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Page 6 Cabral-McAdams Property October 16,2006 Job No. 1828-092.02 relatively uniform. Subsurface soils to a depth of about 40 feet generally consist of tan silty sands/sandy silts, brown to red-brown fine sands, and red-brown slightly silty sands. Hydrogeology Surface Water The subject property is situated at an approximate elevation of 20 feet above mean sea level. The maximum site relief appears to be less than two feet, with the exception of an approximate ten-foot rise in elevation along a levee to the north. Natural topography in the immediate vicinity is generally flat and slopes gently to the west-southwest. Normal storm water generated on the subject property would generally infiltrate site soils; when these infiltration rates are exceeded surface water would likely follow the described west- southwesterly trend. The Calaveras River corridor is situated adjacent to and northerly of the subject property. Groundwater Historically, the groundwater flow direction in the Stockton area has been westerly from the Sierra Nevada toward the center of the Valley. Groundwater elevation data for the past decade obtained from the San Joaquin County Flood Control and Water Conservation District mapping indicate that the groundwater flow direction in the general site vicinity trends northerly toward a large regional cone of depression. Shallow groundwater typically is encountered within about 50 feet of ground surfaces within the vicinity of the subject property. Depending upon seasonal groundwater recharge, the proximity to surface water courses (Calaveras River) and nearby pumping, localized variations in the described depth and flow direction can occur. Recent subsurface investigation by our firm on the northerly and central portions of the property did not encounter groundwater within 20 and 40 feet below ground surfaces, respectively. FACTORS RELATED TO AIR PATHWAYS Communication with the California State Air Resources Board (ARB) has indicated that the ARB maintains daily records of weather conditions; however, recent data have not been compiled to calculate recent average temperature and precipitation, or average wind velocities and direction for the Stockton area. According to the Stockton California Resources Guide, the mean daily temperature and annual precipitation for the Stockton area is 63 degrees Fahrenheit and 13.95 inches per year, respectively. ARB meteorologist Mr. Gabriel Ruiz provided our firm with data indicating a predominantly west-northwesterly wind direction with a velocity averaging 4.37 miles per hour for the area. The most likely source of an airborne release risk for contaminated soils on the property would be from any future heavy earthwork equipment disturbing site soils. Contaminated soils on the property are generally within areas that would not be significantly disturbed by current farming activities.