Rijkswaterstaat Center for Water Management

AA, Netherlands

Rijkswaterstaat Center for Water Management

AA, Netherlands
Time filter
Source Type

PubMed | Institute For Hygiene Und Umwelt, National Water Research Institute, Servicio de Radioisotopos, Physikalische Chemie and 23 more.
Type: | Journal: Applied radiation and isotopes : including data, instrumentation and methods for use in agriculture, industry and medicine | Year: 2016

The preparation and characterization of certified reference materials (CRMs) for radionuclide content in sediments collected offshore of Bikini Atoll (IAEA-410) and in the open northwest Pacific Ocean (IAEA-412) are described and the results of the certification process are presented. The certified radionuclides include: (40)K, (210)Pb ((210)Po), (226)Ra, (228)Ra, (228)Th, (232)Th, (234)U, (238)U, (239)Pu, (239+240)Pu and (241)Am for IAEA-410 and (40)K, (137)Cs, (210)Pb ((210)Po), (226)Ra, (228)Ra, (228)Th, (232)Th, (235)U, (238)U, (239)Pu, (240)Pu and (239+240)Pu for IAEA-412. The CRMs can be used for quality assurance and quality control purposes in the analysis of radionuclides in sediments, for development and validation of analytical methods and for staff training.

PubMed | Institute For Hygiene Und Umwelt, National Water Research Institute, European Commission, University of Barcelona and 24 more.
Type: | Journal: Applied radiation and isotopes : including data, instrumentation and methods for use in agriculture, industry and medicine | Year: 2014

A Certified Reference Material (CRM) for radionuclides in seaweed (Fucus vesiculosus) from the Baltic Sea (IAEA-446) is described and the results of the certification process are presented. The (40)K, (137)Cs, (234)U and (239+240)Pu radionuclides were certified for this material, and information values for 12 other radionuclides ((90)Sr, (99)Tc, (210)Pb ((210)Po), (226)Ra, (228)Ra, (228)Th, (230)Th, (232)Th, (235)U, (238)U, (239)Pu and (240)Pu) are presented. The CRM can be used for Quality Assurance/Quality Control of analysis of radionuclides in seaweed and other biota samples, as well as for development and validation of analytical methods, and for training purposes.

van der Grinten E.,Laboratory for Ecological Risk Assessment | Pikkemaat M.G.,Wageningen University | van den Brandhof E.-J.,Laboratory for Ecological Risk Assessment | Stroomberg G.J.,Rijkswaterstaat Center for Water Management | Kraak M.H.S.,University of Amsterdam
Chemosphere | Year: 2010

Antibiotics may affect both primary producers and decomposers, potentially disrupting ecosystem processes. Hence, it is essential to assess the impact of antibiotics on aquatic ecosystems. The aim of the present study was therefore to evaluate the potential of a recently developed test for detecting antibiotics in animal tissue, the Nouws Antibiotic Test (NAT), as a sensitive bioassay to assess the effects of antibiotics in water. To this purpose, we determined the toxicity of sulphamethoxazole, trimethoprim, flumequine, tylosin, streptomycin, and oxytetracycline, using the NAT adapted for water exposure. The sensitivity of the NAT was compared to that of bioassays with bacteria (Microtox), cyanobacteria and green algae. In the Microtox test with Vibrio fischeri as test organism, no effects were observed for any of the test compounds. For three of the six antibiotics tested, the cyanobacteria were more vulnerable than the green algae when using photosynthetic efficiency as an endpoint. The lowest EC50 values for four out of six tested antibiotics were obtained using the NAT bacterial bioassay. The bacterial plate system responded to antibiotics at concentrations in the μgL-1 and lower mgL-1 range and, moreover, each plate proved to be specifically sensitive to the antibiotics group it was designed for. It is concluded that the NAT bioassay adapted for water exposure is a sensitive test to determine the presence of antibiotics in water. The ability of this test to distinguish five major antibiotic groups is a very strong additional value. © 2010 Elsevier Ltd.

