& Great Lakes
|The Fox River -Green Bay region of the Great Lakes has been
known for decades as one of the most polluted bodies of water in North
Largest tributary to Green Bay
Flows north from the outlet of Lake Winnebago.
Length --- 39 miles (64 km)
Contributes most of the pollution to Green Bay.
Highest concentration of pulp and paper mills in the world. (24 mills
on 39 miles of river.)
Drainage basin --- roughly 6,250 square miles of land surface.
(about 16,000 square km) Most of the area (about 90%) is located upstream
of Lake Winnebago. About 1/3 of the total basin has become reforested.
Average annual flow ---Fox River from Lake Winnebago to Green
Bay ---116m3/sec-1. Typical annual maximum and minimum flows are 340 and
55 m3s-1 respectively.
Elevation drop --- 167.32 feet (51 meters) in only 39 miles of river.
Prior to dam construction, the river had many sizable rapids.
Impounded by 12 dams and navigable through 17 locks.
Waters from the Upper Fox River, Wolf River, and Lake Winnebago empty
into the Lower Fox River at the outlet of Lake Winnebago. Lake Winnebago
is the largest inland lake in Wisconsin, with an area of approximately
212 square miles (550 sq. km) and an average depth of 13 feet (4 meters).
Largest bay of Lake Michigan
Largest freshwater estuary in the world
Oriented in a NNE-SSW direction
Latitude & Longitude --- south end at city of Green Bay, 44°
31' N, and north end at Big Bay de Noc, 45°
Looking north toward the mouth of the Fox River
flowing into Green Bay.
Length --- 120 miles (193 km)
back to top
Mean width --- 14 miles (22 km)
Average width --- 23 miles (37 km)
Average depth of the extreme lower Bay --- 6.5 to 9.8 feet (2-3 m)
Mean depth --- 65 feet (20 m)
Maximum depth --- 176 feet (53 m), located 4 miles (6.4 km) west of
Area --- 186 square miles (4,212 square km)
Volume --- 11 cubic miles (70 square km)
Height --- about 580 feet above New York mean sea level (176 m), though
levels have fluctuated widely
Age --- about 10,000 years, since the last glaciers receded
Watershed --- drains approx. 15,625 square miles (40,000 square km).
One third of all land that drains into Lake Michigan drains through Green
Bay first (though the bay itself has only 7.9% of Lake Michiganís total
surface area). Two thirds of the Green Bay watershed is in Wisconsin, one
third in Michigan
Green Bay is open to Lake Michigan at the northeast side with Door County,
Rock Island, Washington Island and St. Martinís Island separating the two.
Temperature --- cools faster than Lake Michigan in the fall, and becomes
thermally stratified earlier in the summer. The southern bay is more than
7° C warmer than the northern bay, and 12°
warmer than deep lake water
Eleven rivers and streams drain into Green Bay. Of these there are only
5 of major importance. Three are in Wisconsin --- the Fox/Wolf Rivers,
Peshtigo River and Oconto River. Both Michigan and Wisconsin areas drain
into the Menominee, which forms the boundary between the two states. The
Escanaba is the only major river entirely in Michigan, with the Whitefish
and Ford Rivers of secondary importance. The Fox River is the most significant
river because of its volume and pollution load.
Additional pollution loads come from municipal sewage plants, urban
runoff and farmland runoff in the Lake Winnebago and lower Wolf River region.
While the Fox River is the major source of degraded water, there are localized
pollution problems in the Oconto, Peshtigo, Menominee and Escanaba Rivers.
The smaller streams contribute significant loads of silt and debris, which
vary in amount seasonally.
The northern bay has relatively high-quality (oligotrophic) waters,
while the lower, southern bay has low-quality (hypereutrophic) water quality
(though this has improved overall during the past 25 years.)
The region of the lower bay south of Long Tail Point, referred to as
the "inner bay," has been described as an extension of the Fox River due
to similar water quality features.
TRIBUTARIES OF GREEN BAY
The two major shipping ports on the bay are Escanaba, Michigan and Green
16,687 sq. km
117 cu. meters/sec
Green Bay is within the glaciated area of Wisconsin and Michigan. The
Wisconsin portion is within the ancient lake system. The bedrock of the
Green Bay area is paleozoic in age and composed of at least three formations,
the Niagara (Dilurian, dolomite) of Door Peninsula, the Maquoketa (Ordovician,
dolomitic shale) on the southeast shore, and the Platteville-Galena Group
(Ordovician, dolomite and limestone) on the western edge of the Bay. Other
important formations within the Bayís watershed are the Prairie du Chien
Group (Ordivician, dolomite), Cambrian sandstones and Precambrian granite
and undifferentiated igneous and metamorphic rocks.
The post glacial history of Green Bay is one of advancing and retreating
shorelines. 10,000 years ago, Lake Chicago, which occupied the present
Lake Michigan Basin, was at about 600 feet in elevation (183 m), about
20 feet (6 m) above the present stage. The Lake drained southward and through
the Chicago outlet. As the ice continued to retreat, the Lake Michigan
and Lake Huron basins combined through the Little Traverse Bay Lowlands.
