"This project has been very technical and very complicated," Ralph Swenson told annoyed lawmakers on a Kingston Common Council panel in explaining the unprojected cost overrun.
Some lawmakers on the Finance/Economic Development Committee suggested the sinkhole had become a money pit.
The 23,000-cubic-foot sinkhole, caused by a deteriorating stormwater tunnel 85 feet underground, forced the closure of an intersection on a major Kingston thoroughfare for 18 months. It's now going to be closed at least six to nine months more, Swenson said.
The 2-mile-long tunnel underneath part of Kingston's Washington Avenue was built more than a century ago by New York City, 90 miles south of Kingston, during its construction of the Catskill Aqueduct. The 163-mile-long aqueduct brings drinking water to New York City from a reservoir about 15 miles west of Kingston.
The sinkhole -- now more than 75 feet long, 30 feet wide and 10 feet deep -- first appeared in March 2011 and was reported fixed by Kingston six months later, only to reappear the following March.
The latest repairs proposed by an outside geotechnical engineering services firm include building an arch over the tunnel to remove weight from its brick-arch roof and increasing the soil's strength and durability by changing its properties, Swenson said.
Some lawmakers expressed frustration about the high cost overrun and persistent delays due to the repair project's continuing failure to live up to expectations.
Committee Chairman Thomas Hoffay, a Democrat, said he had "zero confidence" Swenson's latest recommendations would be the last of the site's needed work, the Daily Freeman of Kingston reported.
Alderwoman Debbie Brown, also a Democrat, went so far as to suggest the city buy the homes in the affected area and abandon the repair project.
Some homeowners in the area have complained their walls and windows have cracked because of the sinkhole.