Modern urbanisation makes use of increasingly decentralised management approaches and natural drainage features, reducing the impacts of new urbanisation. However, legacy issues exist in urban areas, with few examples of significant recovery of urban streams from restoration efforts.
Stream burial is the most severe form of stream modification because most interactions with the surrounding environment are removed. Stream daylighting is a radical form of restoration that recreates open channel from a buried channel. Daylighting is promoted as a restoration tool and can theoretically restore stream structure and natural processes, but effectiveness assessments are lacking.
The daylighting of two stream reaches in Auckland, New Zealand’s largest city, in 2013 allowed the assessment the effects of daylighting using a paired assessment approach, where one reach had a large area of intact native forest in the headwaters. The macroinvertebrate community changed significantly with the improved habitat; the reach with native forest in its headwaters showed a greater change. The differential response indicates the outcomes of daylighting projects are context specific, hence it’s use should be tailored to the local setting, rather than used as a ‘one size fits all’ restoration tool.