Special rights of people who own land that runs into a river bank (a "riparian owner" is a person who owns land that runs into a river).
While not an ownership right, riparian rights include the right of access to, and use of the water for domestic purposes (bathing, cleaning and navigating).
The extent of these rights varies from country to country and may include the right to build a wharf outwards to a navigable depth or to take emergency measures to prevent flooding.