O aumento na utilização do sistema de gotejamento em grandes culturas como a cana-de-açúcar, visa minimizar perdas hídricas durante o processo de irrigação, principalmente em períodos de escassez hídrica ocorrida no país. Para atingir tal propósito, o dimensionamento correto desse sistema de irrigação é de fundamental importância, viabilizando o manejo adequado e uso de práticas para aplicação de fertilizantes (solutos), via água de irrigação (fertirrigação). Nesse sentido, são necessárias informações um pouco mais precisas sobre a dinâmica da água e dos solutos no solo, os quais estão relacionados com a distribuição desta solução em torno do emissor (gotejador). Assim sendo, o principal objetivo dessa pesquisa consistiu em avaliar o desempenho do modelo HYDRUS-2D nas simulações numéricas da formação do volume de solo molhado sob irrigação por gotejamento subsuperficial, em diferentes fases de desenvolvimento da cultura de cana-de-açúcar (perfilhamento, crescimento dos colmos e maturação), buscando-se comparar os resultados obtidos pelas simulações do modelo com aqueles obtidos em condições experimentais. Para tal, foram coletados dados de umidade volumétrica do solo e das concentrações de potássio no solo, pela Técnica da Reflectometria no Tempo (TDR), tornando possível a obtenção de dados em tempo real da distribuição da solução, como também, auxiliar na avaliação e performance do modelo matemático HYDRUS-2D. Assim sendo, a referida pesquisa foi dividida em duas etapas: Etapa 1) Coleta de dados das propriedades físico-hídricas do solo e da distribuição da água e do potássio mediante um arranjo experimental, distribuído em dois tratamentos, inteiramente casualizados, sendo três repetições e seis parcelas, dispostos da seguinte maneira, Tratamento 1 (T1): sem cultivo de cana-de-açúcar e com emissor de vazão de 4,0 L h-1, Tratamento 2 (T2): com cultivo de cana-de-açúcar, com emissor de vazão 4,0 L h-1 e na Etapa 2) Foi realizada a simulação numérica da distribuição da solução (água e potássio), pelo modelo HYDRUS-2D nos respectivos estágios de desenvolvimento do cultivo da cana-de-açúcar (citados anteriormente). O desempenho do modelo foi avaliado com base nos seguintes parâmetros estatísticos: Raiz do Erro Quadrático Médio (RMSE) e Erro Absoluto Médio (MAE). A partir dos resultados obtidos nos parâmetros estatísticos, os dados estimados pelo modelo HYDRUS-2D obtiveram uma boa concordância em relação aos dados observados do conteúdo de água e da concentração de potássio presente no perfil de solo. Diante disso, pôde-se concluir que o modelo HYDRUS-2D forneceu uma caracterização aceitável do volume de solo molhado nas diferentes fases de desenvolvimento da cana-de-açúcar e também sem a presença da cultura. / Drip irrigation systems are increasingly being used for such major crops as sugarcane to minimize water losses during irrigation. Saving water is becoming more and more important also in Brazil because of increasing water scarcity in the country. Proper design of a drip irrigation system is fundamental to implementation of optimal water and nutrient management practices, including possible application of fertilizers with the irrigation water (fertigation). This in turn requires reliable information about expected water and solute distributions in the soil profile around the emitters (drippers) during and after irrigation The main objective of this research was to use the HYDRUS-2D software package to estimate wetted soil volumes around the drippers during subsurface drip irrigation at different stages of sugarcane development (tillering, stalk growth, maturation), and to compare numerical results with experimental data. Field data collected for this purpose included soil moisture and potassium concentration distributions using Time Domain Reflectometry (TDR). Results made it possible to follow evolving solute concentration distributions around the drippers in real time, and to evaluate the performance of HYDRUS-2D. The research was divided into two steps: Step 1 involved collection of physical and hydraulic data of the soil, as well as of water and potassium distributions by means of a completely randomized experimental arrangement using two treatments, each with three replicates. Treatments 1 and 2 were for the scenarios without and with sugarcane cultivation, with both treatments having a flow emitter rate of 4.0 L h-1. Step 2 involved HYDRUS-2D simulations of the moisture and potassium concentration distributions around the drippers at different stages of sugarcane development. Model performance was evaluated using the following statistical parameters: Mean Squared Error Root (RMSE) and Mean Absolute Error (MAE). From the results obtained in the statistical parameters, HYDRUS-2D predictions obtained a good agreement with the observed data of water content and the potassium concentration in the soil profile. Therefore, it was concluded that HYDRUS-2D model provided an acceptable characterization of the wetted volume at different stages of development of sugarcane and also without the presence of culture.

