No EU or regional GES indices have been adopted with regard to permanent alteration of hydrographical conditions (D7C1). However, three transitional water bodies of Polish Marine Waters have been found to represent subGES status basing on a national indicator. The reason for the subGES status is existing infrastructure related to, among others, inland navigation, tourism and recreation, fisheries and other interests. Restoration of GES in these water bodies would require the dismantling of some of this infrastructure and would therefore be detrimental to legitimate economic interests of local and regional importance. In some cases, as in the case of the Vistula river mouth, which is actually a man-made outlet built over a century ago, the dismantling of existing hydroengineering structures and restoring the river's original course would not only have serious economic consequences, including greatly increased risk of flooding in Gdansk, but would actually destroy important habitats which currently host a number of threatened bird species and Poland's only grey seal haul-out site. For these reasons, Poland believes restoring GES with regard to criterion D7C1 in the three water bodies concerned would be against public interest.