Restoration within the Srebarna Nature Reserve, Bulgaria
Year of issue
2025
Summary
A linking canal with a lock, constructed in 1994, restored the hydrological connection between Srebarna Lake and the Danube, enabling an annual inflow of river water and preventing the lake’s isolation that began in 1949. This intervention improved water levels, reduced eutrophication trends and supported the recovery of biodiversity, notably the Dalmatian pelican colony. The site, inscribed on the UNESCO World Heritage List, is managed by the Ministry of Environment and Water through the Regional Inspectorate (RIEW) in Ruse, and has been part of Natura 2000 since 2008, with a 673-ha buffer zone.
Recent UNESCO reporting (2024) confirmed the site’s official area at 638 ha after correcting a cartographic error from 2007. Management faces new challenges: predation of pelican eggs by invasive raccoon dogs and, more rarely, golden jackals, sometimes facilitated by late ice formation after mild winters. These factors have prompted measures such as protective fencing around nesting sites. The hydrological system and monitoring remain essential to maintain ecological values, while updated management planning and maintenance of hydraulic structures are priorities for sustaining the lake’s ecological health.
Photo Gallery
Location
44.10972, 27.07305
Project
NWRM
National ID
Bulgaria_09
Sector
Hydromorphology
Installation Date
1994
Implementation status
Completed
Contact
REC
Overview
Location of the project
The Srebarna Nature Reserve is located in north-eastern Bulgaria, on the right bank of the Danube River, about 2 km south of the river’s main channel and roughly 18 km west of the city of Silistra, near the village of Srebarna (Vetren). It lies along European route E70/Silistra–Ruse road. The site covers 638 ha, with a 673-ha buffer zone, and borders Romania across the Danube.
Country
Bulgaria
NUTS2 Code
Северен централен (Severen tsentralen)
Sponge measures implemented in the case study
Elimination of Grey River Bank Protection
Reconnection of oxbow lakes and similar features
Objectives
Restore hydrological connection between Srebarna Lake and the Danube River through a controlled inflow, reversing the isolation caused by the 1949 dike.
Stabilise and raise water levels in the lake to support wetland ecological functions.
Reduce eutrophication by flushing the lake annually with Danube water, thereby improving water quality.
Enhance biodiversity, with a focus on maintaining and increasing populations of key wetland species such as the Dalmatian pelican (Pelecanus crispus).
Comply with international commitments under the Ramsar Convention and later UNESCO World Heritage requirements, by halting ecological degradation.
Stabilise and raise water levels in the lake to support wetland ecological functions.
Reduce eutrophication by flushing the lake annually with Danube water, thereby improving water quality.
Enhance biodiversity, with a focus on maintaining and increasing populations of key wetland species such as the Dalmatian pelican (Pelecanus crispus).
Comply with international commitments under the Ramsar Convention and later UNESCO World Heritage requirements, by halting ecological degradation.
Involved partners
| Authority type | Authority name | Authority role | Comments | Authority responsibility |
|---|---|---|---|---|
| National water authority | Ministry of Environment and Water (MOEW) | Financing | National authority responsible for overall management and conservation of the reserve. Financing (state budget), policy direction, approval of management plans, coordination with UNESCO and Ramsar. | Responsible |
| Regional / sub-national water authority | Regional Inspectorate of Environment and Water – Ruse (RIEW Ruse) | Monitoring | Operational management authority at regional level. Day-to-day management, implementation of conservation and maintenance activities, local enforcement, site monitoring. | Responsible |
| Local water authority | Municipality of Silistra | Implementation | Local stakeholder and partner in site access, tourism infrastructure, and awareness activities. Support for visitor facilities, coordination with reserve staff for local development compatible with conservation. | Supporting |
| Other | UNESCO World Heritage Centre / IUCN | Monitoring | Oversight and periodic reporting for World Heritage status. Evaluation of conservation state, recommendations to the State Party, inclusion in monitoring cycles. | Supporting |
| NGO | Bulgarian Society for the Protection of Birds (BSPB/BirdLife Bulgaria) | Monitoring | NGO partner in species monitoring and conservation, particularly Dalmatian pelican protection. Field monitoring, anti-predation measures (e.g. fencing), public awareness, participation in LIFE projects. | Supporting |
Site Information
Climate Zone
Warm temperate dry
Precipitation
547.00 mm
Temperature (°C)
12.80 °C
Imperviousness
0.20 %
Elevation range
11
Slope range
0.02
Vegetation class
The reserve is dominated by extensive reed beds (Phragmites australis) and other emergent aquatic vegetation, with associated wet meadow and aquatic plant communities.