O aumento na utilização do sistema de gotejamento em grandes culturas como a cana-de-açúcar, visa minimizar perdas hídricas durante o processo de irrigação, principalmente em períodos de escassez hídrica ocorrida no país. Para atingir tal propósito, o dimensionamento correto desse sistema de irrigação é de fundamental importância, viabilizando o manejo adequado e uso de práticas para aplicação de fertilizantes (solutos), via água de irrigação (fertirrigação). Nesse sentido, são necessárias informações um pouco mais precisas sobre a dinâmica da água e dos solutos no solo, os quais estão relacionados com a distribuição desta solução em torno do emissor (gotejador). Assim sendo, o principal objetivo dessa pesquisa consistiu em avaliar o desempenho do modelo HYDRUS-2D nas simulações numéricas da formação do volume de solo molhado sob irrigação por gotejamento subsuperficial, em diferentes fases de desenvolvimento da cultura de cana-de-açúcar (perfilhamento, crescimento dos colmos e maturação), buscando-se comparar os resultados obtidos pelas simulações do modelo com aqueles obtidos em condições experimentais. Para tal, foram coletados dados de umidade volumétrica do solo e das concentrações de potássio no solo, pela Técnica da Reflectometria no Tempo (TDR), tornando possível a obtenção de dados em tempo real da distribuição da solução, como também, auxiliar na avaliação e performance do modelo matemático HYDRUS-2D. Assim sendo, a referida pesquisa foi dividida em duas etapas: Etapa 1) Coleta de dados das propriedades físico-hídricas do solo e da distribuição da água e do potássio mediante um arranjo experimental, distribuído em dois tratamentos, inteiramente casualizados, sendo três repetições e seis parcelas, dispostos da seguinte maneira, Tratamento 1 (T1): sem cultivo de cana-de-açúcar e com emissor de vazão de 4,0 L h-1, Tratamento 2 (T2): com cultivo de cana-de-açúcar, com emissor de vazão 4,0 L h-1 e na Etapa 2) Foi realizada a simulação numérica da distribuição da solução (água e potássio), pelo modelo HYDRUS-2D nos respectivos estágios de desenvolvimento do cultivo da cana-de-açúcar (citados anteriormente). O desempenho do modelo foi avaliado com base nos seguintes parâmetros estatísticos: Raiz do Erro Quadrático Médio (RMSE) e Erro Absoluto Médio (MAE). A partir dos resultados obtidos nos parâmetros estatísticos, os dados estimados pelo modelo HYDRUS-2D obtiveram uma boa concordância em relação aos dados observados do conteúdo de água e da concentração de potássio presente no perfil de solo. Diante disso, pôde-se concluir que o modelo HYDRUS-2D forneceu uma caracterização aceitável do volume de solo molhado nas diferentes fases de desenvolvimento da cana-de-açúcar e também sem a presença da cultura. / Drip irrigation systems are increasingly being used for such major crops as sugarcane to minimize water losses during irrigation. Saving water is becoming more and more important also in Brazil because of increasing water scarcity in the country. Proper design of a drip irrigation system is fundamental to implementation of optimal water and nutrient management practices, including possible application of fertilizers with the irrigation water (fertigation). This in turn requires reliable information about expected water and solute distributions in the soil profile around the emitters (drippers) during and after irrigation The main objective of this research was to use the HYDRUS-2D software package to estimate wetted soil volumes around the drippers during subsurface drip irrigation at different stages of sugarcane development (tillering, stalk growth, maturation), and to compare numerical results with experimental data. Field data collected for this purpose included soil moisture and potassium concentration distributions using Time Domain Reflectometry (TDR). Results made it possible to follow evolving solute concentration distributions around the drippers in real time, and to evaluate the performance of HYDRUS-2D. The research was divided into two steps: Step 1 involved collection of physical and hydraulic data of the soil, as well as of water and potassium distributions by means of a completely randomized experimental arrangement using two treatments, each with three replicates. Treatments 1 and 2 were for the scenarios without and with sugarcane cultivation, with both treatments having a flow emitter rate of 4.0 L h-1. Step 2 involved HYDRUS-2D simulations of the moisture and potassium concentration distributions around the drippers at different stages of sugarcane development. Model performance was evaluated using the following statistical parameters: Mean Squared Error Root (RMSE) and Mean Absolute Error (MAE). From the results obtained in the statistical parameters, HYDRUS-2D predictions obtained a good agreement with the observed data of water content and the potassium concentration in the soil profile. Therefore, it was concluded that HYDRUS-2D model provided an acceptable characterization of the wetted volume at different stages of development of sugarcane and also without the presence of culture.

