Rozprawy doktorskie na temat „Erosion mapping”

Federal, state and local governments are increasingly focused on the effects of development on water quality and quantity. With waterbodies being especially sensitive to certain pollutants, such as sediment and nutrients, regulations have been put in place to control the amount of pollutant that gets discharged. Sediment is a cause for concern as it originates during both rural and urban activities, and often carries other pollutants (metals, nutrients, etc.) with it. Existing erosion models focus primarily on estimating erosion from agricultural watersheds. Methods are needed to predict areas with high erosive potential (EP) in urban watersheds. Highlighting highly erosive areas in urbanized watersheds allows for the prioritization of maintenance and installation of Stormwater Control Measures (SCMs), and monitoring of sediment by municipal planners and engineers. This study utilizes commonly available geospatial layers in conjunction with a computational procedure to compute relative EP risk throughout a target urban watershed. A case study of the developed methodology was performed on a watershed in Blacksburg, VA, to generate EP risk maps. Results of the study indicate areas of erosive potential within the target watershed and provide a methodology for creating erosion potential risk maps for use by municipal planners and engineers
Master of Science

Master of Arts
Geography
Charles W. Martin
Tuttle Creek Dam was built in 1962 after near-record flooding in the Kansas River watershed. It has been in operation for over 50 years. In that time, nearly half of its storage capacity has been filled by sediment, reducing its ability to serve its intended purpose under current operations. The Corps of Engineers authorized a study to examine the sediment in Tuttle Creek Lake and determine management strategies to extend its lifespan. This report examines the erodibility of the sediment as a function of depth and distance to dam. Eight sediment cores were tested and analyzed for two erodibility parameters, critical shear stress and erodibility coefficient. After directly comparing these parameters it was determined that Tuttle Creek Lake sediment ranges from erodible to very erodible regardless of depth or location. Analyzing for locational and depth patterns in erodibility coefficients indicated that both influence the erodibility of sediment, with depth being the stronger factor. These results indicate that locations further upstream from the dam and greater depths are the least erodible. Sedimentation patterns were mapped onto a three dimensional model in ArcMap. It is hoped that this research will assist Corps of Engineers leadership in deciding which management practices to pursue for Tuttle Creek Lake.

Este trabalho teve como objetivo fazer um inventário das feições erosivas lineares da alta bacia do ribeirão Araquá, municípios de São Pedro e Charqueada/SP, com base em técnicas cartográficas e aerofotogramétricas analógicas e digitais. O levantamento foi realizado em 2 escalas de abordagem diferentes: 1:50.000 (semi-detalhe) e 1:15.000 (detalhe). Na escala de semi-detalhe, produziu-se uma carta hipsométrica, uma carta clinográfica e um mapa morfológico, onde foram representadas as feições erosivas. Esses produtos, aliados com as informações sobre solos, litologia e o uso da terra, deram origem ao mapa morfopedológico da sub-bacia. Com base nesse mapa, foi definida a sub-bacia do Córrego do Querosene para o estudo em escala de detalhe. Na sub-bacia do Córrego do Querosene foram produzidas as cartas hipsométrica e clinográfica e os mapas de morfologia do relevo, solos, uso da terra e formas erosivas lineares. O levantamento do uso da terra e das formas erosivas lineares foi realizado com base em fotografias de 4 períodos diferentes, 1962 (1:25.000), 1978 (1:35.000), 1995 (1:25.000) e 2006 (1:30.000). Esse diagnóstico possibilitou realizar correlações das formas erosivas com as características do meio físico, o que deu origem a um mapa de suscetibilidade à erosão, além de ter permitido uma avaliação da evolução temporal das feições. Os resultados mostraram que a área atingida por sulcos diminuiu 38,18% no período de 1962 a 2009. Em contrapartida, as afetadas por linhas de pisoteio subiram 137%. No mesmo período, o número de ravinas aumentou em 87,5%, e as voçorocas cerca de 300%. Os dados mostraram também que as ravinas e voçorocas se instalaram preferencialmente em setores côncavos das vertentes, com declividades acima de 10%, principalmente, e em áreas como solos muito arenosos, profundos, homogêneos, permeáveis e cobertos por pastagens ou vegetação ciliar. As técnicas de interpretação e restituição aerofotogramétricas digitais se mostraram muito superiores às analógicas, embora o processo digital tenha se mostrado mais moroso que o analógico. As técnicas digitais permitiram a correção de grande parte das distorções geométricas das fotos, facilitando, dessa forma, as medidas das ravinas e voçorocas.
This study aimed to make an inventory of the forms of linear erosion in the high basin of the river Araquá, municipality of San Pedro and Charqueada / SP, based on cartographic and aerophotogrametric techniques in analog and digital environment. The survey was conducted in 2 different scales of approach: 1:50.000 (semi-detailed) and 1:15.000 (detailed). In the semi-detailed scale, it was produced a hypsometric chart, a slope chart and a morphological map, where the forms of linear erosion were represented. These products, with the informations about soils, lithology and land use, led to the morphopedologic map. Based on this map, was choose the sub-basin of the Querosene stream for the study on detailed scale. In the sub-basin of the Querosene stream were produced hypsometric and slope charts, morphologic, soils, land use and linear erosion maps. The survey of land use and linear erosion was based on photographs of 4 different periods, 1962 (1:25.000), 1978 (1:35.000), 1995 (1:25.000) and 2006 (1:30.000). This diagnosis made possible to create a susceptibility erosion chart and to correlate forms of linear erosion with the characteristics of the physical environment as well as assessments of the temporal evolution of the erosion. The results showed that the area affected by furrows decreased 38,18% from 1962 until 2009. In contrast, the areas with grazing tracks made by cows increased 137%. In the same period, the number of ravines increased 87,5% and gullies about 300%. The data also showed that the ravines and gullies are preferably in hollow forms, >10% slopes, mainly in areas of very sandy, deep, homogeneous and permeable soils, which are covered by grassland or ciliary vegetation. The techniques of digital aerophotogrametric interpretation and restitution showed far superior to analog, but the digital process is slowest than the analog. The digital techniques allowed the correction of most of the geometric distortions of the photos, facilitating, thus, the measures of ravines and gullies.

[Truncated abstract] Landforms rehabilitated after bauxite mining can be vulnerable to soil loss by water erosion processes. On most rehabilitated sites, management controls such as deep ripping, contour mounding and landscaped sub-catchments limit erosion. Despite these measures, severe gully erosion that is anecdotally associated with steep slopes can damage rehabilitated areas and affect downstream drinking water resources. A review of erosion dynamics reveals that gullies develop episodically and in a non-linear manner. They often initiated as a near surface process and are influenced by natural climatic drivers. Despite this, local site characteristics including soil and landform can predispose an area to gully erosion. Moreover, erosion models, becoming more-widely utilized within the mining industry, may provide useful tools with which to measure, analyse, and manage gully erosion. One of these models, SIBERIA was tested to determine its suitability for application a tool to help manage erosion risk. We first surveyed 26 eroding and erosion-prone rehabilitated hillslopes to determine the common form and setting for gully erosion on these rehabilitated bauxite mines. A conceptual model was developed to include and explore the interplay between the common causes of the gullies surveyed. The conceptual model accounts for slope steepness but suggests that additionally, certain triggers and threshold effects operating under different site conditions are as influential (or even more influential) than slope steepness as determinants of gully erosion occurrence and severity. ... Soil properties and soil erodibility had some subtle influence on landform stability and erosion risk. The most-erodible media occurred where either: mine floor material was mixed with topsoil/ overburden; and/or the topsoil/overburden layer was thin or its coverage is patchy resulting in slaking subsoil, hardsetting soil and surface crusts. When erodible surface media were combined with steeper (>8[degrees]) or longer (>50 m) slopes or with any major erosion trigger, rill and gully development was greatly intensified. The SIBERIA simulation model was calibrated and its simulated outputs were compared to known locations of gully erosion on a steep, rehabilitated pit from the Willowdale mine. At a resolution of one metre, SIBERIA was able to simulate the approximate dimensions of gullies. However, SIBERIA could not simulate the exact location of individual gully headcuts. Additionally, SIBERA was able to simulate the effect of different microtopographic surface treatments but this was only achieved by increasing the grid resolution to 25 cm and reducing the size of the area simulated due to model constraints. Locations of gully headcuts were overlain onto a grid-based, Digital Elevation Model (DEM) using a Geographic Information System (GIS). The spatial distribution of gully headcut locations was compared to DEM derivatives such as slope and flow accumulation. Positive, and predictive relationships allow between the steepness of the slope of the pre-mining landform and the cell count of the area contributing to flow (catchment), as determined by GIS, may allow a mine scale indication of erosion risk using simple GIS desktop analysis.

This thesis provides an alternative method to for mapping soil erosion. The method is conducted in a small study area of 40 km2 in the Sorbas Basin, Almería province, Southeast Spain. Soil erosion is one of the most destructive land degradation processes and can often lead to serious environmental problems. It is important to implement appropriate management strategies to meet these challenges at a range of scales. However, prior knowledge of erosion processes and the extent to which they operate spatially is often limited and, traditional methods of soil erosion mapping are often time and labour intensive. This thesis explores the use of two Artificial Intelligence (AI) techniques for soil erosion mapping; Artificial Neural Networks (ANNs) and Decision Tree Classifiers (DTCs). The opportunities for employing such methods relate in part to their non-linear capabilities, their ability to learn in an inductive manner and incorporate multi¬source data sets. AI training and test data were collected from 520 individually sampled locations within the study area. At each site the dependent variable erosion was estimated, as were a range of independent variables through field study. Two Digital Elevation Models were developed. Laboratory analysis was also undertaken to explore the physico-chemical processes relating to soil dispersion and to determine the applicability of a soil sodicity meter developed by the Co-operative Research Centre for Soil and Land Management in Adelaide, Australia. Results demonstrate that classification accuracy.and overall performance is strongly dependent on the independent and dependent variables used, with the more expensive field collected data providing improved variables to those extracted from the Digital Elevation Models. Discriminant Analysis (DA) classifications were also employed to provide a linear comparison to the AI techniques, and performed comparably well. In the Artificial Neural Network classifications the composition of the training set was seen to exert significant bias, leading to poor performance and often misleading results. Laboratory analysis highlights the complex physico-chemical relationships associated with soil dispersion. The findings also indicate that no discernible relationship exists between the sodicity meter and standard laboratory procedures employed to measure the sodic properties of a soil. The thesis demonstrates the potential for employing these methods for erosion risk analysis and the ability of inductive approaches to formulate rules that may enhance current levels of understanding associated with soil erosion processes. Mapped outputs produced by these methods may prove valuable in the management of landscapes susceptible to soil erosion.

