WORK PLANS - Laserfiche WebLink

Home Browse Search

Approximately 143 DWR well logs have been collected for the property and the area within one mile of the property. These well logs were used to create a west-east trending cross section and a north-south trending cross section. The locations of these cross sections are presented on Figure 3 and the west-east and north-south cross sections are presented as Figures 4 and 5, respectively. The cross sections indicate that interbedded clay, silt, and sand deposits dominate the geology in proximity to the facility. Semi-continuous sand deposits approximately 5 feet in thickness are found at near surface depths of approximately 30 to 60 feet below ground surface (bgs). Thicker sand layers exist at greater than 60 feet in depth. Clay layers within 100 feet of surface are 10 to 30 feet in thickness and gravel interbeds are present at depth. REGIONAL HYDROGEOLOGY The regional ground water system in San Joaquin County lies within the San Joaquin Hydrogeologic Region,which is divided in to three subbasins-the Eastern San Joaquin, Tracy, and Cosumnes Subbasins. The Tracy subbasin is bounded by Tertiary and older sediments of the Coastal Range on the west and the San Joaquin River on the east. The Eastern San Joaquin Subbasin is bounded by the San Joaquin River on the west, the Mokelumne River on the North, the Stanislaus River to the south, and the crystalline bedrock of the Sierra Nevada Mountains on the east. The Cosumnes Subbasin is bounded by the Mokelumne River to the South, the Cosumnes River to the north, and the Sierra Nevada Mountains to the east. The Site lies within the Eastern San Joaquin Subbasin. This fresh water basin is defined vertically in depth by the extremely variable, interbedded Quaternary and modern alluvial deposits. With depth, three aquifer types are found. The shallow, near surface aquifer is an unconfined aquifer, underlain by a semi-confined aquifer, and a confined aquifer system within the Mehrten Formation. Differentiation between the unconfined, semi-confined, and confined aquifers is due to existence of clay layers within the Riverbank/Modesto and Laguna Formations. The interbedded nature of the alluvial sediments is significant. Ground water levels in nearby wells provided by the interactive DWR San Joaquin Valley web site (http://wdl.water.ca.gov/gwn indicate ground water elevations of approximately-15 to-20 feet MSL. Depth to ground water at the site is presumed to be 30 to 40 feet bgs. Woods Dairy March 1,2010 103-27 Monitoring Well Installation Plan 7 Revision 1