Caves are valuable sites from geological , palaeontological and biological point of view. They are important biotopes of rare and endangered species. Their ecosystem is quite specific and often very independent on environment. Therefore, the caves since the beginning of science have been the subject of research , and gradually also the subject of protection. Caves can also be very attractive objects of interest of tourism. In the Czech Republic there are 14 open to the public karst caves that have regulated attendance, and their access time is subordinated to the interests of nature conservation. On the other hand, there are also a number of caves that are not secured in any way and may be a target of unregulated tourism. This dissertation discusses the evaluation and the impact of attendance on non-karst caves in the National Nature Reserve Canyon Labe, which are freely accessible. I divided the work into three parts. In the first part I dealt with quantifying the attendance of all caves in the area of interest, On the basis of collected data, I made a selection of caves , which I later focused on. In the second part of my work I focused on obtaining information about the visitors and their motivations using public inquiry survey in selected caves, In the third part I tried to analyze the impact...

This diploma thesis aims at Czech legislation related to conservation of caves both in terms of its link to the protection of caves as subterranean spaces and parts of the natural environment and of its relation to other fields of expertise, including legal studies (e.g., mining law) and other disciplines (e.g., geology, carsology). First, our attention is paid to definition of the term "cave" and to links of the term to natural sciences. Further, we analyse the development of legal conservation of caves and approaches to caves as a subject of legislation per se. The example of Slovenia - being a prominent speleological country with recognized legislation in terms of its quality and detail - is used in order to compare Czech approaches to cave conservation. Concerning the practical issues, we present an example of conservation effort devoted to one single cave in Czechia, which enables to describe functioning of legal conservation tools, including the themes where these tools overlap. We also present and discuss the only one Czech case-law dealing with the legal aspect of caves.

Over fifty small sinkholes (~1 meter in depth and width) were found in conjunction with structural damage to homes in an area south of Cleveland, TX. The local geology lacks carbonate and evaporite deposits associated with normal sinkhole development through dissolution. The morphology and distribution of sinkholes, and the geologic setting of the site are consistent with piping erosion. However, the site lacked the significant hydraulic gradient or exit points for sediment associated with traditional piping erosion. In areas of sinkholes, geophysical measurements of apparent electrical conductivity delineated anomalously high conductivity levels that are interpreted as a brine release from a nearby oil-field waste injection well. The contaminated areas have sodium adsorption ratios (SAR) as high as 19, compared to background levels of 3. Sodium has been shown to cause dispersion of soil colloids, allowing for sediment transport at very low velocities. Thus, subsurface erosion of dispersed sediment could be possible without significant hydraulic gradients. This hypothesis is backed by the observation of the depletion of colloidal particles within the E-horizon of sinkholes. However, there is a lack of precedence of waste brines initiating colloid dispersion. Also, sodium dispersion is not thought to be an important process in piping erosion in humid settings such as this one. Therefore, laboratory experiments on samples from the site area, designed to simulate field conditions, were conducted to measure dispersion verses pH, SAR and electrical conductivity (EC). Analysis of the experimental data with neural networks showed that an increase in SAR did increase dispersion. A dispersion prediction map, constructed with the trained neural network and calibrated geophysical data, showed correlation between sinkhole locations and increased predicted dispersion. This research indicates that a contaminant high in sodium content has caused colloidal dispersion, which may have allowed nontraditional subsurface erosion to occur in an area lacking a significant hydraulic gradient.

Over fifty small sinkholes (~1 meter in depth and width) were found in conjunction with structural damage to homes in an area south of Cleveland, TX. The local geology lacks carbonate and evaporite deposits associated with normal sinkhole development through dissolution. The morphology and distribution of sinkholes, and the geologic setting of the site are consistent with piping erosion. However, the site lacked the significant hydraulic gradient or exit points for sediment associated with traditional piping erosion. In areas of sinkholes, geophysical measurements of apparent electrical conductivity delineated anomalously high conductivity levels that are interpreted as a brine release from a nearby oil-field waste injection well. The contaminated areas have sodium adsorption ratios (SAR) as high as 19, compared to background levels of 3. Sodium has been shown to cause dispersion of soil colloids, allowing for sediment transport at very low velocities. Thus, subsurface erosion of dispersed sediment could be possible without significant hydraulic gradients. This hypothesis is backed by the observation of the depletion of colloidal particles within the E-horizon of sinkholes. However, there is a lack of precedence of waste brines initiating colloid dispersion. Also, sodium dispersion is not thought to be an important process in piping erosion in humid settings such as this one. Therefore, laboratory experiments on samples from the site area, designed to simulate field conditions, were conducted to measure dispersion verses pH, SAR and electrical conductivity (EC). Analysis of the experimental data with neural networks showed that an increase in SAR did increase dispersion. A dispersion prediction map, constructed with the trained neural network and calibrated geophysical data, showed correlation between sinkhole locations and increased predicted dispersion. This research indicates that a contaminant high in sodium content has caused colloidal dispersion, which may have allowed nontraditional subsurface erosion to occur in an area lacking a significant hydraulic gradient.