Project E CONNECT - Longitudinal Patterns of SSF-Stream Connections

项目 E CONNECT - SSF-Stream 连接的纵向模式

• 批准号: 493884733
• 负责人: Dr. Theresa Blume
• 金额: --
• 依托单位: Helmholtz-Zentrum Potsdam - Deutsches GeoForschungsZentrum (GFZ)
• 依托单位国家: 德国
• 项目类别: Research Units
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/493884733?language=en
• 关键词: Project; CONNECT; Longitudinal; Patterns; SSF

Project E CONNECT aims at the identification of subsurface stormflow (SSF) contributions to the stream using distributed measurements in the riparian zone and in the stream, targeting specifically the landscape scale/reach scale patterns and controls of four different catchments.Identification of SSF occurrence at the hillslope is challenging because it is invisible as well as spatially highly variable due to a multitude of interacting controls and processes. However, actually identifying SSF contributions in the stream is an even greater challenge. Not only can the SSF signal be changed in the riparian zone, but once in the stream this signal can again be diluted or lost due to hyporheic exchange.We will tackle these challenges with a two-pronged approach: extensive experimental investigations in the riparian zone and the stream to identify SSF contributions and, based on this understanding, the development of pragmatic proxies and indices of SSF that can be used for catchment intercomparison studies. Our work will enable us to answer the following questions:1) What are the spatio-temporal patterns, controls and thresholds of SSF entering the stream?2) Do groundwater inflow patterns during baseflow differ from SSF inflow patterns during events?3) How strongly is the SSF signal modified within the stream towards the catchment outlet and what does this mean for hydrograph separation?4) Can we use proxies, such as near-stream wells, and hydrograph-based indices combined with catchment characteristics and hydro-meteorological drivers, to investigate the spatio-temporal variation in the occurrence of SSF? What are their uncertainties?We suggest an innovative experimental approach focusing on a mix of near- and in-stream indicators of SSF. We will combine automated sequential salt-dilution gauging, radon measurements and distributed temperature sensing with a monitoring network of near-stream wells and in-stream water level sensors. This will be complemented by an investigation of along-stream attenuation of the SSF signal and the resulting consequences for hydrograph separation. Building upon a framework of checks to identify the probability of SSF occurrence in time and space, we will develop a classification scheme which will help to assess the minimal data needs for an adequate signal observation and correct attribution which could be used in catchments where SSF cannot be studied in such detail. With the aim to simplify the determination of SSF contributions even more and facilitate catchment intercomparisons, we will assess the value of SSF indicators in streamflow hydrographs based on recession analysis. If successful, these indices will then be applied to long-term discharge time series for the test catchments to provide frequency distributions of SSF occurrence for the past decade. Due to the differences between the catchments, these distributions can be compared across a range of scales, topographies, geologies, and land uses.

项目E CONNECT旨在利用河岸带和河流中的分布式测量，特别针对四个不同集水区的景观尺度/覆盖范围模式和控制，识别地下风暴流对河流的贡献。识别山坡上的地下风暴流具有挑战性，因为它是不可见的，并且由于许多相互作用的控制和过程而在空间上高度可变。然而，实际识别流中的SSF贡献是一个更大的挑战。SSF信号不仅可以在河岸带改变，而且一旦进入河流，这个信号可能会再次被冲淡或由于潮汐交换而丢失。我们将通过双管齐下的方法解决这些挑战：在河岸带和河流进行广泛的实验研究，以确定SSF的贡献，并基于这种理解，开发可用于流域比较研究的SSF实用代理和指数。我们的工作将使我们能够回答以下问题：1)SSF进入河流的时空模式、控制和阈值是什么？2)基流期间的地下水流入模式与事件期间的SSF流入模式是否不同？3)SSF信号在河流中朝向集水口的变化有多大？这对过程线分离意味着什么？4)我们是否可以使用替代指标，如近流井，以及基于水文的指数，结合流域特征和水文气象驱动因素，来研究SSF发生的时空变化？它们的不确定性是什么？我们建议采用一种创新的实验方法，重点放在SSF的近流和流中指标的组合上。我们将把自动顺序盐稀释测量、氡测量和分布式温度传感与近流水井和溪流水位传感器的监测网络结合起来。此外，还将对SSF信号的沿流衰减及其对过程线分离产生的后果进行调查。我们将建立一个检查框架，以确定SSF在时间和空间上发生的可能性，从而制定一个分类方案，帮助评估充分观测信号和正确归类所需的最低数据，这些数据可用于无法如此详细地研究SSF的流域。为了进一步简化SSF贡献的确定和便于流域之间的比较，我们将根据退缩分析来评估SSF指标在径流过程线中的价值。如果成功，这些指数将被应用于试验流域的长期流量时间序列，以提供过去10年SSF发生的频率分布。由于集水区之间的差异，这些分布可以在一系列尺度、地形、地理和土地用途上进行比较。