水文学: 現在の研究

Water is a natural resource, a basic necessity to living things including humans and wildlife, food production, food security, sustainable development and alleviate the poverty of the country. Despite of having blessed with enormous water resources (e.g., Mt. Himalaya’s originated Holy River Ganges, and its several tributaries from the north, Kaveri River in the south, ever rain forests [e.g., Mousinram near Cherrapunji], world’s tastiest waters of the Siruvani River in Coimbatore, Western Ghats Basin, network of fresh water resources etc.,), “water problem” is huge ‘a big threat and cross cut problem in India’. Due to hectic population increase and drinking water consumption, decreased rainfall, the ‘water problem’ in India is becoming a major threat. Particularly, water pollution, poor sanitation, dwindling/decrease in rainfall, groundwater levels and water scarcity designs the world’s second most populous nation. Water is most essential for livelihoods, agriculture, energy production, industrial development and for several other potential consumptions. In India, ‘water problems’ arise mainly due to poor management, negligence, in appropriate technology and poor responsibility by the peoples and needed to be taken special precautionary measures. Consequently in this paper some major issues related to Indian waters during the past and currently have been reviewed and highlighted.

The accuracy of rainfall predictions in the EPA’s BASINS (Better Assessment Science Integrating Point and Nonpoint Sources) decision support tool is affected by the sparse meteorological data contained in BASINS. The objectives of this study were improvement of using the entropy theory to supplement the precipitation data are significant when the watershed’s meteorological station is either far away or not in a similar climatic region. When the station is nearby, using entropy theory to supplement the precipitation data produces similar results. And this study assessed the improvement of stream flow prediction of the Hydrological Simulation Program-FORTRAN (HSPF) model contained within BASINS using the hourly precipitation estimates in Feitsui reservoir watershed. Our results demonstrated consistent improvements of daily stream flow predictions in Feitsui reservoir watershed when precipitation data was incorporated into BASINS. Our analyses also showed that the stream flow improvements were mainly contributed by entropy theory to supplement precipitation data; partially due to the constraints of current BASINS-HSPF settings. However, entropy theory to supplement precipitation data did improve the base flow prediction. The entropy theory method showed 10.17 to 25.51 percent less error than the Thiessen polygon method and Arithmetic to supplement the rainfall data. And used entropy theory supplement the rainfall data to simulate stream flow that RMSE values between 58 and 182. This study demonstrates entropy theory to supplement precipitation has the potential to improve stream flow predictions, thus aid the water quality assessment in the nonpoint water quality assessment decision tool.

This paper describes the application of a conceptual rainfall runoff model to investigate the peak and monthly flows at the Sarisoo River Basin on the North West of Iran. The model was calibrated using measured stream flow data and then validated for three years. Calculations of level and time of peak flows are vital for designing structures downstream in the catchment areas. The simulated peak flows were occurring in the months of February in 2003, 2006 and 2007 with approximate values of 6.32, 9.35 and 6.13 m3s-1 respectively. After calibrating 9 NAM parameters using record data of daily rainfall, monthly evaporation and daily discharge in the period of 1th October 2003 to 31th March 2006 and validating the model daily discharges were calculated for 12 years. The outputs of the calibrated model are able to be used in the assessment of water resources management models like Mike Basin, WEAP… because they normally work based on monthly flows with a large time horizon. The results show that monthly averages of mean, maximum and minimum flows are about 10%, 2% and 33% less than daily computed Nash–Sutcliffe coefficients, all calculated over a period of 12 years.
The optimum values of the 9 NAM parameters obtained during the calibration procedure are presented. The reliability of MIKE11 NAM was evaluated based on the Nash–Sutcliffe coefficient (R2), Root Mean Square Error (RMSE), peak flow (RMSE) and low flow (RMSE). The R2 obtained during this study is 0.74.

An Electrocoagulation (EC) process has been conducted in an electrolytic cell with iron electrodes to eradicate and, consequently, recover copper and cobalt from synthetic and industrial effluent samples. Purity of recovered metal has been determined by synthesis of crystalline salts and analysis by X-ray diffractometer (XRD). Operating parameters such as metal ion concentration, pH, current density and temperature were investigated for removal efficiency of copper and cobalt. Results indicated that removal efficiency of copper (pH 3.5) and cobalt (pH 4.5) was 98.8% and 97.9% respectively. Adsorption studies were investigated by applying Langmuir and Freundlich adsorption isotherm models. On the basis of regression coefficient R2 values, Langmuir isotherm models were obeyed. Adsorption kinetic studies demonstrated that the EC process was pre-eminently depicted using a pseudosecond-order kinetic model. The present method is simple and efficient compared to existing water treatment technologies.

In the first part of the present research work, the synthesis and characterization of a multilayer PVA/CA/PEG membrane was attempted. Where membrane performance and applicability was investigated for reverse osmosis (RO) desalination of saline water. For this purposes, various synthetic membranes were prepared and characterized for the desalination process. Reverse osmosis parameters of different multilayer composite membranes were evaluated compared to a reference membrane of a desalination station in Egypt. Values of both salt rejection and water flux were assessed as a measure of membrane efficiency. In the present work, selected samples of CA/PEG and PVA/CA/PEG were engaged as membranes for the reverse osmosis process of different feed concentrations of groundwater, brackish, highly saline and also extremely saline water (sea water). Feed and permeate concentrations were determined by conductivity measurements. In addition, to suitable application of the prepared synthetic membranes, the antimicrobial sustainability was also evaluated where prospective function against gram +ve and gram -ve was depicted.

The study examined the spatial characteristics of boreholes of ten selected locations with the opinion of
appraising the sustainability of groundwater resource in the Deltaic Formation, Niger Delta Nigeria. Data on Borehole Parameters (Depth of Hole, Screen Length, Yield of Well and Drawdown) were obtained from the Rivers State Ministry of Water Resources, Port Harcourt, Rivers State. Both Descriptive and Inferential Statistical methods were employed in the analyses of the data while the relationship between the well yield and other borehole parameters was also modelled. The result showed that the aquifers of the study area are very thick, deeply located, highly porous and saturated; emphasizing high yield potentials. It was also revealed that the basin contains adequate water to sustain her population as indicated by the high mean yield (30,056lit/m) recorded for the study area. Finally, the result of the correlation statistics showed that the yield of well increases with depth of hole (r=0.82), rate of drawdown (r=0.62) and length of screen (r=0.63); and that the rate of drawdown increases as the length of screen increases (r=0.99). The study concluded by emphasizing the indispensability of adequate knowledge of hydrogeology in groundwater exploration and development particularly in regions of complex geological heterogeneity such as that of the Deltaic Formation.

The acid rain caused due to air pollution from the presence of CO2, SO2 and NO2, has long been experienced world wide, albeit with variation of intensity of occurrences in different regions and time of a year. In this study a product and process was developed to eradicate insitu the CO2 and SO2. The product and Process designated as Geoact-Ca5 was adequately tested for the pollutants that exist in stratified columnar situation similar to that in open environment. Action of the Geoact-Ca5 converts the polluting agents responsible for causing acid rains and its harmful effects in to inert and harmless product or even to some useful products such as CaCO3 and CaSO4. The product and process is applicable for eradication of acid rain causing pollutants such as CO2 and SO2 in any region and before the occurrence of events of rain or snow and situation that leads to the dry deposits of acid rain. Thus, unmaneuverable problem of acid rain can be controlled by applying the Geoact-Ca5 at selected locations and time of the year. The budget for the application of Geoact-Ca5 can be derived by selling the carbon credits generated by accounting the eradication. New areas of research are suggested.