AUSTIN (KXAN) — A tunnel that is supposed to protect parts of Austin from flash flooding is still not finished.

Projected estimates show it will be at least a year and a half until the tunnel out of Waller Creek will be finished. The underground tunnel is expected to remove 28 acres of downtown Austin from the flood plain, sending water into Lady Bird Lake.

Construction began in 2011, but has hit major delays as it was redesigned. Additional funds were needed in 2014, when work had to stop on the project after it was discovered it was too tall and blocking the Capitol View Corridor. Somehow that design flaw was missed by both city engineers and the city staff who approved the design.

The tunnel is also over budget. Back in 1998 Austin voters approved spending $25 million to built it. Since then, the cost has ballooned to more than $160 million. In May, the City Council approved another $7.5 million to finish the tunnel.

The contractor on the job also wants to be reimbursed for the costs. They say so far it has cost them $8 million in overhead to keep equipment on the construction site, and have their work force ready to go.

Council member Don Zimmerman said he was voting against the proposal for additional funds in May. “Well now it turns out that $6.2 million is completely gone and they are demanding another $7.5 million and I’m hearing the same argument – we have to pay the $7.5 million so we can finish the project then we’ll go to court to resolve the disputes over who is responsible for the cost overruns is it the city or the contractor,” says Zimmerman. “So this is Deja Vu.”

The Waller Creek Conservancy has a complete look at what the revitalization project will look like, here.

The tunnel is expected to be finished in May 2018, however the debris removal system within the tunnel should be complete by the end of this year.