Problems on the new 520 bridge not only could wipe out the state’s reserve fund for the project, but also send it into the red.

New documents released Friday show that delays and the need to redesign pontoons could wipe out the final $100 million that’s left in the state’s $250 million reserve fund for the $4.18 billion project. Worse, it could cost another $128 million to fix the flaws.

And, the the project is now estimated to be completed in April 2016, 490 days late from its original completion date of the end of 2014. The state also said it only has money to continue to work on the project through mid-2014.

The bulk of the problem is due to design errors by the state Department of Transportation that results in cracks in pontoons and the need for costly fixes.

DOT spokesman Lars Erickson, a spokesperson for the department, said the $228 million costs are only “planning estimates” and that the state would negotiate any new costs with the contractors. The state’s estimates vary by as much as $36 million.

Complicating the state’s position is that the Legislature didn’t pass a new transportation package this year and lawmakers are uncertain if the new figures would help or hurt the state’s efforts in the future. The failed package contained an additional $100 million for the 520 project.

The new details about the additional costs came after KOMO News filed a public-records request. Previously, the state had been gone to releasing reports that didn’t include dollar figures.