River restoration project showing levee removal and riparian vegetation.

River Restoration: Can Removing Levees Bring Back Natural River Dynamics?

Soraya Malik in Climate & Environment August 2025 • 4 min read.

"A new study investigates the effectiveness of dismantling artificial barriers to revitalize rivers and floodplains, promoting biodiversity and natural resilience."

Rivers shaped by human activities often struggle to support diverse plant life. In many altered landscapes, natural river migration is restricted to narrow zones by levees and revetments, limiting the regeneration of vital riparian ecosystems. However, a strategy involving the removal or modification of these longitudinal structures is being explored to revitalize riverscapes and encourage natural processes.

Longitudinal structures manipulation, which involves removing or setting back artificial levees and channel revetments, seeks to reactivate channel migration. This, in turn, aids in restoring flood-dependent riparian plant communities in constrained floodplains. These areas depend on the dynamic movement of rivers to create the moist, open habitats required for pioneer species to thrive.

A recent study has assessed the impact of such interventions on a 21.6 km stretch of the Órbigo River in NW Spain. The project, completed in 2012, involved comparing restored segments with control segments to evaluate changes in land cover, channel formation, and vegetation. This evaluation provides critical insights into the effectiveness and challenges of large-scale river restoration efforts.

How Effective Is Levee Removal in River Restoration?

River restoration project showing levee removal and riparian vegetation.

The Órbigo River project offers valuable insights into the potential of dismantling artificial structures to restore river ecosystems. The study focused on a 21.6 km restored segment, comparing it with a downstream non-restored (control) segment and an upstream unregulated (reference) segment. Data on land cover changes and channel planform evolution were collected before (2011) and shortly after (2014) the restoration, with riparian vegetation surveyed in 2016.

Key findings indicated that the restored segment experienced the most significant increase in active channel area. This rejuvenation of landforms was more pronounced in the restored and reference segments compared to the control segment, where succession toward mature stages predominated.

Increased active channel area: The restored segment showed the largest expansion.
Landform rejuvenation: Dominated in restored and reference segments.
Increased complexity: Sinuosity and braiding indexes rose significantly in the restored segment.

While the initial results are encouraging, the study also reveals the limitations of such interventions. The high stability of floodplains in human-constrained rivers can limit the short-term effectiveness of longitudinal structures manipulation. The variability within the restored segment highlights the dependence of riparian plant communities on local processes, underscoring the complexity of river restoration.

Looking Ahead: Adaptive Management and Long-Term Monitoring

The Órbigo River study highlights the necessity of continuous monitoring and adaptive management strategies in river restoration. Long-term monitoring of geomorphic trajectories and plant communities is essential to determine the timing of future interventions, ensuring the natural resilience of riparian habitats. Further research should focus on integrative approaches that combine ecological and technical actions with socio-economic, educational, political, and legal considerations to maximize restoration success.

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This article is based on research published under:

DOI-LINK: 10.1016/j.ecoleng.2017.08.005, Alternate LINK

Title: Dismantling Artificial Levees And Channel Revetments Promotes Channel Widening And Regeneration Of Riparian Vegetation Over Long River Segments

Subject: Management, Monitoring, Policy and Law

Journal: Ecological Engineering

Publisher: Elsevier BV

Authors: Vanesa Martínez-Fernández, Eduardo González, Juan Carlos López-Almansa, Sofía Maura González, Diego García De Jalón

Published: 2017-11-01

Everything You Need To Know

What is the primary goal of manipulating longitudinal structures like levees and revetments in river restoration projects?

Longitudinal structures manipulation, such as removing artificial levees and channel revetments, is employed to reactivate channel migration. By allowing the river to move more freely, it promotes the restoration of flood-dependent riparian plant communities in constrained floodplains. These communities rely on dynamic river movement to create moist, open habitats crucial for pioneer species. However, the effectiveness can be limited by the stability of floodplains in human-constrained rivers.

What were the key findings of the Órbigo River project regarding the effectiveness of dismantling artificial structures in river ecosystems?

The Órbigo River project compared restored segments with control and reference segments. It was observed that the restored segment experienced the most significant increase in active channel area, coupled with landform rejuvenation. Key indicators included increases in sinuosity and braiding indexes, reflecting enhanced channel complexity. These results are tempered by the fact that plant communities show variability, demonstrating dependence on local conditions.

What are some limitations of using longitudinal structures manipulation in river restoration, especially concerning floodplain stability?

The success of longitudinal structures manipulation is often limited by the inherent stability of floodplains in human-constrained rivers. This stability can hinder the short-term effectiveness of interventions. Additionally, the variability in riparian plant communities within restored segments underscores the dependence on local processes, highlighting the intricate nature of river restoration efforts. Consideration of these factors is important in river restoration projects.

Why is continuous monitoring and adaptive management considered essential in river restoration projects, particularly after interventions like levee removal?

Long-term monitoring of geomorphic trajectories and plant communities is crucial for adaptive management in river restoration. This continuous assessment helps determine the timing of future interventions, ensuring the natural resilience of riparian habitats. By tracking changes over time, managers can adjust strategies to optimize restoration outcomes and address unforeseen challenges, particularly with the effects of Longitudinal structures manipulation.

What broader approaches should future river restoration research emphasize to maximize restoration success, beyond just ecological and technical actions?

Future river restoration research should focus on integrative approaches that combine ecological and technical actions with socio-economic, educational, political, and legal considerations. This holistic perspective ensures that restoration efforts are not only ecologically sound but also socially and economically sustainable. For example, while Longitudinal structures manipulation may have an ecological impact, without social and economic support, the long-term success of the effort can be limited.