During the recent summers, Gotland has suffered from drinking water shortage and due to the climate change, the water shortage can possible increase in the future. To find a solution, the Swedish Environmental Research Institute IVL and Region Gotland are going to build a testbed at Storsudret located on the south of Gotland, to investigate different sustainable solutions. One possible solution is to increase the water level in Lake Mjölhatteträsk, located at Storsudret, to increase the water storage. This master thesis has focused on the water balance of the lake to understand whether it is possible to store more water in the lake and how large areas that would be flooded in the event of an increase in the water level. This has been done using a combination of field data sampling with geophysical methods, hydraulic tests, water depth measurements, existing hydrometeorological data from Lantmäteriet and the Geological Survey of Sweden (SGU) and modelling with the tools MIKE SHE and MIKE HYDRO River created by DHI and also GIS. The result of this master thesis showed that there is a very thin soil layer with possibly high clay and silt content to the west of the lake. At the bottom of the lake, a thick clay layer exists which reduces the hydraulic connection between the lake and the surroundings. The potential to store and extract water in the sand layer in the west is therefore small. However, there is potential to produce enough water in the lake to meet the water demand at Storsudret, according to the model created in MIKE SHE. This would require a dam at a suggested location at the outflow with a height of 0.12 m. / Gotland har under de senaste åren lidit utav vattenbrist under somrarna och på grund av klimatförändringarna är det möjligt att vattenbristen kan komma att öka i framtiden. För att hitta en lösning har Svenska Miljöinstitutet (IVL) och region Gotland fått i uppgift att anlägga en testbädd på Storsudret på södra Gotland, där olika hållbara lösningar ska testas. En möjlig lösning är att höja vattennivån i sjön Mjölhatteträsk på Storsudret för att på så vis kunna lagra mer vatten. Den här masteruppsatsen har fokuserat på hur sjöns vattenbalans ser ut för att förstå om det är möjligt att lagra mer vatten i sjön och hur stora områden som skulle bli översvämmade vid en ökning av vattennivån. Detta har gjorts med hjälp av en kombination av fältstudier med geofysiska mätningar, hydrauliska tester, vattendjupmätningar och flödesmätningar tillsammans med digitala databaser från Lantmäteriet och Sveriges Geologiska Undersökning (SGU) samt modellering med verktygen MIKE SHE och MIKE HYDRO River som skapats av DHI och även GIS. Resultatet för den här masteruppsatsen visade att det finns ett mycket tunt jordlager med eventuellt högt ler och silt innehåll väster om sjön. Vid botten av sjön finns ett tjockt lerlager som minskar den hydrauliska förbindelsen mellan sjön och omgivningen. Potentialen att lagra och utvinna vatten i sandlagret i väst är därmed liten. Däremot finns det potential att producera tillräckligt med vatten i sjön för att kunna uppfylla vattenbehovet på Storsudret, enligt modellen skapad i MIKE SHE. Detta skulle innebära en dam vid en föreslagen punkt vid utflödet som har en höjd på 0.12 m.

