New Zealand's greenhouse gas inventory is dominated by the agricultural trace gases, CH4 and N2O instead of CO2, which is dominant on a global scale. While the majority of the anthropogenic CH4 is emitted by ruminant animals as a by-product of enteric fermentation, N2O is mainly produced by microbial processes occurring in the soil. In grazed pastoral soils, N2O is generated from N originating from dung, urine, effluent applied to land, biologically fixed N2 and fertiliser. The amount of emission depends on complex interactions between soil properties, climatic factors and management practices. Increased intensification of pastoral agriculture in New Zealand, particularly in dairying has led to an increased production of farm dairy effluent. Traditionally, direct disposal of nutrient rich farm dairy effluents (FDE) into water bodies was an acceptable practice in New Zealand, but with the introduction of the Resource Management Act (1991), discharge of effluents into surface waters is now a controlled activity and many Regional Councils encourage the land irrigation of effluents to protect surface water quality. While the impact of grazing and FDE irrigation on groundwater contamination through leaching and runoff of nutrients has been studied extensively, there has been only limited work done on the effect of these practices on air quality as affected by N2O emission. This thesis examines the effects of various factors, such as compaction due to cattle treading, and the nature, application rate and time of effluent application on N2O emission in relation to the changes in the soil physical properties and C and N transformation from a number of small plot and field experiments. The results were then used, together with data from the literature, to predict the emissions from effluent irrigated pastures using a process-based model. In grazed pastures, animal treading causes soil compaction, which results in decreased soil porosity and increased water filled pore space that stimulate the denitrification rate as well as influence the relative output of N2O and dinitrogen (N2) gases. A field plot study was conducted to determine N2O emission from different N sources as affected by soil compaction. The experiment comprised two main treatments (uncompacted and compacted) to which four N sources (natural cattle urine, potassium nitrate, ammonium sulphate and urea at the rate of 600kg N ha-1) and a control (water only) were applied. Compaction was obtained through driving close parallel tracks by the wheels of the vehicle. The changes in the soils physical properties (bulk density, penetration resistance (PR), soil matric potential and oxygen diffusion rate (ODR) due to the compaction created by the wheel traction of the vehicle were compared with the changes in these properties due to the treading effect of grazing cattle, which was monitored in another field experiment. The N2O fluxes were measured using a closed chamber technique. The compaction at the grazing trial and at the wheel traction experimental plot caused significant changes in soil bulk density, PR, soil matric potential and ODR values. Overall, the bulk density of the compacted soil was higher than the uncompacted soil by 6.7% (end of 3 weeks) and 4.9% (end of 1 week) for the field experiment and the grazing trial, respectively. Results suggest that maximum compaction occurred in the top 0-2 cm layer. Compaction caused an increase in N2O emission, which was more pronounced in the nitrate treatment than in the other N sources. In the case of the compacted soil, 10% of the total N applied in the form of nitrate was emitted, whereas from uncompacted soil this loss was only 0.7%. N2O loss was found to decrease progressively from the time of application of N treatments. Total N2O emission for the three month experimental period ranged from 2.6 to 61.7 kg N2O-N ha-1 for compacted soil and 1.1 to 4.4 kg N2O-N ha-1 for uncompacted soil. In the second field plot experiment, the results of N2O fluxes from treated farm dairy effluent (TFDE), untreated farm dairy effluent (UFDE), treated piggery farm effluent (TPFE) and treated meat effluent (TME) applied to 2m x 1m plots for 'autumn' (February-April) and 'winter' (July-September) are described. Effluent irrigation resulted in higher emissions during both the seasons indicating that the supply of C and N through effluent irrigation contributed to increased N2O emission. The highest emissions were observed from TPFE (2.2% of the applied N) and TME (0.6% of the applied N) during the autumn and winter seasons, respectively. Emissions generated by the TFDE application were the lowest of the four effluent sources but higher than the water and control treatments. The effect of effluent irrigation on N2O emission was higher during the autumn season than the winter season. The effect of key soil and effluent factors such as water filled pore space (WFPS), nitrate, ammonium and available C in soil and effluents on N2O emission was examined using regression equations. The third field plot experiment examined the effect of four TFDE application rates (25mm, 50mm, 75mm and 100mm) on N2O emission. Treatments were added to 2m x 1m plots lined with plastic sheet to