River Restoration Through the Lens of Carbon Sequestration

River restoration is currently applied to a wide variety of river management. Because natural channels are inherently mobile and dynamic, restoration is a misnomer for river management in which channel-form stasis is a primary goal. Although river scientists emphasize the importance of restoring physical and ecological processes and natural regimes of water and sediment, this conceptualization of river restoration may have limited appeal to stakeholders who are concerned about hazards associated with river movement or flooding, or who are accustomed to seeing simplified, homogeneous channels and floodplains. Stakeholder acceptance of more dynamic river corridors may be enhanced by clearly articulating the connections between river dynamics and either charismatic fauna such as salmon or beaver, or ecosystem services. Among ecosystem services, carbon sequestration is currently a concern of many stakeholders. Research within the past decade indicates that channels and floodplains can have much greater organic carbon stocks per unit area than adjacent uplands. Organic carbon can be stored in river corridors in the form of soil organic carbon (typically the largest reservoir), downed, dead wood, and living floodplain vegetation. River restoration that seeks to hydrologically and geomorphically connect channels and floodplains; promote high floodplain water tables and associated reducing conditions in floodplain soils; natural floodplain vegetation communities; and retention of downed wood all have the potential to substantially enhance organic carbon stock in river corridors. Implementing river restoration designed to enhanced carbon sequestration is likely to be most effective when based on an understanding of the natural water, sediment, and large wood regimes, the degree to which these regimes can be restored, and the likely response curves for variables such as downed wood or soil organic carbon at the restoration site.