The potential of karst aquifers as a drinking water resource is substantial because of their large storage capacity gained in the course of carbonate dissolution. Carbonate dissolution and consequent development of preferential paths are also the reasons for the complex behavior of these aquifers as regards surface and underground flow. Hydrological modeling is therefore of paramount importance for an adequate assessment of flow components in catchments shaped on karsts. The cross tabulation of such components with geology, soils, and land use data in Geographic Information Systems helps decision makers to set up sustainable groundwater abstractions and allocate areas for storage of quality surface water, in the context of conjunctive water resources management. In the present study, a hydrologic modeling using the JAMS J2000 software was conducted in a karst area of Jequitiba River basin located near the Sete Lagoas town in the state of Minas Gerais, Brazil. The results revealed a very high surface water component explained by urbanization of Sete Lagoas, which hampers the recharge of 7.9 hm³ yr⁻¹ of storm water. They also exposed a very large negative difference (−8.3 hm³ yr⁻¹) between groundwater availability (6.3 hm³ yr⁻¹) and current groundwater abstraction from the karst aquifer (14.6 hm³ yr⁻¹), which is in keeping with previously reported water table declines around drilled wells that can reach 48 m in old wells used for public water supply. Artificial recharge of excess surface flow is not recommended within the urban areas, given the high risk of groundwater contamination with metals and hydrocarbons potentially transported in storm water, as well as development of suffosional sinkholes as a consequence of concentrated storm flow. The surface component could however be stored in small dams in forested areas from the catchment headwaters and diverted to the urban area to complement the drinking water supply. The percolation in soil was estimated to be high in areas used for agriculture and pastures. The implementation of correct fertilizing, management, and irrigation practices are considered crucial to attenuate potential contamination of groundwater and suffosional sinkhole development in these areas.

The zoning of groundwater recharge potential would be attractive for water managers, but is lacking in many regions around the planet, including in the Jequitiba River basin, Minas Gerais, Brazil. In this study, a physically based spatially distributed method to evaluate groundwater recharge potential at catchment scale was developed and tested in the aforementioned Jequitiba River basin. The data for the test was compiled from institutional sources and implemented in a Geographic Information System. It comprised meteorological, hydrometric, relief, land use, and soil data. The average results resembled the annual recharge calculated by a hydrograph method, which worked as validation method. The spatial variation of recharge highlighted the predominant contribution of flat areas, porous aquifers, and forested regions to groundwater recharge. They also exposed the negative effect of urbanization. In combination, these factors elected the following sectors of the Jequitiba River basin as regions of high recharge potential: the south-southeast part of the headwaters in Prudente de Morais; Sete Lagoas towards the central part of the basin; and the region between Funilândia and Jequitiba, near the Jequitiba river mouth. Some management practices were suggested to improve groundwater recharge. The map of groundwater recharge potential produced in this study is valuable and is therefore proposed as tool for planners in the sustainable use of groundwater and protection of recharge areas.

Headwater catchments store valuable resources of quality water, but their hydraulic response is difficult to assess (model) because they are usually deprived of monitoring stations, namely hydrometric stations. This issue becomes even more pertinent because headwater catchments are ideal for the practice of conjunctive water resources management involving the supply of towns with groundwater and surface water, a solution that can be used to mitigate overexploitation of groundwater resources in densely urbanized and populated areas. In this study, a stepwise approach is presented whereby, in a first stage, a gauged basin was modeled for stream flow using the JAMS J2000 framework, with the purpose to obtain calibrated hydraulic parameters and ecological simulated stream flow records. Having validated the model through a comparison of simulated and measured flows, the simulated record was adjusted to the scale of an ungauged sub-basin, based on a new run of JAMS J2000 using the same hydraulic parameters. At this stage, a second validation of modeled data was accomplished through comparison of the downscaled flow rates with discharge rates assessed by field measurements of flow velocity and water column height. The modeled basin was a portion of Jequitiba River basin, while the enclosed sub-basin was the Marinheiro catchment (state of Minas Gerais, Brazil). The latter is a peri-urban watershed located in the vicinity of Sete Lagoas town, a densely urbanized and populated area. This town uses 15.5 hm³ year⁻¹ of karst groundwater for public water supply, but the renewable resources were estimated to be 6.3 hm³ year⁻¹. The impairment between abstraction and renewable resources lasts for decades, and for that reason the town experiences systemic water table declines and sinkhole development. The present study claims that the storage of quality water in the Marinheiro catchment, in a dam reservoir, would help alleviate the depletion of groundwater resources in the karst aquifer because this catchment could deliver 4.73 hm³ year⁻¹ of quality surface water to the municipality without endangering ecologic flows. The construction of a small dam at the outlet of Marinheiro catchment could also improve aquifer recharge. Presently, the annual recharge in this catchment approaches 1.47 hm³ but could be much larger if the small dam was installed in the water course and the captured stream water managed properly.

