Revision History for SIR 2012–5154

Mark C. Kasmarek

Hydrogeology and Simulation of Groundwater Flow and Land-Surface Subsidence in the Northern Part of the Gulf Coast Aquifer System, Texas, 1891–2009

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Posted online July 31, 2012

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Revised and reposted November 14, 2012

Page 5:  On figure 2, the horizontal arrows that specify the Quaternary and Tertiary age extents were repositioned so that the Quaternary age ends
and the Tertiary age begins where the Chicot and Evangeline outcrops intersect.

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Revised and reposted December 2, 2013

The head results for stress period 129 (2060) for layer 4 (Jasper Aquifer) showed that an isolated area (37 cells located in San Jacinto County, Texas)
that is outside and beyond the primary area of interest had unacceptably low simulated head values. An evaluation of these cells showed that the model
contained hydraulic conductivity values that were two orders of magnitude for the 37 cells out of a total of 13,288 for layer 4.
       
The hydraulic conductivity of these 37 cells was increased by two orders of magnitude to approximately match values of hydraulic conductivity in adjacent
cells. The slight changes to these cells caused the root-mean-square error (RMSE) to increase from 23.3 to above 30.9 feet in layer 4, but the heads, flow,
and RMSE were unaffected for layers 1 and 2 (Chicot and Evangeline aquifers, respectively). To lower the RMSE of layer 4, additional modifications to hydraulic
conductivity of layer 4 were performed that decreased the RMSE value to 23.5. This slight modification to layer 4 required that 8 figures
(figs. 11, 21, 22, 25, 28, 29, 33, and 34) and 4 tables (tables 1, 2, 3, and 4) be modified, and numeric values shown in two sections of the report
(“Simulated and Estimated Water Budget Components” and “Summary”) required modification.