scholarly journals Long-term development and effectiveness of private flood mitigation measures: an analysis for the German part of the river Rhine

2012 ◽  
Vol 12 (11) ◽  
pp. 3507-3518 ◽  
Author(s):  
P. Bubeck ◽  
W. J. W. Botzen ◽  
H. Kreibich ◽  
J. C. J. H. Aerts

Abstract. Flood mitigation measures implemented by private households have become an important component of contemporary integrated flood risk management in Germany and many other countries. Despite the growing responsibility of private households to contribute to flood damage reduction by means of private flood mitigation measures, knowledge on the long-term development of such measures, which indicates changes in vulnerability over time, and their effectiveness, is still scarce. To gain further insights into the long-term development, current implementation level and effectiveness of private flood mitigation measures, empirical data from 752 flood-prone households along the German part of the Rhine are presented. It is found that four types of flood mitigation measures developed gradually over time among flood-prone households, with severe floods being important triggers for an accelerated implementation. At present, still a large share of respondents has not implemented a single flood mitigation measure, despite the high exposure of the surveyed households to floods. The records of household's flood damage to contents and structure during two consecutive flood events with similar hazard characteristics in 1993 and 1995 show that an improved preparedness of the population led to substantially reduced damage during the latter event. Regarding the efficiency of contemporary integrated flood risk management, it is concluded that additional policies are required in order to further increase the level of preparedness of the flood-prone population. This especially concerns households in areas that are less frequently affected by flood events.

2007 ◽  
Vol 56 (4) ◽  
pp. 87-95 ◽  
Author(s):  
A. Winterscheid

It is now commonly accepted that the management of flood risks has to be fulfilled within an integrated framework. About two decades ago flood risk was managed from a limited perspective predominantly by means of structural measures aimed at flood control. In contrast integrated flood risk management incorporates the complete management cycle consisting of the phases prevention, protection and preparedness. In theory it is a well described concept. In the stage of implementation, however, there is often a lack of support although a consistent policy framework exists. Consequently, the degree of implementation must be rated as inadequate in many cases. In particular this refers to the elements which focus on preparedness and prevention. The study to which this paper refers emphasises the means and potentials of scenario technique to foster the implementation of potentially appropriate measures and new societal arrangements when applied in the framework of integrated flood risk management. A literature review is carried out to reveal the state-of-the-art and the specific problem framework within which scenario technique is generally being applied. Subsequently, it is demonstrated that scenario technique is transferable to a policy making process in flood risk management that is integrated, sustainable and interactive. The study concludes with a recommendation for three applications in which the implementation of measures of flood damage prevention and preparedness is supported by scenario technique.


Water ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 1884
Author(s):  
Ana Juárez ◽  
Knut Alfredsen ◽  
Morten Stickler ◽  
Ana Adeva-Bustos ◽  
Rodrigo Suárez ◽  
...  

Floods are among the most damaging of natural disasters, and flood events are expected to increase in magnitude and frequency with the effects of climate change and changes in land use. As a consequence, much focus has been placed on the engineering of structural flood mitigation measures in rivers. Traditional flood protection measures, such as levees and dredging of the river channel, threaten floodplains and river ecosystems, but during the last decade, sustainable reconciliation of freshwater ecosystems has increased. However, we still find many areas where these traditional measures are proposed, and it is challenging to find tools for evaluation of different measures and quantification of the possible impacts. In this paper, we focus on the river Lærdal in Norway to (i) present the dilemma between traditional flood measures and maintaining river ecosystems and (ii) quantify the efficiency and impact of different solutions based on 2D hydraulic models, remote sensing data, economics, and landscape metrics. Our results show that flood measures may be in serious conflict with environmental protection and legislation to preserve biodiversity and key nature types.


2011 ◽  
Vol 11 (12) ◽  
pp. 3293-3306 ◽  
Author(s):  
P. Bubeck ◽  
H. de Moel ◽  
L. M. Bouwer ◽  
J. C. J. H. Aerts

