Battle of the Barrier Forts was fought along the river that has what total length?
Battle of the Barrier Forts: The Battle of the Barrier Forts (also known as the Battle of the Pearl River Forts) was fought between American and Chinese forces in the Pearl River, Guangdong, China in November 1856 during the Second Opium War. Pearl River (China):  Measured from the farthest reaches of the Xi River, the Pearl River system is China's third-longest river, 2400 km , after the Yangtze River and the Yellow River, and second largest by volume, after the Yangtze.
2400 km