Metagenomics Study of Kamvari River and Varal Devi Lake in Bhiwandi, Maharashtra to Apply Nature Based Strategies to Human-induced Challenges of Untreated Sewage Discharge and Enhance the Climate Change Resilience

India is suffering from the worst water crisis in its history with some 6000 million facing acute water shortage.This crisis will worsen as the demand is projected to be twice the available supply in 2030.The extent to which surface water and ground water is becoming polluted by anthropogenic activities including untreated sewage discharge, is adding to the complexities.Thus building understanding about the basic fundamentals of water, waterbodies as a bioreactor and role of microbial community are pertinent for the revival of lakes or riverine system.Prioritizing the nature based strategies this paper attempts to identify the characteristics, diversity and distribution of microbes in waterbodies to work on it, for an appropriate treatment mechanism to ensure its use as an alternative water resource.Metagenomics tool was first time used to study sewage dynamics in contaminated Varal devi lake and Kamvari river in Bhiwandi city, Thane dist.MS, as Varal devi lake supply 5 MLD potable water and may have adverse consequences.Findings of soil and water samples revealed potential environmental and health risk as the lake and river water showed presence of novel or less-characterized Leptospira and Turneriella species dominant in the system localized in Varal devi lake pumping and inlet discharge site.Hydrogenotrophic Methanogens were detected in soil samples, where as it was absent in water.A detailed microbiome taxonomic breakdown, abundance across samples, and insights into its ecological and health significance is comprehended with the recommendations to take appropriate measures of nature based strategies for ecological restoration of the lake and riverine ecosystem.Decentralized sewage treatment by septic tanks interception and constructed wetlands is suggested, simultaneously with Kamvari river rehabilitation from zero order stream onwards.Restoration of flood plains and buffer zones are also necessary by action on the encroachments, for self-regulation mechanism of the nature to prevail.This paper is an attempt to create awareness among the stakeholders about the waterbodies with river basin approach and strengthen scientific communication for good water governance.Engineering infrastructures like conventional STPs lack understanding and design of biological concepts and operationalization, this has led to the deterioration of almost all waterbodies.Hence it is imperative to work with integrated approach for future demand and water resources management by handholding between the community and government agencies.Disseminating the idea of decentralized community driven water conservation, river rejuvenation initiatives and to encourage use of advanced genomic technology to understand sewage degradation science for wastewater treatment, was the main goal of this research work.