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The research question addressed in this study is ”To what extent does the presence of a cloud forest canopy impact the Mestelá River catchment and how will this affect the various involved stakeholders?”. The study aims to investigate the importance of cloud forests in the Mestelá River catchment, Alta Verapaz, Guatemala, related to water security and the social impact of cloud forest conservation and management. The research methods used in this study were a combination of quantitative and qualitative methods. Cloud forests play a vital role in regulating water flow in catchments. The Mestelá River catchment, where the NGO Community Cloud Forest Conservation (CCFC) is situated, is the focus of this research. The project’s primary aim was to establish a long-term canopy setup, ensuring future data collection. The project’s scope encompasses a range of methodologies, including the installation of a long-term measurement station in the canopy, computation of the Mestelá River discharge, the development of a rating curve, and the utilisation of a FLEX-Topo model to simulate the hydrological cycle in the catchment. Additionally, a stakeholder management analysis was conducted to understand the complex impact of cloud forests (conservation) on various stakeholders. The study did not explicitly formulate any hypotheses, but the findings provide evidence for the impact of cloud forest canopies on river catchments and discharge. The study also has limitations, including the small sample size and the lack of long-term data. However, the study provides valuable insights into the importance of cloud forest ecosystems for water security and the social impact of cloud forest conservation and management. The stakeholder analysis reveals that for CCFC two methods of advocacy can be used. Whilst the CCFC is effective in bottom-up engagement with the community, in addition, a strip for small children was constructed. For top-down advocacy, using the FLEX-Topo m, Civil Engineering

The construction of drinking-water reservoirs in previously free-flowing river basins introduces challenges in operational water management, especially in data scarce environments. Often resulting in effectively un- gauged basins. In order to be able to estimate the expected increase in water supply, the hydrology of the ungauged sub-basins must be deduced from the whole basin. This can be done by estimation based on rel- ative area to the whole. However such a method neglects the potential differences in boundary conditions and ecosystems. This research presents an improved hydrological modeling method. Through the devel- opment of a process-based, flexible model (FLEX-Topo) with four classes the hydrology of a polar-desert, high-mountainous basin in the Cordillera Real (Bolivia) is investigated. To increase realism additional data- sources are used in model development and calibration. Internal model states related to vegetation- and snow-presence are evaluated in the frequency- respectively time domain. The calibrated model is applied to the sub-domains to identify important hydrological differences. To further support operational decision making the correlation between the ENSO-Index and the local climate is investigated, which is not found to be significant. The research shows that the developed FLEX-Topo model is suited to function in a data scarce- and low data quality environment. The model is able to reproduce the natural flow regime to a high degree. Appropriate model realism can be assumed and sensible sub-basin hydrology investigation is achieved. Sub- sequent reservoir dynamics hind-casting is performed to increase knowledge on the to be expected flows and water levels., Water Management | Hydrology

In the past, hydrologic modeling of surface water resources has mainly focused on simulating the hydrologic cycle at local to regional catchment modeling domains. There now exists a level of maturity among the catchment, global water security, and land surface modeling communities such that these communities are converging toward continental domain hydrologic models. This commentary, written from a catchment hydrology community perspective, provides a review of progress in each community toward this achievement, identifies common challenges the communities face, and details immediate and specific areas in which these communities can mutually benefit one another from the convergence of their research perspectives. Those include: (1) creating new incentives and infrastructure to report and share model inputs, outputs, and parameters in data services and open access, machine-independent formats for model replication or reanalysis; (2) ensuring that hydrologic models have: sufficient complexity to represent the dominant physical processes and adequate representation of anthropogenic impacts on the terrestrial water cycle, a process-based approach to model parameter estimation, and appropriate parameterizations to represent large-scale fluxes and scaling behavior; (3) maintaining a balance between model complexity and data availability as well as uncertainties; and (4) quantifying and communicating significant advancements toward these modeling goals., CCC:000368421500038

