Transformation Analysis on Landuse/Land Cover Changes for Two Decades Between 1999 and 2019 CE with Reference to Aquaculture—Nagapattinam Coast, Southeast India

Even though the aquaculture is more lucrative compared to other high yielding variety of agricultural activities, the leakage of chemicals and wastages affects other landuse and land cover including the nearby rice fields in different parts of coastal India. We mapped the landuse/land covers of crop land, plantation, land with shrub, land without shrub, rural, urban and marshy land at Nagapattinam coast of southeast India by using Landsat series satellite images (TM and OLI) and estimated the changes with transformation analysis to assess the impacts of brackish water aquaculture between 1999 and 2019 CE. In two decades, the brackish water aquaculture activities have increased 2.5 times from 23.87 km 2 to 61.34 km 2 mostly by using 6.76 km 2 of crop land, 18.67 km 2 of fallow land, 3.64 km 2 of marshy land and 2.3 km 2 of plantation area. The accuracy assessment was carried out using 180 sample locations for each year (1999, 2009 and 2019). The accuracy assessment analysis shows overall accuracy of 81.66% (1999), 82.22% (2009) and 80.55% (2019), and overall Kappa coefficient values are 0.80, 0.81 and 0.79 for 1999, 2009 and 2019, respectively. This shows that the prepared Lu/Lc features are accurate enough for landuse and land cover change investigations. Our results and maps provide quantitative data to take proper actions to regulate the anthropogenic land alteration practices in this ecologically sensitive coastal area.