RSPB Scotland is planning improvements for people and wildlife at the site on the south-eastern edge of Alloa.
The wetland and grassland is a popular site for birds including snipe, short-eared owls, teals and black-headed gulls.
New paths, viewing areas and signage are to be installed over the coming months with a series of events planned.
The wetlands near the banks of the Forth and the Black Devon river were created when soil was dug out to cap a nearby landfill area.
Managed lagoons were formed by Clackmannanshire Heritage Trust, and later expanded in the mid 2000s by the council's landfill project.
RSPB Scotland's regional director for south and west Scotland, Anne McCall, said: "We're delighted to be taking on the management of the Black Devon Wetlands and we hope to transform it into a reserve that will not only help wildlife, but also provide local people with a great nature experience right on their doorstep.
"The Inner Forth is internationally recognised as an important place for birds, and the establishment of this reserve adds to a wider mosaic of habitats that are beneficial for a whole range of different species, as part of the RSPB's landscape-scale project, the Inner Forth Futurescape."
Scotland's newest nature reserve is to be set up at the Black Devon Wetlands in Clackmannanshire.