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This stream operating together with its environment can be thought of as forming a river ecosystem. River ecosystems are flowing waters that drain the landscape, and include the biotic (living) interactions amongst plants, animals and micro-organisms, as well as abiotic (nonliving) physical and chemical interactions of its many parts.
The theory is based on the concept of dynamic equilibrium in which streamforms balance between physical parameters, such as width, depth, velocity, and sediment load, also taking into account biological factors. [2] It offers an introduction to map out biological communities and also an explanation for their sequence in individual sections of ...
Ecohydraulics is an interdisciplinary science studying the hydrodynamic factors that affect the survival and reproduction of aquatic organisms and the activities of aquatic organisms that affect hydraulics and water quality. Considerations include habitat maintenance or development, habitat-flow interactions, and organism responses.
The amount of water lost by a plant also depends on its size and the amount of water absorbed at the roots. Factors that effect root absorption of water include: moisture content of the soil, excessive soil fertility or salt content, poorly developed root systems, and those impacted by pathogenic bacteria and fungi such as pythium or rhizoctonia.
Invasive plants and animals are a major issue to freshwater ecosystems, [29] in many cases outcompeting native species and altering water conditions. Introduced species are especially devastating to ecosystems that are home to endangered species. An example of this being the Asian carp competing with the paddlefish in the Mississippi river. [30]
The river's discharge at that location depends on the rainfall on the catchment or drainage area and the inflow or outflow of groundwater to or from the area, stream modifications such as dams and irrigation diversions, as well as evaporation and evapotranspiration from the area's land and plant surfaces. In storm hydrology, an important ...
The flow of a river can act as a means of transportation for plant and animal species, as well as a barrier. For example, the Amazon River is so wide in parts that the variety of species on either side of its basin are distinct. [19] Some fish may swim upstream to spawn as part of a seasonal migration.
Rapids cause water aeration of the stream or river, resulting in better water quality. [2] For a rapid to form, a necessary condition is the presence of a gradient, which refers to the river or stream's downward slope. When a river has a larger gradient, the water flows downhill faster. [3] Gradients are typically measured in feet per mile. [4]