Archives - Page 2

  • Quantifying the Relation Between Electrical Conductivity and Salt Concentration for Dilution Gauging Via Dry Salt Injection
    Vol. 1 No. 2 (2017)

    Mark Richardson, Gabe Sentlinger, R.D. (Dan) Moore, André Zimmermann

    Salt dilution is a popular approach used for discharge measurement. This research focused on the procedure for determining the calibration factor (CFT) that is used to convert measured temperaturecorrected electrical conductivity to salt concentration for injection using dry salt. It is important to document the uncertainty in CFT because it contributes directly to uncertainty in the calculated discharge. Based on laboratory trials, it was found that the calibration should be performed as close to in situ stream temperature as possible to minimize errors. The discharge measurement and calibration procedure should be performed with the same probe to minimize uncertainty. Distilled water can be used instead of stream water for a calibration solution if an analytical correction is applied to account for differences in ionic composition of the water. The calibration factor can be determined with an uncertainty of less than ± 1% under “best-case” conditions, and the uncertainty may be as high as ± 4% under less favourable conditions. If calibration is not performed, CFT can be estimated from the relation between CFT and background temperature-corrected electrical conductivity (ECBG) with an uncertainty of about ± 2%, or estimated as a set value of 0.486 mg·cm·μS-1·L-1 with an uncertainty of about ± 2.8% for a properly calibrated probe. More testing should focus on streams with ECBG > 500 μS·cm-1, which were not well represented in this study.

  • Why Watershed Analysts Should Use R for Data Processing and Analysis
    Vol. 1 No. 1 (2017)

    R.D. (Dan) Moore, David Hutchinson

    Both the science and practice associated with watershed management involve the processing, presentation and analysis of quantitative information. In this article, the use of open source programming languages by watershed analysts is advocated. The R language, in particular, provides a rich set of tools for the types of data that are commonly encountered in watershed analysis. Theutility of R is illustrated through three examples: intensity-duration-frequency analysis of rainfall data, baseflow separation, and watershed delineation and mapping.

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