Environmental infrastructure and practices designed to restore and protect aquatic systems are now mainstream. Yet many of these projects are failing to produce biophysical outcomes that they are designed for because of poor maintenance. The success of restoration projects is just as much a consequence of how they are maintained, as it is how the project was initially designed and implemented.
Successful maintenance relies on understanding the ecological and biological trajectories of aquatic systems. Some interventions will require ongoing maintenance indefinitely, whereas others will reach a self-sustaining point where maintenance is no longer required. Different management arrangements are required to ensure the maintenance of different types of project. Those projects that involve high costs should be managed using more robust arrangements, such as legal regulation, compared to those projects that involve lower costs.
Some river restoration interventions can become self-sustaining relatively quickly, whereas others might require some level of maintenance for decades to eventually reach a self-sustaining state. For example, gully control structures combined with revegetation can become self-sustaining within a decade.However, sediment extraction for the management of sand slugs can require decades to achieve outcomes.
Ongoing interventions involve infrastructure and practices that must be maintained in perpetuity to achieve environmental outcomes. Examples include fishways for instream restoration, riverbank fencing for stock exclusion, the infrastructure and practices required to deliver environmental flows, and and actively excluding cattle from the river frontage. In all cases, if the intervention ceases, the trajectory of recovery can reverse and degradation will reoccur.
In practice, almost all interventions will require some form of future management, however minimal.
In their paper Lack of maintenance is a major challenge for stream restoration projects, Harriet Moore and Ian Rutherfurd describe the maintenance required for common river restoration projects and outline a classification of projects based on maintenance and recovery trajectories. They consider the types of management arrangements required to ensure maintenance, and the costs of this maintenance. Finally, these points are illustrated with three case studies of typical restoration actions (riparian stock exclusion, fish passage and restoring large wood loads).
Key conclusions from this paper include:
- River restoration interventions fail when they are not maintained.
- Some interventions are self‐sustaining whereas others require ongoing maintenance, and, importantly, the trajectory of this recovery can be predicted, and planned for.
- How well projects are maintained depends on management arrangements. Decisions about management should be informed by the recovery trajectory of degraded environmental assets, and whether interventions address symptoms or causes of degradation.
- Interventions that are more costly, and require more maintenance, particularly those that require eventual replacement, need more reliable management instruments. Ongoing interventions pose the greatest challenge for river restoration because they need ongoing funding and permanent arrangements for management.
- Voluntary instruments are only appropriate when implemented effectively.
- All management arrangements require oversight from an independent authority to ensure maintenance occurs.
Establishing new river restoration projects has been a central focus of the past two decades. The problem of maintenance has emerged as projects mature. Interventions should be implemented through instruments that ensure they will be maintained long enough to allow the degraded environmental asset to follow the expected recovery trajectory through to an improved condition.
This article was adapted from Lack of maintenance is a major challenge for stream restoration projects by Harriet Elizabeth Moore and Ian D. Rutherfurd. The full paper is available here.
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