A bacia hidrográfica do Rio dos Sinos concentra uma intensa atividade agrícola e industrial em seu território, o que ao longo dos anos tem provocado um desequilíbrio ambiental e um comprometimento dos seus recursos naturais. Entendendo a bacia como uma unidade de gestão territorial, se faz necessário o aprimoramento e a criação de ferramentas que auxiliem na gestão deste território. Neste sentido, o presente artigo tem como objetivo a aplicação de uma metodologia de zoneamento ambiental, denominada Potencial de Uso Conservacionista (PUC), com fins de estratificar o território da bacia em níveis de potencial natural de uso. Para isso, foram utilizadas bases geoespaciais de solo, litologia e declividade da região, como dados de entrada deste modelo, determinando pesos para essas variáveis, através de uma Análise Hierárquica de Processos (AHP). A partir disto, foram obtidos os níveis de PUC da bacia do Rio dos Sinos, que foram combinados com um mapa de uso e cobertura do solo da região para um diagnóstico dos níveis de conservação da área. Os resultados mostraram que na bacia predominam os níveis de potencial de uso entre “Médio” e “Alto”. A bacia apresenta certo nível de conservação em seu uso do solo no alto curso, o que combina com os níveis “Baixo” e “Muito Baixo” de PUC ali presentes. O desafio principal reside na necessidade de adequação das atividades agrícolas e indústrias no médio e baixo curso da referida bacia, onde se encontram os níveis de potencial de uso “Alto” e “Muito Alto”, a fim de promover o uso sustentável dos recursos ambientais ali presentes e a mitigação dos impactos ambientais destas atividades.

As Áreas de Preservação Permanente (APP) são porções territoriais protegidas por Lei federal (Lei 12.651/2012) que apresentam funções ambientais fundamentais para a conservação dos recursos hídricos e para a proteção do solo.O objetivo do presente estudo foi caracterizar e diagnosticar os conflitos de uso e de ocupação do solo nas APP de curso d’água na bacia do córrego Marinheiro, Sete Lagoas - MG, comparando resultados obtidos pelo cálculo de NDVI em imagens dos satélites Landsat 8 e Ikonos-II. O método foi desenvolvido em seis etapas principais, quais sejam: i) Préprocessamento das imagens; ii) Cálculo de NDVI; iii) Obtenção da rede de drenagem; iv) Cálculo das Classes de NDVI das Áreas de Preservação Permanente (APP); e v) Caracterização e análise das APP; e vi) Validação em campo. Os resultados obtidos permitiram identificar a presença de cinco classes de NDVI. Foi possível concluir que: (1) nas APP de curso d’água a vegetação senescente foi a classe de maior predomínio, de acordo com os cálculos realizados com as cenas do Landsat 8 (51,6%), nas cenas do satélite Ikonos-II o predomínio foi da classe Pastagens (51,2%); (2) pela classificação do NDVI das imagens Ikonos-II, observou-se uma boa precisão e melhores resultados, comparando-se com o satélite Landsat 8, principalmente devido à resolução espacial das imagens multiespectrais ser de 4 metros.