200 
waters a volume of sewage equal to the pumpage, though their 
imperfectly developed systems of drainage, combined with the 
surface run-off, carry some sewage to the stream. 
POPULATION AND PUMPAGE IN CITIES WITHOUT SEWAGE SYSTEMS. 
City Population in 1890| Daily Pumpage Remarks. 
: in gal. 
Lilinots 
Batavia 3,543 2,500 1,500— 3,500 gallons. 
Braidwood 4,641 5,500 1,000— 10,000 ss 
Chenoa 1,226 20,000 
Delavan 1,176 50,000 
Dundee 2,073 70,000 
Earlville 1,058 25,500 
Elmwood 1,548 19,000 7,000—31,000 gallons, 
E] Paso 1,353 27,500 25,000—30,000 “* 
Fairbury 2,324 71,500 53,000 —90,000 « 
Forrest 1,021 8,442 
Geneva 1,692 40,000 Pumpage estimated. 
Lacon 1,649 15,000 
Lexington 1,187 60,000 
Lockport 2,449 44,500 
Minonk 2,316 109,689 
Momence 1,635 250,000 
Morris 3,653 54,795 
Plano 1,825 31,500 
Princeton 3,396 650,000 
Spring Valley 3,837 55,000 
Washington 1,301 100,000 
Wenona 1,053 23,000 21,000—25,000 gallons. 
West Chicago 1,506 20,000 
Total 47,562 1,753,426 Total pumpage, 2.8 cu. ft. 
per sec. 
The principal sources of the sewage contributed to the 
Illinois River above Havana are Chicago, Peoria, and the 
smaller cities within the drainage basin. The amounts 
contributed by each are approximately 520,275,109, 5,000,000, 
and 16,007,378 gallons respectively per day. The total amount 
of 542,282,487 gallons per day or 838.7 cubic feet per second is 
about 8 per cent. of the average flow of the river at Havana and 
exceeds by 40 per cent. the estimated low-water flow at Cop- 
peras Creek dam, eighteen miles above our plankton station. 
In 1890 the population of the two larger cities and the total of 
the remaining smaller ones was respectively 849,850, 41,024, 
and 188,817, a total of 1,079,691, 250,009 having been deducted 
