Processos erosivos podem gerar grandes prejuízos ambientais e econômicos. É importante que projetos de controle de erosão tenham uma abordagem holística, considerando aspectos econômicos, sociais, ecológicos e paisagísticos. A sub-bacia do Alto Rio Grande apresenta uma elevada incidência de boçorocas de grande porte. No município de Nazareno/MG, foi realizado um projeto de controle na Boçoroca do Córrego do Cravo, entretanto, após a finalização das obras, houve dois grandes escorregamentos na área. Realizou-se uma análise geológico-geotécnica da boçoroca a fim de se entender os motivos pelos quais ocorreram os escorregamentos e propor técnicas de bioengenharia de solos para a estabilização dos taludes. Foram realizadas campanhas de campos e ensaios laboratoriais com amostras de pontos com diferentes condições de estabilidade. Realizaram-se ensaios de determinação de massa específica, granulometria, limites de consistência, erodibilidade, adsorção de azul de metileno, ATD, ATG e DRX. Também se realizou um levantamento bibliográfico de técnicas de bioengenharia de solos para estabilização de taludes em boçorocas preferencialmente em condições similares às da área de estudo. A maior parte da feição erosiva consiste de uma camada de solo laterítico sobre um saprolito de gnaisse. O solo laterítico é majoritariamente argiloso com presença de caulinita e óxidos, que conferem resistência ao material. Já o saprolito é siltoso, friável e apresenta argilominerais mais ativos. O projeto realizado previamente utilizou técnicas de baixo custo e impacto ambiental e controlou o avanço da feição erosiva, entretanto, apresentou algumas carências quanto à estabilização dos taludes. Concluiu-se que os escorregamentos podem ter ocorrido devido à saturação do saprolito e consequente instabilização de todo o maciço. A alta declividade dos taludes e a presença de planos preferenciais de ruptura também podem ter contribuído para a ocorrência dos escorregamentos. Propôs-se o retaludamento das encostas e o uso de técnicas de bioengenharia de solos para a estabilização do solo e incremento da biodiversidade local. / Erosion can generate great environmental and economic losses. It is important that erosion control projects have a holistic approach, considering economic, social, ecological and landscape aspects. The Alto Rio Grande hydrographic basin presents a high incidence of large gullies. A control project was the done in Córrego do Cravo Gully, city of Nazareno/MG. However, after the completion of the works, there were two major landslides in the area. The geological and geotechnical analysis of the gully was accomplished in order to understand the reasons why the landslides occurred and to propose soil bioengineering techniques for slope stabilization. Field visits and laboratory tests on samples from places with different stability conditions were performed. The tests performed were density determination, grain size analysis, liquid limit, plastic limit, erodibility, methylene blue adsorption, DTA, TGA and XRD. It was also made a literature review of soil bioengineering techniques for slope stabilization in gullies preferably under similar conditions to the study area. Most of the studied gully consists of a laterite layer over a gneiss saprolite. The laterite soil is mostly clay with presence of kaolinite and oxides, which provide resistance to the material. The saprolite is silty, friable and presents more active clay minerals. The previous conducted project used low cost and low environment impacts techniques which contained the advance of erosion, however, it presented some deficiencies in slope stabilization. It was concluded that the landslides may have occurred due to saturation of the saprolite and consequent instability of the whole soil massif. The high declivity of the slopes and the presence of rupture surfaces may also have contributed to the occurrence of the landslides. It was proposed the change of the slope geometry and the use of soil bioengineering techniques for soil stabilization and increase of local biodiversity.

