In search of robust flood risk management alternatives for the Netherlands

The Netherlands' policy for flood risk management is being revised in view of a sustainable development against a background of climate change, sea level rise and increasing socio-economic vulnerability to floods. This calls for a thorough policy analysis, which can only be adequate when there is agreement about the "framing" of the problem and about the strategic alternatives that should be taken into account.\ud \ud In support of this framing, we performed an exploratory policy analysis, applying future climate and socio-economic scenarios to account for the autonomous development of flood risks, and defined a number of different strategic alternatives for flood risk management at the national level. These alternatives, ranging from flood protection by brute force to reduction of the vulnerability by spatial planning only, were compared with continuation of the current policy on a number of criteria, comprising costs, the reduction of fatality risk and economic risk, and their robustness in relation to uncertainties.\ud \ud We found that a change of policy away from conventional embankments towards gaining control over the flooding process by making the embankments unbreachable is attractive. By thus influencing exposure to flooding, the fatality risk can be effectively reduced at even lower net societal costs than by continuation of the present policy or by raising the protection standards where cost-effectiv

On the relation between weather-related disaster impacts, vulnerability and climate change

Disasters such as floods, storms, heatwaves and droughts can have enormous implications for health, the environment and economic development. In this article, we address the question of how climate change might have influenced the impact of weather-related disasters. This relation is not straightforward, since disaster burden is not influenced by weather and climate events alone—other drivers are growth in population and wealth, and changes in vulnerability. We normalized disaster impacts, analyzed trends in the data and compared them with trends in extreme weather and climate events and vulnerability, following a 3 by 4 by 3 set-up, with three disaster burden categories, four regions and three extreme weather event categories. The trends in normalized disaster impacts show large differences between regions and weather event categories. Despite these variations, our overall conclusion is that the increasing exposure of people and economic assets is the major cause of increasing trends in disaster impacts. This holds for long-term trends in economic losses as well as the number of people affected. We also found similar, though more qualitative, results for the number of people killed; in all three cases, the role played by climate change cannot be excluded. Furthermore, we found that trends in historic vulnerability tend to be stable over time, despite adaptation measures taken by countries. Based on these findings, we derived disaster impact projections for the coming decades. We argue that projections beyond 2030 are too uncertain, not only due to unknown changes in vulnerability, but also due to increasing non-stationarities in normalization relations

Assessing flood risk at the global scale: model setup, results, and sensitivity

Globally, economic losses from flooding exceeded $19 billion in 2012, and are rising rapidly. Hence, there is an increasing need for global-scale flood risk assessments, also within the context of integrated global assessments. We have developed and validated a model cascade for producing global flood risk maps, based on numerous flood return-periods. Validation results indicate that the model simulates interannual fluctuations in flood impacts well. The cascade involves: hydrological and hydraulic modelling; extreme value statistics; inundation modelling; flood impact modelling; and estimating annual expected impacts. The initial results estimate global impacts for several indicators, for example annual expected exposed population (169 million); and annual expected exposed GDP ($1383 billion). These results are relatively insensitive to the extreme value distribution employed to estimate low frequency flood volumes. However, they are extremely sensitive to the assumed flood protection standard; developing a database of such standards should be a research priority. Also, results are sensitive to the use of two different climate forcing datasets. The impact model can easily accommodate new, user-defined, impact indicators. We envisage several applications, for example: identifying risk hotspots; calculating macro-scale risk for the insurance industry and large companies; and assessing potential benefits (and costs) of adaptation measures

Towards standardised evaluative measurement of nature impacts: two spatial planning case studies for major Dutch lakes.

In the assessment of complex spatial planning projects, the ecological impacts and socio-economic impacts are fundamental to the evaluation. The measurements of ecological impacts of spatial plans have to be integrated in a standardised way. In the present paper, we analyse two Dutch case studies and apply the standardised Threat-Weighted Ecological Quality Area measurement. This measurement is developed to evaluate projects with terrestrial impacts but has not yet been applied for water evaluations. We aim to show how the use of a common measurement tool incorporates both ecological quality and degree of threat on criteria in the EU Water Framework Directive and Nature 2000. The measurements discussed here derive from two cases of cost–benefit analysis: The first case is the Markermeer, the second largest lake of The Netherlands, and a study on water quality improvement and nature restoration; an artificial island will also be the setting for a new residential area. The second case study is on water level management carried out on the IJsselmeer, the largest lake in the country. Results of our analysis show the potential impacts with a standardised method to the spatial distribution and quality of the ecosystems

Balans van de leefomgeving 2014 : de toekomst is nú

De Balans van de Leefomgeving geeft parlement, kabinet en samenleving een feitelijk onderbouwd inzicht in de huidige kwaliteit van de fysieke leefomgeving. De Balans is de tweejaarlijkse peilstok van het PBL die aangeeft in hoeverre de door de politiek zelf ten doel gestelde leefomgevingskwaliteit tijdig wordt bereikt. De Balans van de Leefomgeving 2014 heeft als motto meegekregen: de toekomst is nú

Secondary production and energetics of the shrimp Caridina nilotica in Lake Victoria, East Africa: model development and application

Measurements of body mass, carbon content, respiration, growth, and egestion are combined in a model of secondary production by the tropical freshwater shrimp Caridina . The model is developed to permit its direct application to empirical data for abundances and size frequency distributions of field populations. Model calculations combined with population data for offshore Lake Victoria over a period of two years indicate that Caridina consume the equivalent of 2.2% of annual lake primary production. Present net annual secondary production by the shrimp is an order of magnitude greater than the present fishery yield of the lake. Detritus-fed experimental organisms evidently had assimilation efficiencies as low as 10% by model calculation.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/42892/1/10750_2004_Article_BF00031923.pd