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Comparison of water quality on agricultural catchment in 1983 - 1985 and in present.
POKORNÁ, Zuzana
There are remarkable changes in water quality at the Jenínský stream catchment that lies in the Šumava foothills which were caused by change in land use. Two subcatchments, called J1 and J2, were monitored. In the first period 1983-1985, the two subcatchments were agriculturaly used, the land was fertilized and ploughed and cereals and corn were grown. In the second period 2004-2008, there were grasslands and the land was extensively used as pasture. This change in land use caused evident changes in water quality at the Jenínský stream catchment. The decrease of all monitored indices was remarkably seen in the concentrations of nitrate and ammonium. The average nitrate concentration in 1983-1985 was 39,5 mg . l-1, and decreased by 43,3% to the value of 16,9 mg . l-1 in 2004-2008. The greatest decrease of 85,9% was found in average ammonium concentration (0,4 mg . l-1 dropped to 0,05 mg . l-1). The positive effect of the change from arable land to grassland was confirmed and we can see it in the amount of nitrogen compounds and resulting improvement of water quality.
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Verification of application of factor analysis of water resources quality by maps
Ďurďová, Libuše
Chemistry development was assessed in locations where sulphate concentration increase exceeded 250 mg/l. For verification of layout physical and chemical water quality where composed maps in Arcview environment by method inverse distance weighted. Digital topological data vector maps ZABAGED in scale 1:10 000 were used. Evaluation of ground water chemistry development by application of factor analysis of physical and chemical water qualities was conducted.
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Impacts of climate change on the water quality in a dimictic reservoir
Růžička, Martin ; Hejzlar, J. ; Cole, T. M.
The study deals with prospective change in water quality in a reservoir caused by predicted climit change. Change of quality of the water on its way through watershed and reservoir was simulated by an modeling system consisting of a precipitation-runoff model,an empirical model of the river water composition and a hydrodynamic and water quality model of the reservoir processes.Boundary conditions for model were based on the 20-year real data series(1981-2000) and predicted climate characteristics according to the results of the contemporary global circulation models(GCMs).
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Flood situations influence on water quality in reservoirs controlled by means of mathematical modelling
Kafková, Dagmar ; Balejová, Marcela
Příspěvek se zabývá možnostmi matematického modelování pro sledování vývoje kvality vody v nádržích za běžných provozních podmínek i během extrémních povodňových situací se zvláštním zreželem na nádrž Pastviny na Divoké Orlici. Pro tuto nádrž byl upraven dvourozměrný matematický model CE-QUAL-W2, který se již dříve osvědčil při modelování nádrže Římov na Malši. Validaci modelu pro nádrž Pastviny nelze v současné době považovat za dokončenou, protože z předchozích let není k dispozici dostatečné množství bilogických a chemických dat, avšak bathymetrická data již odpovídají současnému stavu po vypuštění a vyčištění nádrže a model je připraven pro použití, jakmile budou potřebná data shromážděna.
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Model analysis of effects of hydrodynamics and nutrient loading to water-quality in a dimictic reservoir (Jordán)
Jarošík, Jiří ; Hejzlar, Josef ; Borovec, Jakub ; Růžička, Martin
The dynamic, two-dimensional model CE-QUAL-W2 was used to simulate recovery conditions in the eutrophic Jordan Reservoir. The aims were: (i) to calibrate the model and discuss differences between simulated and measured data; (ii) to use the calibrated model to determine the effects of external and internal phosphorus load and the depth of outlet on trophic conditions. After calibration the model reproduced thermal stratification, oxygen regime and concentrations of NO3-N with sufficient precision. Simulation of PO4-P was less exact. The results of mathematical simulation showed that (i) the required mesotrophic level cannot be accomplished without a significant decrease in inflow concentration of total phosphorus; (ii) the internal load of phosphorus is small and become insignificant after decrease of external load; and (iii) the use of bottom outlet is a potentially efficient method to partly decrease trophic level of Jordan Reservoir.
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