Soil erosion is a major global environmental problem that is increasing year by year in Turkey. Preventing soil erosion requires political, economic and technical actions
before these actions we must learn properties and behaviors of our soil resources. The aims of this study are to estimate annual soil loss rates of a watershed with integrated models within GIS framework and to map the soil erosion risk for a complex terrain. In this study, annual soil loss rates are estimated using the Universal Soil Loss Equation (USLE) that has been used for five decades all over the world. The main problem in estimating the soil loss rate is determining suitable slope length parameters of USLE for complex terrains in grid based approaches. Different algorithms are evaluated for calculating slope length parameters of the study area namely Kocadere Creek Watershed, which can be considered as a complex terrain. Hickey&
#8217
s algorithm gives more reliable topographic factor values than Mitasova&
#8217
s and Moore&
#8217
s. Satellite image driven cover and management parameter (C) determination is performed by scaling NDVI values to approximate C values by using European Soil Bureau&
#8217
s formula. After the estimation of annual soil loss rates, watershed is mapped into three different erosion risk classes (low, moderate, high) by using two different classification approaches: boolean and fuzzy classifications. Fuzzy classifications are based on (I) only topographic factor and, (II) both topographic and C factors of USLE. By comparing three different classified risk maps, it is found that! in the study area topography dominates erosion process on bare soils and areas having sparse vegetation.

Climate change and warming have been linked to enhanced coastal erosion in the arctic. Specifically, permafrost is believed to be thawing at greater rates, and wave dynamics are expected to increase in intensity. As a result, thermokarst activity, which includes the occurrence of retrogressive thaw slumps, will be more frequent along arctic coasts.
The availability of airborne and spaceborne imagery in the arctic over the last fifty years has made possible the temporal analysis of permafrost and ground ice-related erosion. The objectives of this thesis are (1) the creation of a large scale database for horizontal coastal retreat on Herschel Island for the 1952-2000 timespan, (2) the investigation of retrogressive thaw slump activity over the same period and its relation to coastal erosion, and (3) the elaboration of stereophotogrammetric techniques to investigate retrogressive thaw slump activity volumetrically. Herschel Island, located on the northern coast of the Yukon Territory, was chosen as the study site for this research, because of the widespread presence of retrogressive thaw slumps and the lack of data for coastal erosion during the last fifty years.
Photogrammetric tools were used to create orthorectified and stereo-images of the Island for the years 1952, 1970, 2000 and 2004 from airphoto archives and Ikonos (1 m resolution) imagery. Coastal erosion was found to be stable or declining on Herschel Island except in the vicinity of retrogressive thaw slumps. In addition, retrogressive thaw slumps were identified on the imagery and observed to have increased in frequency for the 1952-2000 period.
Stereophotogrammetric analysis of two retrogressive thaw slumps showed that eroded sediment volumes from these landforms are considerable and should be included in future assessments of sediment release from arctic coasts to the oceanic shelves.

Soil degradation is defined as a decrease in soil quality, which is caused by non sustainable soil management. When the soil is losing its functionality is directly related with decreasing soil quality. This PhD proposes a scheme of intrinsic soil indicators for determining soil quality. This scheme includes three different sets of soil quality indicators derived from basic soil use criteria. Such criteria is based upon indicator availability, suitability and usefulness. These indicators are grouped according to three different soil threats; declining organic matter, desertification and soil salinity. These indicators were chosen under a European framework (COM (2002) 179 final) and by natural processes. With respect to this framework, these indicators should be interpretable in the context of soil quality, whilst also providing an auditable pathway through which soil management decisions can be made. The methods selected showed helpful results determining soil quality being well selected for the use of soil indicators. EM measurements provide relevant information on within-field variability of soil salinity. SOC distribution is important to be calculated in space and in depth. The MEDALUS and RUSLE models can assess the extent, intensity and severity of desertification processes in the target area.
La degradació dels sòls es defineix com la disminució de la seva qualitat causada per un mal ús per part de l’espècie humana, o bé per causes generals. Així doncs, la pèrdua de funcionalitat del sòl està lligada a la disminució de la seva qualitat. En aquesta tesi s’ha estudiat el comportament d’indicadors de qualitat del sòl escollits sota un marc polític de la Unió Europea (COM(2002)). En concret, s’han estudiat indicadors relacionats amb tres amenaces/qualitat del sòl, contingut de matèria orgànica, grau de desertificació de les terres i estat de salinitat dels sòls, amb l’objectiu de validar la seva funcionalitat per qualificar el sòl. Els estudis s’han portat a terme en dues àrees ben diferenciades de Catalunya, al marge esquerra del Delta de l’Ebre i a una zona concreta del municipi de Canalda-Odén (Solsona) a la Catalunya central. Els mètodes seleccionats han mostrat donar bons resultats en la determinació de la qualitat del sòl, sent ben seleccionats com indicadors de qualitat del sòl. L’ús de l’electromagnètic sensor proporciona bona informació per a l’estudi de la variabilitat de la salinitat del sòl. La distribució carboni orgànic del sòl és important calcular-lo per veure com canvia tan en l'espai com en profunditat. Els models MEDALUS i RUSLE han mostrat avalar l'abast, la intensitat i la gravetat dels processos de desertificació a la zona d’estudi.
La degradación de los suelos se define como la disminución de su calidad del suelo causada por un mal uso por parte de la especie humana, o bien por causas generales. Así pues, la pérdida de la funcionalidad del suelo está ligada a la disminución de calidad de éste. En la presente tesis se ha estudiado el comportamiento de indicadores de calidad del suelo escogidos bajo un marco político de la Unión Europea (COM(2002)). En concreto, se han estudiado indicadores relacionados con tres amenazas del suelo, contenido de materia orgánica, grado de desertificación de las tierras y estado de salinidad de los suelos, con el objetivo de validar su funcionalidad para cualificar el suelo. Los estudios se han realizado en 2 áreas bien diferenciadas de Catalunya, en el margen izquierdo del Delta del Ebro y una zona concreta del municipio de Canalda-Odén (Solsona) en la Catalunya central. Los métodos seleccionados han mostrado dar buenos resultados en la determinación de la calidad del suelo, siendo bien seleccionados como indicadores de calidad del suelo. El uso del sensor electromagnético proporciona buena información para el estudio de la variabilidad de la salinidad del suelo. La distribución carbono orgánico del suelo es importante calcularlo para ver cómo cambia tanto en el espacio como en profundidad. Los modelos MEDALUS y RUSLE han mostrado avalar el alcance, la intensidad y la gravedad de los procesos de desertificación en la zona de estudio.

Este trabalho objetivou analisar a suscetibilidade à erosão linear da região do Médio Rio Grande (MG), que abrange uma área de 9794,12 km², através de documentos cartográficos interpretativos. Utilizando técnicas de geoprocessamento e sensoriamento remoto associadas a levantamentos de campo e ensaios de laboratório, foram produzidos os seguintes documentos cartográficos: Carta de Declividade, Mapa de Landforms, Mapa de Materiais Inconsolidados e Inventário de Feições Erosivas. O produto final do trabalho, a Carta de Suscetibilidade à Erosão em escala 1:100.000, foi elaborada utilizando informações referentes ao substrato rochoso, formas do terreno, materiais inconsolidados e declividade. Cada documento cartográfico utilizado foi analisado de forma individual, para observar a potencialidade de cada um de seus atributos internos (ou classes) em desenvolver processos erosivos, assim, foram atribuídos pesos através do Processo Analítico Hierárquico (AHP). A Carta de Suscetibilidade à Erosão obtida conseguiu retratar bem a suscetibilidade da área, pois dos 78 processos erosivos de grande porte (boçorocas), identificados no inventário, em torno de 80% estão situados nas classes de alta e muito alta suscetibilidade à erosão. Portanto, esta Carta indica quais são as áreas em que se deve ter um controle mais rígido do uso e ocupação do solo para prevenir o desencadeamento de processos erosivos de grande porte, ou seja, auxilia no planejamento ambiental e na definição de medidas a serem tomadas.
This study aimed to analyze the susceptibility to linear erosion of the region of the Middle Rio Grande (Minas Gerais - Brazil) that covers an area of 9794.12 km², through interpretive cartographic documents. Using geoprocessing techniques and remote sensing associated with field surveys and laboratory tests, the following cartographic documents were produced: Chart of Slope, Landforms Map, Map of Unconsolidated Material and Inventory of Erosive Features. The final product of this work is the Chart of Erosion Susceptibility in scale 1:100,000. It was prepared using information relating to the bedrock, forms of terrain, unconsolidated materials and slope. Each cartographic document used was analyzed individually in order to observe the potential of each of its internal attributes (or classes) to develop erosive processes, thus were assigned weights using the Analytic Hierarchy Process (AHP). The Chart of Erosion Susceptibility obtained could well portray the susceptibility of the area because analyzing a total of 78 large erosion processes (gully erosion) identified in the inventory, about 80% are located in the classes of high and very high susceptibility to erosion. Therefore, this Chart indicates which areas in which to have a tighter control of the use and occupation of land to prevent large erosion triggering, ie assists in environmental planning and defining actions to be taken.

Gun barrels are an important component in advanced defence systems. The gun barrels are used for direct and indirect fire and the material of the gun barrel is exposed to great strains and high temperatures. This sets high demands on the material of the gun barrel. During firing the gun barrel can be damaged. The first damage in gun barrels is the wear of the rifling followed by fatigue. When fatigue occurs cracks can propagate downwards into the bore and could result in catastrophic failure. Therefore investigation regarding the wear, the mechanisms and the underlying factors causing the damage will be performed. How and where the wear in gun barrels occur and also which wear mechanisms causing the wear. Wear in gun barrels involves extreme conditions during firing such as high gas pressure and high temperature from the burning propellant. This thesis work aims to understand how and why wear and damaging mechanisms in gun barrels occurs. Moreover how other ballistic factors influences have on the wear. The wear in gun barrels is caused by erosion from the combustion gases or/and sliding wear caused by the high-speed projectile. The phenomena of wear are complicated and factors like deformation state, types of wear, environment and process are interrelated with each other. These give the rise of wear. In this thesis, samples from three gun barrels were analysed. A new unworn gun barrel, a medium worn gun barrel and a severely worn gun barrel. From the used gun barrels 4 critical positions were identified, then samples from both surface and cross-section were obtained from the gun barrels. The surface and cross-section were analysed using different methods including optical light microscopy and scanning electron microscopy to characterise the surface damage and wear mechanisms. The results from the investigation revealed the dominating wear mechanism to be thermal and chemical erosion at the positions closest to the combustion chamber with heat checks as its signature feature. The heat checks are associated with fatigue cracks developed at the surface and during thermo-mechanical loading, allows it to propagate down into the surface. For both samples at position 2, after the start of the rifling, adhesive wear was obtained too. The adhesive wear was induced by material pick-up from the driving band of the projectile during sliding. In other meaning, the material is transferred from the counter-face to the bore surface. The severely worn gun barrel had been subjected to sliding wear at the muzzle end compared to the medium worn gun barrel which hadn’t experience the same wear rate at the same position. The analysis of the cross-section examination revealed information about the structure and condition of the material. To obtain more information about mechanical properties, a hardness test was performed. The hardness test revealed a hard but brittle surface which can be sheared by the frictional force caused by the sliding projectile. The analysis of the gun barrels revealed information about wear mechanisms and damages in medium and severely worn gun barrels. The detected wear mechanism was thermal erosion, chemical erosion, mechanical erosion and sliding wear.

