Rapid discharge of excess water has always been the core of Dutch water management. Due to climate change, a change in strategy is required. A future-proof drainage strategy consists of three steps: 1) retention, 2) storage, and 3) controlled removal. This thesis comprises the design and evaluation of an algorithm for groundwater-based Model Predictive Control (MPC) of water table control systems in polder areas. The objective is to maximize retention of precipitation, thereby contributing to the first component of the new drainage strategy. The control algorithm is developed for water table control on a single plot surrounded by a ditch, and three variants of water table control systems are considered: 1) water table control without drains, 2) water table control with submerged drains, controlled by ditch water level, and 3) water table control with submerged drains, controlled by sump water level. As a first approach, a relatively high, fixed setpoint is applied to maximize retention of precipitation. The controller adjusts the crest level of a weir that manages the ditch or sump water level. The algorithm performance is assessed through model simulations for two case study areas with distinct geohydrological response times within the management area of Hoogheemraadschap van Rijnland: 1) Polder Het Langeveld, a sandy polder located in the Flower Bulb Region, and 2) Polder Vierambacht, a clayey polder located in the Green Heart. Groundwater-based MPC anticipates precipitation events. Since the forecast horizon for which accurate precipitation forecasts are available is restricted, the feasibility of groundwater-based MPC is dependent on the response time of the groundwater system. Systems with a fast groundwater response are not suitable for water retention, while proper groundwater table control is possible. Control of systems with long system response times is hard, but these systems are applicable for water storage. A trade-off between controllability and water storage should thus be made. For the applied weir settings and objective function, a system response time lower than 10 days is required for proper control. Direct control of groundwater levels could induce a certain groundwater storage or water retention, depending on the applied setpoint.

Underground thermal energy storage (UTES) is an efficient technique to fulfill the heating and cooling demand of buildings. UTES uses stable subsurface temperatures store and extract energy. This study covers two types of UTES systems: aquifer thermal energy systems (ATES) and borehole heat exchangers (BHE). UTES systems in the Netherlands have seen a significant growth over the past years (Bloemendal, 2018) and are expected to contribute up to 20% of the heating and cooling demand of buildings by 2050 (Naber et al., 2016). As more UTES systems are installed, the risk of unwanted interaction between different system increases. However, ATES-BHE interaction is largely unknown.
The objective of this study is to gather more insight in the interaction of ATES system on the efficiency of BHE systems. A numerical model is used to simulate an ATES well near a BHE system using SEAWAT (Langevin et al., 2008). The model is used to run different simulations, from which the efficiency of a BHE system is computed under different circumstances over a five year period. Four conclusions are drawn from the results. First, groundwater and temperature interference from ATES systems affect the efficiency of a BHE system differently. Simulations show that the effect of groundwater flow induced by an ATES system always has a positive effect on the efficiency of a BHE system. The effect of temperature interference is dependent on the temperature of the ATES well. Groundwater was also found to interfere at larger distances between both systems compared to temperature. Second, the degree of interference is related to the distance between the ATES and BHE system. For distances smaller than 0.5 times the thermal radius of the ATES system, interference from temperature was found to be dominant in the simulations. For distances larger than 0.5 times the thermal radius of the ATES system, groundwater interference was found to be the dominant factor. The third conclusion is that the depth placement of the ATES well screen has little to no effect on the amount of interference on the BHE system. Fourth, it is important to realize that no energy is spontaneously generated or lost as BHE efficiencies increase or decrease respectively. Energy is simply exchanged between the ATES and BHE system through the subsurface. Whether that is disadvantageous depends on the energy demands of both systems. Most energy demands are imbalanced, meaning either cooling or heating demand is larger than the other. It is recommended to consider UTES system installations from a holistic point of view.

The Maurikse Wetering is a tributary of the Line river in the centre of the Netherlands. As the catchment is situated between and in close proximity to the larger Nederrijn and Waal rivers, intercatchment groundwater flow (IGF; groundwater flow crossing topographic divides) might have a significant influence on the water balance of the Maurikse Wetering catchment. As the IGF cannot be measured directly and due to the complex nature of the IGF, the IGF is considered to be one of the hardest fluxes to quantify in conceptual hydrological modelling. The objective of this thesis is to express the IGF as a function of easy-to-measure variables.
The most common method used to estimate the net IGF to a catchment in conceptual hydrology is to equate the IGF to the missing water in the water balance of the catchment. A different approach is analyzed in this thesis. To quantify the IGF, the Maurikse Wetering catchment and the surrounding area is modelled in the groundwater model MORIA. The direction of the groundwater flow shows that the groundwater flow in the region is heavily influenced by the Nederrijn and Waal rivers. A multiple linear regression (MLR) analysis was performed to study the influence of variables affecting the water balance of the Maurikse Wetering, e.g. the water level in the Nederrijn, the groundwater level in the Maurikse Wetering catchment and the precipitation, on the IGF. The resulting relations reliably model the IGF. The fact that multiple easy-to-measure factors have a relation to the IGF, shows that there are alternative methods to equating the IGF to the missing water in the water balance. This provides a basis for the usage of IGF relations in predictive modelling.
To analyse the effect the IGF has on conceptual hydrological models, the catchment is modelled in WALRUS. The model is calibrated, modelled and validated both without IGF data and with the IGF as modelled by the derived relations. Including the IGF in WALRUS shows an improvement in modelling the variation in groundwater level over smaller time steps compared to the WALRUS model without IGF, the latter only showing a seasonal change in groundwater level. During validation, the model with the IGF relation retains a higher efficiency in modelling the average groundwater level in the Maurikse Wetering than the model without an IGF flux. The results with and without the incorporation of IGF into the model show that the IGF can contribute to significant improvements for conceptual hydrological models.

