Le monde économique connaît actuellement un large mouvement de réglementation afin de stabiliser la finance et de renforcer la surveillance des activités bancaires à travers le nouveau dispositif de Bâle. Ce dernier est au centre du débat actuel sur les besoins de financement de l’économie dans le cadre de la crise actuelle et ses effets sur le financement de l’économie. En effet, les pays développés ont connu un credit crunch à la suite de la crise des subprimes et du renforcement de la réglementation des activités bancaires. Dans ce cadre, nous nous intéressons aux effets du nouveau cadre réglementaire et de son application dans les pays développés, où sont implantées les banques internationales, sur leurs flux bancaires vers les pays émergents qui ont déjà connu de grandes crises dues à la nature volatile de leur financement extérieur. Les résultats apportés dans le cadre de cette thèse montrent que la réglementation basée sur les pondérations aux risques affecte le volume, la structure et la volatilité de ces flux. En effet, vu l’importance des flux bancaires dans le financement des pays émergents et vu le renforcement des exigences réglementaires dans le contexte de la crise, la modification des possibilités d’arbitrage réglementaire a conduit à des modifications de la structure du financement externe des pays émergents avec la progression du financement obligataire au détriment du financement bancaire. Cette nouvelle structure, volatile et dépendant des cycles de marché, n’est pas sans conséquences sur la stabilité financière de ces pays trop sensible aux changements de financement externe, ce qui implique de nouveaux défis pour garantir la stabilité de ces pays émergents. / The economic world is now undergoing a large regulatory movement to stabilize finance and strengthen the supervision of banking activities through the new Basel agreement. This agreement is the focus of the current debate on the economy financing needs in the context of the recent crisis and its effects on the economy financing. Indeed, developed countries have recently experienced a credit crunch following the subprime crisis and strengthening the regulation of banking activities. In this context, we are interested in the effects of the new regulatory framework and its application in developed countries, where are headquarters of international banks, on their banking flows to emerging countries that have already experienced major crises due to the volatile nature of external financing. The results obtained in this thesis show that regulation based on risk weights affects the volume, structure and volatility of these flows. Indeed, given the importance of bank flows in the financing of emerging countries and given the strengthening of regulatory requirements in the context of the crisis, the change in regulatory arbitrage opportunities modifies the external financing structure of emerging countries with the evolution of bond financing instead of bank financing. This new external financing structure, volatile and depends on market cycles, is not without consequences for the financial stability of these countries, which remains very sensitive to changes in external financing, what implies new challenges to guarantee their stability.

This thesis presents three essays on the main determinants and regulations of international capital flows. The essays contribute to an ongoing significant debate among scholars and practitioners on what determines international capital flows by examining the following issues: Global liquidity, market sentiment and financial stability indices; Global liquidity and capital flow regulations; and Global governance and gross capital flows dynamics. In the first essay, we explore the main determinants of global liquidity, measured using cross-border claims of banks, and establish the link between a variety of financial stability indices and global liquidity. For a sample of 149 countries between 2000 and 2016, we find that Bloomberg Financial Stability Indices are more powerful in explaining global liquidity than FRED Financial Stress Indices and the Euro Area Systemic Stress Composite Indicator (CISS). Moreover, both market sentiment indices, namely the US Conference Board Leading Economic Index (LEI) and the US IBD/TIPP Economic Optimism Index are economically and statistically significant on cross-border bank flows. The research provides useful insights on what market sentiment and financial stability indices are better to employ for financial markets surveillance and as such practice of investment management. We argue that anyone interested in using financial stability indices as indicators of financial conditions and the level of financial stress would benefit from tracking several indices and not just one. The second essay examines the effectiveness of capital controls and macroprudential policies as ways to manage the volume of international capital flows, controlling for other determinants. The findings show that capital controls imposed on inflows generally prevail over controls imposed on outflows in reducing the magnitude of capital flows. The results are consistent with the pecking order theory on capital flows and are connected with the riskiness of different asset classes. For a sample of 112 countries over 2000 and 2016, we find that FX and/or countercyclical reserve (RR_REV) and general countercyclical capital buffer requirements (CTC), reserve requirement ratios (RR) and concentration limits (CONC) are the most effective macroprudential policies for managing countries' exposures to global liquidity fluctuations. Moreover, progress is being made to reduce the systemic risks created by systemically important financial institutions (SIFIs) using macroprudential policies. The results reflect recent developments in Basel III regulations and shed light on the effective calibration of capital flow regulations to country-specific circumstances. The final essay examines the link between global governance indicators and patterns of gross capital flows, controlling for other determinants. For a sample of 67 countries between 2000 and 2016, we contribute to explain the existence of the Lucas paradox (1990) on "why doesn't capital flow from rich to poor countries" and the Feldstein-Horioka puzzle (1980). The findings show that institutional quality rather than the effect of diminishing returns of capital is a key explanation for the Lucas paradox. Finally, we provide new evidence on the relationship between the multidimensional nature of financial development and gross capital flows. The findings show the importance and predominance of financial institutions versus financial markets in the dissemination of international capital flows across counties.

