Outline of the Park and Erosion

Presque Isle State Park is a 1295 ha migrating sand spit that juts 11.3 km into Lake Erie and is a major recreational landmark for approximately 4 million visitors each year. The park, a National Natural Designated Landmark, is particularly environmentally sensitive with its constantly evolving shoreline (Figure 4) and the presence of numer ous plants recognized as being of exceptional value. Presque Isle is rated as one of the top birding areas in the Northeast, as birds use the distal end of the spit for a resting and feeding area.

Figure 4 Presque Isle State Park. (a) Aerial view of Gull Point and the park from the east. (b) The shore on the bay side, looking north. (a) Photographer: Robert K. Grubbs, http:// en.wikipedia.org/wiki/Image:PresqueIsleStatePark.JPG; (b) http://en.wikipedia.org/wiki/Image:PresqueIsleBay-lookingN.JPG.

Figure 4 Presque Isle State Park. (a) Aerial view of Gull Point and the park from the east. (b) The shore on the bay side, looking north. (a) Photographer: Robert K. Grubbs, http:// en.wikipedia.org/wiki/Image:PresqueIsleStatePark.JPG; (b) http://en.wikipedia.org/wiki/Image:PresqueIsleBay-lookingN.JPG.

Protection of the spit has been an ongoing process since 1828. Along the Lake Erie shoreline, a series of conventional erosion control techniques such as groins, bulkheads, seawalls, and beach nourishment have been used with varying degrees of success. Between 1989 and 1992, many of the previous structures were removed and 55 offshore rubble mound breakwaters were constructed. Since completion of the breakwaters, shoreline mainte nance has been limited to an annual beach nourishment program. Construction of the breakwaters has decreased sand purchased for annual nourishment by c. 85%, from approximately 231 000 m3 before breakwater installation to c. 30 764 m3 after breakwater construction.

Since 1975, the beaches along the lakeside of the park have been nourished annually; nourishment amounts var ied based on fluctuating lake levels and storm severity. The prevailing winds along the lake are from the west, and, as a result, the beach sand is in continual motion as it moves in response to longshore transport. While most of this transient sand is redeposited in offshore bars in the lake, some of the sand is carried around the distal end of the spit into the back bay area. Accumulation of this fine grained material in the back bay has been a continual problem as these shallow areas become choked with sedi ment. As a result, the park struggles with the problem of dredging these areas and finding a suitable disposal option for the dredged material.

Historically, protection of the shoreline from erosion had been accomplished along the Presque Isle Bay side of the park by utilizing large stones to riprap the shoreline. Although this process was very effective in preventing shoreline erosion and was quite suitable in the more developed recreational areas of the park, because of its 'non natural' appearance, riprap did not concur with the desired results and appearance specified by the manage ment plan for the low density and natural areas.

As a result of the fragile ecosystem of the spit, specific erosion problems along the bay, and the development of a sand bar within the park's back bay area, the decision was made to seek funds to advance an innovative solution to these problems. With this goal in mind, the Department of Conservation and Natural Resources, Bureau of State Parks - Presque Isle State Park, in conjunction with the Presque Isle Partnership, secured funding via a matching grant from the Great Lakes Commission. The project coordinated efforts between state and federal government units, as well as private, nonprofit volunteer organizations to design, implement, and provide construction services for the project. This project brought forward a concept that provided the park with the protection needed for the infrastructure as well as creating a shoreline appearance that resembled natural shorelines along environmentally sensitive areas of the park. Additionally, the project pro vided a beneficial use of dredge material from the back bay sand bar.

In order to realize the goals of the project, the decision was made that rather than solely utilizing conventional riprap, the project would incorporate a combination of riprap as well as indigenous vegetation, bioengineering, dredge material, and innovative landscape architecture to retard shoreline erosion along a heavily used multipur pose trail. Completion of this project has provided valuable information to other parks and recreational facil ities in the Great Lakes area (especially along bay inlet areas), which are also faced with the challenges of mini mizing erosion and sedimentation as well as finding a beneficial use for dredge material.

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