Aplicação da RUSLE a uma pequena bacia hidrográfica da Amazônia

A Amazônia vem sofrendo severas mudanças provocadas por atividades antrópicas, dentre as quais se destaca a transformação de áreas de floresta em áreas de uso agropecuário, resultando na intensificação dos processos erosivos. A erosão, com destaque ao arraste de partículas pelo escoamento superficial, causa redução da fertilidade do solo, prejudicando a produtividade agrícola, além de impactar a qualidade e quantidade dos recursos hídricos superficiais, fato agravado pelo forte regime pluviométrico e solos naturalmente pobres da região. Nesse contexto, o conhecimento dos processos erosivos, através da utilização de modelos matemáticos para predição da perda de solo, auxilia na determinação de práticas de manejo para o uso sustentável dos recursos naturais. A presente pesquisa buscou avaliar a aplicabilidade do modelo empírico RUSLE (Revised Universal Soil Loss Equation) na região, o qual considera a interação entre a energia da chuva, as características de solo e relevo, assim como os usos e manejos praticados. A pesquisa aplicou a RUSLE no trecho superior da bacia do igarapé da Prata, com uma área aproximada de 37 km^², que fica localizada no município de Capitão Poço/PA, aproximadamente 160 km da capital Belém, na Meso Região Nordeste Paraense. A metodologia empregada constou da construção de uma base de dados georreferenciada, formada a partir de fontes públicas, que passaram por adequações para inserção no ambiente SIG, que quando combinados permitiram a geração de um mapa de perda de solo da área de estudo. A pequena bacia do igarapé da Prata apresentou valores da perda de solo que variaram entre 0,004 e 72,48 t/ha.ano, com uma média de 5,12 e desvio padrão de 6,97, onde aproximadamente 12% de sua área total apresentam riscos ambientais devido aos processos erosivos. E o percentual restante, para não sofrer riscos, depende de boas práticas conservacionistas.

Diagnóstico visando planejamento ambiental da alta Bacia do Ribeirão Areia Dourada, Marabá Paulista (SP)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Identificação de áreas sujeitas a processos erosivos na área urbana do município de Aparecida, SP

Historically, in Brazil, the process of urbanization and city growth was due to the intense migration of rural population to urban areas, especially in the last thirty years. This move, combined with a lack of planning, allowed the occupation of areas with potential for occurrences of erosion. The city of Aparecida, SP can be cited as an example of this process. These irregular occupations generate large material damage and human losses conditioned on mass movement of soil, resulting from the development of erosive processes. So, it is of great importance to physical characterization and identification of these areas within the same city map as a way to minimize the effects and mitigate the consequences of events. Thus, this work presents a series of graduate field campaigns, geotechnical laboratory testing and consultation with representative maps of the physical environment, as a means conclusive for delimintation of areas with potential risk for the occurrence of erosion, especially in areas undergoing urban expansion of the city Aparecida, SP. These areas were determined some geotechnical properties of soils present, evaluating the potential erodibility of them. Also presented are the descriptions of the main characteristics of these areas identified as being at risk, along with proposals to avoid or minimize the impact of problems related to erosion processes on the local population

Propostas de Adequação Ambiental para a Cidade da Criança de Presidente Prudente - SP

The environmental issue has been considered of fundamental importance for the well being of the present and future generations and is inserted into the commitment of political parties at federal, state and municipal government programs, into the interests of popular organizations and business planning. The Parque Ecológico Cidade da Criança is one of the most sought after places for visitation at Presidente Prudente – SP. Located outside the Raposo Tavares Highway, next to the exhibition grounds and beside the agricultural school, has more than 30 acres of area with an infrastructure designed for recreation and leisure activities for all ages and has received new investment of the public power. Given the importance of the ecological aspects, the objective of this work is to perform an environmental diagnosis in order to be able to submit proposals for solving the problems encountered and improve the use of the environmental resources. Therefore, the study was divided into three foci: sewage disposal, erosion process and control of the stormwater drainage system. It was checked the discharge of sewage from the restaurant on exposed soil, erosion processes that develop at the camel and llama cages ground and erosion processes resulting from the convergence of the stormwater in the highest region of the park. Based on these studies, proposals of solution were made for each case, having considered the effectiveness of the project

Identificação de áreas de risco na região urbana do município de Guaratinguetá, SP, quanto à ocorrência de inundações e processos erosivos

The city of Guaratinguetá, SP, presents in its history, several instances of property damage and human losses, conditional on the event of flooding and mass movement of soil, resulting from the development of erosion processes. The extent and severity of these events that affect humans and their properties is the result of the illegal occupation of these areas as potential geohazard. Thus, it is of great importance to physical characterization and identification of such areas within the map of the same city as a way to minimize the effects and mitigate the consequences of these events. Thus, this graduate report presents a series of field campaigns, geotechnical laboratory testing, consultation with maps and satellite images, representative of the physical environment, and the city plan as a means conclusive for the delimitation of risk areas with potential for occurrence of erosion and / or flooding on the map representing the urban area of Guaratinguetá, SP. Also featured are the descriptions of the main characteristics of those areas identified as being at risk, along with proposals to avoid or minimize the impact of problems related to flooding and erosion processes on the local population

