Esta pesquisa integrou estudos geológicos, hidrogeológicos, geoquímicos e de isótopos estáveis no município de Sete Lagoas (MG), Brasil, com o objetivo de entender a circulação da água em terreno cárstico e propor alternativas para o seu melhor uso, a fim de se evitar problemas geotécnicos. A área é constituída por calcários neoproterozoicos da Formação Sete Lagoas, onde se desenvolveram condutos cársticos, dando origem ao aquífero homônimo, o qual está coberto por sedimentos cenozoicos inconsolidados e, ocasionalmente, por rochas metasedimentares neoproterozoicas da Formação Serra de Santa Helena. Foi observado que neste aquífero a porosidade primária é muito baixa e a secundária (micro-fraturas) é igualmente reduzida, devido ao preenchimento por calcita. O grande volume de água subterrânea migra através da porosidade terciária caracterizada dominantemente por dois planos de acamamentos carstificados e, em menor grau, por fraturas sub-verticais carstificadas. A recarga, relacionada às chuvas que ocorrem no período de outubro a dezembro, se dá através de sumidouros, entradas de cavernas e onde o calcário está sob os sedimentos cenozoicos. Um detalhado estudo avaliando os efeitos de escala permitiu também o estabelecimento da distribuição das permeabilidades do Aquífero Sete Lagoas. Outros resultados obtidos também estabeleceram que as extrações de águas subterrâneas estão associadas aos eventos geotécnicos cársticos localizados na área urbana do município. A elevada extração das águas subterrâneas faz com que o plano de acamamento carstificado mais raso, em algumas áreas, esteja inteiramente na zona não saturada, provocando os eventos geotécnicos. Um mapa de risco geotécnico identifica, a partir da litologia e do nível de água subterrânea, cinco níveis. Este tipo de mapeamento deveria orientar as extrações e os cuidados na ocupação do terreno urbano em Sete Lagoas, prevenindo ou retardando a ocorrência de novas subsidências ou colapsos. / This research integrated geological, hydrogeological, geochemical, and stable isotope studies conducted in the municipality of Sete Lagoas (MG), Brazil, in order to understand the water circulation in a karst terrain and to propose alternatives for a better water use, aiming to avoid geotechnical problems. The area is constituted by Neoproterozoic limestones from the Sete Lagoas Formation, where karst conduits were developed, giving origin to the homonymous aquifer, which is covered by Cenozoic unconsolidated sediments and, occasionally, by Neoproterozoic metasedimentary rocks from the Serra de Santa Helena Formation. It was observed that in this aquifer the primary porosity is very low and the secondary porosity (micro -fractures) is also reduced, due to the filling by calcite. The great volume of groundwater migrates through the tertiary porosity characterized by two dominant solutionally enlarged bedding planes and, to a lesser extent, by sub-vertical enlarged fractures. The recharge, related to rainfall occurring from October to December, takes place through sinkholes, caves entrances, and where the limestones are under the Cenozoic sediments. A detailed study evaluating the scale effects also allowed the establishment of permeability distributions of the Sete Lagoas Aquifer. Other results obtained also established that the groundwater extractions are associated to karst geotechnical events located in the urbanized area of the municipality. The high groundwater extractions make the shallowest solutionally enlarged bedding plane, in some points, entirely in the unsaturated zone, causing geotechnical events. A geotechnical map identifies five levels of risk, based on the lithology and the groundwater level interaction. This type of mapping should guide the groundwater extractions and caring the urban land occupation in Sete Lagoas, preventing or delaying the occurrence of new subsidences or collapses.

