Читать книгу Introducing Large Rivers - Avijit Gupta - Страница 43

Large rivers are huge systems that transfer water and sediment from the continents to the oceans. Their nature and behaviour determine the morphology of their drainage basins, which are often subcontinental in size, as the entire drainage network is connected to these massive conduits. Thus large rivers may shape the physiography of the land surface over time.

Their location, morphology and behaviour depend on plate tectonics, regional and local geology, and large-scale climatic systems. Several of these rivers have existed for a long period, and all of them have been affected by the repeated climate and sea level changes in the Quaternary. The majority of large rivers are related to human habitation because of the availability of water, fertile fine-grained sediment, extensive floodplains, and ease of irrigation. Several floodplains and deltas have been anthropologically modified, even impounded, and altered from their natural forms and functions.

The following chapters highlight special cases of the morphology of large rivers, their long association with human civilisation, and their probable adjustments to the changing climate of the future.