The main objective of the study was to evaluate if macrophytes structure and trophic status of dam reservoir Kraśnik on a small lowland river Wyżnica are determined by phosphorous loadings. Studies were conducted seasonally in May, July and October during the years 2008-2009. Samples were taken at four sites: Site 1 - inflow of the Wyżnica River to pre-dam, Site 2 − pre-dam, Site 3 − dam reservoir and Site 4 - outflow of the Wyżnica River from dam reservoir. Physical and chemical parameters (temperature, Secchi disc depth, dissolved oxygen, pH, conductivity, total suspension, chlorophyll-a, TP and P-PO4) were measured in water samples. Together with water parameters there were estimated biomass of phytoplankton and species composition and biomass of emergent, floating-leaved and submerged macrophytes. Concentrations of TP, chlorophyll-a and Secchi disc depth were used to calculate trophic state index of Carlsson for dam reservoir and its pre-dam. Based on mean water current, mean residence time of water in dam reservoir and concentrations of TP and P-PO4 loadings (g m-2) flowing into dam reservoir with the Wyżnica River were calculated. The results showed visible negative effect of phosphorous loadings on both macrophytes composition and trophic state of the reservoir. The marked changes concerned soft vegetation. High P loadings (7.74 g m-2 of TP and 6.03 g m-2 P-PO4) during the spring of 2008 caused the disappearance of characeans meadows. In 2009, the presence of rigid hornwort (Ceratophyllum demersum L.), the species typical for eutrophic lakes was noted. This unrooted submerged plant uptakes dissolved orthophosphates directly from the water column.
Values of Carlsson index (51.4 ≤ TSI ≤ 68.2) indicate the eutrophic state of dam reservoir Kraśnik. During summer season in dam reservoir there were observed algal blooms (biomass of phytoplankton exceed 10 mg WW dm-3) and low water transparency (Secchi disc depth ranged from 0.4 to 0.65 m). During the two-year studies in dam reservoir Kraśnik a high reduction of P loadings, mostly dissolved orthophosphates was observed. Dependently on season, reduction of P-PO4 loadings ranged from 52% (July 2008) up to 91% (May 2009). The reduction of TP was lower and reached values from 15% (May 2008) to 48% (July 2009).
The study presents the results of the research into different phosphorus forms in the bottom sediments of anthropogenic limnic ecosystems i.e. the reservoirs of Pławniowice, Rybnik and Goczałkowice (SP). The bottom sediments of dam reservoirs were investigated by chemical extraction procedure for phosphorus forms. The lowest value of the mean AAP form percentage in the Pławniowice bottom sediments reflected the effect of reclamation with the hypolimnetic removal that had been conducted in the reservoir since 2003. The highest percentage of the RDP form (2%) was found in the Goczałkowice bottom sediments. The order of the specific speciation forms in the bottom sediments of the examined reservoirs was:
Rybnik: AAP > EP > WDP > RDP; 4,630> 3,740 > 117 > 65 > 3.5 mgP/kg
Pławniowice: AAP > EP > WDP > RDP; 916 > 783 > 107 > 15 > 1.4 mgP/kg
Goczałkowice: AAP > WDP > EP > RDP; 686 > 628 > 51 > 7 > 0.14 mgP/kg
The mutual correlations between the phosphorus speciation forms (AAP : EP : WDP : RDP) were as follows:
Rybnik: 1,323 : 1,068 : 33 : 18 : 1;
Pławniowice: 654 : 559 : 76 : 11 : 1;
Goczałkowice: 4,900 : 4,485 : 364 : 50 : 1.
The comparison of the mean concentration values for specific phosphorus forms in the bottom sediments of the three investigated reservoirs demonstrated that the Rybnik sediments had the highest contents of phosphorus. The contents in Pławniowice and Goczałkowice were 5-7 times lower
The research objective was to study temporal and spatial relations between specific phosphorus species as well as to examine total phosphorus content in the bottom sediments of an anthropogenic, hypertrophic limnic ecosystem Rybnik Reservoir, functioning under thermal pollution conditions. The chemical extraction procedure for the speciation of bioavailable phosphorus forms was used. It was found that available algae phosphorus was the most dominant phosphorus species in both sediment layers (83%), while the lower share was readily desorbed phosphorus form (0.1%). The phosphorus species concentrations depended on the organic matter concentration. The differences between phosphorus species contents in the upper (5 cm) and lower (15–20 cm) sediment core layers were low. The biologically active sediment layer extended from the sediment surface to at least 20 cm depth of the sediment core. Distributions of the concentrations within the year and at specific sampling points resulted from the variability observed for particular points and transformation intensity. Furthermore in the following study, the reaction rate constant for the increase and decrease in the concentrations of the phosphorus species in sediments was given. It was indicated that the speed of the phosphorus species transformations was affected by the environment temperature. In the heated water discharge zone (water temp. 17–35°C) the concentrations of selected speciation phosphorus forms increased more than in the dam zone (5–25°C). It was also found that the abundance of the bottom sediments with phosphorus species was related to the oblong and transverse asymmetry of reservoir depth.
The content of polycyclic aromatic hydrocarbons (PAHs) in water and sediments of the Blachownia
reservoir (South Poland) was investigated. Spatial variability of PAH concentrations in the longitudinal profi le of the
tank was determined. PAHs in samples were determined by gas chromatography coupled with mass spectrometric
detection (GC-MS QP-2010 Plus Shimadzu) using an internal standard. Concentrations ranged from 0.103 μg/L to
2.667 μg/L (Σ16 PAHs) in water samples and from 2.329 mg/kg d.w. to 9.078 mg/kg d.w. (Σ16 PAHs) in sediment
samples. A pollution balance was calculated and it was estimated that the infl ow load was 17.70 kg PAHs during
the year and the outfl ow load was 9.30 kg PAHs per year. Accumulation of about 50% of the annual PAH loads
(8.90 kg) is a threat to the ecological condition of the ecosystem. It was calculated that the PAH loads in bottom
sediment were about 80 kg, which limits their economic use. Improvement of the ecological status of this type of
reservoir can be achieved by removing the sediment. Analysis of the diagnostic ratios obtained for selected PAHs
showed that the potential sources of PAH emissions in small agricultural – forest catchments can be combustion
of a coal, wood, plant material (low emission, forest fi res, burning grass, etc.). Transportation is also signifi cant.
The Dez dam was commissioned in 1963 and since sediments accumulated in the reservoir up to an elevation of approximately 15m below the intake of the power tunnel. One of the possible measures to improve operation of the reservoir is by heightening of the existing dam. This paper describes the conducted procedure for static and thermal calibration of this 203m dam in Iran based on micro geodesies measurements. Also the nonlinear response of existing dam is investigated under maximum credible earthquake ground motions considering joint behavior and mass concrete cracking and safety of dam is evaluated for possible heightening. For thermal calibration of provided numerical model, transient thermal analysis was conducted and results were compared with thermometers records installed in central block. In addition, for static calibration; thermal distribution within dam body, dam self weight, hydrostatic pressure and silt load applied on the 3D fi nite element model of dam-reservoir-foundation were considered. Results show that the distribution of stresses will be critical within dam for heightening case under seismic loads in MCL.