St. Croix River (Wisconsin–Minnesota)

The St. Croix River ( ; ), also known in Dakota as Hoġan Wanḳe Kin, is a tributary of the Mississippi River, about long, in the U.S. states of Wisconsin and Minnesota. The lower of the river form the border between Wisconsin and Minnesota. The river is a National Scenic Riverway under the protection of the National Park Service. A hydroelectric plant at the Saint Croix Falls Dam supplies power to the Minneapolis–Saint Paul metropolitan area.

Geography and hydrography

The St. Croix River rises in the northwestern corner of Wisconsin, out of Upper St. Croix Lake in Douglas County, near Solon Springs, approximately south of Lake Superior. It flows south to Gordon, then southwest. It is joined by the Namekagon River in northern Burnett County, where it becomes significantly wider. A few miles downstream the St. Croix meets the boundary between Minnesota and Wisconsin, which it demarcates for another until its confluence with the Mississippi River.

left|thumb|Aerial photo near [[Prescott, Wisconsin, where the clearer waters of the St. Croix meet the muddier Mississippi River.]]

Other major tributaries include the Kettle River, Snake River, and Sunrise River joining from the west, and the Apple River, Willow River, and Kinnickinnic River joining from the east. Just below Stillwater, Minnesota the river widens into Lake St. Croix, and eventually joins the Mississippi River at Prescott, Wisconsin, approximately southeast of St. Paul, Minnesota.

Geomorphology

The presence of older glacial deposits within the St. Croix River basin proves that the Laurentide Ice Sheet has repeatedly glaciated this region during the Pleistocene Epoch. Within this region these older deposits consist of gray calcareous tills associated with glaciofluvial yellowish-brown sand and gravel and glacial lacustrine silts and clays of the Pierce Formation and overlying reddish-brown tills and associated sand and gravel of the River Falls Formation. Any glacial landforms associated with these earlier glacial deposits have been destroyed by erosion. These earlier deposits occur as erosional remnants either capping hills or buried by the latest advance of the Laurentide Ice Sheet over this area during the Last Glacial Maximum.

The drainage basin of the St. Croix River last deglaciated between about 19,000 and 14,000 BP calibrated (16,000 and 12,000 <sup>14</sup>C uncalibrated). During this time, the Superior Lobe retreated from the maximum extent of the Superior Lobe at the Emerald moraine northeastward to Thompson and Nicherson moraine complex at the edge of the Lake Superior basin. During the retreat of the Superior Lobe, a blanket of reddish-brown tills containing beds of fine sand and silt was left behind by the melting of the retreating ice sheet. During glacial retreat, meltwater drainage from the intermediate St.Croix moraine established the precursor to the St. Croix River.

The retreat of the Superior lobe into the Lake Superior basin created small, proglacial lakes. Later, these lakes coalesced to form a large proglacial lake called proglacial Lake Duluth, within the western Superior basin. The multiple lake levels of proglacial Lake Duluth included the Duluth level and an older and smaller epi-Duluth level. At first, glacial meltwater drained from the epi-Duluth level and a smaller precursor proglacial lake, named Lake Nemadji through the Moose Lake (Portage) outlet into the Kettle River and into the St. Croix River. The flow of glacial meltwater from glacial Lake Nemadji and Lake epi-Duluth during the retreat of the Superior Lobe caused the rapid entrenchment of the St. Croix River and formation of a strath terrace, known as the Chengwatana surface. As the Superior Lobe retreated, the Duluth level was established when another outlet, the Brule outlet, opened and the Moose Lake outlet was abandoned. The opening of the Brule outlet allowed a massive and sudden outflow of glacial meltwater through the Brule outlet and down St. Croix River and excavation of a deep inner channel, which includes the Dalles, into the Chengwatana surface. This massive flow of meltwater also created the giant potholes of Interstate Park between 10,800 and 10,600 BP calibrated. The Brule outlet was abandoned when Lake Superior Lobe retreated from the Keweenaw Peninsula and opened lower eastward draining outlets. This caused the Duluth level to drop abruptly to post-Duluth levels and water to cease flowing into Brule outlet and down the St. Croix River. The cessation of water outflow through the Brule outlet disconnected the St. Croix River from the Lake Superior basin and created the northward flowing Bois Brule River.

Conservation efforts

The St. Croix River was one of the original eight rivers to have significant portions placed under protection by the National Wild and Scenic Rivers Act of 1968. The upper reaches of the river in Wisconsin below the St. Croix Flowage, downstream from its source, as well as the Namekagon River, are protected as the St. Croix National Scenic Riverway. The free-flowing nature of the river is interrupted only by the hydroelectric Saint Croix Falls Dam operated by the Northern States Power Company at St. Croix Falls, Wisconsin.

The lower below the dam, including both sides of the river along the Minnesota-Wisconsin border, were protected as part of the Lower St. Croix National Scenic Riverway. This area includes the Dalles of the St. Croix River, a scenic gorge located near Interstate Park, south of St. Croix Falls, Wisconsin.

