Evaluating Spatial and Temporal Dynamics of River-Floodplain Surface Water Connectivity Using Hydrometric, Geochemical and Microbial Indicators
Evaluating Spatial and Temporal Dynamics of River-Floodplain Surface Water Connectivity Using Hydrometric, Geochemical and Microbial Indicators
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DOI：
10.1029/2021wr030336
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发表时间：
2022-05-01
影响因子：
5.4
通讯作者：
Hall, Ed K.
中科院分区：
文献类型：
--
作者：
Brooks, Alexander C.;Covino, Tim;Hall, Ed K.
以水为媒介的连接景观组成部分的连接统称为水文连接。在河流-泛滥平原系统中，量化水文连通性是具有挑战性的，但能够描述由于基础地貌、气候和生物控制的复杂、不同种类的相互作用而产生的水文功能。在这里，我们使用现场指标来量化地表水水文连通性，并开发跨河流-泛滥平原系统的连通性强度度量。为了测量连通性强度，我们分析了水文数据、保守的示踪剂，以及跨溪流的自然发生的地球化学和微生物示踪剂。我们开发了水文连通性的经验模型，预测了各站点的每日连通性强值，并评估了连通性对径流变化的敏感性。一些泛滥平原地区始终与河流相连或断开，而另一些泛滥平原地区在整个季节表现出不同的连通强度。在断断续续连接的位置中，一些位置断开得很快，而另一些位置的断开阶段较长。在河流-滩涂系统尺度上，我们发现水文连通性总是随着径流的增加而增加，而跨系统连通性的差异在中间径流时达到峰值。具有间歇性地表连通性的洪泛区位置显示，水文连通性的年际变化是气候变化的结果。我们的结果表明，中间流是季节性连通机制的关键时期，需要了解气候变化对全流持续时间的影响，才能预测对河流-泛滥平原连通性的影响。
Water-mediated linkages that connect landscape components are collectively referred to as hydrologic connectivity. In river-floodplain systems, quantifying hydrologic connectivity is challenging yet enables descriptions of hydrologic function that emerge from complex, heterogeneous interactions of underlying geomorphic, climatic and biologic controls. Here, we quantify surface water hydrologic connectivity using field indicators and develop a connectivity strength metric across a river-floodplain system. To measure connectivity strength, we analyzed hydrometric data, conservative tracers, and natural occurring geochemical and microbial tracers across streamflows. We developed empirical models of hydrologic connectivity and predicted daily connectivity strength values across sites and assessed the sensitivity of connectivity to streamflow variability. Some floodplain areas were consistently connected or disconnected to the river, while other floodplain areas exhibited variable connectivity strength through the season. Of the locations with intermittent connectivity, some disconnected quickly and others had a prolonged disconnection phase. At the river-floodplain system scale, we found hydrologic connectivity always increased with streamflow while across-system variance in connectivity peaked at intermediate streamflow. Floodplain locations with intermittent surface connectivity demonstrated inter-annual variability in hydrologic connectivity as a function of climate variability. Our results suggest that intermediate flows are critical periods for seasonal connectivity regimes and understanding the influence of changing climate on full flow durations will be required to predict impacts on river-floodplain connectivity.