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十分重要，因为这种连通性在很大程度上受到世界各地人类活动的损害，例如取水和建造水库。干旱地区的人口约占全球人口的三分之一，面临着现有水资源无法满足用水需求的危险，对这些地区的水和沉积物通量进行评估是可持续水和沉积物管理的一个先决条件。旱地的水源集水区经常遭受严重侵蚀，造成水库沉淀和蓄水量损失，可能导致几十年内供水量大幅度减少。该项目将对旱地地区的径流和悬浮泥沙转移路径进行量化和建模。将对西班牙和巴西装有仪器的中尺度集水区的水和沉积物输送、接受和输送隔间之间的连通性过程进行分析，包括对转移路线和储存能力的分析。通过扩大多尺度实地监测、对渗漏和景观破碎化进行量化、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、储存和流动，将能增进对连通性的过程了解。现有的水和沉积物输运模型框架WASA-SED模型将得到扩展，以考虑山坡、河流和水库交汇处的这些现象。将在西班牙的Esera盆地和巴西的Upper Jaguaribe部分地区进行大规模试点参数化，以评估土地和水库管理的设想方案。预期结果将提高对旱地水和沉积物通量在与水和土地管理相关的空间尺度上的连通性过程的认识和建模能力。

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.