For a few minutes Wednesday evening, Hays Aquatic Park’s lazy river ran yellow, as thousands of rubber ducks floated their way around the stream.

That’s because the ducks are back, as announced by many neon yellow signs placed throughout the city of Hays. Big Brothers Big Sisters of Ellis County will host its annual Duck Derby fundraiser beginning at 5:30 p.m. Wednesday at the pool. Residents make donations to “adopt” as many rubber duckies as they want, and the ducks -- each marked with an identifying number -- race down the waterslide and around the river.

Event organizers conducted a “test run” at the pool Wednesday, much to the delight of local children who were finishing an evening swim.

“That’s a lot of ducks,” one young bystander could be heard saying. “Holy macaroni.”

There will be four heats, each consisting of approximately 2,500 ducks. The winners of each heat will proceed to the grand championship race, and the owners of the first 10 ducks to cross the finish line will win a major prize.

The first-place prize is a Chevy Spark, which was a gift from several local car dealerships. Other prizes will include furniture, a Traeger grill, and tickets to sporting events.

The event also will feature a separate “duck dash” just for kids, featuring brightly colored ducks. That race will be similar to the main event, and prizes will be awarded to the top finishers.

Another highlight will be cardboard boat races. Participants must create a ridable watercraft using only cardboard and duct tape.

“It’s a ton of fun,” said Jenny Bates, area director of Kansas Big Brothers Big Sisters. “It was great to see how everyone constructed their boats, what they looked like. Many of them ended up coming in costume.”

The winners of last year’s race had the privilege of naming this year’s boat contest, hence the name “Hays ‘Merica Cardboard Regatta.”

The boating teams will race in the facility’s lap pool, and awards will be given to the top finishers, as well as a spirit, best of show and “Titanic” award.

The pool will have free admission from 5:30 to 8:30 p.m. Wednesday for the event for those who want to come enjoy the fun. There also will be a picnic available with a free-will donation.

All proceeds help support Big Brothers Big Sisters programming. The agency matches local children with positive role models, Bates said. There are 125 matches in Ellis County, and 35 children remain on a waiting list.

“Our longest match right now has been together for almost 12 years,” she said. “We get to see the kids grow up and change and see how it is impacting the kids’ lives, helping them build their self-esteem.”

Ducks still can be adopted at several local businesses or online at haysduckderby.net.