The 1.5 million gallon fuel plume located primarily on the Naval Base Point Loma has been contained and its boundaries identified, announced Capt. Mark Patton, the base’s commanding officer, at a Dec. 7 community meeting.
Six observation wells positioned just outside the federal property line confirmed that a finger of fuel product extending into La Playa affects only one home and does not continue further into the community, according to Patton.
“This is the first time we’ve been able to stand up in front of the public and say, ‘We know where all the boundaries of the plume are and we have contained it and we have checked any further movement of this plume.’ I can say that with about as much certainty as engineering standards would allow,” Patton said.
The Navy went public with the plume, which developed in 1999 with leaks from aging fuel tanks, in February after discovering that the jet and diesel fuel had unexpectedly migrated north toward La Playa. It was not until August, however, that one of two wells on the other side of the federal property line confirmed the plume’s presence in a residential area. Another four wells placed further from the base since September have not detected any fuel.
Patton said the Navy and contractor Shaw Environmental have also identified the cause of the plume’s curious movement northward and slightly uphill. He said detailed geophysical surveys of the land using seismic and electrical resistivity tomography found three inland underground features running parallel to San Diego Bay, one of which travels through the body of the plume and extends through the finger, as if creating a path for the petroleum. They were first considered to be fault lines, though further study has determined that they are most likely old shorelines.
“These are ancient shorelines buried deep underground that have different compositions “” sand or whatever the case may be “” and it allowed the plume to flow pretty freely to the north,” Patton said.
Also on hand to answer questions were representatives from Rep. Susan Davis’ office; the Defense Energy Support Center, which owns the fuel stored on the base; Shaw Environmental, the private contractor assisting with testing and surveys; and the Regional Water Quality Control Board, the state agency overseeing the Navy’s progress. District 2 Councilman Kevin Faulconer moderated the forum.
While the information provided at the town hall meeting was abundant, the attendance was poor, with less than 30 people present at the Portuguese SES Hall in Point Loma. The first widely publicized meeting on the subject in March drew a crowd of nearly 300.
“The fact that we had the low turnout was probably a combination of the holidays and the fact that, hopefully, the public has confidence in what the Navy is doing with this issue,” Patton said.
He emphasized that the current measures to contain and define the plume are in no way substitutions for extracting it; however, Patton noted that the surveys have helped create an accurate picture of the plume that will be critical for the Navy’s tank replacement project and corrective action plan.
The latter will consist of a 1,100-foot-long trench running the length of the plume at a depth of more than 50 feet. According to a representative from Shaw, it will be only a few feet wide, covered, filled with gravel and contain two to three pumps capable of draining large volumes. The enclosed trench will also collect vapors and will replace an existing 30-foot-deep rainwater “moat” that prevents runoff from reaching the bay.
Currently, dozens of 4-inch-wide recovery wells monitor the plume on the base and extract the fuel/water mixture in much smaller quantities. Patton said the trench will allow for quicker recovery, but admitted it could take more than a decade to completely clear the soil of fuel.
Product located off the base, as well as the extension of the plume closest to the bay, will be extracted through existing wells.
Patton said the recovery system would be operational before construction begins on the new tanks early in 2008. That project, which will replace the 27 aboveground and 23 underground tanks with 10 state-of-the-art mega-tanks, is almost fully designed.
Construction alone is expected to cost $140 million, up from $115 a few months ago due to the rising cost of materials; an additional $40 million has been budgeted for remediation of soil, security upgrades and environmental reports.
Completion of the new tanks is expected within two to three years, though emptying the old underground systems could continue until 2013, Patton noted.
In 1999, fuel began dripping from the bottom of one of the aboveground tanks. The petroleum continued to seep through the dry, rocky ground until it hit the water table 50 feet below, where it slowly spread laterally.
Sensors alerted officials to the first leak in 2000 and the Navy took one tank offline. Two more leaks were subsequently discovered in 2002 and 2003.
As one of the nation’s Strategic Petroleum Reserves, the submarine base stores roughly 42 million gallons of fuel on site for the Navy, Army, Marine Corps and Air Force.
The Navy’s PowerPoint presentation at the meeting is available at www.epointloma.com/plume. More information can be found www.cnrsw.navy.mil or www.house.gov/susandavis/fuelplume.html.