The actual situation of the Tisza Valley traditionally used for land farming is basically determined by the consequences of the river regulation of the nineteenth century which aimed at the extension of the intensive ...The actual situation of the Tisza Valley traditionally used for land farming is basically determined by the consequences of the river regulation of the nineteenth century which aimed at the extension of the intensive agriculture, by the extreme water regime of alternating periods of flood showing a deteriorating trend and drought related to the climatic change; and by several environmental problems induced mainly by the land use. The objective of the article is to prove the regional advantages of a proposed technical solution to mitigate the flood risk with a special regard to the land cover. Hydrodynamic modeling results prove that the best technical solution is given by a combination of different strategies containing the inundation of deep floodplains-areas regularly covered by water before the river regulation works and, globally, by an important mitigation of flood damages, the costs of solution would be surely covered in the longterm. By means of its natural-resembling operation, the regular water cover would allow a multiple use of water, contributing to the solution of the simultaneously existing aridity problem, and, the development of the floodplain landscape management would help improve the ecological and the economical upgrading of the region.展开更多
The floodplain -egetation of the Tarim River in Northwest China is strongly influenced by irrigated agriculture. The abstrac- tion of river water disturbs; the natural dynamics of the floodplain ecosystem. The human i...The floodplain -egetation of the Tarim River in Northwest China is strongly influenced by irrigated agriculture. The abstrac- tion of river water disturbs; the natural dynamics of the floodplain ecosystem. The human impact on the hydrological system by bank dams and the irrigation of cotton plantings have caused adverse changes of the Tarim River and its floodplains, so the current stocks of the typical Tugai vegetation show significant signs of degradation. Field studies of soils and statistical analysis of soil moisture data have shown that the vitality of the Tugai vegetation is primarily determined by its position to the riverbank and the groundwater. There exist complex interactions between soil hydrological conditions and the vitality of the vegetation. But the availability of water is not only influenced by the groundwater level and seasonal flood events. The spatial distribution of stocks at different states of vitality seems also to be decisively influenced by physical soil properties. Our results show that the water supply of plant communities is strongly in- fluenced by the soil texture. Spatial differences of soil moisture and corresponding soil water tensions may be the decisive factors for the zonafion of vegetation. Physical soil properties control the water retention and rising of capillary water from deeper soil layers and the phreatic zone and may supply the root systems of the phreatophytic vegetation with water. Keywords： soil moisture;soil texture; soil water tensions; Tarim River; water retention展开更多
The water budget of the examined wetland was extremely variable in the past six years. Principally, it was affected by the water regime of the River Danube and the climatic factors. In order to investigate the changes...The water budget of the examined wetland was extremely variable in the past six years. Principally, it was affected by the water regime of the River Danube and the climatic factors. In order to investigate the changes of these elements, and to succeed to forecast, statistical methods by using SPSS program were performed. The time series of the evaporation, of the precipitation and of the river＇s water-level were analysed by linear regression, by exponential smoothing, by deterministic models. In consequence of the river regulation, the low-water and the mean stage of Danube were decreasing during the last hundred years, because the riverbed was permanently deepening. Since the river has overflowed its bed and has inundated to the wide floodplain, the decrease of high-water did not appear. The decline of the flooded days signed the quicker passage of flood. These processes have prevented that the examined wetland is going to fill up from the floods. The difference in summer semester between the evaporation and the precipitation was increasing during the last fifty years. Therefore, the drying out of the wetland is going to be more frequent in the future. In the interests of the survival of this wetland, it is necessary to construct the restoring-system in the floodplain.展开更多
The GEF-WB Nutrient Reduction project aims to reduce the phosphorus inputs of the Black Sea from the Danube by means of different interventions. Hungary takes part of this project by enhancing the nutrient trapping ca...The GEF-WB Nutrient Reduction project aims to reduce the phosphorus inputs of the Black Sea from the Danube by means of different interventions. Hungary takes part of this project by enhancing the nutrient trapping capacity of the Gemenc and Beda-Karapancsa wetlands （GBK） which can be found on the premises of the Danube Drava National Park along the Danube River in Southern Hungary. Due to anthropogenic influences, less of small floods reach the oxbows of the area than some decades before which has a negative effect on the ecosystem. The objective of the study is to predict the nutrient reduction capacity of the Gemenc-B6da-Karapancsa water system and to make a proposal to increase this capacity. Although the floodplain vegetation has a huge nutrient intake capacity, this is limited by the fact that the floodplain is not always covered by the water of the river Danube. For that reason, a combination of hydrodynamic modelling, flood probability calculation and an estimation of suspended solids settling constitute the base of this study. The main course taken into account is the settling of suspended solids and the ratio of total nitrogen and total phosphorus to the mass of sediment is determined by local measurement results.展开更多
文摘The actual situation of the Tisza Valley traditionally used for land farming is basically determined by the consequences of the river regulation of the nineteenth century which aimed at the extension of the intensive agriculture, by the extreme water regime of alternating periods of flood showing a deteriorating trend and drought related to the climatic change; and by several environmental problems induced mainly by the land use. The objective of the article is to prove the regional advantages of a proposed technical solution to mitigate the flood risk with a special regard to the land cover. Hydrodynamic modeling results prove that the best technical solution is given by a combination of different strategies containing the inundation of deep floodplains-areas regularly covered by water before the river regulation works and, globally, by an important mitigation of flood damages, the costs of solution would be surely covered in the longterm. By means of its natural-resembling operation, the regular water cover would allow a multiple use of water, contributing to the solution of the simultaneously existing aridity problem, and, the development of the floodplain landscape management would help improve the ecological and the economical upgrading of the region.