restrict the flow of effluent. The N2O emission increased with the increasing effluent loading rate, with the emission ranging from 0.8 to 1.2% of the added N. This can be attributed to the increasing addition of N and C in the soil with the increasing application rate of the effluent. Besides, providing C and N substrates, the effluent application increased the WFPS of the soil, thereby creating conditions conducive for dentrification and N2O emission. A field experiment was conducted at the Massey University No 4 Dairy farm in which N2O emission and related soil and environmental parameters were monitored for two weeks following the TFDE applications over an area of 0.16 ha in September 2003 (21mm), January 2004 (23mm) and February 2004 (16mm). Emissions were measured by a closed chamber technique with 20 chambers for each treatment, in order to cover the variability present in the field. N2O emissions increased immediately after the application of the effluent, and subsequently dropped after about two weeks. The total N2O emitted from the effluent application after the first, second and third irrigation was 2%, 4.9% and 2.5%, respectively of the total N added through the effluent. The higher emission observed during the second effluent irrigation event was due to high soil moisture content during the measurement period. Moreover effluent was applied immediately after a grazing event leading to more N and C input into the soil through excretal deposition. In this experiment the residual effect of effluent application on N2O emission was also examined by monitoring emissions 12 weeks after the effluent application. The emissions from the control and effluent irrigated plots were similar, indicating that there was no residual effect of the effluent irrigation on N2O emissions. In a separate field study, N2O emission was monitored at the Massey University No 4 Dairy farm to examine the effect of a grazing event of moderate intensity on N2O emission. The treatments consisted of a grazed and an ungrazed control. The fluxes from the grazed site were much higher than for the ungrazed site with the total emissions from the former site being 8 times higher than the latter site for the entire experimental period. A modified New Zealand version of denitrification decomposition model (DNDC), a process based model, namely "NZ-DNDC", was used to simulate N2O emission from the TFDE application in the field experiment. The model was able to simulate the emission as well as the WFPS within the range measured in the field. But simulated emissions from the TFDE were slightly lower than measured values. Improvements in the parameterisation for effluent irrigation are likely to further improve the N2O simulations.

Lakes resulting from open pit mining may be potential water resources or potential environmental problems, depending on their water quality. As the global abundance of pit mines and pit lakes increases, there is increasing pressure on the mining industry to create pit lakes that have environmental, social, and/or economical utility. This thesis uses an interdisciplinary approach involving mineralogy, physical limnology, and geochemistry to predict and improve the water quality of a proposed pit lake at the Martha gold mine, New Zealand. A mineral quantification method developed for this study measured the distributions and concentrations of wall rock minerals, and identified 8 relatively homogeneous wall rock regions, called mineral associations. Acid-base accounting using calcite and pyrite quantities identified 3 associations with acid-generating potential. Three physical limnology tools (relative depth, wedderburn number, and numerical modeling with DYRESM), predicted that the upper 2/3 of the lake will circulate annually during the winter turnover period, whereas the lower 1/3 will remain permanently isolated. Permanent stratification resulted from density differences between groundwater and river water inputs during lake filling, plus lake morphology. The geochemical model used the distribution of mineral associations to characterize the composition of pit wall runoff, and used the limnologic prediction to define the mixing frequency, mixing depth, and layer volumes. Initial modeling with the geochemical program PHREEQC indicated the lake will have a pH of 5, and Cu and Zn concentrations that exceed aquatic life protection guidelines. Sensitivity analyses showed that subaqueous water-rock reactions did not have a significant affect on lake pH, suggesting these reactions are less important geochemical factors in pyrite-bearing pit lakes. Surface adsorption onto ferrihydrite reduced concentrations of As, Pb, and Cu, suggesting these reactions are important geochemical factors in pit lakes. By covering the acid-generating mineral associations, lake pH increased above 6.5, allowing for future recreational use. Concentrations of Cu complied with aquatic life protection guidelines, however, Zn concentrations remained above these guidelines. This study demonstrates the value of interdisciplinary pit lake predictions in the design of closure plans for open pit mines. Such studies improve the ability of mining companies to sustainably develop mineral resources.