[pt] O objetivo deste trabalho é avaliar a contaminação da água subterrânea por metais pesados provenientes da Área de Disposição de Resíduos (ADR) do município de Resende, RJ. O escopo compreende um estudo preliminar com base em levantamento e mapeamento de dados espaciais; investigação in situ e em laboratório, incluindo a instalação de poços de monitoramento, amostragens e caracterização de solos, águas subterrâneas e chorume, ensaios de condutividade hidráulica, K; e modelagem da pluma de contaminação usando o programa MIKE SHE. Em geral, a caracterização apresentou argilas arenosas, siltes arenosos e, areias siltosas, cujos principais minerais foram quartzo, caulinita, e muscovita com presença de biotita e feldspato. Os valores de K variaram de 10(-5) a 10(-6) m/s; o pH entre 4,59 e 6,93 (água subterrânea) e 7,93 e 8,16 (chorume); a condutividade elétrica na água variou de 0,032 a 7,113 mS/cm, coerente com os sólidos totais dissolvidos e com maiores valores no chorume e no poço mais próximo a ADR. Análises detectaram 14 metais dissolvidos (Al, As, B, Ba, Cd, Co, Cr, Fe, Hg, Mn, Ni, Pb, Se e Zn) em concentrações acima do permissível por lei. A modelagem mostrou como a distribuição espacial e a anisotropia dos solos influenciam o fluxo e transporte do cloreto (advectivo) e do cromo (sorção). Quando são considerados solos anisotrópicos, a pluma de Cl- atinge o Rio Paraíba do Sul, à 2,5 km de distância, em 43 anos enquanto a pluma do Cr dista apenas 55 m da fonte. Embora os resultados experimentais não tenham sido claros em determinar se todos os metais encontrados são necessariamente da fonte de contaminação da ADR ou de origens naturais, as simulações deste modelo indicaram baixo impacto ambiental dos metais para o rio. / [en] The objective of this work is to evaluate the groundwater contamination due to heavy metals from the Waste Disposal Area (WDA) in the municipality of Resende, RJ. The scope consists of a preliminary assessment based on surveying and mapping spatial data; in situ and laboratory investigation, including the installation of monitoring wells, sampling and characterization of soils, groundwater and waste leachate, hydraulic conductivity tests, K; and contaminant plume modelling using the program MIKE SHE. Overall, the characterization revealed sandy clays, sandy silts and silty sands. The predominant minerals were quartz, kaolinite, and muscovite along with the presence of biotite and feldspar. The values of K varied from 10(-5) to 10(-6) m/s; the pH between 4.59 and 6.93 (groundwater) and 7.93 and 8.16 (leachate); the electrical conductivity in the water varied from 0.032 to 7.113 mS/cm, consistent with the total dissolved solids and with higher values attributed to the leachate and the well closest to the WDA. Analysis detected 14 dissolved metals (Al, As, B, Ba, Cd, Co, Cr, Fe, Hg, Mn, Ni, Pb, Se and Zn) with concentrations above the legal limit. The model illustrated how the soils spatial distribution and anisotropy influence the flow and transport of chloride (advective) and chromium (sorption). When considering anisotropic soils, the Clplume reached the Paraíba do Sul River, 2.5 km away, in 43 years while the Cr plume only moved 55 m from the source. Although the experimental results were not clear in determining whether all the metals found necessarily originated from the contaminant source from the WDA or from natural origins, the simulations of this model indicated a low environmental impact to the river.

Due to precipitation poor winters and springs and over-exploitation of groundwater reserves during the summer months as a consequence of tourism, the island of Gotland has experienced fresh water shortages during recent years which has led to harsh restrictions in the use of municipal water. In order to find a solution to the islands fresh water problems, the region of Gotland and the Swedish Environmental Institute (IVL) have initiated a project in which the southernmost part of Gotland, Storsudret, will be used as a test site for new methods of sustainable freshwater storage and extraction methods. A, for Sweden, new method currently being investigated is the use of subsurface dams in order to increase the storage capacity of soil groundwater, thus increasing the possible extractions. Methods for finding suitable sites for subsurface dams has been investigated by Imran Jamali, 2016, and Ludvig Almqvist, 2017. There is however a need in further investigating and developing methods for subsurface dam location. This master thesis has focused on performing on-site data collection and on the use of groundwater flow model to evaluate the possibility of placing a subsurface dam on Storsudret, as steps in a method to localize areas suitable for subsurface dams. On site data was collected through resistivity measurements and water level measurements. This was used as input data for the flow model, MIKE SHE, together with more general GIS-data available. Flow modelling was