This Thesis presents a spatially and temporally explicit and novel framework to identify, quantify and map soil erosion prevention aimed at establishing the links between the provision of ecosystem services and policy implementation and land management. Recent studies show that introducing the ecosystem service concept into policy and decision-making requires spatially explicit information on the state and trends of ecosystems and their services. Current spatially explicit approaches often fail to make a distinction between the actual ecosystem service provision and the underlying ecosystem capacity to provide a specific service. Here we propose and test a spatially and temporally explicit ecosystem service assessment framework to assess the provision of the soil erosion prevention service based on the combination of biogeographic, ecological and land management factors. This ecosystem service is of particular importance in Mediterranean areas dominated by silvo-pastoral systems, which are prone to soil degradation, often caused by a wide variety of social and policy drivers. The proposed framework estimates the service provision based on the spatial and temporal arrangement of potential impacts and its relation to the actual and potential ecosystem service provision, allowing to identify thresholds of management change and vulnerability hotspots. Results show that it is not possible to directly relate the capacity for ecosystem service provision with the actual ecosystem service provision. In the particular case of regulating services, establishing this link in mapping and assessment exercises will result in incorrect evaluations due to the spatial and temporal mismatch between these two indicators. The results also show the importance and impacts of land management and policy implementation in the provision of soil erosion prevention in Mediterranean land use systems. Overall, the combination of the different aspects of this Thesis provides a comprehensive overview of the potential applications of the proposed ecosystem service indicators to quantify and map soil erosion prevention and to support monitor and decision-making exercises at both land management and policy levels; Um quadro de análise espacialmente explícito para a avaliação da vulnerabilidade da prevenção de erosão hídrica: contribuições para o mapeamento e gestão de serviços de ecossistema em usos do solo mediterrânicos RESUMO: Esta Tese apresenta um novo quadro de análise espacial e temporalmente explícito para identificar, quantificar e mapear o serviço de ecossistema de prevenção de erosão do solo com o objectivo de estabelecer relações entre a provisão de serviços de ecossistema e a implementação de políticas e a gestão da terra. Estudos recentes mostram que a introdução do conceito de serviços de ecossistema esfera política e na tomada de decisão requer informação espacialmente explícita sobre o estado e as tendências dos ecossistemas e seus serviços. Atualmente as abordagens espacialmente explícitas muitas vezes não conseguem capturar a distinção entre a provisão de serviços de ecossistema efetiva e da capacidade do ecossistema para fornecer um serviço específico. Aqui propomos e testamos um quadro de análise, espacial e temporalmente explícito, para avaliar a provisão do serviço de ecossistema de prevenção de erosão do solo com base na combinação de fatores biogeográficos, ecológicos e de gestão da terra. Este serviço de ecossistema é de particular importância nas zonas mediterrânicas dominadas por sistemas silvo-pastoris, que são propensas a degradação do solo, muitas vezes causada por uma grande variedade de fatores sociais e políticas. O quadro de análise proposto estima a provisão de serviços de ecossistema com base no arranjo espacial e temporal do impacte potencial e sua relação com a efetiva e potencial provisão de serviços de ecossistema, permitindo identificar limiares de mudança de gestão e hotspots de vulnerabilidade. Os resultados mostram que não é possível relacionar diretamente a capacidade de provisão de serviços de ecossistema com a efetiva provisão de serviços de ecossistema. No caso particular dos serviços de regulação, estabelecer esta relação em exercícios de mapeamento e avaliação irá necessariamente resultar em avaliações incorretas devido ao desencontro espacial e temporal entre esses dois indicadores. Os resultados também mostram a importância e os impactes resultantes da gestão da terra e da implementação de políticas na prevenção da erosão do solo em sistemas de uso da terra Mediterrânicos. De uma forma geral, a combinação dos diferentes aspectos desta Tese fornece uma visão abrangente das potenciais aplicações dos indicadores de serviços de ecossistema propostos para quantificar e mapear a prevenção da erosão do solo e apoiar exercícios de monitorização e de tomada de decisão, tanto ao nível da gestão da terra como da definição de políticas.

Este trabalho consiste em um mapeamento geotécnico da bacia do córrego da Barra, localizada no município São Pedro, no Estado de São Paulo, apresentando uma área aproximada de 56,5 \'KM POT.2\'. Para realização deste trabalho, efetuou-se um levantamento dos trabalhos anteriores realizados na área, fotointerpretação, e trabalhos de campo. Foram elaborados documentos cartográficos na escala 1:10.000: mapa de substrato rochoso, mapa de materiais inconsolidados, declividade e inventário das feições erosivas. Utilizou-se o penetrômetro de impacto (modelo IAA/Planalsucar-Stolf) para a determinação da resistência a penetração, entre as profundidades de 10 a 60 cm. Em seguida estes resultados foram correlacionados com a ocorrência de erosões na bacia, determinando assim qual o solo e qual o tipo de uso que favorecem a ocorrência e a evolução dos processos erosivos.
An engineering geological mapping was carried out in the basin of stream Barra, located in the São Pedro municipality in the state of São Paulo-Brasil. The area of 56,5 \'KM POT.2\' were mapped based on information of previous works, photointerpretation, and field works. The following cartographic documents were performed in 1:10.000 scale: rock substratum, unconsolidated materials, slope and inventory of erosive features. The penetrometer for soil (IAA/Planalsucar-Stolf) was utilized to determine the penetration resistance of the soil from 10 to 60 cm of depth. Soon afterwards the results of penetration resistance, soil type, use and occupation were correlated to establish the main factors in the erosion process.

Thesis (MSc (Earth Sciences))--Stellenbosch University, 2008.
This study aims to provide a practical tool for the prediction and management of dust generated by the activities of an opencast mining operation. The study was conducted on opencast gypsum mines in the semi-arid environment of the Bushmanland, 90 km north of Loeriesfontein in the Northern Cape Province from April 2000 to October 2007. The vertical and horizontal components of wind transported sediment were sampled and a dust settling model was designed to predict the settling pattern of dust generated by opencast mining operations. The model was applied to soil samples collected from an area surrounding a mine. The influence sphere of the mining operation was predicted by the application of the model and then mapped. Once the influence sphere is mapped, the dust influence can be managed with the aid of an onsite weather station. By further applying the predictions based on climatic data, the influence sphere can be modelled. The model is not only applicable to the planning phase of an opencast mine to plan the position of dust sensitive areas like the living quarters, office buildings and workshops etc., but also to indicate the historical impact that a mining operation had once a quarry on an active mine is worked out and rehabilitated or a mine is closed. The model application can also aid with the explanation and visual or graphic representation of the predicted impact of planned mining operations on communities or neighbouring activities to them and thus avoid later penalties.

Newly available industry well data and seismic attribute analysis reveal that late Ordovician-early Devonian Hunton Group strata are more widespread (i.e., not removed by mid-Devonian erosion) in the central and southern portions of the Arkoma Basin in eastern Oklahoma than previously thought. This study demonstrates the value of applying seismic attribute analysis to problems of quantifying and mapping stratigraphic features caused by erosions and/or karstification. Well and seismic isochron data in the Red Oak petroleum field for the Viola-Woodford interval (the units that lie stratigraphically beneath and above, respectively, the Huton Group) show isolated ~40-m thick lenses of Hunton rocks, on average measuring 3 km in diameter, with a surrounding halo of karsted rock. This distribution can be explained in two different ways: 1) Hunton occurrences could represent isolated erosional remnants reflecting incomplete removal of the Hunton Group during Middle Devonian time (pre-Woodford unconformity) or 2) due to karsting and collapse of stratigraphically lower units (Viola or Bromide carbonates), lenses of Hunton rocks would have sagged into sinkholes where they were preserved beneath regional base level. Using formation tops from a well data set correlated with attribute and structure maps from a proprietary 3-D seismic data set, we identify three seismic characteristics in the middle Paleozoic interval that correlate well with: 1) absent Hunton seismic markers, indicating that Hunton rocks were completely removed, 2) the Hunton contacts, indicating where a seismically visible section of Hunton rocks remains, 3) absent Hunton but with a thin horizon included within lower carbonate strata that is interpreted to be an incipient karst zone, which is consistently adjacent to areas containing Hunton rocks. The base of the Sylvan Shale and the top of the Woodford Shale, the respective lower and upper adjoining units, form significant chronostratigraphic surfaces. As such, anomalous thicknesses of these units are depositionally related; thick Woodford sections often correlate to thin or absent Hunton rocks, possibly indicating back-filled pre-Woodford channels eroded into or through the Hunton Group. Conversely, when there is little or no Woodford thickening over Hunton lenses and when adjacent areas show thinning and partially karsted Viola rocks, we propose that karstic collapse of Viola strata was responsible for the Hunton rocks preservation. A combination of these models may be necessary to account for areas where we see thinning both in the Woodford and Viola, suggesting that a Hunton lens is structurally lowered due to karsting, but due to its erosionally resistive nature, the lens forms a depositional high, causing the Woodford to thin over it. The 3-D approach is absolutely necessary to reveal the subtle waveform details that illustrate the karstic and erosional processes involved in the preservation of the Hunton wedges. These findings were interpolated, constrained by well data, over the entire Oklahoma portion of the Arkoma basin in order to produce a new Hunton isopach map and 20 separate cross-sections (two shown herein). These show a broad linear region of absent Hunton. Eustatic sea levels rose throughout the middle and late Devonian, so this large area of eroded Hunton is interpreted as a post-Hunton, pre-Woodford structural uplift. Other Hunton wedges, similar in size and extant to that seismically imaged in this study, were also found in the well data. The karstic collapse of the Viola and subsequent preservation of Hunton rocks occurred on both limbs of the arch.

