Mills, A. 2020. Comparison of two computational methods for estimating transmissivity based on the picking equation. Groundwater (this issue).

After the manuscript was approved for publication in Groundwater, I continued testing one of the two programs discussed in the paper (PPC‐Recovery). I found an error in the code that involved switching r_w for r_c in one equation, where r_w is the radius of the lower portion of the well, often screened and r_c is the radius of the upper part of the well, often cased. The code was corrected and the program version was changed from PPC‐Recovery35 to PPC‐Recovery38. When I applied PPC‐Recovery38 to the same data sets referenced in the above paper, the results were identical to those applied by PPC‐Recovery35 as reported. This is because all of those recovery tests applied to wells with r_c = r_w = 3.0 inches.

I applied PPC‐Recovery35 to the case of water‐level recovery of a well with differing r_w and r_c located in Ventura County, California (Kear 2005). The resulting computed transmissivity (T) value of 24 ft²/day (2.2 m²/day) was roughly one‐tenth of the value, 260 ft²/day (24 m²/day), that Kear (2005) derived from the original data using the Papadopulos and Cooper method (Papadopulos and Cooper 1967). Subsequently the corrected version of PPC‐Recovery, PPC‐Recovery38, was applied to the recovery portion of Kear's data with a resulting T value of 230 ft²/day (21 m²/day), differing by just 12% from Kear's value. This would seem acceptably close considering that on page 125 and on Figure 50 of Kear's thesis it implies that data from both the pumping period and the recovery period were used in the analysis, while the PPC‐Recovery38 was run using only the data from the recovery period.

The corrected program PPC‐Recovery38 should be used henceforth. It can be obtained from the Integrated Groundwater Modeling Center (IGWMC) at igwmc@mines.edu or by contacting the author at acmills2@comcast.net.

Mills，A.2020。比较两种基于拾取方程估算透射率的计算方法。地下水（本期）。

在手稿被批准在地下水中发表后，我继续测试了本文讨论的两个程序之一（PPC-Recovery）。我在代码中发现了一个错误，该错误涉及在一个方程式中将r _w切换为r _c，其中r _w是井的下部半径，通常经过筛选，r _c是通常情况下井上部的半径。程序代码已更正，程序版本从PPC-Recovery35更改为PPC-Recovery38。当我将PPC-Recovery38应用于上述论文中引用的相同数据集时，结果与报告的PPC-Recovery35所应用的结果相同。这是因为所有这些恢复测试均适用于r _c  =  r _w  = 3.0英寸的井。

我申请PPC-Recovery35到井的水位恢复的情况下，具有不同[R _W¯¯和[R _ç位于文县，加利福尼亚州（Kear 2005）。计算得出的24 ft ² /天（2.2 m ² /天）的透射率（T）值大约是Kear（2005）得出的260 ft ² /天（24 m ² /天）的十分之一。原始数据使用Papadopulos和Cooper方法（Papadopulos和Cooper 1967）。随后，将校正后的PPC-Recovery版本PPC-Recovery38应用于Kear数据的恢复部分，并得出T230 ft ² /天（21 m ² /天）的价值，与Kear的价值仅相差12％。考虑到在Kear论文的第125页和图50上，这暗示着可以接受抽水期和恢复期的数据，而PPC-Recovery38仅使用恢复中的数据运行，这似乎可以接受。期。

此后应使用更正后的程序PPC-Recovery38。可以从igwmc@mines.edu的地下水综合建模中心（IGWMC）获得，也可以通过acmills2@comcast.net与作者联系。