Most polluted city property: gas station cleanup will take more time and will cost more money

Final case closure for Yorba Linda's most contaminated city-owned property – the land beneath a gas station once located between the library and Imperial Highway just south of Lemon Drive – will be delayed another three years and could cost an extra $714,000.

That's the gist of a lengthy report prepared by Assistant City Engineer Rick Yee, who noted cleanup of leakage from underground tanks that contaminated groundwater near the site has already cost $1.775 million to remove more than 16,000 pounds of contaminate.

The delay for a process that was expected to be completed by the middle of this year is due to residual hydrocarbon contaminates found at two of the 17 wells that have been monitoring the cleanup on and near the fenced-off property since 2011.

The extra expenditure will pay for a “revised remedial approach,” according to Yee, which will involve “the use of chemical oxidation to expedite the removal process.”

He stated, “Such treatment process changes are not uncommon as certain technologies are more effective (in terms of cost benefit) once the higher concentrations of contaminate have been removed.”

The initial $1.775 million cost was covered by funds from the Orange County Transportation Agency pledged in 2012. The extra expense will be paid by $500,000 from the city's capital improvement budget and an additional $214,225 appropriation.

The new amounts could eventually be recovered from the state's Underground Storage Tank fund, since the site is eligible for up to $1.5 million in reimbursements, Yee noted, adding that “no official agreement between the city and state is in place....”

Yee stated that if state funds are not granted – “a low probability” – then other sources will need to be found, perhaps from the transportation agency again. Funds from city reserves “may be required” to “continue and finish the mandated cleanup effort.”

A new timeline has remediation concluding in 2018 “with approximately one additional year needed to pursue closure efforts of cycling the system on and off to verify that contaminate levels are not rebounding,” Yee explained.

After acceptance of final closure by both the Orange County Health Care Agency and the Santa Ana Regional Water Quality Control Board, the site can be redeveloped for retail or other commercial use, with a soil vapor barrier under a concrete pad probably required.

However, Yee reported, proceeds from a sale of the land or, if the city keeps the site, the appraised value would need to be reimbursed to the transportation agency, since the property was originally purchased with Measure M1 funds.

The city bought the land in 2004 as part of the then-controversial Imperial Highway widening and improvement project. A Superior Court judgment required the city to clean underground contamination that included a widening plume running under Imperial Highway toward a restaurant in the Yorba Linda Station Center.