page_title: Geomorphology
section_title: Fluvial processes
hierarchical_section_title: Geomorphology / Processes / Fluvial processes
caption_attribution_description: English: Barchan dunes on Mars's Hellespontus region as seen by HiRISE on the Mars Reconnaissance Orbiter. These dunes are formed into a saif, a linear formation parallel to the direction of the wind. See File:Barchan in Noachis.jpg for a similar formation in Noachis Terra. Ελληνικά: Μηνοειδείς θίνες στην επιφάνεια του Άρη, στην περιοχή Hellespontus. Εικόνα από το τηλεσκόπιο HiRISE, στη διαστημοσυσκευή Mars Reconnaissance Orbiter της NASA.
context_page_description: Geomorphology is the scientific study of the origin and evolution of topographic and bathymetric features created by physical, chemical or biological processes operating at or near the Earth's surface. Geomorphologists seek to understand why landscapes look the way they do, to understand landform history and dynamics and to predict changes through a combination of field observations, physical experiments and numerical modeling. Geomorphologists work within disciplines such as physical geography, geology, geodesy, engineering geology, archaeology, climatology and geotechnical engineering. This broad base of interests contributes to many research styles and interests within the field.
context_section_description: Rivers and streams are not only conduits of water, but also of sediment. The water, as it flows over the channel bed, is able to mobilize sediment and transport it downstream, either as bed load, suspended load or dissolved load. The rate of sediment transport depends on the availability of sediment itself and on the river's discharge. Rivers are also capable of eroding into rock and creating new sediment, both from their own beds and also by coupling to the surrounding hillslopes. In this way, rivers are thought of as setting the base level for large-scale landscape evolution in nonglacial environments. Rivers are key links in the connectivity of different landscape elements.
  As rivers flow across the landscape, they generally increase in size, merging with other rivers. The network of rivers thus formed is a drainage system. These systems take on four general patterns: dendritic, radial, rectangular, and trellis. Dendritic happens to be the most common, occurring when the underlying stratum is stable (without faulting). Drainage systems have four primary components: drainage basin, alluvial valley, delta plain, and receiving basin. Some geomorphic examples of fluvial landforms are alluvial fans, oxbow lakes, and fluvial terraces.
caption: Seif and barchan dunes in the Hellespontus region on the surface of Mars. Dunes are mobile landforms created by the transport of large volumes of sand by wind.
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