Submitted by Fabio Sobreira Campos da Costa (fabio.sobreira@ufpe.br) on 2016-07-15T12:09:44Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Tese_Tassia Melo_Final.pdf: 21742689 bytes, checksum: d3eb5a7ea85beafabdb3f870e3431701 (MD5) / Made available in DSpace on 2016-07-15T12:09:44Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Tese_Tassia Melo_Final.pdf: 21742689 bytes, checksum: d3eb5a7ea85beafabdb3f870e3431701 (MD5) Previous issue date: 2015-12-18 / FACEPE / Técnicas compensatórias são implantadas com a finalidade de resgatar os mecanismos naturais de escoamento, diminuir as vazões a jusante e maximizar o controle de escoamento na fonte. A fim de contribuir com os estudos sobre essas técnicas, este trabalho apresenta um estudo experimental de uma trincheira de infiltração instalada na cidade de Recife / PE nos primeiros meses de vida útil. Foram avaliadas as funções de armazenamento de água no interior do sistema e a função de infiltração, através de modelagens analítica e numérica sobre o processo de recessão. O modelo de Bouwer (1969) foi adotado para a modelagem analítica de dez curvas de recessão com dados reais. Os parâmetros de resistências hidráulicas da base e das paredes apresentaram valores elevados, representando a formação de uma camada de colmatação na interface trincheira de infiltração - solo natural. O Hydrus 2D foi utilizado para modelar numericamente doze curvas de recessões com dados artificiais, a fim de parametrizar o comportamento de trincheiras de infiltração quando implantadas em solos de diferentes classificações texturais. A modelagem mostrou melhor desempenho hidráulico da trincheira de infiltração instalada em solos de composição arenosa. Por fim, para as curvas de recessão artificiais, foi avaliada a relação entre os parâmetros obtidos analiticamente - resistências hidráulicas, e numericamente - curva de retenção e condutividade hidráulica, e os resultados mostraram que não é possível relacionar os parâmetros obtidos analiticamente com os parâmetros clássicos hidrodinâmicos obtidos numericamente. / Compensatory techniques are implemented for the purpose of recovering the natural mechanisms flow, decrease the downstream flow and maximize the flow control at the source. In order to contribute to the studies on these techniques, this paper presents an experimental study of an installed infiltration trench in Recife / PE in the first months of life. They evaluated the water storage functions within the system and infiltration function, by analytical and numerical modeling of the recession process. The model Bouwer (1969) was adopted for the analytical modeling ten recession curves with real data. The parameters of hydraulic resistances of the base and the walls showed high values, representing the formation of a fouling layer infiltration trench interface - natural soil. 2D Hydrus numerically modeling was used to twelve curves recessions with artificial data, in order to parameterize the behavior of infiltration trenches when implemented in different soil conditions ratings. The modeling showed better hydraulic performance of the installed infiltration trench in sandy soil composition. Finally, for the artificial recession curves, it evaluated the relationship between parameters obtained analytically - hydraulic resistances, and numerically - retention curve and hydraulic conductivity, and the results showed that it is not possible to relate the parameters obtained analytically with the classic parameters hydrodynamic obtained numerically.