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Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico
This work presents a study on the environmental vulnerability of the coastal region of Pititinga, Rio do Fogo/RN. The coastal erosion of Pititinga beach was analyzed and considerated as one more process that produces environmental vulnerability in the area of study, taking into account its human and natural environment and establishing the relation between them, to understand the arrangement that produced its spatial configuration. The natural environment was expressed by thematics maps with geology, geomorphology, vegetation and soil themes, while the human environment was expressed by the use and occupation of the soil map. The coastal erosion was put in an erosion vulnerability map. The methodological procedure to generate the thematics maps, vulnerability maps and of the erosion coastal involved the bibliographic research, field visits with check-list form fill, collect and analysis of sediment sample, photo-interpretation techniques, integration of the information in a database, data store and spatial analysis in a Geographic Information System (GIS) ambient. The natural vulnerability map shows a predominancy of environments with low (29,6%) or medium (42,4%) vulnerability, pointed the frontal and mobile dune as the areas with the highest vulnerability. The environmental vulnerability map, presents a predominancy of environments with low vulnerability (53,8%), with the high vulnerability concentrated on Pititinga community. The coastal erosion vulnerability presented distinct behaviors on three sections among the coastal line according each one characteristics. Where there are frontal and transgressive dunes, vulnerability are, generally, medium or low, respectively, and in the absence of them, as what occurs in Pititinga community, the vulnerability is predominately very high
Este trabalho apresenta um estudo sobre a Vulnerabilidade Ambiental da regi?o costeira de Pititinga, Rio do Fogo/RN. A eros?o costeira da praia de Pititinga foi analisada e considerada como mais um processo que gera vulnerabilidade ambiental na ?rea de estudo, considerando seu meio natural e humano e estabelecendo a rela??o entre eles, para compreender os arranjos que produziram a sua configura??o espacial. O meio natural foi expresso por meio de mapas tem?ticos envolvendo os temas geologia, geomorfologia, vegeta??o e pedologia, enquanto que o meio antr?pico foi expresso pelo mapa de uso e ocupa??o do solo. A eros?o costeira foi cartografada em um mapa de vulnerabilidade ? eros?o. O procedimento metodol?gico para gerar os mapas tem?ticos, os mapas de vulnerabilidade natural e ambiental e da eros?o costeira envolveu o levantamento bibliogr?fico, visitas a campo com preenchimento de check-list, coleta e an?lise de amostras de sedimentos, t?cnicas de fotointerpreta??o, integra??o das informa??es em uma base de dados e armazenamento e an?lise espacial em um ambiente de Sistema de Informa??es Geogr?ficas (SIG). O mapa de vulnerabilidade natural apontou para um predom?nio de ambientes com vulnerabilidade baixa (29,6%) e m?dia (42,4%), destacando as dunas frontais e m?veis com as ?reas de maior vulnerabilidade. J? o mapa de vulnerabilidade ambiental, apresenta um predom?nio de ambientes com vulnerabilidade baixa (53,8%), estando a vulnerabilidade alta concentrada sobre a vila de Pititinga. A vulnerabilidade ? eros?o costeira apresentou comportamentos distintos em tr?s trechos ao longo da linha de costa de acordo com as caracter?sticas de cada um. Quando ocorrem dunas frontais e transgressivas as susceptibilidades s?o, em geral, m?dia e baixa, respectivamente, e quando da aus?ncia destas, como ocorre vila de Pititinga, a vulnerabilidade ? predominantemente muito alta

Este trabalho envolve o estudo dos solos de cerrado, formação savânica existente no Brasil, da borda ocidental do Planalto Central Brasileiro, baseado no uso e ocupação e suas conseqüências ao meio ambiente, na Bacia Hidrográfica do Ribeirão Ponte de Pedra, que drena os municípios de Rondonópolis, Pedra Preta e Itiquira, sul do Estado de Mato Grosso, região Centro Oeste do Brasil. Objetivou-se identificar os atributos do meio físico através de mapeamento geotécnico, tais como, substrato rochoso, landforms, materiais inconsolidados, topografia, rede de drenagem e outros de natureza antrópica que influenciam na mudança das características ambientais desse importante ecossistema rico em biodiversidade, utilizando como base a metodologia proposta pela Escola de Engenharia de São Carlos (USP), da técnica de avaliação de terreno, tendo como ferramenta, diversos programas de geoprocessamento para geração de mapas e cartas, dando subsídios ao estudo, avaliação e análise dos graus de susceptibilidade à erosão de seus terrenos
This paper involves the study of the “cerrado” soils, a savannah-like formation found in Brazil, at the Western border of the Brazilian Central Plain, based on its use and occupation and the impacts thereof on the environment, in the Water Basin of Ribeirão Ponte de Pedra, which drains the municipalities of Rondonópolis, Pedra Preta and Itiquira, in the South of the State of Mato Grosso, in the Center-West region of Brazil. The purpose of this paper was to identify the physical characteristics through geotechnical mapping, such as, the rock substrate, landforms, unconsolidated materials, topography, the drainage network and other anthropic features that influence changes in the environmental characteristics of this important ecosystem, rich in biodiversity, based on the methodology proposed by Escola de Engenharia de São Carlos (USP) and on the Land Evaluation Technique, by means of various geoprocessing models, to produce maps and charts, to subsidize the study, evaluation and examination of the susceptibility levels of the soils to erosion

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
No atual momento histórico, diante das transformações aceleradas das paisagens, em que as dinâmicas da sociedade se interpenetram e, muitas vezes, se sobressaem às dinâmicas da natureza, a questão ambiental assume importância em vários campos do conhecimento, sobretudo, na Geografia. Em meio aos diversos trabalhos desenvolvidos no âmbito geográfico e ambiental, tem-se a erosão como um dos assuntos mais enfatizados. Neste contexto, o objetivo geral da tese foi analisar os principais elementos que influenciam na vulnerabilidade ambiental aos processos erosivos lineares (sulcos, ravinas e voçorocas) de parte dos municípios de Marabá Paulista-SP e Presidente Epitácio-SP. Sob a perspectiva teórico-metodológica do pensamento da complexidade, foram caracterizados os aspectos do relevo, declividade, solos, substrato rochoso, cobertura vegetal, curvatura da superfície e uso da terra, além da elaboração de documentos cartográficos em ambiente de Sistemas de Informação Geográfica, em especial, o mapa de vulnerabilidade ambiental aos processos erosivos lineares. Em virtude das possibilidades de integração dos dados e atribuição de pesos, o referido mapa foi realizado a partir da lógica fuzzy, especificamente, da Técnica do Processo Analítico Hierárquico (AHP), a qual proporcionou o mapeamento de maneira classificada: baixa (0.32%), média (65.15%), alta (34.45%) e muito alta vulnerabilidade (0.08%). A baixa vulnerabilidade está elencada às matas ciliares remanescentes. A média vulnerabilidade se localiza nos topos das colinas com declividades inferiores a 5%. O uso da terra predominante é a pastagem e os solos são, em sua maioria, desenvolvidos e arenosos. A alta vulnerabilidade está, principalmente, nas vertentes convexas e retilíneas, em que as inclinações podem alcançar 15%. A pastagem prevalece, todavia, verificou-se a expansão do cultivo de cana de açúcar e do solo exposto para seu consecutivo plantio. A muito alta vulnerabilidade apresenta-se nas vertentes côncavas, cuja curvatura favorece a convergência das águas pluviais e, portanto, o fluxo linear. Tal evento se intensifica perante às declividades acentuadas – superiores a 20% para a região. Combinado a estes atributos, sobre solos rasos tem-se o pastoreio intensivo do gado, o qual acelera a compactação do solo e acarreta a erosão, sendo uma das formas de degradação mais recorrente no Extremo Oeste Paulista. Assim, o presente estudo pode contribuir no sentido de orientar a implantação de medidas preventivas e corretivas de controle à erosão por intermédio do planejamento ambiental.
In the current historical moment, given the accelerated changes in landscapes, in which the dynamics of society interpenetrate and, often, exceed the dynamics of nature, the environmental issue assumes importance in several fields of knowledge, especially, Geography. Among the diverse assignments developed in geographical and environmental contexts, erosion is one of the most commonly emphasized subjects. Therefore, this thesis aimed to analyze the main elements that influence environmental vulnerability to linear erosive processes (rills, ravines and gullies) in parts of Marabá Paulista-SP and Presidente Epitácio-SP. From the theoretical-methodological perspective of thought complexity, the relief, slope plans, soils, bedrocks, vegetation, surface curvature and land use aspects were characterized, in addition to the elaboration of cartographic documents using the Geographic Information System, in particular, the map of environmental vulnerability to linear erosive processes. Due to the possibilities of integrating data and assigning weights, the map was performed based on fuzzy sets, specifically, the Analytical Hierarchy Process (AHP), which provided classified mapping: low (0.32%), medium (65.15%), high (34.45%) and very high vulnerability (0.08%). The low vulnerability is identified in the reminiscent cilliary forests. The medium vulnerability is located on the hilltops with slopes of less than 5%. The land use is predominantly for pasture and soils are for the most part developed and sandy. The high vulnerability is primarily the convex and rectilinear aspects, where the slopes can reach 15%. On the prevailing pasture, however, the expansion of the sugar cane crop was found and soil exposed to its successive planting. The very high vulnerability is present in the concave slopes, whose curvature favors the convergence of rainwater and thus, linear flow. This event is intensified towards the steep slopes – more than 20% of the region. Combined with these attributes, on shallow soils there is intensive grazing of livestock, which accelerates soil compaction and leads to erosion, one of the most recurrent means of degradation in the Far West of São Paulo. Thus, the present study may contribute to guiding the management of preventive and corrective measures to control erosion through environmental planning.

