The hidden section of the River Penk ran beneath Penk Rise Park in Tettenhall Wood, Wolverhampton, after it was piped and buried during the development of a housing estate.
Residents had called for it to be restored to its former glory as part of the Tettenhall Neighbourhood Plan.
And now their wishes have been granted thanks to two-week project funded by The Wildlife Trust for Birmingham and the Black Country, who carried out the work in conjunction with the Environment Agency.
William Grove, who sits on the nature improvement board for the Environment Agency, said: "After it was found, Tettenhall said they wanted to uncover the river.
"The Wildlife Trust got involved but they didn't have the manpower for the project. We did."
"It was in a pipe where no one could enjoy it, and now we've created 100 metres of new habitat for the area.
"It's going to look good for the area too."
The final stage of the project saw grass seed scattered along the banks of the new stretch to repair turf which was damaged during the repair work.
Simon Atkinson, spokesman for the Wildlife Trust for Birmingham and the Black Country, said: "There is some important wildlife in the area that will benefit from the new river, and the park will benefit too. "The ground in the park won't be so damp anymore where the river used to enter and exit the pipes."
Mr Atkinson also revealed the partnership are planning to unearth another section of the river in a second project which is likely to cost £70,000, although the required funding has yet to be secured.
Permission for the work to be carried out on the land was given by Wolverhampton City Council.
Richard Welch, the authority's head of community recreation, said: "This is an exciting project which will enhance the open space, improve biodiversity and open up the river for residents.