Coastal Changes, Eastern Lake Michigan, 1970-73.
Abstract
This study concerns erosion of the bluff or edge of the terrace marking the landward boundary of the beach at 17 sites along a 250-mile segment of the east coast of Lake Michigan. Data were collected every 4 weeks for 3 years beginning in August 1970, during a period when monthly lake levels in Lake Michigan rose about 1.5 feet to record levels in the spring and summer 1973. Bluff or terrace erosion was intermittent during the first 2 years, but universal during the final year, suggesting a critical lake level of about 580.0 feet, International Great Lakes datum, above which erosion on this coast generally occurs everywhere. For the 3-year period, net bluff erosion varied from 1 cu yd/ft of beach front at two sites to a maximum loss of 39 cu yd/ft at the site on Big Sable Point. Erosion within the study area was intermittent over time periods equal to the survey interval (4 weeks), and local compared to distances between sites (about 15 miles). An aerial photo study of these sites from 1938 to 1972 showed that long-term erosion is closely tied to lake level, and that sand terraces form rapidly in the backshore during periods of low water. Beach sediments appear to be locally derived and sand size does not show a clear relationship to the slope of the beach face.
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 01, 1976
- Accession Number
- ADA033297
Entities
People
- Richard A. Davis Jr.
Organizations
- Western Michigan University