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Assessments of phytoplankton in the Netherlands and neighbouring countries according to OSPAR and WFD
After the implementation of the European Water Framework Directive (EC-WFD, 2000), which was limited to the coastal waters and did not apply to all marine waters, the European Marine Strategy Framework Directive (MSFD) has been adopted in 2008 to protect the marine environment and its ecosystems, and to promote its sustainable use. The MSFD has been anchored into Dutch legislation in 2010. The objective of the MSFD (EC-MSFD, 2008) is to achieve and / or maintain good environmental status in European marine waters. The MSFD requires the Member States to take the necessary measures to achieve this goal in 2020. In the MSFD eleven descriptors have been defined, which are relevant for the implementation of the directive. The descriptor of concern in this report is descriptor 5 for eutrophication, which states: “Human-induced eutrophication is minimised, especially adverse effects thereof, such as losses in biodiversity, ecosystem degradation, harmful algae blooms and oxygen deficiency in bottom waters” (EC-MFSD, 2008). The European Commission is directing the process, but the individual Member States are responsible for the implementation of the MSFD and the cooperation and international coordination within a marine (sub)region. Member states shall, as far as possible, build upon relevant existing programmes and activities developed in the framework of international agreements such as Regional Sea Conventions. In the OSPAR convention eutrophication is one of the points of concern. OSPAR developed the Comprehensive Procedure, which is a harmonized, integral assessment system of the main causes and effects of eutrophication. The OSPAR Common Procedure is ‘fit for the purpose’ of assessing this descriptor and supports the setting of targets and indicators under MSFD (OSPAR, 2012a; OSPAR 2012b). As OSPAR is in force for the whole North-eastern Atlantic, while the WFD is for ecology only valid in marine waters in the zone within one nautical mile from the coast line (Figure 1.1), the comparability between OSPAR COMP and WFD needs attention. There are differences between OSPAR COMP and WFD assessments in the use of chlorophyll-a and Phaeocystis metrics, both in geographical extent and in the aggregation of the metrics into the final assessment. The objective of this report is to make an inventory, for chlorophyll-a and Phaeocystis, of the OSPAR Comprehensive Procedure and of the WFD assessment method and the results of both methods for the Netherlands and the North Sea countries: Belgium, Germany, UK and France. For the WFD Prins & Baretta-Bekker (2010) gave an overview of the scientific background of the Phaeocystis metric, as one of the indicators for eutrophication. It contains the various aspects of the methods from sampling to setting the class boundaries used by the Netherlands and the neighbouring countries. The present report expands on this paper by including the WFD metric for chlorophyll in order to account for the other phytoplankton component.
Tourist' valuation of climate change impacts on the Dutch Wadden Sea : a travel cost method and choice experiment
This study aims to estimate tourists' willingness to pay for changes in marine ecosystems due to several climate induced effects on the marine environment. The results can be used for the development of marine and coastal policy in the Wadden Sea as well as for climate change policy.
Opzet landelijk meetnet gewasbeschermingsmiddelen land- en tuinbouw
Een van de maatregelen uit de 2e Nota Duurzame Gewasbescherming (2013-2023) is het gebruik van monitoringgegevens van gewasbeschermingsmiddelen (GSM) in oppervlaktewater, om oorzaken van normoverschrijding aan te kunnen wijzen. Het doel is het aantal normoverschrijdingen de komende 10 jaar met 90% te verminderen. Om dit doel te faciliteren is besloten voor deze GSM-monitoring een landelijk meetnet in te stellen, waarmee in de periode van 2014 tot 2023, elk jaar op vaste locaties met een vaste meetstrategie zal worden gemeten. Het meetnet beoogt 1) het zo optimaal mogelijk leggen van een aannemelijk verband tussen de toepassing van GSM en de waargenomen normoverschrijdingen in oppervlaktewater en 2) het trendmatig volgen van de voortgang in de reductie van normoverschrijdingen van toegelaten GSM in het oppervlaktewater. Dit rapport bevat de opzet voor dit landelijk meetnet voor GSM. In samenspraak met de waterschappen zijn bij diverse teelten meetpunten geselecteerd die geschikt zijn voor het landelijk meetnet. Tevens is aangegeven welke stoffen bij voorkeur op grond van de toelating en teelten gemeten moeten worden, met daarbij de geadviseerde monitoringsfrequentie.
