- Summary
- Objectives
- Status
- Project Publications
With over 125,000 large and small dams across the world, freshwater ecosystems are among the most threatened globally. Resultant fragmentation, flow alteration, and changing sediment cycling regimes have adversely influenced freshwater biodiversity, which have extinction rates five times those of terrestrial animals.
Ecologically rich developing countries are witnessing a proliferation of river infrastructure projects to meet their growing demands. This is especially true in India, where over 9000 small and large dams have been proposed for further development in addition to the existing 5,100 large and 1,266 small dams. Many of these fall within the Western Ghats, a biodiversity hotspot and freshwater ecoregion, having high fish species richness and endemism. The rivers here support numerous ecological processes, millions of people, and over 350 fish species (66% endemic). However, the unscientific proliferation of river-related infrastructure is adversely impacting most rivers, their ecosystem services, biodiversity and dependent local communities. The dearth of hydrologic data availability has precluded effective basin-wide development planning, further exacerbating the issue.
We aim to address this gap by proposing an index-based framework to assess the cumulative impacts of dams, with the goal of facilitating freshwater habitat protection and basin-wide development planning. Here, we propose spatially explicit indices of river fragmentation and flow alteration based on readily obtainable data so that this method can be applied to data-deficit regions. We will validate the efficacy of this approach by assessing their ecological relevance and scale of influence using freshwater fish and macroinvertebrate communities. Establishing a predictive relationship between these indices and functional connectivity will enable the use of this method in scenario assessments and conservation planning. Specifically, we will be able to identify ‘good’ and ‘bad’ dams, no-go river stretches, and priority mitigation zones or dams that should be targeted for priority mitigation measures.
1. Develop an index-based approach to assess the impacts of existing and proposed river infrastructure projects.
2. Validate the above approach using empirical data of freshwater fish communities across a gradient of fragmentation.
3. Assess the trade-offs of river infrastructure development under various scenarios of dam development using the empirically validated indices.
4. Develop a Google Earth Engine application to visualise and download time-series trends in surface water area across India’s rivers and basins.
5. Collaboratively develop a citizen-science web application to collect information on India’s community-based fish sanctuaries on the Our River Our Life website.
- We have proposed two new indices of river network fragmentation – the Catchment Area-based Fragmentation Index (CAFI) and the Catchment Area-and Rainfall-based Fragmentation Index (CARFI). These indices have further been applied in simulated and actual catchments to further illustrate their properties and applications.
- Data on freshwater fish communities across a gradient of fragmentation was collected between January 2021 and March 2021 for index validation. Results indicate that the CAFI is a good predictor of fish functional connectivity. This supports the application of the metric across spatial scales to infer loss of network connectivity, even in data-deficit riverscapes such as those in India.
- The CAFI has been applied to the Netravathi River Basin, India and the Klamath River Basin, USA to inform basin-wide conservation and development planning. In the Netravathi, where dam building is still ongoing, prioritisation and sensitivity analyses were conducted to determine which of the proposed dams are ‘good’ (dams with low impact and high utility) and ‘bad’ (dams with high impact and low utility). Conversely, in the Klamath, the index was applied to determine priority sites for dam removal and mitigation.
- The JRC surface water dataset was used to create a time series (1991-2018) of surface water trends for rivers and river basins across India. Outputs include a Google Earth Engine website that will allow users to visualise and download a time series of surface water area for rivers and basins across India (https://pradeepkoulgi.users.earthengine.app/view/india-changing-rivers-and-basins). This was done in collaboration with Mr. Pradeep Koulgi.
- In collaboration with Ms. Neethi Mahesh and Jackfruit Solutions, we developed a web-application module on the Our Rivers Our Life website (https://www.ourriverourlife.com/home) to collect information on Community-based Fish Sanctuaries in India (https://www.ourriverourlife.com/fish-sanctuaries).