The docotoral thesis titled 'Modeling the effects of Transient Stream Flow on Solute Dynamics in Stream Banks and Intra-meander Zones' investigates flow and solute dynamcis across surface water-groundwater interface under dynamic flow conditons through numerical simulations. The abstract of the thesis is as follows: Waters from various sources meet at the interface between streams and groundwater. Due to their different origins, these waters often have contrasting chemical signatures and therefore mixing of water at the interface may lead to significant changes in both surface and subsurface water quality. The riparian zone adjacent to the stream serves as transition region between groundwater and stream water, where complex water and solute mixing and transport processes occur. Predicting the direction and the magnitude of solute exchanges and the extent of transformations within the riparian zone is challenging due to the varying hydrologic and chemical conditions as well as heterogeneous morphological features which result in complex, three-dimensional flow patterns. The direction of water flow and solute transport in the riparian zone typically varies over time as a result of fluctuating stream water and groundwater levels. Particularly, increasing groundwater levels can mobilize solutes from the unsaturated zone which can be subsequently transported into the stream. Such complex, spatially and temporally varying processes are hard to capture with field observations alone and therefore modeling approaches are required to predict the system behavior as well as to understand the role of individual factors. In this thesis, we investigate the inter-connectivity of streamthe s and adjacent riparia zones in the context of water and solute exchanges both laterally for bank storage and longitudinally for hyporheic flow through meander bends. Using numerical modeling, the transient effect of stream flow events on solute transport and transformation within the initially unsaturated part of stream banks and meander bends have been simulated using a systematic set of hydrological, chemical and morphological scenarios. A two dimensional variably saturated media groundwater modeling set up was used to explore solute dynamics during bank flows. We simulated exchanges between stream and adjacent riparian zone driven by stream stage fluctuations during stream discharge events. To elucidate the effect of magnitude and duration of discharge events, we developed a number of single discharge event scenarios with systematically varying peak heights and event duration. The dominant solute layer was represented by applying high solute concentration in upper unsaturated riparian zone profile. Simulated results show that bank flows generated by high stream flow events can trigger solute mobilization in near stream riparian soils and subsequently export significant amounts of solutes into the stream. The timing and amount of solute export is linked to the shape of the discharge event. Higher peaks and increased duration significantly enhance solute export, however, peak height is found to be the dominant control for overall lateral mass export. The mobilized solutes are transported towards the stream in two stages (1) by return flow of stream water that was stored in the riparian zone during the event and (2) by vertical movement to the groundwater under gravity drainage from the unsaturated parts of the riparian zone, which lasts for significantly longer time (> 400 days) resulting in a theoretically long tailing of bank outflows and solute mass outfluxes. Our bank flow simulations demonstrate that strong stream discharge events are likely to mobilize and export significant quantity of solutes from near stream riparian zones into the stream. Furthermore, the impact of short-term stream discharge variations on solute exchange may sustain for long times after the flow event. Meanders are prominent morphological features of stream systems which exhibit unique hydrodynamics. The water surface elevation difference across the inner bank of a meander induces lateral hyporheic exchange flow through the intrameander region, leading to solute transport and reactions within intra-meander region. We examine the impact of different meander geometries on the intra-meander hyporheic flow field and solute mobilization under both steady-state and transient flow conditions. In order to explore the impact of meander morphology on intrameander flow, a number of theoretical meander shape scenarios, representing various meander evolution stages, ranging from a typical initial to advanced stage (near cut off ) meander were developed. Three dimensional steady-state numerical groundwater flow simulations including the unsaturated zone were performed for the intra-meander region for all meander scenarios. The meandering stream was implemented in the model by adjusting the top layers of the modeling domain to the streambed elevation. Residence times for the intra-meander region were computed by advective particle tracking across the inner bank of meander. Selected steady state cases were extended to transient flow simulations to evaluate the impact of