Karnaphuli (Bengali: কর্ণফুলিKôrnophuli; also spelt Karnafuli), the largest and most important river in Chittagong and the Chittagong Hill Tracts, is a 667-metre (2,188 ft) wide river in the south-eastern part of Bangladesh. Originating from the Lushai hills in Mizoram, India, it flows 270 kilometres (170 mi) southwest through Chittagong Hill Tracts and Chittagong into the Bay of Bengal. A large hydroelectric power plant using Karnaphuli river was built in the Kaptai region during the 1960s. The mouth of the river hosts Chittagong's sea port, the main port of Bangladesh.
Chittagong is situated on the banks of the Karnaphuli River between the Chittagong Hill Tracts and the Bay of Bengal. The city is a noteworthy seaside seaport city and monetary focus in southeastern Bangladesh. The Chittagong Metropolitan Area has a populace of more than 6.5 million, making it the second biggest city in Bangladesh. It is the capital of an eponymous locale and division. A water treatment plant has been set up by Chittagong Port Authority to source water from the Karnaphuli river for its uses. The plant will make the port self reliant in its water needs.
The Government has awarded a contract to build a two lane tunnel underneath the Karnaphuli river to China Communication Construction Company (CCCC). This will be the first underwater tunnel in Bangladesh. CCCC will get $706 million for its services with total costs expected to cross $1 billion.
The Kaptai Dam is the location of the Karnafuli Hydroelectric Power Station, constructed in Kaptai in 1962 and the only hydro-electric power plant in the country. An earth-filled dam on the Karnaphuli River, the Kaptai Dam created the Kaptai Lake, which acts as the water reservoir for the hydropower station. The power plant produces a total of 230 megawatts of electricity.
Like many rivers in Bangladesh, Karnaphuli is heavily polluted by agricultural runoff. Reducing the amount of oxygen available and harming aquatic life in the river. In 2015, a train carrying oil crashed over a tributary of the river. The spill caused environmental degradation.