نتایج جستجو برای: water levels âand rivers
تعداد نتایج: 1435696 فیلتر نتایج به سال:
The aims of this study were to determine the microbial community in five rivers in the proximity of a city in the Czech Republic using 454-pyrosequencing, as well as to assess seasonal variability over the course of 1 year and to identify the factors influencing the structure of bacterial communities. Samples from five rivers around the city of Brno were obtained during four seasons and analyse...
Monitoring the variation of rivers and lakes is of great importance. Satellite radar altimetry is a promising technology to do this on a regional to global scale. Satellite radar altimetry data has been used successfully to observe water levels in lakes and (large) rivers, and has also been combined with hydrologic/hydrodynamic models. Except CryoSat-2, all radar altimetry missions have been op...
This chapter presents a range of key concepts that enable natural rivers to be understood as complex flows of water and sediment that interact and often result in changes to the channel shape. The implications for salmon fisheries and invertebrates are also considered. Rivers are linear features and so it might be supposed that the flow hydraulics would be unidirectional and relatively simple t...
Due to the acceleration of industrialization and urbanization in recent decades, the majority of coastal rivers and estuaries in China have been moderately or severely contaminated by a variety of pollutants. We investigated the spatial and seasonal variations of water nutrients (permanganate index, chemical oxygen demand, biochemical oxygen demand, ammonium, nitrate, total nitrogen, and total ...
Since the launch of ENVISAT satellite in 2002, the Radar Altimetry Mission provides systematic altimeter observations of the Earth surface. The ENVISAT Geophysical Data Records products contain, over all type of surfaces, altimeter ranges derived from four specialized retrackers: Ocean, Ice-1, Ice-2 and Sea-Ice retracker. Among the different goals of the ENVISAT Mission, one directly concerns l...
background: this study aimed to evaluate the pollution levels of surface water with heavy metals including pb, cd and cr in gheshlagh river, western iran. methods: water and sediment were sampled in five monitoring stations with three replicates in time along the river. the concentration of cr, pb and cd in both water and sediment samples were measured with graphite furnace atomic absorption sp...
introduction: water vapor spreads in molecular, unstable and erratic phase and transfers by convection and advection process. this transfer happens from the earth and oceans' surfaces to the atmosphere by the hot air. this type of this transfer is considered as the main pattern. in the studies of the atmosphere, one of the prominent factors to be considered is the complexity of water vapor...
China is experiencing from serious water issues. There are many differences among the Nine Major Rivers basins of China in the construction of dikes, reservoirs, floodgates, flood discharge projects, flood diversion projects, water ecological construction, water conservancy management, etc. The shadow prices of water resources for Nine Major Rivers can provide suggestions to the Chinese governm...
Pollution of surface water with harmful chemicals and eutrophication of rivers and lakes with excess nutrients are serious environmental concerns. The U.S. Environmental Protec‐ tion Agency (USEPA) estimated that 53% of the 27% assessed rivers and streams miles and 69% of the 45% assessed lakes, ponds, and reservoirs acreage in the nation are impaired (USEPA, 2010). In Mississippi, 57% of the 5...
Based on water quality monitoring data of four inflow rivers of Nansihu Lake in 2006, 2007 and 2008, the water qualities were evaluated according to the method of comprehensive water quality identification index, with the indicators of dissolved oxygen, CODMn, biochemical oxygen demand and ammonia nitrogen. The results show that the rivers has been in the state of serious pollution, in which th...
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