Rice J.,Northwest Atlantic Fisheries Center | Arvanitidis C.,Hellenic Center for Marine Research | Borja A.,Tecnalia | Frid C.,University of Liverpool | And 8 more authors.
Ecological Indicators | Year: 2012

The European Marine Strategy Framework Directive (MSFD) requires European states to maintain their marine waters in 'Good Environmental Status'. The MSFD includes 11 descriptors of "Good Environmental Status" (GES), including "Sea-floor Integrity". This descriptor is defined as: "Sea-floor integrity is at a level that ensures that the structure and functions of the ecosystems are safeguarded and benthic ecosystems, in particular, are not adversely affected." This contribution briefly summarizes the main conclusions of an international expert group established to review the scientific basis for making this concept operational. The experts concluded that consideration of 8 attributes of the seabed system would provide adequate information to meet requirements of the MSFD: (i) substratum, (ii) bioengineers, (iii) oxygen concentration, (iv) contaminants and hazardous substances, (v) species composition, (vi) size distribution, (vii) trophodynamics and (viii) energy flow and life history traits. The experts further concluded that "Good Environmental Status" cannot be defined exclusively as "pristine Environmental Status", but rather status when impacts of all uses were sustainable. Uses are sustainable if two conditions are met:the pressures associated with those uses do not hinder the ecosystem components to retain their natural diversity, productivity and dynamic ecological processesrecovery from perturbations such that the attributes lie within their range of historical natural variation must be rapid and secure. No single specific suite of indicators is proposed, both because no single set of indicators will meet the needs of all EU countries in all regional seas, and because according to the MSFD indicator selection is the prerogative of individual states. However, the need for conceptual consistency in assessing GES throughout European seas should be served if the selection of indicators and the integration of their information content in assessing GES follow the guidance in the report of the TG on Seafloor Integrity. This guidance is presented here in summary form. Informed by this report European Commission selected as indicators for the Sea-floor Integrity: (i) type, abundance, biomass and areal extent of relevant biogenic substrate; (ii) extent of the seabed significantly affected by human activities for the different substrate types; (iii) presence of particularly sensitive and/or tolerant species; (iv) multi-metric indices assessing benthic community condition and functionality, such as species diversity and richness, proportion of opportunistic to sensitive species; (v) proportion of biomass or number of individuals in the macrobenthos above some specified length/size; and (vi) parameters describing the characteristics (shape, slope and intercept) of the size spectrum of the benthic community.

Jarvinen M.,Finnish Environment Institute | Drakare S.,Swedish University of Agricultural Sciences | Free G.,U.S. Environmental Protection Agency | Lyche-Solheim A.,Norwegian Institute for Water Research | And 9 more authors.
Hydrobiologia | Year: 2013

Phytoplankton data from 606 lakes were used to characterize indicator taxa of near-pristine reference conditions in clearwater and humic lowland lakes of Northern and Central Europe. Reference lakes were selected based on low pressure from catchment land-use, low population density and the absence of point sources. Reference lakes had low phytoplankton biomass and taxa richness compared to non-reference lakes. In low alkalinity lakes of Northern Europe, the reference communities had high biomass proportions of chrysophytes and low proportions of cyanobacteria; in the Central European high alkalinity lakes, the biomass was distributed more evenly among algal groups. Indicator species analysis and similarity analysis listed 5-29 taxa indicating reference conditions. Indicator taxa differed especially between the low alkalinity and the high alkalinity lakes, but there were also country-specific differences. Most common indicator taxa for the northern reference lakes were chrysophytes (e. g. Bitrichia, Dinobryon). In the Central European reference lakes, diatoms (e. g. Cyclotella) were more characteristic. Despite the differences, there was a general finding that taxa present in reference lakes were often also present in non-reference lakes, but typically in lower biomass proportions; another characteristic of the reference communities is the absence of many taxa typically found in non-reference lakes. © 2012 Springer Science+Business Media B.V.

Van Der Veeren R.,Rijkswaterstaat Center for Water Management
Water Policy | Year: 2010

Since 2005, several cost benefit analyses have been performed for the European Water Framework Directive (WFD) in The Netherlands. These analyses had in common that they were meant to support the decision-making process by informing policy makers and making the trade-offs as transparent as possible. The analyses also anticipate questions from the Dutch Parliament. Nevertheless, each time the analyses were slightly different, depending on the situation and (political) questions that had to be answered. This article presents the background and the highlights of the various analyses, describes their differences and similarities and tries to find a common thread in the results. Even though the results are barely comparable for a number of reasons, they seem to indicate that such a line exists and that economic analyses have played a role in the decision-making process by making tradeoffs more explicit. This has offered the opportunity for an iterative dialogue with the Dutch Parliament, which contributed to a decision-making process which resulted in a socially accepted programme of measures that is economically sound and transparent. © IWA Publishing 2010.

