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2025 ANNUAL GROUNDWATER MONITORING REPORT TEICHERT AGGREGATES AND GRANITE CONSTRUCTION VERNALIS AREA Water levels in the South Tracy#1 production well typically recovered to an elevation between 20 and 40 feet(msl)each winter until 2001,when increased pump operation made the measurement of static water levels difficult. Upon Teichert's initiative, plant staff measured static and pumping water levels in the South Tracy#1 well more frequently from late 2001 to 2008, and these supplemental data are tabulated in Attachment 2.Water levels in the South Tracy#3 production well were also monitored at a higher frequency. However, up until spring 2021,the sounding of water levels below a depth of approximately 271 feet was not successful due to an obstruction at this depth. Since spring 2021,the obstruction is no longer present, and water levels have been obtained. The Petz irrigation well, located west of the Teichert Vernalis plant, is completed in both the shallow and deep zones of the underlying aquifer system,and its water level hydrograph reflects a composite of these shallow and deep zones(see Attachment 1).The early water level record of this well (prior to 2000)shows groundwater level elevations between those observed in the discussed shallow and deep wells in the area.Similarly,seasonal fluctuations prior to 2000 appear to be a composite of observations made in the shallow and deep network wells.Specifically,seasonally high-water levels in this well rose from 72.46 to 86.58 feet(msl) between March 1994 and 1998,with seasonal fluctuations of almost 15 feet.Since then,water levels have been very similar to those observed in the shallow network wells.As of August 2022,this well is no longer accessible and has been removed from the monitoring network. Contours of equal groundwater elevations prepared with data from the shallow network wells show that the general direction of groundwater flow during times of seasonally high-water levels was typically to the east-southeast and east.This includes the first monitoring event in spring 1994 with comparatively high-water levels(Figure 10) and the period of the highest historically recorded groundwater elevations in spring 1998(Figure 11).The water level elevations in spring 2000 were relatively low compared to groundwater conditions observed in previous spring seasons, however,the predominant direction of flow was also to the east-southeast(Figure 12). In spring 2002, overall groundwater elevations were very similar to the spring 2000 elevations, but the groundwater flow direction was east-northeasterly as influenced by a relatively high groundwater level in the Koster irrigation well (Figure 13). The February 2025 (Figure 14) and December 2025(Figure 15)groundwater elevation contour maps indicate predominately easterly to northeasterly groundwater flow conditions. water elevation contour map indicates a predominately easterly groundwater flow condition. 4.2 Groundwater Quality The electrical conductivity(EC) of samples retrieved from the shallow network wells(Hall and Faulkner domestic wells) mostly ranged between 900 and 1,000 µS/cm between 1994 and the mid-2000's when EC values started to decrease until early 2014(Figure 16).The November 2014 EC measurement in the Faulkner well was the highest on record (1,130 µS/cm); Hall increased to 1,040 µS/cm.Since late 2015, EC decreased in both the Faulkner and Hall wells to values lower than early 2014. During 2025, EC in the Hall and Faulkner domestic wells ranged from 713 to 760 µS/cm.The EC of samples retrieved from the deep network wells South Tracy#1,#3,and Brown's New mainly range from 800 to 900 µS/cm and have LUHDORFF&SCALMANINI CONSULTING ENGINEERS 7