期刊名称：Cuadernos de Investigación Geográfica = Geographical Research Letters
印刷版ISSN：0211-6820
电子版ISSN：1697-9540
出版年度：2018
卷号：44
期号：2
页码：641-658
DOI：10.18172/cig.3256
出版社：Universidad de La Rioja
摘要：This paper examines the effects of gravel mining on the suspended sediment transport in the Upper River Cinca (Central Pyrenees). Discharge, sediment transport and sediment grain-size distribution were measured, sampled and further determined in five monitoring sections along a 5-km river reach. Samples were taken at a section upstream from the mined area (i.e. reference section) and in four sections downstream (0, 200, 500 and 1500 meters). The results show that sediment concentrations downstream from the target site were up to one order of magnitude higher than in the reference section. Average concentrations during the impact were similar to those observed during floods, with maximum values attaining 6 g/l. Total load ranged from 2.2 to 17 Mg/day between sections; these values include the effects of the earth-moving works performed before the mining started. Concentrations at the lowermost section of the study reach were similar to those observed at the upstream reference section, suggesting that most of the suspended material was deposited in the channel. The transported material was coarse than that sampled under reference conditions; nevertheless, largest particles settled quickly, suggesting a selective transport downstream. This study constitutes a first step towards a better understanding of local sediment dynamics in rivers affected by maintenance works and related activities, such as gravel mining, and, overall, supports the comprehensive assessment of the effects of human actions on channel morphodynamics and the ecological functioning of mountain fluvial systems.
