W***n
发帖数: 11530 | 1 Flood Control and Drainage
The Chicago area is topographically dominated by the glacial Lake Chicago
plain. This plain encompasses the Chicago River, Des Plaines River, and the
Calumet River. Early explorers discovered the Chicago Portage, an area
within Mud Lake that was only 15 feet above the level of Lake Michigan and
on the watershed divide between the Mississippi River basin and the Great
Lakes basin.
The Chicago area experienced many early drainage challenges. The natural
condition was swampy. Chicago streets were poorly drained and muddy. The
level of Lake Michigan was only two feet below the river banks, making
subsurface drainage ineffective.
In 1834, the first attempt to solve the sanitation problem of Chicago
included a drainage ditch dug down State Street and emptying into the
Chicago River. Later, the city of Chicago raised streets, then buildings, 8
to 10 feet above natural ground level. This helped to drain the streets and
to get the sewage to the river more efficiently, but the river could not
cleanse itself of the sewage due to the high level of Lake Michigan.
The Illinois & Michigan Canal, completed in 1848, flowed from present-day
Summit to LaSalle. From 1861 through 1870, the city of Chicago paid to
operate the Bridgeport pumps an additional 45 days per year to flush sewage
from the Chicago River and away from the lake.
The 1872 flood diverted almost all the Des Plaines River flows into the
Chicago River through the Ogden-Wentworth Ditch, causing significant
pollution within the Chicago River when the sewage could no longer be sent
downstream. A dam was constructed across Ogden-Wentworth Ditch to prevent
future diversions of Des Plaines River flows.
In 1885, a large rainfall washed sewage and refuse out of Chicago and the
Chicago River into Lake Michigan, polluting the city's water supply. The
Illinois General Assembly authorized the establishment of the Sanitary
District of Chicago in 1889 to implement the construction of the Sanitary
and Ship Canal to carry away waste from the city and to dilute it as it
flowed downstream. Construction began in 1892, and flow through the canal
began January 17, 1900. The North Shore Channel enlargement, begun in 1907
and completed in 1910, diverted more lake water to aid in dilution, and the
Chicago River was enlarged in 1912. Construction of the Cal-Sag Channel
began in 1911 and was completed in 1922, reversing the flow of the Calumet
River away from Lake Michigan. A Supreme Court decree in 1933 ordered the
construction of the Chicago River lock and controlling works, which was
completed in 1938.
Areas outside the city of Chicago experienced many drainage alterations as
well. The Illinois Farm Drainage Act of 1879 established the authority to
create drainage districts, marking the beginning of a period of significant
drainage modifications in agricultural areas. By 1929, 88 drainage districts
covered 177,595 acres of the Chicago River, Little Calumet River, Des
Plaines River, DuPage River, and Fox River basins. By 1971, 180 drainage
districts were listed in an “Inventory of Drainage and Levee Districts”
within Cook, DuPage, Lake, McHenry, Kane, and Will Counties.
As more land became developed with housing, streets and shopping areas, a
greater amount of runoff from this developed ground ran to the sewers. The
stormwater runoff mixed with sanitary sewage and became combined sewage.
Suburban communities developed after World War II realized the value of
separate sewer systems to handle sanitary sewage and stormwater runoff.
Suburban communities have installed countless miles of storm sewers to
accommodate modern drainage needs, replacing the earlier systems provided by
drainage districts.
Studies in the late 1960s recommended the Tunnel and Reservoir Plan (TARP),
known as “Deep Tunnel,” as a means to solve this problem. TARP tunnels
include the Mainstem, Calumet, Des Plaines, and Upper Des Plaines systems,
totaling 109 miles of tunnels. These tunnels capture sewer overflows that
had been discharging into rivers and streams. TARP's three reservoirs, when
completed, will provide significant flood control.