performed during the period 2015-2018, which included the initially dry years of 2015-16 and the summer of 2017, and the more precipitation rich second half of 2017 and spring of 2018. Subsurface dams were modelled to investigate the results on the surroundings. The result did not show any obvious locations for the placement of a subsurface dam within the modelled area. The site considered to be most suitable for dam placement was modelled but showed only a rather small additional stored volume. However, the model result indicated that large possibilities for freshwater extraction already could be present in an existing geological formation in the area, even without the presence of a subsurface dam. As a tool for finding the specific location of groundwater dams, it was concluded that MIKE SHE gives a good overview over the general hydrogeological features and flow paths. Thus, it is a valuable tool when it comes to finding interesting sites for further investigations. However, due to problems in obtaining detailed enough input data, the model is considered to be less suitable for finding specific locations for dam placement when investigating a larger domain. / På grund av nederbördsfattiga vintrar och ett överuttag från grundvattenreservoarerna under turistsäsongen på somrarna, har Gotland erfarit vattenbrist under senare år vilket lett till hårda bevattningsförbud för såväl kommunalt och enskilt vatten. För att hitta en lösning på denna vattenbrist har Region Gotland och Svenska Miljöinstitutet (IVL) initierat ett projekt på den södra delen av Gotland, Storsudret, som kommer att användas som en testplats för nya lösningar inom lagring och uttag av färskvatten. En, för Sverige, ny metod som för nuvarande undersöks är användandet av grundvattendammar som ett sätt att öka lagringskapaciteten i marken och på så sätt kunna öka uttagen av grundvatten. Metoder för att finna lämpliga platser för grundvattendammar har undersökts av Imran Jamali, 2016, och Ludvig Almqvist, 2017. Därtill finns ett behov av att vidare undersöka och utveckla metoder för lokalisering av grundvattendammar. Denna masteruppsats har fokuserat på att utföra data-inhämtning i fält och bygga upp en grundvattenflödesmodell för att utvärdera möjligheten att placera en grundvattendam på Storsudret, som ett vidare steg i att utveckla en metod för att finna lämpliga platser för grundvattendammar. Data från fältundersökningar hämtades genom resistivitetsmätningar och vattenståndsmätningar. Dessa data användes som inmatning i grundvattenflödesmodellen, MIKE SHE, tillsammans med mer generell GIS-data. Flödesmodellering utfördes under perioden 2015-2018, vilket inkluderade torrår under perioden 2015-2016 och slutet av sommaren 2017 och mer nederbördsrik period under hösten 2017 och våren 2018. Grundvattendammar modellerades för att undersöka områdespåverkan. Resultaten visade på ingen självklar lokalisering för en grundvattendamm inom det modellerade området, på grund av platt geologi utan tydliga utflödespunkter blev resultatet av en damm endast en liten ökad grundvattenvolym. Däremot visade modellresultaten att stora uttagsmöjligheter för grundvatten redan fanns i existerande geologiska formationer även utan en grundvattendamm närvarande. Som ett steg i metoden att finna lämpliga platser för grundvattendammar var MIKE SHE ett bra verktyg för att ge en god överblick över de generella hydrogeologiska flödena. MIKE SHE är ett värdefullt verktyg när det kommer till att hitta intressanta platser för vidare undersökningar. Däremot fanns problem med att finna detaljerade inmatningsdata vilket gör modellen mindre lämplig för att finna exakta grundvattendamsplaceringar inom ett större område.

This study evaluated the impacts of shallow and deep open drains on groundwater levels and drain performance under varying climate scenarios and irrigation application rates. The MIKE SHE model used for this study is an advanced and fully spatially distributed hydrological model. Three drain depths, climates and irrigation application rates were considered. The drains depths included 0, 1 and 2 m deep drains. The annual rainfall and meteorological data were collected from study area from 1976 to 2004 and analysed to identify the typical wet, average and dry years within the record. Similarly three irrigation application rates included 0, 10 and 16 ML/ha-annum. All together twenty seven scenarios (3 drains depths, 3 climates and 3 irrigation application rates) were simulated. The observed soil physical and hydrological data were used to calibrate and validate the model. Mean square error (R[superscript]2) of the simulated and observed water table data varied from 0.7 to 0.87. Once validated the MIKE SHE model was used to evaluate the effectiveness of 1 and 2 metre deep drains. The simulated water table depth, unsaturated zone deficit, exchange between unsaturated and saturated zones, drain outflow and overland flow were used to analyse their performance. The