Submitted by Isaac Francisco de Souza Dias (isaac.souzadias@ufpe.br) on 2016-07-07T18:03:04Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Tese_Victor_Versão_Final.pdf: 12070696 bytes, checksum: 5580364541fc1e8bdf9f1bc84dc852fa (MD5) / Made available in DSpace on 2016-07-07T18:03:04Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Tese_Victor_Versão_Final.pdf: 12070696 bytes, checksum: 5580364541fc1e8bdf9f1bc84dc852fa (MD5) Previous issue date: 2016-02-03 / FACEPE / As limitações de dados pontuais para a estimativa da recarga subterrânea em grandes áreas ainda é um grande desafio para uma boa gestão desse recurso hídrico, principalmente em regiões semiáridas. Por causa da escassez de dados observados, a abordagem desta pesquisa estabelece uma integração entre um conjunto de variáveis do balanço hídrico, obtidas a partir de imagens de satélites, para estimar a distribuição espacial da recarga das águas subterrâneas na bacia hidrográfica do rio Ipanema (BHRI), localizada no estado de Pernambuco, Nordeste do Brasil. Os dados de sensoriamento remoto empregados incluem mapas mensais (2011-2012) de precipitação, escoamento superficial e evapotranspiração, utilizados como entradas para a aplicação do método do balanço hídrico (pixel a pixel) em um Sistema de Informação Geográfica (SIG). A precipitação utilizada foi derivada do satélite TRMM (3B43.v7) e seguiu o mesmo padrão médio mensal observado em 15 estações pluviométricas distribuídas pela área de estudo (CC = 0,93 e REQM = 17,1 mm), com estimativas médias anuais de 894,3 (2011) e 300,7 mm (2012). O escoamento superficial, adquirido pelo método SCS-CN a partir de informações dos solos da região e imagem do sensor TM, foi equivalente a 29% da precipitação registrada pelo TRMM durante os dois anos do estudo. Já a evapotranspiração real, obtida pela aplicação do SEBAL em imagens do sensor MODIS, apresentou valores médios anuais de 1.190 (2011) e 1.072 mm (2012). Os resultados do balanço hídrico mostraram que a recarga subterrânea na BHRI apresentou uma grande diferença interanual, caracterizada pelos regimes pluviométricos distintos, com médias de 28,1 (2011) e 4,9 (2012) mm ano-1. Essas recargas foram concentradas principalmente entre os meses de janeiro a julho nas regiões compostas por sedimentos aluviais e outros solos de alta permeabilidade. As aproximações da recarga subterrânea por sensoriamento remoto foram comparadas ao método WTF (Water Table Fluctuation) em uma área específica de aluvião na BHRI. As estimativas realizadas pelas duas metodologias apresentaram boa concordância anual, com valores médios de 154,6 (WTF) e 120,9 (balanço hídrico) mm em 2011, que correspondem a 14,89 e 13,12% das precipitações registradas pelo pluviômetro e pelo TRMM, respectivamente. Para o ano de 2012, apenas a metodologia WTF registrou uma recarga muito baixa de 15,9 mm. Como os estudos referentes ao tema ainda são incipientes, os valores gerados nesta tese fornecem uma boa percepção do potencial do sensoriamento remoto para avaliar as taxas desse importante componente do balanço hídrico na BHRI. / The limitations of data points to estimate the groundwater recharge over large areas are still a challenge for a good management of water resource, especially in semi-arid regions. Due to the deficiency of observed data, the approach of this research establishes an integration of hydrological cycle variables obtained from satellite images to estimate the spatial distribution of groundwater recharge in the Ipanema basin river (BHRI), located in the Pernambuco state, northeastern of Brazil. The remote sensing data used, which include monthly maps (2011-2012) of rainfall, runoff and evapotranspiration were used as input to apply the water balance method (pixel by pixel) in a Geographic Information System (GIS). The rainfall used was derived from the TRMM satellite (3B43.v7) and has the same monthly average observed temporal distribution in 15 rain gauges distributed over the study area (CC = 0.93 and RMSE = 17.1 mm), with annual average estimates of 894.3 (2011) and 300.7 mm (2012). The runoff acquired by SCS-CN method from information soil of the region and TM sensor image was equivalent to 29% of the TRMM rainfall registered during the two years of the study. The actual evapotranspiration obtained by the SEBAL application in MODIS images presented annual average of 1,190 (2011) and 1,072 (2012) mm. The results of the water balance showed a large interannual difference in the BHRI groundwater recharge, characterized by different rainfall regimes with averages of 28.1 (2011) and 4.9 (2012) mm year-1. These recharges were mainly concentrated between January to July in the regions with alluvial sediments and others high permeability soils. The groundwater recharge approach by remote sensing was compared to the WTF method (Water Table Fluctuation) in a specific area of alluvium in the BHRI. The estimates performed by the two methods showed good annual agreement, with mean values of 154.6 (WTF) and 120.9 (water balance) mm in 2011, corresponding to 14.89 and 13.12% of rainfall recorded at the rain gauge and TRMM, respectively. For the second year, just WTF method recorded a very low recharge of 15.9 mm. Studies related to the groundwater recharge involving remote sensing are incipient and the values generated in this thesis provide a good perception of the methodology to evaluate the rates of this important component of the water balance in the BHRI.

