History of Technology in India, Vol. I: From Antiquity to c. 1200 A.D. v1.c24.s6.51

v1.c24.s6.51

But, the presence of canals is inferred from passages referring to water reservoirs which could be maintained only through a continuous supply from a perennial source56. A more direct reference can be seen in khātapravṛttim (AŚ.III.9.35), one of the three types of irrigation works, which means dug out to channelise. Likewise, the irrigation work (setu) of the type made by digging (khanya), as mentioned by the Nāradasmṛti were for diverting water (toyapravartana) and imply canals. A Ṛgvedic passage (III.33.4) may imply canals carrying water of rivers. Parallel to it is the Agnipurāṇa (272.4) reference to arms of rivers made to run into tanks.