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Intermittent (or temporary) rivers cease to flow every year or at least twice every five years.〔(Tzoraki and Nikolaidis 2007)〕 Such rivers drain large arid and semi-arid areas, covering approximately a third of the earth’s surface.〔(Thornes, 1977)〕 The extent of temporary rivers is increasing, as many formerly perennial rivers are becoming temporary because of increasing water demand, particularly for irrigation.〔(De Girolamo, Calabrese et al. 2012)〕 The combination of dry crusted soils and the highly erosive energy of the rain cause sediment resuspension and transport to the coastal areas.〔(Tzoraki, Nikolaidis et al. 2009)〕 They are among the aquatic habitats most altered by human activities.〔(Moyle 2013)〕 During the summer even under no flow conditions the point sources are still active such as the wastewater effluents,〔(Perrin and Tournoud 2009; Chahinian, Bancon-Montigny et al. 2013)〕 resulting in nutrients and organic pollutants accumulating in the sediment. Sediment operates as a pollution inventory and pollutants are moved to the next basin with the first flush.〔(Bernal, von Schiller et al. 2013)〕 Their vulnerability is intensified by the conflict between water use demand and aquatic ecosystem conservation.〔(Webb, Nichols et al. 2012)〕 Advanced modelling tools have been developed to better describe intermittent flow dynamic changes such as the tempQsim model.〔(Tzoraki et al., 2009)〕 == References == * Bernal, S., D. von Schiller, et al. (2013). "Hydrological extremes modulate nutrient dynamics in mediterranean climate streams across different spatial scales." Hydrobiologia 719(1): 31-42. * Chahinian, N., C. Bancon-Montigny, et al. (2013). "Temporal and spatial variability of organotins in an intermittent Mediterranean river." Journal of Environmental Management 128: 173-181. * De Girolamo, A. M., A. Calabrese, et al. (2012). "Impact of anthropogenic activities on a Temporary River." Fresenius Environmental Bulletin 21(11): 3278-3286. * Moyle, P. B. (2013). "NOVEL AQUATIC ECOSYSTEMS: THE NEW REALITY FOR STREAMS IN CALIFORNIA AND OTHER MEDITERRANEAN CLIMATE REGIONS." River Research and Applications. * Perrin, J. L. and M. G. Tournoud (2009). "Hydrological processes controlling flow generation in a small Mediterranean catchment under karstic influence." Processus hydrologiques contrôlant la génération des débits dans un petit bassin versant Méditerranéen sous influence karstique 54(6): 1125-1140. * Tzoraki, O. and N. P. Nikolaidis (2007). "A generalized framework for modeling the hydrologic and biogeochemical response of a Mediterranean temporary river basin." Journal of Hydrology 346(3–4): 112-121. * Tzoraki, O., N. P. Nikolaidis, et al. (2009). "A reach-scale biogeochemical model for temporary rivers." Hydrological Processes 23(2): 272-283. * Webb, J. A., S. J. Nichols, et al. (2012). "Ecological responses to flow alteration: Assessing causal relationships with eco evidence." Wetlands 32(2): 203-213. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Intermittent river」の詳細全文を読む スポンサード リンク
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