What are the points which favor the selection of a site for headwork

There should be economical, functional, and structural considerations for site selection:
As per economic considerations, the material should be near the proximity of the site. If there is any river section it should be narrow which helps to reduce river training work. Connecting site cost by railway and road should less. For the low cost of the construction site of the canal should be nearer to the culturable area.
As per functional consideration, the height of any obstruction should be moderate which gives a good command. as much as possible canal take-off should right angle to the river. The Flow of the river should be a central flow without silting and scouring.
As per structural consideration, a good foundation if available at moderate depth will be the best.