The Burhi Gandak, runs a zig-zag course through the districts of Samastipur and Begusarai before covering a short distance in Khagaria district, running by the side of the town of Khagaria, and flows into the Ganges.
Floods are a known hazard of U.P. due to overflowing of its main rivers like Ganga, Yamuna, Ramganga, Gomti, Sharda, Ghaghra, Rapti and Gandak.