Prior to using hydraulic and spatially distributed modelling softwares, the theory of the unit hydrograph was a commonly used tool for modelling of surface and runoff water. While distributed models often provide detailed results from extensive calculation durations, the unit hydrograph have been questioned for simplifying the physical characteristics of the watershed modelled. Typically, the unit hydrograph theory does not explicitly take the flow paths of the watershed in consideration during calculation. With the rise of geographical information systems, methods of deriving spatially distributed unit hydrographs have been developed. The aim of these have commonly been to find a spatially varied form of hydrological modelling, while still keeping the computation times low. The method is commonly built by calculating the travel time to the watershed outlet along the flow path. In this study, spatially distributed unit hydrographs are derived separately for the watershed’s pervious and impervious surfaces in a Python script using map algebra and the Esri’s Python wrapper module Arcpy. The travel times are generated from a velocity field calculated using Maidment and Olivera’s velocity equation. The velocity equation contains three unknown parameters; one for an average velocity and two calibration parameters. The excess precipitation is calculated of a 100 year return period Chicago Design Storm hyetograph using the SCS-CN method. The direct runoff hydrographs are calculated over three semi-urban watersheds in Smedby in southern Sweden, and the results are compared to MIKE 21 hydrograph data of each corresponding watershed and rain input. The result obtained showed to replicate the hydrograph response quite well, but only if the unknown parameters in the velocity equation were calibrated to match the MIKE 21 data. The unknown parameters of the velocity equations produces uncertainties of using the method without calibration data, which implies that the script is not well adapted to use for modelling predictions. It may be of interest to calculate the travel times of the locations within the watershed using a different formula. The script tool could be tested using different design storms as input, and areas of different characteristics compared to Smedby could be tested. / Innan det blev vanligt att använda hydrauliska och rumsliga modellerings- mjukvaror användes ofta teorin bakom enhetshydrografen för modellering av avrinning. Medan de rumsliga mjukvarorna ofta erbjuder detaljerade resultat till priset av långa beräkningstider, har enhetshydrografen ifrågasatts för att förenkla den fysiska karaktären av avrinningsområdet. Typiskt sett tar inte enhetshydrografen avrinningsområdets flödesvägar direkt i hänseende vid beräkning. Utveckling och ökad tillgänglighet av geografiska informations- system förenklade möjligheterna att utveckla beräkning av enhetshydrografer som tar hänsyn till avrinningsområdets karaktär, typiskt sett genom att beräkna rinntiden från varje läge i avrinningsområdet, längs rinnvägarna och till utloppet. I den här studien beräknas spatiala enhetshydrografer separat för avrinningsområdets hårdgjorda och icke hårdgjorda ytor, genom att utveckla ett Python skript med hjälp av karalgebra och Esri’s wrapper modul ArcPy. Rinntiderna från olika lägen i avrinningsområdet beräknas med Maidments och Oliveras formel för hastighet, vilken innehåller okända parametrar för en uppskattad medelhastighet samt två kalibreringsparametrar. Effektivt regn från ett Chicago Design Storm regn med en återkomsttid på 100 år beräknas med hjälp av SCS-CN metoden. Hydrograferna för direkt avrinning faltas för tre semi-urbana avrinningsområden i Smedby i södra Sverige för att sedan jämföras mot MIKE 21 genererad hydrograf data för respektive motsvarade avrinningsområde. Hydrografdata producerat av MIKE 21 har tagits fram med lika CDS-regn data som input. Resultatet visar att hydrografer snarlika MIKE 21 hydrograferna kan tas fram med Maidments spatialt fördelade enhetshydrograf, om de okända parametrarna i Maidments formel kalibrerades mot MIKE 21 data. Utan kalibreringsdata för att bestämma de okända parametrarna kan resultatet anses vara mycket osäkert, vilket antyder att Python skriptet ej bör användas för använda metoden för att förutspå responser av regnevent. Andra beräkningar än Maidments ekvation kan vara av intresse att implementera. Olika typer av regninput samt spatial data över andra platser än Smedby kan vara av intresse att testa Python skriptet för.

