Climate change causes temperatures to rise worldwide. Up until now it is unclear what effect this has on the global water cycle. In this study the output of two GFDL model experiments were thoroughly investigated and used in the moisture tracking model WAM-2layers, accounting for model runs in a past case in the end-20th century and future case in the end-21st century, based on RCP8.5. This is done in order to acquire knowledge on what will happen to the global as well as regional water cycle in the future and to find out what processes provide climate change to have an effect on the water cycle. Changes in precipitation and evaporation rates are spatially highly dissimilar, therefore regional differences can be distinguished. Past studies have suggested that a DDWW paradigm - where dry regions dry out further and wet regions get wetter - will take place with climate change. Even though in some regions this might happen, results show that on land this is not necessarily the case - at least, if precipitation rate is the benchmark for a region to get drier or wetter. Processed GFDL data concludes that dry region Western Sahara gets wetter while dry region Middle East gets drier and wet region Indonesia gets wetter while wet region Amazonia gets drier. The DDWW paradigm covers another aspect as well, that there will be a larger spatial variability for variables characterising a region to be wet or dry. However, while everywhere on the globe the temperatures will rise according to the GFDL data, the spread of the yearly mean temperatures over the globe will actually decrease, meaning that mean yearly temperature in the coldest place will lie closer to the mean yearly temperature in the warmest place. This is also the case for mean yearly precipitation and evaporation rates. The mean yearly precipitation and evaporation rate in the driest place will lie closer to the mean yearly precipitation and evaporation rate in the wettest place in the future case. Continents show divergent effects in water cycle due to climate change. The continents with relatively larger sources of terrestrial moisture - North America, Europe and Asia - have an increased water cycle with higher precipitation and evaporation rates in the future. The increases in precipitation rates on these continents will originate from terrestrial evaporation and a higher percentage of evaporation will return as precipitation on land. South America shows a distinct effect, different than all other continents. This continent shows a decreased water cycle with lower precipitation and evaporation rates in the future. Of this precipitation a lower percentage comes from land and the evaporated moisture will return less on land. Africa and Oceania show another pattern. Both these continents will experience more precipitation in the future case, but this moisture will come from oceanic evaporation. Two case study areas are examined in more depth by looking at seasonality effects. A case study in the Amazon forest shows a distinct dry season in the future case, the effect of possible land use change in the Amazon forest. Less evaporation that is an effect of deforestation of the rain forest gives less moisture for clouds to form and precipitate. Moisture evaporates from the oceans on the East of Amazon region but moves over the region before it can precipitate. A case study in Western Africa shows a magnified rain season. The analyses show that during the wet season in the future case there in an increased amount of moisture coming from the oceans West and South of Western Africa and meanwhile there was still moisture coming in from the tropical rain forest East of the area.

Valdivia is a Chilean city located near an estuary system, 800 km south of Santiago. The navigation capacity of the Valdivia river mainly determines the present state and future possibilities for the welfare of the city. Since sedimentation problems arose in the river, the capacity for navigation became limited. The ministry of Valdivia therefore desires a solution for this problem in order to create possibilities for future growth. However, it is not known to what extent solutions for the sedimentation problem will actually contribute to an increase of welfare. By identifying the problem for the Ministry of Public Works of Chile, the boundaries and goal of the project could be set. In this research an attempt is made to answer the following research question: How can the surplus of sediment in the Valdivia river be remedied and to what extent will this contribute to the economic and social values of the city of Valdivia? In order to know how to remedy the surplus of sediment, a qualitative analysis of probable causes of the sedimentation was necessary. The main subjects which were researched by means of data and literature are tidal influence, river discharges, sediment composition and salt intrusion. With this knowledge it was concluded that the directions and magnitudes of flow lines in the river system can give good indications on what locations sedimentation can occur. The interaction between tidal currents and river discharges are the main drivers behind these flow characteristics. To verify the theoretical analysis, a basic Delft3D model was set up containing only tidal movement and river discharges. The pattern of the flow lines which was obtained from the Delft3D model supports the possibility that sedimentation occurs on the current identified sedimentation locations. Although other hydrological and morphological processes were found to possibly influence sedimentation rates in the river, qualitative data for studying these processes were missing. The current Delft3D model is therefore a good result regarding the available data and can be seen as a part of preliminary research in order to support further studies. Because the exact causes of the sedimentation were not identified in this research, it was not possible to come up with suitable solutions and to research how these solutions could affect the system. However, in order to gain insight in the effects of a river system without sedimentation problems, a fictitious scenario was studied by means of a social cost benefit analysis. The goal of the social costs and benefits analysis was to give insight in what factors should be taken into account when considering a project plan which solves the sedimentation problem. A dredging design was made in order to make the Valdivia river navigable for larger cargo vessels to increase the trading capacity of Valdivia. This dredging design comprises the deepening of the Valdivia river to a minimum water depth of 10 meters. Considering investment and maintenance costs of the dredging activities of this magnitude, it is concluded that the costs are not profitable compared to the social and economic effects of a higher traffic intensity on the river. With the social costs and benefits analysis all effects of solving the sedimentation problem are inventoried. When the Delft3D model can identify what the remedy of the sedimentation could be, the impact on the economic and social values of Valdivia can be determined. This research was not sufficient to answer the research question. Both the Delft3D model and the SCBA model were lacking accurate and reliable data. To expand this research, it is necessary to collect the data of which an overview has been made. Therefore, this research can serve as a preliminary study for further research. It is recommended that after data collection, solutions will be identified which can solve the sedimentation problem. These solutions need to be compared with a scenario analysis in order to decide on which is the most suitable solution for the sedimentation problem. Besides this, it is advised to research whether it is actually necessary to expand the river for transport when looking at all actors involved.