Quantifying carbon footprint for ecological river restoration

RIVER restoration is a popular technique to rehabilitate degraded river habitat. Given the nature of these types of engineering projects, using ecological indicators to monitor the restoration effectiveness has been a traditional approach. However, as this approach emphasizes the post-project performance, environmental impact attributed to a project’s construction phase has received little attention directly or indirectly. This study quantified the carbon footprint of ecological river restoration, using a project in California as a case study. A topographic diversity index (TDI) was developed as a functional unit of the river restoration project, indicating how a restoration project can increase the variation of habitat topography. The results show that river restoration can lead to greenhouse gas emissions ranging from 288 to 336 kg CO 2 equivalent (kg CO 2 e) for every 1% of TDI improvement, or 9–14 kg CO 2 e per meter stream restored. This study identified that improving raw material acquisition plans and heavy-duty equipment rental decision can be feasible strategies leading to the reduction of carbon footprint.