Sloff K.,Technical University of Delft | Van Spijk A.,Water management | Stouthamer E.,University Utrecht | Sieben A.,Rijkswaterstaat Center for Water Management
International Journal of Sediment Research | Year: 2013

In the Rhine-Meuse delta in the south-western part of the Netherlands, the morphology of the river branches is highly dependent on the erodibility of the subsoil. Erosion processes that were initiated after closure of the Haringvliet estuary branch by a dam (in 1970), caused a strong incision of several connecting branches. Due to the geological evolution of this area the lithology of the subsoil shows large variations in highly erodible sand and poorly erodible peat and clay layers. This study shows how the geological information can be used to create 3D maps of the erodibility of the sub-soil, and how this information can be used to schematize the sub-soil in computational models for morphological simulations. Local incisement of sand patches between areas with poorly erodible bed causes deep scour holes, hence increasing the risk on river-bank instability (flow slides) and damage to constructions such as groynes, quays, tunnels, and pipelines. Various types of mathematical models, ranging from 1D (SOBEK) to quasi-3D (Delft3D) have been applied to study the future development of the river bed and possible management options. The results of these approaches demonstrate that models require inclusion of a layer-bookkeeping approach for sub-soil schematization, non-uniform sediment fractions (sand-mud), tidal and river-discharge boundary conditions, and capacity-reduction transport modeling. For risk-reducing river management it has been shown how the development of the river bed can be addressed on a large scale and small scale. For instance, the use of sediment feeding and fixation of bed can be proposed for large-scale management, while monitoring and interventions at initiation of erosion can be proposed as response to small-scale developments that exceed predefined intervention levels. © 2013 International Research and Training Centre on Erosion and Sedimentation and the World Association for Sedimentation and Erosion Research.

Buschman F.A.,University Utrecht | Buschman F.A.,Rijkswaterstaat Center for Water Management | Van Der Vegt M.,University Utrecht | Hoitink A.J.F.,University Utrecht | And 2 more authors.
Journal of Geophysical Research: Oceans | Year: 2013

Tidal junctions play a crucial role in the transport of water, salt, and sediment through a delta distributary network. Water, salt and sediment are exchanged at tidal junctions, thereby influencing the transports in the connecting branches and the overall dynamics of the system. This paper presents observations of water, salt and sediment transports in three channels that connect at a stratified tidal junction. Flow variation in one channel was found to lag behind flow variation in a connected channel by more than 1 h, which is largely attributed to channel length differences from the junction to the sea. The water columns in the three channels were periodically stratified during spring tide, whereas the salinity structure represented a salt wedge during neap tide. Salinity differences between the three channels were substantial. The channels contain water bodies of different salinity and act largely independently. Flow velocities in the upper and lower layers differed substantially. Flow in the lower layer was generally in the direction of acceleration produced by the baroclinic pressure gradient. Interestingly, baroclinic pressure gradients were sometimes directed landward, indicating the presence of saltier water at the land side of the estuary. In sharp channel bends close to the junction, secondary flow was strongest at the highest axial flow velocity during spring tide. In one channel bend, these circulations steered the suspended sediment toward the inner bend, which affected the suspended sediment division. © 2013. American Geophysical Union. All Rights Reserved.

Beckers J.V.L.,Deltares | De Bruijn K.M.,Deltares | Riedstra D.,Rijkswaterstaat Center for Water Management
IAHS-AISH Publication | Year: 2013

The Dutch flood protection standards originate from the 1960s. As a result of economic growth and increase of the population over the past decades, these standards have possibly become insufficient to achieve the desired level of safety. Moreover, the EU Floods Directive requires each Member State to evaluate and reduce the flood risk. In line with this Directive, a risk-based approach for flood protection is being developed in the Netherlands, with safety standards that are based on both economic cost-benefit and life safety criteria. In order to support this new policy, a probabilistic risk assessment was performed for the main levee systems. This paper focuses on the life safety aspect. Two loss-of-life risk indicators are considered: the individual risk and the societal risk. These indicators give insight to, respectively, the most hazardous locations and the probability of a given number of fatalities during a single flood event. © 2013 IAHS Press.

Sieben J.,Rijkswaterstaat Center for Water Management | Talmon A.M.,Technical University of Delft | Talmon A.M.,Deltares
Journal of Hydraulic Research | Year: 2011

In rivers, dune crest patterns are not always perpendicular to the main flow direction, because deviations up to around 20° have been observed. These can affect the direction of sediment transport, but the available predictors for models do not account for this effect. Therefore, laboratory tests on sediment transport over artificial dunes oblique to the flow direction were conducted. The largest effect is due to helical flow at the lee side of a dune and from flow near the reattachment point. These three-dimensional features are lumped into a preliminary predictor to account for the direction of bed-load in models for two-dimensional river morphology with depth-averaged flow. To include dynamic bed-form orientation, an additional model for bed-form orientation is proposed. These concepts require further validation with mobile-bed observations and subsequent tests with numerical simulations. © 2011 International Association for Hydro-Environment Engineering and Research.

Loading Rijkswaterstaat Center for Water Management collaborators
Loading Rijkswaterstaat Center for Water Management collaborators