Background Atanasovsko Lake is a part of Bourgas lake complex, one of the three most significant wetland complexes for congregations of waterfowl along the Bulgarian Black Sea coast. The region of Atanasovsko Lake currently supports 288 bird species, 127 of which are listed in the Red Data Book of Bulgaria and identified by BirdLife as Species of European Conservation Concern (SPEC). Of these, 19 are listed in SPEC1 (globally threatened), 28 in SPEC 2 and 80 in SPEC 3, as species threatened in Europe. The area provides suitable habitats for 105 species included in Annex 2 of the Bulgarian Biodiversity Act (needing special conservation measures), of which 103 are listed also in Annex I of the EU Birds Directive. Atanasovsko Lake is located at the Via Pontica migration flyway and is a typical bottleneck for migrating soaring birds from Northern, Eastern and Central Europe (up to 240 000 storks and up to 60 000 raptors). It is the site with the largest concentrations of migrating white pelican (Pelecanus onocrotalus), the dalmatian pelican (Pelecanus crispus), the marsh harrier (Circus aeruginosus) and the red-footed falcon (Falco vespertinus) in Europe and second for the lesser spotted eagle (Aquila pomarina) after the Bosporus. Together with the other Bourgas lakes it is one of the favorite night roosts for pelicans and storks between the Danube delta and the Bosporus. Three types of habitats listed in Annex I of the Habitats Directive are found in the Atanasovsko Lake, but the lagoon habitat in Atanasovsko Lake is threatened by changes to the hydrological regime, drying, a degraded connection with the sea, pollution and eutrophication. Objectives The main aim of the project is to establish a functional, efficient and sustainable infrastructure for water management and the control of the coastal lagoon in Atanasovsko Lake. This will provide long-term improvements to habitat conditions and enable adaptation to the effects of climate change. The project also aims to: Reduce the impact of direct and indirect threats on Atanasovsko Lake lagoon and its priority bird species by securing sustainable habitat management, including improving existing and creating new breeding sites for priority bird species; Monitor and evaluate the effects of the proposed habitat restoration measures on the lagoon, other significant habitats, and Annex I bird species, and to feed this information into future site management plans; Improve the visitor experience at the site and to disseminate the project results to a wide European audience of site managers, ecologists and the general public; Enhance public understanding of the ecological, economic and social values of the coastal lagoons and raise support for the conservation of priority coastal habitats and bird species.Expected results: Specific outcomes will include the establishment of functional, efficient and sustainable infrastructure for water management and the control of the coastal lagoon in Atanasovsko, as well the mitigation of the impact of direct and indirect threats on Atanasovsko Lake lagoon and its priority bird species by securing sustainable habitat management, including improvements to existing and the creation of new breeding sites for priority bird species. The project will also increase public understanding and support for the ecological, economic and social values of the coastal lagoons. In the long term, the habitat improvements and other beneficial changes brought about through the project will make an important contribution to efforts to increase the populations of a number of Annex 1 species including collared pratincole (Glareola pratincola), Kentish plover (Charadrius alexandrinus), avocet (Recurvirostra avosetta), black-winged stilt (Himantopus himantopus), little tern (Sterna albifrons), common tern (Sterna hirundo) and the gull-billed tern, sandwich tern (Sterna sandvicensis).