Fine scale variations of surface water chemistry in an ephemeral to perennial drainage network
Fine scale variations of surface water chemistry in an ephemeral to perennial drainage network
复制标题
短暂到常年排水网络中地表水化学的精细尺度变化
DOI：
10.1002/hyp.9449
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发表时间：
2013
影响因子：
3.2
通讯作者：
T. Bullen
中科院分区：
文献类型：
--
作者：
M. Zimmer;S. Bailey;K. McGuire;T. Bullen
虽然在源头流化学的时间变化长期以来一直被用来记录基线条件和环境驱动因素的响应，很少注意到精细尺度的空间变化，可以产生线索的过程控制流水源。我们记录了空间和时间变化的水组成在源头集水区（41公顷）在哈伯德布鲁克实验森林，NH，美国。我们沿着沿着一个短暂的到常年的河流网络每隔50 m取样一次，并对不同水流条件下的渗漏和35口浅威尔斯井的地下水取样。在过去的研究中，地下水对该地区地表水的影响并不被认为是重要的，因为相对较粗的土壤被认为是在陡峭的集水区排水良好，径流响应迅速。然而，渗漏显示常年排放，上坡积累面积（UAA）小于那些渠道起始站点和较高的pH值，钙和硅浓度比流，这表明相对较长的地下水停留时间或长的地下水流路径不受地形划分。再加上大范围的地下水化学在威尔斯，这些结果表明，流化学变化反映了范围的连接，和质量，山坡水文土壤过程控制的地下水。溶质浓度的变化幅度在第一阶集水区看到的是广泛的，看到在第五阶哈伯德布鲁克山谷（3519公顷）。随着UAA的增加，溶质浓度的变化减少，这表明一阶流域的代表性基本面积（REA）值小于3公顷，而五阶流域为100公顷。因此，REA不一定是基本的集水特性。相反，高度可变的上游源和相对同质的下游特性之间的变化的分区可能有不同的物理意义，这取决于规模和复杂性的集水区的检查。版权所有© 2012约翰威利父子有限公司.
Although temporal variation in headwater stream chemistry has long been used to document baseline conditions and response to environmental drivers, less attention is paid to fine scale spatial variations that could yield clues to processes controlling stream water sources. We documented spatial and temporal variation in water composition in a headwater catchment (41 ha) at the Hubbard Brook Experimental Forest, NH, USA. We sampled every 50 m along an ephemeral to perennial stream network as well as groundwater from seeps and 35 shallow wells across varying flow conditions. Groundwater influences on surface water in this region have not been considered to be important in past studies as relatively coarse soils were assumed to be well drained in steep catchments with flashy runoff response. However, seeps displayed perennial discharge, upslope accumulated areas (UAA) smaller than those for channel initiation sites and higher pH, Ca and Si concentrations than streams, suggesting relatively long groundwater residence time or long subsurface flow paths not bound by topographic divides. Coupled with a large range in groundwater chemistry seen in wells, these results suggest stream chemistry variation reflects the range of connectivity with, and quality of, groundwater controlled by hillslope hydropedological processes. The magnitude of variations of solute concentrations seen in the first order catchment was as broad as that seen at the fifth order Hubbard Brook Valley (3519 ha). Reduction in variation in solute concentrations with increasing UAA suggested a representative elementary area (REA) value of less than 3 ha in the first order catchment, compared with 100 ha for the fifth order basin. Thus, the REA is not necessarily an elementary catchment property. Rather, the partitioning of variation between highly variable upstream sources and relatively homogenous downstream characteristics may have different physical significance depending on the scale and complexity of the catchment under examination. Copyright © 2012 John Wiley & Sons, Ltd.