Entrance to at BREC's Baton Rouge Zoo, seen looking down the driveway from Thomas Road, Thursday, Aug. 17, 2017.

Baton Rouge’s park officials expect to prevent future floods at their hoped-for Baton Rouge Zoo site on Airline Highway by turning the lowest-elevation patches into a series of ponds and undeveloped greenspace that they believe will make the property able to handle intense storms.

BREC and zoo leaders have zeroed in on the Airline Highway Park and state fairgrounds as the site that they hope to use for a new Baton Rouge Zoo. They will ask their board of commissioners on March 22 to agree to relocate the zoo to the Airline site. Board members voted last year to authorize BREC officials to look for a new site for the zoo.

The Airline Highway Park had once been taken off the table as a home for the zoo because the property flooded in August 2016. Parts of the site are beneath FEMA’s base flood elevation for a 100-year flood, which predicts how high water would rise in a flood that has a 1 percent chance of occurring annually. And city-parish modeling from the flood shows that parts of the park nearest to Bayou Manchac and Ward’s Creek received more than 10 feet of floodwaters.

The current zoo off Highway 19 in north Baton Rouge, however, did not flood.

One of the engineers BREC hired to determine whether the Airline site was feasible for the zoo shared his firm’s development plans Wednesday. Though the park is more than 130 acres, Michael Thomassie, a senior associate with Duplantis Design Group, said that they would use the 75 acres closest to Airline Highway for zoo exhibits. The remainder of the park would be dedicated to flood mitigation, mostly in the form of ponds and “undisturbed areas,” which include wetlands.

“Once we saw how much high ground we truly had, we thought it was worth exploring further,” Thomassie said, noting that more than 39 acres of the park are higher than FEMA’s base flood elevation.

Engineers want to expand the size of the area above the base flood elevation by moving dirt from the lowest parts of the site to the parts that BREC would use for the zoo. Then the low-elevation spots would mostly become detention ponds.

BREC Assistant Superintendent Reed Richard said they would make the ponds and other amenities to catch stormwater look as natural as possible to blend in with the zoo.

The combination of cutting into the lower parts of the park and filling the higher parts of the site should result in a 10 percent increase in floodplain storage for a 100 year storm, according to the engineers.

The site currently has 598,972 cubic yards of floodplain storage and they want to increase the number to 668,375 cubic yards, according to the engineering firm.

“When the same flood comes, it won’t be stored in an inconvenient area of the site,” Thomassie said, referencing the flood in August 2016.

The detention ponds would also be key for the Airline site’s drainage. BREC expects that they can decrease stormwater discharge from the Airline site by 10 percent for 10-year and 25-year storms. Thomassie said they will study more intense storms as well.

Hydrologist Bob Jacobsen, who has deeply studied the 2016 flood, has tried to rally engineers and flood risk managers to start planning more for 500-year and 1,000-year floods.

"The 100-year flood is not an extremely rare event — there’s better than a 50-50 chance of such a flood occurring at a location over a typical lifetime," Jacobsen said, emphasizing that he was not taking a stance on the zoo's relocation or the merits of the Airline site.

"In flood risk management, our profession is increasingly evaluating impacts for 500- and 1,000-year events," he said. "This is especially true given the amount of uncertainty with estimating a 100-year flood level, the fact that current FEMA estimates in many areas are woefully outdated, and that climate change and other factors are changing estimates of flood risk. What we think of today as a 500-year flood may become tomorrow’s 100-year flood."

Asked whether the cutting and filling required at the Airline site would increase the price tag for a new zoo, currently estimated at $110 million, BREC Superintendent Carolyn McKnight said it should not drive up the cost substantially. A cost breakdown prepared in 2016 for rebuilding the zoo budgeted $800,000 for “major earthwork” if the zoo was relocated to the Airline park.

BREC Chief of Management and Business Service Corey Wilson estimated Wednesday that the cut and fill work would cost between $1 million and $2 million. He and Richard said it’s cheaper for BREC to move dirt from one part of the site to another, rather than to bring it in from the outside.

“It’s a lot of dirt to move around, but you can move it around pretty cheaply,” Thomassie said.

When BREC and zoo leaders first started to look for land for the new zoo, they said they wanted sites that were around 100 acres. McKnight said Wednesday that was meant to ensure the site would have enough space for parking, flood mitigation and other factors. The current zoo only occupies 70 acres on its 125-acre site, and McKnight said the developable parts of the Airline site are plenty large enough to fit the relocated zoo.

She said the site has fit the criteria BREC is looking for better than any of the other 19 locations they have considered. BREC owns the land and would not have to pay for it. And the site is near Interstate-10 in a highly trafficked area, which they believe would lure more visitors. 

“This is the ideal location,” McKnight said.

Day4FloodingAerials bf 0174.jpg

The State Fair Grounds. Aerials of severe weather flooding in East Baton Rouge Parish on Monday August 15, 2016.

While McKnight tries to build support for the Airline Highway site leading up to the March 22 meeting, opponents to moving the zoo are also making plans. The Keep the Zoo at Greenwood Park group, which has repeatedly criticized the plans to move the zoo, has planned four rallies over the next three weeks to “energize and inform residents throughout East Baton Rouge on the adverse economic impact that a zoo move would create, data showing the current location is the most sustainable.” The first meeting is at 6 p.m. Thursday at the Zachary branch library. 

Critics, including Metro Councilwoman Chauna Banks, have seized on the contracts BREC executed with Duplantis and with a traffic consultant for the Airline site, questioning why McKnight was not forthcoming about them to the public.

BREC’s initial contract with Duplantis was for $10,000, and BREC extended the contract last month for an additional $17,300 for the company to do more work on the site. BREC is still awaiting the results of its traffic impact study. They hired Vectura Consulting last month for $14,875 to perform that review.

McKnight said BREC does not plan to host any public meetings about the drainage and flood mitigation plans for the Airline site until they receive commission approval. BREC is, however, meeting with homeowners associations near the park.

While BREC has sketched out its potential plans to fund the zoo rebuilding campaign, McKnight and Wilson said Wednesday that it is still too early in the process to know for sure how to pay for it. They said donors were turned off the by the idea of investing in the current zoo site, but that they were open when BREC first approached them years ago to the idea of a zoo in a different location.

“If we can’t do it for Airline then we certainly can’t do it for Highway 19,” Wilson said about fundraising.

They still hope to privately fundraise and explore corporate sponsorships for the zoo. And they have also have come up with ideas for a potential tax package, which would include the zoo as well as a renovated Greenwood Park at the current location, walking trails throughout the parish, improvements to the City Park lakes and more.

Follow Andrea Gallo on Twitter, @aegallo.​