Here is some research that Liz has gathered on the tolerance ranges for a healthy, diverse stream ecosystem for students to use as a guide while analyzing your own findings:
Tolerance Ranges Document
Showing posts with label Resources. Show all posts
Showing posts with label Resources. Show all posts
Thursday, March 22, 2012
Friday, March 2, 2012
Ravine Maps
Ravines Map
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Map of Ravines in South Lake County
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| Contour Map of Ravine 7L Can you figure out which colors represent high elevations? Credit: Lei Wang, Park District of Highland Park |
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Drainage Area Map of Ravine 7L
Shows the three drainage areas (blue line) and drainage points (green dots) for the Ravine 7 Watershed. Which drainage area will have the most impervious surface, and what will this mean for surface runoff?
Credit: Lei Wang, Park District of Highland Park
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Research for "Want to Know"
“The Lake Michigan ravines of northeastern Illinois range from 10 to 75 feet in depth and extend as much as 2 miles inland from the lakeshore. The ravine systems are an important natural legacy, as they represent the only remaining natural drainage systems in the present-day Lake Michigan watershed in Illinois. Historically, almost 673 square miles of northeastern Illinois drained into Lake Michigan via the Chicago and the Calumet River systems and the coastal bluff/ravine systems (Map 1). By 1922, canals had diverted the majority of flow in both the Chicago and the Calumet River systems into the Des Plaines River watershed (within the Mississippi River basin) as a way to provide safe drinking water and alleviate flooding in the Chicago metropolitan area, and to allow for cargo traffic between the Great Lakes and the Mississippi River. The land area of Illinois currently draining to Lake Michigan covers only 88 square miles, or 12 percent of its extent at the time of Euro-American settlement. Of this remaining drainage area, over 50 square miles lie in Lake County, with ravines covering less than 1.6 square miles. The ravine systems are, therefore, both an important and uncommon resource for both Illinois and the Great Lakes watershed.”
Ravine Systems in the Lake Michigan Watershed, Illinois
More articles:
Coastal Erosion along the Illinois Coastal Zone
The Illinois Coast of Lake Michigan
Discovering the Benefits of On-site Stormwater Management
Ravine Definitions
Definitions for Ravine Restoration
Posted by Zach Kolman from Mr. Hill's Environmental
Science class
Riffles - A fast-flowing, shallow part of
a stream.
Gabian
baskets -
In civil engineering, gabion wall is a retaining wall made of
rectangular containers (baskets) fabricated of thick galvanized wire, which are
filled with stone and stacked on one another, usually in tiers that step back
with the slope rather than vertically. They may be used to direct the force of
a flow of flood waters around a vulnerable structure. Gabions are also used
as fish barriers on small streams.
Aeration - The process by which air is
circulated through, mixed with or dissolved in a liquid or substance.
Substrate - The earthy material that
exists in the bottom of a marine habitat, like dirt, rocks, sand, or gravel.
Dissolved
Oxygen -
A relative measure of the amount of oxygen that is dissolved or carried in a
given medium. It can be measured with a dissolved oxygen probe such as an
oxygen sensor or an optode in liquid media, usually water.
Turbidity - The cloudiness or haziness
of a fluid caused by individual particles (suspended solids) that are generally
invisible to the naked eye, similar to smoke in air.
Wednesday, February 22, 2012
“Scoop up a handful of sand on a North Shore beach and you are holding the sand washed down from the moraine of our last ice age. Pick up a rock and you are holding a remnant of glacial till carried here from Canada. The ravines and bluffs tell the evolution of our shoreline — and link us to our geologic past”
-Michael Chrzastowski, PhD, Chicago Wilderness, 2008
History of the Highland Park Moraines
Dr. Michael Chrzastowski, senior coastal geologist with the Illinois State Geological Survey, explains the geologic evolution of the area:
“About 14,000 years ago, the Lake Michigan lobe of the Laurentide Ice Sheet began to recede, leaving rings of glacial till called moraines (piles of clay, gravel, and sand) atop the bedrock. The Highland Park moraine, destined to become incised by the ravines, extended past our current lake’s boundaries and stood over 100 feet high.
“About 10,000 years ago, the weight of the still-retreating ice pushed down on the land so much so that it opened a lower-than-lake-level exit to the north, through Canada’s Ottawa River. The result: Lake Michigan’s water level dropped an astounding 250 feet in a very short time, exposing the older lakebed for 20 miles, to the shores of the now much smaller lake, which geologists call Lake Chippewa. Rain and melting snow quickly developed channels on the exposed lakebed floor. (Also interesting, a forest formed on the lakebed; tree stumps found at the bottom of today’s lake date to 8,300 years ago.)
“About 8,000 years ago, the lakebed streams’ headward erosion reached the Highland Park moraine. As streams touched the moraine, they washed out sand and gravel, cutting a V-shaped channel into the hill. Moraine erosion continued in two directions: run-off of rain and snow in streams from the top, plus “chewing” in from the bottom from the lakebed streams. And thus the ravines began to form. (Myth #2 says that glaciers formed the ravines; actually, glaciers formed the moraines, while streams formed the ravines.) The process was quick, lasting just 5,000 years, between 8,000 B.C. and 3,000 B.C. (This dispels Myth #3, which assumes that ravines are old— they’re actually quite young, geologically speaking.)
“As the glaciers at the northern end of the lake continued to melt, their weight decreased, allowing the land to gradually rise again, which closed off the water exits to the north. (This rebound continues today. Land around Hudson Bay continues to rise one meter per century.) Lake levels rose again, and by about 3,000 B.C., Lake Michigan had refilled close to today’s levels. Waves then chewed away at the moraine (which once extended farther east), forming the bluffs that we see today."
“About 14,000 years ago, the Lake Michigan lobe of the Laurentide Ice Sheet began to recede, leaving rings of glacial till called moraines (piles of clay, gravel, and sand) atop the bedrock. The Highland Park moraine, destined to become incised by the ravines, extended past our current lake’s boundaries and stood over 100 feet high.
“About 10,000 years ago, the weight of the still-retreating ice pushed down on the land so much so that it opened a lower-than-lake-level exit to the north, through Canada’s Ottawa River. The result: Lake Michigan’s water level dropped an astounding 250 feet in a very short time, exposing the older lakebed for 20 miles, to the shores of the now much smaller lake, which geologists call Lake Chippewa. Rain and melting snow quickly developed channels on the exposed lakebed floor. (Also interesting, a forest formed on the lakebed; tree stumps found at the bottom of today’s lake date to 8,300 years ago.)
“About 8,000 years ago, the lakebed streams’ headward erosion reached the Highland Park moraine. As streams touched the moraine, they washed out sand and gravel, cutting a V-shaped channel into the hill. Moraine erosion continued in two directions: run-off of rain and snow in streams from the top, plus “chewing” in from the bottom from the lakebed streams. And thus the ravines began to form. (Myth #2 says that glaciers formed the ravines; actually, glaciers formed the moraines, while streams formed the ravines.) The process was quick, lasting just 5,000 years, between 8,000 B.C. and 3,000 B.C. (This dispels Myth #3, which assumes that ravines are old— they’re actually quite young, geologically speaking.)
“As the glaciers at the northern end of the lake continued to melt, their weight decreased, allowing the land to gradually rise again, which closed off the water exits to the north. (This rebound continues today. Land around Hudson Bay continues to rise one meter per century.) Lake levels rose again, and by about 3,000 B.C., Lake Michigan had refilled close to today’s levels. Waves then chewed away at the moraine (which once extended farther east), forming the bluffs that we see today."
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