Routes to restoring tidal flats - summary

The primary reason for re-creating tidal flats is to create habitat suitable for birds which use the flats to feed. Restoring eroding (State 2) to accreting (State 1) tidal flats is simple to describe but much more difficult to achieve.

Assuming that all the physical conditions affecting the site remain the same, successful restoration rests on increasing the availability of sediment. A key question for success in relation to bird usage is the speed and type of colonisation by invertebrates and plants, notably Zostera spp. Where there is abundant sediment either naturally or as a result of sediment recharge, then physical structures can be employed to increase the rate of sedimentation. The methods adopted to some extent depend on whether the aim is to move seaward, maintain the existing position of the flats (by raising the level of the surface) or to allow re-creation on former tidal land. Each of these may be used separately or in combination with other approaches designed to improve sea defences (through beach nourishment) and/or re-create saltmarshes by managed realignment.

In addition to re-creating the tidal flats the extent of recolonisation by invertebrates and Zostera can be enhanced. This will be largely designed to improve the usage by wintering and passage waterfowl. In deciding on what action to take there are a number of conclusions and caveats which are important to the restoration of this habitat.