1,721,130 research outputs found
On the use of SRTM and altimetry data for flood modeling in data-sparse regions
No full textThe growing availability of remotely sensed data has fostered the implementation of hydraulic modeling in poorly gauged regions. However, these applications suffer the lack of knowledge of river bathymetry, which cannot be directly inferred from satellite instruments. This study explores the possibility to set up, calibrate, and validate a hydrodynamic model which geometry is based on global and freely available satellite data. First, the study tests two different procedures for inferring the river bathymetry under the water surface level. Second, focusing on a Po River stretch of ∼140 km (Northern Italy), the study further assesses the suitability of spaceborne topographic and remotely sensed altimetry data (i.e.; ERS-2 and ENVISAT) for implementing and calibrating hydrodynamic models. Referring to 90 m SRTM (Shuttle Radar Topography Mission) digital elevation model for the representation of the riverbed morphology, the work analyzes the performances of different 1-D numerical models which cross sections are modified according to two approaches: (1) Channel Bankfull depth (CB) and (2) Slope-Break (SB) approach. The calibration and validation processes are performed by referring to extended altimetry time series (∼16 years of data), while the accuracy and trustworthiness of 1-D models are tested with reference to a quasi-2-D model based on detailed geometry data. Results show that both CB and SB approaches enhance the performance of SRTM-based models. In particular, the SB approach is completely based on satelliteborne data and shows Nash-Sutcliffe efficiency, MAE, and RMSE values similar to those obtained with the benchmark model
Brief communication: On the environmental impacts of the 2023 floods in Emilia-Romagna (Italy)
Full text link<jats:p>Abstract. The impacts of floods on environmental assets are often not assessed. In this communication, we reflect on this issue by analysing the reported environmental consequences of the 2023 Emilia-Romagna floods. The information on the environmental impacts is constructed by collecting data from reports, press releases, and interviews in the aftermath of the events. The most frequently reported damage involves water resources and water-related ecosystems, with cultural and supporting ecosystem services particularly affected. Indirect effects in time and space, intrinsic recovery capacity, cascade impacts on socio-economic systems, and the lack of established monitoring activities appear to be the most challenging aspects for future research.
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Exploiting the proliferation of current and future satellite observations of rivers
No full textFor about 20 years now, satellite data, in the form of imagery and
altimetry, have been used to study river hydrodynamics, floods and
floodplain inundation. Over the recent years, the number of scientific
papers in this field has considerably increased, and these papers have
presented very innovative research and methods for model calibration,
evaluation and assimilation as well as event reanalysis and forecasting.
This progress has led to a number of recent and upcoming satellite
missions that are already transforming current procedures and operations
in flood modelling and monitoring as well as our understanding of river
and floodplain hydrodynamics globally.
This commentary summarizes progress and discusses the current and
future proliferation of satellite observations of hydrodynamics and
presents a way forward of how to address this in order to make the most
use of the ever-increasing amount of Earth observation (EO) data available
for flood modelling, mapping and forecasting
Effetti della subsidenza antropica sulle dinamiche di inondazione: il caso studio di Ravenna
No full textAssessing the historical residual flood-risk evolution over large floodable areas: dependence of the results on the 2D hydrodynamic numerical model
Full text linkThis study investigates the evolution of the flood risk along the middle-lower reach of the River Po (length ~350 km,
Northern Italy). The analysis starts from the common perception that, due to a combination of different causes, the flood
risk is dramatically increasing in Europe and in other areas of the world, which is supported by the steadily increasing
economic flood losses recorded worldwide. We refer in particular to the residual flood-risk and we consider an inundation
scenario simulated by means of a simplified quasi-two-dimensional (quasi-2D) hydrodynamic model that reproduces the
hydraulic behavior of a large floodable area outside the main embankment system of the Po river (named “C-Buffer”) for
an exceptional flood event with a 500-year return period; then we perform a detailed flood risk assessment for different
land-use scenarios and population dynamics that have been observed for the C-Buffer over the last five decades. The
detailed flood-risk assessment refers separately to four hydraulic compartments located within the C-Buffer, which
according to the study inundation scenario are flooded during the exceptional event. In particular, the analyses use flooddamage
curves proposed in the literature coupled with a reproduction of the inundation dynamics simulated by two fully
two-dimensional (2D) hydrodynamic models based on 2D shallow water Saint-Venant equations: Hec-Ras 5.0 and
