were suitable. Furthermore, we will develop flow nomograph at Toga river and use the MP-X radar for leadtime of rainfall.

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   It is an objective of the study that the author research on a possible methods due to increase for waterpower generation, with reviewing for control manual in the Kusaki dam of multi-purpose. Namely, it is significant that to make decreasing an invalidated outflow discharge at flood outflow, and also to make increasing an effective outflow discharge that change into waterpower generation. As following, we had suggested new system that is said to be beforehand outflow methods in dam control, and simulated base on the hydrological data of Kusaki dam management during 15 years. Run-off analysis of heavy rain using tank model, a quantitative of an effective outflow discharge and waterpower generation was carried out.

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The evaluation of environmental impacts is often summarized in the form of an environmental impact assessment (EIA) study. The common practice of EIA in the Philippines is generally qualitative and lacks clear methodology in evaluating multi-criteria systems, thus, this study proposes the use of the rapid impact assessment matrix technique to systematically and quantitatively evaluate the impacts of structural flood mitigation measures (SFMM) in Metro Manila. Based on the results, the SFMM will likely bring both significant positive and significant negative changes. This study provides a clear view of the impacts associated with the implementation of SFMM projects. 

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We developed a diurnal rainfall pattern generator, and it was used to generate various patterns of heavy rainfall data. Here, 300 patterns of hyetograph were generated with present and future rainfall amounts, respectively. They were all input to a drainage model for impact assessment of climate change.As a result, in the future period, the risk of exceeding a Flood Level at lagoon was predicted to rise by nearly 15% from the present period. In addition, the duration of inundation of paddies was estimated to increase. Countermeasures such as revision of drainage planning may be necessary.

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A massive flood, the maximum ever recorded in Thailand, struck the Chao Phraya River in 2011. We had a questionnaire investigation for citizen in Chao Phraya River basin from 4th to 9th in 2011 which consisted of two question types, first was the damage situation and disaster response, second was the civil understanding for the flood disaster. We got 142 subjects.  We show the relations between the damage situation and response, and the understanding for main cause of this flood and past floods in Thailand.

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Taking the catastrophic inundation in the Chao Phraya River basin, of which the flooding in the Bangkok Megalopolis was reported as big news, we analyzed functions of flood storage by paddies to lessen damage in urban areas. As a result, based on concrete figures of those functions, top-rated irrigation paddies, surrounded by roads and levees, played an important role for decreasing damage in Bangkok areas.

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The dry season rice cropping and its water demand is investigated at Bhumibol dam and Sirikit dam in Thailand. The increase of the cropping area in the dry season has been accomplished by improved irrigation efficiencies. It is necessary to investigate the change of cropping system, sustainable water demand of the dry season for water allocation.

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The 2011 massive flooding in Chao Phraya, Thailand prompted its government to revise its river management plan. H08 Model was one of the models chosen for this purpose due to its ability to incorporate reservoir operation in modeling. This study serves as base step of this purpose by calibrating four globally-determined parameters to suit the local conditions. The optimized parameter sets resulted to very good hydrograph fits in the daily, monthly and annual scales from 1981-2004 and 2010-2011. Nash-Sutcliffe coefficients at monthly and annual scales are 81% and 85%, respectively. Flood peaks corresponded well with that of the naturalized observed.

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Chao Phraya is the main river basin of Thailand. The most important of the river is supporting over 90% farm land and rice field of the land area; therefore, flood control and management of the Chao-Phraya river basin become an important issue for Thai water authorities. Thus, the mathematical models have been integrated to prepare flood information for an early flood warning system.This study purposes to provide the flood forecasting information for an early flood warning system. Finally, integrated model can estimate the accurate water level in the main channel.

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Meteorological conditions are revealed to change, which may have caused more flood disaster, greater typhoon and so on in terms of climate change. Therefore, strong wind pattern is also expected to change and to have an effect on water quality in Tokyo Bay.  This study aims to clarify the impact of meteorological change on the occurrence of strong south-west winds (KEw), which enhance rapid recovery from hypoxia by using MRI-AGCM3.1S, MRI-AGCM3.1H, MRI-AGCM3.1L, and eight models in CMIP3 outputs. As a result, it is suggested that recovery from hypoxia in the future does not occur more rapidly than the present.