Análise morfotectônica do Planalto Ocidental Paulista, ao sul do Rio Tietê: indicadores de deformações neotectônicas na fisiografia da paisagem

Pós-graduação em Geologia Regional - IGCE

Avaliação de métodos de proteção para taludes em estrada não-pavimentada

This work presents the results of the efficiency of three protection methods of roads slopes, against the development of erosion processes.The methods anlyzed were: (1) grass planting "San Carlos" (Axonopus compressus), (2) litter, composed of remains of branches and leaves of eucalyptus E. Grandis, and (3) Compacted soil cover with a local soil with properties more resistant to erosion processes.The experiment consisted of assembly of four rectangular cells with 6 meters, three for protection systems in study and one was kept unprotected to evaluate the efficiency of the methods in study.The determination of the amount of eroded sediment was based on the sum of the solids in suspension and stored sediments in the geotextile bags.The results showed that, compared to the unprotected cell, the litter obtained a reduction of soil loss of 90%, while the grass enveloped and reduced 80% and 65% respectively.

Spatial distribution of runoff depth from a watershed located in a cuesta relief area of São Paulo State, Brazil

This study was undertaken in a 1566 ha drainage basin situated in an area with cuesta relief in the state of São Paulo, Brazil. The objectives were: 1) to map the maximum potential soil water retention capacity, and 2) to simulate the depth of surface runoff in each geographical position of the area based on a typical rainfall event. The database required for the development of this research was generated in the environment of the geographical information system ArcInfo v.10.1. Undeformed soil samples were collected at 69 points. The ordinary kriging method was used in the interpolation of the values of soil density and maximum potential soil water retention capacity. The spherical model allowed for better adjustment of the semivariograms corresponding to the two soil attributes for the depth of 0 to 20 cm, while the Gaussian model enabled a better fit of the spatial behavior of the two variables for the depth of 20 to 40 cm. The simulation of the spatial distribution revealed a gradual increase in the depth of surface runoff for the rainfall event taken as example (25 mm) from the reverse to the peripheral depression of the cuesta (from west to east). There is a positive aspect observed in the gradient, since the sites of highest declivity, especially those at the front of the cuesta, are closer to the western boundary of the watershed where the lowest depths of runoff occur. This behavior, in conjunction with certain values of erodibility and depending on the land use and cover, can help mitigate the soil erosion processes in these areas.

Aplicação de análise multicriterial para determinação de áreas prioritárias à recomposição florestal

Using the Geographic Information System (GIS) and taking into account its capability to analyze spatial data, a database of updated spatial data from the sub-basin of the Descalvado stream, Botucatu, SP, was developed to provide an evaluation and diagnosis of the area concerning land use and the degradation processes therein. Through GIS, priority areas for forest recovery were defined by Multicriteria Evaluation and using the Ordered Weighted Average method. The latter allows the decision maker to define the area to be recovered, facing limitation of resources, among one of the proposed scenarios, or do it in stages. The study showed that there are accelerated erosion processes in the headwaters of the springs of water bodies; there is also fragmentation of native vegetation, especially in hillside areas, and little presence of native vegetation in riparian areas. The application of the multicriteria analysis using the Ordered Weighted Average was important as it systematized and discriminated scenarios of priority for forest recovery.

Monitoramento e avaliação de processos erosivos marginais em reservatórios de usinas hidrelétricas por meio de varredura a laser

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Problemática ambiental en la isla de La Graciosa: ¿Hay déficit de arena actual en sistemas playa-duna?

[ES] La isla La Graciosa está situada al noroeste de Lanzarote y tiene una extensión de 27,05 km2. Se trata de un área que presenta un alto valor ecológico pues está protegida a través de diferentes figuras tales como: Parque Natural y Reserva Marina del Archipiélago Chinijo, Reserva de la Biosfera de Lanzarote, Zona de Especial Protección de aves (ZEPA) y Zona de Especial Conservación (ZEC), entre otras. En la isla hay varios sistemas playa-duna tanto en la mitad nororiental de la isla (Las Conchas, Lambra y El Jablillo) como en su parte meridional (Barranco de Los Conejos, Las Caletas, El Salado y Francesa). Algunas de las playas muestran evidencias de un déficit sedimentario pues tienen una reducida o nula entrada de sedimentos arenosos al sistema y/o muestran procesos erosivos que hacen aparecer el substrato rocoso. Además, se observa en el interior de la isla la estabilización de los mantos eólicos por la vegetación. Estos ambientes eólicos costeros son esenciales, tanto para la preservación de los ecosistemas protegidos, como para la actividad turística insular. En este contexto se están desarrollando investigaciones multidisciplinares para elaborar un diagnóstico científico de esta problemática ambiental, determinando si las causas de este déficit sedimentario son naturales o antrópicas, y proponer soluciones al respecto.

