Operation and Maintenance
A managed realignment project does not end when the construction is finished. After construction the management and maintenance phase starts. Different strategies can be applied. One of the main post-construction strategies of a managed realignment is Adaptive management and monitoring.
Adaptive management and monitoring
Adaptive management and monitoring will be necessary after realisation, to address uncertainties and achieve project success. Although the design features should direct the restoration to meet its ecological objectives, a number of uncertainties and data gaps exist that can only be resolved by implementing management actions and learning from the results to improve future management actions. This process of learning by doing is called adaptive management. Adaptive management is iterative, evaluating actions through carefully designed monitoring and subsequently proposing adjustments. The adjustments are, in turn, tested with appropriate, and perhaps redesigned monitoring.
Moderate levels of uncertainty are associated with creating tidal wetlands and they warrant adaptive management with ‘implementation’ monitoring. Implementation monitoring is designed to evaluate the effectiveness of adaptive management actions and to steer the restoration towards its ecological objectives. This type of monitoring provides data on whether a given management action to improve the quality of tidal wetland habitat has been successful using a reasonable, previously tested action (presumably the best available technology developed by other projects). The data generated can be compared to a baseline condition or reference area to determine if the management action provided the predicted change in resource quality. Data from the implementation monitoring would be used to confirm that restoration actions are producing the desired trajectory to meet the success criteria for the developing habitat.
The critical determinants for adaptive management of tidal wetlands are:
- Rate of accretion indicates trajectory toward vegetated marsh
- Tidal wetland habitat establishment
- Impacts on intertidal habitats
- Endangered species use
- Bird use
- Fish use
- Water quality.
The critical determinants for adaptive management of seasonal wetlands are:
- Seasonal wetland habitat establishment
- Bird use
- Water quality.
Also Friess et al (2008) address the importance of monitoring during the post construction phase of a managed realignment:
To achieve maximum benefit from realignment schemes, the continued monitoring of site conditions before, during, and after implementation is critical. Monitoring results from several managed realignment schemes in the UK suggest that thresholds exist within the evolution of these ecosystems that alter their resilience and vulnerability to future hydrodynamic, sedimentological, and climatic changes. Such thresholds still need to be adequately quantified. To achieve this, continued monitoring is necessary and adds to the cost of scheme implementation.