We estimated the potential groundwater recharge (Rpot) of a drywell that receives, temporarily stores, and infiltrates direct surface runoff from a contribution area (180.5 m2) comprising a roof and a cemented floor. The Rpot for traditional rainwater management and for similar contribution area but covered with grass was also estimated for comparison. Our methodology involved the use of water budget equation, monitoring of rainfall and soil water content up to 1.92 m depth, estimation of drywell overflow using the modified Puls model, and determination of actual evapotranspiration using water stress coefficient in 2017 and 2018. Results revealed that the Rpot for drywell was 83.3% of the precipitated volume, 2.22 times higher than that of the grass-covered area (37.6%) given the increased area for evapotranspiration in the latter. In turn, the traditional urban drainage system did not demonstrate potential of groundwater recharge. Therefore, the drywell contributes significantly to groundwater recharge apart from serving as local flood control.

The efficiency and suitability of different models to estimate infiltration rates in Ferralic Arenosols and Rhodic Ferralsols in southern Brazil are evaluated in this paper. The influence of nine types of land use and soil management practices on infiltration modeling is also assessed. Model parameterization was performed fitting 42 experimental infiltration curves obtained by in situ tests with a double-ring infiltrometer. Soil characterization was also performed in laboratory. The results were assessed using basic statistical descriptors and model accuracy indicators (Nash and Sutcliffe efficiency coefficient and root mean square error). The investigated models satisfactorily simulated the infiltration rates and the most accurate model was modified Kostiakov, followed by the Horton; Singh and Yu; modified Holtan; Holtan; Philip; Green and Ampt/Mein and Larson and Kostiakov. Different types of land uses and soil management practices significantly affect the infiltration rates, mainly those combination with great presence of macroporosity that resulted in an erratic infiltration behavior and affected the infiltration model accuracy.

This paper presents a procedure to study depressional wetlands in southern Brazil and focuses on the mechanisms controlling water dynamics and environmental degradation due to anthropogenic interference. The study is based on an inventory of wetlands, a digital elevation model, the geological and geotechnical characteristics of geological materials, a multitemporal analysis of satellite images, the distribution of land use types, and onsite monitoring of water level and rainfall data. One hundred and twelve depressional wetlands were identified with a total area of 902 ha and a catchment area of 5456.8 ha. These wetlands were grouped into two classes with different hydrological control mechanisms. From the water level monitoring, the wetlands were found to present different hydrological conditions. Before rainy periods, the wetlands were almost dry or had little water; after rainy periods, over half of the wetlands were still dry or had groundwater levels below the surface, and the water levels of the other wetlands increased. The multitemporal analysis showed a reduction in the wetland water surface area from 270 ha in 1991 to 60 ha in 2019, which confirms the monitoring result that the amount of stored water is decreasing because of anthropogenic activities. Anthropogenic activities affect wetland water dynamics because of changes in the landscape and soil characteristics of the catchment area, and drainage of wetland areas by ditches for agricultural water supply; more than 50% of wetlands showed a high degree of change (environmental degradation), with conditions that make restoration or remediation very difficult.

The objective of this study was to propose a set of procedures to assess areas regarding the suitability of sustainable drainage systems (SuDSs) with application in a basin in the urban area of São Carlos (Brazil). The assessment was based on an analysis of 39 attributes reflecting the infiltration conditions that control the functional and constructive aspects of the systems, including subsurface drainability, stability, and groundwater contamination potential, which control the degree of suitability of each plot of land. The data obtained through engineering geological mapping procedures and physical principles were used to characterize the area, which resulted in the division of the basin into five SuDS suitability zones, ranging from favorable to restrictive. The proposed procedures proved to be efficient for analyzing the suitability of different SuDS types and the zoning of an area into terrain units. This approach can help planners identify the most appropriate SuDS types for a given unit, optimize the efficiency/cost relationship, and foresee potential environmental and construction-related challenges. In other words, this procedure enables the assessment of the suitability of SuDSs for different unit terrain types with inexpensive and environmentally efficient technological procedures and resources and can be applied at a fine geographic scale.

Este trabalho apresenta os resultados obtidos com a aplicação de um conjunto de procedimentos propostos para avaliação de áreas com base em dados obtidos por meio de princípios e métodos de mapeamento geotécnico para a adequabilidade de Sistemas de Drenagem Sustentáveis (SDSs). A aplicação foi desenvolvida na bacia do córrego do Gregório, na área urbana da cidade de São Carlos-SP, com uma extensão de 19km², visto a ocorrência freqüente de inundações com perdas econômicas e sociais significativas em decorrência das mudanças dos componentes ambientais impostas pelos processos de urbanização. A avaliação foi baseada na divisão inicial da área em vertentes e na análise frente a 39 atributos pertinentes ao relevo, águas, materiais inconsolidados, substrato rochoso, eventos perigosos potenciais, aspectos antropogênicos e zonas de proteção. Os atributos estão associados às condições de infiltração que controlam a funcionabilidade e as construtivas dos sistemas, de drenabilidade subsuperficial, de estabilidade e do potencial de contaminação das águas subterrâneas, as quais controlam o grau de adequabilidade de cada parcela de terreno. Os dados obtidos por meio de procedimentos e princípios do mapeamento geotécnico permitiram a caracterização em termos de aspectos envolvidos, o que resultou na divisão da bacia em 5 zonas de adequabilidade aos SDSs. Cerca de 60% da bacia apresenta características dos componentes ambientais que propiciam diferentes graus de adequabilidade para tipos de sistemas baseados na infiltração (Zonas 1, 2 e 3), enquanto 25% apresentam condições mais restritivas e com potencial para a instalação de sistemas de coleta e acúmulos para controle do fluxo do escoamento superficial (Zona 4) e cerca de 15% com restrições que não indicam o uso destes recursos de drenagem. Os resultados obtidos vêm ao encontro da idéia de que é possível a adoção desses sistemas e, como conseqüência, o controle do processo de inundação com recursos tecnológicos de baixo custo e ambientalmente eficientes.