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Life Cycle Analysis for four different ground improvement techniques
BioGrout is a method developed by SmartSoils Deltares to strengthen soil. It is based on Microbial In situ Calcite Precipitation (MICP). BioGrout 1st generation, using the ureaseenzyme, was developed in 2004. In 2008 the development of 2nd generation BioGrout, based on denitrification, was started. A Life Cycle Analysis (LCA) of the two BioGrout methods was produced, in order to determine their environmental impact and to investigate which steps in the process have the highest impact and should be improved. Also an LCA is made of two traditional ground improvement techniques (gel injection and jet grouting) in order to compare the two new methods with the traditional methods.
Tools for medium- and long-term prediction of nourishments effects
In this study the effect of different nourishment designs at the medium- (years, kilometres) and large- (decades to centuries, tens to hundreds of kilometres) scale was investigated by means of numerical tools and data analysis. The effects were evaluated by looking at a number of morphological indicators of simple use for coastal managers: the MKL position, the dune foot position and the beach width.
Stabilization of peat by infiltration of reactants - a feasibility study : infiltration of silica biopolymer suspension in peat
Assessment Zealand water level measurement network : creating a method for evaluating measurement networks using hydrodynamic models
There is an increasing demand for information on the state of water systems. A procedure was developed for optimizing a monitoring system that is based on data model integration (DMI) techniques. Using the optimisation procedure, a set of twelve measurement stations was expected to produce a DMI based monitoring system that satisfied an accuracy of RMSE of 3 to 5 cm at the Dutch stations.
Modelling the carrying capacity of the Oosterschelde : Deltakennis 2010
The integrated ecosystem model for the Oosterschelde has improved in several ways. As a result, modelled primary productions now show an acceptable fit with measurements. In comparison to previous results, however, the fit with measured nutrient and chlorophyll concentrations has somewhat deteriorated. Also, results suggest that the existing grazer pressure in the Oosterschelde may be larger than was predicted before.
Kustlijnzorg project : statistical modelling of the impact of nourishments on the beach and dune systems
A stochastic model has been developed, based on the historical trend analysis of long-term yearlyrecordedJarkus-data, in order to describe the long-term dynamics of Coastal State Indicators (e.g. MCLposition). The model includes mathematical representations of the most relevant phenomena: long-termtrend, influence of nearshore bar dynamics and impact of nourishments.
Estimation of predictive hydrologic uncertainty using the quantile regression and UNEEC methods and their comparison on contrasting catchments
This paper focuses on the methods predicting model residual uncertainty that differ in methodological complexity: quantile regression (QR) and UNcertainty Estimation based on local Errors and Clustering (UNEEC). The comparison of the methods is aimed at investigating how well a simpler method using fewer input data performs over a more complex method with more predictors. The authors test these two methods on several catchments from the UK that vary in hydrological characteristics and the models used.
ENSO-conditioned weather resampling method for seasonal ensemble streamflow prediction
Oceanic–atmospheric climate modes, such as El Niño–Southern Oscillation (ENSO), are known to affect the local streamflow regime in many rivers around the world. A new method is proposed to incorporate climate mode information into the well-known ensemble streamflow prediction (ESP) method for seasonal forecasting. The ESP is conditioned on an ENSO index in two steps. First, a number of original historical ESP traces are selected based on similarity between the index value in the historical year and the index value at the time of forecast. In the second step, additional ensemble traces are generated by a stochastic ENSO-conditioned weather resampler. These resampled traces compensate for the reduction of ensemble size in the first step and prevent degradation of skill at forecasting stations that are less affected by ENSO. The skill of the ENSO-conditioned ESP is evaluated over 50 years of seasonal hindcasts of streamflows at three test stations in the Columbia River basin in the US Pacific Northwest. An improvement in forecast skill of 5 to 10% is found for two test stations. The streamflows at the third station are less affected by ENSO and no change in forecast skill is found here.
Simulation studies for storm winds, flow fields and wave climate in the Wadden Sea
The motivation for this study is to assess the possibility of using wind, current and water level fields as simply as possible for the determination of the Hydraulic Boundary Conditions (HBC) in the Wadden Sea. Since storms are intrinsically unsteady processes, the purpose of this study is to investigate physically-based methodologies to simplify the wind fields that generate severe surges and use then as realistic forcing on the water in the Wadden Sea. An additional purpose is to perform a sensitivity analysis to various model settings for the determination of the wave conditions in the eastern Wadden Sea.
The reset of a subtidal bar during an energetic event : application to Le Truc Vert beach case (France)
A large number of beach morphologies across the world exhibits nearshore sandbars with complex 3D patterns. During large storms, these shapes disappear and the bars get to a certain extent alongshore uniform. This phenomenon is called a reset. Numerous studies have been conducted on the development of the bar shapes (3D) or on the cross-shore migration of sandbars (2D). The present work attends to determine the relevant processes involved in the reset of the three dimensional bars and to describe the relative influence of each of these processes. To perform this study, data collected during the ECORS campaign at Le Truc Vert (France) in 2008 are analysed. In addition, a numerical approach is performed using a new research Delft3D model forced by the Xbeach wave generator to investigate the processes involved in a reset-event. The effects of the hydrodynamic external conditions on the currents in the surfzone are investigated. Then the reset is studied in details in order to understand the role of the different processes taken into account by the numerical model. The significant role of the longshore currents induced by oblique wave incidence is clearly assessed. In addition, the long wave orbital velocities as well as the mean flow related to the short wave forcing control the stirring of sediments and influence the time scale of the reset-event.