Lower water level to restore degraded brackish/salt marshes
Overall effectiveness category No evidence found (no assessment)
Number of studies: 0
Background information and definitions
This action involves one-off action to lower the water level in degraded marshes, to a depth that should support emergent vegetation. This means that intervention should (a) occur at one point in time, after which the water level is not actively managed, and (b) must affect a marsh that is wetter than normal, but is still recognisable as, or retains substantial characteristics of, the target habitat. Specific techniques to reduce water levels include removing dams downstream, switching off pumps that add water to a focal site, and improving drainage by digging shallow “runnels” or deeper creeks (Wigand et al. 2017).
Caution: This action may have negative effects on habitats elsewhere in the catchment. For example, removing dams could flood marshes, swamps or upland habitats downstream. There may also be conflicts with water needs of human populations that need to be managed.
Related actions: Lower water level to restore/create marshes from other land uses; Backfill canals or trenches; Actively manage water level; Manage water level to control problematic plants; Reprofile/relandscape, may involve raising the ground surface towards or above the water table; Lower water level to complement planting.
Wigand C., Ardito T., Chaffee C., Ferguson W., Paton S., Raposa K., Vandemoer C. & Watson E. (2017) A climate change adaptation strategy for management of coastal marsh systems. Estuaries and Coasts, 40, 682–693.