THE LARGE OUTER EARTHEN FORTIFICATION OF PLISKA (Pavel Georgiev – pavel_g@gbg.bg, Radoslav Vasilev) The explorations aimed at clarifying the features and chronology of the “double passage” in the eastern earthen rampart of the outer fortification of Pliska. The beds of two open canals for meliorative water-supply to the Outer Town of Pliska during the 9th century AD were traced out. The canals were dug into the marl bedrock. The width of their upper part is 4 – 6 m, the width of their bottom is 0.50 – 1 m and the depth is down to 3.50 m from the contemporary surface. Canal No. 1 took water from a shallow natural basin in front of the ditch and transported it to the dry valley located nearby. The canal passed through the northern passage of the earthen rampart. Canal No. 2 passed through the southern passage of the earthen rampart and transported water to the same dry valley. Animal bones, sherds of pots dated to the 9th – 10th centuries and fragments of bricks or water-pipes were found within the canals.