The thermal recovery efficiency of High Temperature Aquifer Thermal Energy Storage (HT-ATES) systems can be limited due to the effect of buoyancy flow of the injected hot water. This thesis has researched the application of a Multiple Partially Penetrating Wells (MPPWs) as a well design method to counteract the effect of buoyancy flow and improve the performance of HT-ATES systems (>60°C). A MPPW is a well with more than one screen that allows injection and extraction of water at different depths in the aquifer.This method to counteract the effect of buoyancy flow was tested through numerical modelling with SEAWATv4. The modelled HT-ATES systems were running for four recovery cycles each including injection-storage-extraction-rest phases. The thermal recovery efficiency was determined over these cycles for 7 different scenarios and four different cases: a) A regular HT-ATES system with a fully penetrating screen, b) a regular HT-ATES system where buoyancy flow is neglected, c) an HT-ATES system with a MPPW with two screens, d) an HT-ATES system with four screens. The latter case was tested for three different control approaches based on data from four different locations in the aquifer.For the reference scenario where 90°C water was injected, a regular HT-ATES system had a thermal recovery efficiency of 0.61. With the application of MPPWs for both two or four screens this was 0.81 in the fourth recovery cycle, which approaches the case without buoyancy which had a thermal recovery efficiency of 0.88. The application of two or four screens did not show significant difference in thermal recovery efficiency after the first recovery cycle.A sensitivity analysis showed that the absolute increase in thermal recovery efficiency of an HT-ATES system with a MPPW compared to a regular HT-ATES is higher for larger buoyancy flow (i.e, high injection temperature and high (vertical) hydraulic conductivity), smaller injection volume and larger aquifer thickness. An applicability analysis showed that application of MPPWs is beneficial if the buoyancy flow (which is defined as the vertical hydraulic conductivity times the density ratio of the ambient groundwater and injected water) is greater than 0.1 meters per day.

This thesis proposes an approach for tackling the problem of data-shortage in hydrological modelling. A hydrological model, in the context of this thesis, translates meteorological data to stream-flow of a river, for a specific catchment. A model incorporates parameters that describe the dynamics of a chosen model, in this case a FLEX (Flux-Exchange) based model. All parameter together form a set. These parameters are unknown and therefore need to be determined, which is done via a calibration process. In the calibration process, the modelled flow will be evaluated against the observed stream-flow over a period of time for a certain hydrological signature. A hydrological signature is defined as the quantification of specific information concerning the rainfall-runoff dynamics of a catchment, e.g. the mean stream-flow. The evaluation for a certain hydrological signature is known as an evaluation criterion. Literature deems the use of one or two criteria in combination with multiple years of data enough to ensure a good performance from the parameter-sets that exit the calibration process. As this amount of data is not available everywhere, this thesis proposes to still ensure good model performance for less observed data. For this purpose, a selection was made of evaluation criteria to be applied in the calibration process. These criteria were selected in such a way that various different characteristics of the hydrological response were covered. A benchmark was created for comparison purposes in which 10 years of data was used during calibration and one evaluation criterion. After the benchmark, the observed data was shortened and evaluation criteria were added. The results showed that 6 months worth of data in combination with all criteria would create benchmark-level performances without extra information. The same level of performance can be reached with 3 months of data but this would require extra information. This information would be e.g. during which period of time observed data should be collected.

Aquifer thermal energy storage (ATES) is a sustainable technology that provides thermal energy to buildings in temperate climates. The principle of ATES is to temporary store thermal energy in aquifers in a warm and cold well in order to use this thermal energy for heating and cooling in the next season. Because the available subsurface space is limited, congestion problems can occur in areas with high ATES density. In these areas a conflict of interests exists between private parties who want to achieve maximum efficiency by avoiding negative influence of other systems (leading to large buffers between wells), and the public interest to maximize the amount of thermal energy stored in the aquifer. One solution to this problem is to reduce the distance between wells of the same temperature, creating one large thermal zone around the wells. The main goal of this research is to quantify the change in performance of ATES systems when their thermal zones are connected. The results of this research are as follows. Connecting the thermal zones of wells of the same temperature increases the thermal recovery efficiency of individual systems. This increase is between 8-15% for an average ATES system with a storage volume of 250.000 m³. It is even higher for smaller systems, 15-40% for a system with a storage volume of 50.000 m³. This is crease in efficiency is due to lower losses to the surroundings due to a lower area of the thermal zone compared to the volume of the thermal zone. The reduced distance between wells leads to an increase in pumping energy. Therefore an optimal distance between wells of the same temperature of 0.5 times the thermal radius is found. The distance between wells of opposite temperature should be larger than 3 times the thermal radius.

