Generation, transport and retention of water and suspended sediments in large dryland catchments: Monitoring and integrated modelling of fluxes and connectivity phenomena

了解水文系统的连通性很重要，因为世界各地的人类活动对这种连通性的损害程度很大，例如，取水和修建水库。特别是对于拥有全球约三分之一人口的干旱地区，面临现有水资源无法满足水需求的危险，对水和泥沙通量的评估是可持续水和泥沙管理的先决条件。旱地经常遭受水源集水区的强烈侵蚀，导致水库沉积和蓄水量损失，这可能导致几十年内可用水的大幅减少。该项目将对旱地地区的径流和悬沙输送路径进行量化和建模。将对西班牙和巴西的仪表化中尺度集水区的水和泥沙输送、接受和输送隔间之间的连通过程进行分析，包括对输送路线和储存能力的分析。扩大多尺度实地监测，量化渗漏和地貌破碎化，应用创新的沉积物追踪技术，以及通过遥感数据查明沉积物的主要来源、储存和通量，将有助于加强对连接过程的了解。将扩展现有的水和泥沙运移模拟框架WASA-SED模型，以解释山坡、河流和水库交汇处的这些现象。将对西班牙的埃塞拉盆地的部分地区和巴西的上Jaguaribe进行大规模的参数试验，以评估土地和水库管理方面的设想。预期结果将提高与水和土地管理有关的空间尺度上旱地水和泥沙通量连通过程的知识和模拟能力。

Understanding connectivity in hydrological systems is important given the degree to which such connectivity has been impaired by human activities worldwide, e.g. by water abstraction and reservoir construction. Specifically for dryland regions, which host about one-third of the global population and are exposed to the hazard that available water resources fail to meet water demand, the assessment of water and sediment fluxes are a prerequisite for sustainable water and sediment management. Drylands often experience strong erosion in headwater catchments, resulting in reservoir sedimentation and a loss of retention volume which can lead to a significant reduction of water availability within few decades. This project will quantify and model runoff and suspended sediment transfer paths in dryland regions. Connectivity processes between water and sediment delivering, accepting and transporting compartments, including the analysis of transfer routes and storage capabilities, will be analysed for instrumented meso-scale catchments in Spain and Brazil. Extended multi-scale field monitoring, the quantification of leakiness and landscape fragmentation, the application of innovative sediment tracing techniques, and the identification of major sources, stores and fluxes of sediments through remotely sensed data will result in an enhanced process understanding of connectivity. An existing modelling framework for water and sediment transport, the WASA-SED model, will be extended to account for these phenomena at the intersections of hillslopes, rivers and reservoirs. Large-scale pilot parameterisations for parts of the Ésera Basin in Spain and the Upper Jaguaribe in Brazil will be conducted to evaluate scenarios on land and reservoir management. The expected results will improve the knowledge and modelling capability of connectivity processes of water and sediment fluxes in drylands at spatial scales relevant for water and land management.