Historisches Grabenreißen im Wassereinzugsgebiet der Aar zwischen Wiesbaden und Limburg

Im Wassereinzugsgebiet der Aar zwischen Taunuskamm und Limburger Becken wurden 242 Erosionsschluchten, so genannte Runsen kartiert. Die vorgefundenen geomorphologischen Formen sind zum Teil mehr als 15 Meter tief, kerben- oder kastenförmig. Einige führen ein zeitweise oder ständig fließendes Gerinne. Die Untersuchung acht verschiedener Einzelbeispiele mit geomorphologischen, bodenkundlichen und kulturhistorischen Methoden ergab, dass die Erosionsschluchten in geschichtlicher Zeit entstanden sind. Damit wurden die Ergebnisse von BORK 1988, 1985, BORK et al. 1998, BAUER 1995, 1993, SEMMEL 1963, HEMPEL 1954, 1954 und HARD 1970 weitgehend bestätigt. Die Runsen an der Aar und ihrer Nebenbäche sind das Ergebnis exzessiver Erosionsprozesse, die in Folge einer erheblichen Übernutzung der Landschaft durch Köhlerei, Eisenerzverhüttung und Landwirtschaft hauptsächlich im 17. und 18. Jahrhundert ausgelöst wurden. Dabei kommt der seit 1656 betriebenen Michelbacher Hütte als landesherrliches Eisenwerk eine besondere Rolle zu. Ein weiterer Einfluss geht auf die spezifische Geofaktorenkonstellation im Untertaunus zurück. Die dort verbreiteten stark tonig verwitterten Schiefer und erodierten Parabraunerden fördern den Oberflächenabfluss, der während zeitweise auftretender Starkregenereignisse an den Hängen zum Einreißen von Erosionsschluchten führen kann . Zur Untersuchung des Phänomens wurden sowohl geomorphologische und bodenkundliche als auch historisch-kulturlandschaftgenetische Methoden herangezogen. Neben der bodenkundlichen Beprobung zahlreicher Aufschlüsse wurden auch Analysen mittels der Radiokarbonmethode, Schwermineralanalysen, Kohlholzspektren historischer Meilerplätze und die Auswertung von Archivunterlagen als Methoden herangezogen. Als grundlegendes Ergebnis liefert die vorliegende Arbeit einen umfassenden Abriss der Nutzungsgeschichte im Wassereinzugsgebiet der Aar von vorgeschichtlicher Zeit bis zum heutigen Tage. Zudem werden die naturräumlichen Einflussfaktoren, die die Entstehung von Erosionsschluchten erst ermöglichen, auf umfassende Weise dargestellt. Zwei Exkurse behandeln die Bedeutung der spätmittelalterlichen Landwehr bei Hennethal, die während der Geländearbeiten entdeckt wurde sowie die Entstehung und zeitliche Einordnung der Auelehme im Aartal.

Climate and vegetation changes during the Lateglacial and early–middle Holocene at Lake Ledro (southern Alps, Italy)

Adding to the on-going debate regarding vegetation recolonisation (more particularly the timing) in Europe and climate change since the Lateglacial, this study investigates a long sediment core (LL081) from Lake Ledro (652ma.s.l., southern Alps, Italy). Environmental changes were reconstructed using multiproxy analysis (pollen-based vegetation and climate reconstruction, lake levels, magnetic susceptibility and X-ray fluorescence (XRF) measurements) recorded climate and land-use changes during the Lateglacial and early-middle Holocene. The well-dated and high-resolution pollen record of Lake Ledro is compared with vegetation records from the southern and northern Alps to trace the history of tree species distribution. An altitudedependent progressive time delay of the first continuous occurrence of Abies (fir) and of the Larix (larch) development has been observed since the Lateglacial in the southern Alps. This pattern suggests that the mid-altitude Lake Ledro area was not a refuge and that trees originated from lowlands or hilly areas (e.g. Euganean Hills) in northern Italy. Preboreal oscillations (ca. 11 000 cal BP), Boreal oscillations (ca. 10 200, 9300 cal BP) and the 8.2 kyr cold event suggest a centennial-scale climate forcing in the studied area. Picea (spruce) expansion occurred preferentially around 10 200 and 8200 cal BP in the south-eastern Alps, and therefore reflects the long-lasting cumulative effects of successive boreal and the 8.2 kyr cold event. The extension of Abies is contemporaneous with the 8.2 kyr event, but its development in the southern Alps benefits from the wettest interval 8200-7300 cal BP evidenced in high lake levels, flood activity and pollen-based climate reconstructions. Since ca. 7500 cal BP, a weak signal of pollen-based anthropogenic activities suggest weak human impact. The period between ca. 5700 and ca. 4100 cal BP is considered as a transition period to colder and wetter conditions (particularly during summers) that favoured a dense beech (Fagus) forest development which in return caused a distinctive yew (Taxus) decline.We conclude that climate was the dominant factor controlling vegetation changes and erosion processes during the early and middle Holocene (up to ca. 4100 cal BP).

