This study analyses the effect of climate change on water quality in the Júcar River Basin from future estimations of hydrological inputs and water temperature (WT). For this purpose, a large-scale water quality model was used to estimate the ecological status of all the water bodies, based on the concentrations of BDO5, P, NH4+ and NO3– for the future horizons 2020, 2050 and 2080. In this study, a greater number of water bodies with higher pollution levels (80-100% failures) were obtained in the horizons 2050 and 2080, which are located in the middle and lower parts of the basin. In addition, the degradation of BDO5 and the NH4+ is highly dependent on WT, highlighting the importance of considering this variable in the model. | En este estudio se analiza el efecto del cambio climático en la calidad del agua de la cuenca del Júcar a partir de estimaciones futuras de aportaciones hidrológicas y temperatura del agua (Ta). Para ello, se utilizó un modelo de calidad de aguas a escala de cuenca con el que se estimó el estado ecológico de todas las masas de agua, basándose en las concentraciones de DBO5, P, NH4+ y NO3- para los horizontes futuros 2020, 2050 y 2080. De este análisis se obtuvo un incremento del número de masas con altos niveles de contaminación (80-100% incumplimientos) en los horizontes 2050 y 2080, localizadas sobre todo en la parte media y baja de la cuenca. Además, la degradación de la DBO5 y el NH4+ es muy dependiente de la temperatura del agua, poniendo de manifiesto la importancia de considerar esta variable en el modelo.

This work aimed to evaluate the preference and water consumption of native goats in the semiarid of Brazil. The water was freely supplied, in individual buckets, one exposed to the sun and the other in the shade. The experiment was realized using 18 animals of Moxotó, Graúna and Azul breeds, with average weight of 16,6 ± 2,4 kg, kept in confinement in individual stalls equipped with feeders and drinkers, during the period from January to February of 2009. The water temperature was measured by sensors (thermocouples type T - copper/constantan), which were coupled to a system of data acquisition. It was observed that the average water temperature exposed to the sun was 29.02 ºC, and 23.85 ºC in the shade. For all breeds there was a preference for the water exposed to the sun, corresponding to an average consumption of 64.71% of the total. Among the breeds, the greatest preference for water exposed to the sun was the Azul (71.18%), followed by the Moxotó (65.95%) and the Graúna (57.00%). The animals consumed more water during the day, and the average water consumption was 1.15 grams day-1, corresponding to 6.9 % of body weight of the animals.<br>O trabalho teve o objetivo de avaliar a preferência e o consumo de água por caprinos nativos no semiárido brasileiro, fornecida à vontade, em baldes individuais, sendo um exposto ao sol e outro à sombra. O experimento foi realizado, utilizado-se de 18 animais das raça Moxotó, Graúna e Azul, com peso vivo médio de 16,6 ± 2,4 kg, mantidos em confinamento, em baias individuais, providas de comedouro e bebedouro, durante o período de janeiro a março de 2009. A temperatura da água foi medida através de sensores (termopares tipo T - cobre/constantan), que estavam acoplados a um sistema de aquisição de dados. Observou-se que a temperatura média da água exposta ao sol foi de 29,02 ºC, e à sombra, de 23,85 ºC. Para todas as raças, houve preferência pela água exposta ao sol, correspondendo a um consumo médio de 64,71% do total. Entre as raças, a maior preferência pela água exposta ao sol foi da Azul (71,18%), seguida da Moxotó (65,95%) e Graúna (57,00%). Os animais consumiram mais água no período diurno, sendo o consumo médio de 1.150 gramas dia-1, correspondendo a 6,9% do peso vivo dos animais.

Surface-water/groundwater exchange through the evaluation of riparian-zone temperature data has attracted increasing attention in recent years. The Fox Ditch Canal, Nevada, USA, was chosen for this study on seasonal variations of riparian-zone water exchange. Groundwater temperature and hydraulic head real-time monitoring data were collected from March to November 2012. A calibrated hydro-thermal coupling model was used to characterize the riparian-zone temporal and spatial temperature distribution, thereby providing a standard against which the performances of four analytical solution models for calculated riparian-zone vertical seepage velocity could be assessed. The results indicated that the proposed model provided a simulation that was able to represent dynamic changes in riparian-zone soil temperature. Although small variations in patterns and magnitudes of riparian-zone water exchange were evident at a daily scale, they varied significantly over a seasonal scale. Comparison of the results of the four analytical solutions and numerical computation found that the Hatch solution by the amplitude method provided the highest accuracy for calculating groundwater velocity in this area (2.47 × 10⁻⁶ to 3.15 × 10⁻⁶ m/s). Global sensitivity analysis of hydro-thermal coupling model parameters showed that porosity had the most significant impact on temperature in the model.

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To investigate the effect of recharge water temperature on bioclogging processes and mechanisms during seasonal managed aquifer recharge (MAR), two groups of laboratory percolation experiments were conducted: a winter test and a summer test. The temperatures were controlled at ~5±2 and ~15±3 °C, and the tests involved bacterial inoculums acquired from well water during March 2014 and August 2015, for the winter and summer tests, respectively. The results indicated that the sand columns clogged ~10 times faster in the summer test due to a 10-fold larger bacterial growth rate. The maximum concentrations of total extracellular polymeric substances (EPS) in the winter test were approximately twice those in the summer test, primarily caused by a ~200 μg/g sand increase of both loosely bound EPS (LB-EPS) and tightly bound EPS (TB-EPS). In the first half of the experimental period, the accumulation of bacteria cells and EPS production induced rapid bioclogging in both the winter and summer tests. Afterward, increasing bacterial growth dominated the bioclogging in the summer test, while the accumulation of LB-EPS led to further bioclogging in the winter test. The biological analysis determined that the dominant bacteria in experiments for both seasons were different and the bacterial community diversity was ~50% higher in the winter test than that for summer. The seasonal inoculums could lead to differences in the bacterial community structure and diversity, while recharge water temperature was considered to be a major factor influencing the bacterial growth rate and metabolism behavior during the seasonal bioclogging process.

Abstract: This paper describes a method to expand an annual series of water daily temperature to a larger period of time. Data collected for nearly a year by an automatic environmental system (SIMA) at high frequency in time were used to study the relationships of maximum and minimum temperatures of the air with the daily average, as well as the relationship between them and the temperature of water two meters deep. We also found a weather station near and alike and which had a long-term data of air temperature. By means of statistical calculations, we first expanded air temperatures series and subsequently water temperatures for the same period were obtained. Temperature intervals were established respecting the comfort level for the production of fish in the reservoir. The frequency of occurrence of the water temperature at each interval was estimated. The combination of high-frequency data, a series of long-term data, and statistical tools has shown promise. The results indicate that temperatures of the water in the reservoir Furnas remain between 20 and 27°C most of the time and are suitable for the creation of Nile tilapia.

In carbonate massifs, flow patterns are conditioned by karstification processes which develop a conduit network and preserve low permeability microfractured blocks. The Sierra de las Nieves karst massif (southern Spain) is subjected to a given climatic and geological context, and thus it is possible to analyse the spatial and temporal variability of the water temperature and electrical conductivity at its main karst outlets, which display different responses to rainfall episodes. In this experimental field area, conduit flow and diffuse flow drainage patterns have been distinguished by combining groundwater temperature and electrical conductivity data. Both parameters show large variations in water coming from conduit flow systems and low variations in water drained by springs draining diffuse flow systems. However, groundwater temperature displays the smallest variations, which seems to indicate that this parameter is less sensitive as regards characterising the degree of karstification, which is a key question in characterising the aquifer functioning.