O presente estudo investigou a participação do H2S04, como agente corrosivo no carste do Grupo Una, na bacia de Irecê e na bacia do rio Salitre, tendo como base o monitoramento hidroquímico e a determinação de fácies hidroquímicas. A fácies escoamento superficial alogênico é caracterizada por baixos valores de pH (\'X BARRA\'=4,79 ; CV=3,15%) e dos principais cátions e ânions, com destaque para S\'O IND. 4 POT. 2-\' (x=0,57 mg/L ; CV10,32%); A fácies fluxo freático profundo carbonático representa a maior concentração de HC\'O IND. 3 POT. -\' de todo conjunto amostrado, com média igual a 359,08 mg/L. Na média as águas desta fácies encontram-se saturadas para calcita (S\'l IND. c\' = 0,02) e insaturadas para gipsita (S\'l IND. g\' = -1,51). A concentração de S\'O IND. 4 POT. 2-\' também é alta (\'X BARRA\'=204,50 mg/L ; CV 135,00%), destacando-se um ponto de amostragem que exibe elevado valor médio para \'SO IND. 4 POT. 2-\' (\'X BARRA\'= 746,07 ; CV = 13,79%); Na fácies percolação vadosa a concentração de S\'O IND. 4 POT. 2-\' é expressiva, com média igual a 305,09mg/L; Nos reservatórios subterrâneos destaca-se a alta concentração de HC\'O IND. 3\'(média - 305,10 mg/L), Índice de Saturação para calcita muito próximo do equilíbrio (S\'l IND. c\'=-0,02) e concentração média para S\'O IND. 4 POT. 2-\' (\'X BARRA\'=17,79 mg/L; CV = 52,03%); Nas nascentes cársticas observou-se alto teor de HC\'O IND. 3 POT. -\' (\'X BARRA\'=246,96 mg/L ; CV = 11,0%), S\'l IND. c\'=0,00 (0,28 a -0,37), em equilíbrio de saturação para o mineral calcita e concentração de S\'O IND. 4 POT. 2-\' (\'X BARRA\'= 19,30mg/L ; CV = 31,47%). As águas meteóricas são caracterizadas por baixas concentrações dos principais cátions e ânions, com médias inferiores a 0,5mg/L. Cálculos estequiométricos foram aplicados aos dados hidroquímicos e conclui-se que no balanço molar as águas não seguem as razões clássicas para dissolução exclusiva por ácido carbônico, mas sim, adequam-se ao sistema \'H IND. 2\'S\'O IND. 4\' - CaMgC\'O IND. 3\'. Minerais secundários de cavernas foram analisados e detectou-se ocorrências expressivas de gipsita, sob a forma de crostas, estalactites e filamentos, que, vinculadas ao ambiente de formação, indicam a participação de soluções ricas em sulfato em seus processos. O evento principal de deposição de gipsita foi associado ao rebaixamento do NA após fase de ampliação paragenética dos condutos. Análises isotópicas de \'\'delta\' POT. 13\'CHC\'O IND. 3 POT. -\' em amostras de águas subterrâneas indicam valores enriquecidos (-10,4%o PDB-V) em relação ao esperado para a reação de dissolução da rocha carbonática por ácido carbônico (-17,1%o), condição relacionada à influência de \'ANTPOT. 13 C\' oriundo da rocha por ação do ácido sulfúrico. O \'delta\' POT. 34\'S de sulfato em água subterrânea (\'X BARRA\'=17,7%o CDT) é levemente empobrecido em relação à pirita (\'X BARRA\'=21,3%o), com valores na faixa de amplitude prevista para o processo de oxidação, condição que atesta a participação de ácido sulfúrico na dissolução da rocha carbonática. Análises microbiológicas na água subterrânea do aqüífero cárstico indicaram a presença de bactérias do gênero Acidithiobacillus e bactérias redutoras de sulfato (BRS), ambas presentes no ciclo do enxofre e responsáveis pela produção de ácido sulfúrico. Neste sentido, as variáveis estudadas possibilitam a confirmação da participação do ácido sulfúrico na dinâmica do sistema cárstico do Grupo Una no Estado da Bahia. / The main goal of this study is to determine the effectiveness of sulfuric acid as a corrosive agent in the karst system of the Una Group (lrecê geological basin and Salitre river basin), based on hydrochemical monitoring and the respective hydrochemical facies. The allogenic surface runoff is characterized by low ion concentrations and pH (ph=4,79 ; CV=3,15%). Sulfate is also low for this facies (\'X BARRA\'=0,57 mg/L ; CV 10,32%). With respect to the HC\'O IND. 3 POT. -\' content, the deep phreatic flux in the carbonate aquifer has the highest concentration compared to the other facies, with a mean of 359,08 mg/L. This deep phreatic flux is saturated with respect to calcite and undersaturated with respect to gypsum, showing average concentrations of 204,5 mg/L (CV 135,00%) for S\'O IND. 4 POT. 2-\', including one sampling site with average concentration of 746,07 mg/L (CV = 13,79%). Expressive sulfate concentration was also detected in the vadose seepage, with a mean of 305,09 mg/L. Underground reservoirs have high HC\'O IND. 3 POT. -\' content (\'X BARRA\'=305,10 mg/L) together with calcite saturation index close to equilibrium (S\'l IND. c\'=-0,02) and lower sulfate concentration (mean of 17,79 mg/L; CV = 52.03%). The karst springs revealed similar chemistry to the underground reservoirs, with high HC\'O IND. 3 POT. -\' content (\'X BARRA\'=246,96 mg/L ; CV = 11,0%), saturated with respect to calcite (mean of S\'l IND. c\' = 0,00; varying between 0,28 and -0,37) and mean sulfate concentration of 