Retention potential analysis of river restoration and floodplain measures in different catchments of Bavaria, Germany

2020 ◽  
Author(s):  
Michael Neumayer ◽  
Sonja Teschemacher ◽  
Fabian Merk ◽  
Markus Disse
Keyword(s):  
Spatial Scales ◽  
Flood Management ◽  
Peak Discharge ◽  
Mitigation Strategies ◽  
General View ◽  
Flood Events ◽  
River Channels ◽  
Management Decisions ◽  
Floodplain Restoration ◽  
Restoration Measures

<p>Nature-based solutions are an important component of integrated flood mitigation strategies for improving both the protection against hazardous flood events and the ecological conditions of river-floodplain systems. In order to be able to take these types of measures into account in upcoming flood management decisions, it must be possible to reliably estimate their effects on flood events. Therefore, this study focuses on a more general view on the catchment dependent contribution of combined river and floodplain restoration measures to the strengthening of river retention and flood protection. Furthermore, the importance of considering site-specific circumstances (e.g., the superposition of the flood waves of the main river and its tributaries), is evaluated.</p><p>The study is based on five investigation areas in Bavaria (Germany) with various topographic properties and different spatial scales (~ 90 – 560 km<sup>2</sup>). For each catchment, a physically based hydrological model (WaSiM) was coupled with the two-dimensional hydrodynamic model HYDRO_AS-2D by means of direct and diffuse inflow boundary conditions. Five flood events with various rainfall characteristics (advective/convective) and different return periods (5, 20 and 100 years) were generated with WaSiM. The holistic restoration scenarios are implemented by catchment dependent modifications of river channels and floodplains. As the aim of this study is to analyze the maximum possible efficiency of the restoration scenarios, it is assumed that almost the entire floodplain is available for the implementation of these measures. Highly restricted areas (e.g., settlement & industrial areas, important infrastructure) are excluded from this assumption. First results show that the peak discharge attenuations resulting from the restoration measures are exemplarily dependent on the characteristics of the floodplains (e.g., slope and extent) and the volumes of the flood events. It could be shown that the largest peak discharge attenuations (up to 28 %) and retardation (up to 8 h) occur in catchments with relatively flat and wide floodplains in combination with comparatively small flood volumes. Furthermore, the effectiveness of these measures can be considerably affected by local superposition effects with incoming tributaries. These effects can have site and event specific positive or negative impacts on the peak discharges and may not be neglected when planning restoration measures.</p><p>Based on these investigations, it is possible to evaluate if catchments are likely to be suitable for river and floodplain restoration in the course of flood management decisions. However, the effectiveness of the measures is always influenced by a combination of many area-specific factors that can only be predicted to a limited extent and therefore requires the modelling of an area.</p>

scholarly journals Reporting flood damages: a model for consistent, complete and multi-purpose scenarios

2016 ◽  
Author(s):  
Scira Menoni ◽  
Daniela Molinari ◽  
Francesco Ballio ◽  
Guido Minucci ◽  
Funda Atun ◽  
...  
Keyword(s):  
Time Window ◽  
Risk Mitigation ◽  
Spatial Scales ◽  
Flood Damage ◽  
Mitigation Strategies ◽  
Flood Events ◽  
Damage Mechanisms ◽  
Ex Post ◽  
The One ◽  
Available Information

