Colombia es un país con amplia riqueza en recursos hídricos subterráneos que se encuentra en medio de un desarrollo socioeconómico, donde la ejecución de proyectos interviene en el ambiente, por tanto se requiere establecer medidas que favorezcan la preservación de los recursos y a su vez la evolución y el crecimiento económico del país. Es por ello, que surge la necesidad de implementar protocolos que evalúan parámetros y variables para identificar áreas o elementos primordiales en la naturaleza, como es el caso específico de los manantiales. Estas surgencias de agua que se generan de forma natural y como consecuencia de la descarga de flujos subterráneos, son de alta importancia, dado que proveen un recurso vital al ser humano. La identificación errónea de estos puntos puede ocasionar daños irreparables a la naturaleza o al desarrollo de la sociedad, por tanto, se propone el presente protocolo donde se recomienda evaluar aspectos topográficos, geológicos, geomorfológicos, hidrogeológicos, hidroquímicos, climatológicos y de cobertura vegetal que integrados generan la evaluación de las condiciones reales de las surgencias y de esta forma se determina si es o no un punto de descarga de agua subterránea denominado manantial. La implementación de esta herramienta origina que el análisis de la información de un área donde se evidencia presencia de agua en superficie, sea interpretada de forma eficiente de tal forma que se obtiene una correcta aplicación de la normatividad colombiana, el desarrollo óptimo de planes sociales o económicos y primordialmente se establece una protección certera a los manantiales. | Resumen Introducción Materiales y métodos Resultados y discusión Conclusiones Referencias bibliográficas | Colombia is a development country which has a lot of groundwater resources where implementations of some projects could be affect the environment. Therefore, it is necessity to establish protocols that preserve these resources and at the same time, these help the economy growth based on parameters and variables to identify which areas or corcern things are fundamental in the nature as well as springs. These upwellings which form in a natural way and they generate as a consequence of groundwater flow are very important due to bring a vital resource of population. The misdentification in these spots could cause nature irreparable damage or problems of society development. Hence, this protocol recommends to evaluate topographic , geological, geomorphological, hydrogeological, hydrochemical, climatological and land cover aspects that generate real upwelling conditions to determinate whether or not a spot is a groundwater discharge site called Spring. Analysis information of specific area that evidence presence of water using this tool could be interpreted in an efficient way to obtain a better understanding to apply Colombian regulations as well as social or economic optimal programs development and mainly, an accurate protection of Springs.

Experimentos foram conduzidos em um Latossolo Vermelho-Escuro distrofico, textura argilosa (LEd), em Sete Lagoas, MG. Os tratamentos consistiram de quatro niveis de nitrogenio aplicado em cobertura (0,50, 100e 200 kg/ha de N), combinados com laminas de agua obtidas atraves do sistema "line source", que fornece um padrao de distribuicao decrescente de agua a medida que se afasta da linha de irrigacao. Irrigou-se todas as vezes que a tensao de agua no solo, entre as duas fileiras de milho proxima a linha de irrigacao, atingiu valores entre -0,6 e -0,7 bars, com o controle feito atraves de tensiometro. Todos os tratamentos receberam a mesma adubacao no sulco por ocasiao do plantio, apos cada cultivo. Utilizou-se a cultivar BR 201, no espacamento de 0,90 entre linhas e densidade de 60.000 plantas/ha. Os dados apresentados sao de experimentos conduzidos nos invernos de 1988, 1989 e 1990. Nao houve resposta a adubacao nitrogenada em cobertura nos dois primeiros cultivos. As produtividade maximas estimadas, com ou sem adubacao nitrogenadas em cobertura, foram de 7.860 e 7.580 kg/ha para os anos de 1988 e 1989, respectivamente, o que demonstra uma boa capacidade de suprimento de nitrogenio pelo solo nesses dois cultivos. Entretanto, a resposta a adubacao nitrogenada em cobertura aumentou rapidamente apos cada cultivo. Apos quatro cultivos sucessivos na mesma area, a produtividade caiu drasticamente, de 7.860 kg/ha, em 1988, para 4.350 kg/ha, em 1990.

