Evaluation of Nutrients and Chlorophylls Levels in Bovilla Reservoir of Tirana, Albania During 2006-2008

Abstract

Bovilla reservoir is formed only 14 years ago and since year 1998, is the main source (up to 1800 l/s) of drinking water for the city of Tirana and its suburbs (more than 850 000) inhabitants. The presence of various nutrients in excessive quantities in water can lead to eutrophication. Eutrophication is the major problem in public water supply reservoirs because it can cause in water treatment process. The effects of eutrophication can render the water body unsuitable for uses such as public water supply where a high standard of water quality is required. Depth profiles of nutrients and chlorophylls, which were carried on in Bovilla reservoir, during 2 years period from May 2006- May 2008 with 2 months frequency, are presented in this paper. Total phosphorus average resulted 4.85 μg/L; total phosphorus ranged from less than 2.0 to 14.7 μg/L during the study period. Higher total phosphorus values were reported in the water layer in contact with sediment bottom. The total nitrogen average resulted 248 μg/L; total nitrogen ranged from less 131 to 374 μg/L during the study period. Based on the total nitrogen:total phosphorus ratio phosphorus results to be limiting nutrient for lake primary production. Overall mean of peak values of chlorophyll a concentration resulted 3.2 μg/L, that is characteristic for oligotrophic level. The aim of the study was to collect sufficient baseline quality data to provide a basis for water quality protection and monitoring.