Abstract. Effective flood risk mitigation requires that the impacts of flood events would be much better and more reliably known than is currently the case. Available post flood damage assessments usually supply only a partial vision of the consequences of the floods as they typically respond to the specific needs of a particular stakeholder. Coherently, they generally focus (i) on particular items at risk, (ii) on a certain time window after the occurrence of the flood, (iii) on a specific scale of analysis or (iv) on the analysis of damage only without an investigation of damage mechanisms and root causes. This paper responds to the necessity of a more integrated interpretation of flood events as the base to address the variety of needs arising after a disaster. In particular, a model is supplied to develop multi-purposes complete event scenarios. The model organizes available information in the post event according to five logical axes. This way, post-flood damage assessments can be developed that (i) are multisectoral, (ii) address the spatial scales that are relevant for the event at stake depending on the type of damage, i.e. direct, functional, systemic, that has to be analyzed, (iii) consider the temporal evolution of damage, and finally (iv) allow to understand damage mechanisms and root causes. All the above features are key for the multi-usability of resulting flood scenarios. The model allows, on the one hand, the rationalization of efforts currently implemented in ex-post damage assessments. On the other hand, integrated interpretations of flood events are fundamental to tailor and optimize flood mitigation strategies, as corroborated by the implementation of the model in a case study.

scholarly journals Flood damage: a model for consistent, complete and multipurpose scenarios

2016 ◽  
Vol 16 (12) ◽  
pp. 2783-2797 ◽  
Author(s):  
Scira Menoni ◽  
Daniela Molinari ◽  
Francesco Ballio ◽  
Guido Minucci ◽  
Ouejdane Mejri ◽  
...  
Keyword(s):  
Time Window ◽  
Risk Mitigation ◽  
Spatial Scales ◽  
Flood Damage ◽  
Mitigation Strategies ◽  
Flood Events ◽  
Damage Mechanisms ◽  
Ex Post ◽  
The One ◽  
Available Information

Abstract. Effective flood risk mitigation requires the impacts of flood events to be much better and more reliably known than is currently the case. Available post-flood damage assessments usually supply only a partial vision of the consequences of the floods as they typically respond to the specific needs of a particular stakeholder. Consequently, they generally focus (i) on particular items at risk, (ii) on a certain time window after the occurrence of the flood, (iii) on a specific scale of analysis or (iv) on the analysis of damage only, without an investigation of damage mechanisms and root causes. This paper responds to the necessity of a more integrated interpretation of flood events as the base to address the variety of needs arising after a disaster. In particular, a model is supplied to develop multipurpose complete event scenarios. The model organizes available information after the event according to five logical axes. This way post-flood damage assessments can be developed that (i) are multisectoral, (ii) consider physical as well as functional and systemic damage, (iii) address the spatial scales that are relevant for the event at stake depending on the type of damage that has to be analyzed, i.e., direct, functional and systemic, (iv) consider the temporal evolution of damage and finally (v) allow damage mechanisms and root causes to be understood. All the above features are key for the multi-usability of resulting flood scenarios. The model allows, on the one hand, the rationalization of efforts currently implemented in ex post damage assessments, also with the objective of better programming financial resources that will be needed for these types of events in the future. On the other hand, integrated interpretations of flood events are fundamental to adapting and optimizing flood mitigation strategies on the basis of thorough forensic investigation of each event, as corroborated by the implementation of the model in a case study.

scholarly journals Semantic model for flood management

2012 ◽  
Vol 14 (4) ◽  
pp. 918-936 ◽  
Author(s):  
Julián Garrido ◽  
Ignacio Requena ◽  
Stefano Mambretti
Keyword(s):  
Risk Assessment ◽  
Conceptual Framework ◽  
Environmental Assessment ◽  
Risk Evaluation ◽  
Evaluation Process ◽  
Flood Management ◽  
Semantic Model ◽  
Effective Management ◽  
Flood Events ◽  
Qualified Personnel

Risk assessment involves the study of vulnerability and hazards. When focused on flood events, such an analysis should evidently include the theoretical and practical study of floods and their behavior. Nevertheless, risk assessment is not useful if the results are not subsequently used for more effective management and planning by local authorities and qualified personnel. The risk evaluation process is composed of a set of actions, each of which requires different inputs. In fact, the results of one action are used as the input for another. This paper describes a semantic model for the study and management of floods with a view to elaborating a conceptual framework and designing a knowledge base. The model is based on the environmental assessment ontology and demonstrates how a brief ontology can be generated.