19,30mg/L (CV = 31.47%). The meteoric recharge has a very low solute load, with means of all ions lower than 0.5 mg/L. Stoichiometric balance calculations applied to the hydrochemical results showed that the molar balances of the various water facies do not follow the classical ratios of carbonate dissolution only due to carbonic acid, but on the contrary, they follow better the chemical system of \'H IND. 2\'S\'O IND. 4\' - CaMgC\'O IND. 3\'. The study of the expressive secondary gypsum deposits in caves, represented by crusts, stalactites and filaments, showed that their origin is related to the deep phreatic water and that the major deposition event of these deposits occurred during the water table lowering after the high water table period related to the paragenetic conduit enlargement. Isotopic composition of dissolved inorganic carbon in groundwater samples showed values of \'\'delta\' POT. 13\'CHC\'O IND. 3 POT. -\' around -10,4%o PDB-V, which are relatively enriched with respect to the predicted \'\'delta\' POT. 13\'CHC\'O IND. 3 POT. -\' of -17,1%o, if the system would be affected only by carbonic acid. This enrichment is attributed to the \'ANTPOT. 13 C\' originated by the reaction between carbonate rock and sulfuric acid. The \'delta\' POT. 34\'S of sulfate in water (\'X BARRA\'=17,7%o CDT) is slightly depleted than that of pyrite disseminated in carbonate rock (\'X BARRA\'=21,3%o), but still in the range predicted for the fractionation due to pyrite oxidation, indicating that carbonate rock is dissolved by sulfuric acid. Microbiological analysis of groundwater in the karstic aquifer revealed the presence of bacteria of the genera Acidithiobacillus and sulfate reducing bacteria (SRB). Both are typical of the sulfur cycle and produce sulfuric acid. Finally, it can be stated, based on the above described results, that sulfuric acid is an important agent in the dynamics of the studied karst.

O entorno do rio Azuis é considerada a de maior importância espeleológica do estado do Tocantins, e possui esse nome por apresentar águas cristalinas e com tons azulados. Tais características se relacionam por situar em uma área cárstica. As paisagens cársticas estão expostas, de forma direta e indireta, às diversas ações humanas, resultando em sua degradação, podendo afetar até mesmo além de seus limites. Assim, o objetivo deste trabalho é analisar a paisagem cárstica no entorno do rio Azuis, propondo reflexões sobre sua dinâmica na conjunção Físico-Social. A proposta da pesquisa visa a caracterização das feições cársticas do entorno do rio Azuis, identificando as dinâmicas na paisagem geradas pela evolução histórica da ocupação e a contextualização física do ambiente, além da produção de um mapa geomorfológico do carste com escala detalhada (1:25.000) para identificação de suas feições, buscando o entendimento das características físicas da área a partir da tríade materiais – processos – formas, além de levantar dados para um diagnóstico e gestão ambiental. Para tanto, foram realizados trabalhos de campo com o intuito de analisar e descrever a paisagem, como esta tem sido transformada pelas ações humanas e seus processos atuantes, além de aplicação de entrevistas do tipo semiestruturada aos moradores locais. Várias feições cársticas foram identificadas, expostas a várias ações humanas, comprometendo sua dinâmica natural. Foram encontrados inúmeros problemas no que diz respeito a ausência de gestão ambiental, não apenas pelo fato da presença de atividade turística, como também várias outras atividades, e com base na percepção dos moradores, a paisagem sofreu e ainda sofre inúmeras mudanças que afetam o Azuis e o sistema cárstico em geral. É necessário a execução de um Plano de Manejo que vise todos os cuidados referentes as questões ambientais amparadas na legislação ambiental, juntamente com fiscalização dos órgãos responsáveis. O mapa geomorfológico do carste proporcionou uma análise detalhada dos elementos do relevo, priorizando suas feições estruturais, o qual possibilitou descrever os processos atuantes. Portanto, mesmo sendo reduzido o recorte espacial de estudo, é uma área que apresenta grandes potencialidades espeleológica, geomorfológica e turística, além de proporcionar inúmeras possibilidades de estudo futuros no contexto da Geografia Física, não somente o município de Aurora do Tocantins, mas sim toda a região sudeste do Estado do Tocantins. / River Azuis is neighbours one of the most speleological importance area in the state of Tocantins, and this name azuis blue is reference to crystalline waters and blue tones waters. Such characteristics are related by its location in a karst area. The karst landscapes are exposed, directly and indirectly, to the various human actions, resulting in its degradation, and being able to affect even beyond its limits. Thus, the objective of this work is to analyze the karstic landscape in the surroundings of the river Azuis, proposing reflections on its dynamics in the Physical-Social