This island is sinking at 6mm per year while sea levels rise. Residents have documented 50 years of encroaching salt water killing crops. A community becoming climate refugees in slow motion.
Kkkriku, CC BY-SA 4.0, via Wikimedia Commons
A delta starved of sediment
Munroe Island, or Mundrothuruthu, is a cluster of eight islets at the confluence of the Kallada River and Ashtamudi Lake. This inland island system was formed by the natural deposition of sediment carried by the river. Its existence depends on this constant replenishment to counteract natural compaction and erosion. This delicate balance was disrupted by human intervention.
The primary cause of the island's sinking, or subsidence, is sediment starvation. The construction of the Thenmala Dam on the Kallada River in the 1960s drastically reduced the flow of silt that historically built and maintained the delta. Without this incoming sediment, the island's soft, unconsolidated soil began to compact and sink. Studies suggest that some areas that were three meters above water level before the 2004 Indian Ocean Tsunami have since dropped by 0.5 to 1 meter. The tsunami itself is thought to have exacerbated the problem by altering the local seabed and increasing the frequency of tidal flooding from twice to eight times a year. The constant vibrations from the more than 62 trains that pass through the island daily may also contribute to the soil's destabilization.
A community retreating from the water
The consequences of subsidence, combined with global sea-level rise, are tangible and severe for the island's residents. At high tide, water regularly inundates homes, roads, and agricultural land. Hundreds of families have already abandoned their waterlogged properties, becoming some of Kerala's first climate refugees. Over the past few decades, the population has dwindled from over 15,000 to under 10,000.
The encroaching salinity has decimated the local economy. Saltwater intrusion into the soil and groundwater has made coconut and rice cultivation, once staples of the island, nearly impossible. The traditional coir retting industry, which involves soaking coconut husks in water, has also collapsed due to the changing water conditions. Freshwater sources are contaminated, and during high tides, public water systems often shut down, forcing residents to transport potable water by boat. The constant presence of stagnant, saline water has also led to an increase in waterborne diseases. A 2023 study by the National Centre for Earth Science Studies (NCESS) found that Munroe Island has lost almost 39% of its total land area, with some of the smaller islets experiencing depletion as high as 47%.
💡Fun Facts
The island is named after Colonel John Munro, a British Resident of the former princely state of Travancore who oversaw land reclamation efforts in the area in the early 19th century.
The island of Mundrothuruthu is not a single landmass but an archipelago of eight distinct islets with a total area of 13.4 square kilometers.
Before the construction of the Thenmala Dam, the island's soil was so fertile from river sediment that it was a major hub for coconut farming and coir production.
Despite its environmental challenges, the island is a popular destination for tourists who take canoe tours through its narrow, winding canals.
The island is a populated area and is accessible year-round. Canoe tours and homestays operate during daylight hours, typically from 7:00 AM to 5:30 PM.
Admission
There is no fee to enter the island. Costs apply for canoe tours, accommodation, and food.
Accessibility
The terrain is flat but often waterlogged or muddy. Travel between islets and along many local paths is done via small wooden canoes through a network of canals.
