What are perennial canals and inundation canals?

What are perennial canals and inundation canals?

Perennial Canals: These canals flow all the year round and thus they are known as perennial canals. They draw water from perennial rivers or from artificial lakes which maintain a high level of water on the upstream side.
Inundation Canal: These canals are directly taken out of rivers without building any barrage or dams. When the rivers are in flood, excess water flows into these canals. These canals are not useful during the dry months.