Lakes resulting from open pit mining may be potential water resources or potential environmental problems, depending on their water quality. As the global abundance of pit mines and pit lakes increases, there is increasing pressure on the mining industry to create pit lakes that have environmental, social, and/or economical utility. This thesis uses an interdisciplinary approach involving mineralogy, physical limnology, and geochemistry to predict and improve the water quality of a proposed pit lake at the Martha gold mine, New Zealand. A mineral quantification method developed for this study measured the distributions and concentrations of wall rock minerals, and identified 8 relatively homogeneous wall rock regions, called mineral associations. Acid-base accounting using calcite and pyrite quantities identified 3 associations with acid-generating potential. Three physical limnology tools (relative depth, wedderburn number, and numerical modeling with DYRESM), predicted that the upper 2/3 of the lake will circulate annually during the winter turnover period, whereas the lower 1/3 will remain permanently isolated. Permanent stratification resulted from density differences between groundwater and river water inputs during lake filling, plus lake morphology. The geochemical model used the distribution of mineral associations to characterize the composition of pit wall runoff, and used the limnologic prediction to define the mixing frequency, mixing depth, and layer volumes. Initial modeling with the geochemical program PHREEQC indicated the lake will have a pH of 5, and Cu and Zn concentrations that exceed aquatic life protection guidelines. Sensitivity analyses showed that subaqueous water-rock reactions did not have a significant affect on lake pH, suggesting these reactions are less important geochemical factors in pyrite-bearing pit lakes. Surface adsorption onto ferrihydrite reduced concentrations of As, Pb, and Cu, suggesting these reactions are important geochemical factors in pit lakes. By covering the acid-generating mineral associations, lake pH increased above 6.5, allowing for future recreational use. Concentrations of Cu complied with aquatic life protection guidelines, however, Zn concentrations remained above these guidelines. This study demonstrates the value of interdisciplinary pit lake predictions in the design of closure plans for open pit mines. Such studies improve the ability of mining companies to sustainably develop mineral resources.

Oil palm is the largest national crop produced in Papua New Guinea. It is grown on over 80,000 ha of young volcanic soils in five Provinces, employs over 12,000 workers and uses >12,000 tonnes of fertiliser to offset nitrogen deficiency which is the most limiting factor to production. Oil palms strip out 160 - 200 kg N ha-1 yr-1 from the soil. Nitrogen fertilisers account for 60-70 % of all variable production costs but 40-60 % of applied fertiliser cannot be accounted for. Few studies have investigated the amounts of nitrogen lost via leaching, denitrification, volatilisation or as surface runoff in tropical soils and none have been done in Papua New Guinea. Oil palm soils typically have extremely high infiltrabilities (80-8,500 mm hr-1) and receive high annual rainfall which throughfall makes spatially non-uniform. The objective of this study was to assess and quantify nitrogen losses and suggest strategies that might assist in reducing them and their impact on the environment. The modest facilities available at the two research sites, West New Britain (Dami) and Oro (Sangara) Provinces, meant that no analytical work could be done on-site, so simple but appropriate methods were used to evaluate losses, with samples collected, preserved and sent off-shore for analysis. Large four-palm plots were used to evaluate runoff; a gas trap was used to collect evolved nitrous oxide, and lysimeters, suction cups and finally an in situ destructive soil sampling procedure were all used to assess leaching losses and the rate of nitrification of ammonium fertiliser. Results suggest that under the extreme total annual rainfall at Dami (3,500-4,000 mm) and to a lesser extent at Sangara (2,500-3,000 mm), leaching is the dominant loss pathway, with the rate of loss depending, to some extent, on the rate of nitrate formation and the retentivity of the soil for ammonium, but mainly on the rate at which drainage water is generated. A leaching model was developed that indicated that the average residence time of nitrogen fertiliser in the root zone (0-50 cm) varied from 21 days in February, at Dami, to 190 days in May, at Sangara.

