Geology of the River
The Umngot River, also called the Dawki River, flows through the West Jaintia Hills district of Meghalaya. Its extraordinary clarity is a direct result of the region's geology. The river originates from the Eastern Shillong Peak and winds its way through hills composed of limestone and sandstone formations. These rocks act as a vast natural filtration system. As water percolates through the limestone, suspended particles and silt are trapped, leaving the water exceptionally pure and transparent. The riverbed, composed of smooth, colourful pebbles and stones, is visible even at significant depths, contributing to the optical illusion of floating boats.
This geological process is most effective during the dry season, from October to April. During these months, with minimal rainfall, the flow is calm and the natural filtration is at its peak. The water becomes so clear that visibility can reach up to 15 feet. In contrast, the monsoon season from June to September brings heavy rains that wash sediment from the surrounding hills into the river, temporarily turning the water murky and opaque. The river's path also forms a natural boundary, separating the Jaintia and Khasi hills before it flows across the border into Bangladesh, where it is known as the Shari Goyain River.
An Ecosystem in Plain Sight
The river's high transparency creates a unique aquatic environment. It supports a variety of fish, including several species of Mahseer and catfish. The clear water allows sunlight to penetrate deep, supporting photosynthesis for aquatic plants and algae that form the base of the local food web. This ecosystem is an important resource for local Khasi and Jaintia communities, who have relied on the river for fishing for generations.
Human interaction with the river is most famously embodied by the Dawki Suspension Bridge. This steel bridge was constructed by the British in 1932 to help trade. It hangs over the river and offers views of the emerald-green water below. The river is also a center for cultural events. A traditional boat race, known locally as "Sport Lieng," was revived in December 2025 after a 28-year hiatus, marking the connection between the local communities and the Umngot. In recent years, construction activities for a nearby highway have sometimes increased silt runoff, temporarily affecting the river's clarity and prompting conservation concerns.