modeling results showed that the waterlogging was extensive and prolonged during winter months under the no drainage and no irrigation scenario. In the wet climate scenario, the duration of water logging was longer than in the average climate scenario during the winter months. In the dry climate scenario no waterlogging occurred during the high rainfall period. The water table reached soil surface during the winter season in the case of wet and average climate. For the dry climate, the water table was about 0.9 metres below soil surface during winter. / One and 2 metre deep drains lowered the water table up to 0.9 and 1.8 metres in winter for the wet climate when there was no irrigation application. One metre deep drains proved effective in controlling water table during wet and average climate without application of irrigation water. One metre deep drains were more effective in controlling waterlogging a in wet, average and dry years when the irrigation application rate was 10 ML/ha-annum. With 16 ML/ha-annum irrigation application, 1 metre deep drains did not perform as efficiently as 2 metre deep drains in controlling the water table and waterlogging. In the dry climate scenario, without irrigation application, 1 metre deep drains were not required as there was not enough flux from rainfall and irrigation to raise the water table and create waterlogging risks. Two metre deep drains lowered the water table to greater depths in the wet, average and dry climate scenarios respectively when no irrigation was applied. They managed water table better in wet and average climate with 10 and 16 ML/ha-annum irrigation application rate. Again in the dry climate, without irrigation application 2 metre deep drains were not required as there was a minimal risk of waterlogging. The recharge to the groundwater table in the no drainage case was far greater than for the 1 and 2 metre deep drainage scenarios. The recharge was higher in case of 1 metre deep drains than 2 metre deep drains in wet and average climate during winter season. / There was no recharge to ground water with 1 and 2 metre deep drains under the dry climate scenarios and summer season without irrigation application as there was not enough water to move from the ground surface to the unsaturated and saturated zones. When 10 ML/ha-annum irrigation rate was applied during wet, average and dry climate respectively, 1 metre deep drains proved enough drainage to manage the recharge into the groundwater table with a dry climate. For the wet and average climate scenarios, given a 10 ML/ha-annum irrigation application rate, 2 metre deep drains managed recharge better than 1 metre deep drains. Two metres deep drains with a 10 ML/ha-annum irrigation application rate led to excessive drainage of water from the saturated zone in the dry climate scenario. Two metres deep drains managed recharge better with a 16 ML/ha-annum irrigation application rate in the wet and average climate scenarios than the 1 metre deep drains. Two metres deep drains again led to excessive drainage of water from the saturated zone in dry climate. In brief, 1 metre deep drains performed efficiently in the wet and average climate scenarios with and without a 10 ML/ha-annum irrigation application rate. One metre deep drains are not required for the dry climate scenario. Two metre deep drains performed efficiently in the wet and average climate scenarios with 16 ML/ha-annum irrigation application rate. Two metre deep drains are not required for the dry climate scenario.

Αντικείμενο της παρούσας εργασίας αποτελεί η εφαρμογή του μοντέλου βροχής-απορροής MIKE-SHE στο ορεινό τμήμα της λεκάνης του Γλαύκου. Σκοπός της μελέτης ήταν η διαμόρφωση της εσωτερικής δομής του MIKE-SHE έτσι ώστε να προσομοιώνει την διαδικασία της απορροής στην λεκάνη του Γλαύκου, η βαθμονόμηση των παραμέτρων του και η σύγκριση των αποτελεσμάτων των μοντέλων βροχής-απορροής MIKE-SHE και ENNS (Nachtnebel et al., 1993). Η ρύθμιση του μοντέλου ENNS πραγματοποιήθηκε στα πλαίσια της εργασίας των Kaleris and Langousis (2012). Ειδικότερα, στο πρώτο κεφάλαιο της εργασίας καθορίζεται η περιοχή μελέτης, τα χαρακτηριστικά της και τα δεδομένα εισαγωγής στο υδρολογικό μοντέλο MIKE SHE. Τα μορφολογικά χαρακτηριστικά αποτελούν η γεωμετρία, η γεωλογία και οι χρήσεις γης της λεκάνης απορροής. Επιπλέον παρουσιάζονται τα διαθέσιμα δεδομένα(βροχόπτωση, θερμοκρασία, μετρημένη απορροή) και η αξιολόγησή τους Στο δεύτερο κεφάλαιο περιγράφεται η αδρομερής μορφή του μοντέλου MIKE-SHE, η οποία χρησιμοποιήθηκε για την προσομοίωση. Για τις επιμέρους διαδικασίες επιλέχτηκαν οι εξής τρόποι υπολογισμού: η επιφανειακή ροή υπολογίζεται με την εξίσωση του Manning, η ροή στην ακόρεστη ζώνη με την μέθοδο του υδατικού ισοζυγίου (απλοποιημένη ροή μέσω μακροπόρων και μοντέλο κατείσδυσης Green and Ampt) και η υπεδάφια απορροή με τη μέθοδο του γραμμικού ταμιευτήρα. Στο τρίτο κεφάλαιο περιγράφεται η διαδικασία βαθμονόμησης των παραμέτρων του μοντέλου MIKE-SHE και