Flooding of rivers in the Chicago area is a natural phenomenon. Agricultural
areas flood along with natural wetlands. The magnitude of these floods and
the effects upon humans grew as the metropolitan area developed. Flood
events of historical significance have occurred across the region during
1849, 1855, 1885, 1938, 1952, 1954, 1957, 1961, 1973, 1979, 1986, 1987, and
1996. Most record-setting flood stages and discharges in the region have
been recorded since 1948.
Flood control and watershed planning in the Chicago region is managed by a
group of federal, state, and local agencies. These include the U.S. Army
Corps of Engineers, the U.S. Department of Agriculture, Natural Resource
Conservation Service, the U.S. Environmental Protection Agency, the Illinois
Department of Natural Resources, the Illinois Office of Water Resources,
the Metropolitan Water Reclamation District of Greater Chicago, and storm
water management agencies in each of the region's counties.
By the early 1980s several watershed plans were developed to address flood
problems along the North Branch Chicago River, Upper Des Plaines River,
Lower Des Plaines Tributaries, Poplar Creek, Upper Salt Creek, and the
Little Calumet River. These plans will eventually implement 43.9 miles of
channel modifications and 41,128 acre-feet (13.4 billion gallons) of
floodwater storage facilities, including the Tunnel and Reservoir Plan.
Flooding remains a serious problem along the main channel of the Des Plaines
River and the Little Calumet River and many smaller streams. A 1998
estimate puts annual flood damages at $41,459,000 in the Chicago area,
affecting nearly 20,000 homes and businesses.
Local, state, and federal agencies and individuals have become increasingly
aware of the unmitigated impacts of urbanization on drainage and flooding.
The Metropolitan Water Reclamation District implemented the first stormwater
detention ordinance in 1972. This ordinance required new developments to
detain a portion of the increased runoff and to restrict the outlet capacity
of the detention basin to a predevelopment discharge. It has now become
standard practice to provide stormwater detention within new subdivisions to
control the rate of runoff to predevelopment rates.
The 1986 flood was triggered by widespread regional rainfall with varying
intensity and duration, which had been preceded by two weeks of nearly
continuous rain falling across northern regions of the Des Plaines, North
Branch Chicago, and Fox River watersheds. Flooding in rivers and streams
across Lake, McHenry, northern Cook, northern DuPage, and northern Kane
Counties resulted. The 1987 flood was generated by localized high-intensity
and shorter duration rainfall which dropped up to 13 inches of rainfall in
less than 24 hours, largely in Cook and DuPage counties. The 1986 and 1987
floods generated enough public awareness of the continued problems of
drainage and flooding for the Illinois General Assembly to pass legislation
authorizing the formation of countywide stormwater management programs.
Arlan R. Juhl
Bibliography
Barker, Bruce. Lake Diversion at Lake Michigan. Illinois Department of
Transportation, Division of Water Resources, 1985.
Cain, Louis P. Sanitation Strategy for a Lakefront Metropolis: The Case of
Chicago. 1978. | W***n
发帖数: 11530 | 2 It just takes a lot of lessons-learned, experience, time, money, sound
engineering and manaagement to solve flooding problem of a huge metropolis..
... | W***n
发帖数: 11530 | 3 Especially for a 60 years downpour. | R***r
发帖数: 3519 | 4 你自己都说教训可以被学习，ｔｇ就不会，对不？你鸭的家人也在国内，需要自救！
the
【在 W***n 的大作中提到】
: Flood Control and Drainage
: The Chicago area is topographically dominated by the glacial Lake Chicago
: plain. This plain encompasses the Chicago River, Des Plaines River, and the
: Calumet River. Early explorers discovered the Chicago Portage, an area
: within Mud Lake that was only 15 feet above the level of Lake Michigan and
: on the watershed divide between the Mississippi River basin and the Great
: Lakes basin.
: The Chicago area experienced many early drainage challenges. The natural
: condition was swampy. Chicago streets were poorly drained and muddy. The
: level of Lake Michigan was only two feet below the river banks, making
|
|
