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Illinois Natlrai. History Survey Bulletin 



Vol. 28, Art. 2 



At the time of settlement of Cham- 

 paign County, very little soil eroded from 

 the prairie and timber areas, but intensive 

 farming made erosion a serious, constant 

 threat even in the nearl> flat or gently 

 sloping lands of Champaign County. As 

 the native vegetation was removed and 

 the soil directly exposed to rain and wind, 

 the soil became compact and less absorbent, 

 causing more rapid runofif, accompanied 

 by the loss of rich topsoil. The inadequacy 

 of soil conservation practices had adverse 

 effects upon the streams and contributed 

 to more frequent floods followed by seri- 

 ously low water levels. The eftects of soil 

 erosion and the need for intensive con- 

 servation methods are not fully appreci- 

 ated by many Champaign County farm- 

 ers. Few grainfields are farmed on the 

 contour, strip cropping is rare, and grass 

 waterways are maintained in relatively 

 few of the cultivated fields. Farm animals 

 are permitted to graze the stream banks 

 and thereby contribute to serious erosion 

 and siltation. 



Population, Urban, and Industrial 

 Developments 



During the first half of the twentieth 

 century, striking changes in land use in 

 Champaign County were brought on by 

 the increasing human population. In 1900, 

 the census reported 47,622 people residing 

 in the county; in 1930, 64,273; in 1960, 

 132,436. The trend has been toward ur- 

 banization; in 1900, 31.1 per cent of the 

 population lived in urban areas and, in 

 I960, 75.6 per cent. Although there are 

 about 26 cities and villages in the county, 

 only Champaign-Urbana, Rantoul, and a 

 few others have increased in population. 

 Some of the small villages in the count\ 

 have remained static in population or have 

 even declined. The changes in size of 

 urban areas is illustrated by fig. 6, which 

 shows the village limits of the 1870's in 

 red and the recent limits in black. 



A considerable acreage of farmland has 

 been usurped by urban and surburban de- 

 velopment. The total number of acres in 

 cultivation was roughly the same between 

 1900 and 1928 and was considerably 

 greater than it is today. Since 1928. 

 cleared land, particularly that marginal 

 to cities and villages, has been pressed 

 into nonagricultural uses. Alany areas 



that were once farmed now are covered by 

 modern schools, grain storage units, and 

 industrial developments; other large land 

 areas now are occupied by Chanute Air 

 Force Base and the campus of the Uni- 

 versity of Illinois. These lands are per- 

 manently out of production of farm crops. 

 The vast network of roads, including sev- 

 eral major highways that transect the 

 county, occupies a large and e\er-increas- 

 ing area. 



A highly developed road system has 

 made Champaign County ideally suited 

 for the study reported here because roads 

 are laid out, orderI\' and regularly, paral- 

 lel to each other at mile or half-mile in- 

 tervals throughout the county. All streams 

 could be sampled con\eniently at almost 

 any point, and electrofishing and other 

 heavy collecting gear could be transported 

 by automobile almost to the water's edge. 



Stream Drainages and Courses 



The stream drainages of Champaign 

 County can be summarized as follows. 

 Six rivers have headwater channels in the 

 county, four of which (Salt Fork, Em- 

 barrass, Kaskaskia, and Little \'ermilion) 

 actually originate within the county. All 

 of the drainages are separated by moraines, 

 except the Sangamon and Salt Fork ; dur- 

 ing times of flood, headwaters of the San- 

 gamon and Salt Fork may connect, al- 

 though connection occurs much less fre- 

 quently now than formerly. The total 

 drainage area (in square miles) of each of 

 these rivers within the county is as fol- 

 lows: Sangamon 277, Salt Fork 346, Mid- 

 dle Fork 69, Embarrass 138, Kaskaskia 

 168, and Little Vermilion 40. A few 

 smaller streams flow out of the county, 

 but each joins one of the six larger rivers 

 a short distance beyond the county border. 

 The relationships of the streams to the 

 larger rivers are shown in fig. 5. 



The total drainage area (in square 

 miles) of the main course of each of these 

 rivers at the point the river leaves Cham- 

 paign Countv is as follows : Sangamon 

 388, Salt Fork 307, Middle Fork 241, 

 Embarrass 106, Kaskaskia 98, and Little 

 Vermilion 28. These figures include up- 

 per reaches of those rivers that rise out- 

 side the county. 



Water Discharge. — Annual average 

 discharge records for two gaging sta- 



