Concrete infrastructure is shown outside Sports Pavilion Lawrence at Rock Chalk Park.

Lawrence City Hall officials are acknowledging that an audit report that gave the city glowing reviews on the controversial Rock Chalk Park project has errors related to concrete used in the no-bid construction project.

But city officials, after reviewing additional documentation in their files, said they were confident the errors would not change the report’s main finding that city taxpayers had gotten a good value.

“What I want the public to know is we looked at all of the batch tickets we have in our possession and they show that more concrete was delivered than what we paid for, and we paid appropriately for what was actually installed,” City Manager David Corliss said.

The city still has an approximately $1 million payment due to the infrastructure contractors on the project, but Mayor Mike Amyx said he wants more information about the latest questions before placing the payment on a future city agenda.

“It is important to me that we defer the final payment until we can say we understand every bit of this,” Amyx said.

Questions about the audit by Tennessee-based McDonald & Associates came to light after the Journal-World conducted a brief review of the working papers of the city-hired auditor, who delivered his report on Monday. The Journal-World found several questionable numbers or entries in a spreadsheet that provided information about concrete deliveries made to the Rock Chalk Park site. Among the findings:

• The spreadsheet showed that there were at least eight deliveries of concrete made to the Rock Chalk site for infrastructure work in January 2014. But a previous infrastructure report written by city engineers clearly stated that no infrastructure work took place during January due to the cold weather.

• The spreadsheet showed 20 deliveries of concrete that listed the use of the concrete for footings, “tiltups” or walls. Those are terms normally associated with the construction of a building, not the construction of infrastructure such as roads, parking lots and utility lines. The timing of those deliveries also occurred at the same time walls, footings and tiltup walls were being poured for the adjacent city recreation center. City officials believe those delivery tickets were incorrectly included in the documents for the infrastructure work. City officials have worked to keep infrastructure and recreation center costs separate. The city is paying for the recreation center through a $10.5 million construction contract. Any recreation center costs that show up in the infrastructure project would artificially inflate the true cost of the infrastructure.

• City officials acknowledge that the auditor was given an incomplete set of delivery tickets to review. Public Works director Chuck Soules said it wasn’t until after the audit that it was realized another batch of tickets — consisting of several hundred tickets — was being stored at a separate location at City Hall and had not been given to the auditor.

• The auditor attempted to calculate how much concrete would need to be used to build the infrastructure as called for in the development agreement that the city has with Kansas University Endowment Association and the private development firm Bliss Sports II. But the calculations of the auditor greatly underestimated the amount of concrete required. Instead of using actual specifications listed on approved plans, the math indicates he made an assumption for calculation purposes that all concrete used at the site would be poured to a depth of four inches. Warren Hudson, the lead auditor for the project, did not return a phone call seeking an explanation.

In reality, concrete depths were much greater in many instances. For example, the main road leading into the recreation center was designed to be poured at a depth of 10 inches. Using the auditor’s four-inch assumption, it was calculated that 1,084 cubic yards of concrete was needed for the road. But in reality, the plans required the road to have 2,710 cubic yards of concrete. There were several other instances of similar differences in calculations.

The delivery tickets were meant to provide evidence that the amount of concrete delivered to the job site roughly equaled the amount of concrete called for in the plans. The city had inspectors on the job site verifying the amount and quality of concrete being installed at the site. But the review of batch tickets was designed to serve as an additional assurance that the amount of concrete installed was in line with what was called for in the designs. Concrete work at the sports complex accounts for the majority of the roughly $12 million worth of no-bid construction work that the city is paying for at the site.

In its written report to city commissioners, McDonald & Associates seemed to give the city assurances that concrete deliveries were in line with expectations. The report references a “Schedule I” in the development agreement for the project. The schedule, according to the report, “provides an estimate of the quantity of concrete required to fulfill the specifications.” City officials agree that is what the schedule provides. The quantities of concrete are listed in several different units of measurement such as square yards, linear feet and cubic yards. The delivery tickets, however, list all the concrete delivered to the site in cubic yards. To compare the delivery tickets to the schedule, the audit firm converted the numbers on the schedule into cubic yards.

In its report, the audit firm stated “Schedule 1 estimate was 7,276 cubic yards of concrete.” That figure is roughly equivalent to the 7,171 cubic yards of concrete that showed up in the incomplete batch of delivery tickets reviewed by the auditing firm. The report used those numbers to verify that the amount of concrete delivered generally met the expectations called for in the design.

But upon further review, it became clear that the 7,276 cubic yards of concrete did not represent the entire amount of concrete called for in the infrastructure plans. The city’s review found that 17,471 cubic yards of concrete was called for in the designs, and that 16,475 cubic yards of concrete was delivered to the site. City officials have said they’re comfortable with that level of variance.

Why such the large difference between the number listed in the audit report and the number determined by city officials? It appears the 7,276 cubic yards represents the auditor’s estimate that was based upon the calculation that all concrete was poured to a depth of four inches. The majority of the concrete was poured to depths ranging from 5 inches to 10 inches, which would account for the large discrepancy between the city’s number and the number presented in the audit report.

City officials asked the auditing firm to provide additional information about how it arrived at the deflated number. In a written response, Hudson said his number was meant to be a sample, not a complete accounting of all the concrete in the job. The report provided to city commissioners, however, never called it a sample. In his response, he did not explain why he chose to calculate all the totals using a 4-inch depth when documents clearly showed the majority of the concrete was poured to depths greater than 4 inches. The written response also did not explain why he used delivery tickets that city officials have now determined were not related to the infrastructure project. City officials also did not have an explanation for why those non-infrastructure tickets were included in the documents given to the auditor.

Amyx, who has been a consistent critic of the Rock Chalk Park process, said the way the numbers have been handled has left him with questions about the entire report.

“Is the entire audit compromised at this point?” Amyx said. “I’m going to wait until we go through all of this to make that determination. But I’m sure on Monday morning I’m going to do more visiting with our staff about this.”

Others said they still believed the main findings of the audit — which said the parties had followed the proper agreements and that the city was paying an appropriate amount for the work — were valid.

“I haven’t found any other examples or information that I’ve reviewed that makes me question the veracity of the rest of the report,” said Commissioner Mike Dever, a longtime proponent of the project. “I think the evaluation of the batch tickets, in many ways, are really inconsequential to the costs of the project.”