RESPONSE OF A HYPERTROPHIC LAGOON TO RESTORATION AIMED WATER QUALITY MANAGEMENT EFFORTS AND INVESTIGATION OF FURTHER RESTORATION OPERATIONS TO ACCELERATE THE RECOVERY FROM EUTROPHIC CONDITIONS

Abstract

RESPONSE OF A HYPERTROPHIC LAGOON TO RESTORATION AIMED WATER QUALITY MANAGEMENT EFFORTS AND INVESTIGATION OF FURTHER RESTORATION OPERATIONS TO ACCELERATE THE RECOVERY FROM EUTROPHIC CONDITIONSErturk A.*, Gürevin C., Albay M.Istanbul University, Faculty of Aquatic Sciences ~ Istanbul ~ TurkeyCoastal lagoons are subjected to many pollution threads including organic matter loads, nutrient loads which may result in several water quality problems and environmental symptoms such as hypoxia or eutrophication, which eventually lead to loss of ecological functions and beneficial uses of the lagoon. Coastal ecosystems with a partly urban and partly rural drainage areas are subjected to a diversity of point and diffuse pollution sources such as domestic and industrial wastewater discharges, urban drainage outflows, runoff from rural settlements and agricultural areas. Küçük Çekmece Lagoon is a coastal lagoon locacated in Istanbul, one of the largest metropoles of Europe. It is deep enough for seasonal stratification. All of the watershed of lagoon is located in the province of Istanbul where 26% is located in the urban area and 74% is located in the rural area. The lagoon had been subjected to high nutrient and organic matter loads from late 70s through three main streams and reached a hypertrophic state. This long-term study analyzes the pollution and the progressing recovery of the lagoon from its eutrophic state for more than a decade from the year 2006 up today (2019) and proposes possible restoration techniques to accelerate recovery of the lake from its hypertrophic state.