Search

The double spiral system was proposed as an alternative to the separate-channel method. The separate-channel method results in an overestimation of the total discharge in main channels and floodplains. The double spiral system considers the interaction between the main channel and the floodplain. The system lessens the additional energy needed to drive a certain discharge at a flow cross section, resulting in a lower flow depth.

The article informs about discharge of untreated sewage is the single important cause for pollution of surface and groundwater in India due and arsenic contamination of groundwater and how sewage are to be removed by applying different sewage treatments. Topics discussed include transported sediment may include mineral matter, chemicals and pollutants, and organic material; and localized erosion can cause structural failure, as bridges and overwater constructions.

The present paper starts by presenting an overview of the arsenic contamination in the groundwater in different parts of India. The paper goes on to present standards regarding arsenic in drinking water and then proceeds to give a statewise status of Arsenic contamination. Adverse effects of arsenic on the health of human beings, accumulation of arsenic in the food chain and ill-effects of using arsenicladen water for irrigation are elaborated upon in the paper. The paper proceeds to explore technological options to deliver arsenic-free water by various ways and means. Providing medical relief to affected people is also included. Methods for safe disposal of arsenic-laden sludge from arsenic filters and various issues related to the same are also key aspects of the paper. [ABSTRACT FROM AUTHOR]

The BILAN model (version 1.7) has been developed for assessing water balance components of a catchment using a monthly step. The structure of the model is formed by a system of relationships describing basic principles of the water balance on the land surface, the zone of aeration, including the effect of vegetation cover, and groundwater. Air temperature is used as an indicator of energy conditions, which affect significantly the water balance components. The model is run for two sets of parameters and the results are obtained. The results are in accordance with expected results. [ABSTRACT FROM AUTHOR]

The present paper gives an overview of saline water intrusion into coastal Nigeria. The paper places saline water intrusion into coastal Nigeria in the context of geology, hydrogeology, meteorology and land use of coastal Nigeria. The paper suggests ways and means to manage the problem of saline water intrusion into coastal Nigeria. [ABSTRACT FROM AUTHOR]

The complexity of the hydrogeological setup in coastal areas calls for the adoption of scientific groundwater management techniques. Excessive withdrawal of groundwater in coastal zones will lead to depression of the water table, with associated hazards such as putting the well out of use, rendering abstraction uneconomic with increased lift. A sustained regional groundwater drawdown below sea level runs the risk of saline water intrusion, even for confined coastal aquifers. Uncontrolled groundwater development may lead to reversal of the freshwater gradient, thereby resulting in saline water ingress into coastal aquifers. There are, however, several established methodologies to control and minimise the problems associated with groundwater extraction followed by saline water intrusion. This study developed a convenient and easily implementable analytical model for coastal groundwater management aimed at the control of saltwater intrusion. The technique includes withdrawal of coastal freshwater by means of qanat-well structures associated with artificial recharge through rainwater harvesting aided by percolation ponds and recharge wells. The proposed methodology is suitable specifically for not highly urbanised coastal areas with significant annual precipitation, good hydraulic conductivity of the aquifer and a low depth of fresh groundwater. As a case study, the model is applied to a coastal zone of the Purba Medinipur district of West Bengal, India. Adequate quantifications of the efficiency of the methodology are incorporated and relevant conclusions are drawn. [ABSTRACT FROM AUTHOR]