<p>Society-induced changes to the environment are altering the effectiveness of existing management strategies for sustaining natural and agricultural ecosystem productivity. At the watershed scale, natural and agro-ecosystems represent complex spatiotemporal stochastic processes. In time, they respond to random rainfall events, evapotranspiration and other losses that are spatially variable because of heterogeneities in soil properties, root distributions, topography, and other factors. To quantify the environmental impact of anthropogenic activities, it is essential that we characterize the evolution of space and time patterns of ecosystem fluxes (e.g., energy, water, and nutrients). Such a characterization then provides a basis for assessing and managing future anthropogenic risks to the sustainability of ecosystem productivity.</p><p>To characterize the space and time evolution of watershed scale processes, this dissertation introduces a mean field approach to watershed hydrology. Mean field theory (also known as self-consistent field theory) is commonly used in statistical physics when modeling the space-time behavior of complex systems. The mean field theory approximates a complex multi-component system by considering a lumped (or average) effect of all individual components acting on a single component. Thus, the many body problem is reduced to a one body problem. For watershed hydrology, a mean field theory reduces the numerous point component effects to more tractable watershed averages resulting in a consistent method for linking the average watershed fluxes (evapotranspiration, runoff, etc.) to the local fluxes at each point.</p><p>The starting point for this work is a general point description of the soil moisture, rainfall, and runoff system. For this system, we find the joint PDF that describes the temporal variability of the soil water, rainfall, and runoff processes. Since this approach does not account for the spatial variability of runoff, we introduce a probabilistic storage (ProStor) framework for constructing a lumped (unit area) rainfall-runoff response from the spatial distribution of watershed storage. This framework provides a basis for unifying and extending common event-based hydrology models (e.g. Soil Conservation Service curve number (SCS-CN) method) with more modern semi-distributed models (e.g. Variable Infiltration Capacity (VIC) model, the Probability Distributed (PDM) model, and TOPMODEL). In each case, we obtain simple equations for the fractions of the different source areas of runoff, the spatial variability of runoff and soil moisture, and the average runoff value (i.e., the so-called runoff curve). Finally, we link the temporal and spatial descriptions with a mean field approach for watershed hydrology. By applying this mean field approach, we upscale the point description with the spatial distribution of soil moisture and parameterize the numerous local interactions related to lateral fluxes of soil water in terms of its average. With this approach, we then derive PDFs that represent the space and time distribution of soil water and associated watershed fluxes such as evapotranspiration and runoff.</p> / Dissertation

Low relief, heavily human-impacted landscapes like those of the Prairies in south-central Canada have received little attention in previous hydrological research. Here, the rainfall-runoff relationship in the context of both a field-based investigation and an empirical model is examined in an effort to provide insight into Prairie hydrology. Rainfall and water level data were collected for nested sub-watersheds of the Catfish Creek watershed, a 642 km2, near-level, mixed land use and engineered Prairie watershed. First, the dataset is examined for runoff controls. Second, the history of the United States Curve Number Method is reviewed and its initial abstraction ratio examined against collected field data to determine the applicability of a single, constant ratio to Prairie landscapes. Overall, the results indicate that Prairie runoff generation processes differ significantly from those of humid, pristine catchments of higher relief and a conceptual model is proposed with that regards.

