TULSA, Oklahoma - An error made during initial survey work for the Tulsa Zoo’s “Lost Kingdom” exhibit has added at least $158,000 to the cost and created a delay of almost six months for part of the project.

The Zoo said the overall exhibit will open on schedule in the spring of 2017.

The City of Tulsa said the issue was discovered during the summer, when a survey was done for the floor elevation of a pavilion. The mistake led to part of a slab being poured almost two feet below the correct level, and within a flood plain.

As a result, the slab had to be removed, part of the project redesigned and the slab was poured a second time.

The pavilion is one building within the larger project, and construction has continued while a dispute has developed over who is responsible for the mistake and which entity will pay for the error.

The Lost Kingdom exhibit covers five acres and will cost more than $20 million. It is being supported largely by philanthropic dollars, but taxpayers are paying part of the cost through the “Improve our Tulsa” bond package.

The City was processing a “change order” for the increased cost of the project, but that could potentially be recovered if a judgment is made against the contractor for the mistake.

City contractors are required to have a form of insurance that covers construction errors or failure to complete the project.