Examples of Floodplain Restoration Evaluation Studies in the Danube River Basin

2021 ◽  
Author(s):  
Francesca Perosa ◽  
Marion Gelhaus ◽  
Veronika Zwirglmaier ◽  
Leonardo F. Arias-Rodriguez ◽  
Aude Zingraff-Hamed ◽  
...  
Keyword(s):  
River Basin ◽  
Evaluation Studies ◽  
Danube River ◽  
Floodplain Restoration ◽  
The Danube River ◽  
Danube Catchment ◽  
General Benefit ◽  
Work Done ◽  
Restoration Measures ◽  
Danube River Basin

<p>Countries located in the Danube River Basin (DRB) are in danger of being affected by major catastrophic floods along the Danube and its tributaries. Floodplain restoration measures are among win-win nature-based solutions (NBS) for flood risk reduction but practitioners see their limitations in comparison to technical measures, when looking at their effectiveness and profitability. Within the framework of the EU Interreg Danube Floodplain project, this presentation shows the benefits of floodplain restoration in terms of monetized ecosystem services (ES). Our work focused on multiple ES groups for four study areas in the Danube catchment, located in Czech Republic, Romania, Serbia, and Slovenia. This was done with the help of stakeholder engagement, hydrodynamic models results, and the Toolkit for Ecosystem Service Site-Based Assessment (TESSA). Moreover, the approach was complemented with alternative methodologies (e.g. surveys on social media). Results show positive annual combined benefits of floodplain restoration measures, suggesting the helpfulness of evaluating these NBS through ES assessment. The work done will help increasing the knowledge on floodplain and their ES, and on how to rapidly evaluate them. Moreover, it will bring decision-makers further evidence in favor of floodplain restoration measures to be implemented for a general benefit of the communities.</p>

Geomorphological numerical modelling of woody dams in CAESAR-Lisflood

2021 ◽  
Author(s):  
Josh Wolstenholme ◽  
Christopher Skinner ◽  
David Milan ◽  
Daniel Parsons
Keyword(s):  
Flood Risk ◽  
Flood Management ◽  
River Channels ◽  
Sensitivity Testing ◽  
Spatial And Temporal Scales ◽  
Natural Processes ◽  
Natural Wood ◽  
Long Term Impact ◽  
Morphology Influence

<p>Natural flood management (NFM) promotes the sustainable enhancement of natural fluvial processes to reduce flooding (SEPA, 2015; Wilkinson et al., 2019), and is increasingly popular for use by community groups, contractors and governments (Kay et al., 2019). Reintroduction of wood to a river channel is a popular form of NFM often achieved through seeding natural logjams, or with an emphasis on engineering through installing woody dams (WDs). WDs are currently installed or being installed in catchments in an effort to reduce flood risk, through hydrograph attenuation, increase biodiversity and improve geomorphic heterogeneity (Wenzel et al., 2014; Burgess-Gamble et al., 2017; Grabowski et al., 2019). A further objective is to emulate the effect of natural wood found in river channels by partially, or completely, blocking the channel to accelerate the recruitment of natural wood as part of the natural wood cycle (Addy & Wilkinson, 2016).</p><p>There is a growing body of evidence supporting the benefits of NFM, however, the hydrogeomorphic effects of WDs are less well understood (Dadson et al., 2017). There is little scientific underpinning concerning the long-term impact of these features upon hydrogeomorphology at reach and catchment-scales. Very few numerically based studies consider the influence of sediment transport on WDs, and how changes in local bed morphology influence their effectiveness. Most NFM research to date has focused upon modelling the effectiveness of local NFM measures in small catchments (<10 km<sup>2</sup>) (Dadson et al., 2017), with less work evident at larger spatial and temporal scales (Kay et al., 2019; Wilkinson et al., 2019).</p><p>There is a need for a verified tool that is able to represent WDs accounting for geomorphic processes and interactions between the dams and morphodynamics, different design specifications of dams, and changing efficacy due to geomorphic evolution. We present the new CAESAR-Lisflood (Coulthard et al., 2013) “Working with Natural Processes” toolkit, capable of representing WDs across a digital experimental environment. Global sensitivity testing was conducted using the Morris method (Morris, 1991) to assess the sensitivity of five aspects of the toolkit, and their potentially influences on geomorphology and flood risk reduction.</p>

