Environment and conservation experts will be on hand throughout the event offering games, competitions, crafts, wildlife spotting and more.
Visitors will also be able to uncover the variety of wildlife found in the Witham, make wildflower seed bombs to use at home and take part in the popular pooh stick race to see how the flow of the Witham has been improved.
All of the activities have been designed to show how easy and fun it is to get closer to nature and play a part in protecting it.
Funded using fishing licence money from the Environment Agency, which is re-invested into rivers, helping to improve facilities for anglers, tackle illegal fishing and encourage more people to take up the sport, enhancements to the park include an area of stepped decking enabling safe access to a shallow part of the river and new wetland habitat to attract rare species.
Geomorphology technical specialist at the Environment Agency, Matt Parr, said: “Few things beat the great outdoors but that doesn’t mean you have to escape into the wilderness. Natural wonders can be found right in the heart of your town.
“We will be on hand to help spot the opportunities, using the beauty of Wyndham Park and our improvements to the river there, to show how easy and fun it is to get closer to nature.”
Organisations taking part in the event include the Environment Agency, South Kesteven District Council, Lincolnshire Rivers Trust, Anglian Water and Rivercare.
The event starts at noon on Sunday and runs until 4.30pm, to coincide with World Rivers Day.