A Shallow Excuse

A friend had booked a river cruise,
The Elbe the go-to river,
But got this message: “Sorry, but
This trip we can’t deliver.”

It seems that Europe’s waterways,
Due to a broiling summer,
Are much too low for ships to ply;
For tourists, what a bummer!

We’ve booked a cruise some months away,
Though I have got a notion
Hot weather won’t be quite enough
To drain away the ocean!