Towards a Seasonal Spatial Distribution of Simultaneous Severe Floods
Abstract
Floods are considered as one of the most harmful natural hazards. Despite new advances in flood management, these phenomena cause substantial economic and social losses every year. Managing the floods that occur simultaneously in different regions is one of the challenging issues for researchers and authorities. According to the intensity, the amount of rainfall and its association with snowmelt, floods may have different types. For this reason, the areas with simultaneous floods can also depend on the specific season in which floods occur. Identifying these concurrent flooded regions can help the assessment of flood risks and the adaptation of subsequent defenses. In this study, the daily discharge time series for 55 years from 1961 to 2015 in 46 measurement gauges in the Neckar catchment in Germany is split into cold and wet seasons, including the summer months. Then, the dissimilarity matrix of identified extreme floods is employed in hierarchical clustering. Finally, clustering evaluation is done based on the variation of information method to determine the best clustering map. The results indicate three major clusters, which illustrate different groups for flood occurrences in distinct seasons. In the cold season, the upper Neckar with a high concentration of small subcatchments and high elevation is vividly clustered into two parts. All subcatchments leading to the Neckar River in this area plus Würm River are in a cluster in the west. Moreover, all tributaries of the Fils River in the east are in a separate cluster. The Lower Neckar region is grouped in a different cluster. These clusters follow the topography of the studied region explicitly. Wet season clusters show partly not flow-connected areas in a cluster. Thus, the whole western region of the catchment with two distinct tributaries and some independent catchments are in one cluster. Although the second cluster is fairly the same as the eastern upper Neckar cluster in the cold season, a not flow-linked area is in this cluster. Therefore, the clustering map of the wet season is mainly related to the spatially rainfall distribution and elevation.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2021
- Bibcode:
- 2021AGUFMNH15D0464M