conjunction. The proposal of this research is identifying the dynamics in the landscape generated by the historical evolution of the occupation and the physical contextualization of the environment, as well as the production of a geomorphological map of karst with detailed scale (1: 25,000) to identify its features, seeking to understand the physical characteristics of the area from the triad materials - processes - forms, in addition to raising data for environmental diagnosis and management. In order to do so, fieldwork was carried out to analyze and describe the landscape, as it has been transformed by human actions and its active processes, as well as the application of semi-structured interviews to local residents. Many karstic features were identified, exposed to various human actions, compromising their natural dynamics. Numerous problems were found regarding the absence of environmental management, not only due to the presence of tourist activity, but also several other activities, and based on the perception of the residents, the landscape suffered and still suffers from numerous changes that affect the Azuis and the karst system in general. It is necessary to implement a Management Plan that addresses all the care related to environmental issues covered by environmental legislation, alongside the supervision of the responsible agencies. The geomorphological map of the karst provided a detailed analysis of the elements of the relief, prioritizing its structural features, which made it possible to describe the active processes. Therefore, it is an area that presents great speleological, geomorphological and tourist potentialities, as well as providing numerous future study possibilities in the context of Physical Geography, not only the municipality of Aurora do Tocantins, but the entire southeastern region of the State of Tocantins.

As Unidades de Conservação têm finalidade de contribuir para sustentabilidade ambiental, assim, a referida pesquisa objetivou analisar a geomorfologia das feições exocársticas da APA - Área de Proteção Ambiental do município de São Desiderio – BA. Para tal, analisou-se a cartografia dos aspectos geomorfológicos estruturais e morfoesculturais, indo do 1° ao 5° táxon, através de análises cartográficas e morfométricas, servindo de base para o estudo dos elementos cársticos e análise dos fatores de degradação ambiental. A análise cartográfica dos mapas deu-se através de estudos teóricos, trabalhos de campo e georreferenciamento da carta de Angical – BA, na escala 1:100.000, (SD.23-X-A-I).Os trabalhos de laboratório foram realizados com uso do software QGIS 2.16.1. Dessa maneira, foi organizado previamente um banco de dados geográficos e cartográficos, através de arquivos vetoriais extraídos do IBGE; imagens SRTM com resolução de 30m, baixadas do TOPODATA/INPE; imagens LANDSAT 08 com a composição colorida R3G4B5, referentes à órbita 220/ponto 68 e arquivos vetoriais extraídos da base de dados CPRM e EMBRAPA. Concomitantemente, gerou-se mapas de natureza morfométrica tais como: modelo digital de elevação, hipsometria, , tipos de formas do terreno, relevo sombreado, perfis topográficos, com ênfase no estudo das características dos tipos de vertentes e densidade de drenagem. A análise dos elementos cársticos tomou como parâmetro os táxons 3°, 4° e 5° através do método de caminhamento livre conforme critérios de observação da paisagem e estudo da área pesquisada através de documentos cartográficos e posterior descrição físico-geográfica em laboratório e gabinete com auxílio de SIG e in loco com GPS e Câmera fotográfica. Essa análise foi desenvolvida através de uma abordagem pontual e qualitativa, resultando num esboço geomorfológico da área na escala 1:100.000; além de mapa exploratório de fenômenos cársticos na escala 1:100.000. Por fim, foram levantados fatores de degradação ambiental inerentes à captação hídrica em sumidouros, ressurgências, nascentes cársticas e degradação de maciços cársticos por detonações explosivas. Os resultados confirmam que a ausência de um Plano de Manejo da UC, assim como escassez de estudos científicos sobre a morfologia cárstica e sua fragilidade, contribuindo para que a paisagem estudada, apesar de compor um imensurável potencial natural, encontre-se nitidamente vulnerável às interferências danosas de natureza antrópica. / The Conservation units (UCs) has the purpose to contribute to the environmental sustainability, thus, this research aimed to analyze the geomorphology of the APA - Environmental Protection Area in the city of São Desiderio-BA. For such, the structural and morpho sculptural aspects of the geomorphological cartography were analyzed, starting from the first to the fifth taxon, through cartographic and morphometric analyzes, assisting to the basis of the study on karstic elements and analysis of environmental degradation factors. The cartographic analysis of the maps were done through theoretical studies, field woril and georeferencing of the chart of Angical - BA, in the scale 1: 100,000, (SD.23-X-A-I). The laboratorial study was carried out using the QGIS 2.16.1 software, In where the, a geographic and cartographic database were organized, using vector files extracted from IBGE institute; SRTM images with 30m resolution, downloaded from TOPODATA / INPE; Images LANDSAT 08 with the R3G4B5 color composition, referring to the orbit 220 / point 68 and vector files extracted from the database of CPRM and EMBRAPA. At the same time, maps of morphometric nature were developed such as digital elevation model, hypsometry, types of terrain forms, shaded relief, topographic profiles were generated with emphasis on the study of the characteristics of the types of slopes and density drainage. The analysis of the karst elements were taken as a parameter from the 3rd, 4th and 5th taxon, through the free walring method according to the criteria of observation of the landscape and study of the surveyed area through cartographic documents and subsequent physical and geographic description at laboratory and office as well with GIS and on-site assistance with GPS and Camera. This analysis was developed through a punctual and qualitative approach, resulting in a geomorphological outline of the area in the 1: 100,000 scale; as well as an exploratory map of karst phenomena in the 1: 100,000 scale. Finally, it were identified factors of environmental degradation, related to water supply in swallow sinks, resurgences, karst springs and degradation of karstic massifs made by explosive detonations. The results confirm that the lack of a UC Management Plan, as well as a lack of scientific studies on the karstic morphology and its fragility, contributng to the fact that the studied landscape, despite composing an immeasurable natural potential, is clearly vulnerable to the interference of an anthropic nature.

O ambiente cárstico é considerado um abrigo para a sociobiodiversidade, com presença de elementos faunísticos e da flora quase que singulares. A diversidade ecológica deste ambiente inclui uma riqueza mineral importante do ponto de vista econômico, por isso a exploração destas áreas tem crescido significativamente. Este ambiente possui ainda uma grande riqueza cultural, pois abriga elementos históricos da vida humana, através do registro rupestre no seu interior e da significativa importância religiosa. Cabe ressaltar que o ambiente cavernícola é bastante frágil e suscetível à impactos ambientais negativos. Mesmo assim, as áreas cársticas são alvos de implantação de empreendimentos altamente impactantes que podem trazer consequências irreversíveis a este ecossistema. Os empreendimentos em áreas cársticas quase sempre têm como objetivo principal a exploração dos componentes minerais presentes nas rochas carbonáticas, mas podem envolver a exploração de outros tipos de recursos naturais. Ademais, alguns empreendimentos são implementados com objetivo de utilização espacial: como a construção de rodovias, ferrovias e hidrelétricas. Desta forma, o objetivo deste estudo é a análise da implementação dos grandes empreendimentos em áreas cársticas no Tocantins, considerando os instrumentos de gestão ambiental destas áreas. Baseando-se em uma metodologia sistêmica e interdisciplinar através da análise de três empreendimentos nas três fases do licenciamento ambiental implementados em áreas cársticas. A abordagem da pesquisa foi estabelecida de acordo com a análise dos Stakeholders que compõem a gestão destas áreas: setor público, setor produtivo e sociedade civil. Os resultados advindos da pesquisa revelam que apesar dos diversos instrumentos de gestão das áreas cársticas estabelecerem uma atuação sistêmica, as constantes alterações destes levam à atuação dos órgãos e instituições de maneira fragmentada. Constatou-se também que a participação social, através da atuação dos órgãos protetivos, tem sido pontual e restritas às pesquisas acadêmico-científicas. / The karst environment is considered a shelter for the socio-biodiversity, with the presence of fauna elements and of the flora almost singular. The ecological diversity of this environment includes an important mineral richness from an economic standpoint, so the exploitation of these areas has grown significantly. This environment also has a great cultural richness, because it houses historical elements of human life, through the rock record in its interior and of significant religious importance. It is important to stress that the caveman environment is very fragile and susceptible to negative environmental impacts. Even so, karstic areas are targets for deploying highly impactful enterprises that may bring irreversible consequences to this ecosystem. The enterprises in karstic areas almost always have as main objective the exploration of the mineral components present in the carbonate rocks, but may involve the exploitation of other types of natural resources. In addition, some enterprises are implemented with the objective of spatial use: such as the construction of