378 . 
DECLINE IN ELEVATION oF Low-WaATER SuRFACE, 1901 
é Av. slope 
Reach Hae (inches) 
per mile 
Chillicothe—foot Peoria Lake 18.3 0.26 
Chillicothe (mile 180.5)—Mile 171.0* 9.5 Not meas- 
urable 
Mile 171.0—170.5 0.5 2.40 
Mile 170.5—166.9 3.6 Not meas- 
urable 
Mile 166.9—165.5 1.4 0.85 
Mile 165.5—163.8 alt 0.70 
Mile 163.8—162.2 (foot of lake) 1.6 0.75 
averages just above and just below Peoria Lake, this is found to be less 
. than one fourth of the actual average continuous area flooded in each 
mile (379.9 acres); or, in other words, the river was on the average 
throughout this eighteen-mile section at those levels more than four times 
normal width. The ex-river or lake acreage per mile at the low water 
of 1901 figured in this way (379.9—80.0—299.9 acres per mile) in fact 
exceeded that found for any other sections of the river except two, viz., 
the 16.8 miles between Copperas Creek dam and Havana and the 42.5 
miles between Havana and the Lagrange dam. 
Lakr AND Ponp Acreage, Low Water, 1901 
(AS IN VALLEY BEFORE LEVEES) 
Lake and 
Interval pond 
Reach miles acreage 
per mile 
Chillicothe to foot Peoria Lake 18.5 299.9 
Foot Peoria Lake to Pekin 9.0 113.6 
Pekin to Copperas Creek dam 16.2 219.0 
Copperas Creek dam to Havana 16.8 472.1 
Havana to Lagrange dam 42.5 382.4 
_ Lagrange dam to Florence 21.9 219.6 
Florence to Kampsville dam 24.2 180.0 
Kampsville dam to Grafton 31.4 86.9 
Depths in the river channel between Chillicothe and the foot of 
Chillicothe Island (0.9 mile below Chillicothe, the point where the ex- 
pansion into the wide waters of Peoria Lake begins) were 22.5 to 24 feet 
at the low water of 1901, and have been about four and a half feet more 
than those figures at recent low gages. The channel through the lake at 
the low water of 1901 varied in depth from about seven to a little over 
twenty feet; and at recent low levels from over eleven to over twenty- 
four feet. 
* Mile figures represent miles above Grafton. 
