Assessment of water quality status of Doyang River, Nagaland, India, using Water Quality Index

The Doyang River of Wokha district, Nagaland, NE India, has a strong economic and traditional attachment to the local people. It provides sufficient fertile plains and slopes for cultivation, good grounds for community fishing and hunting. It is not only important for the people of Wokha but also for the state of Nagaland because of the rich natural resources it provides. This study was conducted to assess the Water Quality Index (WQI) of the Doyang River from eight selected sampling stations. Maximum WQI values were recorded during monsoon season in all the stations followed by pre-monsoon and post-monsoon. Sampling stations located in the upstream of the river experience deteriorating WQI due to the presence of hydroelectric dam, changing landuse practices, increasing settlements and deforestation in the catchment and river banks. The overall WQI values showed good water quality status indicating suitability for different human uses. The present study points out that pH, DO and BOD played a central role in affecting the WQI of the river; however, in case of nutrient elements no such significant roles were observed in affecting the water quality of the river. The condition of water quality in our present study felt the necessity to adopt proper management policy and conservation efforts along the riparian zones of Doyang River.