Naturally Occurring Radon 222 as a Tracer for Streamflow Generation: Steady State Methodology and Field Example
Naturally Occurring Radon 222 as a Tracer for Streamflow Generation: Steady State Methodology and Field Example
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DOI：
10.1029/wr026i012p03065
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发表时间：
1990-12
影响因子：
5.4
通讯作者：
D. Genereux;H. Hemond
中科院分区：
文献类型：
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作者：
D. Genereux;H. Hemond
本文提出了一个定量的框架，使用天然存在的222 Rn作为水文流径示踪剂的条件下，稳定的径流。该方法由两个不同的部分组成，第一部分是确定R <$q，即给定河流河段供水的平均222 Rn含量。R <$q是通过测量222 Rn和两种注入的示踪剂（一种是保守的，另一种是挥发性的）在溪流中的浓度，并求解目标河段周围222 Rn的质量平衡方程来确定的。该方法的第二部分涉及使用R <$q值来确定河流流入的来源（以及，隐含地，在河流流量生成中重要的流动路径）。实现这一点的一种方法，简单的“地理源”分离，在这里介绍。在马萨诸塞州中部的比克福德流域进行的田间试验说明了这两部分的方法。所用的注入示踪剂为NaCl（保守）和丙烷（挥发性）。发现Rq值（700次衰变/分钟（dpm）/L）更接近包气带水的222 Rn含量（500 dpm/L），而不是饱和带水的222 Rn含量（2000 dpm/L），表明侧向非饱和流在研究场地的基流供应中很重要。
This paper presents a quantitative framework for the use of naturally occurring 222Rn as a hydrologic flow path tracer under conditions of steady streamflow. The methodology consists of two distinct parts, the first of which is the determination of R¯q, the average 222Rn content of the water feeding a given stream reach. R¯q is determined by measuring the concentrations of 222Rn and two injected tracers (one conservative, the other volatile) in the stream water and solving a mass balance equation for 222Rn around the reach of interest. The second part of the methodology involves using R¯q values to determine the sources of stream inflow (and, implicitly, the flow paths important in streamflow generation). One means of accomplishing this, simple “geographic source” separations, is presented here. Both parts of the methodology were illustrated with a field experiment at the Bickford watershed in central Massachusetts. The injected tracers used were NaCl (conservative) and propane (volatile). The value of R¯q (700 disintegrations per minute (dpm)/L) was found to be closer to the 222Rn content of vadose zone water (500 dpm/L) than to that of saturated zone water (2000 dpm/L), suggesting that lateral unsaturated flow was important in supplying base flow at the study site.