παρουσιάζονται οι αναλύσεις ευαισθησίας των σημαντικότερων παραμέτρων του μοντέλου. Η ανάλυση ευαισθησίας για τον προσδιορισμό των τιμών των παραμέτρων του μοντέλου MIKE-SHE πραγματοποιήθηκε για την περίοδο 1984-1989, καθώς ο λόγος ΕΤ/Ρ δεν παρουσιάζει μεγάλες διακυμάνσεις για τις χρονιές αυτές. Οι βέλτιστες τιμές των παραμέτρων για την ρύθμιση του μοντέλου MIKE-SHE, οι οποίες προέκυψαν για την ανωτέρω χρονική περίοδο, εφαρμόστηκαν για την προσομοίωση της απορροής και τις υπόλοιπες χρονιές. Στο τέταρτο κεφάλαιο παρουσιάζονται τα αποτελέσματα του μοντέλου MIKE-SHE σε σύγκριση με εκείνα του μοντέλου βροχής-απορροής ENNS. Αρχικά, συγκρίνεται η συνολική απορροή των δυο μοντέλων μεταξύ τους και με την μετρημένη και εν συνεχεία, συγκρίνονται οι επιμέρους υδρολογικές συνιστώσες του υδρολογικού ισοζυγίου των δυο μοντέλων. Στο τελευταίο κεφάλαιο, παρουσιάζονται συνοπτικά τα συμπεράσματα, τα οποία εξήχθησαν από την σύγκριση των δυο μοντέλων αλλά και από την γενική συμπεριφορά του μοντέλου MIKE-SHE. / The subject of my thesis is the application of the rainfall-runoff model MIKE-SHE in the mountainous part of Glafkos’s basin. The aim of this study is to calibrate the model and to compare the simulations of MIKE-SHE with corresponding simulations of ENNS (Nachtnebel et al., 1993). The simulations with ENNS have been presented by Kaleris and Langousis (2012). Specifically, in the first chapter the study area and its characteristics (morphology, geometry, geology), the available data for the runoff simulations (rainfall, temperature, measured runoff) and their evaluation are presented. In the second chapter is described the structure of the model MIKE-SHE. For the simulation of the individual processes the following concepts are used in MIKE-SHE: the surface flow is calculated using the equation of Manning and for the flow in the unsaturated zone the two-layer water balance method (simplified flow through macropores and infiltration model Green and Ampt) has been used. Finally, for the subsurface runoff the linear reservoir’s equations has been used. In the third chapter the parameters varied in the calibration of MIKE-SHE and the sensitivity of the runoff with respect to these parameters have been presented. By means of the sensitivity analysis the most important parameters, which have been varied for the model calibration have been selected. The fourth chapter presents the results of the MIKE-SHE calibration and their comparison with the results of the rainfall-runoff model ENNS. Particularly, this chapter contains the comparison of the simulated hydrographs of the total runoff with the corresponding measured hydrographs and the hydrographs resulting from ENNS, as well as the comparison of the other water budget components resulting from the two models. The last chapter summarizes the conclusions which are drawn from the comparison of the two models and the evaluation of the behavior of the model MIKE-SHE.

The Florida Everglades has a long history of anthropogenic changes which have impacted the quantity and quality of water entering the system. Since the construction of Tamiami Trail in the 1920's, overland flow to the Florida Everglades has decreased significantly, impacting ecosystems from the wetlands to the estuary. The MIKE Marsh Model of Everglades National Park (M3ENP) is a numerical model, which simulates Everglades National Park (ENP) hydrology using MIKE SHE/MIKE 11software. This model has been developed to determine the parameters that effect Everglades hydrology and understand the impact of specific flow changes on the hydrology of the system. As part of the effort to return flows to the historical levels, several changes to the existing water management infrastructure have been implemented or are in the design phase. Bridge construction scenarios were programed into the M3ENP model to review the effect of these structural changes and evaluate the potential impacts on water levels and hydroperiods in the receiving Northeast Shark Slough ecosystem. These scenarios have shown critical water level increases in an area which has been in decline due to low water levels. Results from this work may help guide future decisions for restoration designs. Excess phosphorus entering Everglades National Park in South Florida may promote the growth of more phosphorus-opportunistic species and alter the food chain from the bottom up. Two phosphorus transport methods were developed into the M3ENP hydrodynamic model to determine the factors affecting phosphorus transport and the impact of bridge construction on water quality. Results showed that while phosphorus concentrations in surface waters decreased overall, some areas within ENP interior may experience an increase in phosphorus loading which the addition of bridges to Tamiami Trail. Finally, phosphorus data and modeled water level data was used to evaluate the spectral response of Everglades vegetation to increasing phosphorus availability using Landsat imagery.