WFD Ecological status
Poor
WFD Chemical status
Good
Water quality status
A 2025 DEIMS site description notes recent shifts towards strong eutrophication and accelerated vegetation succession, partly linked to changes in Danube connection and groundwater use in the catchment.
Design and Implementation
Project scale
Micro
Project scale specifications
It involves a single, clearly defined site (638 ha lake and wetland, plus 673 ha buffer zone) on the right bank of the Danube, near the village of Srebarna. The intervention - construction and operation of a linking canal with a sluice (1994) - is a localised hydromorphological measure aimed at restoring water exchange between the lake and the Danube, improving ecological conditions within the reserve. While it benefits biodiversity of regional significance, its direct management and operations occur entirely at the site level.
Project area
60200
Size
638.00
Size unit
ha
Constraints
Interrupted connection with Danube River, Distance fom the main river
Favourable preconditions
Designated to Strict nature reserve
Financing
Compensations
Non
Policy and Governance
Policy description
Decrease of the water level, Eutrophication, Sediments accumulation,
Land ownership
The Srebarna Nature Reserve is state-owned. The land and water body are under the jurisdiction of the Bulgarian state, managed on behalf of the state by the Ministry of Environment and Water.
Policy targets
Runoff control
Improved Biodiversity
Increase Water Storage
Part of a wider plan
Non
Public consultation
Non
Has contractual arrangements
Non
Impacts and Monitoring
Monitoring System
Monitoring requirements
The site requires regular ecological and hydrological monitoring led by RIEW Ruse under MOEW oversight.
Monitoring parameters
Hydrology: water levels in the lake, inflow from the Danube via the canal.
Water quality: nutrient concentrations (e.g. total phosphorus, total nitrogen), chlorophyll-a, transparency (Secchi depth).
Biota: population size and breeding success of key species (especially Dalmatian pelican), composition of aquatic vegetation (extent of reed beds), presence of invasive species.
Threat factors: incidence of predation on pelican colonies, climatic events affecting ice formation, and habitat condition in the buffer zone.
Water quality: nutrient concentrations (e.g. total phosphorus, total nitrogen), chlorophyll-a, transparency (Secchi depth).
Biota: population size and breeding success of key species (especially Dalmatian pelican), composition of aquatic vegetation (extent of reed beds), presence of invasive species.
Threat factors: incidence of predation on pelican colonies, climatic events affecting ice formation, and habitat condition in the buffer zone.
Maintenance
Maintenance requirements
Maintenance focuses on ensuring the canal and sluice remain operational, through inspection, repair, and dredging as needed.
Impact Assessment Methodology
Performance impact assessment method
Catchment outlet
Performance impact estimation information
Measurment of the water level; Monitoring of the bird species
Socio-economic Impacts
Direct benefits information
Ecotourism and local economy : The restored hydrological regime has helped maintain the ecological character of the reserve, which underpins its appeal as a UNESCO World Heritage and Ramsar site. The visitor centre and observation points around the lake attract both domestic and international tourists, benefiting local businesses in the village of Srebarna (Vetren) and the municipality of Silistra (accommodation, food services, guided tours). Educational visits and eco-interpretation activities have increased environmental awareness in the local community, particularly on wetland conservation and species protection.
Cultural and scientific value : The site’s international designations have increased its profile, drawing scientists, students, and NGOs for research and conservation projects, and providing opportunities for capacity building among local staff.
Job creation : The reserve’s management provides employment for guards, maintenance workers, and guides, mainly under the RIEW Ruse administration, as well as seasonal work during specific conservation actions (e.g. fencing the pelican colony).
Cultural and scientific value : The site’s international designations have increased its profile, drawing scientists, students, and NGOs for research and conservation projects, and providing opportunities for capacity building among local staff.
Job creation : The reserve’s management provides employment for guards, maintenance workers, and guides, mainly under the RIEW Ruse administration, as well as seasonal work during specific conservation actions (e.g. fencing the pelican colony).
Biophysical impacts: Hydrology
Retained water
14.00
Retained water unit
mio m3/year
Increased water storage
4.00
Increased water storage unit
mio m3/year
Information on increased water storage
The construction of the canal and sluice in 1994 restored seasonal inflow from the Danube to the lake, reversing hydrological isolation since 1949.
