Hydrologie : recherche actuelle

Rainwater harvesting is an innovative and a suitable alternative approach of water supply that can be used by anyone. Rainwater harvesting captures, diverts, and stores rainwater for later use. It is a well known fact that during summer season there is a huge scarcity of water in northern regions of India and as such implementing rainwater harvesting would be beneficial because it would reduce demand on existing water supply reduces run-off, erosion, and also contamination of surface water. A rainwater harvesting system can range in size and complexity. All systems have basics components, which include a catchment surface, conveyance system, storage, distribution, and treatment. As such, we discuss in this paper about the prospects and possibilities of rainwater harvesting in Shimla region of Himachal Pradesh, which experience water shortages in summer periods due to increase in population and also climatic conditions. The result of our study shows that judicious storing of rain water all round the year and not only summer can be stored without incurring any significant losses. Further, the study shows that the sanitation water requirements for a family can be met for two months with storage of rainwater for one single month only. Further, the construction pattern of houses in Shimla (sloped roof structures) already provides an advantage in storing rainwater efficiently. The non-dimensional design parameters can be applied for any place which experiences a scarcity of water. The paper also presents a simple benefit-cost ratio for the designed rainwater harvesting system.

Stable isotopes (2H, 18O), 14C determination, and chemical analysis of deep groundwater and surface waters (river and springs) were used to investigate the sources of ground- and surface water, groundwater recharge mechanisms as well as possible sources of ions in groundwater in the semi-arid Shaqlawa-Harrir basin in Kurdistan. One hundred water samples were taken during wet and dry season. The d-excess varies significantly depending on temperature and humidity at the vapor sources. The means of the δ18O and δ2H values in the groundwater samples are -6.8 and -36.8%, for the spring samples -6.3 and -34.5%, and for the river samples -9.2 and -51.3%, respectively. The depletion in the δ18O content of some water samples is due to the higher altitude of some recharge areas (altitude effect). 14C data ranges from 3.4, 71.4 and 82.7 pmC and shows that recharges rates and means residence times vary greatly in the study area. Groundwater was mainly classified as Ca-Mg-HCO3 and Mg-Ca-HCO3 type; only five well water samples belong to the  Na-Ca-HCO3 type. All water samples investigated are suitable to be used as both drinking water and irrigation water.

Non-point Source (NPS) pollution has become an important concern in the protection of the aquatic environment and has received increased attention in recent years. In China, NPS pollution control is one of most important issues that need to be addressed to protect the aquatic environment in the next few decades. This paper reviewed and summarized three aspects of current agricultural NPS pollution studies in China: mechanisms, simulation models, and control technologies. This review outlines some shortcomings of previous research and the opportunities for future research. The results of this study indicated that the present research on NPS pollution mechanisms is not adequate. The lack of a database system, the uncertainty of models, and other issues have an effect on model applications. Control technology is still the only technique used for minimizing NPS pollution. For future studies, understanding and absorbing foreign NPS models, modifying related processes, and using related key parameters that are modified using Chinese characteristics are necessary for NPS pollution modeling in China. Furthermore, research on NPS mechanisms and system control technologies at a watershed scale will also be a key issue.

It has been known that workers of a honey bee colony bring water droplets into their hive, spraying it on the
frames and brood cells, and fanning their wings when ambient temperature rises higher than appropriate. Meanwhile several species from Namibian beetles demonstrate unique water harvesting strategies from the morning fog via the bumps and troughs above their elytra, where water droplets will condense and grow into a size large enough that they will slide down from its back to be consumed afterwards. Interestingly, the drop wise evaporation can be far more effective in its cooling effect than swamp cooler prevalently used in arid regions, according to the calculation conducted in this research. A group of parameters were selected as the boundary condition for calculating the evaporation rate of both a swamp cooler, and that of a drop wise evaporative cooler, according to the direct and indirect implication from the Monte Carlo Simulation, Ranz and Marshall Correlation of heat and mass transfer analogy and modified drag force expression for discharged water droplets. The following calculation shows under appreciable circumstances the drop wise evaporation can rival film evaporation. In consequence, the evaporative cooler system that is designed to utilize drop wise evaporation can be theoretically much more effective and efficient in water and energy use and easier to be regulated by humans than state of art evaporative coolers. The key parameters and some control strategies were pinpointed that can help raise the evaporation rate of a droplets cluster, shedding light on its further applications in industry and supporting human lives, like cooling tower of a power plant, and a fresh water harvesting net. Meanwhile, a conceptual design of an auxiliary structure, called hydro hair
system, is proposed according to the implication coming from Honey bees’ legs and hairs, and also the pattern of the surface of the elytra of Namibian Beetles

