The long-term management of the 116 acre nature reserve has been protected after the council agreed to take over the ownership of the site.
Portbury Wharf Nature Reserve in Portishead was created by North Somerset Council as part of a section 106 planning agreement to provide a green buffer between the port and the Ashlands housing development.
The site is a popular recreational and wildlife area.
Cllr Steve Bridger, North Somerset Council's executive member with responsibility for assets said the adoption of the site was great news for the local community.
"This is a very popular public space that is also a haven for wildlife.
"The adoption of the site by the council will ensure that the nature reserve can be enjoyed for generations to come."
The council has had a longstanding legal agreement with developers Persimmon about the future ownership of the land to ensure the site remains protected from future development, with access available and wildlife able to flourish.
The site was previously managed by Avon Wildlife Trust (AWT) until the end of 2015 when North Somerset Council took over the management using their contractors, Glendale, to carry out maintenance tasks.
North Somerset Council has secured a contribution from Persimmon who will now transfer £75,000 to finance the future maintenance of the site until 2027.
North Somerset Council will approach local councils and other organisations to seek further contributions and investigate other sources of funding to support the site’s long-term conservation.