Lake water volume calculation using time series LANDSAT satellite data: a geospatial analysis of Deepor Beel Lake, Guwahati

• Published in: Frontiers in Engineering and Built Environment
• Main Authors: Ishita Afreen Ahmed, Shahfahad, Mirza Razi Imam Baig, Swapan Talukdar, Md Sarfaraz Asgher, Tariq Mahmood Usmani, Shakeel Ahmed, Atiqur Rahman
• Format: Article
• Language: English
• Published: Emerald Publishing 2021-07-01
• Subjects: Lake water volume; Deepor Beel lake; Modified normalized difference water index; Landsat satellite data; Surface water mapping; GIS technique
• Online Access: https://www.emerald.com/insight/content/doi/10.1108/FEBE-02-2021-0009/full/pdf

Purpose – Deepor Beel is one of the Ramsar Site and a wetland of great biodiversity, situated in the south-western part of Guwahati, Assam. With urban development at its forefront city of Guwahati, Deepor Beel is under constant threat. The study aims to calculate the lake water volume from the water surface area and the underwater terrain data using a triangulated irregular network (TIN) volume model. Design/methodology/approach – The lake water surface boundaries for each year were combined with field-observed water level data to generate a description of the underwater terrain. Time series LANDSAT images of 2001, 2011 and 2019 were used to extract the modified normalized difference water index (MNDWI) in GIS domain. Findings – The MNDWI was 0.462 in 2001 which reduced to 0.240 in 2019. This shows that the lake water storage capacity shrank in the last 2 decades. This leads to a major problem, i.e. the storage capacity of the lake has been declining gradually from 20.95 million m3 in 2001 to 16.73 million m3 in 2011 and further declined to 15.35 million m3 in 2019. The fast decline in lake water volume is a serious concern in the age of rapid urbanization of big cities like Guwahati. Originality/value – None of the studies have been done previously to analyze the decline in the volume of Deepor Beel lake. Therefore, this study will provide useful insights in the water resource management and the conservation of Deepor Beel lake.