The use of electrical conductivity to develop temporally precise breakthrough curves in tracer injection experiments

JOURNAL OF HYDROLOGY

卷:588

Article

Scott, Isis S. P. C.¹  Huang, Chi-hua²  Bowling, Laura C.³ 

[1] Purdue Univ, Dept Agr & Biol Engn, W Lafayette, IN 47907 USA

[2] USDA ARS, Natl Soil Eros Res Lab NSERL, W Lafayette, IN USA

[3] Purdue Univ, Dept Agron, W Lafayette, IN 47907 USA

关键词: Solute transport;    Tracer study;    Tracer injection;    Electrical conductivity;    Phosphorus;    Linear model;   

DOI  :  10.1016/j.jhydrol.2020.124998

来源: Elsevier

【 摘 要 】

Tracer injection is a common technique in the studies of chemical transport in streams and channels. One of its limitations is the requirement of frequent sampling for representative tracer breakthrough data. Frequent collection and analysis of water samples are normally expensive and time-consuming. The measurement of electrical conductivity (EC) is a potential alternative to sample collection and analyses, because of its ease of data acquisition. But whether the EC value can characterize the injected solute concentration requires further evaluation. This article assesses the ability of EC to predict solute concentrations in tracer injections. Two injection studies were conducted in two separate flumes: an instantaneous injection of phosphorus (P) and bromide (Br) in a 20-m flume and a constant injection of Pin a 10-m flume. Water samples were collected intensively at multiple locations and EC was automatically and continuously recorded. Using a linear model, a solute breakthrough was calculated based on recorded EC and compared to the measured solute concentrations. The results showed that the EC-solute relationship can reduce the number of water samples needed for an accurate solute breakthrough. A small sample of paired recorded EC and solute concentrations can be used to build a model for each tracer study. By collecting at least 9 water samples at specific times, i.e., at shoulder, peak, and tail of a breakthrough curve, a simple regression model can efficiently predict P concentrations. The correlation is 80% or greater between predicted and observed concentrations, confirming that EC successfully traced P presence in water and can be used to facilitate tracer injection studies.

【 授权许可】

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