To establish existing conditions for dredge material beneficial use projects and to help implement principles of Regional Sediment Management (RSM) into projects and studies, this paper is an assessment of sediment sources and sinks, physical processes, and longshore sediment transport along the west and south shore of Lake Erie. This summary compiles information from a widely scattered technical literature and synthesizes the results in preparation for development of a sediment budget.
The U.S. shore of Lake Erie has 28 river or harbor mouths protected with jetties and structures, of which 16 are Federal navigation projects. Much of the sediment management since the mid-1800s has revolved around providing safe navigation, maintaining depth in navigation channels, and disposing of the dredged material.
Sediment sources include material brought down the rivers (often fine-grained); industrial dumping and runoff from sewers, gravel, sand, and clay eroded from glacial till bluffs and clay banks; sediment created in situ from bedrock bluff weathering (primarily from shale); and limited supply from lake bed lowering and offshore outcrops. Losses include wave- and ice-induced transport to deep water, sediment trapped in fillets at harbor jetties, sediment dredged from harbor entrance channel and placed in confined disposal facilities (CDFs) or placed offshore, bluff armoring, and (formerly) beach mining.
Today, the south shore of Lake Erie is severely sand-starved compared with conditions that existed 200 years ago. The lack of available sediment is largely due to man-made causes. As the shore developed and became urbanized after the mid-1800s, residents, industries, and municipalities attempted to arrest bluff erosion with the use of structures and vegetation. Now the U.S. shoreline of Lake Erie is almost 83% protected, a larger percentage than any ocean coast except in urban areas. It means that little sediment exchange occurs compared with predeveloped conditions, which, in turn, means that managers must recycle and reuse existing sediment to maintain recreation beaches. Managing sediment to benefit a region sustainably potentially will save money, allow use of natural processes to solve engineering problems, and improve recreation resources and natural habitat.
Cet article est une évaluation des sources et puits de sédiments, des phénomènes physiques et du transport de sédiment le long des côtes ouest et sud du lac Érié. L'objectif est de décrire les conditions environnantes actuelles pour les projets de mise en valeur des matériaux de dragage et ainsi faciliter l'implémentation des principes de Gestion Régional des Sédiments (RSM) lors de projets et études.
Information et données provenant d'une multitude d'articles scientifiques et de littératures techniques sont synthétisées et présentées en vue de la préparation d'un budget sédimentaire.
La berge américaine du lac Érié possède 28 embouchures de rivières et ports protégés par des brise-lames ou autre structures. Seize d'entre eux sont des projets de navigation sous le gouvernement fédéral.
Depuis la deuxième moitié du 19e siècle, la gestion des sédiments marin a surtout constitué à rendre les voies navigables sécuritaires, à maintenir la profondeur des canaux de navigation et à disposer des matériaux de dragage.
Les sédiments côtier proviennent de plusieurs sources, notamment des rivières (particules fines surtout), de rejet industriel (cendre et débris), des drains fluviaux, de l'érosion des escarpements de till (gravier, sable, argile) et des bancs d'argile, de l'altération des affleurements rocheux (surtout du shale), et finalement, en moindre importance, de l'érosion des sédiments et des affleurements rocheux situé au fond du lac. Les pertes de sédiments surviennent lors de leur transport en eaux profond
