Evaluation of potential use of vegetation for erosion abatement along the Great Lakes shoreline

Abstract

Erosional problems and damages include loss of land, imperilment to roadways, loss of recreational beach, loss of access to the lakes and structural damage to dwellings, boathouses, docks, and stairways: Some shoreline conditions along the Great Lakes are difficult to alter to control erosion, particularly in areas where there is no beach or where the water interfaces immediately with steep bluffs. However, there are numerous areas where erosion can be abated by attenuating wave action with mechanical barriers and then using terrestrial and aquatic vegetation to protect the shore against the reduced wave action and against surface runoff. There are three types of terrestrial plants that can be used to abate erosion: (a) pioneer plants, the species to first become established on new. substrates; (b) secondary plants, the species to first invade edaphically stable areas colonized by the pioneer plants; and (c) tertiary plants, the species poorly adapted to dynamic conditions and requiring areas previously stabilized by pioneer and secondary species. Most species used in terrestrial planting operations are the pioneer type. The pioneer initiates a development sequence (Cowles, 1899; Hack, 1941). It stabilizes the surface, provides lodging for windborne disseminules, shields seedlings from sun and wind, and prepares the way for natural invasion of other plant types (Daubenmire, 1968). Establishment of hydrophytes (submergent or emergent plants) is very difficult. They are highly restricted by currents and water level fluctuations. Emergent hydrophytes are limited to low-energy shores, w~ere.they modify less forceful waves; submergent aquatic plants establish ln even more protected areas. The restriction of submergent species to quiet waters limits their phytogeographical distribution, and their vulnerability to strong wave forces prohibits them from naturally colonizing the wave-swept littoral zones of lakes. The main purpose of this investigation was to determine if terrestrial and hydrophytic plants, either alone or in combination with structures, can be used to attenuate wave energy immediately offshore and to stabilize the areas adjacent to the waterline, thereby reducing the erosion rate along the Great Lakes shores.