Contamination, Pollution and Quality

In this study, groundwater quality monitoring and evaluation of Greater Guwahati is presented based on the physico-chemical characteristics of thirty samples collected on grid pattern. The various parameters analyzed include pH, electrical conductivity, temperature, Dissolved Oxygen (DO), Total Dissolved Solids (TDS), alkalinity, hardness, Na⁺, K⁺, CA⁺⁺, Mg⁺⁺, NO₃^-, SO4^--, Cl^- and F^-. The results were compared with water quality standards prescribed by BIS and WHO.

The report describes the results of the study of arsenic pollution in groundwater in Nadia as well as the hydro-chemical study of the river Hoogly in West Bengal. The alluvial tract along the river Hoogly covering a stretch of around 470 km encompassing eight districts is affected by arsenic pollution of ground water, the source being geogenic.

The study presents detailed investigations of the chemical quality of groundwater in Jammu and Kathua districts (J & K), carried out to evaluate the suitability of water for various uses. The quality of groundwater of the area has been studied based on the physico-chemical analysis of thirty seven water samples collected from open wells between June and December, 1996.

Various parameters like pH, conductance, alkalinity, hardness, chloride, sulphate, sodium, potassium, calcium and magnesium have been determined for all the samples and compared with the standards to evaluate its suitability for drinking and irrigation purposes.

Irrigation water quality has been computed on the basis of Doneen’s Permeability Index and residual Sodium Carbonate. The higher values of some parameters at certain locations indicate the contamination in groundwater and make the water unsuitable for specific applications.

The report presents a methodology to assess the probability distribution of Dissolved Oxygen (DO) based on the Streeter-Phelp’s equation. The methodology involves the use of first order analysis and Monte Carlo simulation to analyze the uncertainty associated with DO. The mean and standard deviation of the parameters have been assumed as same for the study’s probability distributions.

The study presents a status report on hydrological problems of hard rock areas related to hydrological network design, groundwater quality, failure of open and borewells, regional flood formulae, groundwater balance studies, reservoir sedimentation, hydrological aspects of droughts, forest hydrology and drainage problems of black soil of the hard rock terrain.

The study evaluates groundwater on the basis of widely used graphical methods like Piper, Stiff and US Salinity Laboratory classification. The study concludes that, in general, the groundwater in the area varies from medium salinity to very high salinity, the latter being more common in the irrigated stretches. The irrigators are advised to ensure good land and water management practices in the fields, with particular emphasis on creating favorable leaching and drainage conditions to avoid further development of saline conditions in the area. 

The study applies geostatistical techniques to the groundwater quality data of December 1994 in parts of Jammu district. Groundwater quality deterioration has led to considerable interest in the design of investigative studies and monitoring programs on the issue.

Various management measures need to take into account the spatial and temporal behavior of groundwater. The spatial dependence between observations can be expressed by semi variance, which is a measure of the average similarity between observations at a given distance apart. One of the prime reasons for obtaining a semivariogram is to use it for estimation of the variable at unsampled locations.

A detailed survey of the river Hindon was carried out to understand the nature of waste effluents and their impact on water quality.  As per the study, the river water is subject to varying degrees of pollution, caused by numerous untreated waste outfalls of municipal and industrial effluents.

The main sources, which create pollution in the river, include municipal wastes of Saharanpur, Muzaffarnagar and Ghaziabad districts received through tributaries as well as direct outfalls. In the non-monsoon months, the river is completely dry, right from its origin upto Saharanpur town. The effluents of Nagdev nala and Star Paper Mill at Saharanpur generate the flow of water in the river.

The term skimming well is used for any technique employed with an intention to extract relatively freshwater from the upper zone of the fresh-saline aquifer. The types of skimming wells include: the conventional single strainer well, multi-strainers wells, scavenger wells, radial collector wells and dug wells.