LiDAR (Light Detection and Ranging) is an active remote sensing system which is used to map the surface of the Earth and which can be processed to show the ground surface under the canopy cover. The aim of this study is to examine if LiDAR can be used as a method for mapping karst on the island of Gotland, what kind of karst morphologies may be identified and their geographical distribution. LiDAR was visualized in the computer platform ArcGIS and in ArcMap version 10.3 (Esri). More than 2000 karst objects were mapped using LiDAR. Of these, eight different locations including 34 potential karst objects were chosen for field control. Six different classes of karst have been identified including three classes of dolines. The results show that LiDAR can be used for mapping karst, especially the bigger karst morphologies which are easier to identify. The results from the field control show that 45 % of the small dolines, 43 % of the medium sized dolines and 33 % of the large dolines which has been mapped in LiDAR were actual dolines. For larger scale karst morphologies the success rate was almost 100 %. The method did not lend itself well to identification of sinkholes, most likely related to the very small size of these on Gotland.

The microbasin of the Sarandi little stream, that it crosses the cities of Saint Maria and Dilermando de Aguiar, situated in the State of Rio Grande do Sul, south region of Brazil, presents innumerable erosions; the most significant soil erosion on that region is well known as Buraco Fundo gully, which is also our case of study. The general goal of this dissertation was to delimitate and to characterize the geological and geotechnical materials of that soil erosion, in order to understand the parameters that influence that erosive process. As specific goals tries to evaluate the erosive marks and the pseudo-karstic relief, as well as the degree of erodibility of that materials, in order to minimize its advance. Nevertheless, this writing involved theoretical research, fieldwork and laboratory, where the assays of geotechnical characterization and direct and indirect evaluation of erodibility had been executed. The soil erosion of the Buraco Fundo gully occurs in sedimentary rocks according to direction N20º-35ºE. It results of rotational slippings and pseudo-dolines that evaluates to ridges and ravines. It was assayed the superficial horizon (A/B) and the sandstone layer located in the amphitheater of that soil erosion. The horizon A/B presents an arenaceous and argillaceous texture, plastic behavior and the biggest quotient of emptiness, while the sandstone did not present plasticity. The coefficient of sorption(s) was bigger in the sandstone than in the superficial horizon. Therefore, it can be foreseen that the saturation in rainy events is faster in the sandstone than in the superficial horizon. The sandstone makes the material, after the saturation, establish the superficial draining. It occurs, as consequence, the carry of fine materials. It was verified a direct relationship between the results of the slaking test and the assays of infiltrability. The sandstone showed high desagregation and high coefficient of infiltrability. The values of Pi/s had been superior to 50, for both samples; they were classified as erodible according to Nogami and Villibor (1979). The coefficient of erodibility (k) was 10 times bigger in the sandstone, which can be related to the loss of resistance due to suction and the apparent fragility of the cementing agent. The soil revealed to be very resistant cause presents organic matter , roots and fines. The results indicate the necessity of protection of this area since the initial period of erosion, in order to avoid that process of erosion reaches the rock. / A microbacia do Arroio Sarandi, nos municípios de Santa Maria e Dilermando de Aguiar/RS apresenta inúmeras erosões sendo a mais significativa uma voçoroca conhecida na região como Buraco Fundo escolhida para estudo de caso. O objetivo geral desta dissertação foi a caracterização geológico-geotécnica dos materiais da voçoroca, procurando compreender os parâmetros que influenciam no processo erosivo. Como objetivos específicos procurou-se avaliar as feições erosivas e as formas de relevo pseudo-cársticos bem como a erodibilidade dos materiais sugerindo ações para minimizar o seu avanço. Este trabalho envolveu etapa de escritório; de campo e de laboratório, onde foram executados os ensaios de caracterização geotécnica e avaliação direta e indireta da erodibilidade. A voçoroca do Buraco Fundo ocorre em rochas sedimentares segundo a direção N20º-35ºE. A evolução se dá por escorregamentos rotacionais e pseudo-dolinas que evoluem para sulcos e ravinas. Foram ensaiados o horizonte superficial (A/B) e a camada de arenito localizados no anfiteatro da voçoroca. O horizonte A/B apresenta uma textura areno-argilosa, comportamento plástico e maior índice de vazios, enquanto o arenito não apresentou plasticidade. O coeficiente de sorção (s) foi maior no arenito do que no horizonte superficial e, portanto, pode-se prever que a saturação em eventos chuvosos, seja mais rápida no arenito, fazendo com que neste material, após a saturação, se estabeleça o escoamento superficial e ocorra, como consequência, o carreamento de materiais finos. Verificou-se uma relação direta entre os resultados do ensaio de desagregação e os de infiltrabilidade, onde o arenito mostrou alta desagregação e elevado coeficiente de infiltrabilidade. Os valores de Pi/s foram superiores a 50 para ambas as amostras, classificadas como erodíveis segundo Nogami e Villibor (1979). O coeficiente de erodibilidade (K) foi 10 vezes maior no arenito o que pode estar relacionado à perda da resistência devido à sucção e a aparente fragilidade do agente cimentante. O solo, por apresentar matéria orgânica, raízes e finos mostrou-se mais resistente. Os resultados apontam para a proteção das áreas em estágio erosivo inicial evitando que o processo atinja a rocha.