Estimate of the eutrophication process in the Gruza Reservoir (Serbia and Montenegro)

The Gruza Reservoir (located at 238...269 m a. s. l., volume 64.6 center dot 10(6) m(3), surface 934 ha, drainage area 318 km(2), max. depth 31 m, mean theoretical retention time 22 months) was investigated during the years 1996 to 2001. The obtained values of trophic state parameters (9... 200 mu g L-1 total phosphorus, 3... 99 mu g L-1 chlorophyll-a, and 0.5... 2 m transparency) indicate that water of the Gruza Reservoir is eutrophic according to three types of classification: Carlson, OECD, and Jones and Lee. It was noticed that values of average biomass abundance are large in the Gruza Reservoir, and they could indicate a richer trophic state. When these indices are cited in connection with parameters of the trophic state, it is apparent that the Gruza Reservoir can be classified as a eutrophic water on the basis of total phosphorus content of chlorophyll-a and hypertrophic water with respect to transparency.