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Flood risk quantification is a complex process involving a chain of models. The approach contains many uncertainties which accumulate in the calculated flood risk. Risk-based flood safety standards are therefore prone to large uncertainty. This study aims to quantify the uncertainty of risk-based flood safety standards for a Dutch riverine case study. Through a systematic approach using expert elicitation, the key uncertainty sources in the Dutch safety standard derivation are identified. Uncertainty magnitudes are quantified for five main sources of uncertainty, after which these uncertainties are propagated through the model chain in a scenario analysis to derive flood safety standards. The results show that the Dutch risk-based flood safety standards are highly uncertain given the relative uncertainty bandwidth of 70%. The flood safety standards are found to be most sensitive to damage function and evacuation uncertainty. Also, we show that the impact of uncertainty strongly depends on local characteristics. [ABSTRACT FROM AUTHOR]

Employing micro-data of Dutch local business units, we show that firm characteristics such as size, economic activity, the traded product portfolio, the focus of trade involvement and the geographic pattern of trade are important determinants of recovery following the trade collapse of 2008-2009, both in terms of speed and depth. Our findings suggest that post-crisis growth is faster for trade in goods further downstream of the value chain and thus closer to the final consumer. Trade recovery at the firm-level does not crucially hinge on locational factors such as the province in which a firm is located or regional revealed comparative advantages in particular product groups. [ABSTRACT FROM AUTHOR]

Logistic regression was used to analyse the relationship between six submerged macrophyte taxa (Chara spp., Potamogeton perfoliatus, Potamogeton pectinatus, Potamogeton pusillus, Myriophyllum spicatum, Alisma gramineum and sum of all species) and four environmental variables (turbidity, effective wind fetch, water depth and sediment silt percentage, including interactions and some quadratic terms). The models were based on intensive vegetation samples (total c. 72 000) and other monitoring data carried out in five Dutch shallow lakes in the IJsselmeer area from 1988 to 1998. Water depth and light extinction were the most important factors determining the occurrence of all studied species in Veluwemeer, while effective wind fetch had a moderate effect and sediment silt had only a minor effect on the occurrence. Water depth had a negative impact on all species, except A. gramineum, which showed an optimum response. Three species showed an optimum response at intermediate turbidity (M. spicatum, P. pusillus and P. pectinatus), whereas the other taxa were negatively related. Three species (Chara spp., P. perfoliatus and M. spicatum) were positively related to wind fetch or showed an optimum response at intermediate value, whereas P. pusillus, P. pectinatus and A. gramineum were negatively related. The models including interactions between the explanatory variables showed a high goodness of fit for Veluwemeer for Chara, P. pectinatus and M. spicatum (in more than 8 of 10 instances, a cell originally scored `1' are predicted to have a higher probability than the ones originally scored `0'). The models of the other species showed a moderate goodness of fit (between 6 and 8 of 10 instances correctly predicted). The models developed for Veluwemeer were valid for Chara in all the four other lakes (more than 8 of 10 instances correctly predicted), while the models of other species were valid in some instances. A succession of vegetation was recognised based on water depth and turbidity in Veluwemeer. P. perfoliatus and P. pectinatus dominated the shallow zones under turbid conditions, but a change to dominance by Chara occurred in clear water. Based on the observation of co-occurrence, competition has played an important role for the shift from P. pectinatus to Chara. Chara became dominant 2 years after initial colonisation of Chara in P. pectinatus beds. Competition between P. perfoliatus and Chara may have been of less importance, due to a more distinct habitat (deeper colonisation) of dense P. perfoliatus beds. The analysed species showed large differences in vegetation stability from year-to-year. Chara showed the highest year to year stability (c. 65% of the cells remained covered from one year to another), while A. gramineum showed the highest dynamics (c. 10% of the cells remained covered from one year to another). Species producing specialized vegetative propagules for over wintering showed a higher local stability than species without such propagules. [ABSTRACT FROM AUTHOR]