Entering the third week after an oil spill was identified at the end of the trans-Alaska Pipeline, responders say that some oily water is still making its way into Port Valdez.
Kate Dugan, communications officer for the Alyeska Pipeline Service Company, which operates the trans-Alaska Pipeline, said that crews made major progress late last week in stemming the flow of oily water when they located a pipe that was discharging into the port.
“We couldn’t see the end of the pipe until at some point last week, and it turns out it’s some part of a historical preconstruction era piping system, so it wasn’t on my of the current drawings that we could find,” she said.
Crews found the system in historical diagrams of the area, said Dugan. Late last week, crews installed a treatment system, made up of three successive tanks from which the oil sheen at the top was skimmed.
But even after treating that oily water, Dugan said there is still a sheen in water being discharged into the port.
Though some oil is still getting into the port, Dugan said that responders have been able to reduce the total boomed area by about two thirds and that they are gradually decommissioning some of the response vessels.
It is still unclear how the water made its way from the sump, a four-foot-diameter, sixteen-foot deep tank, that overflowed after a pump malfunctioned, into the old underground piping system.
Dugan said that crews are still excavating around the area to try to determine the flow path of the oil in the ground.
“We have to do it systematically, we have to engineer and survey because there’s so much underground utilities and piping systems around the terminal so it’s challenging work,” she said.
Dugan said it might be weeks before Alyeska can complete an investigation to determine exactly what went wrong to cause the check valve in the sump and the pump to malfunction.
So far, over fifty thousand gallons of oily water have been recovered from Port Valdez from which 590 gallons of pure oil have been recovered. The final amount won’t be known until off-site metering is completed.
This article has been updated to clarify that while the cause of spill is clear, the exact mechanisms by which the check valve and pump malfunctioned won’t be determined until an investigation is complete.