The fourth annual Recycled Cardboard Boat Regatta — presented by the Delaware Nature Society’s Abbott’s Mill Nature Center — will cast off on Aug. 5 at the Nanticoke River Public Marine Park, 26 N. Market St., Blades.

Sign-in and registration will begin at 11 a.m., with judging of boats’ appearances at noon, and races starting at 12:30 p.m.

The regatta is open to anyone who can build a boat from recycled cardboard and paddle it about 200 yards to the regatta finish line. First-place awards will be given for winners of races in five different categories: individual, youth, teens, family and organizations or businesses. Special awards will be given for Pride of the Fleet, Most Whimsical Boat and Team Spirit. Also, spectators will be asked to pick a People’s Choice award winner, while a Titanic Award will be given for the Most Dramatic Sinking.

Boats may be any size, shape or design, but must be made of recycled cardboard. Boats should be painted with multiple coats of any one-part polyurethane or enamel paint. Boat decorations may be removed after judging, and prior to the race start.

Registration fee is $30, and participants can also register the day of the event. Participants also are encouraged to challenge others to race in the Recycled Cardboard Boat Regatta for one-on-one bragging rights and can do so by choosing the challenge option during registration. After all boat races are completed, skippers of cardboard boats may challenge another skipper and their boat to a race. There is a $15 fee for a challenge race, to be paid by both challengers. Challenges should be issued only to cardboard boats that are entered in the same regatta categories.

During the event, attendees can enjoy music, food, snacks and beverages and become better informed by the Reclaim Our River partnership on how to protect Delaware’s waterways. The ROR-Nanticoke Series is devoted to bringing monthly events, workshops and recreational activities to the Nanticoke Watershed. The series offers participants fun opportunities to connect with Delaware’s waterways and provides important information on water quality that can help in protecting aquatic resources.

The ROR partnership also welcomes event sponsors with proceeds going toward event costs, river restoration and water quality education. Sponsorships begin at $50.

For information or to register, visit delawarewatersheds.org or contact 422-0847 or alice@delawarenaturesociety.org.