Friday, February 19, 2010

Dredging Phase 1: GE Bucket Files and Analysis

Available for purchase as an MS Excel (.xls) file,
Dredging Phase 1: GE Bucket Files and Analysis
prepared by RAM TRAC Corporation; Project Manager,
Dr. Robert A. Michaels, PhD, CEP; copyright © 2010.

A two-day public meeting of the Hudson River PCB Dredging Peer Review Panel was held at the Gideon Putnam Hotel in Saratoga Springs, New York on Wednesday and Thursday 17-18 February. My oral comments to the Panel on Wednesday alluded to analysis of GE’s ‘bucket files’ (1), which are computer registers recording each closure of a dredge bucket in each delineated five-acre work unit (‘Certification Unit’, or CU) in the Phase I dredging area. From my analysis of these GE files I concluded that the preponderance of sediment disturbed by dredge buckets was left in mobile form on the river bottom, not placed in waiting barges.

The GE bucket files are available for free via download from GE's dredging website, as Table G-1 in Appendix G of GE’s draft Phase I Dredging Evaluation Report. The pdf format in which the 44-page file is provided, however, precludes numerical analysis of the data without extensive manipulation. To conduct my analysis, I converted the file into a Microsoft Excel (.xls) file. As the pdf version originally provided by GE contained built-in impediments to such conversion, the Excel version that I prepared represents the product of days of labor. The Excel version, therefore, is being offered for sale (click on the "Add to Cart" field at top right if you are interested).

The difficulty of converting the pdf file to an xls file existed because columns in GE’s 44-page pdf file were merged in different vertical patterns. They did not line up properly, therefore, when converted. Further, complete rows were merged within data columns, rather than at the end of each discrete data file. Other difficulties also were encountered.

To accomplish the conversion, I first converted the pdf file to MS Word (doc), and then pasted the doc file into an xls spreadsheet, which then turned out to be nearly 60 pages long. Next I unmerged and realigned the columns, and then deleted the merged rows. The resulting ALL DATA tab in the xls file provides the GE bucket file database in its (published) entirety, in its original published form, but now formatted in spreadsheets for numerical analysis. Indeed, in addition to the ALL DATA master spreadsheet, I created 11 separate tabs in the xls file (creatively labeled 1-11) for each data type, so that each parameter now is presented in one of the tabs, so it is more convenient to analyze statistically.

Using the bucket closure file (Tab 1) I analyzed the number of bucket closures in each five-acre dredging Certification Unit, and related this to separately-reported information about the volume of sediment placed in barges. This analysis is presented in the SYNTHESIS tab. Finally, I abbreviated this analysis by combining all CUs to create a BRIEF tab. The xls file that I generated from GE’s pdf version therefore consists of 14 component tabs, sequentially titled BRIEF, SYNHESIS, Tab 1… Tab 11, and ALL DATA.

The BRIEF tab summarizes the quantitative support for my oral statement that the preponderance of dredge-disturbed sediment is left on the river bottom, not barged.


1. GE. Phase I Evaluation Report: Hudson River PCBs Superfund Site. Draft report prepared for General Electric Company (Albany, New York) by: Anchor QEA (Glens Falls, New York) and Arcadis (Syracuse, New York); 191 pages plus tables, figures, and appendices; Appendix G, Table G-1, 44 pages; January 2010.