Although the addition of an interstate bridge connected to MN Highway 36 was objected to by residents, nearby communities, conservation groups, and the National Park Service, construction of the bridge was authorized by amending the Wild and Scenic Rivers Act of 1968. Light and noise pollution are concerns of those opposed to the bridge, who cites the original act that kept such activity to the south along the Interstate 94 corridor. The St. Croix Crossing bridge was ultimately completed in August 2017.

The Wild Rivers Conservancy of the St. Croix & Namekagon is a watershed-wide non-profit advocating for conservation throughout the watershed. Founded in 1911 as an all-volunteer citizens group, it has evolved into a staffed, mature nonprofit organization and official "friends group" of the St. Croix National Scenic Riverway. Its mission is to inspire stewardship to forever ensure the rare ecological integrity of the St. Croix and Namekagon Riverway.

thumb|St Croix River, MN

Naming

thumb|St. Croix River Dalles at [[Interstate State Park, Wisconsin.]]

Father Louis Hennepin wrote in 1683, from information probably provided by Daniel Greysolon, Sieur du Lhut: "There is another River which falls ... into the Meschasipi ... We named it The River of the Grave, or Mausoleum because the Savages buried there one of their Men ... who was bitten by a Rattlesnake." In the original French, this is translated as "Rivière Tombeaux".

Jean-Baptiste-Louis Franquelin's 1688 map recorded a "Fort St. Croix" on the upper reaches of the river. The name "Rivière de Sainte-Croix" was applied to the river sometime in 1688 or 1689, Downstream of its confluence with the Namekagon, the Ojibwa renamed the river as Gichi-ziibi (Big River) or Okijii-ziibi (Pipestem River)

At the time of the European settlement of the valley, Dakota and Ojibwe were engaged in a long and deadly war with each other. Consequently, the portion of the river below the confluence with Trade River is called Jiibayaatig-ziibi (Grave-marker River) in the Ojibwe language, After the end of the French and Indian War in 1763, British traders entered the area and grew in numbers and influence with the help of the powerful North West Company.

It was along the banks of the St. Croix, in the milltown of Stillwater, that the state of Minnesota was first proposed in 1848.

Cities and towns

Afton, Minnesota
Bayport, Minnesota
Danbury, Wisconsin
Gordon, Wisconsin
Houlton, Wisconsin
Hudson, Wisconsin
Lake St. Croix Beach, Minnesota
Lakeland, Minnesota
Lakeland Shores, Minnesota
Lindström, Minnesota
Marine on St. Croix, Minnesota
North Hudson, Wisconsin
Oak Park Heights, Minnesota
Osceola, Wisconsin
Pine City, Minnesota
Point Douglas, Minnesota
Prescott, Wisconsin
St. Croix Falls, Wisconsin
St. Marys Point, Minnesota
Scandia, Minnesota
Solon Springs, Wisconsin
Somerset, Wisconsin
Stillwater, Minnesota
Taylors Falls, Minnesota

Bridge crossings

Significant bridge crossings of the St. Croix River are listed below, ordered from source to mouth.

Scott Bridge in Douglas County, Wisconsin.
County Road T bridge in Douglas County, Wisconsin.
C.C.C. Bridge in Burnett County, Wisconsin.
Wisconsin State Highway 35 bridge near Danbury, Wisconsin.
Minnesota State Highway 48 to Wisconsin State Highway 77 bridge near Danbury, Wisconsin.
Minnesota State Highway 70 to Wisconsin State Highway 70 bridge near Grantsburg, Wisconsin.
U.S. Highway 8 bridge between Taylors Falls, Minnesota and St. Croix Falls, Wisconsin.
Minnesota State Highway 243 bridge at Osceola, Wisconsin.
Soo Line High Bridge north of Stillwater, Minnesota. This private, rail-only bridge is long and above the river. It roughly marks the northern limit of zebra mussel infestation in the St. Croix.
The Stillwater lift bridge, built 1931, between Stillwater, Minnesota and Houlton, Wisconsin.
St. Croix Crossing bridge near Stillwater, Minnesota and Houlton, Wisconsin.
Union Pacific Railroad swing bridge at Hudson, Wisconsin
Interstate 94 bridge at Hudson, Wisconsin.
Prescott Drawbridge (U.S. Highway 10) at Prescott, Wisconsin.
BNSF Railway lift bridge at Prescott, Wisconsin.

Commerce and recreation

thumb|150px|[[William O' Brien State Park ]]

The St. Croix is a popular recreational river. Common uses include boating, fishing, camping and canoeing. Highways along both sides of the river offer scenic drives punctuated by small towns offering restaurants, shopping (especially antiques, books and gifts), bed and breakfasts, historical tours and other common tourist activities.

Public lands along the St. Croix River include:

Governor Knowles State Forest (Wisconsin)
Saint Croix State Forest (Minnesota)
Saint Croix State Park (Minnesota)
Chengwatana State Forest (Minnesota)
Wild River State Park (Minnesota)
Interstate Park (Minnesota and Wisconsin)
William O'Brien State Park (Minnesota)
Afton State Park (Minnesota)
St. Croix Boom Site (Minnesota)

References

External links

Saint Croix National Scenic River (National Park Service)
Detailed River Maps (National Park Service)
St. Croix River Association