Attachment_7_-_Sample_Scenario.pdf

SP0600-13-R-0515

ATTACHMENT 7

SCENARIO:

(1) BACKGROUND: The site is a facility for the receipt, storage, and distribution of JP-8 although previously JP-4 and AVGAS were stored. Twelve field constructed underground tanks each with a capacity of approximately 3,500,000 gallons are used for storage. Fuel is transferred to, from, and within the facility via an underground pipeline network. A routine check of an existing monitoring well adjacent to one of the storage tanks indicates the presence of free phase hydrocarbon.

(2) SITE GEOLOGY: The regional geology in the area is characterized as claystone, siltstone and minor sandstone. Based on the monitoring well drilling logs, the sites subsurface lithology consists of colluviums up to 30 feet thick.

The colluvium grades into a highly weathered bedrock zone.

(3) HYDROGEOLOGY: Based on the groundwater measurements in the existing monitoring wells, two water-bearing zones are present: an upper shallow water-bearing zone, and a lower regional groundwater system. The upper water-bearing zone is contained within the weathered bedrock and fill around the tanks, and flows away from the tanks in a radial pattern generally following surface topography. Depth to shallow aquifer is 25 feet. A lower water-bearing zone, which is hypothesized as being recharged from the upper zone through joints and fractures, has been identified at a depth of 90’. Groundwater flow within the lower water system is generally to the north toward a tidal estuary that borders the site.

END OF SCENARIO