Affiliation:
1. Institute of Oceanology, BAS
Abstract
Water and sediments in coastal areas interact at different scales, thus shaping the marine environment and providing physical habitat for ecosystems. Hence, the hydromorphological conditions represent a key aspect of aquatic ecosystems considered in the Water Framework Directive as supporting quality elements (alongside the physicochemical), which are expected to provide the boundary conditions for the biological quality elements. Any alteration in those can reshape the corresponding biological conditions at various spatial and time scales. The Directive states that coastal waters might be subdivided considering significant changes in bathymetry, substrate, or exposure. Typologies established by the Directive should reflect the natural variability in hydromorphological characteristics and processes. Therefore, the aim of the present study is to establish the type-specific hydromorphological reference conditions by identifying areas within water bodies that are relatively homogeneous from a hydromorphological point of view in order to better serve both determination and management of environmental state and designation of highly modified coastal waters based on a set of clear quantitative criteria. The data employed comprise remote bathymetry measurements, sediment mapping and wave exposure type. These layers were geospatially analysed to differentiate aquatic areas of similar hydromorphological conditions. About 100 such areas were delineated, in which conditions could be considered reference. At the same time, analysis revealed eighteen modified smaller scale areas, within the above-mentioned ones, which are considered hotspots of hydromorphological change in anthropogenically modified environment; hence, an object of future monitoring and specific management actions.