WORK PLANS - Laserfiche WebLink

Home Browse Search

AEI Project No. 319400 • • May 22, 2013 Page 3 of 5 beneath the site, which appears to be laterally continuous across most of the site. An additional coarse sand layer was also encountered at 75 feet bgs. Based on a review of the USGS Union Island Quadrangle Topographic Map, the subject property is situated approximately eighteen (18) feet above mean sea level, and the local topography is relatively flat. The nearest surface water consists of an irrigation ditch and Sugar Cut (southern portion of Paine Slough) located approximately 0.33-mile to the northwest and 1-mile to the northeast, respectively. Based upon historical groundwater monitoring data, the direction of groundwater flow beneath the subject property is inferred to be to the northeast. Based on information obtained from CRA's Case Closure Summary—3725 Tracy Blvd, Tracy(April 2007), the depth to groundwater in the vicinity of the subject property was encountered between 4.7 to 18.5 feet bgs. 4.0 Scope of Work Drilling permits will be obtained from San Joaquin County Environmental Health Department for this investigation. The public underground utility locating service Underground Service Alert (USA) will be notified to identify public utilities in the work area. Private utility locating will be conducted an independent utility locating company to identify underground utilities on the property. A site-specific health and safety plan will be prepared, reviewed by onsite personnel, and kept onsite for the duration of the fieldwork. This work will be performed under the oversight of a California-licensed professional geologist. Drilling and Soil Sample Collection The scope of work proposed consists of the drilling and logging of a total of seven (7) borings at the property (Figure 2). The selected drilling contractor will hold a California C57 driller's license. Soil borings will be advanced with a truck-mounted direct-push drilling rig. The proposed boring locations, depths, and sample collection are based on the location of current USTs/fuel dispensers, and historical locations of hydraulic lifts. Locations of the borings may be altered based on the utility survey findings particularly if underground utilities are identified within the drilling areas and based on site access issues. The purpose of each boring is listed below: • Borings B-1 through B-4 will be advanced to a planned depth of 20 feet bgs in proximity to the USTs and dispensers. The borings will be advanced for the collection of soil and groundwater samples. • Borings B-5 and B-6 will be advanced in the area of the fuel dispensers. The borings will be advanced to a planned depth of 10 feet bgs for the collection of soil samples. • Boring B-7 will be advanced in the area of the former hydraulic lifts hoists. The boring will be advanced to the planned depth of 15 feet bgs for the collection of soil and groundwater samples.