Made available in DSpace on 2016-12-23T13:51:43Z (GMT). No. of bitstreams: 1 Dissertacao - Danilo Costa Fukunaga.pdf: 8515561 bytes, checksum: ba38cee72ad050285f5ea5c0e36c53d6 (MD5) Previous issue date: 2012-08-24 / O aumento da atividade econômica e do número de habitantes no mundo, juntamente com o uso não sustentável dos recursos hídricos, os despejos de efluentes sem tratamento no ambiente e o manejo inadequado das bacias hidrográficas, têm contribuído para diminuição da disponibilidade de água no planeta. Apesar de ser um recurso natural renovável, a água que retorna da atmosfera não ocorre de maneira uniformemente distribuída, nem no espaço geográfico, nem no tempo, tornando a sua boa gestão essencial para diminuição das consequências desastrosas dos eventos extremos de cheia e de escassez. Mas, uma gestão exitosa requer, além de profissionais qualificados, o uso de ferramentas para suporte à tomada de decisão. Neste contexto, a utilização de modelos hidrológicos pode auxiliar no planejamento e avaliação de práticas conservacionistas de solo e água e de manejo de bacias hidrográficas. Do exposto, o presente estudo teve o objetivo de avaliar a aplicabilidade do SWAT para a estimação de vazões em bacias hidrográficas no sul do Estado do Espírito Santo. Foram estudadas: a microbacia do córrego Jaqueira (MBJ), com aproximadamente 22,6 ha, e a sub-bacia do rio Itapemirim, à montante da estação fluviométrica de Rive (BIMR), com aproximadamente 2.237 km². Devido ao alto número de falhas e ao curto período de monitoramento hidrológico, não foi possível calibrar e verificar a aplicabilidade do modelo para a MBJ. Para a BIMR, na análise das vazões médias, estimou-se 45,5 m³ s-1 antes da calibração, e 32,6 m³ s-1 após a calibração, muito próxima da vazão média monitorada de 36,9 m³ s-1. Para o período de validação, a vazão média monitorada foi 22% maior (45,0 m³ s-1), enquanto a estimada foi de 33,9 m³ s-1, permanecendo próxima da vazão média estimada calibrada. Em análise gráfica, observou-se que, antes da calibração, as vazões mínimas estimadas ficaram abaixo das observadas, porém as vazões de pico eram superestimadas. Após a calibração, as vazões mínimas tiveram melhores correlações, enquanto as vazões de pico foram subestimadas. Na análise dos índices estatísticos, o R² passou de 0,74 para 0,76 após a calibração, mas foi reduzido para 0,63 no período de validação. Para o coeficiente de Nash Sufcliffe, houve uma melhora significativa do valor após a calibração, passando de -0,38 para 0,75, permanecendo com um valor aceitável de 0,57 no período de validação. O SWAT foi capaz de simular vazões em bacias hidrográficas do Sul do Espírito Santo, desde que não houvesse muitas falhas nos dados monitorados, sendo capaz inclusive de simular dados de outros períodos para os quais os parâmetros não foram ajustados / The increasing of world economic activity and the number of inhabitants, along with the unsustainable use of water resources, untreated wastewater release into the environment and inadequate watersheds management, has contributed to water availability decrease on the planet. Despite being a renewable natural resource, the water that returns from the atmosphere does not occur evenly distributed, either in geographic space or in time, making its good management essential to reduce disastrous consequences of extreme events of floods and droughts. But a successful management requires, as well as qualified professionals, the use of support decision tools. In this context, the use of hydrological models can assist in planning and assessment of conservation practices for soil and water and watershed management. In this light, the present study aimed to evaluate the SWAT capability to estimate flow in river basins in the southern of Espírito Santo state, Brazil. The Jaqueira stream watershed (MBJ), with approximately 22.6 ha, and Itapemirim river basin, upstream of the Rive fluviometric station (BIMR), with approximately 2,237 km², were studied. Due to the high number of gaps and short-term hydrological monitoring, was not possible to calibrate and verify model applicability for the MBJ. For BIMR, the analysis of the average flow rate was estimated by 45.5 m³ s-1, before calibration, and 32.6 m³ s-1 after calibration, closely to the monitored average flow, that was 36.9 m³ s-1. For the validation period, the average flow monitored was 22% higher (45.0 m³ s-1), while the estimated flow was 33.9 m³ s-1, remaining closely to the average calibrated estimated flow. In graphical analysis, it was observed that before calibration, the estimated minimum flow rates were below those observed, but the peak flows were overestimated. After calibration, the minimum flows had better correlations, while the peak flows were underestimated. In the analysis of statistical indexes, the R² increased from 0.74 to 0.76, after calibration, but was reduced to 0.63 in the validation period. For the Nash Sufcliffe coefficient, was verified a significant improvement of its value after calibration, from -0.38 to 0.75, remaining with an acceptable value in the validation period, 0.57. The SWAT was able to simulate flows in river basins in the southern of Espírito Santo state, since there were not many gaps in the monitored data, and also being able to simulate data from other periods for which the parameters were not adjusted

