Searched for: author%3A%22Bakker%2C+M.%22
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Collenteur, Raoul A. (author), Bakker, M. (author), Klammler, Gernot (author), Birk, Steffen (author)
The estimation of groundwater recharge is of paramount importance to assess the sustainability of groundwater use in aquifers around the world. Estimation of the recharge flux, however, remains notoriously difficult. In this study the application of nonlinear transfer function noise (TFN) models using impulse response functions is explored to...
journal article 2021
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Urgilez Vinueza, A.R. (author), Robles, Jessica (author), Bakker, M. (author), Guzman, Pablo (author), Bogaard, T.A. (author)
The high landslide risk potential along the steep hillslopes of the Eastern Andes in Ecuador provides challenges for hazard mitigation, especially in areas with hydropower dams and reservoirs. The objective of this study was to characterize, understand, and quantify the mechanisms driving the motions of the Guarumales landslide. This 1.5 km...
journal article 2020
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des Tombe, B.F. (author), Schilperoort, B. (author), Bakker, M. (author)
Distributed temperature sensing (DTS) systems can be used to estimate the temperature along optic fibers of several kilometers at a sub-meter interval. DTS systems function by shooting laser pulses through a fiber and measuring its backscatter intensity at two distinct wavelengths in the Raman spectrum. The scattering-loss coefficients for...
journal article 2020
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Bradley, C.E. (author), Randall, J.A.D. (author), Abobeih, M.H.M.A. (author), Berrevoets, R.C. (author), Degen, M.J. (author), Bakker, M. (author), Markham, M. (author), Twitchen, D. J. (author), Taminiau, T.H. (author)
Spins associated with single defects in solids provide promising qubits for quantum-information processing and quantum networks. Recent experiments have demonstrated long coherence times, high-fidelity operations, and long-range entanglement. However, control has so far been limited to a few qubits, with entangled states of three spins...
journal article 2019
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Obergfell, C.C.A. (author), Bakker, M. (author), Maas, C. (author)
A new method is presented to estimate average diffuse aquifer recharge of water table aquifers in temperate climates using time series analysis of water table level fluctuations. An accurate estimate of the recharge caused by rainfall requires an accurate estimate of the influence of evaporation. In temperate climates, evaporation imprints a...
journal article 2019
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Collenteur, R.A. (author), Bakker, M. (author), Caljé, Ruben (author), Klop, Stijn A. (author), Schaars, Frans (author)
Time series analysis is an increasingly popular method to analyze heads measured in an observation well. Common applications include the quantification of the effect of different stresses (rainfall, pumping, etc.), and the detection of trends and outliers. Pastas is a new and open source Python package for the analysis of hydrogeological time...
journal article 2019
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des Tombe, B.F. (author), Bakker, M. (author), Smits, F.J.C. (author), Schaars, Frans (author), van der Made, Kees Jan (author)
An approach is presented to determine groundwater flow in unconsolidated aquifers with a heat pulse response test using a heating cable and a fiber-optic cable. The cables are installed together using direct push so that the cables are in direct contact with the aquifer. The temperature response is measured for multiple days along the fiber...
journal article 2019
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Obergfell, C.C.A. (author), Bakker, M. (author), Maas, C. (author)
Time series analysis is applied to identify and analyze a transition in the groundwater regime in the aquifer below the sand ridge of Salland in the Netherlands, where groundwater regime refers to the range of head variations throughout the seasons. Standard time series analysis revealed a discrepancy between modeled and observed heads in...
journal article 2019
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Bakker, M. (author), Schaars, Frans (author)
Time series analysis is a data-driven approach to analyze time series of heads measured in an observation well. Time series models are commonly much simpler and give much better fits than regular groundwater models. Time series analysis with response functions gives insight into why heads vary, while such insight is difficult to gain with black...
journal article 2019
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Bakker, M. (author)
A new analytic solution is presented for tidal propagation in multilayer coastal aquifers consisting of an arbitrary number of layers. The solution is derived using matrix calculus and may be applied to simulate tidal propagation in systems where aquifer layers are separated by leaky layers of low permeability or in stratified aquifers. The head...