Despite the key role of water in livestock growth and reproduction, there is little information on water quality for Mexicos beef cattle ranches. The objective of this study was to evaluate drinking water quality for beef cattle in the cow-calf operation through calculation of a water quality index (WQI) that relates water physical-chemical composition with common cattle drinking water sources. The study was conducted in 25 cattle ranches of the cow-calf system in seven municipalities of Chihuahua, Mexico. In all cattle ranches, water samples were collected from the main water sources, and physical and chemical parameters were analyzed. Statistical analyses were done through Kruskal-Wallis test, considering water sources (WS) as a source of variation. The WQI was calculated considering the parameters closely related to animal health and productivity and following standard procedures. Most parameters showed high variation among WS. The only parameters inuenced by WS were pH, As (p < 0.05) and Co (p < 0.01). The parameters that surpassed the optimum level for cattle drinking were turbidity for all WS and Mn for earthen tank and spring/river water. Groundwater showed the best quality with a 50.34 WQI, corresponding to good class. Earthen tank water also corresponded to good class with a 98.8 WQI, while spring/river water was classied as poor water for cattle with a 114.47 WQI

O experimento foi conduzido em um Latossolo Vermelho-Escuro, alico textura argilosa, em Sete Lagoas, utilizando a cultivar BR 201, plantada em 25/03/88 e colhida em 05/09/88. As irrigacoes foram realizadas por aspersores setoriais, em parcelas de 12 x 12cm, de acordo com a indicacao de tensiometros e blocos de gesso instalados a 20cm de profundidade. A lamina de agua aplicada foi medida por quatro coletores instalados no centro de cada parcela e as chuvas foram medidas atraves de um pluviometro instalado proximo ao experimento. No calculo do consumo de agua pela cultura, somaram as irrigacoes, as chuvas e a variacao de unidade do solo ate 1m de profundidade, no inicio e no final do ciclo da cultura. O consumo de agua dos tratamentos irrigados quando a tensao de agua no solo atingiu -0,7, -3,0 e -10,0 atm, acumulado ao longo do ciclo da cultura, foi comparado com a necessidade de agua estimado pelos metodos de Penmam e Tanque Classe A. Nao houve diferenca entre as curvas de consumo e necessidade de agua, acumulando ao longo do ciclo da cultura, indicando que o metodo do tanque Classe A podera ser utilizado para estimar a necessidade de agua da cultura do milho, consumo dos coeficientes de tanque e de cultura, segundo Doorenbos e Prutt(1977). Esse metodo apresenta, como vantagem, a facilidade de obtencao de dados de evaporacao de periodos passados e a possibilidade de instalacao do Tanque Classe A junto a cultura, permitindo estimar a necessidade de agua ao longo de todo ciclo vegetativo.

O presente estudo teve por objetivo a realização de um levantamento das características físicas, químicas e físico-químicas das águas subterrâneas da Bacia Sedimentar do Rio Parnaíba, em especial aquelas características relevantes para a determinação da qualidade dessas águas para fins de irrigação. Foram coletadas amostras de água em 270 poços georreferenciados localizados em 14 municípios da Microrregião de Teresina-PI. As amostras foram coletadas em duas épocas distintas, ou seja, nas estações secas de 2004 e de 2005. Nessas amostras foram realizadas determinações dos seguintes parâmetros: pH, NH4+, NO3-, Ca2+, Mg2+, CE, RAS, Na+, Cloretos, Bicarbonatos e Carbonatos. Os resultados foram interpolados em um SIG (Sistemas de Informações Geográficas) – SPRING – com o objetivo de constituir mapas temáticos mostrando as classes de restrição das águas para fins de irrigação. Dentre os resultados obtidos, a análise conjunta de RAS e CE revelou potenciais problemas de infiltração da água no solo em mais da metade dos municípios, mostrando a necessidade de um manejo adequado da irrigação com vistas a mitigar os problemas nessas áreas.

Stable isotopes (δ¹⁸O, δD), dissolved silica (DSi) concentration and major ion composition were used to indicate groundwater/surface-water interaction between the aquifers, the rivers and a lake in the high-latitude Lake Pyhäjärvi catchment in Finland. Significant differences were recorded in water chemistry between the groundwater and surface waters, especially in the stable isotope composition and DSi concentrations, which could thus be used as tracers. The baseline data on isotopic patterns and hydrogeochemistry in the hydrological cycle were provided by a 1-year monitoring survey in this snow-type catchment area. The proportions of groundwater in the rivers, the lake inshore area and in a groundwater abstraction plant were calculated using stable isotopes and DSi. Two inflowing rivers had distinct differences in their water chemistry. DSi has potential as a tracer in the river environment, whereas stable isotopes were more applicable in the lake environment. Locally, near the shoreline, the effect of discharging groundwater on the lake-water quality could clearly be observed. Furthermore, infiltration of the lake water into the aquifer could be observed near the pumping wells onshore. This infiltration presents a potential risk for the water quality of water supply (intake) wells. Frequent sampling is needed as part of the evaluation of the level of groundwater/surface-water interaction in snow-type catchments in order to estimate the magnitude of seasonal variation. In groundwater/surface-water interaction studies, spring thaw and high-precipitation events could be problematic, in terms of both sampling and interpreting results.

