Developing the recommendations for restoration of Ashtamudi Lake, Kerala, India, by data analysis based on a novel water body index using Google Earth Engine

Abstract

Continuous monitoring of the water bodies is necessary for the hydrological and ecological systems of any region to remain viable. This study expands on existing approaches for the delineation and monitoring of changing dynamics of lakes using remote sensing. A hybrid index namely water index built-up index (WIBI) is derived by subtracting normalized difference water index (NDWI) from normalized difference built-up index (NDBI), and it is used for the detection and analysis of area and flow changes in the water body. NDWI is efficient in delineating the water bodies, even in vegetated areas, due to its reliance on the green band, while it may overestimate the results in regions with significant built-up areas. NDB index, which utilizes the short-wave infrared (SWIR) band, is highly effective for detecting built-up areas. The intuitive hybrid index integrates the key features of both NDWI and NDBI to enhance the accuracy of analysis. The application is investigated at Ashtamudi Lake, Kollam, India, and the results are compared with water body detection indices such as NDWI and SWIR1. This study further focused on assessing water quality by examining temperature, turbidity, and chlorophyll content using Google Earth Engine data. The other water quality parameters like pH, total dissolved solids (TDS), conductivity, and salinity was also determined by using water quality analyser as a field data. The proposed method successfully captured the water quality parameters and lake area in comparison with field measurements. These findings could aid in the development of strategies for the rejuvenation of Ashtamudi Lake.