stream discharge events on the temporal behavior of the water exchange and solute transport in the intra-meander region. Transient hydraulic heads obtained from the surface water model were applied as transient head boundary conditions to the streambed cells of the groundwater model. Similar to the bank storage case, a high concentration of solute (carbon source) representing the dominant solute layer in the riparian profile was added in the unsaturated zone to evaluate the effect of stream flow event on mobilization and transport from the unsaturated part of intrameander region. Additionally, potential chemical reactions of aerobic respiration by the entry of oxygen rich surface water into subsurface as well denitrification due to stream and groundwater borne nitrates were also simulated. The results indicate that intra-meander mean residence times ranging from 18 to 61 days are influenced by meander geometry, as well as the size of the intra-meander area. We found that, intra-meander hydraulic gradient is the major control of RTs. In general, larger intra-meander areas lead to longer flow paths and higher mean intra-meander residence times (MRTs), whereas increased meander sinuosity results in shorter MRTs. The vertical extent of hyporheic flow paths generally decreases with increasing sinuosity. Transient modeling of hyporheic flow through meanders reveals that large stream flow events mobilize solutes from the unsaturated portion of intra-meander region leading to consequent transport into the stream via hyporheic flow. Advective solute transport dominates during the flow event; however significant amount of carbon is also consumed by aerobic respiration and denitrification. These reactions continue after the flow events depending upon the availability of carbon source. The thesis demonstrates that bank flows and intra-meander hyporheic exchange flows trigger solute mobilization from the dominant solute source layers in the RZ. Stream flow events driven water table fluctuations in the stream bank and in the intra-meander region transport substantial amount of solutes from the unsaturated RZ into the stream and therefore have significant potential to alter stream water quality.:Declaration Abstract Zusammenfassung 1 General Introduction 1.1 Background and Motivation 1.2 Hydrology and Riparian zones 1.2.1 Transport processes driven by fluctuation in riparian water table depth 1.2.1.1 Upland control 1.2.1.2 Stream control 1.2.2 Biochemical Transformations within the Riparian Zone 1.3 Types and scales of stream-riparian exchange 1.3.1 Hyporheic Exchange 1.3.1.1 Small Scale Vertical HEF 1.3.1.2 Large Scale lateral HEF 1.3.2 Bank Storage 1.4 Methods for estimation of GW-SW exchanges 1.4.1 Field Methods 1.4.1.1 Direct measurement of water flux 1.4.1.2 Tracer based Methods 1.4.2 Modeling Methods 1.4.2.1 Transient storage models 1.4.2.2 Physically based models 1.5 Research gaps and need 1.6 Objectives of the research 1.7 Thesis Outline 2 Flow and Transport Dynamics during Bank Flows 2.1 Introduction 2.2 Methods 2.2.1 Concept and modeling setup 2.2.2 Numerical Model 2.2.3 Stream discharge events 2.2.4 Model results evaluation 2.3 Results and discussion 2.3.1 Response of water and solute exchange to stream discharge events 2.3.1.1 Water exchange time scales 2.3.1.2 Stream water solute concentration 2.3.2 Solute mobilization within the riparian zone 2.3.3 Influence of peak height and event duration on solute mass export towards the stream 2.3.4 Effects of event hydrograph shape on stream water solute concentration 2.3.5 Model limitations and future studies 2.4 Summary and Conclusions Appendix 2 3 Flow and Transport Dynamics within Intra-Meander Zone 3.1 Introduction 3.2 Methods 3.2.1 Meander Shape Scenarios 3.2.2 Surface Water Simulations 3.2.3 3D Groundwater Flow Simulations with Modeling code MIN3P 3.2.3.1 Steady Flow Simulations 3.2.3.2 Stream flow event and Solute Mobilization Set-up 3.2.4 Reactive Transport 3.3 Results and Discussion 3.3.1 Groundwater heads and flow paths in the saturated intrameander zone 3.3.1.1 Groundwater heads 3.3.1.2 Flow paths and isochrones 3.3.1.3 Vertical extent of flow paths 3.3.2 Intra-Meander Residence Time Distribution 3.3.3 Factors affecting intra-meander flow and residence times 3.3.3.1 intra-meander hydraulic gradient 3.3.3.2 Maximum penetration depth 3.3.3.3 Meander sinuosity 3.3.3.4 intra-meander area (A) 3.3.4 Influence of Discharge Event on intra-meander Flow and Solute Transport 3.3.4.1 Spatial distribution of groundwater head and solute concentration 3.3.4.2 Time scales of intra-meander groundwater heads and solute transport 3.3.4.3 Solute export during stream discharge event 3.3.5 Intra-meander reactive transport during stream discharge event 3.3.5.1 Impact of stream discharge on aerobic respiration and denitrification 3.3.5.2 DOC mass removal during stream discharge event 3.4 Summary and Conclusions Appendix 3 4 General Summary and Conclusions 4.1 Summary 4.2 Conclusions 4.2.1 Flow and Transport Dynamics in Near Stream Riparian Zone (Bank Flows) 4.2.2 Flow and Transport Dynamics within Intra-Meander Zone 4.3 Model Limitations and Future Studies Bibliography Acknowledgement