Dans un contexte de changement climatique dont les projections régionales sont incertaines, de forte variabilité inter-annuelle du cycle hydrologique, de forte croissance démographique et de changement d'occupation des sols, les questions relatives au cycle hydrologique et à la ressource en eau actuels et à venir sont cruciales. Dans un tel contexte, ce travail de thèse approfondit la connaissance du fonctionnement hydrologique du bassin versant de l'Ouémé supérieur (situé en climat soudanien au Bénin), en considérant l'ensemble des termes et des processus du cycle hydrologique.Dans un premier temps, le fonctionnement hydrologique de l'Ouémé supérieur est analysé à l'échelle d'un versant grâce au modèle Hydrus 2D. Cette analyse de processus s'appuie sur un ensemble complet de mesures (précipitations, évapotranspiration, humidité du sol, niveau piézométrique, débit en rivière) obtenues dans le cadre de l'observatoire hydrométéorologique AMMA-CATCH. Les simulations montrent que la forêt ripisylve vidange la nappe profonde et la déconnecte ainsi du réseau hydrographique. L'apport d'eau de la nappe profonde permet une transpiration de la forêt ripisylve toute l'année, y compris en saison sèche. Les écoulements en rivière ne sont pas produits uniquement par exfiltration d'écoulements latéraux de subsurface non saturés, les bas-fonds jouent probablement un rôle.À méso-échelle, nous cherchons à quantifier l'impact de la variabilité spatiale de la conductivité hydraulique à saturation sur le bilan hydrologique et l'évapotranspiration. Le modèle numérique utilisé est nTopAMMA, formalisme dérivé de TopMODEL. À partir de mesures de terrain, nous avons mis en évidence que la variabilité spatiale de la conductivité hydraulique à saturation est corrélée à l'occupation du sol du bassin d'étude. La prise en compte de cette variabilité spatiale dans le modèle nTopAMMA montre que l'état hydrique et l'évapotranspiration simulés localement par le modèle dépendent aux trois-quarts de la topographie et pour un quart de la conductivité hydraulique à saturation.Adoptant une approche ascendante, nous confrontons la représentation élaborée à l'échelle du versant à la modélisation hydrologique à méso-échelle. Nous analysons les processus et flux verticaux du modèle nTopAMMA. L'amélioration de la modélisation du cycle hydrologique de l'Ouémé supérieur par le modèle nTopAMMA nécessite (i) la prise en compte des hétérogénéités du bassin versant, (ii) la modification du formalisme de l'évapotranspiration, (iii) la diversification des sources de prélèvements évapotranspiratoires et (iv) l'intégration de la nappe d'altérites. / Understanding how the hydrological cycle and water resources availability evolve in the current context of global change (which encompass climate, environmental and population changes) is a critical issue, particularly in West Africa, where at regional scale, strong interannual and seasonal variabilities overlap with highly uncertain climate predictions. Within this framework, this work aims at improving our knowledge of the behavior of the Upper Oueme catchment in Benin (Sudanian climate), with an analysis of all the hydrological processes and terms of the terrestrial hydrological cycle.First, the hillslope scale is considered by using the Hydrus 2D software and field observations from the hydrometeorological observing system AMMA-CATCH: rainfall, actual evapotranspiration, soil moisture, groundwater level and river runoff. The principal result of this analysis is that the riparian forest transpiration depletes the deep groundwater and disconnects it from the river network. Water supply by the deep groundwater enables the riparian forest transpiration all year long and particularly during the dry season. Seepage of unsaturated subsurface lateral flows contributes to river runoff, but the "bas-fonds" seem to be other important contributors.Then, at mesoscale, we quantify the impact of the spatial variability of hydraulic conductivity on the simulated water balance, with focus on the evapotranspiration term. The numerical model nTopAMMA, especially derived from the TopMODEL hydrological model for the Upper Oueme catchment, is used here. Measurements from a specific field mission evidence the correlation between the hydraulic conductivity spatial variability and the land use one. By taking into account this variability, the simulation results show that evapotranspiration and water storage simulated on the Upper Oueme catchment at local (pixel) scale depend essentially on the topography (75 %) and to a lesser extent on the hydraulic conductivity (25 %).Finally, a bottom-up approach is adopted to analyse the hydrological modelling results at mesoscale, taking advantage of the modelling results at the hillslope scale. Vertical processes and fluxes simulated by nTopAMMA are analyzed. It is shown that an improvement of the Upper Oueme hydrological cycle modelling, with nTopAMMA, requires: (i) the consideration of the catchment heterogeneities, (ii) the modification of the evapotranspiration module, (iii) the diversification of the evapotranspiration sources and (iv) the integration of the deep groundwater reservoir.