In this thesis, a novel landscape-based hydrological model is presented that was developed and tested in numerous catchments around the world with various landscapes and climate conditions. A landscape is considered to consist of a topography and an ecosystem living on it. Firstly, the influence of climate on hydrological process was studied. It was assumed that an ecosystem organizes its root zone storage capacity to overcome droughts with a certain return period to survive, but not larger than needed, so as to save energy and nutrients. It was found that ecosystems organize their root zone storage capacity to overcome droughts with a return period of about 20 years. This indicates that the root zone storage capacity is the optimal result of an ecosystem adjusting to the climate. The size of the root zone storage capacity in turn has great influence on virtually all hydrological processes. Subsequently, in order to understand the influence of topography on hydrological behavior, we selected a cold-arid catchment in the upper Heihe River in China as the study site. The influence of topography was explicitly considered in the FLEX-Topo model. Firstly, topography data was applied to make a landscape classification. It is interesting to note that also the land cover map can be derived from topography information, indicating the great influence of topography on natural land cover. And then, within the framework of FLEX-Topo modelling approach, we applied a semi-distributed model structure to describe the different runoff generation mechanisms in different landscapes. We found that FLEX-Topo, allowing for catchment heterogeneity, performs much better than lumped models while transferring both model and optimized parameter sets to two nested catchments. To test the influence of vegetation and topography information on model transferability separately, a stepwise modelling approach was applied in 6 catchments in Thailand. Each model was calibrated on one catchment and then, Water management, Civil Engineering and Geosciences

The Mara River originates in Kenya in the Mau Escarpment and flows through the Serengeti ecosystem into Lake Victoria in Tanzania; in total it is about 395 km long. In this river, human interventions have led to increased of agricultural areas. As a result, increased fast runoff and top soil erosion is expected. Consequently, more sediments is expected to be transported to the river, thus polluting it. This research focuses on the modelling of the hydrology and soil loss from the catchment to locate the main sources of transported suspended sediment in the Mara River Basin. The suspended load in the river consists of coarse sediments in the river bed and fine sediments in the wash load originating from the top soil in the entire catchment. The main sources of the coarse sediments are assessed hydraulically whereas for the fine sediments a hydrological model is combined with an empirical sediment yield model. The main sources for the fine suspended sediments are the grasslands in the Sand and the crop lands in the Lower sub-catchment. The coarse sediments are found to originate from the river itself which has caused and still causes meandering., NUS-TUD Double MSc Degree Programme, Water Management, Civil Engineering and Geosciences

A common practice for hydrologists to determine the performance of a hydrological model and its parameter values, is by calibrating the model parameters on observed discharge data, but this data is not always available. For this reason, other data should be used as complementary data in order to reduce the uncertainty of outflow and processes in the ungauged basins. This thesis presents a case study on an area in Baden-Württemberg, Germany, to see whether groundwaterlevel data can be used as complementary data for hydrological models of ungauged basins. It has been divided into two Hydrological Response Units (Lowland and Hillslope) with use of the surface slope and the height above the nearest drainage (HAND) algorithm. The main result is that a combined addition of groundwater level measurements and constraints did show reduced uncertainty, and thus improvement, of the internal model processes, especially the fluxes towards and out of the slow responding reservoir. Validation of these processes still remains difficult in ungauged areas, but it is believed that valid results can be made on the outflow out of the lowland areas with a combination of constraints and groundwater measurements to determine internal processes, and evaporation estimates obtained from satellite imagery to reduce the uncertainty of the total runoff out of the area., Water Resources, Water Management, Civil Engineering and Geosciences

This study explores the possibility of calibrating a conceptual hydrological model to tracer (Oxygen-18) data measured in streamflow with the ultimate goal to predict discharge. The hypothesis is that (changes in) Oxygen-18 concentrations in the stream should tell something about the relative contribution of fast runoff compared to slow runoff (groundwater flow) inside the stream. A conceptual hydrological model incorporating both tracer dynamics and discharge should be able to model this. Using tracer previously measured in the Brugga catchment (South-West Germany) by people of the University of Freiburg, both lumped and FLEX-Topo inspired models are developed and calibrated to this data. Results showed that of all models considered, only a FLEX-Topo inspired model, containing a variable groundwater level that is able to occasionally (partially or wholly) submerge the wetland model structure, was able to predict a decent hydrograph when calibrating purely on tracer data. The results indicate that calibration of a FLEX-Topo inspired model to only tracer data is a real possibility, and opens the door to more sophisticated modelling attempts, for instance calibration on multiple tracers or multiple tracer sampling points., Hydrology, Water Management, Civil Engineering and Geosciences