TITLE:
Assessment of the Trophic Status by Monitoring of Reservoir’s Water Quality
AUTHORS:
Milka M. Vidović, Marko N. Rodić, Marija U. Vidović, Ivana S. Trajković, Sanja Z. Jovanić
KEYWORDS:
Monitoring, Reservoir, Trophic State Index, Eutrophication, Cyanobacteria
JOURNAL NAME:
Journal of Water Resource and Protection,
Vol.7 No.1,
January
13,
2015
ABSTRACT: Continuous
long-term monitoring of aquatic systems is important for understanding their
complete evolution in order to monitor changes in the trophic status and water
quality. The continuous monitoring during a period of 20 years, by sampling
once a month at two locations, the water quality of reservoir “Grliste”, which
is used for the water supplying town Zajecar (Eastern Serbia), is observed and
developmental stages in the life of the reservoir were determinated. It should
be noted that the obtained results were used also in the purpose of finding a
cause of cyanobacteria bloom, as a consequence of algal production. Limiting
factors of algal production usually were nitrogen and phosphorus, however, in
this study, obtained results of subtraction between trophic state index,
calculated through total chlorophyll a (TSIChl-a) and trophic state
index, calculated through total phosphorus (TSITP), indicated that
limiting factor of algal production was light. On the basis of the
concentrations of dissolved oxygen (DO), total phosphorus (TP) and chlorophyll a (Chl-a) in the surface and in the
bottom, it was concluded that the reservoir passed through four development
phases during the examined period. Results of long-term monitoring showed that
in the first years after the formation of the reservoir, the highest trophicity
was detected (hypereutrophic status), but later the reservoir mostly maintained
eutrophic status.