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 CO2 equivalent (kg CO2e) for every 1% of TDI improvement, or 9–14 kg CO2e 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.