Erratum

Abstract

GroundwaterVolume 58, Issue 5 p. 856-856 Erratum/Free Access Erratum This article corrects the following: Drawdown in a well of large diameter Istavros S. Papadopulos, Hilton H. Cooper, Volume 3Issue 1Water Resources Research pages: 241-244 First Published online: July 9, 2010 First published: 22 April 2020 https://doi.org/10.1111/gwat.13010AboutSectionsPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat 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 rw for rc in one equation, where rw is the radius of the lower portion of the well, often screened and rc 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 rc = rw = 3.0 inches. I applied PPC-Recovery35 to the case of water-level recovery of a well with differing rw and rc 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. References Kear, J. L. 2005. Hydrogeology of the Ojai Groundwater Basin: Storativity and Confinement, Ventura County, California. A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science on Geology. California State University, Northridge. Papadopulos, I.S., and H.H. Cooper Jr. 1967. Drawdown in a well of large diameter. Water Resources Research 3, no. 1: 241– 244. Volume58, Issue5September/October 2020Pages 856-856 ReferencesRelatedInformation