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Erosion of agricultural land and its importance for siltation and eutrophication of reservoirs in the Czech Republic
Krása, J. ; Jáchymová, B. ; Bauer, M. ; Dostál, T. ; Rosendorf, P. ; Hejzlar, Josef ; Borovec, Jakub ; Bečička, M.
In 58 large catchments of the Czech Republic (covering ca 35000 km2) the sediment transport processes were assessed. Amount of sediment flux into the streams and reservoirs from agricultural land was estimated. Sediment retention in all reservoirs was considered based on reservoirs‘ outflow. For thousands of small ponds the volumes and outflow had to be estimated based on reservoir areas and specific flow rates in catchments. The distributed approach allowed considering importance of particular agricultural fields for stream silting. The maps of annual sediment flow in all streams were derived. The sediment fluxes cause serious problems not only concerning eutrophication. For example Vltava river watershed up to Slapy dam (12 965 km2) exports 2.34 million tons of sediment by water erosion annually. 626 thousand ton is exported into the streams, and 615 500 t is then deposited in the reservoirs.
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Methodology for assessing ecological potential of heavily modified and artificial water bodies – a proposal
Borovec, Jakub ; Hejzlar, Josef ; Znachor, Petr ; Čtvrtlíková, Martina ; Blabolil, Petr ; Říha, Milan ; Matěna, Josef ; Kubečka, Jan
Methodology for the assessment of the ecological potential of heavily modified and artificial water bodies of the lacustrine type was developer, including also typology of water bodies. The selection of indicator metrics was based on statistical analyses of the sensitivity of each of the indicators towards the most significant stressor – eutrophication. According to these results, biological communities and their indicators were selected to comply with the requirements of the Water Framework Directive (2000/60/EC).
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Methodology for assessment of vulnerability of water reservoirs from eutrophication caused by supply of phosphorus from soil erosion
Krása, J. ; Dostál, T. ; Rosendorf, P. ; Hejzlar, Josef ; Borovec, Jakub
Vodní nádrže v ČR jsou dlouhodobě ohroženy eutrofizací (podmíněnou přebytkem dostupného fosforu), sedimentem a dále toxickými látkami (rozpuštěnými, ale často rovněž vázanými na sediment). S narůstající extrémností klimatu ve středoevropském regionu je v posledních letech zanášení nádrží ještě eskalováno. Za účelem celorepublikového posouzení rizika eutrofizace povrchových vod je řešen projekt QI102A265 „Určení podílu erozního fosforu na eutrofizaci ohrožených útvarů stojatých povrchových vod“. Metodika se skládá z několika částí: posouzení stavu trofie povrchových vod a ohroženosti nádrží; bilanční vyhodnocení jednotlivých zdrojů ve velkých povodích; kvantifikace erozního smyvu; kvantifikace transportu sedimentu do jednotlivých nádrží; určení celkového a rozpuštěného fosforu pocházejícího z eroze, resp. určení eutrofního potenciálu erozního smyvu. Stručně jsou zmíněna možná ochranná opatření proti vstupu erozního smyvu do nádrží.
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Assessment of vulnerability of water reservoirs to sediment loads and eutrophication caused by soil erosion
Krása, J. ; Rosendorf, P. ; Hejzlar, Josef ; Borovec, Jakub ; Dostál, T. ; David, V. ; Ansorge, L. ; Duras, J. ; Janotová, B. ; Bauer, M. ; Devátý, J. ; Strouhal, L. ; Vrána, K. ; Fiala, D.
This methodology has the following aims: Allow any investigator to evaluate the erosion and transport of sediment phosphorus in large river basins. Allow investigators to estimate the importance of erosion for the eutrophication of the target reservoir. Allow investigators to estimate the importance of other sources of phosphorus in the watershed. Allow investigators to estimate the behavior of the other tanks in the current state of phosphorus loads from the watershed. The methodology is focused on solutions in large river basins.
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Methodology for assessing ecological potential of heavily modified and artificial water bodies
Borovec, Jakub ; Hejzlar, Josef ; Znachor, Petr ; Čtvrtlíková, Martina ; Blabolil, Petr ; Říha, Milan ; Matěna, Josef ; Kubečka, Jan
Methodology for the assessment of the ecological potential of heavily modified and artificial water bodies was developed, including water body typology. The selection of indicator metrics was based on statistical analyses of the sensitivity of each of the indicators towards the most significant stressor – eutrophication. According to these results, biological communities and their indicators were selected to comply with the requirements set forth in the Water Framework Directive (2000/60/EC).
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