基金Under the auspices of Federal Ministry of Education and Research of Germany Project-Sustainable Management of River Oases along the Tarim River(No.01LL0918D)National Natural Science Foundation of China(No.31270742,31360200)
文摘The floodplain -egetation of the Tarim River in Northwest China is strongly influenced by irrigated agriculture. The abstrac- tion of river water disturbs; the natural dynamics of the floodplain ecosystem. The human impact on the hydrological system by bank dams and the irrigation of cotton plantings have caused adverse changes of the Tarim River and its floodplains, so the current stocks of the typical Tugai vegetation show significant signs of degradation. Field studies of soils and statistical analysis of soil moisture data have shown that the vitality of the Tugai vegetation is primarily determined by its position to the riverbank and the groundwater. There exist complex interactions between soil hydrological conditions and the vitality of the vegetation. But the availability of water is not only influenced by the groundwater level and seasonal flood events. The spatial distribution of stocks at different states of vitality seems also to be decisively influenced by physical soil properties. Our results show that the water supply of plant communities is strongly in- fluenced by the soil texture. Spatial differences of soil moisture and corresponding soil water tensions may be the decisive factors for the zonafion of vegetation. Physical soil properties control the water retention and rising of capillary water from deeper soil layers and the phreatic zone and may supply the root systems of the phreatophytic vegetation with water. Keywords： soil moisture;soil texture; soil water tensions; Tarim River; water retention
文摘The water budget of the examined wetland was extremely variable in the past six years. Principally, it was affected by the water regime of the River Danube and the climatic factors. In order to investigate the changes of these elements, and to succeed to forecast, statistical methods by using SPSS program were performed. The time series of the evaporation, of the precipitation and of the river＇s water-level were analysed by linear regression, by exponential smoothing, by deterministic models. In consequence of the river regulation, the low-water and the mean stage of Danube were decreasing during the last hundred years, because the riverbed was permanently deepening. Since the river has overflowed its bed and has inundated to the wide floodplain, the decrease of high-water did not appear. The decline of the flooded days signed the quicker passage of flood. These processes have prevented that the examined wetland is going to fill up from the floods. The difference in summer semester between the evaporation and the precipitation was increasing during the last fifty years. Therefore, the drying out of the wetland is going to be more frequent in the future. In the interests of the survival of this wetland, it is necessary to construct the restoring-system in the floodplain.
文摘The GEF-WB Nutrient Reduction project aims to reduce the phosphorus inputs of the Black Sea from the Danube by means of different interventions. Hungary takes part of this project by enhancing the nutrient trapping capacity of the Gemenc and Beda-Karapancsa wetlands （GBK） which can be found on the premises of the Danube Drava National Park along the Danube River in Southern Hungary. Due to anthropogenic influences, less of small floods reach the oxbows of the area than some decades before which has a negative effect on the ecosystem. The objective of the study is to predict the nutrient reduction capacity of the Gemenc-B6da-Karapancsa water system and to make a proposal to increase this capacity. Although the floodplain vegetation has a huge nutrient intake capacity, this is limited by the fact that the floodplain is not always covered by the water of the river Danube. For that reason, a combination of hydrodynamic modelling, flood probability calculation and an estimation of suspended solids settling constitute the base of this study. The main course taken into account is the settling of suspended solids and the ratio of total nitrogen and total phosphorus to the mass of sediment is determined by local measurement results.
