Browsing by Autor "Shuichi KURE"

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APPLICATION OF A TWO DIMENSIONAL FLOOD MODEL FOR DEFINING EVACUATION ZONES FOR CATTLE IN THE BOLIVIAN AMAZONIA
(2015) V. Moya Quiroga; Shuichi KURE; Keiko Udo; Akira Mano
River floods are natural disasters that affect millions of people every year. In addition, vast areas of floodplains used for cattle farming are inundated annually, and animals often drown. Depending on the floodplain characteristics, the floods can last for several days or even months. Even if the water depth is not sufficient to drown cattle, the long exposure to flood water may cause diseases. Thus, it is important to define safe zones and to identify safe routes for cattle to reach such zones. This study proposes flood evacuation zones for cattle in the Llanuras de Mojos (in the Bolivian Amazonia), based on the results of a two-dimensional flood simulation using a flood inundation model. Flood simulations provided the daily variation in the extent and depth of flooding. These results enabled flood hazard zones to be defined for cattle on different days. It was found that the left margin of the Mamore River was the most hazardous zone, with flood depths that were likely to drown cattle. The best evacuation route was identified as the right bank of the Mamore River located on the northern edge of the city of Trinidad.
Changes in the Hydrologic Design Discharges due to Climate Change: Bolivian Amazonia
(2016) V. Moya Quiroga; Shuichi KURE; Keiko Udo; Akira Mano
The Mamore river is the most important Bolivian river and one of the most important tributaries of the Amazon river. Engineers design flood control structures and water use plans considering hydrologic design discharges. Climate change will change the hydrological conditions. Thus, current hydrologic design discharges may not be valid for future conditions. Unfortunately, there are no studies about future streamflow conditions and future design discharges; hence, there is uncertainty about the future performance of flood control structures and water use plans. The present study analyzes the changes in the hydrological design discharges of the Mamore river due to climate change. The semidistributed hydrological model Supertank was used to simulate the streamflow of the Mamore considering current and future climatological conditions. Future conditions were simulated using downscaled projections of the WRF model based on projections from different general circulation models. Results show that future peak design discharges will increase between 11% and 16%. Future low flows show higher uncertainty. According to some projections future low flow will decrease 25%, while according to other projections future low flows will increase 30%.
Estimation of Glacier Melt Water Contribution for Human Consumption in the Royal Andes Considering Temperature Measurement Errors
(Scientific Research Publishing, 2014) V. Moya Quiroga; A. Mano; Yoshihiro ASAOKA; Keiko Udo; Shuichi KURE; J. Mendoza
Glaciers from the West side of the Royal Andes are an important source of fresh water for some of the most important Bolivian cities like El Alto. Temperature is an important datum for hydrological modelling and for glacier melt estimation. All temperature measurement devices have some degree of uncertainty due to systematic errors; thus, any temperature measurement has some errors. It is important to estimate the influence of such errors on the results from hydrological models and the estimation of melt water. The present study estimates the melt water contribution from the glaciers Tuni and Huayna West as a source of water supply for human consumption of El Alto considering the errors from temperature measurements. The hydrologic response of the basins was simulated with a hydrologic model. The glacier melt contribution was estimated as the difference between the discharge from the current scenario (with glaciers) and the discharge from a scenario without glaciers. Several volumes of melt water were estimated considering the temperature measurement and its possible errors. The uncertainty of such melt water volume was addressed by performing a Monte Carlo analysis of the possible melt water. The melt water contribution from glacier Tuni and Huayna West during the hydrologic year 2011-2012 was between 1.37 × 106 m3 and 1.72 × 106 m3. Such water volume is enough to meet the yearly water demand of between 6.81% and 8.55% of El Alto.
Probabilistic estimation of glacier volume and glacier bed topography: the Andean glacier Huayna West
(2013) V. Moya Quiroga; A. Mano; Yoshihiro ASAOKA; Keiko Udo; Shuichi KURE; J. Mendoza
Abstract. Glacier retreat will increase sea level and decrease fresh water availability. Glacier retreat will also induce morphologic and hydrologic changes due to the formation of glacial lakes. Hence, it is important not only to estimate glacier volume, but also to understand the spatial distribution of ice thickness. There are several approaches for estimating glacier volume and glacier thickness. However, it is not possible to select an optimal approach that works for all locations. It is important to analyse the relation between the different glacier volume estimations and to provide confidence intervals of a given solution. The present study presents a probabilistic approach for estimating glacier volume and its confidence interval. Glacier volume of the Andean glacier Huayna West was estimated according to different scaling relations. Besides, glacier volume and glacier thickness were estimated assuming plastic behaviour. The present study also analysed the influence of considering a variable glacier density due to ice firn densification. It was found that the different estimations are described by a lognormal probability distribution. Considering a confidence level of 90%, the estimated glacier volume is 0.0275 km3 ± 0.0052 km3. Considering a confidence level of 90%, the estimated glacier thickness is 24.98 m with a confidence of ±4.67 m. The mean basal shear stress considering plastic behaviour is 82.5 kPa. The reconstruction of glacier bed topography showed the future formation of a glacier lake with a maximum depth of 32 m.