On Sunday, 4 August 2019 22:42:12 UTC+1, tony sayer wrote:

A lake near here was drained a few years ago for maintenance
of its dam. They used two siphon hoses each about 15cm diameter
and it took about two weeks.

Each hose had a strainer at the sucking end. I don't know how
the siphons were started, but they kept going happily until the
lake was nearly empty.

John