A escassez de dados hidrológicos no Brasil é um problema recorrente em muitas regiões, principalmente em se tratando de dados hidrométricos, produção de sedimentos e qualidade da água. A pesquisa por modelos de bacias hidrográficas tem aumentado nas últimas décadas, porém, a estimativa de dados hidrossedimentológicos a partir de modelos mais sofisticados demanda de grande número de variáveis, que devem ser ajustadas para cada sistema natural, o que dificulta a sua aplicação. O objetivo principal desta tese foi avaliar diferentes ferramentas de modelagem utilizadas para a estimativa da vazão, produção de sedimentos e qualidade da água e, em particular, comparar os resultados obtidos de um modelo hidrológico físico semi-distribuído, o Soil Water Assessment Tool (SWAT) com os resultados obtidos a partir de modelos hidrológicos concentrados, com base na metodologia do número da curva de escoamento do Soil Conservation Service (SCS-CN) e no modelo Generalized Watershed Loading Function (GWLF). Buscou-se avaliar e apresentar em quais condições o uso de cada modelo deve ser recomendado, ou seja, quando o esforço necessário para executar o modelo semi-distribuído leva a melhores resultados efetivos. Em relação à simulação da vazão, os resultados dos dois modelos foram altamente influenciados pelos dados de precipitação, indicando que existem, possivelmente, falhas ou erros de medição que poderiam ter influenciado negativamente os resultados. Portanto, foi proposto aplicar o modelo semi-distribuído com dados de precipitação interpolados (DPI) de alta resolução para verificar a eficiência de seus resultados em comparação com os resultados obtidos com a utilização dos dados de precipitação observados (DPO). Para simulação da produção de sedimentos, e das concentrações de nitrogênio e fósforo, o SWAT realiza uma simulação hidrológica mais detalhada, portanto, fornece resultados ligeiramente melhores para parâmetros de qualidade da água. O uso do modelo semi-distribuído também foi ampliado para simular uma bacia hidrográfica sob a influência do reservatório, a fim de verificar a potencialidade do modelo para esse propósito. Os modelos também foram aplicados para identificar quais os impactos potenciais das mudanças no uso do solo previstas e em andamento. Os cenários estudados foram: I &#8211; cenário atual, II &#8211; cenário tendencial, com o aumento da mancha urbana e substituição do solo exposto e de parte da mata nativa por uso agrícola; III &#8211; cenário desejável, complementa o crescimento urbano tendencial com aumento de áreas de reflorestamento. As metodologias foram aplicadas em duas bacias hidrográficas localizadas no Sudeste do Brasil. A primeira é a bacia do rio Jacaré-Guaçu, incluída na Unidade de Gerenciamento de Recursos Hídricos 13 (UGRHI-13), a montante da confluência do rio das Cruzes, com uma área de 1934 km2. O segundo caso de estudo, é a bacia do rio Atibaia, inserida na UGRHI-5, tem uma área de 2817,88 km2 e abrange municípios dos estados de São Paulo e Minas Gerais. Como principal conclusão, o desempenho do modelo semi-distribuído para estimar a produção de sedimentos, e as concentrações de nitrogênio e fósforo foi ligeiramente melhor do que as simulações do modelo concentrado SCS-CN e GWLF, mas essa vantagem pode não compensar o esforço adicional de calibrá-lo e validá-lo. / The lack of hydrological data in Brazil is a recurrent problem in many regions, especially in hydrometric data, sediment yield and water quality. The research by simplified models has increased in the last decades, however, the estimation of hydrossedimentological data from these more sophisticated models demands many variables, which must be adjusted for each natural system, which makes it difficult to apply. At times it is necessary to respond quickly without much precision in the results, in these situations, simpler models with few parameters can be the solution. The objective of this research is to evaluate different modelling tools used estimate streamflow, sediments yield and nutrients loads values, and namely to compare the results obtained from a physically-based distributed hydrological model (SWAT) with the results from a lumped hydrological, the Soil Conservation Service (SCS-CN) and the Generalized Watershed Loading Function (GWLF) model. Both models use the curve number (CN) concept, determined from land