Telemac-2D. The former model has been recently released and enables users to perform combined one-dimensional (1D)
and 2D unsteady-flow simulations (i.e. combining 1D reaches and storage areas with 2D flow areas schematized with
finite-volume method), while the latter is a widely employed and well known 2D finite-element scheme. The comparison
enabled us to assess how recent land-use changes affected the residual risk in the study area and, indirectly, to quantify
the dependence of flood-risk assessments on the considered 2D model, i.e. Telemac-2D and the new Hec-Ras 5.0
Unraveling Long-Term Flood Risk Dynamics Across the Murray-Darling Basin Using a Large-Scale Hydraulic Model and Satellite Data
Full text linkRiver floods are one of the most devastating extreme hydrological events, with oftentimes
remarkably negative effects for human society and the environment. Economic losses
and social consequences, in terms of affected people and human fatalities, are increasing
worldwide due to climate change and urbanization processes. Long-term dynamics
of flood risk are intimately driven by the temporal evolution of hazard, exposure and
vulnerability. Although needed for effective flood risk management, a comprehensive
long-term analysis of all these components is not straightforward, mostly due to a
lack of hydrological data, exposure information, and large computational resources
required for 2-D flood model simulations at adequately high resolution over large spatial
scales. This study tries to overcome these limitations and attempts to investigate the
dynamics of different flood risk components in the Murray-Darling basin (MDB, Australia)
in the period 1973–2014. To this aim, the LISFLOOD-FP model, i.e., a large-scale 2-D
hydrodynamic model, and satellite-derived built-up data are employed. Results show
that the maximum extension of flooded areas decreases in time, without revealing any
significant geographical transfer of inundated areas across the study period. Despite
this, a remarkable increment of built-up areas characterizes MDB, with larger annual
increments across not-flooded locations compared to flooded areas. When combining
flood hazard and exposure, we find that the overall extension of areas exposed to high
flood risk more than doubled within the study period, thus highlighting the need for
improving flood risk awareness and flood mitigation strategies in the near future
Comparison of two modelling strategies for 2D large-scale flood simulations
Full text linkIn this paper, two emerging strategies for the reduction of the computational time of 2D large-scale flood simulations
are compared, with the aim of evaluating their strengths and limitations and of suggesting guidelines for
their effective application. The analysis is based on two state-of-the-art raster flood models with different governing
equations and parallelization strategies: PARFLOOD, a GPU-accelerated code that solves the fully dynamic
shallow water equations, and LISFLOOD-FP, which combines a parallel implementation for CPU with simplified
equations (local-inertial approximation). The results of two case studies (a river flood propagation, and a lowland
inundation) suggest that, at coarse grid resolutions, the parallelized simplified model LISFLOOD-FP can represent
a good alternative to fully dynamic models in terms of accuracy and runtime, while the GPU-parallel code
PARFLOOD is more efficient in case of high-resolution simulations with millions of cells, despite the greater
complexity of the numerical scheme
Industrial Pressures and Assessment of Biochemical River Quality: a Short-cut Methodology
No full textIn Europe, a comprehensive assessment of surface water bodies is hindered by a widespread deficiency in quality monitoring data, both spatially and temporally, which impedes sustainable water management. In light of this challenge, this paper proposes a multidisciplinary short-cut methodology to estimate the biochemical quality of rivers determined by primary anthropogenic pollution sources acting as the most significant pressure on surface water. The proposed methodology comprises three main steps: 1. Identifying primary anthropogenic pollution sources and assessing their relative expected pressures on river water, 2. Spatially allocating identified sources along the river using a raster-based approach, and 3. Assessing the overall biochemical state of surface water. The industrial activities considered significant for river quality deterioration include establishments under the Seveso Directive, activities subject to the IPPC-IED discipline, and wastewater treatment plants. Contaminated sites are also considered, representing former industrial activities that continue to indirectly impact water bodies. To address the scarcity of monitoring data, the methodology relies on accessible official documentation for the assessment. The methodology was applied to a river basin exposed to various industrial pressures in the North of Italy. The obtained results have been compared with available water quality records to check the methodology's ability to reproduce the trend of measured data along the main river stem. The results of this preliminary investigation suggest that the developed approach has the potential to be a valuable tool for assessing biochemical river quality in regions with limited monitoring data
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