An integrated surface-subsurface hydrological model of Everglades National Park (ENP) was developed using MIKE SHE and MIKE 11 modeling software. The model has a resolution of 400 meters, covers approximately 1050 square miles of ENP, includes 110 miles of drainage canals with a variety of hydraulic structures, and processes hydrological information, such as evapotranspiration, precipitation, groundwater levels, canal discharges and levels, and operational schedules. Calibration was based on time series and probability of exceedance for water levels and discharges in the years 1987 through 1997. Model verification was then completed for the period of 1998 through 2005. Parameter sensitivity in uncertainty analysis showed that the model was most sensitive to the hydraulic conductivity of the regional Surficial Aquifer System, the Manning's roughness coefficient, and the leakage coefficient, which defines the canal-subsurface interaction. The model offers an enhanced predictive capability, compared to other models currently available, to simulate the flow regime in ENP and to forecast the impact of topography, water flows, and modifying operation schedules.

Currently there are urgent water related problems, such as use of groundwater and surface water resources, which need a more integrated view on the hydraulic cycle and how the different processes interact with each other. This has led to new ways of thinking in management of watersheds, which sparked the creation of new integrated tools for flow characterization. Characterization of a watersheds flow is an important step in future research regarding water quality and climate change issues. The Krycklan catchment, located in the northern part of Sweden, has been under research for many years. With a great deal of measurements regarding stream water chemistry as well as climate measurements (evaporation, transpiration and temperature), the catchment has great potential regarding solute transportation and climate change investigation. This thesis was made to aid in future research by characterization of the catchments groundwater and surface flow, by the use of an integrated model software tool, MIKE-SHE. The model have been calibrated and validated with the help of real time observed measurements at Krycklan combined with model data from SMHI:s HYPE-model. Throughout the calibration it was discovered that the hydraulic conductivities were important for the surface and groundwater interaction, regulating base flow as well as peak flows. The shape and timing of the spring flood was also affected by the snow melt while the summer peaks for the upstream rivers, probably due to the relatively large difference in topography elevation, were more affected by the representation of the topography created by the grid size. A smaller grid-size resulted in a finer representation of the topography, which resulted in a quicker runoff to the upstream rivers without an increase of base flow. This gave better fitted hydrographs of the flows in the upstream rivers compared to observed measurements. The final model created was able to capture the discharge-hydrograph and groundwater fluctuations with small error and high correlation coefficients compared to observed data and model data from SMHI. The results as well as the calibration process helped with a deeper understanding of the modeling tool itself as well. Future improvements that can be considered are to introduce new calibration data and the use of an even smaller grid size. This can improve the understanding of the catchment as well as the representation of the flow in the upstream rivers. However, the effects of a smaller grid size must be reflected upon. The model will most likely become more unstable and the run time of the model will greatly increase. One suggestion to solve this issue is to look into a sub-catchment to reduce these complications.

An increase in the frequency and intensity of storm events is predicted by numerous climate researchers for the north of Europe. Not only this but also landuse change in form of clear-cutting can have an impact on the discharge of rivers and with that on road drainage structures. Extensive societal costs can be the consequences of blockage and underdimensioned structures. Hydrological models are powerful instruments that can be used to assess the future dimension requirements for road drainage structures especially in specifically vulnerable areas. In this thesis the hydrological model MIKE SHE was set up to study the discharge and water level at two pipe bridges and one culvert within the catchment of the river Hakerud in Västra Götaland, Sweden. Three scenarios were considered including a changing climate until 2050 and 2100 and a clear-cut scenario aiming to find out if the current design is sufficient for the future. This model can be used as an example model set-up for similar studies taking the recommendations of the experience gained in this thesis into consideration. For the Swedish Transport Administration further studies on this basis can contribute to decision making on the dimensioning of road drainage structures in the future to ensure a safe and robust infrastructural system.