O presente trabalho consistiu na identificação de uma série de atributos do meio físico com o objetivo de gerar uma carta de susceptibilidade à erosão das bacias hidrográficas dos rios Cubatão e Araraquara em escala 1:50.000, ambas pertencentes à bacia do Rio Pardo. Os atributos do meio físico analisados foram o substrato rochoso, os materiais inconsolidados, declividade e uso e ocupação da área. A carta de susceptibilidade à erosão visa identificar áreas com diferentes graus de vulnerabilidade frente ao processo erosivo, de forma a facilitar o planejamento do uso e ocupação daquela região. Este estudo foi realizado seguindo as bases conceituais e metodológicas da cartografia geotécnica tradicional. Nesta pesquisa, foram utilizados sistemas de informação geográfica, tanto para análise de imagens de satélite para um fim específico, quanto para o tratamento dos dados do meio físico obtidos ao longo das etapas do trabalho. Procurou-se também compreender melhor a propriedade chamada de erodibilidade e identificar quais atributos relacionados com o materiais inconsolidados que mais contribuem para a predisponência do mesmo em ser erodido.
In this present work many environmental attributes were identified, in order to create a soil erosion susceptibility chart (1:50.000 scale) for the Cubatão and Araraquara hydrographic basin, which in turn, are part of the greater Pardo river basin. These attributes were bedrock classification, unconsolidated materials, slope and land use. The soil erosion susceptibility chart was meant to help the land use management of that particular region by identifying areas with different soil erosion vulnerability. This study was leaded following conceptual and methodological bases from the traditional engineering geological mapping approach. Geographical information system (GIS) were applied to analyze satellite images for a specific utilization, as well as for dealing with the environmental data, obtained along all the work stages. It was intended also to provide a better understanding of the property called erodibility and to identify which of the unconsolidated material attributes really contributes to its erosion.

Le bassin supérieur de l’oued Djemaa qui fait partie de la montagne du Djurdjura est affecté par une importante morphogenèse. Les mouvements de terrain présentent une grande variété dans le secteur d’étude et jouent un rôle prépondérant dans l’évolution des versants. L’étude géomophologique détaillée, une enquête auprès des populations locales, des analyses géotechniques et l’analyse sédimentologique des formations déplacées nous ont permis de faire une typologie des mouvements de terrain et de dégager les facteurs de leur développement et de leur localisation. Les fortes précipitations d’hiver et de printemps sont à l’origine de tous les mouvements de terrain et des ravinements, mais l’exposition et la lithologie permettent de comprendre les formes différentes rencontrées sur les adrets et sur les ubacs. Les activités humaines jouent un rôle croissant dans l’accélération de la morphogenèse. Dans cette étude, un système d’Information Géographique a été utilisé pour produire les cartes des risques de dégradation du milieu qui sont des outils pour la planification et la gestion de l’utilisation du sol dans le bassin supérieur de l’oued Djemaa. Il permet de croiser la vulnérabilité avec l’aléa. Le résultat de ces croisements que nous avons codifiés débouche sur une carte globale de niveaux de risque
The upper basin of the oued Djemaa which includes to the mountain of Djurdjura is affected by an important morphogenesis. The ground movements introduces a large variety in the study area and play a preponderant role in the evolution of mountainsides. The geomorphology detailed study an investigation into the local populations, geotechtonic and analyses it sedimentology of displaced trainings allows us to do ground typology movement and to chow theire development factors and their location. The big rainfalls of winter and sprinter are the origin of these ground movements and gully erosions, but exposition and lithology allow to understand different forms on northern and southern slope. Human activities play more and more an important role in morphogenesis acceleration. In this study, a geographical information system has been used to provide degradation maps of risks of which are tools for planning and management of soil using in the upper basin of the oued Djemaa. He allows to cross vulnerability witch vagary. The result of these crossroads which we codified results in a total map of risk levels

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Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico
The research area is located on the county of Tibau do Sul, in the east coast of Rio Grande do Norte State, about 80km south of the capital Natal. The tourism represents the main income activity and Pipa beach is the most visited beach in the city, annually receives a large influx of domestic and foreign tourists. Some recent studies have reported the occurrence of coastal erosion in this littoral, being the main objective of the research, analyze the existing coastal erosion, through two methodologies, the geoenvironmental mapping and beach morphodynamics. The geoenvironmental mapping was done from oblique aerial photographs and field visits, which sought to carry out first the geomorphological mapping, with the purpose of analyzing features that suggest susceptible areas to erosion, as areas without protection of natural dunes, marine terraces, or sandstones (beach-rocks and ferruginous sandstones), areas with the presence of gullies and stretches where the sea-cliffs were in direct contact with the action of the sea, representing the beginning of the beach profile. In the morphodynamic study sought to carry out the survey of the physical and morphological characteristics, the analysis of sediment grain of the beaches and finally the analysis of the morphodynamic parameters to generate a table of risk to erosion by sector of the beach. The morphodynamic parameters were defined by the methodology proposed by Short (2006), in which considers different patterns of dynamism on beaches with characteristics favorable and unfavorable to erosive profiles. The maps indicated different levels of risk to the segments of the beaches analyzed, suggesting risk to erosion low and low to moderate only in areas north and northwest of the beaches of Madeiro and Curral, and levels of moderate and high risk sectors in the south and southeast of these beaches . The beach of Pipa showed moderate levels of risk and moderate to high at the ends and high risk to erosion in the central portion. The study of the coastal environment, its morphological evolution, and areas with problems of erosion, are of fundamental importance to assist coastal management policies, giving grants for planning activities undertaken in these regions
A ?rea da pesquisa localiza-se no munic?pio de Tibau do Sul, situado na costa leste do Estado do Rio Grande do Norte, cerca de 80 km a sul da capital Natal. O turismo representa a principal atividade geradora de renda e a praia de Pipa, a mais conhecida do munic?pio, recebe anualmente um grande fluxo de turistas nacionais e estrangeiros. Alguns estudos recentes relatam a ocorr?ncia de eros?o costeira em pontos desta regi?o litor?nea, sendo o objetivo principal da pesquisa, analisar a eros?o costeira existente, atrav?s de duas metodologias, o mapeamento geoambiental e a morfodin?mica praial. O mapeamento geoambiental foi realizado a partir de fotografias a?reas obl?quas e visitas a campo, onde buscou-se realizar primeiramente o mapeamento geomorfol?gico, com o objetivo de analisar fei??es que sugerem ?reas suscept?veis ? eros?o, como zonas sem prote??o natural de dunas, terra?os marinhos, ou arenitos (de praia e ferruginosos), ?reas com presen?a de ravinamentos e trechos onde as fal?sias encontravam-se vivas, ou seja, representando o in?cio do perfil praial, em contato direto com a a??o do mar. No estudo morfodin?mico buscou-se realizar o levantamento das caracter?sticas f?sicas e morfol?gicas, a an?lise granulom?trica dos sedimentos das praias e por fim a an?lise dos par?metros morfodin?micos para gerar uma tabela de risco ? eros?o por setor praial. Os par?metros morfodin?micos foram definidos atrav?s da metodologia proposta por Short (2006), em que considera diferentes padr?es de dinamismo em praias com caracter?sticas favor?veis e desfavor?veis a perfis erosivos. Os mapas indicaram diferentes n?veis de risco para os segmentos das praias analisadas, sugerindo risco ? eros?o baixo e baixo a moderado apenas nos setores norte e noroeste das praias do Madeiro e Curral, e n?veis de risco moderado a alto nos setores sul e sudeste destas praias. A praia de Pipa apresentou n?veis de risco moderado e moderado a alto nas extremidades e alto risco ? eros?o na por??o central. O estudo do ambiente costeiro, de sua evolu??o morfol?gica, e de ?reas com problemas de eros?o ? de fundamental import?ncia para auxiliar pol?ticas de gerenciamento costeiro, dando subs?dios para o planejamento das atividades desenvolvidas nestas regi?es

