River delta

A satellite perspective of the river delta of the Lena river, Russia.
A satellite perspective of the Amazon Delta, in South America.
NASA A satellite perspective, in false color, the River Nile Delta.

A river delta is a triangular landform created by the deposition of the sediments that are carried by the waters of a river, where the river merges with a body of slow-moving water or with a body of stagnant water.[1][2] The creation of a river delta occurs at the river mouth, where the river merges into an ocean, a sea, or an estuary, into a lake, a reservoir, or (more rarely) into another river that cannot carry away the sediment supplied by the feeding river. Etymologically, the term river delta derives from the triangular shape (Δ) of the uppercase Greek letter delta. In hydrology, the dimensions of a river delta are determined by the balance between the watershed processes that supply sediment and the watershed processes that redistribute, sequester, and export the supplied sediment into the receiving basin.[3][4]

River deltas are important in human civilization, as they are major agricultural production centers and population centers.[5] They can provide coastline defence and can impact drinking water supply.[6] They are also ecologically important, with different species' assemblages depending on their landscape position. On geologic timescales, they are also important carbon sinks.[7]

  1. ^ Miall, A. D. 1979. Deltas. in R. G. Walker (ed) Facies Models. Geological Association of Canada, Hamilton, Ontario.
  2. ^ Elliot, T. 1986. Deltas. in H. G. Reading (ed.). Sedimentary Environments and Facies. Backwell Scientific Publications, Oxford.
  3. ^ Blum, M.D.; Törnqvist, T.E. (2000). "Fluvial Responses to Climate and Sea-level Change: A Review and Look Forward". Sedimentology. 47: 2–48. doi:10.1046/j.1365-3091.2000.00008.x. S2CID 140714394.
  4. ^ Pasternack, Gregory B.; Brush, Grace S.; Hilgartner, William B. (2001-04-01). "Impact of historic land-use change on sediment delivery to a Chesapeake Bay subestuarine delta". Earth Surface Processes and Landforms. 26 (4): 409–427. Bibcode:2001ESPL...26..409P. doi:10.1002/esp.189. ISSN 1096-9837. S2CID 129080402.
  5. ^ Schneider, Pia; Asch, Folkard (2020). "Rice production and food security in Asian Mega deltas—A review on characteristics, vulnerabilities and agricultural adaptation options to cope with climate change". Journal of Agronomy and Crop Science. 206 (4): 491–503. doi:10.1111/jac.12415. ISSN 1439-037X.
  6. ^ Anthony, Edward J. (2015-03-01). "Wave influence in the construction, shaping and destruction of river deltas: A review". Marine Geology. 361: 53–78. Bibcode:2015MGeol.361...53A. doi:10.1016/j.margeo.2014.12.004.
  7. ^ Hage, Sophie; Romans, Brian W.; Peploe, Thomas G. E.; Poyatos-Moré, Miquel; Haeri Ardakani, Omid; Bell, Daniel; Englert, Rebecca G.; Kaempfe-Droguett, Sebastian A.; Nesbit, Paul R.; Sherstan, Georgia; Synnott, Dane P.; Hubbard, Stephen M. (24 October 2022). "High rates of organic carbon burial in submarine deltas maintained on geological timescales". Nature Geoscience. 15 (1): 919–924. Bibcode:2022NatGe..15..919H. doi:10.1038/s41561-022-01048-4. S2CID 253145418. Archived from the original on 20 April 2023. Retrieved 19 April 2023.