Influence of the Coastal Zone Technogenesis-related Changes on the Coast Development Vakhtang Gvakharia Gamma Consulting Ltd Natural and man-caused degradation of coastal zone • Problem statement • Causes Black Sea coast line Length of the Black Sea coast line is ~4,340km: • 300 km belonging to Bulgaria, • 313 km to Georgia, • 225 km to Romania, • 475 km to the Russian Federation, • 1,400 km to Turkey and • 1,628 km to Ukraine. Subdivision of the Black Sea coastal zone • Low, accumulative coasts (mostly related to the main river mouth zones) Khobi, Rioni, Enguri, Supsa • Erosive coasts within lowstanding plains • Mountainous coasts with cliffs, small sandy or gravely beaches Main concerns of riparian countries – coastal erosion, recession of the coastline • Global and natural factors – 1) global changes and general sea level rise, 2) regional characteristics - shoreline morphology, elevation and geologic constitution, subsidence, neo-tectonic regime. • Anthropogenic factors – 1) changes hydrologic characteristics (water/sediment supply, regularisation of floods etc.), 2) men-made littoral structures as breakwaters, harbours etc. modifying littoral circulation; 3) uncontrolled use of beach material, 4) dredging of sand too close to the beaches or within the river mouth bars, etc. • Result - enhancement of coastal erosion, land losses, environmental changes and economic degradation of the coastal zone. Enguri r.Enguri-r.Khobi Enguri dam, Kulevi approach chanel Khobi r.Khobi-r.Rioni - Poti port, diversion of Rioni, change of the Rioni Poti port-r.Supsa Supsa mouth Supsa r.Natanebi-r.Kobuleti- abstraction of material from the beach Kintrishi Tsikhisdziri-Mtsvane Kontskhi – Batumi port, abstraction of material from beach; Mtsvane Kontskh-Makhinjauri - Batumi Chorokhi Batumiport cape-Chorokhi mouth – HPPs South to Batumi cape Volume of sediments carried in by the rivers 12000 Solid sediments 10000 Beachforming sediments 8000 42% reduction – solid 6000 sediments 4000 36% reduction – Volume, thou m3 Volume, beach forming material 2000 0 Natural conditions 2015 data Beach forming material balance 5000 Rivers, 3995 1970 2015 4000 Balance Balance 3000 1055 862 slope, 2000 150 150 Rivers,1332 1000 Underwater slope,Underwater Underwater Underwater 0 40 40 - - Inflow, thou Inflow, m3/year -1000 580 - , -2000 Wearing, Wearing, Wearing, Underwater Underwater -3000 Underwater Canyon Canyon, -2600 Shoreline recession Dune Beach Back of dune Sea Level Dune Beach Back of dune Sea Level Khobi delta Batumi Thank you .