Physicochemical assessment of water quality with respect to remote sensing and GIS techniques - Paper published in the journal Advances in Pure and Applied Chemistry

The paper informs that current techniques normally used in the country for monitoring and assessment of the quality of water bodies involve in situ measurement and/or the collection of water samples for subsequent laboratory analysis of the chemical, physical and biological characteristics of water. The use of recent advanced technical tools like the Remote Sensing (RS) and Geographical Information System (GIS) is however limited. 

The paper argues that while the conventional methods give accurate information about the quality of water at the geographically specific stations in the water bodies, these results are not very helpful in providing a complete picture of the quality of water of the whole water body. A number of studies on the assessment of the quality of water using the recent advanced techniques like the Remote Sensing in integration with Geographical Information System have brought to light the limitations associated with conventional methods. These include:

• Conventional water quality assessment methods are costly and time consuming as they involve travelling, sampling and laboratory analysis
• They do not give a complete i.e. spatial and temporal overview of water quality trends of the water bodies
• Conventional water sampling methods do not provide water quality data for every location in the water body
• It is difficult to monitor the water bodies constantly throughout the year, so continuous data over a time period cannot be obtained
• The usefulness of the data generated by the conventional methods may be in question due to insufficient quality control and quality assurance protocols like the extended holding times prior to the analysis and the use of non-standardised methods for analysis of the water samples

The inability of the conventional methods to monitor the quality of the entire water body can thus become a barrier in monitoring water bodies and water quality forecasting, which can have a negative impact on water resource management decisions and mitigation strategies, argues the paper. For the complete assessment of river water management and restoration of water resources, temporal and spatial data of the whole water body and more importantly a computer database to store, analyse and manipulate the collected data is required. The use of recent advanced techniques such as the Remote Sensing (RS) and Geographical Information System (GIS) in combination with the conventional in situ measurements can have all these advantages and can be successfully used for monitoring and managing the water resources of the country.

The paper informs that earlier evidence indicates that this technology has been successfully used in varied disciplines such as flood mapping and management, water treatment, drought monitoring, irrigation performance evaluation etc and argues that the use of RS and GIS for water quality assessment, especially for a geographically large country like India with vast water resources and limited financial assets, could open new and unmatched dimensions in monitoring capabilities of water resources. It would enable the concerned water regulatory agencies in effective and efficient water quality predictions and in taking prompt and consistent water management decisions for the conservation of the available water resources in the country.

The paper ends by arguing for a better co-ordinated approach between water quality monitoring agencies (e.g. CPCB and Water Quality Assessment Authority) and Indian RS and GIS institutes, which can help in executing advanced water quality assessment efforts using latest technology to further enhance and speed up the various aspects of water resource management such as:

• Water quality assessment
• Faster and accurate identification of pollution source
• Location of hot spots of poor water quality on a geographic basis
• Formulation of mitigation policies and implementation
• Feedback on the outcome of the water resource projects

A copy of the paper can be accessed at this link