journal article 2019
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des Tombe, B.F. (author), Bakker, M. (author), Schaars, Frans (author), van der Made, Kees Jan (author)
An approach is presented to determine the seasonal variations in travel time in a bank filtration system using a passive heat tracer test. The temperature in the aquifer varies seasonally because of temperature variations of the infiltrating surface water and at the soil surface. Temperature was measured with distributed temperature sensing...
journal article 2018
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Post, Vincent E.A. (author), Essink, Gualbert Oude (author), Szymkiewicz, Adam (author), Bakker, M. (author), Houben, Georg (author), Custodio, Emilio (author), Voss, Clifford (author)
The Salt Water Intrusion Meetings, or SWIMs, are a series of meetings that focus on seawater intrusion in coastal aquifers and other salinisation processes. 2018 marks the 50th year of the SWIM and the 25th biennial meeting. The SWIM proceedings record half a century of research progress on site characterisation, geophysical and geochemical...
journal article 2018
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van der Spek, J.E. (author), Bakker, M. (author)
The influence of the length of the calibration period and observation frequency on the predictive uncertainty in time series modeling of groundwater dynamics is investigated. Studied series are from deltaic regions with predominantly shallow groundwater tables in a temperate maritime climate where heads vary due to precipitation and...
journal article 2017
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Bakker, M. (author), Miller, Anthony D. (author), Morgan, Leanne K. (author), Werner, Adrian D. (author)
A computational approach is presented for steady Dupuit interface flow where the aquifer extends below the sea. A detailed approach is outlined to determine the head at the coastline so that the solution below the leaky seabed may be combined with any type of steady Dupuit interface flow in the aquifer below the land. The method allows for...
journal article 2017
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Fienen, Michael N. (author), Bakker, M. (author)
In the past decade, difficulties encountered in reproducing the results of a cancer study at Duke University resulted in a scandal and an investigation which concluded that tools used for data management, analysis, and modeling were inappropriate for the documentation of the study, let alone the reproduction of the results. New protocols were...
journal article 2016
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Bakker, M. (author)
The loading efficiency (sometimes called the tidal efficiency) is often neglected when simulating the head response in an aquifer to water level changes in lakes and streams. This is not appropriate when the lake or stream only partially penetrates the aquifer. In such cases, the aquifer extends below the lake or stream and is hydraulically...
journal article 2016
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van Ginkel, M. (author), des Tombe, B.F. (author), Olsthoorn, T.N. (author), Bakker, M. (author)
Regular aquifer storage recovery, ASR, is often not feasible for small-scale storage in brackish or saline aquifers because fresh water floats to the top of the aquifer where it is unrecoverable. Flow barriers that partially penetrate a brackish or saline aquifer prevent a stored volume of fresh water from expanding sideways, thus increasing...
journal article 2016
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des Tombe, B.F. (author), Bakker, M. (author), Schaars, F (author), van der Made, KJ (author), Calje, R (author), Borst, L. (author)
Targeted provisional session N°8.01 The seasonal variation in residence times is determined in a managed aquifer recharge system using a passive heat tracer test. The managed aquifer recharge system consists of a sequence of alternating elongated recharge basins and rows of recovery wells. The temperature of both the water in the recharge basin...
abstract 2016
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Shao, W. (author), Bogaard, T.A. (author), Su, Y. (author), Bakker, M. (author)
In this study, a 1D hydro-mechanical model was developed by coupling a dual-permeability model with an infinite slope stability approach to investigate the influence of preferential flow on pressure propagation and slope stability. The dual-permeability model used two modified Darcy-Richards equations to simultaneously simulate the matrix flow...
journal article 2016
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Obergfell, C.C.A. (author), Bakker, M. (author), Maas, Kees (author)
The flood-wave method is implemented within the framework of time-series analysis to estimate aquifer parameters for use in a groundwater model. The resulting extended flood-wave method is applicable to situations where groundwater fluctuations are affected significantly by time-varying precipitation and evaporation. Response functions for time...
journal article 2016
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