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Water-related disasters are projected to increase under a future climate. In this study, a new method is developed to evaluate the occurrence and risk of innundation disasters in Japan. Firstly, the method is calibrated to reproduce inundation disasters occurred from 1993 to 2009. Secondly, the method is applied for future climate simulations by GCM20 and MIROC. In the period from 2080 to 2099, the number and risk of inundation disasters will become higher than those in the present climate. The risk increases substantially where extremely heavy precipitation occurs and the average risk is highly variable by simulations.

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Future changes in summertime precipitation amounts in the Japanese islands associated with the topography were investigated using regional climate projections from NHRCM, NIED-RAMS, and T-WRF. All the projections for a period of 2081-2100 show that future increases in the summertime precipitation amounts are remarkable in the south and west sides of the mountainous regions. Also, the large precipitation increases can be recognized not only in the highlands but also in the lowlands including urban areas. This indicates that the future global warming could increase rainfall-inundation potential in urban areas.

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This paper shows an impact estimation of climate change on rice production and water demand-supply balance in Japanese Basins. As importance of the climate change problem has become larger and larger, its impact evaluations are strongly desired for science. We developed a Japanese water resources model composed of five sub-modules. Simulated river discharge and yield with observed-based meteorological forcing were compared and validated with observed stream flow record at 20 primary river gauging stations and statistical yield data. Balances of demand and supply in Japanese all basins are evaluated with water stress index. 

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The results of bias-correction methods applied to monthly temperature and precipitation data which is simulated by multiple General Circulation Models (GCMs) are compared among GCM outputs in this study. The difference is so apparent that we should care about it when we apply a bias-correction method. There still remains left to not validate enough, we believe the fact explained in this study is useful to choose a bias-correction method for impact assessment.

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Change of water disaster risk under climate change should be understood quantitatively. Thus we executed off-line simulation by land surface model which includes anthropogenic water operation, and investigate how the risk would shift. In this presentation we are going to discuss risk of draught.  In this study, improved land surface model “HiGW-MAT”, which is integrated model of land surface model “MATSIRO” and anthropogenic operation module, and river routine model “TRIP” was used. HiGW-MAT can simulate such anthropogenic operation that crop growth, dam and pond operation, environmental flow and some kinds of water withdraw. As a input data for the model, we prepared new future forcing data made based on reanalysis data.  Results shows that river discharge would largely decrease in Europe, Middle East, North America, some part of South America and north part of central Siberia. On the other hand, in south part of Africa, south-eastern Asia, Australia and a part of south America, discharge would largely increase under climate change. Regarding draught risk, draught day would increase more than a hundred days in 20 year average in Middle East, America and Chile where average discharge would largely decrease. It means there is huge possibility of increase of draught risk in these regions.  Ratio of discharge change due to ON/OFF of anthropogenic operation module against discharge change caused by climate change is at most 10 percent, though in India those impact are relatively same. This research indicates that water withdraw in some region where discharge would decrease could result in further lower discharge, though reservoir operation and irrigation water supply could mitigate draught risk in other regions.

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Pattern scaling approach is a useful approach to investigate the impacts of global warming under a very wide range of emission scenarios We investigated the regional impacts of  aerosols emissions on precipitation in Representative Concentration Pathways to validate the pattern scaling approach. The emissions of anthropogenic aerosols per 1 K global mean SAT differ between emission scenarios in RCPs over the East Asia, the east parts of North America and the region around the Gulf of Guinea. Consequently, evaporation is significantly different between esmission scenarios. The differences in evaporation result in the differences in precipitation over these regions.

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Soil water at a taiga forest in eastern Siberia was simulated with a land-surface model and routine meteorological data set (BMDS ver. 5) from 1966 to 2008. The effect of soil initial condition was disappeared within 8 years. The simulated column soil water indicated variation with about ten year’s period; it corresponded with reconstructed soil moisture based on delta 13C of tree rings. The simulated soil water content in 2006 and 2007 was heist in the study period.

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It is important to project the impact of climate change on water resources, and to plan feasible adaptation measures. A number of reports have been published on this topic, but there are typical problems. First, most of the earlier works assessed water resources on annual basis. Second, most of the earlier works fixed various conditions at present except climate and population. Third, all earlier works used socio-economic and emission scenarios by Nakicenovic and Swart (2000; called SRES) and CMIP3 climate scenario. In this study, a new global water stress assessment is presented overcoming these problems using new IPCC scenarios.

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