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Influence of HCl/HF treatment on organic matter in aquifer sediments : a Rock-Eval pyrolysis study
Rock–Eval pyrolysis is increasingly used for the routine characterization of natural organic matter in soils and sediments. In this work the bulk composition of sedimentary organic matter (SOM) in sandy aquifer sediments is studied, as well as purified samples (isolation of SOM) by HCl/HF treatment. This treatment is necessary to avoid detection limit problems for samples with low SOM contents, but the results presented here indicate that this treatment influences the organic geochemistry of the aquifer sediment samples.
Geochemical controls on sediment reactivity and buffering processes in a heterogeneous aquifer
In this study, the heterogeneity of the reductive capacity of an aquifer selected for water reuse projects was characterised, the amount, type and reactivity of the sedimentary reductants present determined, and the relationship between reductive capacity and sedimentary lithologies quantified. The average potential reductive capacities (PRCTOT), based on total organic C and pyrite concentrations of the sediment, were quantified for sands, clays and silts. Twenty-seven samples, spanning the three different lithologies, were then incubated for 50 days and the measured reductive capacities (MRC) determined for the sands, silts and clays.
Oppervlaktewater in Limburg sterk beïnvloed door grondwater
Inzicht in de invloed van grondwater onder verschillende afvoeromstandigheden op de oppervlaktewaterkwaliteit helpt bij vragen vanuit het GGOR- en KRW-proces en bij de afweging van de te nemen maatregelen. Maatregelen zoals grondwaterpeilveranderingen, drainage en mestmaatregelen kunnen beter worden beoordeeld op hun effect op de belasting van het gronden oppervlaktewater. Door middel van een door Deltares ontwikkelde methode is het mogelijk om een eerste beeld te krijgen van de relatie tussen grond- en oppervlaktewater en de grondwaterbijdrage aan het oppervlaktewatersysteem te kwantificeren op basis van aannames en een conceptueel model van de werking van het systeem. In het project Waterkwaliteit op basis van Afkomst en HYDrologische systeemanalyse (WAHYD) is deze methode in Limburg toegepast. De studie ondersteunt de notie dat de oppervlaktewaterkwaliteit voor een aantal stoffen sterk wordt beïnvloed door de grondwaterkwaliteit.
Impact of dredging and dumping on the stability of ebb-flood channel systems
The impact of dredging and dumping on the morphologic stability of the tidal channels is investigated using morphologic field observations for the Westerschelde estuary dating back to 1955. The results are used to verify the theoretical concept presented by Wang and Winterwerp (2001). This concept states that a critical threshold for the amount of sediment dumping exists above which a channel system in equilibrium may become unstable and degenerate.
Backfill grouting research at Groene Hart Tunnel
Measurements on back-fill grouting at Groene Hart Tunnel (GHT) are described and analysed.
Modelling of Singapore's coastal waters
Being between the two large water bodies the Andaman Sea in the west and the South China Sea in the east, the Singapore Strait's hydrodynamics are highly complex. An accurate hydrodynamic model is essential for a complete understanding of the flow pattern in the area. Using the Delft3D modelling system, the so-called Singapore Regional Model was developed to simulate tidal and wind-driven flows for the whole water body.
Sea level anomalies from satellite altimetry : retrieval and validation
This paper discusses techniques to extract tidal constants and sea level anomaly signatures from a variety of altimeter sensors, for a case study in a wide area around Singapore. As a next step, to determine how good (and useful) the results of these techniques are for subsequent data analysis and combination with models through data assimilation, validation studies were carried out on the consistency of the results of different altimeters and by comparing these with in-situ measurements.
On the dynamics of mud deposits in coastal areas
Introduction to the Proceedings of the International symposium on mud deposit in coastal areas (Porto Alegre, Brazil, 13-17 November 2006).
Wave modelling in a tidal inlet : performance of SWAN in the Wadden Sea
The performance of the spectral wave model SWAN for application in a tidal inlet system has been assessed through hindcasts of storm evens. Over the last five years wave measurements have been carried out i the tidal inlet of AMeland, which is part of the Dutch Wadden Sea. Measurements during three severe storms in 2007 have been used here to asses SWAN's performance in the Wadden Sea.
Morphological stability of tidal inlets using process-based modelling
Intl. Conf. on Coastal Engineering (ICCE), Hamburg, Germany.