Monitoring and Mapping Invasive Aquatic Weed Salvinia molesta using Multispectral Remote Sensing Technique in Tumaria Wetland of Uttarakhand, India

Indian reservoir’s managers have been facing problem in managing water and fisheries resources due to invasive aquatic weed infestation. Multispectral remote sensing data was used for monitoring the growth pattern of world’s worst weed; Giant Salvinia ( S. molesta Mitchell) in reservoir “Tumaria”, located in the Terai region of Uttarakhand (India). Temporal satellite data of Landsat-7 (ETM +) and Landsat-8 (OLI) for the period April, 2013 to May, 2015 were used for mapping and monitoring the weed. It was revealed that the reservoir was free from floating weed Salvinia until June, 2013 and for the first time appeared during September, 2013. It has covered 42% of the water spread area and subsequently covered 92% area until October, 2013. Active growth (matured weed) of Salvinia was observed when it covered 89–92% of water surface from October, 2013 to January, 2014 and also new growth (immatured weed) of Salvinia was observed on same months. Thematic map derived from the study can be used as a decision support tool for controlling aquatic weed infestation.