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Draft Environmental Impact Report Page IV.F-7 Forward Inc. Landfill Expansion Groundwater recharge to the unconfined aquifer,both regionally and locally, is from local rainfall and stream infiltration, while the deeper, confined aquifers are recharged by rivers, reservoirs, and surface runoff along the western base of the Sierra Nevada. The project area is not in a General Plan-designated substantial groundwater recharge area, although some infiltration and percolation to the groundwater system is expected along the north and south branches of the south fork of Littlejohns Creek, as well as the Landfill's artificial recharge program.' Before the early 1960's, groundwater in the area typically flowed to the west. Since that time, heavy pumping in the Stockton area caused a northerly component of flow to develop. Salt- water intrusion from the west has resulted in a shift in pumping from west Stockton to east of Stockton, and a resulting modification in groundwater flow to the northeast. Based on groundwater elevation contours published by the San Joaquin County Flood Control and Water �^y Conservation District, the regional groundwater in the vicinity of the site is now typically 20 to fld� 30 feet below msl (approximately 60 to 80 feet below ground surface) and flows to the north- northeast. Beyond the trend of historical over-drafting (removing more groundwater than is naturally recharged)from the aquifer,the San Joaquin Valley's groundwater basins has been the tendency for water levels to show seasonally variations. Seasonal fluctuations reflect the rainy and dry seasons. Rainy season infiltration raises the water table, and dry season pumping lowers the water table. Seasonal fluctuations in the project area are on the order of 5 to 10 feet due to the distinct rainy and dry seasons. During the rainy season infiltration raises the water table and during the dry season drawdown by water well users lowers the water table. Groundwater within one mile of the project site is pumped by several existing irrigation and domestic wells. The locations of groundwater wells impacted or potentially impacted by the landfill related groundwater contamination plume is discussed in detail in below. Groundwater Wells in the area are used primarily to supply water for agricultural and domestic purposes. Of the facilities in the area, the California Youth Authority and the Northern California Women s Facility north of the Forward Landfill both have wells that are used to supply drinking water. Bottled water is supplied to all downgradient private well owners where volatile organic carbons (VOCs) are detected in their private wells. Two locations, associated with wells 8106A and 7898A, are supplied with bottled water by Forward. Water supply to the Forward/Austin units consist of Two water supply wells and one water supply standpipe are located at the existing Forward Landfill and one water supply well is located at the existing Austin Road Landfill. The water is used for dust control, compaction, and irrigation. The well at the Forward Landfill was drilled to a depth of approximately 135 feet and groundwater occurs at a depth of approximately 70 feet. The well was likely installed before the opening of the landfill, having been previously used for agricultural purposes. It is pumped at a rate of approximately 1500 gallons per minute at a maximum frequency of approximately eight times per hour. The water supply standpipe is located adjacent to the Forward scalehouse. The water production well that supplies the standpipe is located near the main entrance facility for the existing Forward Landfill. The other water supply well at the existing Forward Landfill is located south of the South Branch of Little Johns Creek and has a capacity of 500 gpm_ The water supply well at the existing Austin Road Landfill is located 2 Hydrogeological investigations at the nearby Forward Landfit]show that recharge along the course of the south fork of Littlejohn Creek,which crosses their property,has a significant influence on water table depth,gradient,and flow direction.