The use of Flood Risk Maps in Disaster Risk Assessment (DRA): Urban case of Luján (Argentina)
Floods have become the natural disaster most extended around the world from 19941. Risk maps are non-structural measures (Pereyra, 2004) that represent fundamental mechanisms among activities related to disaster prevention. Luján (Argentina) has been impacted many times for different floods leaving a big amount of economical damage, evacuees and even people dead. The general objective of the thesis is related to contribute to Disaster Risk Assessment (DRA) through the development cartography of flood zones on urban areas considering three risk components: hazard, exposure and social vulnerability. The hazard is related to a potential danger that has natural phenomenon, potentially inherent to the event itself. Exposure is associated with the distribution of things that could be affected, like people and goods (González et al, 1998: 2; Villagrán De León 2001). Finally, social vulnerability is linked to socio-economical population conditions and the possibility of these being affected. The study of risk involves bibliographical research, the use of different GIS software's, compilation of data from diverse public or private institutions, queries and interviews to skate-holders and the community. Expected results of project are related to minimize the number of people affected by the floods; reduce economic losses, mainly related to infrastructure; improve the knowledge of social vulnerability situation in both cities, help to develop new skills for stakeholders working with cartography and Disaster Risk Management.
Keywords: Disaster Risk Assessment; cartography; floods; hazard; vulnerability; exposure
Responses of suspended sediment yield to precipitation, topography and soil conservation in the Yellow River Basin, China
Soil erosion has long been a serious problem in China’s Yellow River Basin. To mitigate this situation, large-scale soil conservation measures have been put into practice since 1970s. Since these soil conservation measures could inevitably lead a regime shift of sediment transport, new hydrologic regularities remain to be reinvestigated now. Therefore, this research aims to reanalyze the spatial variation of suspended sediment yield in terms of topographic, climatic, and possible anthropogenic factors in the yellow River Basin. By far, 2 main hydrologic regularities have been identified. 1) water discharge overall tends to increase with watershed area, but a less rapid trend can be identified in some big watershed; 2) suspended sediment concentration firstly tends to increase with watershed area, and then begins to decrease after the watershed area reaching a certain value. Future work will integrate available data to further explain hydrologic regularities identified.
Keywords: suspended sediment yield; topography; precipitation; soil conservation; Yellow River Basin
Research on Improved Mosaicking and Processing Algorithm of UAV Photographs for Natural and Environmental Study
UAV photographs have been widely used in the field of digital photogrammetry in environmental researches. However, the changing perspective of the camera in the procedure of obtaining oblique UAV images leads to severe geometric and radiometric distortions, which brings a huge challenge to mosaicking and processing of images. Due to these restrictions, traditional image mosaicking methods such as SIFT usually do not perform well. My research is going to propose a new algorithm to solve those problems for research on natural areas. I will analysis the result by comparing the efficiency and quality between the new algorithm and some existing image matching algorithms such as SIFT and ASIFT. Finally, I plan to apply the algorithm to a set of oblique UAV images of natural and environmental areas to test the robustness and scientifically evaluate the improved methodology.
Keywords: UAV; photogrammetry; SIFT; ASIFT
A Study on the Recession Rate of Sea Cliffs and the Development of Taluses in Byobugaura, Chiba Prefecture
Byobugaura is the sea cliff which runs from east to west for about 10 km in Chiba Prefecture. The highest cliff is about 60 m, and now there are break waters in front of the cliffs. The break waters were built from around 1960 to 2010 to prevent erosion and recession of the cliffs by waves. After building the water breaks, the sediments at the base of cliffs are not removed by waves, so taluses have been developing. So far there is no quantitative and high definition research of terrain in this area. Thus, the purpose of this research is to calculate the recession rate of sea cliffs in all area of Byobugaura, to analyze the relationship between the talus scale and formative time, and to analyze the terrain change process by UAV-SfM technique.
Keywords: Byobugaura; erosion; UAV-SfM
Analyzing the Human Impact on Shoreline Changes of the Mekong Delta
As the world’s third largest delta and most important biodiversity hotspot, the Mekong delta provides both ecological and food security for its inhabitants. However, because of climate changes and human activities, coastal region of Mekong delta has become one of the most dynamic regions with the highest erosion and accretion rate in the world. Tra Vinh is one of the provinces having serious shoreline landslide of the Mekong delta and the increasing complication of the erosion which concentrates on the shoreline areas. Therefore, analyzing and forecasting the trend of the shoreline changes in Tra Vinh province in particular is an urgent target. This study aims to improve our knowledge of the recent evolution of the Mekong delta and to link the potential impacts of human activities and other factors. GIS techniques will be used to compile the remote-sensing data for analyzing shoreline changes. Google Earth Engine (GEE) with Landsat data and Digital Shoreline Analysis System will be used to defined the shoreline and calculate shoreline-changes.
Keywords: Shoreline changes, Mekong Delta, GIS, Google Earth Engine