Hydrological connectivity and its controls on hillslope and catchment scale stream flow generation

拟议项目是DFG 1598 CAOS研究组第一阶段项目G的延续。（包括其空间变异性和组织以及其时间动态）是推进水文理解以预测径流响应、溶质和物质输运以及水量和水质的流内变异性的中心主题之一。在这个项目中，我们将专注于山坡，河岸带和河流网络之间的功能连接，这是结构（静态）连接的空间模式如何转化为通量和水，沉积物和溶质的输出的结果。特别是，我们将推进的相关性和作用的理解，表面和地下过程和可能的反馈机制的扩散与通道连接。为了观察，理解和预测这些不同的功能连接从到达尺度的中尺度流域，我们将开发和应用一系列新的观察和建模技术，以测量功能连接在其适当的规模和必要的重复，得出统计上合理的结论。除了第I期（项目G）在嵌套集水区安排内的46个集水区和超过20个流量测量站所安装的宝贵设施外，我们建议安装100部延时摄影机和饱和度传感器，以追踪山坡对溪流网络的地表贡献，以及溪流网络本身的扩张和收缩。根据对溪流取样和地球物理观测的快照调查、近溪流和山坡测压计网络的连续测量以及山坡样带的选定示踪剂实验，将在从溪流到山坡样带的嵌套重点区域观测地下连通性。最后，流温度信号，这将是一个密集的网络监测的温度记录仪在整个阿特尔特盆地，将被用来作为山坡流连通性的指标，并作为示踪剂连续混合，但也将作为一个独特的数据集热平衡和热传输模型，这被认为是一个重要的对应模型的水流。该项目将对流域过程水文学和建模做出重要贡献，从而对CAOS研究单位做出重要贡献，因为对山坡-溪流连通性的系统评估对于将当地规模动态和径流生成与整体流域响应联系起来至关重要。因此，这种系统的评估连接，其时间动态，空间格局和基本控制将增加我们的理解景观组织的水流和运输，有可能大大提高区域化的努力。

The proposed project continues the work of project G within the first phase of the DFG Research Group FOR 1598 CAOS.Observing and understanding connectivity within a catchment (including its spatial variability and organization as well as its temporal dynamics) is one of the central themes in advancing hydrological understanding for predicting rainfall-runoff response, solute and matter transport and in-stream variability of water quantity and quality. In this project, we will focus on functional connectivity between hillslopes, riparian zones and the stream network, which is the result of how spatial patterns of structural (static) connectivity translate into fluxes and export of water, sediment and solutes. In particular, we will advance the understanding of the relevance and role of diffuse vs channelled connectivity for surface and subsurface processes and possible feedback mechanisms. In order to observe, understand and predict these different functional connectivities from the reach scale to the meso-scale watershed, we will develop and apply a range of novel observation and modelling techniques to measure functional connectivity at its appropriate scale and at the necessary repetition to draw statistically sound conclusions. In addition to the invaluable existing installations from phase I (project G) of 46 cluster sites and over 20 streamflow gauging sites within a nested catchment arrangement, we propose to install 100 time-lapse cameras and saturation sensors to track the surface contributions from hillslopes to the stream network as well as the expansion and contraction of the stream network itself. Subsurface connectivity will be observed at nested focus areas from the stream to a hillslope transect, based on snap-shot surveys of in-stream sampling and geophysical observation, continuous measurement in near-stream and hillslope piezometer networks and selected tracer experiments at hillslope transects. Finally, stream temperature signals, which will be monitored with a dense network of temperature loggers across the Attert basin, will be used as indicators of hillslope-stream connectivity and as tracers for consecutive mixing, but will also serve as a unique dataset for heat balance and heat transport modelling which is deemed to be an essential counterpart to the mere modelling of water flows. This project will make an important contribution to catchment process hydrology and modelling and hence to the CAOS research unit, as a systematic assessment of hillslope-stream connectivity is paramount to linking local scale dynamics and runoff generation to overall catchment response. This systematic assessment of connectivity, its temporal dynamics, spatial patterns and the underlying controls will thus add to our understanding of landscape organization of water flow and transport, with the potential to improve regionalisation efforts considerably.