Orbital changes, variation in solar activity and increased anthropogenic activities: controls on the Holocene flood frequency in the Lake Ledro area, Northern Italy

Adding to the on-going debate regarding vegetation recolonisation (more particularly the timing) in Europe and climate change since the Lateglacial, this study investigates a long sediment core (LL081) from Lake Ledro (652ma.s.l., southern Alps, Italy). Environmental changes were reconstructed using multiproxy analysis (pollen-based vegetation and climate reconstruction, lake levels, magnetic susceptibility and X-ray fluorescence (XRF) measurements) recorded climate and land-use changes during the Lateglacial and early-middle Holocene. The well-dated and high-resolution pollen record of Lake Ledro is compared with vegetation records from the southern and northern Alps to trace the history of tree species distribution. An altitudedependent progressive time delay of the first continuous occurrence of Abies (fir) and of the Larix (larch) development has been observed since the Lateglacial in the southern Alps. This pattern suggests that the mid-altitude Lake Ledro area was not a refuge and that trees originated from lowlands or hilly areas (e.g. Euganean Hills) in northern Italy. Preboreal oscillations (ca. 11 000 cal BP), Boreal oscillations (ca. 10 200, 9300 cal BP) and the 8.2 kyr cold event suggest a centennial-scale climate forcing in the studied area. Picea (spruce) expansion occurred preferentially around 10 200 and 8200 cal BP in the south-eastern Alps, and therefore reflects the long-lasting cumulative effects of successive boreal and the 8.2 kyr cold event. The extension of Abies is contemporaneous with the 8.2 kyr event, but its development in the southern Alps benefits from the wettest interval 8200-7300 cal BP evidenced in high lake levels, flood activity and pollen-based climate reconstructions. Since ca. 7500 cal BP, a weak signal of pollen-based anthropogenic activities suggest weak human impact. The period between ca. 5700 and ca. 4100 cal BP is considered as a transition period to colder and wetter conditions (particularly during summers) that favoured a dense beech (Fagus) forest development which in return caused a distinctive yew (Taxus) decline.We conclude that climate was the dominant factor controlling vegetation changes and erosion processes during the early and middle Holocene (up to ca. 4100 cal BP).

Quantitative 3D strain analysis in analogue experiments: Integration of X-ray computed tomography and digital volume correlation techniques

The combination of scaled analogue experiments, material mechanics, X-ray computed tomography (XRCT) and Digital Volume Correlation techniques (DVC) is a powerful new tool not only to examine the 3 dimensional structure and kinematic evolution of complex deformation structures in scaled analogue experiments, but also to fully quantify their spatial strain distribution and complete strain history. Digital image correlation (DIC) is an important advance in quantitative physical modelling and helps to understand non-linear deformation processes. Optical non-intrusive (DIC) techniques enable the quantification of localised and distributed deformation in analogue experiments based either on images taken through transparent sidewalls (2D DIC) or on surface views (3D DIC). X-ray computed tomography (XRCT) analysis permits the non-destructive visualisation of the internal structure and kinematic evolution of scaled analogue experiments simulating tectonic evolution of complex geological structures. The combination of XRCT sectional image data of analogue experiments with 2D DIC only allows quantification of 2D displacement and strain components in section direction. This completely omits the potential of CT experiments for full 3D strain analysis of complex, non-cylindrical deformation structures. In this study, we apply digital volume correlation (DVC) techniques on XRCT scan data of “solid” analogue experiments to fully quantify the internal displacement and strain in 3 dimensions over time. Our first results indicate that the application of DVC techniques on XRCT volume data can successfully be used to quantify the 3D spatial and temporal strain patterns inside analogue experiments. We demonstrate the potential of combining DVC techniques and XRCT volume imaging for 3D strain analysis of a contractional experiment simulating the development of a non-cylindrical pop-up structure. Furthermore, we discuss various options for optimisation of granular materials, pattern generation, and data acquisition for increased resolution and accuracy of the strain results. Three-dimensional strain analysis of analogue models is of particular interest for geological and seismic interpretations of complex, non-cylindrical geological structures. The volume strain data enable the analysis of the large-scale and small-scale strain history of geological structures.