This intervention raised and stabilised water levels in the lake.
This intervention raised and stabilised water levels in the lake.
Biophysical impacts: Biodiversity
Improved biodiversity
Oui
Information on improved biodiversity
The improved hydrological regime benefited wetland-dependent species, notably the Dalmatian pelican (Pelecanus crispus), whose breeding colony persisted after the intervention.
Other wetland bird populations and aquatic vegetation (extensive reed beds) were maintained or expanded in the years following reconnection.
Recent monitoring highlights negative impacts from predation by invasive raccoon dogs and, occasionally, golden jackals, sometimes facilitated by ice cover in late winter. Anti-predation measures (e.g. fencing) have been implemented to protect nests.
Other wetland bird populations and aquatic vegetation (extensive reed beds) were maintained or expanded in the years following reconnection.
Recent monitoring highlights negative impacts from predation by invasive raccoon dogs and, occasionally, golden jackals, sometimes facilitated by ice cover in late winter. Anti-predation measures (e.g. fencing) have been implemented to protect nests.
Biophysical impacts: Water & Soil Quality
Water quality overall improvements
Positive impact-WQ improvement
Information on water quality overall
Monitoring between 1998–1999 showed chlorophyll-a concentrations dropped to levels typical of mesotrophic conditions, indicating a reduction in eutrophication compared to the early 1990s. A 2025 DEIMS site profile reports more recent trends of strong eutrophication and accelerated vegetation succession, linked to changes in Danube connectivity and groundwater use in the catchment.
Soil quality overall improvements
N/A info
Biophysical impacts: Others
Ecosystem impact climate regulation
Increased permanent biomass
Lessons Learned
Key lessons
The hydrotechnical restoration of Srebarna demonstrates that local-scale interventions can deliver clear biophysical gains. The 1994 canal and sluice improved water levels, reduced eutrophication trends, and enhanced biodiversity within the reserve. These outcomes confirm that targeted hydromorphological restoration is effective for reversing site-level degradation in wetlands. However, the impacts at the wider river basin scale are insignificant or difficult to assess because of the scale difference, underlining the limits of local projects in influencing broader hydrological systems.
Another lesson is that restoration requires ongoing management. Infrastructure such as the canal and sluice must be maintained to keep hydrological functions effective. Without regular inspection, dredging, and repair, the benefits could be lost.
The case also highlights the need for continuous monitoring and adaptive responses. Tracking water quality, water levels, and biodiversity allows managers to react to emerging threats, such as invasive raccoon dogs and golden jackals preying on pelican nests, which required new measures like protective fencing.
Finally, Srebarna shows the value of linking conservation with socio-economic benefits. Its status as a UNESCO and Ramsar site has attracted ecotourism, education, and scientific research, benefiting local communities. At the same time, restrictions on resource use illustrate the need to balance ecological protection with local livelihoods through participatory planning.
Another lesson is that restoration requires ongoing management. Infrastructure such as the canal and sluice must be maintained to keep hydrological functions effective. Without regular inspection, dredging, and repair, the benefits could be lost.
The case also highlights the need for continuous monitoring and adaptive responses. Tracking water quality, water levels, and biodiversity allows managers to react to emerging threats, such as invasive raccoon dogs and golden jackals preying on pelican nests, which required new measures like protective fencing.
Finally, Srebarna shows the value of linking conservation with socio-economic benefits. Its status as a UNESCO and Ramsar site has attracted ecotourism, education, and scientific research, benefiting local communities. At the same time, restrictions on resource use illustrate the need to balance ecological protection with local livelihoods through participatory planning.
Success factors
| Success factor type | Success factor role | Comments |
|---|---|---|
| Legal obligations | Main factor | Strong legal protection and designation : UNESCO World Heritage and Ramsar statuses, plus Natura 2000 listing, ensured high conservation priority and obligations for management. |
| Attitude of decision makers | Secondary factor | The Ministry of Environment and Water, through RIEW Ruse, provides an institutional framework for daily management, enforcement, and monitoring. |
| Conducted assessments (incl. economic) | Secondary factor | Ongoing ecological monitoring : Regular tracking of hydrology, water quality, vegetation, and bird populations allowed adaptive management and targeted interventions (e.g. anti-predation measures). |
| Conducted assessments (incl. economic) | Main factor | Integration of socio-economic benefits : Ecotourism, education, and research activities linked to the reserve’s international profile have generated local economic opportunities and public support for conservation. |
Sources
Sources