This map application presents the outputs from a project „Measures for diminishing agricultural non-point pollution sources for river basin plans“, commissioned by Vltava River Basin Authority, state enterprise. This project was prepared by a consortium, led by Research Institute for Soil and Water Conservation (VUMOP), with the partners Czech Technical University, Prague, SWECO Hydroprojekt and T.G. Masaryk Water Research Institute, during the years 2015-2019.

The project aimed to identify main pollution sources coming from surface (sediments from soil erosion and erosion-related phosphorus) and from subsurface runoff (especially nitrates and herbicides) leached by tile drainage, in the whole area of Vltava River Basin, (28 090 km²).

Non-point pollution sources still play a significant role in contamination of surface waters in the Czech Republic by the aforementioned substances. This contamination originates mostly from agricultural land, and, to a lesser extent, from forestry. The extent of arable land and its management has been recognized, besides point pollution sources, as the main factor influencing water quality of surface waters in small catchments. In the Czech Republic, the ratio of ploughed land, being for some catchments more than 70%, large field blocks, excessive land drainage, along with weather pattern, are the dominant drivers of sediment, nitrate and pesticide burden in small water courses.

The whole Vltava River basin was classified according to the degree of pollution risk in three categories across three hydrological units - water structure (tens of km²), fourth-order catchments (500 – 1500 ha) and subcatchments (50-100 ha). For selected, most vulnerable areas, the project is about to design (year 2019) appropriate measures on agricultural land, targeted to a particular field block, to decrease soil erosion, enhance water retention and to improve water quality (retention ditches and swales, balks, small water ponds, constructed wetlands, denitrifying bioreactors, targeted grassing, controlled drainage, etc.).

For soil erosion and pollution sources coming with overland flow, the project employed the Watem/SEDEM model, adjusted for the Czech conditions. Further, erosion-related phosphorus load coefficients were derived from direct measurements and landscape / riverbed characteristics.

Drainage flow and classification of nitrate load was assessed according to drainage characteristics – in relation to tile depth and spacing, location, specific drainage runoff and land-use characteristics in different soil/landscape zones.

The project assessed both pollution sources (surface and subsurface) separately, however, at the end, a synthesis was made in order to propose a hydrologically interconnected system of effective measures intended to strengthen the retention of water and improvement its quality in the agrarian landscape.

Authors

Research Institute for Soil and Water Conservation

Antonín Zajíček, Tomáš Hejduk, Petr Fučík, Tomáš Vojtěchovský, Eliška Kyzlíková, Zbyněk Kulhavý, Igor Pelíšek

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Czech Technical University in Prague

Tomáš Dostál, Josef Krása, Miroslav Bauer, Barbora Jáchymová, Jan Devátý

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Sweco Hydroprojekt a.s.

Martin Pavel

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T.G. Masaryk Water Research Institute

Pavel Rosendorf

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Vltava River Basin Authority, state enterprise

Tomáš Kvítek, Michal Krátký