Stock Photo - Piyain River is a tributary of the Surma River, and originates from the Umgat river of Assam The Umgat´s source is from the hilly areas of Assam Flowing south, the river enters Bangladesh through the Sylhet district and branches out into two: the Piyain and the Dauki, also known as Jaflong After entering Bangladesh, the Piyain follows a 7km route westward along the international boundary and turns southwest to meet the Surma River at Chatak The total length of the Piyain is about 145 km As the river is a hilly stream, it often causes flash floods and transports a huge amount of stones from its source area Goainghat, Jaflong, Sylhet, Bangladesh March, 2009