Implementing Environmental Flows in Transboundary Rivers under Climate Change

Rapid dam construction, rising water demand, climate change, and increasing pollution are exposing critical weaknesses in the governance of freshwater systems worldwide, particularly in shared river basins. Although environmental flows (e-flows) are widely recognised as essential for sustaining riverine ecosystems and long-term water security, their integration in transboundary water governance has remained largely symbolic, weakly enforced, and poorly adapted to climatic uncertainty. Even durable agreements in several regions prioritise volumetric allocation and procedural cooperation, offering limited mechanisms to safeguard e-flow regimes, as illustrated by treaties such as the Indus Water Treaty and the Ganga Water Sharing Treaty. This study argues that the persistent failure to operationalise transboundary e-flows in national and transboundary river basin governance frameworks reflects a deeper and systematic governance implementation gap that has not been adequately addressed in existing literature. Much of the literature examines legal provisions, economic instruments, and monitoring systems as separate domains rather than as interdependent components of operational governance. As a result, many transboundary river agreements pair legal allocation rules with flow monitoring but fail to link these to enforceable e-flow obligations or adaptive responses. To investigate this gap, the study undertook a structured comparative analysis of ten major international treaties and river basin agreements across Asia, Africa, Europe, and North America, covering both bilateral and multilateral transboundary river systems. Existing treaties were assessed to identify why most fail to deliver implementable e-flow solutions, while arrangements where elements of effective implementation exist were examined to extract transferable best practices for future transboundary water agreements. Based on the findings, the study proposes a three-tier governance framework to operationalise transboundary e-flows under climate uncertainty. The framework integrates climate-adaptive legal obligations, economic and financial mechanisms, and monitoring, reporting, and verification systems supported by remote sensing and GIS. By reframing e-flows as an implementable component of cooperative water security, this study makes both a conceptual and practical contribution to transboundary water governance, with implications for ecological resilience, conflict reduction, and long-term regional stability.

Keywords : Water demand, Climate change, River basin treaties, Ecological resilience