Delta Water: Data Manipulation discovered in Contra Costa Water District Documents

March 21, 2015

The following graph has  been widely published by the Contra Costa Water District (CCWD) to make the case that the Delta was a historically fresh water swamp. You can find the document here and here. The graph is based on data from California Hawaiian Sugar Company. C&H Sugar used to have a massive sugar plant in Crockett, CA. Crockett is located right where the Carquinez Strait empties into San Pablo Bay. According to historical documents, C&H needed considerable fresh water in their sugar manufacturing process. Their fresh water was required to have a salinity level below 50 to 70 ppm. Thus C&H Sugar would send a barge into the Delta to collect fresh water. The barge would continue upstream until water was fresh enough to capture. This barge trip during the spring runoff was often quite short. On the other hand, during the fall when the Sacramento River flow was low, the trip was typically between 20 and 30 miles. The employees on the barge would record the number of miles to fresh water. C&H Sugar’s data is now used as a reliable estimate of Delta salinity conditions from 1908 to July 1920.

The graph appears to show a fairly stable ebb and flow of Delta fresh water flushing in the spring and Delta saltwater intrusion during the fall … until suddenly in 1919 – boom! Salt water intrusion instead of being stable between 23 and 27 miles each fall, in 1919 salt water was nearly 40 miles into the Delta. 1920 is the year that Antioch and other lower Delta water users sued rice growers in the Central Valley for taking so much fresh water during the dry season that no fresh water was left for downstream users. But is the CCWD graph accurate or has it been manipulated? I went back and got the actual C&H Data and compared it to CCWD’s representation of the same data.



I took the CCWD graph and compared it the C&H Sugar input into Excel and then placed the Excel graph on top of the CCWD graph and adjusted the graphs until achieving the best fit. In this manner we can graphically notice if there are significant differences. While the graphs match in most cases, it is also immediately obvious that CCWD has manipulated their representation of C&H Sugar’s Data. The first manipulation removed the 33.2 mile data point in 1908. I speculate the 33.2 data point manipulation occurred because numerous government and environmental groups in numerous documents attempt to make that case that fresh water was almost always present at Antioch prior to 1919. Antioch is very near 27 miles by river channel from Crockett. Can it be that a 1908 C&H Sugar data point recording salt water 6 miles beyond Antioch for the month of September doesn’t fit the CCWD narrative and so someone at CCWD changed the data?




The second manipulation occurs in 1911 and once again is in the direction of making the Delta appear fresher prior to 1919. These manipulations are not a result of filtering data because the majority of the graphs match. The manipulations are also not consistent with typographical errors. Further CCW’s document makes no notation to indicate that they have changed the C&H data, while they are still attributing the data to C&H Sugar.

Below is the actual C&H Data before the data manipulation





MH Reporter

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