Mapping water quality parameters of select lakes of Ahmedabad, India using open-source geospatial tools

Freshwater sources in urban areas of developing countries are under constant threat of deterioration due to anthropogenic activities. As a result, the potability of water from such sources becomes questionable and quantifying its condition through timely in-situ measurements or satellite datasets in case of the source’s inaccessibility is necessary. Maintaining a record of such measurements, regularly updating and visualizing them spatially on a geographic layout has now become possible with the advent of geographical information systems (GIS), thereby aiding the decision-makers in formulating strategies for sustainable management of such sources. Moreover, the development of open-source GIS software solutions has brought about a revolution, allowing even a novice to reproduce a routine and build one’s own geospatial application. Here, an attempt has been made to build a geospatial database of eighteen major lakes of Ahmedabad city in the western Indian state of Gujarat using Quantum GIS (QGIS). Hard-copy maps procured from the municipal authorities provided the municipal boundary and central location of each lake. A thorough literature review gave information on seven water quality parameters: alkalinity, pH, calcium–magnesium hardness, conductivity, total dissolved solids and turbidity, which formed separate layers of the developed database. Using the spatial query feature of QGIS and the Indian standard (IS) on drinking water quality: IS 10500, the lakes possessing the maximum concentration of every considered parameter have been identified, thereby requiring urgent intervention for their restoration as a water supply source and prevention of their ecosystem from dying a slow death.
The 28th IUGG General Assembly (IUGG2023) (Berlin 2023)