Geologic Controls on Source Water Drive Baseflow Generation and Carbon Geochemistry: Evidence of Nonstationary Baseflow Sources Across Multiple Subwatersheds
Geologic Controls on Source Water Drive Baseflow Generation and Carbon Geochemistry: Evidence of Nonstationary Baseflow Sources Across Multiple Subwatersheds
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对源水的地质控制驱动基流生成和碳地球化学：多个子流域非平稳基流源的证据
DOI：
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发表时间：
2020
影响因子：
5.4
通讯作者：
Adina Paytan
中科院分区：
文献类型：
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作者：
C. M. Richardson;Margaret A. Zimmer;J. Fackrell;Adina Paytan
使用端元混合分析和与流域特征（例如地形、地质、土地利用和土壤特征）相关的方法，对加利福尼亚州沿海结构复杂的流域中六个不同大小的子流域在较长衰退期内的基流源的贡献和组成进行了量化。浅层地下水库和深层地下水库都是枯水期径流的重要贡献者，跨次流域基流源的组成与地质指标直接相关。底层基岩渗透率的二元分类（例如，低与高）最好地解释了季节性衰退期间浅层地下水和深层地下水输入的变化。使用溶解无机碳 (DIC)、溶解有机碳 (DOC) 和 254 nm 处的特定紫外吸光度 (SUVA254) 来进一步了解端元特性及其对基流的贡献。溪流水 DIC 浓度主要是通过地下水和浅层地下水端元的混合来控制，DIC 浓度相对恒定，而溪流水 DOC 浓度反映了浅层地下水 DOC 的空间和时间变化。本研究的结果表明（1）将基流视为多个水源的动态混合物的重要性，（2）低流量条件下地质对次流域尺度水源组成的影响，以及（3）基流水源变化对河流水溶解碳浓度的影响以及使用溶解碳浓度获得对基流水源时间变化的额外了解的效用。
The contributions and composition of baseflow sources across an extended recession period were quantified for six subwatersheds of varying size in a structurally complex watershed in coastal California using endmember mixing analysis and related to catchment characteristics (e.g., topography, geology, land use, and soil characteristics). Both shallow subsurface and deep groundwater reservoirs were important contributors for streamflow during low flow periods, and the composition of baseflow sources across subwatersheds was directly related to geologic indices. A binary classification of underlying bedrock permeability (e.g., low vs. high) best explained the changes in shallow subsurface water and deeper groundwater inputs through the seasonal recession. Dissolved inorganic carbon (DIC), dissolved organic carbon (DOC), and specific UV absorbance at 254 nm (SUVA254) were used to provide additional insight into endmember characteristics and their contributions to baseflow. Stream water DIC concentrations were broadly controlled by mixing of groundwater and shallow subsurface water endmembers with relatively constant DIC concentrations, while stream water DOC concentrations reflected both spatial and temporal changes in shallow subsurface water DOC. Results from this study show (1) the importance of considering baseflow as a dynamic mixture of water from multiple sources, (2) the effect of geology on source composition at the subwatershed scale during low flow conditions, and (3) the impact of shifting baseflow sources on stream water dissolved carbon concentrations and the utility of using dissolved carbon concentrations to obtain additional insight into temporal variability in baseflow sources.
影响因子：
11.6
作者：
Kindler, Reimo;Siemens, Jan;Kaupenjohann, Martin
通讯作者：
Kaupenjohann, Martin