The combined basins maintained an elevation of 605 feet (184 m) for almost
3,000 years. Distinct shoreline features developed during the period. At
the end of the Algonquin period, about 7,000 years ago, Green Bay drained
in four major steps until it was totally emptied. At least one beach may
be evident 90 feet (27 m) below the present lake level.
Sixty-seven hundred years ago, with the bay completely drained, the
west shore- rivers probably joined to form one great north flowing river.
With Lake Superior at a much higher elevation, over 1,000 feet (303 m),
a major drainage developed across Little Bay de Noc in Lake Michigan. This
steep-walled channel is two miles wide and 100 feet deep (30.3) m) and
extends across Northern Green Bay. That the bay filled rapidly to 605 feet
(183 m) about 4,500 years ago is evidenced by the fact that little major
deposition or erosion occurred in the former drainage channel.
back to top
Green Bay is best characterized as an estuary since it functions as
a nutrient trap, has exceptionally high biological productivity, and because
of the thermal and chemical differences between the water of its tributaries
and that of Lake Michigan. It resembles the Delaware Bay estuary on the
Atlantic Coast. The water in the bay has several characteristics important
to management strategies:
Fluctuating Water Levels --- Since 1860 when
records were started, there has been a variation of over 7 feet between
extreme high (1986) and low levels (1964), due to climatic variations.
To a very limited degree the water levels can be controlled at the major
inlet for Lake Michigan (Sault Ste. Marie) and through the southern outlet
of the Chicago canal. Seasonal low water usually occurs in January, with
higher levels occurring in June.
Seiches --- Because of its elongated shape,
Green Bay is subject to tilting, or basin oscillations, on a short-term
scale, similar to tides but not on a regular schedule. Imagine water sloshing
back and forth in a bathtub. These oscillations, or "seiches," (pronounced
"saysh ez") are caused by wind, sudden changes in barometric pressure,
currents and other physical factors. A normal seiche may change water levels
a foot or more in a few hours, three or four times a day. The seiches are
strong enough to reverse river flow up to 7 miles up from the mouth of
the Fox River. In 1966, one seiche was measured with flows at the river
upstream at a rate over 280 cubic meters per second
(10,000 cfs) In 1957, the East River (a tributary of the Fox) had a change
of 4.7 feet (1.33 m) in 17 hours, from a seiche pushing water upstream.
The bay is also slightly affected by a semi-diurnal lunar tide as well.
Currents --- Currents in the lower bay tend
to be counter-clockwise, moving southerly on the western side, then swinging
east and north. In addition, when the Fox River currents enter the bay
they immediately turn east, due to the coreolis effect of the earthís spin.
Historically, the river currents kept the east shore of lower Green Bay
flushed clean, with beautiful sandy beaches, while the west shore was quieter,
accumulated more soft sediments and generated vast cattail marshes and
wild rice beds. Some pockets in the lower bay have limited water movement.
While the water from the large portion of Green Bay does find its way into
Lake Michigan, the bay tends to have a hydrodynamic life of its own. When
the water does exit, the outflow is carried south along the Wisconsin shore
of Lake Michigan. During most of the year, the waters of the Fox River
and several smaller rivers that empty into the west side of the bay are
warmer than Lake Michigan, and therefore tend to remain on the surface.
Colder water from Lake Michigan enters at depth through several channels
at the north end of the bay. This two-layered system operates somewhat
like a conveyor belt, with the warmer, nutrient-laden surface water moving
northward, and the colder (generally cleaner) Lake Michigan water moving
southward at the deeper layers.
back to top
Residence Time --- The average residence time
of Fox River water, and any dissolved pollution in the lower half of the
bay, ranges from 100 to 160 days, depending on the rate of flow in the
the Fox River Watershed --- EPA site loaded with information and links
Friends of the Fox River Trail
--- This citizens organization formed recently to support the new pedestrian
path along the abandoned railway on the east bank of the river, from the
City of Green Bay to the City of DePere, then across farming country to
Baird Creek Parkway Preservation
Foundation --- Baird Creek is a tributary of the Fox River, largely
within the City of Green Bay boundaries. Many sections are heavily
forested with old growth trees and other valuable recreational space and
wildlife habitat. The Foundation is working to preserve more
sections to add to the Parkway for future public enjoyment.
Fox Communities Online --- A major
directory of websites from our area
Gerard Bertrand, Jean Lang, John Ross. "The
Green Bay Watershed - Past/Present/Future" Institute for Environmental
Studies, UW-Madison, UW-Sea Grant College Program, Technical Report #229,
Linda Weimer, et al, "Green Bay: Portrait of a Waterway."
Collection of articles in the Green Bay Press Gazette, reproduced by UW-Sea
Grant College Program, WIS-SG-79-130. 1979.
H.J. Harris, P.E. Sager, C.J. Yarbrough and H.J. Day,
"Evolution of Water Resource Management: A Laurentian Great Lakes Case
Study," International Journal of Environmental Studies, 1987, Vo. 29, pp.
Peyton L. Smith, Robert A. Ragotzkie, Anders W. Andren,
and Hallett J. Harris, "Estuary Rehabilitation: The Green Bay Story." Oceanus,
back to top