Environmental Engineering Reference
In-Depth Information
• There is an abundance of geologic and hydrogeologic data
• It has a long history of industrial output
• It has significant environmental impacts
• It has similar geology to many other cities in the United States
The Rouge River watershed has over 200 km of streams, tributaries, lakes, and ponds, and
encompasses an area of approximately 1200 km 2 (460 mi 2 ) (Murray and Rogers 1999a). The
fan-shaped watershed includes all or part of 47 municipalities in three counties. Over 66%
of the watershed has been developed, and in the year 2000, 99% of the watershed's popula-
tion lived within the U.S. Census-defined urbanized areas—making it the watershed with
the highest population density in the eastern United States (Kaufman et al. 2003).
The near-surface geology of the watershed is dominated by glacial deposits, glacial
lacustrine deposits, and the recent fluvial deposits from the Rouge River itself. The glacial
deposits are generally greater than 61 m (200 ft) in thickness, the glacial lacustrine deposits
are rarely more than 9 m (30 ft) thick, and the recent fluvial deposits are generally less than
3 m (10 ft) thick (Farrand 1982, 1988; Rogers 1996, 1997c). Distinctive geologic units identi-
fied and mapped within the watershed include
• Four different surface moraine units that include the Fort Wayne Moraine, the
Outer and Inner Defiance Moraine, and the Birmingham Moraine
• Glacial outwash deposits
• Several beach deposits composed of sand from historical glacial lakes
• Silt and clay deposits from historical glacial lakes
• Recent fluvial deposits from the Rouge River
• A ground moraine or lodgment till composed of clay underlies the entire water-
shed beneath the near surface deposits described above
• A sand and gravel deposit located beneath the ground moraine in the center por-
tion of the watershed. This feature represents a fluvial deposit from a large river
that was present before the last glacial advance approximately 22,000 YBP
• Weathered bedrock encountered beneath the ground moraine at other locations
• Bedrock composed of shale, limestone, and sandstone of Paleozoic age present
beneath the unconsolidated units
The geologic map and stratigraphic column for the watershed are shown as Figures 5.20
and 5.21, respectively. The geologic map of the Rouge River watershed was produced using
the methods described in Chapters 4 and 5 and included information from more than 3000
subsurface environmental investigations conducted within or adjacent to the watershed.
Production of this geologic map also relied on the information gathered from numerous
sources of historical literature.
Anthropogenic effects within the Rouge River watershed have been numerous and
significant. Surface water and groundwater within the watershed have been severely
degraded. In recent assessments, the Rouge River was ranked as one of the most toxic sites
in Michigan (Michigan Department of Environmental Quality 2008). The watershed is also
the focus of ongoing intense scientific study and restoration. It has been identified as an
Area of Concern by the International Joint Commission (Hartig and Zarull 1991) and cited
as a significant source of contamination to the lower Great Lakes (Murray and Bona 1993).
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