Stabiliteitsformules voor ingegoten steenzettingen
In dit rapport is het huidige rekenmodel dat Steentoets (Steentoets2010 versie 1.11, Deltares, februari 2013) gebruikt voor het berekenen van de stabiliteit van ingegoten steenzettingen omgewerkt tot een nieuw rekenmodel.
Zur Ermittlung von Grundwasserständen für Karten zur Gefährdung des Grundwasseranstiegs infolge eines Hochwassers
Modelling gravel barrier profile response to combined waves and tides using XBeach : laboratory and field results
This paper uses results obtained from the large-scale BARDEX experiments undertaken in the Delta flume to investigate the morphological response of a prototype gravel barrier to wave and tidal forcing during overwash conditions. Gravel barrier behaviour depends upon a number of factors such as sediment properties (porosity, permeability, grainsize), geological setting and wave climate.
Isotopic and microbiological signatures of pyrite-driven denitrification in a sandy aquifer
The groundwater and sediment composition along a redox gradient in a nitrate-polluted pyritic sandy aquifer in Oostrum (the Netherlands) was studied to identify the sequence of steps involved in denitrification coupled to pyrite oxidation.
Model experiments on geosynthetic reinforced piled embankments : 3D test series
In the Netherlands, several field measurements were carried out in piled embankments with a geosynthetic basal reinforcement (GR). This paper presents a series of nineteen 3D model experiments on piled embankments. Purpose of the tests was to find an explanation why the calculated GR strains exceed the GR strains measured in the field.This paper focuses on the starting points of the test series, the test set-up and the scaling rules and gives a summary of the results. Van Eekelen et al., (2011b and 2011c) describe the results of the tests extensively.Five starting points were leading to the development of the test set-up. (1) Possibility to evaluate the two calculation steps separately, (2) Possibility to evaluate the influence of consolidation of the subsoil, (3) Inclusion of GR, (4), Modelling the fill realistically, (5) a realistic stress level and scale.For the test conditions (static load, laboratory scale), it was found that consolidation of the subsoil results in an increase of arching. This is not in agreement with the current calculation models. Loading on the GRis concentrated on the strips lying above and between adjacent piles (the "GR strips") which is in agreement with the current calculation models. The measured load on a GR strip has the distribution of aninverse triangle, although the load may be even more concentrated around the pile caps than this indicates.This is not in agreement with the current calculation models. Implementing this in the CUR/EBGEO calculation model results in 19-26% less GR strain.
Mathematical model and analytical solution for the fixation of bacteria in biogrout
Biogrout is a new method for soil reinforcement. Bacteria and reactants are flushed through the soil, resulting in calcium carbonate precipitation and consequent soil reinforcement. Bacteria are crucially important in the Biogrout process since they catalyse the reaction. In this article, a model is derived for the placement of bacteria. An analytical solution is derived for instantaneous reactions. The analytical solution iscompared to numerical simulations for finite reaction rates.
State updating of a distributed hydrological model with Ensemble Kalman Filtering : effects of updating frequency and observation network density on forecasts accuracy
This paper presents a study on the optimal setup for discharge assimilation within a spatially distributed hydrological model. The Ensemble Kalman filter (EnKF) is employed to update the grid-based distributed states of such an hourly spatially distributed version of the HBV-96 model. By using a physically based model for the routing, the time delay and attenuation are modelled more realistically. The discharge and states at a given time step are assumed to be dependent on the previous time step only (Markov property). Synthetic and real world experiments are carried out for the Upper Ourthe (1600 km2), a relatively quickly responding catchment in the Belgian Ardennes.We assess the impact on the forecasted discharge of (1) various sets of the spatially distributed discharge gauges and (2) the filtering frequency. The results show that the hydrological forecast at the catchment outlet is improved by assimilating interior gauges. This augmentation of the observation vector improves the forecast more than increasing the updating frequency. In terms of the model states, the EnKF procedure is found to mainly change the pdfs of the two routing model storages, even when the uncertainty in the discharge simulations is smaller than the defined observation uncertainty.