highways, railways and hydroelectrics. In this way, the object of this study is the analysis of the implementation of the large enterprises in karstic areas in Tocantins, considering the environmental management tools of these areas. It is based on a systemic and interdisciplinary methodology through the analysis of three enterprises in the three phases of environmental licensing implemented in karstic areas. The research approach was established in accordance with the analysis of the stakeholders that make up the management of these areas: public sector, productive sector and civil society. The results of the research show that despite the various tools of management of the karstic areas to establish a systemic action, the constant changes of these lead to the action of the organs and institutions in a fragmented way. It was also found that social participation, through the action of the protective bodies, has been punctual and restricted to academic-scientific researches.

Chemical analysis of samples collected from subsurface streams and wells were analyzed to identify nonpoint pollutants in karst aquifers resulting from agricultural land use. Major flow paths and travel times taken by nonpoint pollutants were identified. A land use limitation map showing areas where agricultural activities may results in nonpoint pollution of the karst aquifer was prepared. A groundwater susceptibility map was prepared to show areas of the karst aquifer most susceptible to groundwater contamination by nonpoint pollution resulting from agricultural land use. Research findings revealed that pollutant concentrations may reach levels thousands of times greater during high discharge events than during baseflow conditions. Approximately thirty-five percent of the drainage basin was considered to have serve limitations for conventional agricultural land use. Fifty-eight percent had moderate limitations while only seven percent had slight limitations and were considered acceptable for conventional agricultural land use. Lineaments, fracture traces and sinkholes were plotted on a map to revel those areas to the karst aquifer that are susceptible to groundwater contamination as a result of agricultural activities. Recommendations for agricultural best management practices were made in terms of reducing the potential for contributing pollutants to the karst aquifer.

abstract: Ethnogeology is the scientific study of human relationships with the Earth as a system, typically conducted within the context of a specific culture. Indigenous or historically resident people may perceive local places differently from outside observers trained in the Western tradition. Ethnogeologic knowledge includes traditional indigenous knowledge (alternatively referred to as traditional ecological knowledge or TEK), which exceeds the boundaries of non-Indigenous ideas of physical characteristics of the world, tends to be more holistic, and is culturally framed. In this ethnogeological study, I have implemented several methods of participatory rapid assessment (PRA) from the discipline of field ethnography to collect culturally framed geological knowledge, as well to measure the authenticity of the knowledge collected. I constructed a cultural consensus model (CCM) about karst as a domain of knowledge. The study area is located in the karst physiographic region of the Caribbean countries of the Dominican Republic (DR) and Puerto Rico (PR). Ethnogeological data collected and analyzed using CCM satisfied the requirements of a model where I have found statistically significance among participant’s agreement and competence values. Analysis of the competence means in the population of DR and PR results in p < 0.05 validating the methods adapted for this study. I discuss the CCM for the domain of karst (in its majority) that is shared among consultants in the countries of PR and the DR that is in the form of metaphors and other forms of culturally framed descriptions. This work continuing insufficient representation of minority groups such as Indigenous people, Native Americans, Alaska Natives, and Hispanic/Latinxs in the Earth Sciences. / Dissertation/Thesis / Doctoral Dissertation Geological Sciences 2018

The karst research community has known that traditional numerical groundwater flow codes ignore the non-Darcian, dual-permeability components of flow that can occur in karst aquifers. In this study, the potential limitations of using such tools are quantified by evaluating the relative performances of 3 groundwater flow models at a test-site near Weeki Wachee, Florida, in the dual-permeability Upper Floridan aquifer. MODFLOW-2005 and MODFLOW-2005 Conduit Flow Process (CFP), a Darcian/non-Darcian, dual-permeability groundwater flow code recently developed by the U.S. Geological Survey, are used in this study. A monitoring program consisting of discharge measurements and high frequency data from 2 springs and monitoring wells penetrating the matrix and conduit networks of a karst