scholarly journals Compound flood modelling framework for rainfall-groundwater interactions

2021 ◽  
Author(s):  
Francisco Peña ◽  
Fernando Nardi ◽  
Assefa Melesse ◽  
Jayantha Obeysekera ◽  
Fabio Castelli ◽  
...  

Abstract. Compound floods are an active area of research where the complex interaction between pluvial, fluvial, coastal or groundwater flooding are analyzed. A number of studies have simulated the compound flooding impacts of precipitation, river discharge and storm surge variables with different numerical models and linking techniques. However, groundwater flooding is often neglected in flood risk assessments due to its sporadic frequency - as most regions have water tables sufficiently low that do not exacerbate flooding conditions -, isolated impacts and considerably less severity in respect to other types of flooding. This paper presents a physically-based, loosely-coupled modelling framework using FLO-2D and MODFLOW-2005 that is capable to simulate surface-subsurface water interactions to represent compound flooding events in North Miami. FLO-2D, responsible of the surface hydrology and infiltration processes, transfers the infiltration volume as recharge to MODFLOW-2005 until the soil absorption capacity is exceeded, while MODFLOW-2005 return exchange flow to the surface when groundwater heads are higher than the surface depth. The model calibration is based on three short-lived storm events that as individual processes represent minimum flooding conditions but in combination with pre-existing high-water table levels results in widespread flooding across the study area. Understanding groundwater flood risk is of particular interest to low-elevation coastal karst environments as the sudden emergence of the water table at ground surface can result in social disruption, adverse effects to essential services and damage infrastructure. Results are validated using FEMA’s severe repetitive loss (SRL) property records and crowdsourced data. Further research should assess the exacerbated impacts of high tides and sea level rise on water tables under current and future climate projections.

1985 ◽  
Vol 65 (2) ◽  
pp. 293-307 ◽  
Author(s):  
J. J. MILLER ◽  
D. F. ACTON ◽  
R. J. ST. ARNAUD

The results of this study indicate the importance of groundwater flow and water table depth on the genesis, characteristics and distribution of soils within a hummocky morainal landscape. Non-saline and non-carbonated soils in upland depressions can be attributed to "depression-focused" recharge by snowmelt and snowmelt runoff in the spring, as evidenced by deep sola and/or eluvial horizons. Non-saline and carbonated soils on lower slopes adjacent to depressions are associated with local discharge and/or lateral flow from the adjacent groundwater mounds under the depressions in spring, as well as upward flow in the summer resulting from water use by phreatophytes such as willows, creating a water table depression around the slough fringes. Saline and carbonated soils at low elevations are associated with shallow and rather stable water tables, and local discharge from surrounding uplands. Soil types on uplands are more dependent on slope position and infiltration than on depth to water table or groundwater flow. Non-saline soils of different profile types occur on mid- and upper slope positions. These areas have a deep water table with mainly recharge or lateral flow occurring in the saturated zone. The infiltration of surface runoff water in upland depressions is the dominant factor influencing the distribution of soluble salts in this hummocky landscape. Key words: Water table, landscape position, recharge, discharge, soluble salts, soil genesis, morphology, carbonate soil


2018 ◽  
Vol 7 (3.10) ◽  
pp. 120
Author(s):  
T Subramani ◽  
S Mathialagan

Geo-hydrology and groundwater exploration manner to pick out and to find the zone of recharge of groundwater in a precise river basin or a catchment .water level contour traces (or waft traces) are much like topographic strains on a map. They fully represent "elevations" in the subsurface. Water table contour lines can be used to inform which manner groundwater will glide in a given region. Plenty of wells are drilled and the hydraulic head is measured in each one. Water desk contours are drawn that be a part of areas of identical head .The ones water table contours lines are also called equipotential strains. Bear in mind: groundwater usually movements from a place of the higher hydraulic head to an area of decrease hydraulic head, and perpendicular to equipotential traces. In our challenge, we put into effect concept of water table contour map and geohydrological studies on Krishnagiri using GIS software program which plays the essential position in contemporary technology.  


Hydrology ◽  
2021 ◽  
Vol 8 (4) ◽  
pp. 146
Author(s):  
Javier Fernández-Pato ◽  
Pilar García-Navarro

Numerical simulation of flows that consider interaction between overland and drainage networks has become a practical tool to prevent and mitigate flood situations in urban environments, especially when dealing with intense storm events, where the limited capacity of the sewer systems can be a trigger for flooding. Additionally, in order to prevent any kind of pollutant dispersion through the drainage network, it is very interesting to have a certain monitorization or control over the quality of the water that flows in both domains. In this sense, the addition of a pollutant transport component to both surface and sewer hydraulic models would benefit the global analysis of the combined water flow. On the other hand, when considering a realistic large domain with complex topography or streets structure, a fine spatial discretization is mandatory. Hence the number of grid cells is usually very large and, therefore, it is necessary to use parallelization techniques for the calculation, the use of Graphic Processing Units (GPU) being one of the most efficient due to the leveraging of thousands of processors within a single device. In this work, an efficient GPU-based 2D shallow water flow solver (RiverFlow2D-GPU) is fully coupled with EPA’s Storm Water Management Model (SWMM). Both models are able to develop a transient water quality analysis taking into account several pollutants. The coupled model, referred to as RiverFlow2D-GPU UD (Urban Drainge) is applied to three real-world cases, covering the most common hydraulic situations in urban hydrology/hydraulics. A UK Environmental Agency test case is used as model validation, showing a good agreement between RiverFlow2D-GPU UD and the rest of the numerical models considered. The efficiency of the model is proven in two more complex domains, leading to a >100x faster simulations compared with the traditional CPU computation.