The natural movement of water is known as the hydrological cycle. Many different factors affect the hydrological cycle and the availability of freshwater. The availability of freshwater is essential for many human activities. Three of the UN SDG’s (Sustainable Development Goals), number 2, 6 and 7, directly or indirectly relate to freshwater supplies. SDG number 2, zero hunger; a part of fulfilling this goal is to have enough available freshwater to irrigate crops. SDG number 6 is about access to clean water and sanitation. It is possible to desalinate saline water, treat unclean water or transport water long distances, but these are often costly and energy demanding processes. Therefore, it is important to manage the freshwater supplies that are available wisely. Access to clean and affordable energy is SDG number 7. One source of clean and affordable energy is hydropower, in order to produce electricity in a hydropower plant, plenty of water and a change in potential energy is needed . To be able to fulfil all these goals, it is important to include all of the perspectives when making policies regarding agriculture, building hydropower plants or making big infrastructure changes. The complex relationships between the different areas of interest can make it complicated to analyse the effects of a change made in any area. The concept of connecting different perspectives is called Nexus. This aim of this thesis was to evaluate different computer-based hydrological modelling tools, and how they can be used for Nexus assessments. This was done by performing a market research, choosing two tools for further assessment, creating evaluation criteria and perform a case study on a watershed in Uganda. The case study results and the evaluation criteria were then compared to an existing model in WEAP. The two selected hydrological modelling tools were MIKE SHE and SWAT. These two modelling tools were evaluated based on specified evaluation criteria. In the case study they modelled the same area in Kamwenge, Uganda. The output of the models was compared and calibrated against observed flow in the river at the outlet of the watershed. The results of the case study were incomplete since the MIKE SHE model was not calibrated successfully. The different models have different strengths. The format of output data and flexibility of the program is superior in MIKE SHE, while SWAT is more intuitive and demands less computer power. Over all SWAT is easier to use and model in for a novice user, while MIKE SHE requires more expertise in order to run a successful model. SWAT is able to model more of the Nexus perspectives and are therefore the preferred model. / Många faktorer påverkar tillgängligheten av sötvatten som är väsentligt för många mänskliga aktiviteter. Tre av FN:s globala hållbarhets mål, nummer 2, 6 och 7 relaterar direkt eller indirekt till tillgång till sötvatten. Mål nummer 2, ingen hunger; en del av att uppfylla detta mål är att det måste finnas vatten för att bevattna grödor. Mål nummer 6, tillgång till rent vatten och sanitet; det är möjligt att rena vatten eller att transportera det längre distanser, men det är ofta energikrävande och kostsamt. Därför är det viktigt att förvalta tillgängliga sötvatten resurser klokt. Hållbar energi för alla är mål nummer 7. En källa till hållbar och ren energi är vattenkraft, för att producera vattenkraft behövs en skillnad i potentiell energi och mycket vatten. För att kunna uppfylla alla dessa mål är det viktigt att inkludera alla perspektiv när man bestämmer policys för jordbruk, bygger vattenkraftverk eller gör andra stora ändringar i infrastrukturen. De komplicerade förhållandena mellan dessa olika intresseområden för vatten kan göra det svårt att förutse hur en förändring i en av dem påverkar de andra. Konceptet att koppla ihop olika perspektiv kallas Nexus. Målet med denna uppsats var att utvärdera olika hydrologiska modelleringsverktyg och hur de kan användas för Nexus bedömning. Det gjordes genom att en marknadsundersökning genomfördes och två modelleringsverktyg valdes ut. De två utvalda modelleringsverktygen var MIKE SHE och SWAT. Dessa två verktyg utvärderades baserat på specificerade kriterier. I fallstudien modellerade båda modelleringsverktygen samma område i Kamwenge, Uganda. De båda modellerna kalibrerades mot observerade utflöden från avrinningsområdet. Resultaten jämfördes med en existerande modell i WEAP. Resultaten från fallstudien är ofullständiga då kalibreringen för MIKE SHE modellen inte lyckades.