A Modified Chezy Formula for One-Dimensional Unsteady Frictional Resistance in Open Channel Flow

2021 ◽  
Vol 143 (5) ◽  
Author(s):  
Junwei Zhou ◽  
Weimin Bao ◽  
Geoffrey R. Tick ◽  
Hamed Moftakhari ◽  
Yu Li ◽  
...  
Keyword(s):  
Unsteady Flow ◽  
Frictional Resistance ◽  
Mitigation Strategies ◽  
Flood Routing ◽  
Flood Events ◽  
Complex Flow ◽  
Cross Sectional ◽  
Friction Resistance ◽  
Flow Unsteadiness ◽  
Better Than

Abstract It has been observed in literature that for unsteady flow conditions the one-to-one relationships between flow depth, cross-sectional averaged velocity, and frictional resistance as determined from steady uniform flow cases may not be appropriate for these more complex flow systems. Thus, a general friction resistance formula needs to be modified through the addition of new descriptive terms to account for flow unsteadiness, in order to eliminate errors due to uniform and steady-flow assumptions. An extended Chezy formula incorporating both time and space partial derivatives of hydraulic parameters was developed using dimensional analysis to investigate the relationship between flow unsteadiness and friction resistance. Results show that the proposed formula performs better than the traditional Chezy formula for simulating real hydrograph cases whereby both formula coefficients are individually identified for each flood event and coefficients are predetermined using other flood events as calibration cases. Although the extended Chezy formula as well as the original Chezy formula perform worse with the increasing degree of flow unsteadiness, its results are less dramatically affected by unsteadiness intensity, thereby improving estimations of flood routing. As a result, it tends to perform much better than traditional Chezy formula for severe flood events. Under more complex conditions whereby peak flooding events may occur predominantly under unsteady flow, the extended Chezy model may provide as a valuable tool for researchers, practitioners, and water managers for assessing and predicting impacts for flooding and for the development of more appropriate mitigation strategies and more accurate risk assessments.

scholarly journals Local spatial structure of forest biomass and its consequences for remote sensing of carbon stocks

2014 ◽  
Vol 11 (23) ◽  
pp. 6827-6840 ◽  
Author(s):  
M. Réjou-Méchain ◽  
H. C. Muller-Landau ◽  
M. Detto ◽  
S. C. Thomas ◽  
T. Le Toan ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Spatial Variability ◽  
Spatial Scales ◽  
Forest Biomass ◽  
Remote Sensing Data ◽  
Field Measurements ◽  
Forest Degradation ◽  
Forest Carbon ◽  
Mitigation Strategies ◽  
Large Plot

Abstract. Advances in forest carbon mapping have the potential to greatly reduce uncertainties in the global carbon budget and to facilitate effective emissions mitigation strategies such as REDD+ (Reducing Emissions from Deforestation and Forest Degradation). Though broad-scale mapping is based primarily on remote sensing data, the accuracy of resulting forest carbon stock estimates depends critically on the quality of field measurements and calibration procedures. The mismatch in spatial scales between field inventory plots and larger pixels of current and planned remote sensing products for forest biomass mapping is of particular concern, as it has the potential to introduce errors, especially if forest biomass shows strong local spatial variation. Here, we used 30 large (8–50 ha) globally distributed permanent forest plots to quantify the spatial variability in aboveground biomass density (AGBD in Mg ha–1) at spatial scales ranging from 5 to 250 m (0.025–6.25 ha), and to evaluate the implications of this variability for calibrating remote sensing products using simulated remote sensing footprints. We found that local spatial variability in AGBD is large for standard plot sizes, averaging 46.3% for replicate 0.1 ha subplots within a single large plot, and 16.6% for 1 ha subplots. AGBD showed weak spatial autocorrelation at distances of 20–400 m, with autocorrelation higher in sites with higher topographic variability and statistically significant in half of the sites. We further show that when field calibration plots are smaller than the remote sensing pixels, the high local spatial variability in AGBD leads to a substantial "dilution" bias in calibration parameters, a bias that cannot be removed with standard statistical methods. Our results suggest that topography should be explicitly accounted for in future sampling strategies and that much care must be taken in designing calibration schemes if remote sensing of forest carbon is to achieve its promise.