use, soil hydrologic group and antecedent soil moisture conditions and were run with a daily time step. We are particularly interested in understanding under which conditions the use of each model is to be recommended, namely when does the addition effort required to run the distributed model leads to effective better results. The input variables and parameters of the lumped model are assumed constant throughout the watershed, while the SWAT model performs the hydrological analysis at a small unit level, designated as hydrological response units (HRUs), and integrates the results at a sub-basin level. In relation to the flow simulation, the results of the two models were highly influenced by the rainfall data, indicating that, possibly, faults or measurement errors could have negatively influenced the results. Therefore, it was proposed to apply the distributed model with high-resolution grids of daily precipitation to verify the efficiency of its results when compared to rainfall data. For simulation of sediment, nitrogen and phosphorus, SWAT performs a more detailed simulation and thus provides slightly better results. The use of the SWAT was also extended to simulate the influence of reservoir, in order to verify the potentiality of the model, in relation to the simulation. The models also were used to identify which are potential impacts of the ongoing land use changes. The scenarios were: I - Current scenario, II - trend scenario, with the increase of urban land and replacement of the exposed soil and part of the native forest by agricultural use; III - desirable scenario complements the trend urban growth with the replacement of exposed soil and part of the agricultural use by reforestation. The methodologies were applied on two watersheds located in the Southeast of Brazil. The first one is the Jacaré-Guaçu river basin, included in the Water Resources Management Unit 13 (UGRHI-13), upstream of Cruzes river confluence, with an area of 1934 km2. The second watershed is the Atibaia River Basin, a part of Water Resources Management Unit 5 (UGRHI-5). It has an area of 2817.88 km2 and covers municipalities of the states of São Paulo and Minas Gerais.

A escassez de dados hidrológicos no Brasil é um problema recorrente em muitas regiões, principalmente em se tratando de dados hidrométricos, produção de sedimentos e qualidade da água. A pesquisa por modelos de bacias hidrográficas tem aumentado nas últimas décadas, porém, a estimativa de dados hidrossedimentológicos a partir de modelos mais sofisticados demanda de grande número de variáveis, que devem ser ajustadas para cada sistema natural, o que dificulta a sua aplicação. O objetivo principal desta tese foi avaliar diferentes ferramentas de modelagem utilizadas para a estimativa da vazão, produção de sedimentos e qualidade da água e, em particular, comparar os resultados obtidos de um modelo hidrológico físico semi-distribuído, o Soil Water Assessment Tool (SWAT) com os resultados obtidos a partir de modelos hidrológicos concentrados, com base na metodologia do número da curva de escoamento do Soil Conservation Service (SCS-CN) e no modelo Generalized Watershed Loading Function (GWLF). Buscou-se avaliar e apresentar em quais condições o uso de cada modelo deve ser recomendado, ou seja, quando o esforço necessário para executar o modelo semi-distribuído leva a melhores resultados efetivos. Em relação à simulação da vazão, os resultados dos dois modelos foram altamente influenciados pelos dados de precipitação, indicando que existem, possivelmente, falhas ou erros de medição que poderiam ter influenciado negativamente os resultados. Portanto, foi proposto aplicar o modelo semi-distribuído com dados de precipitação interpolados (DPI) de alta resolução para verificar a eficiência de seus resultados em comparação com os resultados obtidos com a utilização dos dados de precipitação observados (DPO). Para simulação da produção de sedimentos, e das concentrações de nitrogênio e fósforo, o SWAT realiza uma simulação hidrológica mais detalhada, portanto, fornece resultados ligeiramente melhores para parâmetros de qualidade da água. O uso do modelo semi-distribuído também foi ampliado para simular uma bacia hidrográfica sob a influência do reservatório, a fim de verificar a potencialidade do modelo para esse propósito. Os modelos também foram aplicados para