Considerations on reservoir sedimentation and heavy metals content within the Drenova reservoir (B&H)

Abstract

Reservoir sedimentation is a serious problem in many areas with high sediment yield. The main objective of this research is to analyse the storage capacity of Drenova reservoir and to determine the quality of water and sediment, particularly the content of heavy metals. Integrated GPS system and echo-sounder were used during the bathymetric survey in order to estimate sediment deposition in Drenova reservoir. The 2012 current state Digital Elevation Model (DEM) was compared to the preconstruction state DEM, which was compiled from geodetic bases and project documentation, thus enabling determination of all changes in the storage of Drenova reservoir. The results of this comparison showed that in the past 30 years, the storage capacity of Drenova reservoir decreased by 262,963 m(3) and 274,342 m(3) based on the normal and maximum water level. Drenova accumulation area is covered with 348,216 m(3) of sediment, which decreased the ineffective space by 69.64% and the total operational space by 5.81%. Water analysis of Drenova reservoir showed usual physical chemical parameters for these types of reservoirs and that it corresponds to maximum allowable concentration for the 11 class water level. The enrichment factor for metal concentrations showed that the anthropogenic influence is moderate for Ni and As, while it is minor for Cr, Cd, Mn, Zn and Cu, and it indicates no enrichment for Pb. The obtained results not only enabled defining potential locations for sediment desilting and its proper disposal in the basin, but led to consideration of other possibilities regarding duration span of Drenova reservoir.