2021 ◽  
Author(s):  
Remi Meynadier ◽  
Hugo Rakotoarimanga ◽  
Madeleine-Sophie Deroche ◽  
Sylvain Buisine

<p>The large-scale and complex nature of climate change makes it difficult to assess and quantify the impact on insurance activities. Climate change is likely affecting the probability of natural hazard occurrence in terms of severity and/or frequency.</p><p>Natural catastrophe risk is a function of hazard, exposure and vulnerability. As a (re)-insurer it is seen that changes in year-on-year losses are a function of all these components and not just the hazard.</p><p>The present study focuses, in a first step, on assessing impacts of climate change on fluvial flood risks in Europe solely due to changes in hazard itself. A stochastic catalogue of future flood risk events is derived from Pan-European data sets of river flood probability of occurrence produced within EU FP7 RAIN project. The loss modelling framework internally developed at AXA is then used to provide a geographical view of changes in future flood risks.</p><p> </p>


2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Jiamin Wan ◽  
Tetsu K. Tokunaga ◽  
Kenneth H. Williams ◽  
Wenming Dong ◽  
Wendy Brown ◽  
...  

AbstractAlthough bedrock weathering strongly influences water quality and global carbon and nitrogen budgets, the weathering depths and rates within subsurface are not well understood nor predictable. Determination of both porewater chemistry and subsurface water flow are needed in order to develop more complete understanding and obtain weathering rates. In a long-term field study, we applied a multiphase approach along a mountainous watershed hillslope transect underlain by marine shale. Here we report three findings. First, the deepest extent of the water table determines the weathering front, and the range of annually water table oscillations determines the thickness of the weathering zone. Below the lowest water table, permanently water-saturated bedrock remains reducing, preventing deeper pyrite oxidation. Secondly, carbonate minerals and potentially rock organic matter share the same weathering front depth with pyrite, contrary to models where weathering fronts are stratified. Thirdly, the measurements-based weathering rates from subsurface shale are high, amounting to base cation exports of about 70 kmolc ha−1 y−1, yet consistent with weathering of marine shale. Finally, by integrating geochemical and hydrological data we present a new conceptual model that can be applied in other settings to predict weathering and water quality responses to climate change.


1974 ◽  
Vol 14 (71) ◽  
pp. 811 ◽  
Author(s):  
FG Abd-El-Kaddous

In 1968 and 1969, at Kerang, Victoria, the dry matter yield of oats (Avena byzantina) grown on a sodic soil were measured under conditions of fluctuating saline (31 mmhos cm-1) water tables. In each year, a water table was established for 14 days at one of three growth stages and at depths varying from 7.5 to 90 cm. Relative to the yield obtained when the water table remained at 90 cm depth, dry matter yields were reduced by 70 per cent (1968) and 79 per cent (1969) by one temporary water table rise to a depth of 7.5 cm for 14 days. Intermediate reductions in yields occurred when the water tables rose temporarily to intermediate depths from 82.5 cm to 15 cm (7.5 cm intervals). The growth stage at which the water table rise occurred had no significant effect on yield, except in the second period in 1969 when yield was reduced during conditions of high temperature and low evaporation.


Author(s):  
B R Rajasree ◽  
M C Deo

The estimation of shoreline change as well as sediment transport at a specified site can be reliably made with the help of corresponding numerical models that are run with the help of historical wave data generated using windwave models based on the input of past wind conditions. It is well known that the magnitude and behavior of historical wind and waves would not remain same in future as a result of the climate change induced by global warming. (Komar et al., 2010). In this light the present study attempts to understand what happens if future wind and waves are generated using regional climate models (RCMs) and the shoreline change and sediment transport is determined on that basis instead of historical wind and wave data. Toward this we have considered there different types of shorelines, namely (a) an uninterrupted coastal stretch, (b) the coast interrupted by an artificial structure and (c) the coast interrupted by natural features. This study goes beyond an earlier one (Rajasree et al., 2016) in which only case (a) was discussed and where coastal vulnerability was not assessed.


Materials ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 4304
Author(s):  
Miroslaw Ferdynus ◽  
Patryk Rozylo ◽  
Michal Rogala

The paper presents the results of numerical tests of impact and energy absorption capacity of thin-walled columns, subjected to axial impact loading, made of aluminum alloy, and having a square cross-section and spherical indentations on their lateral surfaces. The numerical models were validated using an experiment that was conducted on the Instron CEAST 9350 High Energy System drop hammer. Material properties of the applied aluminum alloy were determined on the basis of a static tension test. The crushing behavior of the columns and some crashworthiness indicators were investigated. On the basis of the results of the conducted analyses, conclusions were drawn about the most beneficial design/constructional variants in terms of achieved crashworthiness parameters.


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