Entre os parâmetros da USLE (Universal Soil Loss Equation), método mais utilizado na estimativa das perdas de solo por erosão hídrica, a erodibilidade do solo, representada pelo fator K e definida como a taxa de solo perdida por unidade de índice de erosividade, em parcela unitária considerada como padrão (Wischmeier et al., 1971), é o único intrínseco ao solo. Nessas condições padrão o valor encontrado é considerado como o real valor de K. Pelas dificuldades experimentais para obtenção do valor de K para todos os solos, esse fator é geralmente estimado por equações matemáticas empíricas com base em atributos físicos, químicos e mineralógicos do solo. O presente trabalho trata da avaliação de oito métodos de estimativa do fator K da USLE, tomando-se por base estimativas das taxas de erosão avaliadas pelo método do 137Cs. Foram utilizadas oito parcelas padrão de avaliação de perdas de solo e seis transeções demarcadas no campo, em diferentes solos. Nas parcelas padrão, as taxas de erosão medidas diretamente foram comparadas com as estimadas pelo método do 137Cs e os resultados indicaram uma boa concordância. Os valores de K, estimados pelos diferentes modelos, para o solo da parcela, foram comparados diretamente com o valor medido e mostram que os métodos propostos por Wischmeier et al. (1971) e Denardin (1990) desenvolvido para solos do Brasil, são os que mais se aproximam do valor medido. Os mesmos valores de K foram também avaliados por meio da comparação entre as taxas de erosão estimadas pela USLE e pelo método do 137Cs, tendo sido obtidos resultados semelhantes aos da avaliação direta. Essa última forma de avaliação dos métodos de estimativa do fator K foi aplicada também em seis transeções demarcadas em diferentes solos. Devido às grandes limitações associadas aos dois métodos, os resultados mostram uma grande discrepância entre as taxas de erosão estimadas pela USLE e pelo 137Cs o que inviabilizou a comparação proposta dos modelos. / Among the Universal Soil Loss Equation (USLE) parameters, the soil erodibility factor (K), defined as the rate of soil loss per unit of area and per unit of erosivity index for a specific soil as measured on unit plot (Wischmeier & Smith, 1978), is the only soil intrinsic factor. The K values determined on standard unit plots are considered as the real K values. However, K factor can be also estimated by empirical models based on physical, chemical and mineralogical soil attributes. Eight of such empirical methods for K factor estimation were evaluated by comparing the rates of soil loss calculated by USLE and 137Cs fallout redistribution analysis. This procedure was applied both in eight standard erosion plots and six field transects on different soils. In the standard erosion plots the measured soil erosion rates were compared with the rates estimated by the 137Cs method and the results indicate a good relationship. The K values estimated by the different models for the specific soil of the standard plots were compared with the measured K value. The results obtained by the models proposed by Wischmeier et al. (1971) and Denardin (1990) for Brazilian soils were more close to the measured K value. The same K values were also evaluated by comparing the soil erosion rates estimated by USLE and 137Cs methods and the results are in agreement with the direct comparison. This procedure was also applied for the evaluation of K estimation models on the field transects. Due to the limitations associated to both models, the soil erosion rates estimated by USLE and 137Cs methods were very discrepant which did not allow the comparison of K estimation methods when applied for the soils of the transects.

Submitted by Rosangela Silva (rosangela.silva3@unioeste.br) on 2017-08-31T19:16:21Z No. of bitstreams: 2 Luana Salete Celante.pdf: 1304989 bytes, checksum: 465dd26385572a31edf48194fc31eba5 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2017-08-31T19:16:21Z (GMT). No. of bitstreams: 2 Luana Salete Celante.pdf: 1304989 bytes, checksum: 465dd26385572a31edf48194fc31eba5 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2017-02-23 / Fundação Araucária (FA) / Erosive processes have been a constant concern in relation to soil management and use, especially with reflections on crop yield and environmental quality, mainly due to the soil and water losses from runoff. Thus, the objective of the present work was to quantify soil and water loss rates in a clayey Oxisol under no-tillage system, relating these rates to soybean grain yield and to develop models that associate water and soil loss rates depending on the slope variation. The experimental area is located in a municipality of Cascavel - PR, commercial crop of soybeans. The treatments were four pre-established slope of 3.5%, 8.2%, 11.4% and 13.5% which were monitored water and soil loss rates at different rainfall events. The soil and water losses were collected in gutters made of PVC and stored in containers for measurement and analysis. The obtained data were statistically evaluated by the Tukey test. There was no significant influence of the slopes used in the different rain intensities, in the water and soil losses. There was a difference in soybean grain yield in which treatments with slopes 8.2% and 13.5% showed higher values. The loss of soil and water presented a higher correlation with macroporosity and soil density together. The soybean grain yield presented a higher linear correlation with the loss of water and soil. The low water and soil losses demonstrate the soil capacity, managed under the no-tillage system, to minimize environmental impacts. / Os processos erosivos têm sido alvo de preocupação constante em relação ao manejo e uso do solo, em especial com reflexos na produtividade de culturas e na qualidade ambiental, principalmente pela perda de solo e água pelo escoamento superficial. Desse modo, o objetivo do presente trabalho foi quantificar as taxas de perdas de solo e água em um Latossolo argiloso sob sistema plantio direto, relacionando estas taxas com o rendimento de grãos de soja e desenvolver modelos que associem as taxas de perda de água e solo em função da variação da declividade. A área experimental localizou-se no município de Cascavel – PR, em lavoura comercial de soja. Foram consideradas 4 declividades pré-estabelecidas de 3,5%, 8,2% 11,4% e 13,5% como tratamentos, em que foram monitoradas as taxas de perdas de água e solo com as precipitações ocorridas durante o estudo. A água escoada em cada parcela foi recolhida em calhas confeccionadas de PVC e armazenadas em recipientes para quantificação e análise. Os dados obtidos foram avaliados estatisticamente pelo teste de Tukey. Não houve influência significativa das declividades utilizadas nas diferentes intensidades de chuva, nas perdas de água e solo. Houve diferença no rendimento de grãos de soja em que os tratamentos com declividades 8,2% e 13,5%, apresentaram maiores valores de rendimentos. A perda de solo e água apresentaram maior correlação com a macroporosidade e a densidade de solo em conjunto. O rendimento de grãos de soja apresentou maior correlação linear com a Perda de água e de solo. As baixas perdas de água e solo demonstram a capacidade do solo, manejado sob sistema plantio direto, de minimizar impactos ambientais.

