In cities, before having proper sewage system, rivers were used as open sewers. With the urban population growth, they were filthy and a real disease vector, so the local authorities decided to burry them in culverts. Now these hygiene issues are ended in most modern cities, some localities think over these systems. Indeed, a PhD Thesis of 2011 demonstrate that culverts can locally lead to considerable habitat fragmentation in rivers and streams bescause of the abrupt changes in light conditions and streams bed substrate. Therefore deculverting rivers would be benefical for the reduction of flood risk, for the ecological regeneration of these habitats and it would create great opportunities to build areas of nature in the heart of cities.

The city council of Sheffield in UK decided to bring back to life  one of these river, the Porter Brook, in 2015. Since 1853, it was buried in a pipe then enclosed by a brick tunnel under a car park. A lot of people had to come to work together in order to create a valuable habitat and enable species to colonize it : the local university technical college, a landscape architect, environmental agencies…