Chicago Portage

The Chicago Portage connects the watersheds (BrE: drainage basins) and the navigable waterways of the Mississippi River and the Great Lakes. It crosses the continental divide that separates the Great Lakes and Gulf of St. Lawrence watersheds from the Gulf of Mexico watershed.^[1]

Near Chicago, the St. Lawrence Seaway divide runs less than a mile from the shores of Lake Michigan, and is at places only 14 feet (4.3 m) higher than the water level in the lake. A breach of the ridge could potentially cause the Great Lakes to flow southwards to the Gulf of Mexico.

The portage was revealed to Europeans in 1673 when the French Canadian explorers, Louis Joliet (Jolliet) and Father Jacques Marquette, were canoeing upstream on the Mississippi River. They were guided to the portage by native Indians and continued along the Illinois and Des Plaines Rivers. Near where the Des Plaines was separated from the Chicago River was a swampy area named Mud Lake, Seasonally, this was a shallow waterway or a muddy slough of eight miles. This connected the Des Plaines to the Chicago River, which then flowed into Lake Michigan.

At the time, the Chicago Portage was the most strategic location in the interior of the North American continent and in particular between the French cities of Montreal and New Orleans. Control of the Portage was critical if the French were to contain English expansion in the New World. According to Joliet, a canal of "half a league'' (about 2 miles (3.2 km), 3 km) across the Chicago Portage would allow easy navigation from Lake Erie to the Gulf of Mexico.^[2]

In 1848, the Illinois and Michigan Canal was opened, breaching the water divide and enabling navigation between the two waterways. In 1900 it was replaced by the larger Chicago Sanitary and Ship Canal. After the Chicago River was diverted to the new canal, the Mississippi watershed is now separated from the Great Lakes by only a few downtown Chicago locks. The quantity of water allowed to pass (and thus diverted from the St. Lawrence River) is regulated under international treaty between the U.S. and Canada.

The Chicago Portage National Historic Site marks the western end of the portage on the Des Plaines River.

Mississippi Valley watershed and Chicago   Great Lakes Basin and St. Lawrence watershed   The Illinois and Michigan Canal breached the water divide in 1848. It was largely replaced by the Chicago Sanitary and Ship Canal (right) in 1900

References

1. ^ http://www.chicagoportage.org/synopsis.htm
2. ^ http://www.encyclopedia.chicagohistory.org/pages/993.html

See also

• Valparaiso Moraine
• Eastern Continental Divide

External links

• Jolliet and La Salle's Canal Plans at Encyclopedia of Chicago
• The Continental Divide in Oak Park
• Carnegie Mellon University Libraries: Chicago Portage Ledger
• Chicago Portage History