La maîtrise du transfert de nitrates sous les systèmes irrigués est un objectif primordial dans l’agriculture moderne. Celle-ci exige la recherche, surtout en plein champ, de conduire une stratégie optimale de fertigation. Dans ce but, un protocole expérimental sur une parcelle de 2 ha a été mis en oeuvre pour analyser le devenir de l’’azote sous différents scénarios d’irrigation et de fertilisation d’une culture de maïs. Dans l’articulation de ce travail, et pour pouvoir étudier la dynamique de l’azote en systèmes irrigués, nous avons tout d’abord réussi à définir et clarifier la relation ambigüe entre la méthode d’irrigation (irrigation gravitaire, par aspersion ASP, en goutte à goutte de surface GGS ou enterré GGE) et les différentes transformations de l’azote (Fixation, Minéralisation, Immobilisation, Nitrification, Dénitrification et Volatilisation). Cette relation, peu claire et non traitée dans d’autres études similaires, a été étudiée en mettant l’accent sur l’effet de certains facteurs, comme par exemple, l’humidité de sol et sa température, sur l’activité microbienne et donc sur les différentes transformations de l’azote (comme la minéralisation) et ce en mettant en avant la relation directe ou indirecte avec les méthodes d’irrigation. Une différence significative a été observée pour la minéralisation in situ entre les traitements sans aucun apport d’engrais menés sous les deux méthodes d’irrigation GGE et ASP. Une méthode manuelle d’analyse a été ensuite mise au point et validée pour déterminer la concentration en azote dans les échantillons de sol prélevés dans le cadre de ce travail. Cette méthode peu onéreuse pourrait être profitable aux agriculteurs. Les données issues de l’ensemble des traitements ont été utilisées pour modéliser les flux hydriques et azotés à l’aide de modèle HYDRUS-2D pour les systèmes par aspersion et en goutte à goutte enterré. L’analyse de sensibilité aux paramètres liés au transfert de nitrates du modèle de transfert a permis d’estimer la dynamique azotée pour d’autres contextes hydro-pédo-climatiques plus complexes. En conclusion, la présente thèse a permis d’améliorer la connaissance du fonctionnement de la fertigation en irrigation goutte à goutte enterré par comparaison avec l’aspersion, en milieu méditerranéen, en vue d’une diminution des entrants agrochimiques dans un contexte d’économie de la ressource en eau. / The main goal in modern agriculture is the control of nitrogen fluxes in agricultural soils under the irrigation techniques. This objective requires a lot of research, especially in the field, to escort an optimal strategy of fertigation. For this purpose, an experimental protocol has been applied to follow the soil nitrogen fate for various irrigation and fertilization scenarios, during two intensive field campaigns in maize plots. In the articulation of our work, and to be able to examine the nitrogen dynamics in unsaturated agricultural soils under irrigated systems, we succeeded firstly to determine and clarify the ambiguous relation between the irrigation techniques (flood irrigation, sprinkler irrigation, surface and subsurface drip irrigation) and the different nitrogen transformations (Fixation, Mineralization, Immobilization, Nitrification, Denitrification and Volatilization) in agricultural contexts. This relationship, which is unclear and untreated in other similar studies, has been reviewed by studying the impact of certain factors, such as soil moisture and soil temperature under different irrigation techniques, on microbial soil activity and therefore on the nitrogen transformations (such as mineralization). A significant difference of mineralization was observed in maize plots with no fertilizer application treatment between sprinkler irrigation and subsurface drip irrigation. The experimental data collected have been used to analyze the water and nitrogen fluxes for various initial conditions and fertilisation strategies under sprinkler and subsurface drip irrigation by using the HYDRUS-2D model. Analyzing the sensitivity of nitrogen fluxes parameters using HYDRUS-2D allowed to estimate the nitrogen dynamics under more complex agro-pedoclimatic contexts. In conclusion, the present study allowed to improve the fertilization knowledge under both the sprinkler and subsurface drip irrigation in a Mediterranean environment.