Abstract. Flood damage modelling is an important component in flood risk management, and several studies have investigated the possible range of flood damage in the coming decades. Generally, flood damage assessments are still characterized by considerable uncertainties in stage-damage functions and methodological differences in estimating exposed asset values. The high variance that is commonly associated with absolute flood damage assessments is the reason for the present study that investigates the reliability of estimates of relative changes in the development of potential flood damage. While studies that estimate (relative) changes in flood damage over time usually address uncertainties resulting from different projections (e.g. land-use characteristics), the influence of different flood damage modelling approaches on estimates of relative changes in the development of flood damage is largely unknown. In this paper, we evaluate the reliability of estimates of relative changes in flood damage along the river Rhine between 1990 and 2030 in terms of different flood-damage modelling approaches. The results show that relative estimates of flood damage developments differ by a factor of 1.4. These variations, which result from the application of different modelling approaches, are considerably smaller than differences between the approaches in terms of absolute damage estimates (by a factor of 3.5 to 3.8), or than differences resulting from land-use projections (by a factor of 3). The differences that exist when estimating relative changes principally depend on the differences in damage functions. In order to improve the reliability of relative estimates of changes in the development of potential flood damage, future research should focus on reducing the uncertainties related to damage functions.


Author(s):  
Vidyapriya V. ◽  
Ramalingam M.

Mostly populous city like Chennai is subjected to frequent flooding due to its complex nature of natural and man-made activities. From the analysis of the past records of flood events of 1943,1976,1985,2005 and 2008,it has been observed Adayar watershed is subjected to cataclysmic flooding in low-lying areas of the city and its suburbs because of inoperativeness of the local drainage system, rainfall associated with cyclonic activity, topography of the terrain, encroachments along the floodplain, hugh upstream flow discharge into the river and the highly impervious area which blocked the runoff to flow into the storm water drainage. After looking into these problems of flooding, a study have been conducted on Adayar watershed to develop a 2D hydrodynamic model for the two scenarios of existing condition of storm water drainage network and revised conditions of storm water drainage network using high resolution Lidar DEM to assess the volume of runoff with respect to time and duration on flood peaks for the two flood events of 2005 and 2015.Secondly to develop a 1D flood model to predict the river stages during peak floods using MIKE 11 for the Adayar watershed. Thirdly to integrate the coupled 1D and 2D model using MIKEFLOOD for assessing the extent of inundation in the floodplain area of Adayar river. Finally results from the integrated model have been validated and the results found satisfactory. As a part of mitigation measures, two flood mitigation measures have been adopted. One measure such as revised storm water drainage system which enhances the flood carrying capacity of the drains and results in less inundated area which solves the problem of urban flooding and second measure such as regrading the river bed which reduces the floodplain inundation around the adjacent area of the river. After adopting these measures, the river is free to flow into the sea without any blockades.


2020 ◽  
Author(s):  
Fabian Merk ◽  
Michael Neumayer ◽  
Sonja Teschemacher ◽  
Markus Disse

<p>Nature-based retention measures are an essential part of a sustainable and integrated flood protection strategy and can contribute to a holistic flood mitigation approach. Thereby river restoration measures such as channel widening, or flow path extension to increase the channel meandering represent successfully used components. Coupled with flood plain measures, retarding and retention effects of flood events are possible. These effects are commonly computed applying two-dimensional hydrodynamic modelling approaches. However, these developments rely on high spatial and temporal resolutions which are generally characterized by a high computational demand and are hence time and cost expensive. Thus, the evaluation and derivation of flood routing parameters to reproduce the resulting hydrodynamical processes in hydrological models can provide an effective and fast computation of river restoration scenarios.</p><p> </p><p>The objective in the present study is the derivation and application of flood routing parameters which can account for the effects of river restoration and flood plain measures in hydrological models. Further, this study aims to determine if the catchment and scale specific outcomes and parameter sets are also applicable to a broader range of catchments.</p><p>For this purpose, commonly applied flood routing approaches and the associated parameters used in hydrological models (e.g. the kinematic wave approach in the WaSiM model) are investigated for catchments of different scales in Bavaria (Germany) and for flood events of varying characteristics (e.g. return period, flood volume). To determine the effects of channel restoration and flood plain measures, two-dimensional hydrodynamic models (HYDRO_AS-2D) are set up to simulate the current state as well as restoration scenarios. Based on the simulation results of the hydrodynamic models, the parameters of the flood routing approaches are calibrated to match the catchment specific restoration effects for a first set of river sections. Catchment and scale dependent parameter sets (dominating valley type, flood plain slopes) are then derived to reproduce the specific river restoration. First results of the calibration of the parameter sets show a satisfying fit of the hydrological model to different restoration scenarios of the hydrodynamic model. For the validation of the derived parameter sets of the flood routing methods in the hydrological model additional river sections of the hydrodynamic models are subsequently investigated.</p><p>The implementation of the new flood routing parametrization of the hydrological models is finally examined as an alternative resource efficient way of calculating the effects of river restoration scenarios. Moreover, the applicability of the outcomes as a cost-efficient alternative compared to hydrodynamic models in land use planning and risk assessment is assessed and discussed within the frame of river restorations as flood mitigation measures.</p>


