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- van Emmerik, T. (author), Schwarz, A. (author) article 2019
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Witte, J.P.M. (author), Zaadnoordijk, W.J. (author), Buyse, J.J. (author)Since the nineteen fifties, groundwater levels in the Netherlands dropped more than as simulated by hydrological models. In the rural sandy part of the Netherlands, the difference amounts to approximately 0.3 m on average. The answer to the question of what or who caused this 'background decline' of groundwater tables may have juridical and...article 2019
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Naus, F.L. (author), Schot, P. (author), Ahmed, K.M. (author), Griffioen, J. (author)In southwestern Bangladesh, the large variation in groundwater salinity has only been elucidated in small-scale study areas and along large regional-scale gradients. We aimed to assess the regional shallow (article 2019
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Saaltink, R.M. (author), Dekker, S.C. (author), Griffioen, J. (author), Wassen, M.J. (author)Understanding how the hydrological regime in relation to sediment type interferes with ecosystem development is important when wetlands are created with soft muddy material. Especially when plants are used as ecological engineers to promote crest stability and soil formation. We carried out a two-year mesocosm experiment with sediments derived...article 2018
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Pearce, C. (author), Cremer, H. (author), Lammertsma, E. (author), Wagner-Cremer, F. (author)Analysis of siliceous microfossils of a 79 cm long peat sediment core from Highlands Hammock State Park, Florida, revealed distinct changes in the local hydrology during the past 2,500 years. The coring site is a seasonally inundated forest where water availability is directly influenced by precipitation. Diatoms, chrysophyte statospores, sponge...article 2013
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Lammers, J.M. (author), van Soelen, E.E. (author), Donders, T.H. (author), Wagner-Cremer, F. (author), Damsté, J.S.S. (author), Reichart, G.J. (author)Assessing the impact of climate change and anthropogenic activity on Florida coastal areas requires a thorough understanding of natural climate variability. The available instrumental record, however, is too short and too limited to capture the full range of natural variability. In order to provide additional data on the natural state of the...article 2013
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van Geer, F. (author), Rozemeijer, J. (author), van der Velde, Y. (author), Broers, H.P. (author), de Rooij, G. (author)As part of two PhD projects, we installed ion-selective electrodes and passive samplers for monitoring nitrate concentrations in a 7 km 2 catchment and compared the results to grab samples. We also monitored nitrate concentrations at the catchment outlet. We tested the effectiveness of these monitoring approaches to estimate the long-term...conference paper 2011
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Visser, A. (author), Schaap, J.D. (author), Broers, H.P. (author), Bierkens, M.F.P. (author), TNO Bouw en Ondergrond (author)The production of N2 gas by denitrification may lead to the appearance of a gas phase below the water table prohibiting the conservative transport of tracer gases required for groundwater dating. We used a two-phase flow and transport model (STOMP) to study the reliability of 3H/3He, CFCs and SF6 as groundwater age tracers under agricultural...article 2009
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Crushell, P.H. (author), Smolders, A.J.P. (author), Schouten, M.G.C. (author), Roelofs, J.G.M. (author), van Wirdum, G. (author), TNO Bouw en Ondergrond (author)The peat and pore-water biogeochemistry of an Irish oceanic raised bog are reported with a view to understanding the origin and development of a minerotrophic soak contained within an ombrotrophic bog. Depth profiles of electrical conductivity, pore-water chemistry and peat chemistry were recorded from the mire surface down to a maximum depth of...article 2009
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Visser, A. (author), Schaap, J.D. (author), Leijnse, T. (author), Broers, H.P. (author), Bierkens, M.F.P. (author), TNO Bouw en Ondergrond (author)Degassing of groundwater by excess denitrification of agricultural pollution complicates the interpretation of 3H/3He data and hinders the estimation of travel times in nitrate pollution studies. In this study we used a two-phase flow and transport model (STOMP) to evaluate the method presented by Visser (2007a) to interpret degassed 3H/ 3He...conference paper 2008