Nutrient budget was performed for the culture of Indian major carps; Catla catla (catla), Labeo rohita (rohu) and Cirrhinus mrigala (mrigal) in twelve fishponds, each of 0.04 ha water area. The stocking densities of carps were 7,500; 10,000 and 12,500 no. /ha (four replications for each stocking density and the ratio of each species was 1:1:1) and the average weights of catla, rohu and mrigal fingerlings were 6.5 ± 0.5, 5.0 ± 0.4 and 3.5 ± 0.4 g, respectively. The culture period was six months. Cow dung@14,000 kg/ha/yr was applied fortnightly as manure. Urea@200 kg/ha/yr and single super  phosphate@300kg/ha/yr were applied fortnightly as fertilizers. The fish were fed with an admixture of groundnut oil cake and rice polish in the ratio of 1:1@2% body weight of their biomass. The budget showed that recovery (in terms of fish yield) of nitrogen (N) decreased from 43 to 24% and the same for
phosphorus (P) also decreased from 16 to 9% with increase in stocking density. The recovery of organic carbon (OC) decreased from 28 to 16% with increase in stocking density from 7,500/ha to 12,500/ha. Effluent water (pond water at the time of harvest) accounted for 1.8 to 3.0% N, 2.5 to 4.0% P and 2.5 to 5.0% OC of the total inputs while bottom sediment accounted for 41 to 50% N, 70 to 75% P and 62 to 64% OC of the total inputs, respectively. Nutrient accumulation increased in both the effluent water and bottom sediment with increase in stocking density.

The microbial water quality of three different coastal beaches located in the south coast of Madeira Island, were monitored from May to December 2005 (Formosa and São Roque), and from October 2006 to June 2007 (Gavinas). Total and fecal coliforms and enterococci counts in two of the beach sites, showed a seasonal dependence, with highest values in autumn and winter suggesting a positive relationship with rainfall and a negative relationship with temperature. Of the three sampled beaches, Formosa beach showed the highest water quality and São Roque beach the poorest water quality. Impacted freshwater discharges and deficient water circulation in this recreational zone could be the causes for the lower quality of this beach. However beach rating was shown to be dependent on the indicator microbe chosen. The results obtained emphasized the need of differential sampling strategies according to beach specific characteristics, when assessing the water quality, as well as further sampling taking into consideration other variables, such as time of the day, tide, and microbial analysis of the freshwater inputs.

The property of water is highly related to the earth's environment and climate change. The fundamental
dynamical process of water is include formation and breaking of hydrogen bonds. This dynamic process, so far, is still poorly understood. We investigated weakening of the hydrogen bonds of water after ceramic Far-Infrared Ray (cFIR) irradiation and the resulting effects on physical and chemical properties of water. In this study, the Fourier transform infrared spectroscopy (FT-IR) was used to explore hydrogen bonding change of cFIR-irradiated water; in addition, capillary viscometers, Gas Chromatographs (GC), Differential Scanning Calorimetry (DSC), contact angles, Franz cells,  High-Performance Liquid Chromatography (HPLC), and capillary electrophoresis analysis were used to evaluate its physical characteristics, such as viscosity, volatility, temperatures of water crystallization, surface tension, diffusion, hydrogen peroxide dissociation, solubility of solid particles, and changes in pH of acetic acid. The cFIR treated water decreased in viscosity and surface tension (contact angles), but increased in the solubility of solid particles, hydrogen peroxide dissociation, temperatures of water crystallization, and acidity of acetic acid. The weakening of water hydrogen bonds caused by cFIR  irradiation is correspondent with our previous medicalbiological
studies on cFIR.

Co-existence of heavy metals and antibiotics becomes increasingly common in environmental pollution.
To investigate the stress of heavy metals on microbial resistance to antibiotics, fifty-six strains of bacteria were initially isolated from some swine water in Guangzhou city, based on their resistance to four antibiotics (cefradine, norfloxacin, amoxicillin, tetracycline) and five heavy metals (Pb2+, Cr(VI), Hg2+, Cu2+, Zn2+), a gram-negative isolate, Pseudomonas putida XX6, was selected to study the detail stress rules of heavy metals on its resistance to antibiotics. The antibiotics incidences of these isolates were in the order of norfloxacin>amoxicillin>cefradine>tetracycline, and that of P. putida XX6 was  cefradine>amoxicillin≈tetracycline>norfloxacin. The addition of heavy metals made all isolates’  resistance to antibiotics decrease, and Cr(VI) impacted their resistance to norfloxacin most obviously. If
the concentration of heavy metals was the most important factor affecting the resistance of P. putida XX6 to the antibiotics? There was a positive correlation between the bacterial resistances to antibiotics and heavy metals of low concentrations, and the correlation turned to negative with the concentrations of heavy metals increasing. But the bacterial resistance to amoxicillin or cefradine remained irrelevant to the concentrations of Cr (VI) or Pb2+. Results showed that the combined effect of antibiotics and heavy metals could alter their individual effect on bio-toxicity as well as on the biological removal capability of pollutants.