Improving the protection and conservation of the state of ecosystems for habitats of conservation interest and species of community importance in the Danube Delta Biosphere Reserve (RBDD) by ensuring optimal water circulation in the aquatic complexes Sontea-Fortuna, Matita-Merhei, Somova -Parches”. The project responds to LIOP requirements by contributing to: Priority Axis 4: “Environmental protection through biodiversity conservation measures, air quality monitoring and decontamination of historically polluted sites” Investment Priority 6c “Protection and restoration of biodiversity and soils and promotion of ecosystem services, including through Natura 2000 and ecological infrastructure” Specific Objective 4.1 “Enhancing biodiversity protection and conservation through appropriate management measures and restoration of degraded ecosystems” in accordance with Directive 92/43/EEC on the conservation of natural habitats and Directive 2009/147/EC on the protection of wild birds. The project meets the requirements of the EU Strategy for the Danube Region by contributing to: Priority axis: “Conservation of biodiversity, landscapes and air and soil quality” Action: “Preserving biodiversity and landscapes” contributing to the EU 2050 and 2020 vision for biodiversity, efficient management of Natura 2000 sites and other protected areas, protecting and restoring the most valuable ecosystems and endangered animal species. The project is type B: Implementation of management plans/sets of conservation measures/action plans for protected natural areas and approved species of community interest (including marine environment) action: • Measures to maintain and improve the conservation status of species and habitats of community importance, including ecological reconstruction of ecosystems on the surface of protected natural areas, including Natura 2000 sites. Active measure: Average increase of water depth in canals subject to hydrotechnical works of ecological reconstruction by 58.25 % compared to the current situation (average absolute value of 0.84 m). Activating water circulation in aquatic complexes leads to an increase of floodplain at average levels by 6 % and at low levels by 12 % with beneficial effects on the conservation/improvement of Delta habitats. The clogging of canals and guillos in the Danube Delta is a natural process that has been the basis for the formation of the architecture of the aquatic complexes between the three arms of the Danube. Beyond this natural process, it must be said that anthropogenic interventions prior to the 1990s were not aimed at maintaining the quality of Delta habitats, but quick access to certain areas. The channels created by man in the past have altered the hydrological system so that today there is an accelerated process of clogging of certain channels and guols in certain areas. Effect on flax