vacuming silt from pond

[stargazer]

My mother has a fish pond, it is slowly but surely filling in each
year with silt. I have an idea that I think might add some years to
the pond before it fills in but I don't know if it will work or not.

The pond is fed from a mountain stream, and drains out a culvert
pipe. There is about a 15' fall from the level of the pond to the
stream below the dam. If I buy some 5" black drainage pipe and use it
to siphon water like a swiming pool vacume. To suck the silt from the
silt basin will it simply clog the pipe. Has anybody ever tried this?

Thanks in advance!
Robert