Encyclopedia
Internal Waters
Internal waters include all flowing waters and waters in a state of slow water exchange, groundwater (water objects) located within the territory of the State, and, if the territory of the State borders on the sea, also waters situated landward from the baseline of the territorial sea (internal sea waters), as well as groundwater flowing towards that baseline from which the width of the territorial sea of the State is measured
Source: "MODEL WATER CODE FOR PARTICIPANT STATES OF THE COMMUNITY OF INDEPENDENT STATES"