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Degradation of small protected areas on the example of the Vrbenská tůň
URBANOVÁ, Jana
The natural monument Vrbenská tůň is located in České Vrbné on the northwest edge of České Budějovice. It is the remainder of the winding original stream Dehtářský potok in the wide flat alluvium of the Vltava river. This bachelor thesis provides information about eutrophication, the current state of flora and proposes measures for the conservation of this natural monument. I made a survey of flora in this locality, during the growing season of the year 2007 and 2008. A list of recorded vascular plant species and an overview of the characteristics of existing vegetation units are also included. The results are compared with the results of botanical research made in 2006. The conclusions of this work confirm that rapid silt deposition causes unstable vegetation with prevailingly strong and competitive varieties of plants.
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Concentrations and forms of phosphorus in the runoff from small agricultural catchments in the catchment of Orlík Reservoir
Richtr, J. ; Hejzlar, Josef ; Semančíková, E.
Concentrations of major P forms were monitored in the runoff from 21 small agricultural catchments with dominant arable land or grassland within the basin of Orlík Reservoir during one seasonal cycle. Mean concentrations of dissolved reactive P (DRP) and dissolved non-reactive P (DNP) were low and not differed at the arable land and grassland catchments (DRP 32 and 24 μg/l, DNP 8 and 9 μg/l, respectively). Particulate P (PP) concentrations varied significantly between these two types of catchments (77 and 20 μg/l, respectively). Apparently, PP did not originated from recent erosion of land surface but from sediment resuspension or bank erosion in streams. Significant relationships between P concentrations in oxalate extracts of upper (0–15 cm) and deep (50–70 cm) soil layers and between the phosphate saturation index in the 50–70 cm soil layer and the DRP concentration in runoff demonstrated existence of relationship between soil available P and P concentration in catchment runoff.
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Impacts of eutrophication on water quality in reservoirs: an assessment of nutrient inputs from catchment and of the anti-eutrophication resistance of reservoir ecosystem
Hejzlar, Josef ; Duras, J. ; Staňková, B. ; Turek, Jan ; Žaloudík, Jiří
The paper describes a methodology for the identification and quantification of nutrient sources in catchments (i.e. mainly point and diffuse sources, fishpond production, atmospheric deposition, natural background export) and for the determination of critical loads of reservoirs with nutrients, which are prerequisite for proposing of effective anti-eutrophication measures in reservoirs. An application of this methodology at the drinking water reservoir of Mostiště and its catchment showed that the results are in agreement with alternative methods of catchment nutrient sources assessment, e.g. ratio analysis among land use characteristics and stream water quality and/or direct determination of nutrient export from agricultural land with exclusion of other sources.
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Evaluation of sediment importance for phosphorus internal load
Borovec, Jakub ; Hejzlar, Josef
Eutrophication still belongs to the serious problems waiting for solution. Phosphorus is the nutrient most often limiting the primary producers. It is well known, the improvement of water quality can be, after successful decrease of external P load, retarded by P-release from sediments. It is also necessary to realize, that the decrease of external P-load to the demanding level cannot be due to technical, political or economical reasons always possible. Measures increasing P-retention in sediments are often employed in such conditions. Many cases are known when the level of the water quality improvement remained far behind the expectations. Technical problems, still unknown mechanisms or insufficient screening followed by inadequate solution might be the reasons for the failures. The aim of this paper is to show simple decision-support system for exclusion of improper solutions and increase of the effectiveness of activities made before the rehabilitation measures realization.
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