identificar quais os impactos potenciais das mudanças no uso do solo previstas e em andamento. Os cenários estudados foram: I &#8211; cenário atual, II &#8211; cenário tendencial, com o aumento da mancha urbana e substituição do solo exposto e de parte da mata nativa por uso agrícola; III &#8211; cenário desejável, complementa o crescimento urbano tendencial com aumento de áreas de reflorestamento. As metodologias foram aplicadas em duas bacias hidrográficas localizadas no Sudeste do Brasil. A primeira é a bacia do rio Jacaré-Guaçu, incluída na Unidade de Gerenciamento de Recursos Hídricos 13 (UGRHI-13), a montante da confluência do rio das Cruzes, com uma área de 1934 km2. O segundo caso de estudo, é a bacia do rio Atibaia, inserida na UGRHI-5, tem uma área de 2817,88 km2 e abrange municípios dos estados de São Paulo e Minas Gerais. Como principal conclusão, o desempenho do modelo semi-distribuído para estimar a produção de sedimentos, e as concentrações de nitrogênio e fósforo foi ligeiramente melhor do que as simulações do modelo concentrado SCS-CN e GWLF, mas essa vantagem pode não compensar o esforço adicional de calibrá-lo e validá-lo. / The lack of hydrological data in Brazil is a recurrent problem in many regions, especially in hydrometric data, sediment yield and water quality. The research by simplified models has increased in the last decades, however, the estimation of hydrossedimentological data from these more sophisticated models demands many variables, which must be adjusted for each natural system, which makes it difficult to apply. At times it is necessary to respond quickly without much precision in the results, in these situations, simpler models with few parameters can be the solution. The objective of this research is to evaluate different modelling tools used estimate streamflow, sediments yield and nutrients loads values, and namely to compare the results obtained from a physically-based distributed hydrological model (SWAT) with the results from a lumped hydrological, the Soil Conservation Service (SCS-CN) and the Generalized Watershed Loading Function (GWLF) model. Both models use the curve number (CN) concept, determined from land use, soil hydrologic group and antecedent soil moisture conditions and were run with a daily time step. We are particularly interested in understanding under which conditions the use of each model is to be recommended, namely when does the addition effort required to run the distributed model leads to effective better results. The input variables and parameters of the lumped model are assumed constant throughout the watershed, while the SWAT model performs the hydrological analysis at a small unit level, designated as hydrological response units (HRUs), and integrates the results at a sub-basin level. In relation to the flow simulation, the results of the two models were highly influenced by the rainfall data, indicating that, possibly, faults or measurement errors could have negatively influenced the results. Therefore, it was proposed to apply the distributed model with high-resolution grids of daily precipitation to verify the efficiency of its results when compared to rainfall data. For simulation of sediment, nitrogen and phosphorus, SWAT performs a more detailed simulation and thus provides slightly better results. The use of the SWAT was also extended to simulate the influence of reservoir, in order to verify the potentiality of the model, in relation to the simulation. The models also were used to identify which are potential impacts of the ongoing land use changes. The scenarios were: I - Current scenario, II - trend scenario, with the increase of urban land and replacement of the exposed soil and part of the native forest by agricultural use; III - desirable scenario complements the trend urban growth with the replacement of exposed soil and part of the agricultural use by reforestation. The methodologies were applied on two watersheds located in the Southeast of Brazil. The first one is the Jacaré-Guaçu river basin, included in the Water Resources Management Unit 13 (UGRHI-13), upstream of Cruzes river confluence, with an area of 1934 km2. The second watershed is the Atibaia River Basin, a part of Water Resources Management Unit 5 (UGRHI-5). It has an area of 2817.88 km2 and covers municipalities of the states of São Paulo and Minas Gerais.