Advancements in computation and development of physically based hydrologic models to simulate complex vadose zone scenarios helped the research community to evaluate different scenarios easily compared to long-term field experiments. However, some field data collection is necessary to obtain input data such as soil properties, water usage and land management practices to validate the model performance specific to the site. Data obtained from field experiments conducted in 2011 at Hespler farms, Winkler, MB was used in this research for model calibration and validation. The hydrologic model, HYDRUS (2D/3D) was evaluated using parameters such as visual and statistical analysis. Model evaluation during the calibration and validation stage gave RMSE values of 0.019 and 0.015 cm3 cm-3; PBIAS values of -1.01 and -0.14, respectively, suggesting that the model was efficient in simulating soil water content similar to the field observed data. The validated models were then used to simulate outcomes for different scenarios such as 30-year rainfall data (1986 – 2015), different soil physical properties, and drainage system design parameters. Models simulating free drainage predicted lower soil water content compared to controlled drainage leading to 6 – 60 more trafficable days for 8 m spacing and 0.9 drain base depth. Free drainage predicted 8 – 110 additional trafficable days compared to controlled drainage for 15 m spacing and 1.1 drain depth. Heavier than normal rainfall events caused high water contents leading to a few years with a very low to no trafficable days under controlled drainage conditions. The comparisons are presented based on models using free drain conditions. Models with 8-m drain spacing predicted a 1 to 10-day increase in the number of trafficable days compared to the 15-m drain spacing. Drains placed at a base depth of 1.1 m below the soil surface predicted 4 - 40 more trafficable days compared to those installed at a base depth of 0.9 m. / October 2017

A major design issue in the implementation of a Subsurface Drip Irrigation (SDI) system for extensively crops such as alfalfa (i.e. crops that cover the entire surface as opposed to row crops), is the determination of the appropriate depth of placement of the drip line tubing. It is important to allow necessary farming operations with heavy equipment at harvesting times while still providing adequate water to meet the crop water requirements. It is also a need to ensure appropriate spacing between the dripline laterals to assure reasonable lateral irrigation uniformity for plant germination. In this study, the program HYDRUS-2D was used to determine the wetting pattern above and laterally from a subsurface drip emitter of an SDI system, for three soils typically found in Southern California and Arizona, a Sandy Clay Loam (SCL), a Clay Loam (CL) and a Loam (L). The design and management conditions from an experimental alfalfa field with an SDI system located at Holtville CA were used and analyzed. The first irrigation design was with a drip line depth of placement of 30 cm and the second design with an installation depth of 50 cm. The two different irrigation management schemes utilized by the farmers and producers in that area were: one with a running time of six hours and a frequency of every three days and the second one with an irrigation running time of twenty-four hours with a frequency of seven days or irrigation every week. After having carried out the analysis and studies of the irrigation designs and management schemes mentioned above, a new model with its corresponding management was proposed to meet the alfalfa water requirements under that particular field and weather conditions while we ensure a sufficiently dry soil surface at harvesting time for each soil case. This irrigation management includes twelve hours or irrigation every three days, for each of the three soils analyzed. It was found that the vertical rise of water above the emitters on the day of the cut, for our recommended SDI management was 26 cm, 29 cm, and 27 cm, with a moisture content at the soil surface of 14.9%, 24%, and 13% for the SCL, CL, and L soils respectively. Then, through the utilization of classical soil mechanics theory, an analysis to calculate the increase in stress on soils at any depth due to a load on the surface from a conventional tractor used during harvest operations was made for the proposed SDI system. The results from the increase in stress were then used together with soil strength properties such as shear strength as a function of soil moisture content to determine the minimum allowable depth of placement of the drip line tubing to ensure that soil failure does not occur. The load increase from a 3,300-kg four-wheel tractor was found to be 0.59 kg/cm2 under a rear tire at 10 cm below the surface and 0.07 kg/cm2 at 70 cm below the surface. To ensure that shearing failure does not occur, a stress analysis using Mohr’s circle indicated that the soil moisture content at 10 cm below the surface should be no greater than 26.8%, 32.7%, and 27% in the SCL, CL, and L soils respectively. The mimimum moisture content of 26.8% occur at 10 cm above the drip line for a SCL soil, which means that the minimum depth placement to avoid failure would be 40 cm below the surface. A similar analysis for the CL and L yielded minimum installation depths of 35 cm and 40 cm respectively. This type of analysis is useful in determining the depth of placement of SDI drip line tubing to ensure adequate trafficability of soil irrigated with subsurface drip irrigation systems. An additional outcome of the modeling study was the determination of the lateral extent of the wetted zone which can be used to determine the appropriate lateral spacing between drip line tubing. Thus, to ensure adequate spatial coverage by a subsurface drip system, the maximum horizontal spacing should be of 80 cm for SCL and L soils and 90 cm in CL soils.

