Friday, February 17, 2017

The Natural and Unnatural Evolution of the Skokie Lagoons.

The Skokie Lagoons are a nature preserve on the Skokie River that extends from Glencoe to Winnetka and is owned and managed by the Forest Preserve District of Cook County (FPDCC). Within the system are seven inter-connected lagoons totaling 190 acres that are surrounded by floodplains and uplands. Water flows from north to south through the Chicago Botanic Garden into the Skokie Lagoons and south to the north branch of the Chicago River. The lagoons have a long evolutionary history going back to Pleistocene age continental glaciation.

The North Shore uplands, lowland marshes, ravines and Lake Michigan are all products of the last ice age. About 14,000 years ago, global warming caused the Laurentide icecap to retreat, leaving Glacial Lake Chicago (more than 60 feet above the present Lake Michigan). The glacier also left a topography of lake border moraines (low hills) separated by valleys and marshes that now include the Des Plaines River and the west fork (through Glenview), middle fork (through Northfield) and east fork or Skokie River of the north branch of the Chicago River. As lake levels fell, extensive wetlands developed in the valleys; the largest (approximately 20 miles long and ¼ to 1 mile wide) was the Skokie Marsh. To the east, the Highland Park Moraine, deposited by the Wisconsinan Glacier, separated the Skokie Marsh from Glacial Lake Chicago, now Lake Michigan.
Flooded Winnetka 1924.
Ridge Avenue in Winnetka lies along the crest of the Highland Park Moraine that slopes gently east and west. Glacial meltwater flowed eastward into Lake Michigan through stream valleys cut into the moraine clay deposits. In the marshes to the west, a diverse wetland plant community developed, including marsh grasses and wild rice that supported a robust community of fish and mammals and was also an important stop-over for migratory water fowl. Woolly mammoths and bison were also known to be residents of this region. It is said that Potawatomi Indians called the marsh the Kitchi-wap choku (CheWab Skokie on early maps) that roughly translates to “great marsh.” Since the area was subject to flooding, the first European settlers took a cue from the Potawatomi and used the land primarily for hunting and fishing.

Frank Windes, Winnetka Village Engineer from 1898 to 1940, reminisced about the marsh of his childhood in a talk to the Masonic Club in 1933:
There were great flocks of wild geese, ducks and wild swans. In the wet woodlands were to be found snipe, plover, woodcock and partridge. In the summer the plover, killdeer, bobolink, meadow lark, marsh wren and many of the waders were found in great numbers. Coon, mink, rabbits, muskrat and weasels were found, and we had great fun hunting with our old muzzle-loading shotguns. It was bare of trees, except for a few straggling willows and a wooded island or two; it was very wet most of the year; and now and then large tracts of “floating bogs” dangerous to walk across in flood times… The wild flowers grew in great profusion. Pond lilies were found in some of the ponds, wild strawberries, grapes, elderberries, cherries and plums grew in the bordering woods and meadows and on the “islands.”
Fishing was easy, according to Windes:
As small boys we would build two small dams across the Skokie stream. We would wade in the stream and beat the water with sticks, scaring the fish between our 2 dams. After we had some 20 to 30 good sized bass, pickerels, catfish and perch enclosed, we would close the dam, and then shovel out the fish, and everyone in town had a fine mess of fresh fish. The skating was wonderful. We could use iceboats, and skate all the way from Winnetka to the Wells St. Bridge in Chicago.
In the late 19th century, floods and mosquitoes were a chronic problem in the Skokie Marsh. Settlers dug drainage channels in sections of the marsh in order to expand “useful land” for grazing and farming. These attempts to improve the land had a negative consequence. Peat deposits from the newly-drained marsh regularly caught fire, blanketing neighbors with dense smoke.

Flooding continued and in 1884, the Skokie Ditch was constructed from the Skokie Marsh, eastward along Willow Road, through Indian Hill and Kenilworth to Lake Michigan. Legal opposition and loss of funding killed the project before it could be dug deep enough to fully drain the marsh.

Two decades later, Frank Windes formulated plans for turning the swampy Skokie Marsh into a lagoon system and presented them to Daniel Burnham and the Chicago Plan Commission for inclusion in the 1909 Plan of Chicago. Burnham said he was “many years ahead of the game; wait, some day this will be taken up; not now young man.” It wasn’t until 1933, after a half century of unsuccessful attempts to “drain the swamp” that President Franklin Roosevelt approved the creation of the Skokie Lagoons as a Civilian Conservation Corps (CCC) project along with seven others in Illinois. Winnetkan Harold Ickes, FDR’s Secretary of the Interior, is credited with development of the project.
Plans, Development of the Skokie Lagoons, Forest Preserve of Cook County.
CLICK MAP TO VIEW IN FULL SIZE.
The FPDCC had been buying up land in and around the marsh with the intention of flood control and creation of a waterfowl refuge and recreational area. About 4 million cubic yards of earth was excavated and landscaped by more than a thousand workers. It was the largest CCC project in the United States. The plan—completed in 1942—includes lakes, floodplains, connecting channels, flood control dams and perimeter ditches to divert storm water around the lagoons.

In 1968, the Chicago Botanic Garden was carved out of the north section of the Skokie Lagoons between Dundee Road and Lake Cook Road. Designed by landscape architect John O. Simonds, the Botanic Garden includes nine islands and 60 acres of water. Owned by FPDCC and managed by the Chicago Horticultural Society, it is a world-renowned living plant museum with 25 display gardens surrounded by four natural habitats.

Although peat fires were eliminated and flooding was reduced, by 1979 problems with siltation of the lagoons and untreated sewage spurred FPDCC to new action. The FPDCC and the Northeastern Illinois Planning Commission implemented a plan to divert treated wastewater around the lagoons. In addition, over one million cubic yards of sediment were dredged from the lagoons between 1988 and 1993.

Following the dredging, 40 tons of invasive carp were removed and native and sport fish restored to the deeper (up to 12 feet) and cleaner lagoons. Fishermen are now a common sight at the Willow Road dam and boaters regularly enter the lagoons at Tower Road.

Today, the biggest threats in the more than 540 acres of floodplains and uplands in the Skokie Lagoons are invasive plants: overstory trees and garlic mustard in the floodplains, buckthorn in the uplands, and tall perennial reeds in the diversion ditches. Although peat fires have been eradicated, dead trees in the uplands are becoming a fire hazard. FPDCC and Chicago Audubon Society volunteers have been actively working to rid the area of buckthorn and garlic mustard, clear brush and restore native plant species including grasses, sedges and wildflowers.

The Skokie Lagoons have transformed marshes into ponds and parkland, eliminated peat fires and greatly reduced the mosquito problem. But new homes built on land that was once marsh flood-plain still flood occasionally. In an effort to better control flooding, the Village of Winnetka is considering construction of a storm sewer system consisting of an eight-foot-wide pipe that would extend east to Lake Michigan—an underground version of the Skokie Ditch.

The evolution of the Skokie Lagoons is not complete. The construction of levees and dikes on the Mississippi River for flood control and navigation resulted in new problems that may not have been anticipated by the early planners. As exemplified by the Chicago Botanic Garden, close attention to detail and plenty of funds will assure the vision of sustainability. 

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