A relatively less polluted drinking water reservoir of Metropolitan Istanbul near the Black Sea coast

Located near the Black Sea coast of Turkey, Lake Terkos is one of the six m ain drinking water reservoirs of Metropolitan Istanbul, providing 25% of th e water demand. With very limited industrial activities and only 1% of its catchment area being devoted to settlements, it is a relatively less popula ted and comparatively less destroyed catchment of the metropolis, in contra st to other drinking water reservoirs of Istanbul, the water quality of Lak e Terkos is still of overall second class, implying that it can be used as a safe drinking water resource following a conventional water treatment sch eme. The most critical group of pollutants was determined to be nutrients, which somewhat exceed Class 2. Presently, phosphorous load is found to orig inate from point sources of domestic origin, whereas approximately half of the nitrogen load arises from forests and meadows. An appropriate managemen t strategy, concentrating especially on the future population densities, la nd use and an effective protection practice is needed to maintain the susta inability of the lake as a drinking water resource. (C) 1999 IAWQ Published by Elsevier Science Ltd. All rights reserved.