Made available in DSpace on 2016-06-02T20:00:55Z (GMT). No. of bitstreams: 1 5728.pdf: 4886967 bytes, checksum: 9a66021bc6eec94037ca58204cb8fb84 (MD5) Previous issue date: 2013-08-23 / Financiadora de Estudos e Projetos / Stormwater flooding in urban centers today is the direct result of ground impermeabilization and the ineffective dimensioning of stormwater drainage systems. In order to control these events, innovative low impact stormwater drainage facilities are used in Brazil, which are efficient in controlling sharp peak flows in urban watersheds without, however, affecting the aesthetic appearance of the landscape in these environments. The purpose of this study is to model and estimate the volume of water infiltrated into the soil where a compensatory stormwater drainage system is inserted, which can contribute to groundwater recharge. Modeling was performed by means of a physical storage method and storage variation in soil using a tensiometer, and in digital form using the Hydrus 2D/3D software package. The monitored drainage system and the digitally designed system consist of a water retention basin, a ditch or filter, and an infiltration trench. Groundwater recharge was estimated based on soil analyses, geophysical investigations, flow measurements, and rainfall data, in addition to data collected during 454 days of continuous monitoring of the system by means of tensiometers installed on-site, rain gauges, and the construction of bimodal soil water retention curves using the filter paper method. The moisture content at different depths, the zero water flow plane, and the volumes moving in the soil matrix were calculated based on the identification of the soil water content and matric potential, the hydraulic conductivity in saturated conditions at the monitored depths, and the soil s characteristic curves. The results of the Soil Water Retention Curves (SWRC) and soil moisture content were negligible starting from a depth of 80cm. However, the groundwater recharge rate estimated by the tensiometer method and by the Hydrus digital model was about 45% of the total volume of rainfall. / Atualmente, eventuais problemas de enchentes e inundações, são causas diretas da impermeabilização de áreas nos centros urbanos e do ineficaz dimensionamento da drenagem pluvial nas cidades. No intuito de se controlar estes eventos, equipamentos de drenagem de baixo impacto são inovadoras no Brasil e eficientes no controle de vazões de pico acentuadas em bacias urbanas, sem sobretudo, renunciar à estética e à paisagem nestes ambientes. Neste trabalho objetivou-se modelar e estimar o volume de água infiltrado no solo, onde um sistema de drenagem pluvial compensatória está inserido, que é capaz de contribuir com a recarga freática. A modelagem foi realizada por meio do método de armazenamento e variação da armazenagem no solo com utilização de tensiômetro e de forma digital utilizando-se do software Hydrus 2D/3D. O sistema de drenagem monitorado e o diagramado digitalmente são constituídos de uma bacia de retenção de água, uma vala ou filtro gramado e uma trincheira de infiltração. Na tentativa de estimar a recarga freática realizaram-se, conjuntamente, análises de solo, investigações geofísicas, medidas de vazão, coleta de dados de chuva, além do monitoramento contínuo em 454 dias do sistema através da instalação de tensiômetros no local, pluviógrafos, além da construção de curvas bimodais de retenção de água nos solos por meio do método do papel filtro. A partir da identificação dos potenciais mátricos do solo, da condutividade hidráulica em condições saturadas para as profundidades monitoradas e da obtenção das curvas características do solo, foi possível calcular o teor de umidade em diferentes profundidades, identificar o plano de fluxo zero e calcular os volumes em movimento na matriz do solo. Os resultados obtidos pela verificação das Curvas de Retenção de Água no Solo (CRAs) e umidades de campo foram pouco expressivos a partir de 80cm de profundidade, entretanto, a recarga estimada obtida pelo método dos tensiômetros e pelo modelo digital Hydrus ficou em torno de um valor médio de 45% do volume total precipitado.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The environmental contamination by metallic trace elements is a problem that is getting worse around the world due to the growth and the technologic development of the humanity. Among the main sources of this kind of contamination are the atmospheric deposition of particles in soils located around industrial complexes and the prolonged and concentrated application of organic wastes in the soil. When present at the soil surface, these elements will migrate in depth and may reach the subsurface water bodies, causing their contamination. This study aimed to use the software Hydrus-2D to simulate the vertical redistribution of zinc, lead and copper in soil profiles contaminated by air pollution or by the application of swine liquid manure as well the transfer of these metallic trace elements into the groundwater. Chemical models were used under different hypotheses of reactivity of these elements with the soil particles and the physical, hidric and chemical characteristics of each soil