2015 ◽  
Vol 15 (6) ◽  
pp. 1297-1309 ◽  
Author(s):  
K. M. de Bruijn ◽  
F. Klijn ◽  
B. van de Pas ◽  
C. T. J. Slager

Abstract. For comprehensive flood risk management, accurate information on flood hazards is crucial. While in the past an estimate of potential flood consequences in large areas was often sufficient to make decisions on flood protection, there is currently an increasing demand to have detailed hazard maps available to be able to consider other risk-reducing measures as well. Hazard maps are a prerequisite for spatial planning, but can also support emergency management, the design of flood mitigation measures, and the setting of insurance policies. The increase in flood risks due to population growth and economic development in hazardous areas in the past shows that sensible spatial planning is crucial to prevent risks increasing further. Assigning the least hazardous locations for development or adapting developments to the actual hazard requires comprehensive flood hazard maps. Since flood hazard is a multi-dimensional phenomenon, many different maps could be relevant. Having large numbers of maps to take into account does not, however, make planning easier. To support flood risk management planning we therefore introduce a new approach in which all relevant flood hazard parameters can be combined into two comprehensive maps of flood damage hazard and flood fatality hazard.


2010 ◽  
Vol 10 (1) ◽  
pp. 1-2 ◽  
Author(s):  
C. M. Rheinberger

Abstract. This comment is meant to shed some light on the use of so-called "risk aversion functions" in the management of flood risks and other natural hazards as recently proposed in this journal (Merz et al., 2009). In particular, I resume the discussion as to whether the relative damage is a suitable indicator of risk aversion and lay out why the use of this indicator may lead to inefficient decisions upon flood mitigation measures.


2015 ◽  
Vol 23 (2) ◽  
pp. 240-255 ◽  
Author(s):  
Caroline Wenger

Many nations rely on dykes and levees to mitigate flood risk. However, a myriad of problems has prompted views that levees are ultimately maladaptive and should be used as a measure of last resort. This leads to questions not only about the place of levees in future flood risk management, but also whether anything can be done to reduce their impacts. A detailed review of flood events from Australia, China, the Netherlands, and the USA was used to develop a case study for each country. Case studies present existing levee problems, future flood threats, and national strategies to address them. These were used as a basis to analyse the transferability of adaptive flood approaches. While many countries are attempting to restore floodplain storage, thereby reducing their reliance on levees, others are increasing their investment in levee construction. This review explores factors that affect the transferability of adaptive approaches, including issues, such as problem recognition, affordability, and program delivery. It was found that countries vary in their ability to recognise levee problems, and the level at which decisions are made influences the likelihood of adaptive solutions being adopted. Analysis suggests that federal systems face particular challenges and their capacity to adopt adaptive approaches may be impaired if institutional barriers are not addressed. Regardless of the overall approach to manage flood risk, the experiences of all case study countries offer some broadly applicable lessons for improving the use and management of levees, reducing their adverse impacts, and improving the integration of natural flood mitigation.


2020 ◽  
Vol 30 (2) ◽  
pp. 133-157
Author(s):  
Suriya Saravanan ◽  
Mudgal Basavaraj ◽  
Prakash Nelliyat

AbstractFlood damage assessment plays a vital role in providing information to policy developers. Nowadays, due to urbanization, the impact of flooding on communities is extensive, including tangible damage to property, the environment, and infrastructure as well as intangible damage due to stress, health hazards, and hardship. This paper provides an overview of a detailed flood assessment study conducted in the Kotturpuram Housing board area, located on the flood plain of the Adayar River in Chennai, India. A relatively simple approach to data collection was adopted, being a Questionnaire Survey (QS) as well as semi-structured interviews and observation techniques, due to data and research limitations. Losses due to damage to belongings and extra spending to buy essential commodities during flooding are also dealt with in this study. The flood mitigation costs for flooding that occurred in the year 2015 are also evaluated. A stage-damage curve was arrived at based on the information collected. Optimal and sustainable mitigation measures can be achieved only when the socio-economic aspects are adequately considered. Thus, this analysis was designed to estimate the effects of flooding on a community’s social and economic welfare, and thereby help to educate the community, including residents and officials, about the impact and magnitude of flooding. The outputs of the study will be the key inputs for designing flood mitigation and relief measures.


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