The purpose of the thesis is to characterize flood events within the agricultural fields of flooding Pampa in Argentina. The characterization divides the flat landscape into flood prone areas and endeavour at linking driving factors to flood response based on past events. The characterization is based on information freely available from remote sensing (satelliteimages, digital elevation, and estimated rain data), from precipitation data from a weatherstation and from field measurements carried out with Universidad Nacional de La Plata. The main research question is: Which are the driving factors contributing to the flooding? Data from remote sensing was used to visualize previous areal water extents, to calculate the topographic wetness index, the upslope areas for the field study sites and for a precipitationtrend analysis. Furthermore, data from remote sensing was used to replace missing days of rain data from the weather station. The complemented rain data was compared with the water extent for the events. Relationships between event precipitation, previous precipitation, land-use, and surface runoff was evaluated with the Soil Conservation-Curve Number method, SCS-CN, and the runoff coefficients for different antecedent conditions were calculated. The precipitation data and the satellite images showing water extents were also used to calculatethe 100-year and 20-year storm- and flood event. The measured infiltration capacity was used as input data in the SCS-CN-method to calculate the surface runoff and the measured soilmoisture was used to verify results from the Topographic Wetness Index, TWI, map. The flood risk areas are visualized with satellite images and the calculated Modified Normalized Difference Water Index. The TWI also visualizes the more flood prone or wetter areas and delineates the lower depressions where soil moisture was also measured to be higher, however not significantly. With the available satellite images within the study results indicate that floods are more common wintertime and that great flood events cannot be foreseen with only antecedent precipitation and event precipitation with the SCS-CN method. However, the events in the study with larger water extents, had high precipitation. No clear correlation between water extents from satellite images calculated by Instituto Nacional de Tecnología Agropecuaria, and estimated surface runoff from the SCS-CN method could be seen. However, the obtained runoff coefficients from the SCS-CN method can be used for estimating surface runoff for future storm events were higher Antecedent Moisture Condition, AMC, and low infiltration capacities increases surface runoff. The infiltration capacity of the studied fields is approximately 16 mm/hour and hence not alone a driving factor causing inundation since the soil can absorb, for example, a 20-year storm event of 125 mm/day. However, that is not the case since a 20-year storm flood has covered 9 % of the area around Don Joaquin and El Amanecer with water. No seasonal precipitation trends can be seen in Punta Indio during the last 40 years analysing precipitation data from remote sensing. In flooding Pampa the agricultural fields inundate almost on yearly basis in the depressionsdue to the gentle slopes and high intense precipitation (yearly maximum daily precipitation is always higher than 60 mm/day). To decrease the flood risk the management should ensure high vegetative cover which increases infiltration and balances the hydrological responses. / Syftet med studien är att karakterisera översvämningar inom jordbruket på Argentinska Pampas. Det platta landskapet mest översvämningsutsatta områden pekas ut och arbetet har fokuserat på att koppla landskapets utformning och regnmönster till översvämningarna. Karakteriseringen utgår ifrån information från satellitbilder och digitala höjddata, från nederbördsdata från den närmaste väderstationen som kompletterats med regndata från fjärranlyser och från fältmätningar utförda tillsammans med Universidad Nacional de La Plata. Den huvudsakliga frågan är: Vilka är de bidragande faktorerna till översvämningarna? Information från fjärranalyser användes för att visualisera tidigare översvämningar, för att beräkna det topografiska fuktighetsindexet, tillrinningsområdet för fältstudieplatserna och för en nederbördstrendanalys. Regndatan jämfördes med vattenarean under tidigare översvämningar. Sambanden mellan nederbörd, markanvändning och ytavrinning utvärderades med Soil Conservation-Curve Number metoden, SCS-CN, och avrinningskoefficienterna för olika nederbördsförhållanden beräknades. Nederbördsdata och satellitbilder som visar vattnets utbredning användes också för att beräkna magnituden av ett 100-årsregn och 20-årsregn samt utbredningen av en 100-årsöversvämning. Den i fält uppmätta infiltrationskapaciteten användes som indata i SCS-CN-metoden för att beräkna ytavrinning och den i fält uppmätta markfuktigheten för att verifiera resultat från GISanalysen av det topografiska fuktighetsindexet.' Översvämningsriskområden visualiserades i studien med satellitbilder och det modifierade normaliserade differens