profile. In the attempt to validate these models, it was simulated the vertical transports of zinc and lead, between 1900 and 2000, at three uses of a soil in northern France and of zinc and copper, between 2000 and 2008, at a soil profile located in Santa Maria RS, Brazil. Using a two sites chemical model with the kinetic constant decreased to 1% of the value measured in the laboratory, the simulations of the vertical transport of the metallic trace elements were validated in all soil profiles. This model was able to redistribute efficiently these elements in the profile, according their concentrations determined in situ. It was also predicted that the transfer of these contaminants do not represent, until now, any risk of pollution of the groundwater. Even with the continued application of high doses of swine liquid manure until 2058, the predicted increasing of zinc and copper concentrations in soil solution will not represent a risk of subsurface waters pollution. However, the model estimated that copper will be accumulated on the surface of this profile in greater quantities than zinc, increasing its concentration to levels above the value of intervention to agricultural areas. It was concluded that Hydrus-2D was a useful tool in detecting and/or forecasting environmental problems arising from the accumulation of metallic trace elements in soil and its leaching to the subsurface water bodies. / A contaminação do ambiente por elementos traços metálicos é um problema que vem se agravando em todo o mundo. Ela é decorrente do crescimento e do desenvolvimento tecnológico da humanidade, que apresenta, entre as principais fontes, as contaminações oriundas da deposição atmosférica de partículas aos solos localizados no entorno de complexos industriais e da aplicação concentrada e prolongada de resíduos orgânicos. Uma vez presentes na superfície do solo, esses elementos migrarão em profundidade, podendo atingir os corpos de água subsuperficiais e contaminá-los. Este trabalho teve por objetivo principal usar o programa computacional Hydrus-2D para simular a redistribuição vertical de zinco, chumbo e cobre no perfil de solos contaminados por poluição atmosférica ou pela aplicação de dejeto líquido de suínos e a transferência desses elementos traços metálicos rumo ao lençol freático. Para tal, foram usados modelos químicos sob diferentes premissas de reatividade dos elementos com as partículas do solo e as características físico-hídricas e químicas de cada perfil de solo. Buscou-se validar estes modelos, simulando os transportes verticais de zinco e chumbo, entre 1900 e 2000, em três usos de um solo do norte da França e de zinco e cobre, entre 2000 e 2008, num perfil de solo localizado em Santa Maria RS, Brasil. Utilizando um modelo químico de dois sítios com a constante cinética diminuída a 1% do valor medido em laboratório, as simulações do transporte vertical dos elementos traços metálicos foram validadas em todos os perfis de solo. Esse modelo foi capaz de redistribuir eficientemente estes elementos no perfil, conforme suas concentrações determinadas in situ. Ele também previu que a transferência destes contaminantes não representou, até o momento, nenhum risco de poluição da água do lençol freático. Mesmo com a manutenção da aplicação de altas doses de dejeto líquido de suínos até 2058, o aumento na concentração de zinco e cobre na solução do solo previsto não representará risco à poluição das águas subsuperficiais. Porém, o modelo estimou que o cobre se acumulará na superfície deste perfil em maior quantidade que o zinco, elevando sua concentração para níveis acima do valor de intervenção para áreas agrícolas. Dessa forma, o Hydrus-2D apresentou-se como uma ferramenta muito útil na detecção e/ou previsão de problemas ambientais decorrentes do acúmulo de elementos traços metálicos no solo e da sua lixiviação para os corpos de água subsuperficiais.

This master's thesis deals with the modeling of biochemical processes in saturated vertical filter (which is often part of constructed treatment wetland) using software HYDRUS 2D and the module Constructed Wetland CW2D. The introductory part of this thesis is the literature research of expertise that are introduce with the theme constructed treatment wetlands and should also provide a basic overview of the mathematical or numerical modeling issue. The last chapter describes the theoretical introduction of software HYDRUS 2D and CW2D module, it is the practical part used to create a numerical l model. The practical part is based on theoretical knowledge and demonstrates the creating process of mathematical model in program HYDRUS 2D, simulating the real biochemical processes on the vertical saturated filter. The model is created in the program HYDRUS 2D CW2D and based on real operated constructed wetland. The thesis describes the calibration and followed verification of this model. The final model can well simulate the real filter behavior and allows user to get information about the output concentrations of waste water emission, such as ammonia nitrogen (N-NH4+) and chemical oxygen demand (COD). The results should in the future contribute to create software intended to draft and layout constructed wetlands.