Intermittent river
Intermittent (or temporary) rivers cease to flow every year or at least twice every five years.[1] Such rivers drain large arid and semi-arid areas, covering approximately a third of the earth’s surface.[2] The extent of temporary rivers is increasing, as many formerly perennial rivers are becoming temporary because of increasing water demand, particularly for irrigation.[3] The combination of dry crusted soils and the highly erosive energy of the rain cause sediment resuspension and transport to the coastal areas.[4] They are among the aquatic habitats most altered by human activities.[5] During the summer even under no flow conditions the point sources are still active such as the wastewater effluents,[6] 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.[7] Their vulnerability is intensified by the conflict between water use demand and aquatic ecosystem conservation.[8] Advanced modelling tools have been developed to better describe intermittent flow dynamic changes such as the tempQsim model.[9]
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.