Freshwater scarcity is an ever-increasing problem throughout the arid and semi-arid countries, and it often results in poverty. Thus, it is necessary to enhance understanding of freshwater resources availability, particularly for groundwater, and to be able to implement functional water resources plans. This study introduces a novel statistical approach combined with a data-mining ensemble model, through implementing evidential belief function and boosted regression tree (EBF-BRT) algorithms for groundwater potential mapping of the Lordegan aquifer in central Iran. To do so, spring locations are determined and partitioned into two groups for training and validating the individual and ensemble methods. In the next step, 12 groundwater-conditioning factors (GCFs), including topographical and hydrogeological factors, are prepared for the modeling process. The mentioned factors are employed in the application of the EBF model. Then, the EBF values of the GCFs are implemented as input to the BRT algorithm. The results of the modeling process are plotted to produce spring (groundwater) potential maps. To verify the results, the receiver operating characteristics (ROC) test is applied to the model’s output. The findings of the test indicated that the areas under the ROC curves are 75 and 82% for the EBF and EBF-BRT models, respectively. Therefore, it can be inferred that the combination of the two techniques could increase the efficacy of these methods in groundwater potential mapping.

Among the advances made in analytical and numerical analysis methods to quantify groundwater/surface-water interaction, one methodology that stands out is the use of heat as an environmental tracer. A large data set of river and riverbed temperature profiles from the Aa River in Belgium has been used to examine the spatial-temporal variations of groundwater/surface-water interaction. Exchange fluxes were calculated with the numerical heat-transport code STRIVE. The code was applied in transient mode to overcome previous limitations of steady-state analysis, and allowed for the calculation of model quality. In autumn and winter the mean exchange fluxes reached −90 mm d⁻¹, while in spring and early summer fluxes were −42 mm d⁻¹. Predominantly gaining conditions occurred along the river reach; however, in a few areas the direction of flow changed in time. The river banks showed elevated fluxes up to a factor of 3 compared to the center of the river. Higher fluxes were detected in the upstream section of the reach. Due to the influence of exchange fluxes along the river banks, larger temporal variations were found in the downstream section. The exchange fluxes at the river banks seemed more driven by variable local exchange flows, while the center of the river was dominated by deep and steady regional groundwater flows. These spatial and temporal differences in groundwater/surface-water exchange show the importance of long-term investigations on the driving forces of hyporheic processes across different scales.

Three-dimensional geological and groundwater flow models of a submarine groundwater discharge (SGD) site at Hanko (Finland), in the northern Baltic Sea, have been developed to provide a geological framework and a tool for the estimation of SGD rates into the coastal sea. The dataset used consists of gravimetric, ground-penetrating radar and shallow seismic surveys, drill logs, groundwater level monitoring data, field observations, and a LiDAR digital elevation model. The geological model is constrained by the local geometry of late Pleistocene and Holocene deposits, including till, glacial coarse-grained and fine-grained sediments, post-glacial mud, and coarse-grained littoral and aeolian deposits. The coarse-grained aquifer sediments form a shallow shore platform that extends approximately 100–250 m offshore, where the unit slopes steeply seawards and becomes covered by glacial and post-glacial muds. Groundwater flow preferentially takes place in channel-fill outwash coarse-grained sediments and sand and gravel interbeds that provide conduits of higher hydraulic conductivity, and have led to the formation of pockmarks on the seafloor in areas of thin or absent mud cover. The groundwater flow model estimated the average SGD rate per square meter of the seafloor at 0.22 cm day⁻¹ in autumn 2017. The average SGD rate increased to 0.28 cm day⁻¹ as a response to an approximately 30% increase in recharge in spring 2020. Sensitivity analysis shows that recharge has a larger influence on SGD rate compared with aquifer hydraulic conductivity and the seafloor conductance. An increase in recharge in this region will cause more SGD into the Baltic Sea.