aquifer was initiated to characterize the test-site and constrain new parameters introduced with MODFLOW-2005 CFP. The monitoring program spanned conditions prior to, during, and following convective and tropical storm activity, and a drought. Analytical estimates for Reynolds numbers, ranging from 105 to 106, suggest that turbulent flow occurs in portions of the underlying conduit network. The direction and magnitude of fluid exchange observed between the matrix and conduit network indicate the conduit network underlying the test-site drains the matrix. Head differences and observed responses in monitoring wells penetrating the matrix and conduit network indicate that the hydraulic conductivities between the 2 networks do not significantly differ from each other. A conceptual model for the spatial distribution of preferential flow pathways using multiple data types, including shallow recession limbs observed in discharge hydrographs indicate a slow responding aquifer with a high storage capacity, and a poorly integrated conduit drainage network with little to no point recharge. Model performances were evaluated by comparing observed hydrographs for discharge and monitoring wells penetrating the matrix and conduit network following convective and tropical storm events, and drought conditions, to simulated values from transient simulations. Model statistics for 32 target wells and sensitivity analysis were included in the evaluation. The dual-permeability model using the MODFLOW-2005 CFP Mode 1 displayed the highest performance with improved matches ranging from 12 to 40% between simulated and observed discharges relative to the laminar and laminar/turbulent equivalent-continuum models.

Seepage is an important component of the water budget in closed basins that do not have surface water drainage features. In the shallow water table environment of Florida, internal drainage of soil controls flooding. With the recent rapid population growth and urban development in the state, a simple, field-based method is needed to estimate seepage rates. In this study five locations in Hillsborough County, Florida, were instrumented with wells with pressure transducers measuring water level fluctuations at 1 minute resolution. For closed basins with lakes, evaporation (E) rates were determined using data from a weather station and Penman-Monteith FAO56 method, and then seepage rates were calculated from a water budget. Seepage rates varied greatly depending on conditions specific to the site. The seepage rates found for the three surface water sites in this study were 1.1 cm/d for a retention pond surrounded with dense vegetation, 0.5-0.8 cm/d for a natural lake located close to a groundwater pumping site, and 0.4 cm/d for another natural lake with no groundwater pumping in the proximity. Two methods to estimate seepage rates into semi-confined aquifers were compared: (a) mass balance approach and (b) Darcy's equation. At one of the sites the rate was 0.1 cm/d, and at the other site (sinkhole) it ranged between 0.8 cm/d during the wet season and 0.2 cm/d during the dry season when the head difference between the surficial and Floridan aquifers became smaller. The results of the study indicate that simple and relatively inexpensive field methods can estimate seepage within a narrow range and give reasonable seepage predictions that can be used in flood modeling. The obtained values indicate that seepage does not provide adequate drainage relief in closed basins. Another important finding is the magnitude of the local recharge to the Floridan aquifer. Further sensitivity studies on hydrological models that use seepage as one of the inputs may indicate that lower data collection resolution or simpler ET estimation methods are acceptable.

Bowling Green, Kentucky is located in a distinctive karst region, characterized by subsurface drainage. The Lost River is a large subsurface stream which flows beneath the city. It receives much of the stormwater runoff from Bowling Green, since most of the city's runoff is directed underground. Significant pollutants in Bowling Green's stormwater runoff were identified from water quality test results of storm event grab samples, and a composite sample, of runoff entering the urban By-Pass Cave. Water quality test results were also obtained from storm event grab samples, and a composite sample, of the Lost River at the Blue Hole before it reached Bowling Green and at the Resurgence after it had passed beneath Bowling Green. Significant pollutant test results from the Blue Hole and Resurgence were analyzed to determine the impact of urban stormwater runoff on the water quality of the Lost River. Suspended solids were the only urban runoff pollutant identified as entering the Lost River in significant quantities. Animal waste, iron, and oil and grease were identified as stormwater runoff pollutants of the Lost River, but whose origin, either urban or rural, could not be conclusively determined from the available data.