Blue Economy and Brown Rivers: Coastal Salinization, Estuarine Loss and the Indo-Pacific Security Agenda

By Saptak Mondal 

Where the Sea and the River Meets

Politics, like any other phenomenon, plays out across the margins of time and space. When understood in this way, estuaries emerge as a missing link in the Blue Economy’s policy horizon. These are the hybrid infrastructures where coastal settlements, aquifers, and livelihoods meet the margins of the sea. These have been under considerable threat from issues like diversion at the upper riparian regions, saline intrusion (SI), and sea-level rise (SLR). Hence, this connects to freshwater health of river mouths, incorporating food concerns and social concerns across the Indo-Pacific littoral. 

Thus, seemingly ecological issues get dragged into the arena of security concerns– in the words of Ole Waver, an “established radical” one. The 2012 UN Conference on Sustainable Development accorded considerable priority to “sustainable consumption and production patterns”, food security, sustainable energy for all, disaster risk reduction, and resilience.This helps us read the river mouths not only as ecological transition zones but as strategic nodal points, where social vulnerability and regional instability meet. 

Estuarine Understandings and Security Narratives within the Indo-Pacific 

Two significant case studies involving the Sundarbans from India and the Mekong Delta from Vietnam help shape the conceptual frame of the article: nodes of migration pressure and political instability across the Indo-Pacific littoral. The shared issues of saline intrusion, trapped sediments, upstream diversion, and loss of natural basin buffers plague both of them. This helps us connect to the broader securitization discourses, incorporating Blue Economy governance and Political Ecology. Hence, this idea of “estuarine security” lens seeks to redirect maritime policy attention towards the frontline freshwater risks. This simultaneously incorporates buffer restoration, guaranteed environmental flows, and a linked system of freshwater monitoring. This redirects India and its partner states’ Blue-Growth (BG) plans and perceptions in a widened manner, framing estuarine freshwater metrics and resilience planning accordingly. This lens reconfigures the river mouths as extremely significant hybrid socio-ecological infrastructures. These have largely remained outside the precincts of mainstream academic and policy discussions. Conservation and resilience of blue and marine infrastructures are the main pillars holding this lens up. 

The Threatening Triad: Salinity, Sedimentation and Sea Rise Sorrow of the Sundarbans

Remote-sensing studies and Landsat images have been observing the increasingly perilous rate of accretion, salinity, and ecosystem degradation in this area. As we delve deeper into the case study of the coastlines of the Bay of Bengal and the Sundarbans, we can find an alarming rate of net mangrove losses, shoreline retreat, and rising soil-groundwater salinity. These imperil the important economic structures, rice plots, freshwater wells, and even fish nursery grounds. The different strands of scholarship paint a grim scenario with perilous reports. The remote-sensing analyses explicitly show that decades of erosion and episodic cyclone surges have degraded the delta’s southern fringes. The other strand of the ecological studies documents salinity-driven shifts in mangrove composition and declining ecosystem services for fisher and farming communities, resulting in a decline in mangrove cover of about two percent. This has resulted in considerable loss and increased livelihood stress, catalysed by systematic patterns of seasonal migration from low-lying islands.

The Menace in Mekong

Moving farther to the east, we encounter the harrowing case of the Mekong Delta. Its 2020 saline intrusion episode forced Vietnam to envisage some of the most unprecedented and unexpected incidents. It made extensive stretches of areas unsuitable for rice and other essential livelihood supplies. Driven by land subsidence, upstream dams, riverbed sand mining, and relative SLR; saline intrusion made its way inland, crossing the hundred-kilometer margin in recent years. It degraded paddy soils and forced farmers working on fallow, infertile fields, or to switch crops. The World Bank analyses and regional studies document spikes in dry-season salinity in the Mekong that have pushed surface-water salinity to levels of four grams per litre in some canals. Even the Lancang–Mekong cascade, once preventive against subsidence and saline ingress, now adds to the crisis by dam diversion and sediment trapping. 

Cutting through the Coast: A Few Ways to Look Foward 

A comprehensive, integrated, expanded and implementable understanding of the contention is thus the call of the hour. The 2018 Lower Mekong Trans-boundary Cooperation Report emphasizes “bilateral estuarine flow-sharing compacts that commit the upstream states to minimum seasonal discharges”. It also suggests joint monitoring and fast dispute-resolution mechanics through grounding of operational rules using existing bilateral cooperative knowledge bases. 

This can be enhanced by incorporating estuarine salinity, sediments, and groundwater indicators into the national Blue Economy framework. This would help limit the investment criteria on ports, desalination, and fisheries, keeping the freshwater thresholds protected. Along with this, the funding and construction of an Indo-Pacific Estuarine Security Index blending remote sensing and in-situ data is becoming indispensable with each passing day. As the United Nations Joint Assessment Report on the Mekong Delta suggests, salinity intrusion distance, sediment flux, groundwater conductivity, and livelihood exposure demand attention with utmost immediacy. 

Lastly, it is imperative to promote community-centric resilience efforts through mangrove restoration, rainwater harvesting, saline-tolerant crops, and village desalination. These must be linked to investments in broader maritime security planning frameworks and climate finance windows for corrective investments. Hence, a purposive set of legal, technical, and financial tools can convert a looming regional fault line into a site of cooperative resilience. 

Saptak Mondal is a PhD Scholar, Department of International Relations, Jadavpur University, Kolkata. The views expressed in the above piece are personal and solely those of the author. They do not necessarily reflect the views of Kalinga Institute of Indo-Pacific Studies.