Studies on harmonization and implementation of EU Water Framework Directive in Turkey were launched in 2011 by the Turkish Ministry of Forestry and Water Affairs (MoFWA). Within the scope of these studies river basin based biological monitoring surveys were initiated in 2012. In the early stages of biological surveys, common indices generally used in academic researches were used. However, these indices do not contain lots of species endemic to Turkey and were not tested whether they correspond to Turkish situation. Thus the resulting ecological status values were considered as inadequate in terms of their confidence and precision. In order to overcome these difficulties and to define the country specific biological indices, a Project on “Establishment of the Water Quality Ecological Assessment System Specific for Turkey” was initiated in 2014.
In this study, the most suitable biological indices for each biological quality elements and for each water body categories have been determined and adapted to Turkish conditions by using the inventory results of 25 river basins in Turkey and monitoring results in 8 river basins (Sakarya, Ceyhan, Kuzey Ege, Batı Akdeniz, Batı Karadeniz, Doğu Karadeniz, Aras basins and Aşağı Fırat sub basin) representing the different climatic and geographical conditions in Turkey. Within the scope of monitoring activities, 218 rivers, 69 lakes, 15 transitional waters and 31 coastal waters were monitored biologically, chemically and hydromorphologically for 4 monitoring campaigns. Moreover the potential reference sites and reference conditions in the 8 pilot river basins were defined.
As a result of this study, various biological indices were proposed to be used in Turkey. These indices are as follows: multimetric indices in rivers and lakes, Turkish Benthic Index (TUBI) in transitional and coastal waters for benthic macroinvertabrates; adapted Med-PTI in lakes, chlorophyll a and diversity indices in transitional and coastal waters for phytoplankton; Trophic Index for Turkey (TIT) for phytobenthos (diatoms); adapted IBI in rivers and lakes, adapted ELFI in transitional waters for fish fauna; IBMR in rivers, Lake Leafpacks 2 in lakes for macrophytes; EEI in transitional and coastal waters for macroalgae and angiosperm. Moreover, reference conditions of the reference sites in 8 basins, aquatic flora and fauna lists of the country, class boundaries for the proposed indices and ecological status of the 8 pilot basin were determined. This Project is recognised as an important step for establishment of the ecological assessment system in Turkey and the project guided MoFWA to define the next steps for finalising the ecological assessment system such as establishment of the reference monitoring network in 25 basins of Turkey, definition of type specific reference conditions for all types, definition of the ecoregions of Turkey in order to revise the typology system in Turkey.