No abstract

<p>Due to climate change, the scale of flood damage by localized torrential rains in urban areas is on an increase. Meanwhile, the existing flood runoff analysis methods do not consider buildings in urban areas, resulting in an overestimation of the degree of flood damage. Therefore, this study presents a method to consider buildings when applying XP-SWMM for flood analysis in downtown areas where buildings are concentrated, in order to accurately simulate the flood spread pattern around the building. To propose an optimal method which considers buildings, water depth, maximum flooded area, and the flow pattern around the building were compared according to whether or not the building was applied. As a result of the study, the average flooded area was 172,900㎡ when the building was set as an inactive area, which was 64% of the average flooded area (271,000㎡) when the building was not considered. The average water depth was 0.32m when buildings were considered, which was 1.78 times deeper than the average water depth (0.15m) when buildings were considered. This is the reflection of the blocking effect of the building in the model analysis, resulting in a significant reduction of the flooded area. In addition, since the flood simulation considered the flow rate of the same volume, flow velocity and average submerged depth relatively increased. This study is expected to contribute to the establishment of optimal downtown flood measures, by presenting a method for accurate flood analysis using the XP-SWMM model considering the influence of buildings in urban areas. For further improvement in the accuracy of flood analysis, it would be necessary to develop flood simulation methods suitable for different basins with flood records.</p> <p> </p> <p>This research was support by a (2022-MOIS63-002) of Cooperative Research Method and Safety Management Technology in National Disaster funded by Ministry of Interior and Safety(MOIS, Korea).</p>

<p>In recent years, the frequency and intensity of localized torrential rains in Korea have increased due to climate change, thereby increasing human and property damage through frequent urban flooding. Research on urban flood forecasting is mainly focused on numerical modeling and rainfall-based flood prediction, but the analysis technology of quantitative flood measurement data is lacking. In addition to flood mapping and verification of flood prediction results, it is necessary to develop urban flood management technologies using sensor-based quantitative flood depth measurements. The existing flood sensors have different management regulations depending on the development entities, and there are no set standard or basic performance standards, causing inefficiency in their budget and maintenance. Therefore, in order to improve the efficiency and prevent trial and error, this study proposes the performance standards and installation methods as guidelines, necessary for the installation and operation of flood sensors. To this end, firstly, domestic and foreign cases for urban flood sensors were reviewed for their installation procedures, installation location selection, measurement intervals, inspection and management plans, etc. The table of contents of the guidelines was derived through case analysis, consisting of a standard model installation plan that describes the detailed composition and operation principle of flood sensors, sensor installation plans for each measurement point such as the surface and sub-surface, on-site installation procedures, and instructions on a test run. These guidelines are expected to be followed to strengthen a proactive urban flood response system by effectively operating flood sensors.</p> <p> </p> <p>Acknowledgment: This research was support by a (2022-MOIS63-002) of Cooperative Research Method and Safety Management Technology in National Disaster funded by Ministry of Interior and Safety(MOIS, Korea).</p>

<p>Localized torrential rain, which has recently increased in frequency due to abnormal climate, accelerates erosion in the river basin and increases sediment transport into the river. The movement of inflowed sediment is one of the most important factors in the development and management of water resources.</p> <p>Among the mechanisms of sediment transport in rivers, bedload has limitations in direct measurement due to the risk it poses and inaccuracy in the existing measurement methods. Measurement equipment based on new concepts is continuously being developed to overcome these limitations. A representative equipment is a pipe hydrophone, which indirectly measures the bedload discharge by collecting and analyzing acoustic data when soil collides with a metal tube with a built-in microphone.</p> <p>To estimate the bedload discharge, this study acquired data through indoor experiment and applied them to the learning process of the Convolutional Neural Networks(CNN). First, an indoor hydraulic experiment device was built with a pipe hydrophone installed at the bottom of the water outlet of the indoor waterway. Then, a system for analyzing and displaying graphs for the impact sound of bedload, and data acquisition storage programs therein, was established. Finally, learning for bedload discharge estimation was conducted using CNN, and the accuracy of the estimation was reviewed.</p> <p>As a result, the F1-score for the accuracy of bedload discharge estimation was 61%, and the accuracy was higher when bedload discharge was 3kg and 10kg, compared to other weight ranges. Considering that the accuracy of 61% is an insufficient level to completely trust the estimated result, more efficient measurement would be possible by combining this method with the previously developed measurement methods in a complementary manner. In future studies, additional experimental data under various conditions will be secured and applied, to increase the accuracy of bedload discharge estimation.</p> <p> </p> <p>"This research was supported by Basic Science Research Program through the National Research Foundation of Korea(NRF) funded by the Ministry of Education(C20017370001)"</p>