vattenindexet. Även det topografiska fuktighetsindexet visualiserar de mer översvämningsbenägna områdena och markerar vattnets väg där markfuktigheten också uppmättes vara högre, dock inte signifikant blötare än ovan liggande punkter. Analys av de tillgängliga satellitbilderna i studien visar att översvämningar är vanligare vintertid och att stora översvämningshändelser inte kan förutses enbart med de senaste dagarnas regnmängd och eventregnet med SCS-CN-metoden. Alla satellitbilder i studien med större vattentäckning kunde dock kopplas till stora regnmängder. Ingen tydlig korrelation mellan vattenutbredningen och uppskattad ytavrinning med SCS-CN-metoden kunde ses. De erhållna avrinningskoefficienterna från SCS-CN-metoden kan dock användas för att uppskatta risken för ytavrinning vid framtida regn där större regnmängder och låg infiltration ökar ytavrinningen. Fältens infiltrationskapacitet är cirka 16 mm/timme och därmed inte ensamt en drivande faktor till översvämningarna eftersom infiltrationskapaciteten är högre än exempelvis ett 20-årsregn (125 mm/dygn). Dock kan 20-årsregn täcka 9 % av området runt Don Joaquin och El Amanecer med vatten. Inga nederbördstrender kan ses i Punta Indio under de senaste 40 åren genom analys av nederbördsdata från fjärranalyser. I Pampa deprimida översvämmar jordbruksfälten nästan årligen i sänkorna på grund av den platta topografin och den höga intensiva nederbörden (den årliga maximala dagliga nederbörden är nästan alltid högre än 60 mm/dag). För att minska översvämningsriskerna bör lantbrukare säkerställa en hög vegetativ täckning som ökar infiltrationen, skyddar marken och balanserar de hydrologiska reaktionerna. / El propósito de la tesis es analizar los posibles eventos de inundación en un sector de la Pampa Deprimida en Argentina, dada la importancia productiva de la región. Se trabajó en los campos de la Universidad Nacional de La Plata con la dirección del curso de Edafología, de la Facultad de Ciencias Agrarias y Forestales. Se caracterizó la región en general y los campos en particular, utilizando información de acceso gratuito en la web, tales como imágenes satelitales, mapas de elevación digital e información meterologíca. Se utilizaron técnicas geomáticas para definir la evolución de agua en superficie mediante un análisis de la precipitación y coberturas de agua en imágenes satelitales obtenidas entre el 2000 y 2022 con la finalidad de calcular el Indice de Humedad Topográfico (TWI). Se establecen relaciones entre la precipitación, el manejo de los campos, la escorrentía superficial y las cuberturas de aguas. Se analizó la occurrencias de eventos de excesos hídricos. Se efectuaron ensayos de infiltración y el método Soil Conservation Service-Curve Number (SCS-CN) a fin de estimar la escorrentía superficial y las medidas de la humedad del suelo para verificar los resultados del mapa con el TWI. Las imágenes satélitales y el Modified Normalized Differential Water Index (MNDWI) calculado, permiten estimar las áreas más expuestas a inundaciones. El TWI permitió distinguir los sectores más altos y bajos mediante la medición de la humedad del suelo. Con los datos disponibles en este estudio, los resultados indican que las inundaciones son más frecuentes en invierno, y que los grandes eventos de inundación no se pueden predecir solo con registros de precipitación y el uso del método SCS-CN. No se pudo observar una correlación entre las extensiones de agua de las imágenes satelitales calculadas por Instituto Nacional de Tecnología Agropecuaria (INTA Clima y Agua, Castelar), y la escorrentía superficial estimada por el método SCS-CN. Sin embargo es possible encontrar una correspondencia entre las precipitaciones muy elevadas y la cobertura de agua. La occurencia de altas precipitaciones luego de un periodo lluvioso en un suelo con baja infiltración debido a una baja cobertura vegetal, aumenta la escorrentía superficial. La capacidad de infiltración del campo estudiado es de aproximadamente 16 mm/hora y un evento de lluvia extrema que se produce cada 20 años puede ser de 125 mm/día. Consecuentemente, no sería la baja infiltración la principal causa de la inundacion. No obstante, se aprecia que effectivamente un evento de 125 mm/día cubre 9 % del área en Don Joaquín y del El Amanecer. Con precipitaciones normales la cobertura es de aproximadamente 2 %. Cabe indicar que las precipitaciones registradas en la estación de Punta Indio durante los últimos 40 años, no manifiestan un comportamiento diferente en su occurencia y cantidad. En Pampa deprimida los campos se inundan frecuente, no solo debido a las precipitaciones locales y el amabiente de muy bajas pendientes. Los flujos de agua subterranea, aunque no se las pudo analizar en este estudio, también afuectuan las coberturas de agua. A fin de disminuirlos riesgos de inundación, el manejo debe garantizar una alta cobertura vegetal que aumente la infiltración y proteja al suelo y, de este modo, contribuir a controlar la natural dinámica hidrológica de la región en estudio. / Estudio del suelo, agua subterránea y vegetación, como base para definir ambientes de manejo en el partido de Magdalena