Note for Captain Sandoval is a written note found in Dishonored 2.
I'm an engineer, sir, not some kind of magician. If the foundation of the Grand Palace was built at an uneven grade, how am I supposed to keep it from flooding? How do you expect me to stop the Ocean itself?
Duke Abele wanted another entrance to his precious Vault, and we warned him that was a bad idea, given the foundation. So now, every time the storage room and the external passage flood, we're called in to fix the problem.
This is a fundamental structural problem - the Duke's house, as it were, is not built on a solid foundation.
Karnaca Engineering Corp
Grand Palace Maintenance
It can be found in the First Captain's Office, on the equipment storage rack immediately to the left of the entrance, during the mission The Grand Palace.