The game may be over: Asian carp beyond electric barriers

Is there not a natural connection, possibly intermittant, between the Mississippi and Great Lakes drainages just northwest of Chicago?

Not that I'm aware of, but maybe a Chicagoan can chime-in here.

Brian

Is there not a natural connection, possibly intermittant, between the Mississippi and Great Lakes drainages just northwest of Chicago?

Not that I'm aware of (either before or after the reversal of all local rivers). I guess that all depends on how you want to define "intermittent". I would imagine it's possible to flood enough to connect the Des Plaines with the Chicago River (perhaps near Park Ridge) but a flood the likes I've never encountered yet a flood that has or is likely to happen at some point. I would also guess if Chicago were not as developed as it is, a connection of the two waters would require a flood of monumental proportions.

Below images from Wikipedia:

The area of potential connection would be the swamp Chicago is built up on rather than a free flowing stream. The built up nature of Chicago may be what blocks natural corridors.

How much of a flood is required to connect Des Plains and Chicago River drainages?

Edited by centrarchid, 13 January 2010 - 11:33 AM.

How much of a flood is required to connect Des Plains and Chicago River drainages?

Not really certain but something along the lines of rain for 40 days and 40 nights.

The area of potential connection would be the swamp Chicago is built up on rather than a free flowing stream.

That would be more likely to the south of the city combining the once vast Lake Calumet with the once Grand Marsh of the Kankakee but just speculation without precise topographic information.

Quite a bit (like 40 days and 40 nights, I liked that Uland ). Lake Chicago was 23 feet higher than the contemporary lake level. The Chicago River drained the newly exposed lake bed, the Des Plains was an entrenched inter-morainal drainage that connected on scoured bedrock in the outflow channel of Lake Chicago. There are also beach ridges to the east that would prevent their connection.

There's a pretty good write up of the soils and associated plant communities in Plants of the Chicago Region (Swink & Wilhelm 1994). I'm sure if you look around online you can find some info too. There's quite a bit of info on the Indiana Geologic Survey site, but it of course focuses on the Calumet and Indiana portions of the Grand Prairie and Grand Marsh complexes.

Todd

Quite a bit (like 40 days and 40 nights, I liked that Uland ).

Cute but useless. Greater than a 500 year flood event (sometimes little meaning as well) or ignorance of connectivity provided by borrow pits and sewers.


What about stream capture risks farther north than the area in question? Your efforts to keep the bighead and silver carps out of Lake Michigan will last more than your lifetimes or professional careers. what will be the next risk area?