TY - JOUR A1 - Samprogna Mohor, Guilherme A1 - Hudson, Paul A1 - Thieken, Annegret T1 - A comparison of factors driving flood losses in households affected by different flood types JF - Water resources research N2 - Flood loss data collection and modeling are not standardized, and previous work has indicated that losses from different flood types (e.g., riverine and groundwater) may follow different driving forces. However, different flood types may occur within a single flood event, which is known as a compound flood event. Therefore, we aimed to identify statistical similarities between loss-driving factors across flood types and test whether the corresponding losses should be modeled separately. In this study, we used empirical data from 4,418 respondents from four survey campaigns studying households in Germany that experienced flooding. These surveys sought to investigate several features of the impact process (hazard, socioeconomic, preparedness, and building characteristics, as well as flood type). While the level of most of these features differed across flood type subsamples (e.g., degree of preparedness), they did so in a nonregular pattern. A variable selection process indicates that besides hazard and building characteristics, information on property-level preparedness was also selected as a relevant predictor of the loss ratio. These variables represent information, which is rarely adopted in loss modeling. Models shall be refined with further data collection and other statistical methods. To save costs, data collection efforts should be steered toward the most relevant predictors to enhance data availability and increase the statistical power of results. Understanding that losses from different flood types are driven by different factors is a crucial step toward targeted data collection and model development and will finally clarify conditions that allow us to transfer loss models in space and time.
Key Points
Survey data of flood-affected households show different concurrent flood types, undermining the use of a single-flood-type loss model Thirteen variables addressing flood hazard, the building, and property level preparedness are significant predictors of the building loss ratio Flood type-specific models show varying significance across the predictor variables, indicating a hindrance to model transferability KW - Loss modeling KW - Riverine floods KW - Surface floods KW - Groundwater KW - Levee KW - breaches KW - Compound flood event Y1 - 2020 U6 - https://doi.org/10.1029/2019WR025943 SN - 0043-1397 SN - 1944-7973 VL - 56 IS - 4 PB - American Geophysical Union CY - Washington ER - TY - JOUR A1 - Kühn, Michael A1 - Altmannsberger, Charlotte A1 - Hens, Carmen T1 - Waiweras WarmwasserreservoirWelche Aussagekraft haben Modelle? JF - Grundwasser : Zeitschrift der Fachsektion Hydrogeologie in der Deutschen Gesellschaft für Geowissenschaften (FH-DGG) N2 - The warm water geothermal reservoir below the village of Waiwera in New Zealand has been known by the native Maori for centuries. Development by the European immigrants began in 1863. Until the year 1969, the warm water flowing from all drilled wells was artesian. Due to overproduction, water up to 50 A degrees C now needs to be pumped to surface. Further, between 1975 and 1976, all warm water seeps on the beach of Waiwera ran dry. Within the context of sustainable water management, hydrogeological models must be developed as part of a management plan. Approaches of varying complexity have been set-up and applied since the 1980s. However, none of the models directly provide all results required for optimal water management. Answers are given simply to parts of the questions, nonetheless improving resource management of the geothermal reservoir. KW - Groundwater KW - Geothermal water KW - Seawater intrusion KW - Simulation KW - Reservoir KW - Management Y1 - 2016 U6 - https://doi.org/10.1007/s00767-016-0323-2 SN - 1430-483X SN - 1432-1165 VL - 21 SP - 107 EP - 117 PB - Springer CY - Heidelberg ER - TY - JOUR A1 - Böttcher, Steven A1 - Merz, Christoph A1 - Lischeid, Gunnar A1 - Dannowski, Ralf T1 - Using Isomap to differentiate between anthropogenic and natural effects on groundwater dynamics in a complex geological setting JF - Journal of hydrology N2 - Due to increasing demands and competition for high quality groundwater resources in many parts of the world, there is an urgent need for efficient methods that shed light on the interplay between complex natural settings and anthropogenic impacts. Thus a new approach is introduced, that aims to identify and quantify the predominant processes or factors of influence that drive groundwater and lake water dynamics on a catchment scale. The approach