|
Stantec • •
<br /> Mr. Matthew Belair
<br /> May 23, 2012
<br /> Page 3 of 5
<br /> Spill History. The regulatory [40 CFR 112.1(b)] definition of a spill event is a discharge oil in quantities that
<br /> may be harmful, into or upon the navigable waters of the United States or adjoining shorelines. No spills
<br /> have occurred at the Site in the past five (5)years.
<br /> The worst case discharge planning volume for an onshore, non-transportation-related facility is defined in 40
<br /> CFR Appendix D as the capacity of the largest oil storage tank within a containment berm. In this case, the
<br /> largest oil container is the tanker truck having 4,000 gallon capacity. However, not all the oil from a
<br /> catastrophic failure of the tanker truck would be directed north towards Lone Tree Creek. The larger portion
<br /> of which would likely drain into the catch basins which are connected to Sump#1.
<br /> Facility has Contingency Plan. Delicato has and will continue to use the Contingency Plan that was
<br /> developed for responding to emergencies at the Site. Spills observed by the Security Officer on-site 24-hours
<br /> a day would be reported in accordance with the Contingency Plan.
<br /> Soil. At the request of the Board, three groundwater monitoring wells were installed west and down gradient
<br /> of the oil storage areas. The wells were installed for the purpose of evaluating soil conditions in the area
<br /> where expansion of the 20 acres of checks is planned. Installation of the wells was described in the
<br /> Monitoring Well Installations, Groundwater Sampling and Analysis, Delicato Vineyards, 12001 South Highway
<br /> 99, Manteca, CA, Kleinfelder, July, 9, 2001. Boring logs for the three wells (MW-1, MW-2, MW-3, see Figure
<br /> 5) indicate that although the top 10-feet of soil is sandy, there is a clayey silt layer beginning at about 10-feet
<br /> below ground surface (bgs) that is a 5-feet thick layer of stiff clayey silt at MW-1, a 19-feet thick layer of very
<br /> stiff clayey silt at MW-2, and a 10-feet layer of very stiff clayey silt at MW-3. The average depth to water
<br /> encountered during drilling of these wells is 35.18 feet below ground surface (bgs).
<br /> Three additional wells MW-4, MW-5, and MW-6 were installed in December 2008 for a similar purpose,
<br /> Monitoring Well Installation Report, Delicato Family Vineyards, 12001 South Highway 99, Manteca, CA,
<br /> December 9, 2008. The average depth to water encountered during drilling of these wells is 34.81 feet bgs.
<br /> In a June 12, 2008 letter to Mr. Timothy R. O'Brien of the Board, Robert S. Chrobak, Vice President of
<br /> Kennedy/Jenks Consultants, indicated that the hydraulic loading rates in the vicinity of MW4, 4,500 feet up
<br /> gradient of the oil storage areas was expected to be less than 0.5 inches per week. Board Order No. 96-077,
<br /> dated March 28, 1996, indicates a percolation rate of 4 inches per hour, using a gravel correction factor (i.e.,
<br /> 84 inches per week), in the disposal checks 1,000 feet north of the oil storage areas. At this rate of
<br /> percolation, contaminants would take up to five (5)weeks to reach groundwater at a depth of 34.81 feet bgs.
<br /> EVALUATION
<br /> Applicability of the SPCC Plan to the Site includes an evaluation of the above-stated requirements in the
<br /> areas of:
<br /> • Potential for Discharge
<br /> • Storage Volume, and
<br /> • Container Size.
<br /> Discharge Potential. The SPCC Guidance for Regional Inspectors, Version 1.0, US EPA, Office of
<br /> Emergency Management, Regulation and Policy Development Division, November 28, 2005 provided the list
<br /> of seven factors below for consideration in determining whether there is a reasonable expectation of
<br /> discharge to navigable waters in quantities that may be harmful. The applicability of each factor to the Site is
<br /> evaluated following its description.
<br /> Factor #1: Whether a past discharge of oil reached a navigable water or adjoining shoreline,
<br /> which indicates that another could be reasonably expected.
<br /> There is no record of such a discharge in the past 5 years.
<br />
|