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Slob, E. (author), Lambot, S. (author), Rhebergen, J.B. (author), Lopera, O. (author), Vereecken, H. (author), TNO Defensie en Veiligheid (author)A closed loop hydrogeophysical inversion procedure has been developed and tested in an outdoor test site facility to investigate its effectiveness in reconstructing hydraulic properties of a sandy soil under controlled conditions. We use global optimization followed by a local routine, which involves a large number of forward models to be...conference paper 2008
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Brink, C.v.d. (author), Zaadnoordijk, W.J. (author), Burgers, S. (author), Griffioen, J. (author), TNO Bouw en Ondergrond (author)Groundwater quality management relies more and more on models in recent years. These models are used to predict the risk of groundwater contamination for various land uses. This paper presents an assessment of uncertainties and sensitivities to input parameters for a regional model. The model had been set up to improve and facilitate the...article 2008
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van der Grift, B. (author), Griffioen, J. (author), TNO Bouw en Ondergrond (author)Historic emissions from ore smelters typically cause regional soil contamination. We developed a modelling approach to assess the impact of such contamination on groundwater and surface water load, coupling unsaturated zone leaching modelling with 3D groundwater transport modelling. Both historic and predictive modelling were performed, using a...article 2008
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Noomen, M. (author), Bremmer, C. (author), Vermooten, S. (author), Kukuric, N. (author), van Beek, R. (author), TNO Bouw en Ondergrond (author)This paper describes the initial stage of the assimilation of GRACE and ERS-1 and ERS-2 imagery with a global hydrological model. The outcome of the model will be evaluated with groundwater storage estimates based on GRACE data as well as with soil moisture estimates based on ERS-1 and ERS-2 scatterometer data.conference paper 2007
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van Geer, F. (author), Marsman, A. (author), Janssen, G.M.C.M. (author), TNO Bouw en Ondergrond (author)Usually the design of the monitoring system is based on the relation between the monitoring effort and the uncertainty of the information. Often the estimation error standard deviation is used as a criterion for the design. Despite the fact that, for scientists, the standard deviation as a measure of uncertainty is a logical criterion, water...conference paper 2007
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Schuurmans, J.M. (author), Bierkens, M.F.P. (author), TNO Bouw en Ondergrond (author)We investigate the effect of spatial variability of daily rainfall on soil moisture, groundwater level and discharge using a physically-based, fully-distributed hydrological model. We focus on the effect of rainfall spatial variability on day-to-day variability of the interior catchment response, as well as on its effect on the general...article 2006
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Valstar, J.R. (author), McLaughlin, D.B. (author), te Stroet, C.B.M. (author), van Geer, F.C. (author)Groundwater inverse problems are concerned with the estimation of uncertain model parameters, such as hydraulic conductivity, from field or laboratory measurements. In practice, model and measurement errors compromise the ability of inverse procedures to provide accurate results. It is important to account for such errors in order to determine...article 2004
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Vermeulen, P.T.M. (author), Heemink, A.W. (author), te Stroet, C.B.M. (author)Numerical models are often used for simulating groundwater flow. Written in state-space form, the dimension of these models is of the order of the number of grid cells used and can be very high (more than a million). As a result, these models are computationally very demanding, especially if many different scenarios have to be simulated. In this...article 2004
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Broers, H.P. (author), van der Grift, B. (author), Nederlands Instituut voor Toegepaste Geowetenschappen TNO (author)Changes in agricultural practices are expected to affect groundwater quality by changing the loads of nutrients and salts in recharging groundwater, but regional monitoring networks installed to register the changes often fail to detect them and interpretation of trend analysis results is difficult. This study aims to improve the detection and...article 2004
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Berendrecht, W.L. (author), Heemink, A.W. (author), van Geer, F.C. (author), Gehrels, J.C. (author), Nederlands Instituut voor Toegepaste Geowetenschappen TNO (author)A nonlinear state-space model is developed for describing water table fluctuations in groundwater systems that are influenced by drains. As drains are only active if the water table is above drainage level, the regime of the system switches at the drainage level. The water table depth is related to observations on precipitation and...article 2004
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