Made available in DSpace on 2016-12-23T13:51:54Z (GMT). No. of bitstreams: 1 Introducao_Revisao.pdf: 957704 bytes, checksum: e17ebeae5294a2c7986614add6f88f96 (MD5) Previous issue date: 2012-08-24 / O aumento da atividade econômica e do número de habitantes no mundo, juntamente com o uso não sustentável dos recursos hídricos, os despejos de efluentes sem tratamento no ambiente e o manejo inadequado das bacias hidrográficas, têm contribuído para diminuição da disponibilidade de água no planeta. Apesar de ser um recurso natural renovável, a água que retorna da atmosfera não ocorre de maneira uniformemente distribuída, nem no espaço geográfico, nem no tempo, tornando a sua boa gestão essencial para diminuição das consequências desastrosas dos eventos extremos de cheia e de escassez. Mas, uma gestão exitosa requer, além de profissionais qualificados, o uso de ferramentas para suporte à tomada de decisão. Neste contexto, a utilização de modelos hidrológicos pode auxiliar no planejamento e avaliação de práticas conservacionistas de solo e água e de manejo de bacias hidrográficas. Do exposto, o presente estudo teve o objetivo de avaliar a aplicabilidade do SWAT para a estimação de vazões em bacias hidrográficas no sul do Estado do Espírito Santo. Foram estudadas: a microbacia do córrego Jaqueira (MBJ), com aproximadamente 22,6 ha, e a sub-bacia do rio Itapemirim, à montante da estação fluviométrica de Rive (BIMR), com aproximadamente 2.237 km². Devido ao alto número de falhas e ao curto período de monitoramento hidrológico, não foi possível calibrar e verificar a aplicabilidade do modelo para a MBJ. Para a BIMR, na análise das vazões médias, estimou-se 45,5 m³ s-1 antes da calibração, e 32,6 m³ s-1 após a calibração, muito próxima da vazão média monitorada de 36,9 m³ s-1. Para o período de validação, a vazão média monitorada foi 22% maior (45,0 m³ s-1), enquanto a estimada foi de 33,9 m³ s-1, permanecendo próxima da vazão média estimada calibrada. Em análise gráfica, observou-se que, antes da calibração, as vazões mínimas estimadas ficaram abaixo das observadas, porém as vazões de pico eram superestimadas. Após a calibração, as vazões mínimas tiveram melhores correlações, enquanto as vazões de pico foram subestimadas. Na análise dos índices estatísticos, o R² passou de 0,74 para 0,76 após a calibração, mas foi reduzido para 0,63 no período de validação. Para o coeficiente de Nash Sufcliffe, houve uma melhora significativa do valor após a calibração, passando de -0,38 para 0,75, permanecendo com um valor aceitável de 0,57 no período de validação. O SWAT foi capaz de simular vazões em bacias hidrográficas do Sul do Espírito Santo, desde que não houvesse muitas falhas nos dados monitorados, sendo capaz inclusive de simular dados de outros períodos para os quais os parâmetros não foram ajustados / The increasing of world economic activity and the number of inhabitants, along with the unsustainable use of water resources, untreated wastewater release into the environment and inadequate watersheds management, has contributed to water availability decrease on the planet. Despite being a renewable natural resource, the water that returns from the atmosphere does not occur evenly distributed, either in geographic space or in time, making its good management essential to reduce disastrous consequences of extreme events of floods and droughts. But a successful management requires, as well as qualified professionals, the use of support decision tools. In this context, the use of hydrological models can assist in planning and assessment of conservation practices for soil and water and watershed management. In this light, the present study aimed to evaluate the SWAT capability to estimate flow in river basins in the southern of Espírito Santo state, Brazil. The Jaqueira stream watershed (MBJ), with approximately 22.6 ha, and Itapemirim river basin, upstream of the Rive fluviometric station (BIMR), with approximately 2,237 km², were studied. Due to the high number of gaps and short-term hydrological monitoring, was not possible to calibrate and verify model applicability for the MBJ. For BIMR, the analysis of the average flow rate was estimated by 45.5 m³ s-1, before calibration, and 32.6 m³ s-1 after calibration, closely to the monitored average flow, that was 36.9 m³ s-1. For the validation period, the average flow monitored was 22% higher (45.0 m³ s-1), while the estimated flow was 33.9 m³ s-1, remaining closely to the average calibrated estimated flow. In graphical analysis, it was observed that before calibration, the estimated minimum flow rates were below those observed, but the peak flows were overestimated. After calibration, the minimum flows had better correlations, while the peak flows were underestimated. In the analysis of statistical indexes, the R² increased from 0.74 to 0.76, after calibration, but was reduced to 0.63 in the validation period. For the Nash Sufcliffe coefficient, was verified a significant improvement of its value after calibration, from -0.38 to 0.75, remaining with an acceptable value in the validation period, 0.57. The SWAT was able to simulate flows in river basins in the southern of Espírito Santo state, since there were not many gaps in the monitored data, and also being able to simulate data from other periods for which the parameters were not adjusted

