Inundation canals are made under the following circumstances.
- If river water level during floods remains high for a considerable length of time.
- If sufficient floodwater reaches the river in March or April, the flood water may be use to submerge the land, so that the Kharif crop could be sown.
- If flood water remains available say up to late September, the Kharif crops can irrigate up to this time and, even, areas may be submerg to sow early Rabi crops in October.
- Areas to be irrigate when in the vicinity of the river banks the inundation canals may serve the purpose of irrigation.
- When soil has good stabilizing power so the bed and banks of the canal remain stable.
- Inundation canals are more or less similar to permanent canals.
- The major difference is that, in the case of permanent canals, permanent masonry or concrete works.
- Like weirs, barrage, head regulator, fall, cross regulator, are constructed to regulate the supplies, but in case of inundation canals, all these works are not there.
- In order to take water into the canal, the riverbank is cut.
- The rising floodwater in the river enters the inundation canal through the cut, made in the bank.
- Sometimes in the worst floods, the cut made in the river bank is erod and develops into a large deep cut.
- This may cause flooding of the adjoining areas the capacity of the canal may not be that much to deal with the situation.
- To avoid such possibilities of flooding, a crude type of head regulator or weir may be made at the off take point.