Interstate 526 has two more financial hurdles, and several environmental ones, before work can begin on the controversial road across Johns and James islands.

On the financial side, a state committee must approve the final funding for the project, which has an estimated total cost of $558 million. And Charleston County must determine if money is available to compensate an estimated 3,082 property owners who live within 1,000 feet of the proposed road for a drop in the value of their property. On the environmental side, legal challenges to permits could delay the project for years.

Debra Rountree, director of operations for the S.C. Transportation Infrastructure Bank, said the final $130 million to $150 million for the project must be approved by the state’s Joint Bond Review Committee.

That group could consider the matter soon, possibly at its next meeting, which likely will be held in early May. The Infrastructure Bank in August approved the additional funding for the project, she said. But the committee must give final approval to the additional money. Rountree said she can’t recall the Joint Bond Review Committee turning down an Infrastructure Bank request.

State Rep. Chip Limehouse, who is a member of the Joint Bond Review Committee, said the additional money “will get scrutiny and some attention and evaluation.” But, he said, “at the end of the day, I expect it to advance.”

The Charleston Republican also is a member of the Infrastructure Bank board, and a strong supporter of the completion of I-526.

The Infrastructure Bank probably won’t be borrowing money by issuing bonds for the final piece of funding for the road as it will for the initial $420 million, Rountree said. Instead, it will cover that cost from other bank revenue that it expects to receive after 2020. But the bank still must get approval from the Joint Bond Review Committee, even it if it isn’t planning to issue bonds.

The other financial hurdle involves compensation to people living within 1,000 feet of the road.

Charleston County Council in December narrowly approved moving forward with I-526 with a 5-4 vote. Councilwoman Anna Johnson was swayed to cast one of the deciding votes in part because of an amendment she proposed that required the county to put forth “a good faith effort” to compensate people who live within 1,000 feet of the road for the impact it would have on their property. County officials last week said they have tentatively identified 3,082 parcels within 1,000 feet of the road’s proposed path. But they haven’t yet come up with an estimate on how much such compensation would cost or whether the plan can be carried out.

County Council Chairman Teddie Pryor said he thinks it’s premature to be talking about the future of the project because it’s still in the planning stages. And while the road’s general route is known, its exact path is not, he said. Until the exact path is known, it doesn’t make sense to talk about the compensation plan.

Jake Libaire, a project manager for the Coastal Conservation League, an I-526 opponent, said he thinks the Joint Bond Review Committee should not approve the additional money for the project because I-526 is not ranked a state priority. “This project would put the state in jeopardy by expending vital road funds on a low-priority project,” he said.

His group also likely will appeal environmental permits that must be in place before construction begins, he said. The road would require filling sensitive wetlands, and likely would promote development, he said. The costs to the environment are far too high compared to any benefit the road might bring. “This is a classic example of induced growth,” Libaire said. “The infrastructure will enable sprawl.”

Reach Diane Knich at 937-5491 or on Twitter @dianeknich.