As estradas rurais não pavimentadas são importantes geradoras de crescimento em países subdesenvolvidos, desempenhando papel essencial na produção e comercialização de produtos primários e no acesso a bens e serviços. Cerca de 78,6% do sistema de transporte brasileiro é composto por estradas não pavimentadas, sem contabilizar as estradas de uso privado de propriedades rurais. No âmbito florestal as estradas não pavimentadas tem sido o principal foco de estudos relacionados à erosão, pois são os agentes que mais contribuem para o escoamento superficial e geração de sedimentos. A aceleração dos processos erosivos proporcionada pelas estradas está vinculada às mudanças dos processos hidrológicos. A interceptação direta da chuva e do escoamento superficial e subsuperficial, a divergência e a concentração do fluxo d\'água nas estruturas das estradas são as principais mudanças ocorridas. Entre os danos ambientais causados pela introdução das estradas se destacam a redução da qualidade da água e o assoreamento dos cursos d\'água. Diante a necessidade de se entender as funções atribuídas às estradas nas relações entre o manejo florestal e a água, as estradas não pavimentadas da Estação Experimental de Ciências Florestais de Itatinga (EECFI) foram submetidas a duas análises. O trabalho foi dividido em duas partes, a primeira identificou os trechos de estradas suscetíveis à erosão (análise qualitativa) e a segunda parte estimou as taxas de produção de sedimentos e volume de enxurrada nas superfícies das estradas (análise quantitativa). Toda a malha viária da EECFI foi mapeada e digitalizada em plataformas de Sistema de Informações Geográficas (SIG). A partir do modelo digital do terreno e dos mapas de tipo e cobertura de solo foram calculados os quatro indicadores (hidrológicos e topográficos) utilizados na identificação dos trechos com maiores riscos de erosão. Por meio de métodos estatísticos multivariados, todos os indicadores de cada trecho de estrada, simultaneamente, foram divididos em grupos com características similares. A identificação dos grupos de trechos suscetíveis à erosão foi realizada pela interpretação da análise de variância (One Way ANOVA). Para a estimativa proposta na segunda parte do trabalho, foram instaladas 16 parcelas com diferentes declividades, com e sem realização de manutenção nas superfícies das estradas. As taxas de produção de sedimentos e de volume de enxurrada foram analisadas pela análise de covariância, sendo que os efeitos das variáveis e covariáveis foram analisados pelo modelo linear generalizado misto. Os resultados mostraram que tanto os indicadores quanto o método utilizado para a separação foram capazes de identificar dois grupos de trechos com características distintas quanto à suscetibilidade à erosão. Essas características foram proporcionadas pelo posicionamento das estradas em relação às curvas de nível do terreno. A declividade e a manutenção das superfícies das estradas aumentaram significativamente a produção de sedimentos, com maior destaque para as declividades. No que diz respeito ao aumento do volume de enxurrada, somente a realização da manutenção apresentou efeito significativo. A adequação das técnicas de manutenção, assim como a adoção de técnicas complementares em trechos de estradas considerados mais suscetíveis, reduzirão a perda de solo e água e os danos ambientais decorrentes. / Unpaved rural roads generate important growth in developing countries, they play an essential role in the production and marketing of primary products and access to goods and services. Approximately 78.6% of Brazil\'s transport system consists of unpaved roads, not counting the roads of private use of rural properties. In the forest sector the unpaved roads have been the main focus of studies related to erosion, as are the agents that contribute most to the runoff and sediment production. The erosion acceleration provided by roads are linked to changes in hydrological processes. The main changes are rainfall and surface and subsurface flow interception, and the divergence and the concentration of water flow on the roads\' structures. Among the environmental damage caused by the introduction of roads it\'s possible to emphasize the reduction of water quality and stream aggradation. In view of the need to understand the functions of roads in the relations between forest management and water, the unpaved roads of the Experimental Station of Forest Sciences Itatinga (EECFI) were subjected to two analyzes. The study was divided into two parts, the first identified road segments susceptible to erosion (qualitative analysis) and the second part estimated the sediments production rates and volume runoff on road surfaces (quantitative analysis). The entire road network of EECFI was mapped and digitalized using System Geographic Information (GIS) platforms. From the digital