involves a non-linear dimension reduction method called Isometric feature mapping (Isomap). This method is applied to time series of groundwater head and lake water level data from a complex geological setting in Northeastern Germany. Two factors explaining more than 95% of the observed spatial variations are identified: (1) the anthropogenic impact of a waterworks in the study area and (2) natural groundwater recharge with different degrees of dampening at the respective sites of observation. The approach enables a presumption-free assessment to be made of the existing geological conception in the catchment, leading to an extension of the conception. Previously unknown hydraulic connections between two aquifers are identified, and connections revealed between surface water bodies and groundwater. (C) 2014 Elsevier B.V. All rights reserved. KW - Groundwater KW - Lake KW - Interaction KW - Isometric feature mapping KW - Time series analysis Y1 - 2014 U6 - https://doi.org/10.1016/j.jhydrol.2014.09.048 SN - 0022-1694 SN - 1879-2707 VL - 519 SP - 1634 EP - 1641 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Balcke, Gerd U. A1 - Hahn, M. A1 - Oswald, Sascha T1 - Nitrogen as an indicator of mass transfer during in-situ gas sparging JF - Journal of contaminant hydrology N2 - Aiming at the stimulation of intrinsic microbial activity, pulses of pure oxygen or pressurized air were recurrently injected into groundwater polluted with chlorobenzene. To achieve well-controlled conditions and intensive sampling, a large, vertical underground tank was filled with the local unconfined sandy aquifer material. In the course of two individual gas injections, one using pure oxygen and one using pressurized air, the mass transfer of individual gas species between trapped gas phase and groundwater was studied. Field data on the dissolved gas composition in the groundwater were combined with a kinetic model on gas dissolution and transport in porous media. Phase mass transfer of individual gas components caused a temporary enrichment of nitrogen, and to a lower degree of methane, in trapped gas leading to the formation of excess dissolved nitrogen levels downgradient from the dissolving gas phase. By applying a novel gas sampling method for dissolved gases in groundwater it was shown that dissolved nitrogen can be used as a partitioning tracer to indicate complete gas dissolution in porous media. KW - Inter-phase mass transfer KW - Groundwater KW - Remediation KW - Gas sparging KW - Nitrogen KW - Methane KW - Kinetics KW - Bitterfeld Y1 - 2011 U6 - https://doi.org/10.1016/j.jconhyd.2011.05.005 SN - 0169-7722 VL - 126 IS - 1-2 SP - 8 EP - 18 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Al-Mashaikhi, K. A1 - Oswald, Sascha A1 - Attinger, Sabine A1 - Büchel, G. A1 - Knöller, K. A1 - Strauch, G. T1 - Evaluation of groundwater dynamics and quality in the Najd aquifers located in the Sultanate of Oman JF - Environmental earth sciences N2 - The Najd, Oman, is located in one of the most arid environments in the world. The groundwater in this region is occurring in four different aquifers A to D of the Hadhramaut Group consisting mainly of different types of limestone and dolomite. The quality of the groundwater is dominated by the major ions sodium, calcium, magnesium, sulphate, and chloride, but the hydrochemical character is varying among the four aquifers. Mineralization within the separate aquifers increases along the groundwater flow direction from south to north-northeast up to high saline sodium-chloride water in aquifer D in the northeast area of the Najd. Environmental isotope analyses of hydrogen and oxygen were conducted to monitor the groundwater dynamics and to evaluate the recharge conditions of groundwater into the Najd aquifers. Results suggest an earlier recharge into these aquifers as well as ongoing recharge takes place in the region down to present day. Mixing of modern and submodern waters was detected by water isotopes in aquifer D in the mountain chain (Jabal) area and along the northern side of the mountain range. In addition, delta H-2 and delta O-18 variations suggest that aquifers A, B, and C are assumed to be connected by faults and fractures, and interaction between the aquifers may occur. Low tritium concentrations support the mixing assumption in the recharge area. The knowledge about the groundwater development is an important factor for the sustainable use of water resources in the Dhofar region. KW - Environmental isotopes KW - Groundwater KW - Najd aquifer KW - Oman KW - Recharge KW - Water quality Y1 - 2012 U6 - https://doi.org/10.1007/s12665-011-1331-2 SN - 1866-6280 VL - 66 IS - 4 SP - 1195 EP - 1211 PB - Springer CY - New York ER -