[ES] Las playas son espacios costeros que desarrollan numerosas funciones ambientales. Éstas proporcionan importantes beneficios a la sociedad y a las comunidades costeras, entre las que destacan la función ecológica, el suministro de protección para los territorios costeros y el hecho de que constituyen un recurso básico de la industria turística. De forma ligada al cambio climático, así como a acciones humanas que alteran el dinamismo natural de la costa, las playas están experimentando procesos erosivos cada vez más dañinos que afectan a su integridad física y al mantenimiento de sus funciones. La gestión de las playas en muchas ocasiones no se encuentra adaptada a las particularidades de los diferentes segmentos costeros. La toma de decisiones no se sustenta en información suficiente sobre las características, el dinamismo y el estado actual de las playas, dando lugar a soluciones cortoplacistas o ineficaces. Las características geomorfológicas son esenciales en el desarrollo de sus funciones al condicionar sus dimensiones físicas y su comportamiento frente a la acción del mar. Por ello, su caracterización de forma detallada y actualizada es necesaria para llevar a cabo acciones eficientes, permitiendo virar hacia una gestión costera más ecosistémica y sostenible. Las técnicas de teledetección presentan una gran capacidad para la adquisición de datos de la superficie terrestre. En concreto, los satélites Sentinel-2 y Landsat (5, 7 y 8) permiten disponer de forma gratuita imágenes de resolución media con cobertura mundial y alta frecuencia de revisitado. Los algoritmos de extracción de la línea de costa desarrollados recientemente por el Grupo de Cartografia GeoAmbiental y Teledetección (CGAT - UPV) permiten definir sobre estas imágenes la posición de la línea de costa, constituyendo datos potencialmente útiles para describir la morfología de las playas y su dinamismo. Universalizar su aplicación requiere su testeo y validación en diferentes tipos de costa. Para ello, el proceso de extracción ha sido adaptado para su explotación en entornos mareales, y las líneas de costa resultantes han sido evaluadas ante diferentes condiciones oceanográficas ofreciendo una precisión cercana a los 5 m RECM (raíz del error cuadrático medio). Teniendo en cuenta las necesidades de información para la gestión existentes, a partir de estas líneas de costa se propone derivar indicadores que permitan caracterizar la geomorfología de las playas y monitorizar sus cambios. Para ello, las metodologías propuestas aseguran una gestión eficiente de grandes volúmenes de líneas de costa, siendo así capaces de caracterizar las playas cubriendo grandes territorios y periodos de tiempo. Así se derivan el ancho de playa y el tamaño de los granos de sedimento como indicadores objetivos y fácilmente comprensibles de la geomorfología de la playa. La modelización espacio-temporal del estado y los cambios de la línea de costa y de la anchura posibilita monitorizar la respuesta de las playas a temporales y a actuaciones antrópicas, permitiendo analizar los cambios ocurridos cada pocos días hasta cubrir décadas. Su cobertura espacial junto a la integración con otras bases de datos cartográficas permite caracterizar la influencia de la geomorfología de la playa en el desempeño de sus funciones, permitiendo un análisis holístico de la costa a escala regional. Las metodologías desarrolladas en esta tesis y los indicadores derivados desde la teledetección brindan apoyo para dotar de criterios y priorizar las acciones de los gestores. Se contribuye así a llenar el espacio existente entre la disponibilidad de técnicas para obtener información remota y su aplicación en los procesos de toma de decisiones sobre la costa.
[CAT] Les platges són espais costaners que desenvolupen nombroses funcions ambientals. Aquestes proporcionen importants beneficis a la societat i comunitats costaneres, entre les quals destaquen la funció ecològica, el subministrament de protecció per als territoris costaners i el fet que constitueixen un recurs bàsic de la indústria turística. De forma lligada al canvi climàtic, així com a accions humanes que alteren el dinamisme natural de la costa, les platges estan experimentant processos erosius cada vegada més nocius que afecten la seua integritat física i al manteniment de les seues funcions. La gestió de les platges en moltes ocasions no es troba adaptada a les particularitats dels diferents segments costaners. La presa de decisions no es sustenta en informació suficient sobre les característiques, el dinamisme i l'estat actual de les platges, donant lloc a solucions curtterministes o ineficaces. Les característiques geomorfològiques són essencials en el desenvolupament de les seues funcions en condicionar les seues dimensions físiques i el seu comportament enfront de l'acció de la mar. Per això, la seua caracterització de manera detallada i actualitzada és necessària per a dur a terme accions eficients, permetent virar cap a una gestió costanera més ecosistèmica i sostenible. Les tècniques de teledetecció presenten una gran capacitat per a l'adquisició de dades de la superfície terrestre. En concret, els satèl·lits Sentinel-2 i Landsat (5, 7 i 8) permeten disposar de manera gratuïta d'imatges de resolució mitjana amb cobertura mundial i alta freqüència de captura d'informació a un mateix punt. Els algorismes d'extracció de la línia de costa desenvolupats recentment pel Grup de Cartografia Geo-Ambiental i Teledetecció (CGAT - UPV) permeten definir sobre aquestes imatges la posició de la línia de costa, constituint dades potencialment útils per descriure la morfologia de les platges i el seu dinamisme. Universalitzar la seua aplicació requereix el seu testatge i validació en diferents tipus de costa. Per a això, el procés d'extracció ha sigut adaptat per a la seua explotació en entorns mareals, i les línies de costa resultants han sigut avaluades davant diferents condicions oceanogràfiques oferint una precisió pròxima als 5 m RMSE (arrel de l'error quadràtic mitjà). Tenint en compte les necessitats d'informació per a la gestió existents, a partir d'aquestes línies de costa es proposa derivar indicadors que permeten caracteritzar la geomorfologia de les platges i monitorar els seus canvis. Per a això, les metodologies proposades asseguren una gestió eficient de grans volums de línies de costa, sent així capaces de caracteritzar les platges cobrint grans territoris i períodes de temps. Així es deriven l'ample de platja i la grandària dels grans de sediment com a indicadors objectius i fàcilment comprensibles de la geomorfologia de la platja. La modelització espai-temporal de l'estat i els canvis de la línia de costa i de l'amplària possibilita monitorar la resposta de les platges a temporals i a actuacions antròpiques, permetent analitzar els canvis ocorreguts cada pocs dies fins a cobrir dècades. La seua cobertura espacial al costat de la integració amb altres bases de dades cartogràfiques permet caracteritzar la influència de la geomorfologia de la platja en l'acompliment de les seues funcions, permetent una anàlisi holística de la costa a escala regional. Les metodologies desenvolupades en aquesta tesi i els indicadors derivats des de la teledetecció brinden suport per a dotar de criteris i prioritzar les accions dels gestors. Es contribueix així a omplir l'espai existent entre la disponibilitat de tècniques per a obtenir informació remota i la seua aplicació en els processos de presa de decisions sobre la costa.
[EN] Beaches are coastal spaces that perform numerous environmental functions. They provide important benefits to society and coastal communities, including the ecological function, the provision of protection for coastal territories, and constitute a basic resource for the tourism industry. Due to climate change and human actions that alter the natural dynamism of the coast, beaches are experiencing increasingly harmful erosive processes that affect their physical integrity and the maintenance of their ecological functions. Beach management is often not adapted to the particularities of the different coastal segments. Decision-making is not based on sufficient information about characteristics, dynamism, and current state of beaches, resulting in short or ineffective solutions. Geomorphological characteristics are essential in the development of beach functions as they condition their physical dimensions and their behavior in response to the action of the sea. Therefore, their detailed and updated characterization is necessary to carry out efficient actions, allowing a more ecosystemic and sustainable coastal management. Remote sensing techniques have a great capacity for acquiring data from the land surface. In particular, Sentinel-2 and Landsat (5, 7, and 8) satellites freely provide medium resolution images with global coverage and high-revisit frequency. The algorithms for extracting the water/land interface recently developed by the Geo-Environmental Cartography and Remote Sensing Group (CGAT - UPV) allow defining the position of the shoreline on these images, constituting potentially useful data to describe beach morphology and dynamics. Universalizing their application requires testing and validation at different coastal types. For this purpose, the extraction process has been adapted for exploitation in tidal environments, and the resulting shorelines have been assessed under different oceanographic conditions offering an accuracy close to 5 m RMSE (Root-Mean-Square Error). From these shorelines, and taking into account the existing information needs for management, it is proposed to derive indicators to characterize the geomorphology of the beaches and to monitor their changes. To this end, the proposed methodologies ensure the efficient management of large volumes of shorelines, being able to characterize the beaches along broad coastal segments and periods. Thus, beach width and sediment grain size are derived as objective and easily understandable indicators of the beach geomorphology. Spatial-temporal modeling of the state and changes of shoreline position and beach width makes it possible to monitor the response to storms and anthropogenic actions, allowing to analyze changes that occur every few days or over decades. The large spatial coverage together with the integration with other cartographic databases allows characterizing the influence of beach geomorphology in the performance of its functions, offering a holistic view of the coast from a regional scale. The methodologies developed in this thesis and the indicators derived from remote sensing provide support and criteria for prioritizing the actions of managers. This contributes to fill the gap between the availability of techniques to obtain remote information and its application in the coastal decision-making process.
This research integrates findings and results obtained within the framework of the contract FPU15/04501 granted to the author by the Spanish Ministry of Education, Culture, and Sports, which has allowed this doctoral thesis to become a reality. The research has been supported by the funds of the project RESETOCOAST, by the Ministry of Economy, Industry, and Competitiveness (chapters 2 to 5), and the project MONOBESAT PID2019-111435RB-I00 by the Ministry of Science, Innovation, and Universities (chapter 6). About my stay in Portugal, it was possible with the funds of the Erasmus+ program. The contribution of Ó. Ferreira was funded by EW-COAST (PTDC/CTA-OHR/28657/2017) and by FCT and Univ. Algarve through the grant UID/MAR/00350/2013, while S. Costas’ was funded by IF/01047/2014. The following institutions have provided free access to essential data for the development of the publications that constitute this thesis: ESA and USGS for the satellite imagery; Puertos del Estado, and the Portuguese Hydrographic Institute in collaboration with CIMA for supplying oceanographic data; Ministry MITECO and DGSCM for data regarding beach sedimentology and nourishments.
Cabezas Rabadán, C. (2021). Beach Morphology and its Dynamism from Remote Sensing for Coastal Management Support [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/165076
TESIS

Les versants viticoles en Côte-d’Or (Bourgogne, France) présentent une forte diversité de sols résultant d’interactions entre des facteurs naturels et des facteurs anthropiques opérant à diverses échelles spatio-temporelles. Le sol représente un enjeu majeur en viticulture, car il détermine en partie la qualité de la production viticole. Or, il est soumis à d’importantes dégradations causées par l’érosion. Pour mieux gérer ce patrimoine sol et pérenniser la viticulture côte d’orienne, une meilleure connaissance de celui-ci est nécessaire. Ce travail a pour objectifs de caractériser les sols viticoles et d’identifier les facteurs qui contribuent à leur diversité par une approche interdisciplinaire croisant la géologie, la géomorphologie, la pédologie, l’histoire de l’occupation du sol et des pratiques. Les données ont été acquises à très haute résolution spatiale à partir de diverses méthodes d’imagerie i.e. télédétection par imagerie, géophysique de subsurface et modèle numérique de terrain. À l’échelle du versant, les cartes pédologiques produites à grande échelle permettent de discuter du modèle d’organisation des sols. À l’échelle de la parcelle, ces cartes mettent en évidence l’impact de l’homme sur la diversité des sols, par son rôle sur la structure du parcellaire et l’intensité de l’érosion notamment. La diversité des sols viticoles dépend de l’échelle spatiale à laquelle ils sont observés. À l’échelle du versant, les sols évoluent en fonction des variations du substrat géologique et de la topographie, suivant le modèle de topolithoséquence. À l’échelle de la parcelle, les variations du sol, telles que son épaisseur et son statut organique, peuvent être appréhendées, permettant d’en prédire le comportement agronomique. L’influence de l’homme se marque à la fois sur la structure du parcellaire et par les pratiques culturales anciennes et actuelles. Il participe ainsi à la construction des terroirs, à travers son action sur la diversité des sols
The Burgundian vineyard hillslopes (Côte-d’Or, France) exhibit a high diversity of soils resulting from the combination of several natural and anthropogenic factors acting at various spatio-temporal scales. The soil types have major role in viticulture, since they partly determine wine-growing quality. However, soil undergoes important degradation caused by hydric erosion and vineyard management practices. To control this soil heritage for a sustained viticulture in Côte-d’Or, a better knowledge of soil is necessary. The objectives of this work is to characterise vineyard soils and to identify the factors governing their diversity using an interdisciplinary approach crossing geology, geomorphology, pedology and history of soil land use and vineyard management practices. Data have been acquired at a high spatial resolution from different imagery methods i.e. remote sensing, subsurface geophysics, and digital terrain model. At the hillslope scale, high resolution soil maps permit to predict soil agronomical comportment and discuss the spatial soil organisation of vineyard hillslope soils. At the plot scale, these maps highlight the human impact on soil diversity through its role on landscape structure and erosion intensity. Our work shows that the soil diversity of the vineyard hillslopes depends on the spatial scale used to analyse this diversity. At the hillslope scale, soil is gradually evolving along the slope, and is controlled by the geological substrate and topographical variations, and responds to topolithosequence model. At the plot scale, variations of soil thickness and organic status are taken into account and permit to predict soil agronomic behaviour. This soil diversity is partly related to human impact, due by both historical and present vineyard management practices. It appears that human activities have a past and present influence on the terroir construction in Côte-d’Or, through its action on soil diversity