elevation model (DEM) and the soil type and land cover maps were calculated four indicators (hydrological and topographical) used in the identification of segments with greater erosion risks. Through multivariate statistical methods, all indicators of each road segment, simultaneously, were divided into groups with similar characteristics. The identification of segments groups susceptible to erosion was performed by the interpretation of the analysis of variance (one way ANOVA). For the estimative proposed in the second part, 16 plots were installed with different slopes, with and without carrying out maintenance on the surfaces of the roads. The sediment production rates and runoff volume were analyzed by analysis of covariance, and the effects of the variables and covariates were analyzed using generalized linear mixed model. The results showed that both the indicators and the method used for the separation were able to identify two segments groups with different characteristics for susceptibility to erosion. These characteristics were provided by the positioning of roads in relation to the terrain contour lines. The slope and the maintenance of road surfaces significantly increased the production of sediments, most notably the slopes. Regarding the increase of the runoff volume, only maintenance activities showed significant effect. The adjustment of maintenance techniques, as well as the adoption of complementary techniques in segments roads considered more susceptible, will reduce the soil and water losses and resulting environmental damages.

Made available in DSpace on 2016-08-17T15:00:40Z (GMT). No. of bitstreams: 1 Lorena Mendes Carreiro.pdf: 2755956 bytes, checksum: 6882b0f4c199c14ab0ebf1c7bf21c1bb (MD5) Previous issue date: 2016-02-23 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Test of risk of contamination of soil and groundwater in Maranhão by organochlorines. Analysis of the susceptibility of ecological interest areas of the state. / Trabalho sobre o risco de contaminação de solos e águas subterrâneas no Maranhão por substâncias organocloradas. Análise da suscetibilidade de áreas de relevante interesse ecológico do Estado.

The world's water resources face unsustainable pressure from population growth, changes in consumption patterns, pollution, and overexploitation. Water resources managers have developed holistic approaches such as IWRM (Integrated Water Resources Management) and, more recently, the WEEF (Water-Energy-Environment-Food) nexus to address the situation. However, their application in day-to-day water resources management is still challenging due to the of little knowledge, data, and tools. One area where that challenge needs practical solutions is reservoir operation. The current study aims to improve the reservoir module in the Soil and Water Assessment Tool (SWAT) so that operation rules that aim to meet various water, food, and electricity objectives can be simulated. The improved SWAT model is used to simulate the management of the Sélingué reservoir in Mali, West Africa. The reservoir operation was simulated under three different operation rules: 1) priority to monthly hydropower production (HPP) target (rule 1); 2) respect of predefined monthly target storage (rule 2); 3) priority to downstream environmental flow, irrigation, and municipal water demands (rule 3). Results show that when priority is given to the HPP target (rule 1), 98.3% of the electricity demand is met. At the same time, the dam can supply 81.72% of the water demand to maintain environmental flow and sustain irrigation and municipal water consumption. It also ensures water availability with an annual target storage deviation estimated at 1.8%. When rule 2 is implemented, a gap of 8.5% between electricity production and electricity demand is observed. Rule 2 also failed to sustain environmental flow and supply flow for irrigation and municipal consumption as a gap of 15.39% between the supply and the demand was observed. Similarly to rule 1, It ensures water availability with an annual target storage deviation estimated at 1.25%. When rule 3 is enforced (i.e., the priority is given to environmental flow, irrigation, and municipal water demands) the reservoir can maintain the environmental flow and maintain irrigation, and municipal water requirements with a gap of 17.7% between the supply and the demands. However, HPP production decreases with a gap of 12.56% between the electricity supply and demand. Its capacity to supply water in the long term is low as it has the highest target storage deviation with a value of 18%. These results indicate that rule 1 offers more guarantees considering the food and electricity security and environmental challenges. Note that the simulations are done assuming that these rules are systematically followed. In practice, decision-makers can deviate from a rule in exceptional circumstances to maximize benefits or avert unwanted consequences. Finally, a decision support system (DSS) was developed to assist decision-makers in selecting efficient reservoir operation policies for multipurpose reservoirs combining HPP and irrigation.

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