scholarly journals Urbanization and Increasing Flood Risk in the Northern Coast of Central Java—Indonesia: An Assessment towards Better Land Use Policy and Flood Management

Land ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 343
Author(s):  
Wiwandari Handayani ◽  
Uchendu Eugene Chigbu ◽  
Iwan Rudiarto ◽  
Intan Hapsari Surya Putri
Keyword(s):  
Land Use ◽  
River Basin ◽  
Spatial Data ◽  
Urban Areas ◽  
Landsat Imagery ◽  
Flood Management ◽  
Spatial Data Analysis ◽  
Northern Coast ◽  
Flood Events ◽  
Central Java

This study explores urbanization and flood events in the northern coast of Central Java with river basin as its unit of analysis. Two types of analysis were applied (i.e., spatial data and non-spatial data analysis) at four river basin areas in Central Java—Indonesia. The spatial analysis is focused on the assessment of LULC change in 2009–2018 based on Landsat Imagery. The non-spatial data (i.e., rural-urban classification and flood events) were overlaid with results of spatial data analyses. Our findings show that urbanization, as indicated by the growth rate of built-up areas, is very significant. Notable exposure to flood has taken place in the urban and potentially urban areas. The emerging discussion indicates that river basins possess dual spatial identity in the urban system (policy- and land-use-related). Proper land use planning and control is an essential instrument to safeguard urban areas (such as the case study area) and the entire island of Java in Indonesia. More attention should be put upon the river basin areas in designing eco-based approach to tackle the urban flood crises. In this case, the role of governance in flood management is crucial.

scholarly journals Extending the Predictability of Hydrometeorological Flood Events Using Radar Rainfall Nowcasting

2006 ◽  
Vol 7 (4) ◽  
pp. 660-677 ◽  
Author(s):  
Enrique R. Vivoni ◽  
Dara Entekhabi ◽  
Rafael L. Bras ◽  
Valeriy Y. Ivanov ◽  
Matthew P. Van Horne ◽  
...  
Keyword(s):  
Lead Time ◽  
Flash Flood ◽  
Spatial Scales ◽  
Surface Characteristics ◽  
Hydrologic Model ◽  
Flood Events ◽  
Catchment Scale ◽  
Radar Rainfall ◽  
Time Operation ◽  
Forecast Lead Time

Abstract The predictability of hydrometeorological flood events is investigated through the combined use of radar nowcasting and distributed hydrologic modeling. Nowcasting of radar-derived rainfall fields can extend the lead time for issuing flood and flash flood forecasts based on a physically based hydrologic model that explicitly accounts for spatial variations in topography, surface characteristics, and meteorological forcing. Through comparisons to discharge observations at multiple gauges (at the basin outlet and interior points), flood predictability is assessed as a function of forecast lead time, catchment scale, and rainfall spatial variability in a simulated real-time operation. The forecast experiments are carried out at temporal and spatial scales relevant for operational hydrologic forecasting. Two modes for temporal coupling of the radar nowcasting and distributed hydrologic models (interpolation and extended-lead forecasting) are proposed and evaluated for flood events within a set of nested basins in Oklahoma. Comparisons of the radar-based forecasts to persistence show the advantages of utilizing radar nowcasting for predicting near-future rainfall during flood event evolution.

Sign in / Sign up

Export Citation Format

Share Document