Orientador: Marcílio Vieira Martins Filho
Coorientador: José Marques Júnior
Coorientador: Diego Silva Siqueira
Banca: Walter Maccheroni Junior
Banca: Newton La Scala Junior
Banca: Marcos Guimarães de Andrade Landell
Banca: Teresa Cristina Tarle Pissarra
Resumo: A busca por ferramentas que estimem a erosão usando técnicas mais rápidas e menos onerosas e não impactantes ao ambiente são assuntos em ascensão. O objetivo deste trabalho foi estimar a predisposição à erosão em Latossolos por meio da cor obtida por Espectroscopia de Reflectância Difusa (ERD). Este proposito melhora as estratégias de manejo e conservação do solo e da água em áreas de expansão e reforma de cana-de-açúcar, evitando os impactos ambientais negativos. A área de estudo localiza-se no município de Guatapará (SP), com os solos: Latossolo Vermelho distrófico, Latossolo Vermelho distroférrico, Latossolo Vermelho eutroférrico e Latossolo Vermelho-Amarelo distrófico. Foram coletadas 9 amostras de solo representativas da área em transeção de 2600 m (1 ponto a cada 289 m) e mais 129 pontos em malha de densidade amostral de 1 ponto a cada 3 ha, na profundidade de 0,00 a 0,20 m. Para as 138 amostras coletadas, foram determinados os atributos mineralógicos, físicos, químicos e da cor. Os valores da Ki, Kr e c foram estimados por meio de equações propostas por Flanagan e Linvingston (1995). A variabilidade dos atributos do solo foi descrita por meio da construção dos gráficos boxplot em função de 3 compartimentos previamente observados. Foi possível identificar os limites entre os compartimentos com diferentes potenciais erosivos, não identificados pela carta de Munsell. Regressões lineares simples foram estabelecidas entre Ki, Kr e c e os atributos mineralógicos e aqueles ... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: The tools to estimate the erosion using faster techniques, which are also less expensive and inoffensive to the environment, are issues on the rise. The aim of this work was to estimate erosion predisposition in Latosoils using the color obtained by Diffuse Reflectance Spectroscopy (DRS). This purpose improves the strategies to soil and water conservation and management in areas of sugarcane expansion and reform, as well as avoids negative environmental impacts. The study was carried out in the municipality of Guatapará (SP), with the following soil types: Dystrophic Red Latosol, oxisol, eutrudox red latosol, and Brazilian Oxisol. 9 representative soil samples were collected in a transect with 2600 m (1 point in each 289 m), and another 129 soil samples into a grid of sample density of 1 point per 3 ha, in the depth of 0.00 to 0.20m. For the total 138 soil samples collected, mineralogical, physical, chemical and color attributes of the soil were determined. Interrill and Rill erodibility and critical soil shear stress were estimated using equations proposed by Flanagan and Linvingston (1995). The variability of the soil attributes was described using boxplot graphs in function of three compartments previously studied in the area. It was possible to identify the limits between compartments and different erosive potential not identified by the Munsell Soil Color Charts. Simple linear regressions were established to Interrill and Rill erodibility, and critical soil shear stress with soil mineralogical attributes, and those related to soil color. The most efficient color components to estimate Interrill erodibility were Hue (88% of precision), Rill erodibility, Value (62% of precision) and critical soil shear stress, Chroma (86%). Spatial dependence analyzes show that the hue can estimate those erosion factors with 68% of prec... (Complete abstract click electronic access below)
Doutor

A BR 116, no Rio Grande do Sul, perfaz uma extensão total de 653,8 quilômetros, iniciando na divisa entre SC e RS, na ponte sobre o Rio Pelotas, entre Lajes e Vacaria, prolongando-se até Jaguarão. A sua importância econômica no estado decorre do fato de ser um corredor que liga o norte do Rio Grande do Sul ao porto de Rio Grande (através da BR 392) e à fronteira com o Uruguai. A duplicação da BR-116 visa o escoamento da produção até o Porto de Rio Grande e a distribuição de produtos e bens que ingressam pelo Porto ou pela fronteira. Atualmente, as obras de duplicação encontram-se executadas em 50-60 % e parcialmente paralisadas (cada trecho/lote tem uma situação diferente). Este trabalho dedicou-se ao mapeamento geotécnico dos condicionantes de ruptura dos taludes de cortes rodoviários da BR-116, entre os municípios de São Lourenço do Sul e Barra do Ribeiro (RS). A investigação ocorreu por meio da análise dos taludes em campo, estudando as relações geológicas e pedológicas que condicionam as instabilidades situadas ao longo do trecho entre os quilômetros 332 e 477. O mapeamento geotécnico executado incluiu o levantamento da localização geográfica (coordenadas geográficas, e km da rodovia) de todos os cortes de estrada (taludes) existentes no trecho escolhido, bem como o levantamento fotográfico e a coleta de dados como altura, inclinação, extensão, cota altimétrica, medidas estruturais, medidas e descrição dos horizontes pedogenéticos, problemas geotécnicos, comportamento mecânico, fluxo de água superficial, nível do lençol freático, descrição geológica, descrição do nível de intemperismo e coleta de amostra para ensaios geotécnicos e difratometria de raios X Após as descrições de campo, os talude 8, 15 e 30 foram definidos como taludes representativos para análise mineralógica através de difração de raios X e caracterização dos argilo-minerais através de microscópio eletrônico de varredura. O talude 8 ainda contou com ensaios de cisalhamento direto para caracterização geomecânica do horizonte C. Esta análise permitiu definir que o principal condicionante para as rupturas de taludes na BR-116, trecho Sul, está na exposição do horizonte C, que induz diferentes tipos de processos erosivos sobre o mesmo. As investigações mostraram que a exposição do horizonte C faz com que a água da chuva aja na erosão direta do sopé do talude, ou na formação de canaletas e piping pela remoção de finos, os quais evoluem para bossorocas. As estruturas geológicas reliquiares preenchidas por caulinita também incrementam os processos erosivos, pela retirada da base estrutural de todo o corte. Assim, os horizontes A e B e a vegetação logo acima perdem sustentação e a gravidade determina o rompimento do talude em escorregamentos rotacionais. A continuidade dos eventos pluviométricos e, portanto, dos processos erosivos induzem novas rupturas em alguns taludes, ou na erosão direta do material escorregado para a base do talude, removendo material para as drenagens adjacentes.
The BR-116 is one of the most important longitudinal highways in Rio Grande do Sul state (RS, Brazil). The highway has 653.8 kilometers, starting at the bridge over the Pelotas River, and extending to Jaguarão city. It is part of an important economic corridor, that connects the north of RS to the Rio Grande Harbor (through BR 392) and Uruguay border. Therefore, the importance of the highway to the economic outflow from the state. The BR-116 duplication effort is actually halfway to the end, each segment in a different situation, and is slowly going on. This work was focused on mapping the geotechnical controlling factor for road cuts slidings, that occurred between São Lourenço do Sul and Barra do Ribeiro municipalities (RS) along BR-116 highway. The geotechnical investigation was carried out through fieldworks road cut slopes analysis, which included geology and pedology slopes characterization along the 332 and 477 kilometer of the BR-116 highway. The geotechnical field mapping procedures include recording and analyzing the geographic location (geodetic coordinates, and altimeter), photographic survey, and mainly the height, inclination, extension, structural features measurements, measure and description of pedogenetic horizons, geotechnical problems, mechanical behavior, surface water flow, groundwater level, geological description, description of weathering level and sample collection for all road cut slopes that show sliding or erosional features. The slopes numbered 8, 15 and 30 were defined as representative slopes for mineralogical analysis (X-ray diffraction and scanning electronic microscope) This analyses allowed to define that the main controlling factor for the road cut sliding along BR-116 under duplication is the exposure of the pedogenetic C horizon, since this enables different erosional processes upon it. The investigation has shown that the rainwater can acts directly on the footwall erosion, or even in the formation of channels and piping, which evolve to ravines. The relict geological structures weathered to kaolinite additionally contribute to the erosion processes. In such a scenario, the decreasing structural support due to C horizon erosion enable gravity to act upon pedogenetic A and B horizons, as well as on the vegetation cover just above, and cause rotational sliping on the road cut slopes. The subsequent pluviometric events contribute to additional direct erosion on slope footwall, to material removal to adjacent drainage channels, and, consequently, to repeated sliping in some slopes.

A bacia do Ribeirão do Meio é uma área com sérios problemas associados ao processo de erosão hídrica. A carta de susceptibilidade à erosão foi obtida a partir do uso combinado de um conjunto de ferramentas de trabalhos como: mapeamento geológico-geotécnico e o geoprocessamento; fundamentais para a definição das potencialidades e limitações do meio físico. Os procedimentos adotados durante o mapeamento geológico-geotécnico permitiram obter informações de caráter qualitativo e quantitativo dos materiais inconsolidados, os quais foram submetidos a um processo de análise para a sua caracterização. Dentre as técnicas de trabalho merece destaque o ensaio de infiltração in situ tanto pela qualidade e importância das informações obtidas, quanto pelo baixo custo financeiro. Os critérios estabelecidos para avaliação dos principais fatores associados ao fenômeno de erosão, foram: índice de erodibilidade, declividade do terreno, espessura dos materiais inconsolidados, textura do material, condutividade hidráulica, origem do material, presença ou não da cobertura vegetal e processo de ocupação das terras. Durante o processo de análise das informações as características hidráulicas e os índices de erodibilidade foram correlacionados a todas outras propriedades dos materiais inconsolidados, e revelaram-se fortes parâmetros de avaliação frente aos processos erosivos. Todas essas informações, foram introduzidas no sistema de tratamento de dados do geoprocessamento para a apresentação em forma de documentos cartográficos e cruzamento das informações que culminaram no reconhecimento de cinco classes susceptíveis à erosão por escoamento concentrado.
This research proposes the elaboration of the Ribeirão do Meio river\'s basin erosion susceptibility map. This area was chosen due to serious problems related to the gully erosion observed on the site. This cartographic document was obtained using tools such as the Geological-Geotechnical Mapping and Geoprocessament; essential to define the physical environment\'s potentialities and limitations. The procedures adopted during the geological-geotechnical mapping made it possible to obtain qualitative and quantitative information of the unconsolidated material, which were analyzed and characterized. The in situ infiltration test must be emphasized among the other work techniques due to its quality, low cost and importance of the obtained information. The criteria established to evaluate the main factors were: erodibility index, declivity, the unconsolidated material\'s thickness, material texture, hydraulic conductivity, the material\'s source, possible presence of vegetable covering and antropic activity process. During the information analysis process, the hydraulic characteristics and the erodibility indexes were correlated to all other properties of the unconsolidated materials, and among the parameters used to evaluate the erosive process the hydraulic characteristics and erodibility indexes provided the most consistent results. Cartographic documents and the other information were crossing culminating on the recognition of five susceptibility classes of erosion for concentrated drainage.

