Dataset of temporal trends of surface water area across India's rivers and basins.

This dataset [1] quantifies the extent and rate of annual change in surface water area (SWA) across India's rivers and basins over a period of 30 years spanning 1991 to 2020. This data has been derived from the Global Surface Water Explorer, which maps historical terrestrial surface water occurrence globally using the Landsat satellite image archive since 1984, at a spatial resolution of 30 m/pixel and a temporal resolution of once a month. This monthly time-series was used to create annual composites of wet-season (October, November, December), dry-season (February, March, April), and permanent (October, November, December, February, March, April) surface water extent, which were then used to estimate annual rates of change. To estimate SWA trends for both river networks and their basins, we conducted our analysis at two spatial scales - (1) cross-sectional reaches (transects) across river networks, and (2) sub-basins within river catchments. For each reach and sub-basin (henceforth basin), temporal trends in wet-season, dry-season, and permanent SWA were estimated using the non-parametric Sen's slope estimator. For every valid reach and basin, the temporal timeseries of invalid or missing data was also computed as a fractional area to inform the level of certainty associated with reported SWA trends estimates. In addition to a Zenodo data repository, this data [1] is presented as an interactive web application (https://sites.google.com/view/surface-water-trends-india/; henceforth Website) to allow users to visualize the trends of permanent, wet-season, and dry-season water along with the extent of missing data for individual transects or basins across India. The Website provides a simple user interface to enable users to download seasonal time-series of SWA for any region of interest at the scale of the river network or basin. The Website also provides details about accessing the annual permanent, dry and wet season composites, which are stored as publicly accessible cloud assets on the Google Earth Engine platform. The spatial (basin and reach) and temporal (wet season, dry season, and permanent water scenarios) scales of information provided in this dataset yield a granular understanding of water systems in India. We envision this dataset to serve as a baseline information layer that can be used in combination with other data sources to support regional analysis of hydrologic trends, watershed-based analysis, and conservation planning. Specific applications include, but are not limited to, monitoring and identifying at-risk wetlands, visualizing and measuring changes to surface water extent before and after water infrastructure projects (such as dams and water abstraction projects), mapping drought prone regions, and mapping natural and anthropogenic changes to SWA along river networks. Intended users include, but are not limited to, students, academics, decision-makers, planners, policymakers, activists, and others interested in water-related issues.

A global perspective on tropical montane rivers.

Tropical montane rivers (TMR) are born in tropical mountains, descend through montane forests, and feed major rivers, floodplains, and oceans. They are characterized by rapid temperature clines and varied flow disturbance regimes, both of which promote habitat heterogeneity, high biological diversity and endemism, and distinct organisms' life-history adaptations. Production, transport, and processing of sediments, nutrients, and carbon are key ecosystem processes connecting high-elevation streams with lowland floodplains, in turn influencing soil fertility and biotic productivity downstream. TMR provide key ecosystem services to hundreds of millions of people in tropical nations. In light of existing human-induced disturbances, including climate change, TMR can be used as natural model systems to examine the effects of rapid changes in abiotic drivers and their influence on biodiversity and ecosystem function.

Big concerns with small projects: Evaluating the socio-ecological impacts of small hydropower projects in India.

Although Small Hydropower Projects (SHPs) are encouraged as sources of clean and green energy, there is a paucity of research examining their socio-ecological impacts. We assessed the perceived socio-ecological impacts of 4 SHPs within the Western Ghats in India by conducting semi-structured interviews with local respondents. Primary interview data were sequentially validated with secondary data, and respondent perceptions were subsequently compared against the expected baseline of assured impacts. We evaluated the level of awareness about SHPs, their perceived socio-economic impacts, influence on resource access and impacts on human-elephant interactions. The general level of awareness about SHPs was low, and assurances of local electricity and employment generation remained largely unfulfilled. Additionally most respondents faced numerous unanticipated adverse impacts. We found a strong relationship between SHP construction and increasing levels of human-elephant conflict. Based on the disparity between assured and actual social impacts, we suggest that policies regarding SHPs be suitably revised.