A new model of the erosion by water of cohesive soils is developed using physical principles. The theoretical framework which is developed recognises the changing nature of the eroding surface of a soil. Raindrop impact and overland flow are considered to act upon a soil surface so removing soil from the cohesive original (or parent) soil. Once this soil enters the overland flow, either as aggregates or primary particles, it is considered to return to the soil bed, from which it may be re-removed. The development of a deposited layer makes it necessary to distinguish between processes removing sediment from the original soil and those processes removing the deposited layer. This layer, being formed by the relatively gentle action of deposition during the current erosion event, is presumed cohesionless. The physical properties of the original soil and the deposited layer are considered to be very different. The development of two experimental apparatus, a rainfall/runoff simulator and a settling tube for the measurement of aggregate settling velocities, is first described. Experimental investigations, using these apparatus, and field observations to inform the description of the erosion and deposition processes, are then presented. The processes by which rainfall impact removes sediment from the original soil and the deposited layer are termed rainfall detachment and rainfall re-detachment respectively. Initially, descriptions of these processes in the presence of deposition, are combined in a model describing net rainfall detachment when removal of sediment from the flow bed by overland flow is not occurring. The developriient of the deposited layer is considered both quantitatively and qualitatively. The solution of the equation describing mass conservation is then given for the equilibrium situation when the mass of the deposited layer, and therefore the sediment concentration, is constant with respect to time. The processes by which overland flow removes sediment from the original soil and the deposited layer are termed entrainment and re-entrainment. The work done by the process of entrainment is considered to be done wholly against the cohesive strength of the original soil. In contrast to the process of entrainment, the work done in re-entraining sediment from the deposited layer is considered only to be done against gravity. The resulting description of these processes is then combined with the previous descriptions of rainfall detachment, rainfall re-detachment and deposition and with the equation describing the conservation of mass of sediment within any arbitary number of size (or settling velocity) classes. A plane geometry model Is developed in which the surface water flow is considered to be uniformily distributed across a plane slope on which all processes act. When the mass of the deposited layer is steady, two possible forms of equilibrium are shown to exist. When the coverage of the original soil by deposited layer is partial, the sediment concentration is limited by the removal of the cohesive original soil by entrainment and rainfall detachment, in the presence of deposition. This situation is termed 'source limiting' and is shown to provide a lower limit to sediment concentration. When the coverage of the deposited layer is complete so that entrainment and rainfall detachment of the original soil are considered not to occur, then the ability of the erosive agents to re-entrain and re-detach sediment in the presence of deposition limits sediment concentration. This situation, termed 'transport limiting', is shown to provide a practical upper limit to sediment concentration. This plane geometry flow model is followed by a revised model in which all processes are considered to occur but the flow of water on a plane surface is modified by the formation of rills. In this 'detailed geometry model' the spatial distribution of the erosive agents is shown to have a marked influence on the resulting processes and sediment concentrations. A potential description of the sediment transport across a change in land slope is also developed. Finally, a discussion of this new modelling approach is presented in which the conceptual developments of this thesis are considered and future developments are suggested. This discussion also includes a comparison of the outcomes of this new work with similar erosion models.

Disputats. Universität Hohenheim, 2003. / Haves kun i elektronisk udg.

Thesis(M.S.)--Auburn University, 2005. / Abstract. Vita. Includes bibliographic references (p.86-89).

The aim of this work is to clarificate water erosion issues, which were compared by study and analysis of history in a selected area. In the literature review of this study, evolution of agriculture based on land and political ownerships is described. The next things explained in this study are erosion, its causes, repercussions and ways how to fight erossion. The chosen area was cadastral territory Bavorovice. There were used historical maps from years 1827 and 1972, which were landed by cadastral workspace in České Budějovice. For the analysis, historical maps from years 1827 and 1972 were provided by cadastral office in České Budějovice. The maps were compared with a current state after finished KoPÚ. In those maps as well as in the actual cadastral map a few land fields were selected for calculation of average soil loss per year in solved time periods. For the calculation, (of average soil loss) universal equation for average soil loss from land by Wishmaier and Smith was used, which is used. This equation is used for KoPÚ projects as well. The results were evaluated and compared in conclusion of this study.

This diploma thesis is focused on antierosion protection issues used on a general landscaping model project. The first part deals with the theory of erosion, especially the water erosion, antierosion precaution and landscaping. The second part deals with practical calculation of water erosion using the Wischmeier-Smith equation. In case of exceeding the maximum annual soil loss, proper antierosion precaution is proposed.

The graduation thesis analyzes water erosion issue, especially by calculating average earth annual loss using the Wischmeier Smith universal equation. Primary task was to assess and evaluate erosion phenomenon on the model basins' borderlines and review the hydrological and administrative teritorial units overlay from the perspective of rainfall runoff. Secondary task was to explore the possibility and suitability of increasing the rainfall erosion efficiency factor by doubling.

This thesis solves problems of erosion protection in land consolidation on three projects of selected model complex land adjustment. The first part deals with the theory of land consolidation, water erosion and potential erosion protection applicable to the design complex of land adjustment. In the second part we discuss practical solutions for erosion control, its calculation and the proposed erosion control plan in relation to the collective model in various projects.