Round Island is a 219 hectares islet north of the Mauritian mainland and has been classified as a Nature Reserve since 1957. The island has been subjected to human influence in the form of land degradation through introduced grazing animals (goats and rabbits) which has detrimentally affected the floral and faunal ecology of the island. Since the removal of the grazers, intensive conservation management has been undertaken to restore Round Island’s unique ecological status. The aim of this research project was to investigate erosion phenomena at specific study sites on Round Island through field-based classification and mapping procedures and describe physical soil characteristics. A modified version of the SARCCUS (1981) Erosion Classification system was used to classify linear erosion forms in the field, based on morphometric parameters. The effect of rock hardness was also assessed to determine lithological controls on bedrock-incised erosion features. Given the size of Round Island and the extensive nature of erosion, five study sites were chosen for the soil and erosion assessment. An additional two gully networks, ‘camp’ and ‘big’ gully were chosen to allow the investigation of an entire erosion system. Soils are thin and discontinuous, with a sandy texture and are poorly sorted. The Helipad habitat has the coarsest soils indicative of wind erosion where the deflation of fines leaves a coarser gravel pavement. No significant differences are found between sites for soil physical properties, with the exception of pH where the Summit has a significantly lower pH than the Helipad (Mann- Whitney U test, z= -2.21, p= 0.03) and Rock Slab (Mann- Whitney U test, z= -2.93, p< 0.01) habitat regions. No linear erosion forms are found on the soils of Round Island, however bedrock incised rills and gullies extensively occur. The Summit, Rock Slab and Palm Savannah habitats represent erosion processes along a profile gradient on the steep, convex western slope. The Summit habitat is subject predominantly to sheetwash and wind erosion, with the presence of two bedrock-incised rills of moderate severity. The Rock Slab region is predominated by parallel, shallow bedrock rills and gullies running downslope with moderate and slight severity, respectively. Soil and vegetation cover is highly variable within the region. Downslope, the Palm Savannah region is subject to moderate gully erosion with an irregular morphology. Soil is transported during rainfall within the gully channels where it is ultimately lost to sea. The two large gully systems, ‘camp’ and ‘big’ gully represent erosion of the highest severity on Round Island. The gullies have their starting points on the mid- upslope regions as rills, which increase in width and depth downslope, as indicated by decreasing width: depth ratios. The gullies have their end point at sea, both with a severity of very severe bedrock-gully erosion. During periods of intense rainfall the bedrock-incised gullies act as transport channels for sediment which is ultimately lost to sea. Little sediment is able to remain and this is exemplified by a lack of vegetation. This is a natural cycle where conservation efforts will remain ineffective. In addition to morphology, rock hardness was assessed using a Schmidt Hammer for the bedrock incised forms. The rate of erosion of the bedrock dominated channels depends on various factors such as rock strength, sediment supply and grain size. The predominant rock type on Round Island is tuff which is a relatively weak volcanic rock, as indicated by low mean Schmidt Hammer R-values, implicating higher expected bedrock erosion rates.
Mini-dissertation (MSc)--University of Pretoria, 2015.
tm2015
Zoology and Entomology
MSc
Unrestricted

At present one of the challenges of soil erosion research in South Africa is the limited information on the location of gullies. This is because traditional techniques for mapping erosion which consists of the manual digitization of gullies from air photos or satellite imagery, is limited to expert knowledge and is very time consuming and costly at a regional scale (50-10000km²). Developing a robust, reliable and accurate means of mapping gullies is a current focus for the Institute for Soil, Climate and Water Conservation (ISCW) of the Agricultural Research Council (ARC) of South Africa. The following thesis attempted to answer the question whether “medium resolution multi-spectral satellite observations, such as Landsat TM, combined with information extraction techniques, such as Vegetation Indices and multispectral classification algorithms, can provide a semi-automatic method of mapping gullies and to what level of accuracy?”. More specifically, this thesis investigated the utility of three Landsat TM-derived Vegetation Index (VI) techniques and three classification techniques based on their level of accuracy compared to traditional gully mapping methods applied to SPOT 5 panchromatic imagery at selected scales. The chosen study area was located in the province of KwaZulu-Natal (KZN) South Africa, which is considered to be the province most vulnerable to considerable levels of water erosion, mainly gully erosion. Analysis of the vegetation indices found that Normalized Difference Vegetation Index (NDVI) produced the highest accuracy for mapping gullies at the sub-catchment level while Transformed Soil Adjusted Vegetation Index (TSAVI) was successful at mapping gullies at the continuous gully level. Mapping of gullies using classification algorithms highlighted the spectral complexity of gullies and the challenges faced when trying to identify them from the surrounding areas. The Support Vector Machine (SVM) classification algorithm produced the highest accuracy for mapping gullies in all the tested scales and was the recommended approach to gully mapping using remote sensing

Accelerated soil erosion is drawing a growing attention with the recognition that the rate of soil loss is too great to be met by soil formation rate. Weenen Game Reserve (WGR) is an area with an unfortunate history of prolonged soil erosion due to excessive overgrazing that led to severe land degradation with prominent visible scars. This problem triggered the general objective of estimating and mapping potential soil erosion in WGR. Assessing soil loss in the area objectively has important implications for the overall management plans as it is reserved for ecological recovery. The most important variables that affect soil erosion are considered as inputs in soil loss estimation models. In this study the RUSLE model, which uses rainfall, soil, topography, and cover management data, was employed. From the rainfall data, an erosivity factor was generated by using a regression equation developed by relating EI30 index and total monthly rainfall. The soil erodibility factor was calculated using the soil erodibility nomograph equation after generating the relevant data from laboratory analysis of soil samples gathered from the study area. Using exponential ordinary kriging, the point values of this factor were interpolated to fill in the non-sampled areas. The topographic effect, which is expressed as the combined impact of slope length and slope steepness, was extracted from the DEM of the study area using the flow accumulation method. For mapping of the land cover factor, in situ measurements of cover from selected sites were undertaken and assigned values from the USLE table before being related with MSAVI of Landsat 7 ETM+ image. These values were then multiplied to get the final annual soil loss map. The resulting potential soil loss values vary between 0 and 346 ton ha-1 year-l with an average of 5 ton ha-1 year-l. About 58% of the study area experiences less than 1 ton ha-1 year-1 indicating the influence of the highest values on the average value. High soil erosion rates are concentrated in the central part extending as far as the south and the north tips along the eastern escarpments and these areas are the ones with the steepest slopes. The results indicate a high variation of soil loss within the study area. Nevertheless, the majority of the area falling below the average might foresee that the soil erosion problem of the area can be minimized significantly depending largely on soil management. The most important areas for intervention are the medium and low erosion susceptible parts of WGR, which are mainly found in the flatter or gently sloping landscapes. The steepest areas are mostly covered with rocks and/or vegetation and hence less effort must be spent in managing them. Overall, the reported increasing density of the vegetation community in the area that reduces the exposure of soil from the impact of direct raindrops and surface-flowing water must be pursued further.
Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2004.

Thesis (M.Sc. (Geography)) --University of Limpopo, 2018
Soil erosion, which is a critical component of land degradation, is one of the serious global environmental problems often threatening food security, water resources, and biodiversity. A comprehensive assessment and analysis of remote sensing applications in the spatial soil erosion mapping and monitoring over time and space is therefore, important for providing effective management and rehabilitation approaches at local, national and regional scales. The overall aim of the study was to assess the use of multispectral remote sensing sensors in mapping and monitoring the spatio-temporal variations in levels of soil erosion in the former homelands of Sekhukhune district, South Africa. Firstly, the effectiveness of the new and freely available moderate-resolution multispectral remote sensing data (Landsat 8 Operation Land Imager: OLI and Sentinel-2 Multi-Spectral Instrument: MSI) derived spectral bands, vegetation indices, and a combination of spectral bands and vegetation indices in mapping the spatio-temporal variation of soil erosion in the former homelands of Sekhukhune District, South Africa is compared. The study further determines the most optimal individual sensor variables that can accurately map soil erosion. The results showed that the integration of spectral bands and spectral vegetation indices yielded high soil erosion overall classification accuracies for both sensors. Sentinel-2 data produced an OA of 83, 81% whereas Landsat 8 has an OA of 82.86%. The study further established that Sentinel-2 MSI bands located in the NIR (0.785-0.900 μm), red edge (0.698-0.785μm) and SWIR (1.565-2.280 μm) regions were the most optimal for discriminating degraded soils from other land cover types. For Landsat 8 OLI, only the SWIR (1.560-2.300 μm), NIR (0.845-0.885 μm) region were selected as the best regions. Of the eighteen spectral vegetation indices computed, Normalized Difference Vegetation Index (NDVI) and Soil Adjusted Vegetation Index (SAVI) and Global Environmental Monitoring Index (GEMI) were selected as the most suitable for detecting and mapping soil erosion. Secondly, the study assessed soil erosion in the former homelands of Sekhukhune, South Africa by applying a time-series analysis (2002 and 2017), to track changes of areas affected by varying degrees of erosion. Specifically, the study assessed and mapped changes of eroded areas (wet and dry season), using multi-date Landsat products 8 OLI and 7 Enhanced Thematic Mapper (ETM+)). Additionally, the study used extracted eroded areas and overlay analysis was performed together with geology, slope and the Topographic Wetness Index (TWI) of the area under study to assess whether and to what extent the observed erosional trends can be explained. ii Time series analysis indicated that the dry season of 2002, experienced 16.61 % (224733 ha) of erosion whereas in 2017 19.71% was observed. A similar trend was also observed in the wet season. This work also indicates that the dominant geology type Lebowa granite: and Rustenburg layered its lithology strata experienced more erosional disturbances than other geological types. Slopes between 2-5% (Nearly level) experienced more erosion and vice-versa. On the hand, the relationship between TWI and eroded areas showed that much erosion occurred between 3 and 6 TWI values in all the seasons for the two different years, however, the dry season of 2002 had a slightly higher relationship and vice-versa. We, therefore, recommend use and integration of freely and readily available new and free generation broadband sensors, such as Landsat data and environmental variables if soil erosion has to be well documented for purposes of effective soil rehabilitation and conservation. Keywords: Food security Global changes, Land degradation, Land-based ecosystems, Land management practices, Satellite data, Soil conservation, Sustainable Development; Topographic Wetness Index; Time series analysis.