In 2014, a project, Living Lab Land Subsidence, is established to find a sustainable solution for land subsidence problem in Gouda. Being a part of the project, this research focuses on building a high-resolution groundwater model (2m*2m) by describing the model (such as recharge, leaky sewerage pipes) in local details. Water management strategies can be tested in the model to observe their effects on the groundwater levels. Then this model can be linked to a land subsidence model for further study on land subsidence under different (ground)water management scenarios.

Tunnel construction projects in the western part of the Netherlands are typically built in soft, heterogeneous ground conditions with low stiffness and high groundwater tables. The tunnelling technique used is the ‘slurry shield’ method, which uses a tunnel-boring machine (TBM). The TBM consists of a steel cylinder with a cutting wheel at the front. At the face of the TBM, called bore front, a pressurised slurry is used as face support. The aim of a static tunnel face stability assessment is to determine the horizontal effective stress and pore water pressure acting at the tunnel face both during boring and a standstill. While the pore water pressure distribution along the tunnel is clear, the estimation of the horizontal effective stress distribution is difficult. At the moment many calculation models have been developed to calculate the latter, but none ever made it into a standard. The first part of this thesis consists of a comparative study between the Ruse-Vermeer (2002), Jancsecz-Steiner model (1984) and DIN4126+4085-model (2008). A theoretical background analysis has been performed for each model; by using a case study analysis, the effect of the models’ differences on the minimum support pressures has been determined. Thereafter, this theoretical analysis has shifted to a more ‘practical’ project analysis by including external aspects like project aspects, soil conditions and contract requirements. From the practical project analysis it resulted that at the entrance zones, the soil cover is limited and thus additional surcharge is required. The placement of this additional surcharge lead to consolidation in the subsoil which can subsequently influences the static face stability assessment. Within this research a model is proposed in order to incorporate a one-dimensional vertical consolidation analysis within face stability assessment. During tunnelling a continuous process of slurry penetration and excavation takes place and therefore, the interaction between the support fluid, advancement of the TBM and the soil needs to be taken into account. The combination of these two time-dependent effects can possibly lead to the build-up of excess pore pressures in front of the tunnel face which has a high influence on the minimum support pressure. The second part of this research investigates the possibility to include the time dependent effect of slurry infiltration and excavation within a face stability assessment e.g. transient face stability assessment. The last part of this research is based on the role of slurry TBM parameters on ground deformations. Due to overcutting and the tapered shape of the TBM, a joint (annulus) is present between the TBM and the soil formation. In this research it is assumed that the annulus is hydraulically connected to the face. This means that the annulus is pressurized with bentonite slurry originating from the face. Due to the slurry pressure gradient and hydraulic connection with the annulus, not at each location the exact geostatic stress can be reached and ground deformations will inevitably take place.

The industrial site of Vosdonk Noord at Etten-Leur in the Netherlands consists of a large soil contamination in combination with highly heterogenic shallow subsurface soil characteristics. In this report, we study the groundwater flow and solute transport behaviour at this project location. Throughout this process, knowledge is gathered about the interpretation of the shallow subsurface heterogeneity with a main focus on the hydraulic conductivities. It is interesting to look at the subsurface heterogeneity because of the challenge to implement it inside a model and its uncertainty in characteristics. This means the subsurface heterogeneity is part of the problem to be solved. A comparison of groundwater flow and solute transport results were made using kriging as an interpolation method to implement subsurface cone penetration test data directly into the model. This generated a cell by cell implementation of the subsurface characteristics. To include the possible variability of the subsurface and to increase the reliability of the results, random simulations were implemented. In practice, the “pancake” method characterises the subsurface in a commercial software like Visual Modflow. This “pancake” method uses continuous horizontal subsurface soil layers. The gathered knowledge is useful to try and tackle the in practice used “pancake” method in case of a highly heterogenic subsurface.

Sand replenishments, or nourishments, have been the prevalent strategy of the Netherlands for coastal protection since 1990. In consideration of the expected sea level rise and potential increases of storm surges as a result of climate change, an innovative pilot project known as the ‘Sand Engine’ has been implemented. In contrast with traditional replenishments that are repeated with 3 to 5 year intervals, this local mega-nourishment is expected to protect the coastline for a period of at least 20 years. As sand replenishments are a widely applied technique, the concept of the Sand Engine, if proven successful, could be an effective solution for other areas of the world as well. This study looks into the potential effects of a large-scale sand replenishment on fresh groundwater resources, on four coastal areas in different parts of the world where such a project could be applied. These effects were quantified using 2-D variable density groundwater flow and coupled salt transfer models, by simulating the fresh-saline water interface before and after the replenishment, and comparing the results based on the current sea level and weather conditions with those based on scenarios of climate change. The results show that a large sand replenishment can lead to a considerable increase in the fresh groundwater volume, offering an opportunity to combine coastal protection with an increase of freshwater availability for areas with limited water resources.