the highest point that the water touches
High Water Mark of the Rebellion Monument was created in 1892.
the state owns the land below the high water mark
What is the famous battle in Pennsylvania became known as High Water Mark of the confederacy
The Battle of Gettysburg is often referred to as 'The High Water Mark of the Confederacy'.
If by "high water mark" you're referring to flooding, there really is no way to calculate it. howver, if the question is how to determine of a property is subject to flooding, the US Department of Housing and Urban Development has maps which will show lands which are located in a 50-year or 100-year floodplain.
Generally, private property ends at the mean high water mark. However, you may need to check the laws of your particular state. The laws in Florida are being modified where the state has added footage to the beaches for erosion control projects. The state does not consider that added land, which changed the old mean high water mark, as belonging to the abutter and suits have been filed. The added beachfront has been dedicated to the public.
Gettysburg
Gettysburg
Gettysburg is sometime called the "high water mark of the Confederacy."
Mark
During a spring tide, the high water mark would be high up on the beach on the flood, and very far out on an ebb tide. During a neap tide, the high water mark is not so high or so low as during a spring tide.
A hurdle rate would be a minimum return required before a management incentive fee would kick in. An minimum requirement example might be LIBOR + or a Risk Free Rate, etc. A high water mark is the highest peak in value an investment fund has reached. High water marks are setup to ensure that high fees aren't paid for poor performance. In other words, if the manager loses a bunch of money, you don't pay a performance incentive fee until the fund is back up to the high water mark.