Planted marshes are generally considered to be one of the most cost-effective and environmentally desirable erosion-control approaches. Fringing marshes protect adjacent uplands by gradually dissipating wave energy, absorbing the force of breaking waves, and stabilizing the soft, underlying soil. Planting marsh grass—which you can do yourself—has been particularly effective where previous marshes were destroyed by dredging and filling. Marshes can be created or restored by increasing tidal flow.

Marsh planting is most effective in areas that are sheltered from the wind and where waves and boat wakes are not a major problem. A marsh fringe at least 10 feet wide is necessary for erosion control, but 20 feet or more is preferred. If the marsh is not established continuously along the shoreline, erosion can continue on the unprotected areas. In some cases, two or more planting attempts may be required for the marsh to take hold. From a regulatory standpoint, marsh creation or restoration will likely require permitting on several levels (local, state, and federal). From the state standpoint, permits from Maine DEP will be required.

North Carolina's Shoreline Erosion Control Using Marsh Vegetation and Low-Cost Structures provides a good outline for how to plant and create a new coastal wetland. Similarly, the North Carolina Coastal Federation Erosion Control: Non-Structural Alternatives, A Shorefront Property Owner’s Guide provides some good guidance for marsh plantings. The techniques and species discussed in these guides are applicable to Maine’s marsh systems. Tidal bank protection using vegetative plantings is also outlined by the Maine DEP under their Maine Erosion and Sediment Control Best Management Practices (scroll down to Site Specific Applications of BMPs, Sand Dune and Tidal Bank Protection).

Commonly used grasses include species native to Maine salt marshes, such as saltmeadow hay (Spartina patens) and smooth cordgrass (Spartina alterniflora). Planting elevations can vary but can be determined by observing the elevations of healthy native marshes nearby. Marsh grasses may be purchased from specialized commercial nurseries (or can be potentially transplanted from existing marshes with a permit).

Phragmites australis, also known as common reed, is considered an invasive plant by the State of Maine and should not be planted or allowed to spread.

Increasing tidal flow into marsh areas by removing or replacing inadequately functioning road culverts can help facilitate the natural proliferation of marsh plants. Adequate tidal flushing is required for marsh growth, and also helps eliminate invasive species that are not salt-tolerant. Note that permits are likely required from Maine DEP and the US Army Corps of Engineers for work associated with road culverts.

Much of the above marsh restoration information was adapted from Managing Erosion on Estuarine Shorelines, which was prepared for estuarine shorelines in North Carolina. However, much of the information and techniques outlined transfer to Maine’s marshes. Additional online resources regarding techniques that provide good guidance for marsh restoration and creation include Maine Salt Marshes: Their Function, Values, and Restoration and Salt Marshes in the Gulf of Maine, Human Impacts, Habitat Restoration and Long-Term Change Analysis.