Constructed mainly for the purpose of irrigating the arid land stretching between the Ganges and the Jumna Rivers, originally extended from Hardwár to Cawnpore and Etawah, but has since been greatly enlarged, and at present (including branches) has a total extent of 3700 m., of which 500 m. are navigable; it has contributed to mitigate suffering caused by famines by affording a means of distributing ready relief.