Preparing turbidity and aquatic vegetation inventory for waterlogged wetlands in Lower Barpani sub-watersheds (Assam), India using geospatial technology

Abstract

Wetlands play a significant role in maintaining environmental stability. These have a complex of values like food storage, water quality maintenance, livelihood and support species diversity, etc. Wetlands inventory is the pre-requisite process for conservation and management practices. The study makes an attempt to delineate wetlands and prepare inventory for turbidity and aquatic vegetation in Lower Barpani sub-watersheds (Assam), India. The study utilized Landsat 8 OLI (Operational Land Imager) data during pre- and post-monsoon seasons, 2014. Wetlands during pre- and post-monsoon were delineated using supervised classification and threshold method. Wetland inventory for turbidity and aquatic vegetation was prepared during pre- and post-monsoon seasons. Single-band turbidity retrieval algorithm and normalized difference vegetation index (NDVI) were used to assess the level of turbidity and aquatic vegetation in GIS environment. The study revealed that the variation in the extent of water logged wetlands in sub-watersheds was due to water spread variation during pre- and post-monsoon seasons. All the sub-watersheds were characterized by medium turbidity which was attributed to sediments and silts brought with runoff in wetlands. Aquatic vegetation showed variation in its distribution across sub-watersheds. High vegetation indicated high turbidity and presence of nutrients. The study shows usefulness of remote sensing data in mapping and characterization of wetlands for preparing inventory and monitoring seasonal variation.

Keywords

• Waterlogged wetlands
• Turbidity
• Aquatic vegetation
• Remote sensing
• Lower Barpani