The past year was very successful for one of the most important conservation activities under the LIFE project "Lagoon of Life" - the restoration of mini-dykes and the cleaning of salt canals in Atanasovsko Lake. These activities aim to reduce the effects of coastal lagoon habitat fragmentation and improve connectivity between individual basins. This ensures good circulation and refreshment of water throughout the lake in favor of inhabitants and salt production.
During the two years of the project, 5920 m of mini-dykes were restored and 5085 m of internal canals were cleaned, which is 35% of the planned volumes of work on this activity. For the first time, new technology was applied in the construction of mini dykes in a dry way. The adjacent pools are emptied of water and the excavator runs dry. This reduces recovery time (and birds disturbance) as well as the risk of equipment sinking and inability to work. This method is applicable only for shallow pools with low water volume and high salinity - the so-called "beds" that are not particularly attractive to birds due to their poor nutritional base, so the negative impact on them is minimized.
The cleaned internal salt channels provide between 3.5 and 6 times better water conductivity in them. The improved circulation leads to increased migration of nutrients and aquatic organisms between the basins, which is invaluable for maintaining the life of the ecosystem of Atanasovsko Lake. At the same time, as a result of the cleaning of the canals, the eutrophication of the waters flowing through them is reduced by almost 40%.
The restoration of the mini dykes provided new 2.35 ha of areas favorable for nesting of priority bird species. For example, the extremely rare and endangered Kentish Plover is one of the species that already successfully nest on the new mini-dykes.
At the end of the year, began the work on the rebuilding of the Northern Lake's main sluice. It will improve the lagoon's flood safety and will provide a normal supply of fresh seawater. With the completion of the work in 2021, the sluice will allow easy and fast management of the water level throughout the Northern part of the Lake.
And while 2020 was one of the driest in the new century with only 316 l / m2 of rain (60% of the annual rainfall norm) and the sixth driest year in the entire history of measurements in Atanasovsko Lake since 1937, then 2021 started with torrential rains. Only for the period 8 - 13 January in Atanasovsko Lake a record amount of 152 l / m2 was reported. At the end of January, the total amount of precipitation reached 185.5 l / m2. This is more than 1/3 of the annual rainfall rate. The data show that these are the highest amounts of precipitation since the statistics were kept, and the second-highest record with 170.9 l / m2 is from February in the distant 1956.
These huge amounts of water increased the level of Atanasovsko Lake by 30 cm or an additional about 5 million m3 of water (1/3 of the water volume of the lake), but the restored and maintained system of dikes, barriers, canals and locks did not allow this water to destroy the infrastructure of the lake and to mix the water volumes of the separate basins. Thus, the specific salt gradient of the lagoon was preserved and the important areas for water circulation and bird nesting were preserved. The high level flooded the peripheral parts of Atanasovsko Lake, where the valuable habitats of the glasswort and the sea dzuka are located, and to provide them with the vital winter flooding, necessary for maintaining a favorable nature protection status.
Without the project activities, these water quantities would be disastrous to the coastal lagoon ecosystem. This once again proves the high conservation value and the invaluable effect of the conservation work for the protection of the so vulnerable Atanasovsko Lake.