Fluvial Dynamics Research Group (RIUS), University of Lleida, E-25198 Lleida, Catalonia, Spain(1); Forest Science and Technology Centre of Catalonia, E-25280 Solsona, Catalonia, Spain.
Fluvial Dynamics Research Group (RIUS), University of Lleida, E-25198 Lleida, Catalonia, Spain(1); Forest Science and Technology Centre of Catalonia, E-25280 Solsona, Catalonia, Spain.
Sci Total Environ. 2020 Nov 25;745:140884. doi: 10.1016/j.scitotenv.2020.140884. Epub 2020 Jul 17.
Mountain regions have a key role in the generation of runoff, and in the production and transfer of sediments to fluvial networks, especially in Mediterranean catchments where these processes are affected by marked changes in climate and land use (i.e. global change). This paper presents the water and the sediment budgets of the Ribera Salada (224 km), a meso-scale Mediterranean forested catchment located in the Southern Pyrenees. Field monitoring follows an integrated basins scheme (five nested sub-catchments), where hydrological and sediment transport data were collected continuously over a two-year period (2012-2013). Precipitation was obtained using radar images, which allowed the elaboration of rainfall maps used to characterize the spatial distribution of rainfall across multiple scales. Results indicate that the catchment is hydrologically divided in two areas which show contrasting fluvial regimes: the upper part of the catchment is considered wet and has a constant flow regime, supplying the majority of the water, while the lower part is drier, with ephemeral tributaries and water losses into the alluvial aquifer of the main river channel. In contrast to water yield, most of the suspended sediment load (i.e. 80%) is supplied by the driest part of the catchment where sediment availability was greater and where there is a greater connectivity between sediment sources and the channel network. The sediment yield of the whole catchment and the respective sub-catchments sits in the lower bounds of values reported for the Mediterranean region, indicating the generally low intensity of hydrological and geomorphic processes in the area. Once more the sediment budget approach matched to sound hydrological data proves efficient to characterize sediment dynamics in river basins, with special interest in areas such as the Mediterranean mountain catchments, where the effects of global change appear to be more acute.
山区在径流量的产生以及沉积物向河流网络的输送和迁移方面起着关键作用，尤其是在受气候和土地利用变化（即全球变化）显著影响的地中海流域。本文介绍了里贝拉萨拉达（224 公里）流域的水量和泥沙收支情况，该流域位于比利牛斯山脉南部，是一个中尺度的地中海森林流域。实地监测采用了综合流域方案（五个嵌套的次流域），在两年（2012-2013 年）的时间内连续收集水文和泥沙输移数据。利用雷达图像获取降雨量，绘制降雨图，用于描述不同尺度的降雨量空间分布特征。结果表明，流域在水文上分为两个区域，具有不同的河流特征：流域的上游被认为是湿润区，具有稳定的水流模式，提供了大部分水量，而下游较干燥，有短暂的支流，且大部分水流都渗漏到主河道的冲积含水层中。与径流量不同，大部分悬移质负荷（即 80%）来自流域最干燥的部分，该部分的沉积物供应较多，且沉积物源与河道网络之间的连通性更强。整个流域和各个次流域的泥沙输出量处于地中海地区报告值的较低范围内，表明该地区水文和地貌过程的总体强度较低。再一次证明，与可靠的水文数据相结合的泥沙收支方法，非常适用于表征流域的泥沙动态，特别是在像地中海山区这样的地区，全球变化的影响似乎更为明显。
