Natural hazards and anthropogenic threats in natural reserves along the Romanian Black Sea coast and the River Danube (Dobrogea)

Category Other
Group GSI.IR
Location International Geological Congress,oslo 2008
Author Seghedi, Antoneta۱; Oaie, Gheorghe۲; Stanica, Adrian۲
Holding Date 08 September 2008

The main protected areas in Dobrogea, an area from the Carpathian foreland bounded by the Danube and the Black Sea, include the Danube Delta Biosphere Reserve, the Macin Mountains National Park, the Little Island of Braila Natural Park and 2 Mai - Vama Veche Natural Reserve. Beside these, more than 70 small-sized natural reserves are scattered over the area.
Exposing a well preserved part of the Hercynian basement of the Cimmerian North Dobrogea Orogen, the area of the Macin Mountains National Park includes of metamorphic formations and Palaeozoic sedimentary and volcano-sedimentary successions intruded by Hercynian granitoids. The main natural hazards are earthquakes and floods, while another main threat to both geo- and biodiversity is represented by quarrying: there are two active quarries located at the park boundaries, an old quarry is being reactivated and there are no buffer areas around most of the park borders.
Located on the Danube, the Ramsar site Little Island of Braila Natural Park is a wetland in the green corridor of the Danube with natural flooding regime, a typical pre-deltaic wetland area, conserving natural ecosystems which are nowadays unique in Romania. The main natural hazards for this site are represented by flooding and draught. Due to human overuse and pollution, the Danube River concentrates raw sewage from cities, chemicals from agricultural activities, waste from factories, oil from ships, etc. This pollution is later washed up on the north-western Black Sea shelf area, affecting thus the marine ecosystems and their diversity. Chemicals in water have affected much of the aquatic life and reduced the Danube’s fishing industry.
There are 2 natural reserves along the Romanian Black Sea coast: the Danube Delta Biosphere Reserve (from the World Heritage List), with a total length of the coast of about 240 km and 2 Mai - Vama Veche Natural Reserve, located South of the Mangalia Harbor. Very low relief of the coastal area along the Danube Delta and the Razelm-Sinoe lake system make the shoreline and beaches vulnerable to natural hazards like large storm waves in winter time and potential tsunami-type waves related to seismic activity on major faults in Dobrogea and in the offshore area.
Coastal erosion, accelerated and/or triggered by human activities, dramatically affects both natural reserves. Human interventions along the Danube River (damming, embankments, channel cutting) have decreased by 50% the sand discharge into the Danube Delta coastal area and altered the overall solid and liquid discharges between the three main Danube distributaries. Building of harbour and channel protection jetties, piers and groynes, resulted in changes in the direction of longshore currents, blocking the sediment transfer along the coast and generation of inverse local currents. The hard coastal defence works have altered the local coastal circulation and sediment dynamics, increasing thus coastal erosion in the neighbouring beaches.